ad9a9b8e997941640b6de40fd9af4a1b17f39d04
[rpmsg/rpmsg.git] / security / selinux / hooks.c
1 /*
2  *  NSA Security-Enhanced Linux (SELinux) security module
3  *
4  *  This file contains the SELinux hook function implementations.
5  *
6  *  Authors:  Stephen Smalley, <sds@tycho.nsa.gov>
7  *            Chris Vance, <cvance@nai.com>
8  *            Wayne Salamon, <wsalamon@nai.com>
9  *            James Morris <jmorris@redhat.com>
10  *
11  *  Copyright (C) 2001,2002 Networks Associates Technology, Inc.
12  *  Copyright (C) 2003-2008 Red Hat, Inc., James Morris <jmorris@redhat.com>
13  *                                         Eric Paris <eparis@redhat.com>
14  *  Copyright (C) 2004-2005 Trusted Computer Solutions, Inc.
15  *                          <dgoeddel@trustedcs.com>
16  *  Copyright (C) 2006, 2007, 2009 Hewlett-Packard Development Company, L.P.
17  *      Paul Moore <paul@paul-moore.com>
18  *  Copyright (C) 2007 Hitachi Software Engineering Co., Ltd.
19  *                     Yuichi Nakamura <ynakam@hitachisoft.jp>
20  *  Copyright (C) 2016 Mellanox Technologies
21  *
22  *      This program is free software; you can redistribute it and/or modify
23  *      it under the terms of the GNU General Public License version 2,
24  *      as published by the Free Software Foundation.
25  */
27 #include <linux/init.h>
28 #include <linux/kd.h>
29 #include <linux/kernel.h>
30 #include <linux/tracehook.h>
31 #include <linux/errno.h>
32 #include <linux/sched/signal.h>
33 #include <linux/sched/task.h>
34 #include <linux/lsm_hooks.h>
35 #include <linux/xattr.h>
36 #include <linux/capability.h>
37 #include <linux/unistd.h>
38 #include <linux/mm.h>
39 #include <linux/mman.h>
40 #include <linux/slab.h>
41 #include <linux/pagemap.h>
42 #include <linux/proc_fs.h>
43 #include <linux/swap.h>
44 #include <linux/spinlock.h>
45 #include <linux/syscalls.h>
46 #include <linux/dcache.h>
47 #include <linux/file.h>
48 #include <linux/fdtable.h>
49 #include <linux/namei.h>
50 #include <linux/mount.h>
51 #include <linux/netfilter_ipv4.h>
52 #include <linux/netfilter_ipv6.h>
53 #include <linux/tty.h>
54 #include <net/icmp.h>
55 #include <net/ip.h>             /* for local_port_range[] */
56 #include <net/tcp.h>            /* struct or_callable used in sock_rcv_skb */
57 #include <net/inet_connection_sock.h>
58 #include <net/net_namespace.h>
59 #include <net/netlabel.h>
60 #include <linux/uaccess.h>
61 #include <asm/ioctls.h>
62 #include <linux/atomic.h>
63 #include <linux/bitops.h>
64 #include <linux/interrupt.h>
65 #include <linux/netdevice.h>    /* for network interface checks */
66 #include <net/netlink.h>
67 #include <linux/tcp.h>
68 #include <linux/udp.h>
69 #include <linux/dccp.h>
70 #include <linux/sctp.h>
71 #include <net/sctp/structs.h>
72 #include <linux/quota.h>
73 #include <linux/un.h>           /* for Unix socket types */
74 #include <net/af_unix.h>        /* for Unix socket types */
75 #include <linux/parser.h>
76 #include <linux/nfs_mount.h>
77 #include <net/ipv6.h>
78 #include <linux/hugetlb.h>
79 #include <linux/personality.h>
80 #include <linux/audit.h>
81 #include <linux/string.h>
82 #include <linux/selinux.h>
83 #include <linux/mutex.h>
84 #include <linux/posix-timers.h>
85 #include <linux/syslog.h>
86 #include <linux/user_namespace.h>
87 #include <linux/export.h>
88 #include <linux/msg.h>
89 #include <linux/shm.h>
90 #include <linux/bpf.h>
92 #include "avc.h"
93 #include "objsec.h"
94 #include "netif.h"
95 #include "netnode.h"
96 #include "netport.h"
97 #include "ibpkey.h"
98 #include "xfrm.h"
99 #include "netlabel.h"
100 #include "audit.h"
101 #include "avc_ss.h"
103 struct selinux_state selinux_state;
105 /* SECMARK reference count */
106 static atomic_t selinux_secmark_refcount = ATOMIC_INIT(0);
108 #ifdef CONFIG_SECURITY_SELINUX_DEVELOP
109 static int selinux_enforcing_boot;
111 static int __init enforcing_setup(char *str)
113         unsigned long enforcing;
114         if (!kstrtoul(str, 0, &enforcing))
115                 selinux_enforcing_boot = enforcing ? 1 : 0;
116         return 1;
118 __setup("enforcing=", enforcing_setup);
119 #else
120 #define selinux_enforcing_boot 1
121 #endif
123 #ifdef CONFIG_SECURITY_SELINUX_BOOTPARAM
124 int selinux_enabled = CONFIG_SECURITY_SELINUX_BOOTPARAM_VALUE;
126 static int __init selinux_enabled_setup(char *str)
128         unsigned long enabled;
129         if (!kstrtoul(str, 0, &enabled))
130                 selinux_enabled = enabled ? 1 : 0;
131         return 1;
133 __setup("selinux=", selinux_enabled_setup);
134 #else
135 int selinux_enabled = 1;
136 #endif
138 static unsigned int selinux_checkreqprot_boot =
139         CONFIG_SECURITY_SELINUX_CHECKREQPROT_VALUE;
141 static int __init checkreqprot_setup(char *str)
143         unsigned long checkreqprot;
145         if (!kstrtoul(str, 0, &checkreqprot))
146                 selinux_checkreqprot_boot = checkreqprot ? 1 : 0;
147         return 1;
149 __setup("checkreqprot=", checkreqprot_setup);
151 static struct kmem_cache *sel_inode_cache;
152 static struct kmem_cache *file_security_cache;
154 /**
155  * selinux_secmark_enabled - Check to see if SECMARK is currently enabled
156  *
157  * Description:
158  * This function checks the SECMARK reference counter to see if any SECMARK
159  * targets are currently configured, if the reference counter is greater than
160  * zero SECMARK is considered to be enabled.  Returns true (1) if SECMARK is
161  * enabled, false (0) if SECMARK is disabled.  If the always_check_network
162  * policy capability is enabled, SECMARK is always considered enabled.
163  *
164  */
165 static int selinux_secmark_enabled(void)
167         return (selinux_policycap_alwaysnetwork() ||
168                 atomic_read(&selinux_secmark_refcount));
171 /**
172  * selinux_peerlbl_enabled - Check to see if peer labeling is currently enabled
173  *
174  * Description:
175  * This function checks if NetLabel or labeled IPSEC is enabled.  Returns true
176  * (1) if any are enabled or false (0) if neither are enabled.  If the
177  * always_check_network policy capability is enabled, peer labeling
178  * is always considered enabled.
179  *
180  */
181 static int selinux_peerlbl_enabled(void)
183         return (selinux_policycap_alwaysnetwork() ||
184                 netlbl_enabled() || selinux_xfrm_enabled());
187 static int selinux_netcache_avc_callback(u32 event)
189         if (event == AVC_CALLBACK_RESET) {
190                 sel_netif_flush();
191                 sel_netnode_flush();
192                 sel_netport_flush();
193                 synchronize_net();
194         }
195         return 0;
198 static int selinux_lsm_notifier_avc_callback(u32 event)
200         if (event == AVC_CALLBACK_RESET) {
201                 sel_ib_pkey_flush();
202                 call_lsm_notifier(LSM_POLICY_CHANGE, NULL);
203         }
205         return 0;
208 /*
209  * initialise the security for the init task
210  */
211 static void cred_init_security(void)
213         struct cred *cred = (struct cred *) current->real_cred;
214         struct task_security_struct *tsec;
216         tsec = kzalloc(sizeof(struct task_security_struct), GFP_KERNEL);
217         if (!tsec)
218                 panic("SELinux:  Failed to initialize initial task.\n");
220         tsec->osid = tsec->sid = SECINITSID_KERNEL;
221         cred->security = tsec;
224 /*
225  * get the security ID of a set of credentials
226  */
227 static inline u32 cred_sid(const struct cred *cred)
229         const struct task_security_struct *tsec;
231         tsec = cred->security;
232         return tsec->sid;
235 /*
236  * get the objective security ID of a task
237  */
238 static inline u32 task_sid(const struct task_struct *task)
240         u32 sid;
242         rcu_read_lock();
243         sid = cred_sid(__task_cred(task));
244         rcu_read_unlock();
245         return sid;
248 /* Allocate and free functions for each kind of security blob. */
250 static int inode_alloc_security(struct inode *inode)
252         struct inode_security_struct *isec;
253         u32 sid = current_sid();
255         isec = kmem_cache_zalloc(sel_inode_cache, GFP_NOFS);
256         if (!isec)
257                 return -ENOMEM;
259         spin_lock_init(&isec->lock);
260         INIT_LIST_HEAD(&isec->list);
261         isec->inode = inode;
262         isec->sid = SECINITSID_UNLABELED;
263         isec->sclass = SECCLASS_FILE;
264         isec->task_sid = sid;
265         isec->initialized = LABEL_INVALID;
266         inode->i_security = isec;
268         return 0;
271 static int inode_doinit_with_dentry(struct inode *inode, struct dentry *opt_dentry);
273 /*
274  * Try reloading inode security labels that have been marked as invalid.  The
275  * @may_sleep parameter indicates when sleeping and thus reloading labels is
276  * allowed; when set to false, returns -ECHILD when the label is
277  * invalid.  The @dentry parameter should be set to a dentry of the inode.
278  */
279 static int __inode_security_revalidate(struct inode *inode,
280                                        struct dentry *dentry,
281                                        bool may_sleep)
283         struct inode_security_struct *isec = inode->i_security;
285         might_sleep_if(may_sleep);
287         if (selinux_state.initialized &&
288             isec->initialized != LABEL_INITIALIZED) {
289                 if (!may_sleep)
290                         return -ECHILD;
292                 /*
293                  * Try reloading the inode security label.  This will fail if
294                  * @opt_dentry is NULL and no dentry for this inode can be
295                  * found; in that case, continue using the old label.
296                  */
297                 inode_doinit_with_dentry(inode, dentry);
298         }
299         return 0;
302 static struct inode_security_struct *inode_security_novalidate(struct inode *inode)
304         return inode->i_security;
307 static struct inode_security_struct *inode_security_rcu(struct inode *inode, bool rcu)
309         int error;
311         error = __inode_security_revalidate(inode, NULL, !rcu);
312         if (error)
313                 return ERR_PTR(error);
314         return inode->i_security;
317 /*
318  * Get the security label of an inode.
319  */
320 static struct inode_security_struct *inode_security(struct inode *inode)
322         __inode_security_revalidate(inode, NULL, true);
323         return inode->i_security;
326 static struct inode_security_struct *backing_inode_security_novalidate(struct dentry *dentry)
328         struct inode *inode = d_backing_inode(dentry);
330         return inode->i_security;
333 /*
334  * Get the security label of a dentry's backing inode.
335  */
336 static struct inode_security_struct *backing_inode_security(struct dentry *dentry)
338         struct inode *inode = d_backing_inode(dentry);
340         __inode_security_revalidate(inode, dentry, true);
341         return inode->i_security;
344 static void inode_free_rcu(struct rcu_head *head)
346         struct inode_security_struct *isec;
348         isec = container_of(head, struct inode_security_struct, rcu);
349         kmem_cache_free(sel_inode_cache, isec);
352 static void inode_free_security(struct inode *inode)
354         struct inode_security_struct *isec = inode->i_security;
355         struct superblock_security_struct *sbsec = inode->i_sb->s_security;
357         /*
358          * As not all inode security structures are in a list, we check for
359          * empty list outside of the lock to make sure that we won't waste
360          * time taking a lock doing nothing.
361          *
362          * The list_del_init() function can be safely called more than once.
363          * It should not be possible for this function to be called with
364          * concurrent list_add(), but for better safety against future changes
365          * in the code, we use list_empty_careful() here.
366          */
367         if (!list_empty_careful(&isec->list)) {
368                 spin_lock(&sbsec->isec_lock);
369                 list_del_init(&isec->list);
370                 spin_unlock(&sbsec->isec_lock);
371         }
373         /*
374          * The inode may still be referenced in a path walk and
375          * a call to selinux_inode_permission() can be made
376          * after inode_free_security() is called. Ideally, the VFS
377          * wouldn't do this, but fixing that is a much harder
378          * job. For now, simply free the i_security via RCU, and
379          * leave the current inode->i_security pointer intact.
380          * The inode will be freed after the RCU grace period too.
381          */
382         call_rcu(&isec->rcu, inode_free_rcu);
385 static int file_alloc_security(struct file *file)
387         struct file_security_struct *fsec;
388         u32 sid = current_sid();
390         fsec = kmem_cache_zalloc(file_security_cache, GFP_KERNEL);
391         if (!fsec)
392                 return -ENOMEM;
394         fsec->sid = sid;
395         fsec->fown_sid = sid;
396         file->f_security = fsec;
398         return 0;
401 static void file_free_security(struct file *file)
403         struct file_security_struct *fsec = file->f_security;
404         file->f_security = NULL;
405         kmem_cache_free(file_security_cache, fsec);
408 static int superblock_alloc_security(struct super_block *sb)
410         struct superblock_security_struct *sbsec;
412         sbsec = kzalloc(sizeof(struct superblock_security_struct), GFP_KERNEL);
413         if (!sbsec)
414                 return -ENOMEM;
416         mutex_init(&sbsec->lock);
417         INIT_LIST_HEAD(&sbsec->isec_head);
418         spin_lock_init(&sbsec->isec_lock);
419         sbsec->sb = sb;
420         sbsec->sid = SECINITSID_UNLABELED;
421         sbsec->def_sid = SECINITSID_FILE;
422         sbsec->mntpoint_sid = SECINITSID_UNLABELED;
423         sb->s_security = sbsec;
425         return 0;
428 static void superblock_free_security(struct super_block *sb)
430         struct superblock_security_struct *sbsec = sb->s_security;
431         sb->s_security = NULL;
432         kfree(sbsec);
435 static inline int inode_doinit(struct inode *inode)
437         return inode_doinit_with_dentry(inode, NULL);
440 enum {
441         Opt_error = -1,
442         Opt_context = 1,
443         Opt_fscontext = 2,
444         Opt_defcontext = 3,
445         Opt_rootcontext = 4,
446         Opt_labelsupport = 5,
447         Opt_nextmntopt = 6,
448 };
450 #define NUM_SEL_MNT_OPTS        (Opt_nextmntopt - 1)
452 static const match_table_t tokens = {
453         {Opt_context, CONTEXT_STR "%s"},
454         {Opt_fscontext, FSCONTEXT_STR "%s"},
455         {Opt_defcontext, DEFCONTEXT_STR "%s"},
456         {Opt_rootcontext, ROOTCONTEXT_STR "%s"},
457         {Opt_labelsupport, LABELSUPP_STR},
458         {Opt_error, NULL},
459 };
461 #define SEL_MOUNT_FAIL_MSG "SELinux:  duplicate or incompatible mount options\n"
463 static int may_context_mount_sb_relabel(u32 sid,
464                         struct superblock_security_struct *sbsec,
465                         const struct cred *cred)
467         const struct task_security_struct *tsec = cred->security;
468         int rc;
470         rc = avc_has_perm(&selinux_state,
471                           tsec->sid, sbsec->sid, SECCLASS_FILESYSTEM,
472                           FILESYSTEM__RELABELFROM, NULL);
473         if (rc)
474                 return rc;
476         rc = avc_has_perm(&selinux_state,
477                           tsec->sid, sid, SECCLASS_FILESYSTEM,
478                           FILESYSTEM__RELABELTO, NULL);
479         return rc;
482 static int may_context_mount_inode_relabel(u32 sid,
483                         struct superblock_security_struct *sbsec,
484                         const struct cred *cred)
486         const struct task_security_struct *tsec = cred->security;
487         int rc;
488         rc = avc_has_perm(&selinux_state,
489                           tsec->sid, sbsec->sid, SECCLASS_FILESYSTEM,
490                           FILESYSTEM__RELABELFROM, NULL);
491         if (rc)
492                 return rc;
494         rc = avc_has_perm(&selinux_state,
495                           sid, sbsec->sid, SECCLASS_FILESYSTEM,
496                           FILESYSTEM__ASSOCIATE, NULL);
497         return rc;
500 static int selinux_is_sblabel_mnt(struct super_block *sb)
502         struct superblock_security_struct *sbsec = sb->s_security;
504         return sbsec->behavior == SECURITY_FS_USE_XATTR ||
505                 sbsec->behavior == SECURITY_FS_USE_TRANS ||
506                 sbsec->behavior == SECURITY_FS_USE_TASK ||
507                 sbsec->behavior == SECURITY_FS_USE_NATIVE ||
508                 /* Special handling. Genfs but also in-core setxattr handler */
509                 !strcmp(sb->s_type->name, "sysfs") ||
510                 !strcmp(sb->s_type->name, "pstore") ||
511                 !strcmp(sb->s_type->name, "debugfs") ||
512                 !strcmp(sb->s_type->name, "tracefs") ||
513                 !strcmp(sb->s_type->name, "rootfs") ||
514                 (selinux_policycap_cgroupseclabel() &&
515                  (!strcmp(sb->s_type->name, "cgroup") ||
516                   !strcmp(sb->s_type->name, "cgroup2")));
519 static int sb_finish_set_opts(struct super_block *sb)
521         struct superblock_security_struct *sbsec = sb->s_security;
522         struct dentry *root = sb->s_root;
523         struct inode *root_inode = d_backing_inode(root);
524         int rc = 0;
526         if (sbsec->behavior == SECURITY_FS_USE_XATTR) {
527                 /* Make sure that the xattr handler exists and that no
528                    error other than -ENODATA is returned by getxattr on
529                    the root directory.  -ENODATA is ok, as this may be
530                    the first boot of the SELinux kernel before we have
531                    assigned xattr values to the filesystem. */
532                 if (!(root_inode->i_opflags & IOP_XATTR)) {
533                         pr_warn("SELinux: (dev %s, type %s) has no "
534                                "xattr support\n", sb->s_id, sb->s_type->name);
535                         rc = -EOPNOTSUPP;
536                         goto out;
537                 }
539                 rc = __vfs_getxattr(root, root_inode, XATTR_NAME_SELINUX, NULL, 0);
540                 if (rc < 0 && rc != -ENODATA) {
541                         if (rc == -EOPNOTSUPP)
542                                 pr_warn("SELinux: (dev %s, type "
543                                        "%s) has no security xattr handler\n",
544                                        sb->s_id, sb->s_type->name);
545                         else
546                                 pr_warn("SELinux: (dev %s, type "
547                                        "%s) getxattr errno %d\n", sb->s_id,
548                                        sb->s_type->name, -rc);
549                         goto out;
550                 }
551         }
553         sbsec->flags |= SE_SBINITIALIZED;
555         /*
556          * Explicitly set or clear SBLABEL_MNT.  It's not sufficient to simply
557          * leave the flag untouched because sb_clone_mnt_opts might be handing
558          * us a superblock that needs the flag to be cleared.
559          */
560         if (selinux_is_sblabel_mnt(sb))
561                 sbsec->flags |= SBLABEL_MNT;
562         else
563                 sbsec->flags &= ~SBLABEL_MNT;
565         /* Initialize the root inode. */
566         rc = inode_doinit_with_dentry(root_inode, root);
568         /* Initialize any other inodes associated with the superblock, e.g.
569            inodes created prior to initial policy load or inodes created
570            during get_sb by a pseudo filesystem that directly
571            populates itself. */
572         spin_lock(&sbsec->isec_lock);
573 next_inode:
574         if (!list_empty(&sbsec->isec_head)) {
575                 struct inode_security_struct *isec =
576                                 list_entry(sbsec->isec_head.next,
577                                            struct inode_security_struct, list);
578                 struct inode *inode = isec->inode;
579                 list_del_init(&isec->list);
580                 spin_unlock(&sbsec->isec_lock);
581                 inode = igrab(inode);
582                 if (inode) {
583                         if (!IS_PRIVATE(inode))
584                                 inode_doinit(inode);
585                         iput(inode);
586                 }
587                 spin_lock(&sbsec->isec_lock);
588                 goto next_inode;
589         }
590         spin_unlock(&sbsec->isec_lock);
591 out:
592         return rc;
595 /*
596  * This function should allow an FS to ask what it's mount security
597  * options were so it can use those later for submounts, displaying
598  * mount options, or whatever.
599  */
600 static int selinux_get_mnt_opts(const struct super_block *sb,
601                                 struct security_mnt_opts *opts)
603         int rc = 0, i;
604         struct superblock_security_struct *sbsec = sb->s_security;
605         char *context = NULL;
606         u32 len;
607         char tmp;
609         security_init_mnt_opts(opts);
611         if (!(sbsec->flags & SE_SBINITIALIZED))
612                 return -EINVAL;
614         if (!selinux_state.initialized)
615                 return -EINVAL;
617         /* make sure we always check enough bits to cover the mask */
618         BUILD_BUG_ON(SE_MNTMASK >= (1 << NUM_SEL_MNT_OPTS));
620         tmp = sbsec->flags & SE_MNTMASK;
621         /* count the number of mount options for this sb */
622         for (i = 0; i < NUM_SEL_MNT_OPTS; i++) {
623                 if (tmp & 0x01)
624                         opts->num_mnt_opts++;
625                 tmp >>= 1;
626         }
627         /* Check if the Label support flag is set */
628         if (sbsec->flags & SBLABEL_MNT)
629                 opts->num_mnt_opts++;
631         opts->mnt_opts = kcalloc(opts->num_mnt_opts, sizeof(char *), GFP_ATOMIC);
632         if (!opts->mnt_opts) {
633                 rc = -ENOMEM;
634                 goto out_free;
635         }
637         opts->mnt_opts_flags = kcalloc(opts->num_mnt_opts, sizeof(int), GFP_ATOMIC);
638         if (!opts->mnt_opts_flags) {
639                 rc = -ENOMEM;
640                 goto out_free;
641         }
643         i = 0;
644         if (sbsec->flags & FSCONTEXT_MNT) {
645                 rc = security_sid_to_context(&selinux_state, sbsec->sid,
646                                              &context, &len);
647                 if (rc)
648                         goto out_free;
649                 opts->mnt_opts[i] = context;
650                 opts->mnt_opts_flags[i++] = FSCONTEXT_MNT;
651         }
652         if (sbsec->flags & CONTEXT_MNT) {
653                 rc = security_sid_to_context(&selinux_state,
654                                              sbsec->mntpoint_sid,
655                                              &context, &len);
656                 if (rc)
657                         goto out_free;
658                 opts->mnt_opts[i] = context;
659                 opts->mnt_opts_flags[i++] = CONTEXT_MNT;
660         }
661         if (sbsec->flags & DEFCONTEXT_MNT) {
662                 rc = security_sid_to_context(&selinux_state, sbsec->def_sid,
663                                              &context, &len);
664                 if (rc)
665                         goto out_free;
666                 opts->mnt_opts[i] = context;
667                 opts->mnt_opts_flags[i++] = DEFCONTEXT_MNT;
668         }
669         if (sbsec->flags & ROOTCONTEXT_MNT) {
670                 struct dentry *root = sbsec->sb->s_root;
671                 struct inode_security_struct *isec = backing_inode_security(root);
673                 rc = security_sid_to_context(&selinux_state, isec->sid,
674                                              &context, &len);
675                 if (rc)
676                         goto out_free;
677                 opts->mnt_opts[i] = context;
678                 opts->mnt_opts_flags[i++] = ROOTCONTEXT_MNT;
679         }
680         if (sbsec->flags & SBLABEL_MNT) {
681                 opts->mnt_opts[i] = NULL;
682                 opts->mnt_opts_flags[i++] = SBLABEL_MNT;
683         }
685         BUG_ON(i != opts->num_mnt_opts);
687         return 0;
689 out_free:
690         security_free_mnt_opts(opts);
691         return rc;
694 static int bad_option(struct superblock_security_struct *sbsec, char flag,
695                       u32 old_sid, u32 new_sid)
697         char mnt_flags = sbsec->flags & SE_MNTMASK;
699         /* check if the old mount command had the same options */
700         if (sbsec->flags & SE_SBINITIALIZED)
701                 if (!(sbsec->flags & flag) ||
702                     (old_sid != new_sid))
703                         return 1;
705         /* check if we were passed the same options twice,
706          * aka someone passed context=a,context=b
707          */
708         if (!(sbsec->flags & SE_SBINITIALIZED))
709                 if (mnt_flags & flag)
710                         return 1;
711         return 0;
714 /*
715  * Allow filesystems with binary mount data to explicitly set mount point
716  * labeling information.
717  */
718 static int selinux_set_mnt_opts(struct super_block *sb,
719                                 struct security_mnt_opts *opts,
720                                 unsigned long kern_flags,
721                                 unsigned long *set_kern_flags)
723         const struct cred *cred = current_cred();
724         int rc = 0, i;
725         struct superblock_security_struct *sbsec = sb->s_security;
726         const char *name = sb->s_type->name;
727         struct dentry *root = sbsec->sb->s_root;
728         struct inode_security_struct *root_isec;
729         u32 fscontext_sid = 0, context_sid = 0, rootcontext_sid = 0;
730         u32 defcontext_sid = 0;
731         char **mount_options = opts->mnt_opts;
732         int *flags = opts->mnt_opts_flags;
733         int num_opts = opts->num_mnt_opts;
735         mutex_lock(&sbsec->lock);
737         if (!selinux_state.initialized) {
738                 if (!num_opts) {
739                         /* Defer initialization until selinux_complete_init,
740                            after the initial policy is loaded and the security
741                            server is ready to handle calls. */
742                         goto out;
743                 }
744                 rc = -EINVAL;
745                 pr_warn("SELinux: Unable to set superblock options "
746                         "before the security server is initialized\n");
747                 goto out;
748         }
749         if (kern_flags && !set_kern_flags) {
750                 /* Specifying internal flags without providing a place to
751                  * place the results is not allowed */
752                 rc = -EINVAL;
753                 goto out;
754         }
756         /*
757          * Binary mount data FS will come through this function twice.  Once
758          * from an explicit call and once from the generic calls from the vfs.
759          * Since the generic VFS calls will not contain any security mount data
760          * we need to skip the double mount verification.
761          *
762          * This does open a hole in which we will not notice if the first
763          * mount using this sb set explict options and a second mount using
764          * this sb does not set any security options.  (The first options
765          * will be used for both mounts)
766          */
767         if ((sbsec->flags & SE_SBINITIALIZED) && (sb->s_type->fs_flags & FS_BINARY_MOUNTDATA)
768             && (num_opts == 0))
769                 goto out;
771         root_isec = backing_inode_security_novalidate(root);
773         /*
774          * parse the mount options, check if they are valid sids.
775          * also check if someone is trying to mount the same sb more
776          * than once with different security options.
777          */
778         for (i = 0; i < num_opts; i++) {
779                 u32 sid;
781                 if (flags[i] == SBLABEL_MNT)
782                         continue;
783                 rc = security_context_str_to_sid(&selinux_state,
784                                                  mount_options[i], &sid,
785                                                  GFP_KERNEL);
786                 if (rc) {
787                         pr_warn("SELinux: security_context_str_to_sid"
788                                "(%s) failed for (dev %s, type %s) errno=%d\n",
789                                mount_options[i], sb->s_id, name, rc);
790                         goto out;
791                 }
792                 switch (flags[i]) {
793                 case FSCONTEXT_MNT:
794                         fscontext_sid = sid;
796                         if (bad_option(sbsec, FSCONTEXT_MNT, sbsec->sid,
797                                         fscontext_sid))
798                                 goto out_double_mount;
800                         sbsec->flags |= FSCONTEXT_MNT;
801                         break;
802                 case CONTEXT_MNT:
803                         context_sid = sid;
805                         if (bad_option(sbsec, CONTEXT_MNT, sbsec->mntpoint_sid,
806                                         context_sid))
807                                 goto out_double_mount;
809                         sbsec->flags |= CONTEXT_MNT;
810                         break;
811                 case ROOTCONTEXT_MNT:
812                         rootcontext_sid = sid;
814                         if (bad_option(sbsec, ROOTCONTEXT_MNT, root_isec->sid,
815                                         rootcontext_sid))
816                                 goto out_double_mount;
818                         sbsec->flags |= ROOTCONTEXT_MNT;
820                         break;
821                 case DEFCONTEXT_MNT:
822                         defcontext_sid = sid;
824                         if (bad_option(sbsec, DEFCONTEXT_MNT, sbsec->def_sid,
825                                         defcontext_sid))
826                                 goto out_double_mount;
828                         sbsec->flags |= DEFCONTEXT_MNT;
830                         break;
831                 default:
832                         rc = -EINVAL;
833                         goto out;
834                 }
835         }
837         if (sbsec->flags & SE_SBINITIALIZED) {
838                 /* previously mounted with options, but not on this attempt? */
839                 if ((sbsec->flags & SE_MNTMASK) && !num_opts)
840                         goto out_double_mount;
841                 rc = 0;
842                 goto out;
843         }
845         if (strcmp(sb->s_type->name, "proc") == 0)
846                 sbsec->flags |= SE_SBPROC | SE_SBGENFS;
848         if (!strcmp(sb->s_type->name, "debugfs") ||
849             !strcmp(sb->s_type->name, "tracefs") ||
850             !strcmp(sb->s_type->name, "sysfs") ||
851             !strcmp(sb->s_type->name, "pstore") ||
852             !strcmp(sb->s_type->name, "cgroup") ||
853             !strcmp(sb->s_type->name, "cgroup2"))
854                 sbsec->flags |= SE_SBGENFS;
856         if (!sbsec->behavior) {
857                 /*
858                  * Determine the labeling behavior to use for this
859                  * filesystem type.
860                  */
861                 rc = security_fs_use(&selinux_state, sb);
862                 if (rc) {
863                         pr_warn("%s: security_fs_use(%s) returned %d\n",
864                                         __func__, sb->s_type->name, rc);
865                         goto out;
866                 }
867         }
869         /*
870          * If this is a user namespace mount and the filesystem type is not
871          * explicitly whitelisted, then no contexts are allowed on the command
872          * line and security labels must be ignored.
873          */
874         if (sb->s_user_ns != &init_user_ns &&
875             strcmp(sb->s_type->name, "tmpfs") &&
876             strcmp(sb->s_type->name, "ramfs") &&
877             strcmp(sb->s_type->name, "devpts")) {
878                 if (context_sid || fscontext_sid || rootcontext_sid ||
879                     defcontext_sid) {
880                         rc = -EACCES;
881                         goto out;
882                 }
883                 if (sbsec->behavior == SECURITY_FS_USE_XATTR) {
884                         sbsec->behavior = SECURITY_FS_USE_MNTPOINT;
885                         rc = security_transition_sid(&selinux_state,
886                                                      current_sid(),
887                                                      current_sid(),
888                                                      SECCLASS_FILE, NULL,
889                                                      &sbsec->mntpoint_sid);
890                         if (rc)
891                                 goto out;
892                 }
893                 goto out_set_opts;
894         }
896         /* sets the context of the superblock for the fs being mounted. */
897         if (fscontext_sid) {
898                 rc = may_context_mount_sb_relabel(fscontext_sid, sbsec, cred);
899                 if (rc)
900                         goto out;
902                 sbsec->sid = fscontext_sid;
903         }
905         /*
906          * Switch to using mount point labeling behavior.
907          * sets the label used on all file below the mountpoint, and will set
908          * the superblock context if not already set.
909          */
910         if (kern_flags & SECURITY_LSM_NATIVE_LABELS && !context_sid) {
911                 sbsec->behavior = SECURITY_FS_USE_NATIVE;
912                 *set_kern_flags |= SECURITY_LSM_NATIVE_LABELS;
913         }
915         if (context_sid) {
916                 if (!fscontext_sid) {
917                         rc = may_context_mount_sb_relabel(context_sid, sbsec,
918                                                           cred);
919                         if (rc)
920                                 goto out;
921                         sbsec->sid = context_sid;
922                 } else {
923                         rc = may_context_mount_inode_relabel(context_sid, sbsec,
924                                                              cred);
925                         if (rc)
926                                 goto out;
927                 }
928                 if (!rootcontext_sid)
929                         rootcontext_sid = context_sid;
931                 sbsec->mntpoint_sid = context_sid;
932                 sbsec->behavior = SECURITY_FS_USE_MNTPOINT;
933         }
935         if (rootcontext_sid) {
936                 rc = may_context_mount_inode_relabel(rootcontext_sid, sbsec,
937                                                      cred);
938                 if (rc)
939                         goto out;
941                 root_isec->sid = rootcontext_sid;
942                 root_isec->initialized = LABEL_INITIALIZED;
943         }
945         if (defcontext_sid) {
946                 if (sbsec->behavior != SECURITY_FS_USE_XATTR &&
947                         sbsec->behavior != SECURITY_FS_USE_NATIVE) {
948                         rc = -EINVAL;
949                         pr_warn("SELinux: defcontext option is "
950                                "invalid for this filesystem type\n");
951                         goto out;
952                 }
954                 if (defcontext_sid != sbsec->def_sid) {
955                         rc = may_context_mount_inode_relabel(defcontext_sid,
956                                                              sbsec, cred);
957                         if (rc)
958                                 goto out;
959                 }
961                 sbsec->def_sid = defcontext_sid;
962         }
964 out_set_opts:
965         rc = sb_finish_set_opts(sb);
966 out:
967         mutex_unlock(&sbsec->lock);
968         return rc;
969 out_double_mount:
970         rc = -EINVAL;
971         pr_warn("SELinux: mount invalid.  Same superblock, different "
972                "security settings for (dev %s, type %s)\n", sb->s_id, name);
973         goto out;
976 static int selinux_cmp_sb_context(const struct super_block *oldsb,
977                                     const struct super_block *newsb)
979         struct superblock_security_struct *old = oldsb->s_security;
980         struct superblock_security_struct *new = newsb->s_security;
981         char oldflags = old->flags & SE_MNTMASK;
982         char newflags = new->flags & SE_MNTMASK;
984         if (oldflags != newflags)
985                 goto mismatch;
986         if ((oldflags & FSCONTEXT_MNT) && old->sid != new->sid)
987                 goto mismatch;
988         if ((oldflags & CONTEXT_MNT) && old->mntpoint_sid != new->mntpoint_sid)
989                 goto mismatch;
990         if ((oldflags & DEFCONTEXT_MNT) && old->def_sid != new->def_sid)
991                 goto mismatch;
992         if (oldflags & ROOTCONTEXT_MNT) {
993                 struct inode_security_struct *oldroot = backing_inode_security(oldsb->s_root);
994                 struct inode_security_struct *newroot = backing_inode_security(newsb->s_root);
995                 if (oldroot->sid != newroot->sid)
996                         goto mismatch;
997         }
998         return 0;
999 mismatch:
1000         pr_warn("SELinux: mount invalid.  Same superblock, "
1001                             "different security settings for (dev %s, "
1002                             "type %s)\n", newsb->s_id, newsb->s_type->name);
1003         return -EBUSY;
1006 static int selinux_sb_clone_mnt_opts(const struct super_block *oldsb,
1007                                         struct super_block *newsb,
1008                                         unsigned long kern_flags,
1009                                         unsigned long *set_kern_flags)
1011         int rc = 0;
1012         const struct superblock_security_struct *oldsbsec = oldsb->s_security;
1013         struct superblock_security_struct *newsbsec = newsb->s_security;
1015         int set_fscontext =     (oldsbsec->flags & FSCONTEXT_MNT);
1016         int set_context =       (oldsbsec->flags & CONTEXT_MNT);
1017         int set_rootcontext =   (oldsbsec->flags & ROOTCONTEXT_MNT);
1019         /*
1020          * if the parent was able to be mounted it clearly had no special lsm
1021          * mount options.  thus we can safely deal with this superblock later
1022          */
1023         if (!selinux_state.initialized)
1024                 return 0;
1026         /*
1027          * Specifying internal flags without providing a place to
1028          * place the results is not allowed.
1029          */
1030         if (kern_flags && !set_kern_flags)
1031                 return -EINVAL;
1033         /* how can we clone if the old one wasn't set up?? */
1034         BUG_ON(!(oldsbsec->flags & SE_SBINITIALIZED));
1036         /* if fs is reusing a sb, make sure that the contexts match */
1037         if (newsbsec->flags & SE_SBINITIALIZED)
1038                 return selinux_cmp_sb_context(oldsb, newsb);
1040         mutex_lock(&newsbsec->lock);
1042         newsbsec->flags = oldsbsec->flags;
1044         newsbsec->sid = oldsbsec->sid;
1045         newsbsec->def_sid = oldsbsec->def_sid;
1046         newsbsec->behavior = oldsbsec->behavior;
1048         if (newsbsec->behavior == SECURITY_FS_USE_NATIVE &&
1049                 !(kern_flags & SECURITY_LSM_NATIVE_LABELS) && !set_context) {
1050                 rc = security_fs_use(&selinux_state, newsb);
1051                 if (rc)
1052                         goto out;
1053         }
1055         if (kern_flags & SECURITY_LSM_NATIVE_LABELS && !set_context) {
1056                 newsbsec->behavior = SECURITY_FS_USE_NATIVE;
1057                 *set_kern_flags |= SECURITY_LSM_NATIVE_LABELS;
1058         }
1060         if (set_context) {
1061                 u32 sid = oldsbsec->mntpoint_sid;
1063                 if (!set_fscontext)
1064                         newsbsec->sid = sid;
1065                 if (!set_rootcontext) {
1066                         struct inode_security_struct *newisec = backing_inode_security(newsb->s_root);
1067                         newisec->sid = sid;
1068                 }
1069                 newsbsec->mntpoint_sid = sid;
1070         }
1071         if (set_rootcontext) {
1072                 const struct inode_security_struct *oldisec = backing_inode_security(oldsb->s_root);
1073                 struct inode_security_struct *newisec = backing_inode_security(newsb->s_root);
1075                 newisec->sid = oldisec->sid;
1076         }
1078         sb_finish_set_opts(newsb);
1079 out:
1080         mutex_unlock(&newsbsec->lock);
1081         return rc;
1084 static int selinux_parse_opts_str(char *options,
1085                                   struct security_mnt_opts *opts)
1087         char *p;
1088         char *context = NULL, *defcontext = NULL;
1089         char *fscontext = NULL, *rootcontext = NULL;
1090         int rc, num_mnt_opts = 0;
1092         opts->num_mnt_opts = 0;
1094         /* Standard string-based options. */
1095         while ((p = strsep(&options, "|")) != NULL) {
1096                 int token;
1097                 substring_t args[MAX_OPT_ARGS];
1099                 if (!*p)
1100                         continue;
1102                 token = match_token(p, tokens, args);
1104                 switch (token) {
1105                 case Opt_context:
1106                         if (context || defcontext) {
1107                                 rc = -EINVAL;
1108                                 pr_warn(SEL_MOUNT_FAIL_MSG);
1109                                 goto out_err;
1110                         }
1111                         context = match_strdup(&args[0]);
1112                         if (!context) {
1113                                 rc = -ENOMEM;
1114                                 goto out_err;
1115                         }
1116                         break;
1118                 case Opt_fscontext:
1119                         if (fscontext) {
1120                                 rc = -EINVAL;
1121                                 pr_warn(SEL_MOUNT_FAIL_MSG);
1122                                 goto out_err;
1123                         }
1124                         fscontext = match_strdup(&args[0]);
1125                         if (!fscontext) {
1126                                 rc = -ENOMEM;
1127                                 goto out_err;
1128                         }
1129                         break;
1131                 case Opt_rootcontext:
1132                         if (rootcontext) {
1133                                 rc = -EINVAL;
1134                                 pr_warn(SEL_MOUNT_FAIL_MSG);
1135                                 goto out_err;
1136                         }
1137                         rootcontext = match_strdup(&args[0]);
1138                         if (!rootcontext) {
1139                                 rc = -ENOMEM;
1140                                 goto out_err;
1141                         }
1142                         break;
1144                 case Opt_defcontext:
1145                         if (context || defcontext) {
1146                                 rc = -EINVAL;
1147                                 pr_warn(SEL_MOUNT_FAIL_MSG);
1148                                 goto out_err;
1149                         }
1150                         defcontext = match_strdup(&args[0]);
1151                         if (!defcontext) {
1152                                 rc = -ENOMEM;
1153                                 goto out_err;
1154                         }
1155                         break;
1156                 case Opt_labelsupport:
1157                         break;
1158                 default:
1159                         rc = -EINVAL;
1160                         pr_warn("SELinux:  unknown mount option\n");
1161                         goto out_err;
1163                 }
1164         }
1166         rc = -ENOMEM;
1167         opts->mnt_opts = kcalloc(NUM_SEL_MNT_OPTS, sizeof(char *), GFP_KERNEL);
1168         if (!opts->mnt_opts)
1169                 goto out_err;
1171         opts->mnt_opts_flags = kcalloc(NUM_SEL_MNT_OPTS, sizeof(int),
1172                                        GFP_KERNEL);
1173         if (!opts->mnt_opts_flags)
1174                 goto out_err;
1176         if (fscontext) {
1177                 opts->mnt_opts[num_mnt_opts] = fscontext;
1178                 opts->mnt_opts_flags[num_mnt_opts++] = FSCONTEXT_MNT;
1179         }
1180         if (context) {
1181                 opts->mnt_opts[num_mnt_opts] = context;
1182                 opts->mnt_opts_flags[num_mnt_opts++] = CONTEXT_MNT;
1183         }
1184         if (rootcontext) {
1185                 opts->mnt_opts[num_mnt_opts] = rootcontext;
1186                 opts->mnt_opts_flags[num_mnt_opts++] = ROOTCONTEXT_MNT;
1187         }
1188         if (defcontext) {
1189                 opts->mnt_opts[num_mnt_opts] = defcontext;
1190                 opts->mnt_opts_flags[num_mnt_opts++] = DEFCONTEXT_MNT;
1191         }
1193         opts->num_mnt_opts = num_mnt_opts;
1194         return 0;
1196 out_err:
1197         security_free_mnt_opts(opts);
1198         kfree(context);
1199         kfree(defcontext);
1200         kfree(fscontext);
1201         kfree(rootcontext);
1202         return rc;
1204 /*
1205  * string mount options parsing and call set the sbsec
1206  */
1207 static int superblock_doinit(struct super_block *sb, void *data)
1209         int rc = 0;
1210         char *options = data;
1211         struct security_mnt_opts opts;
1213         security_init_mnt_opts(&opts);
1215         if (!data)
1216                 goto out;
1218         BUG_ON(sb->s_type->fs_flags & FS_BINARY_MOUNTDATA);
1220         rc = selinux_parse_opts_str(options, &opts);
1221         if (rc)
1222                 goto out_err;
1224 out:
1225         rc = selinux_set_mnt_opts(sb, &opts, 0, NULL);
1227 out_err:
1228         security_free_mnt_opts(&opts);
1229         return rc;
1232 static void selinux_write_opts(struct seq_file *m,
1233                                struct security_mnt_opts *opts)
1235         int i;
1236         char *prefix;
1238         for (i = 0; i < opts->num_mnt_opts; i++) {
1239                 char *has_comma;
1241                 if (opts->mnt_opts[i])
1242                         has_comma = strchr(opts->mnt_opts[i], ',');
1243                 else
1244                         has_comma = NULL;
1246                 switch (opts->mnt_opts_flags[i]) {
1247                 case CONTEXT_MNT:
1248                         prefix = CONTEXT_STR;
1249                         break;
1250                 case FSCONTEXT_MNT:
1251                         prefix = FSCONTEXT_STR;
1252                         break;
1253                 case ROOTCONTEXT_MNT:
1254                         prefix = ROOTCONTEXT_STR;
1255                         break;
1256                 case DEFCONTEXT_MNT:
1257                         prefix = DEFCONTEXT_STR;
1258                         break;
1259                 case SBLABEL_MNT:
1260                         seq_putc(m, ',');
1261                         seq_puts(m, LABELSUPP_STR);
1262                         continue;
1263                 default:
1264                         BUG();
1265                         return;
1266                 };
1267                 /* we need a comma before each option */
1268                 seq_putc(m, ',');
1269                 seq_puts(m, prefix);
1270                 if (has_comma)
1271                         seq_putc(m, '\"');
1272                 seq_escape(m, opts->mnt_opts[i], "\"\n\\");
1273                 if (has_comma)
1274                         seq_putc(m, '\"');
1275         }
1278 static int selinux_sb_show_options(struct seq_file *m, struct super_block *sb)
1280         struct security_mnt_opts opts;
1281         int rc;
1283         rc = selinux_get_mnt_opts(sb, &opts);
1284         if (rc) {
1285                 /* before policy load we may get EINVAL, don't show anything */
1286                 if (rc == -EINVAL)
1287                         rc = 0;
1288                 return rc;
1289         }
1291         selinux_write_opts(m, &opts);
1293         security_free_mnt_opts(&opts);
1295         return rc;
1298 static inline u16 inode_mode_to_security_class(umode_t mode)
1300         switch (mode & S_IFMT) {
1301         case S_IFSOCK:
1302                 return SECCLASS_SOCK_FILE;
1303         case S_IFLNK:
1304                 return SECCLASS_LNK_FILE;
1305         case S_IFREG:
1306                 return SECCLASS_FILE;
1307         case S_IFBLK:
1308                 return SECCLASS_BLK_FILE;
1309         case S_IFDIR:
1310                 return SECCLASS_DIR;
1311         case S_IFCHR:
1312                 return SECCLASS_CHR_FILE;
1313         case S_IFIFO:
1314                 return SECCLASS_FIFO_FILE;
1316         }
1318         return SECCLASS_FILE;
1321 static inline int default_protocol_stream(int protocol)
1323         return (protocol == IPPROTO_IP || protocol == IPPROTO_TCP);
1326 static inline int default_protocol_dgram(int protocol)
1328         return (protocol == IPPROTO_IP || protocol == IPPROTO_UDP);
1331 static inline u16 socket_type_to_security_class(int family, int type, int protocol)
1333         int extsockclass = selinux_policycap_extsockclass();
1335         switch (family) {
1336         case PF_UNIX:
1337                 switch (type) {
1338                 case SOCK_STREAM:
1339                 case SOCK_SEQPACKET:
1340                         return SECCLASS_UNIX_STREAM_SOCKET;
1341                 case SOCK_DGRAM:
1342                 case SOCK_RAW:
1343                         return SECCLASS_UNIX_DGRAM_SOCKET;
1344                 }
1345                 break;
1346         case PF_INET:
1347         case PF_INET6:
1348                 switch (type) {
1349                 case SOCK_STREAM:
1350                 case SOCK_SEQPACKET:
1351                         if (default_protocol_stream(protocol))
1352                                 return SECCLASS_TCP_SOCKET;
1353                         else if (extsockclass && protocol == IPPROTO_SCTP)
1354                                 return SECCLASS_SCTP_SOCKET;
1355                         else
1356                                 return SECCLASS_RAWIP_SOCKET;
1357                 case SOCK_DGRAM:
1358                         if (default_protocol_dgram(protocol))
1359                                 return SECCLASS_UDP_SOCKET;
1360                         else if (extsockclass && (protocol == IPPROTO_ICMP ||
1361                                                   protocol == IPPROTO_ICMPV6))
1362                                 return SECCLASS_ICMP_SOCKET;
1363                         else
1364                                 return SECCLASS_RAWIP_SOCKET;
1365                 case SOCK_DCCP:
1366                         return SECCLASS_DCCP_SOCKET;
1367                 default:
1368                         return SECCLASS_RAWIP_SOCKET;
1369                 }
1370                 break;
1371         case PF_NETLINK:
1372                 switch (protocol) {
1373                 case NETLINK_ROUTE:
1374                         return SECCLASS_NETLINK_ROUTE_SOCKET;
1375                 case NETLINK_SOCK_DIAG:
1376                         return SECCLASS_NETLINK_TCPDIAG_SOCKET;
1377                 case NETLINK_NFLOG:
1378                         return SECCLASS_NETLINK_NFLOG_SOCKET;
1379                 case NETLINK_XFRM:
1380                         return SECCLASS_NETLINK_XFRM_SOCKET;
1381                 case NETLINK_SELINUX:
1382                         return SECCLASS_NETLINK_SELINUX_SOCKET;
1383                 case NETLINK_ISCSI:
1384                         return SECCLASS_NETLINK_ISCSI_SOCKET;
1385                 case NETLINK_AUDIT:
1386                         return SECCLASS_NETLINK_AUDIT_SOCKET;
1387                 case NETLINK_FIB_LOOKUP:
1388                         return SECCLASS_NETLINK_FIB_LOOKUP_SOCKET;
1389                 case NETLINK_CONNECTOR:
1390                         return SECCLASS_NETLINK_CONNECTOR_SOCKET;
1391                 case NETLINK_NETFILTER:
1392                         return SECCLASS_NETLINK_NETFILTER_SOCKET;
1393                 case NETLINK_DNRTMSG:
1394                         return SECCLASS_NETLINK_DNRT_SOCKET;
1395                 case NETLINK_KOBJECT_UEVENT:
1396                         return SECCLASS_NETLINK_KOBJECT_UEVENT_SOCKET;
1397                 case NETLINK_GENERIC:
1398                         return SECCLASS_NETLINK_GENERIC_SOCKET;
1399                 case NETLINK_SCSITRANSPORT:
1400                         return SECCLASS_NETLINK_SCSITRANSPORT_SOCKET;
1401                 case NETLINK_RDMA:
1402                         return SECCLASS_NETLINK_RDMA_SOCKET;
1403                 case NETLINK_CRYPTO:
1404                         return SECCLASS_NETLINK_CRYPTO_SOCKET;
1405                 default:
1406                         return SECCLASS_NETLINK_SOCKET;
1407                 }
1408         case PF_PACKET:
1409                 return SECCLASS_PACKET_SOCKET;
1410         case PF_KEY:
1411                 return SECCLASS_KEY_SOCKET;
1412         case PF_APPLETALK:
1413                 return SECCLASS_APPLETALK_SOCKET;
1414         }
1416         if (extsockclass) {
1417                 switch (family) {
1418                 case PF_AX25:
1419                         return SECCLASS_AX25_SOCKET;
1420                 case PF_IPX:
1421                         return SECCLASS_IPX_SOCKET;
1422                 case PF_NETROM:
1423                         return SECCLASS_NETROM_SOCKET;
1424                 case PF_ATMPVC:
1425                         return SECCLASS_ATMPVC_SOCKET;
1426                 case PF_X25:
1427                         return SECCLASS_X25_SOCKET;
1428                 case PF_ROSE:
1429                         return SECCLASS_ROSE_SOCKET;
1430                 case PF_DECnet:
1431                         return SECCLASS_DECNET_SOCKET;
1432                 case PF_ATMSVC:
1433                         return SECCLASS_ATMSVC_SOCKET;
1434                 case PF_RDS:
1435                         return SECCLASS_RDS_SOCKET;
1436                 case PF_IRDA:
1437                         return SECCLASS_IRDA_SOCKET;
1438                 case PF_PPPOX:
1439                         return SECCLASS_PPPOX_SOCKET;
1440                 case PF_LLC:
1441                         return SECCLASS_LLC_SOCKET;
1442                 case PF_CAN:
1443                         return SECCLASS_CAN_SOCKET;
1444                 case PF_TIPC:
1445                         return SECCLASS_TIPC_SOCKET;
1446                 case PF_BLUETOOTH:
1447                         return SECCLASS_BLUETOOTH_SOCKET;
1448                 case PF_IUCV:
1449                         return SECCLASS_IUCV_SOCKET;
1450                 case PF_RXRPC:
1451                         return SECCLASS_RXRPC_SOCKET;
1452                 case PF_ISDN:
1453                         return SECCLASS_ISDN_SOCKET;
1454                 case PF_PHONET:
1455                         return SECCLASS_PHONET_SOCKET;
1456                 case PF_IEEE802154:
1457                         return SECCLASS_IEEE802154_SOCKET;
1458                 case PF_CAIF:
1459                         return SECCLASS_CAIF_SOCKET;
1460                 case PF_ALG:
1461                         return SECCLASS_ALG_SOCKET;
1462                 case PF_NFC:
1463                         return SECCLASS_NFC_SOCKET;
1464                 case PF_VSOCK:
1465                         return SECCLASS_VSOCK_SOCKET;
1466                 case PF_KCM:
1467                         return SECCLASS_KCM_SOCKET;
1468                 case PF_QIPCRTR:
1469                         return SECCLASS_QIPCRTR_SOCKET;
1470                 case PF_SMC:
1471                         return SECCLASS_SMC_SOCKET;
1472                 case PF_XDP:
1473                         return SECCLASS_XDP_SOCKET;
1474 #if PF_MAX > 45
1475 #error New address family defined, please update this function.
1476 #endif
1477                 }
1478         }
1480         return SECCLASS_SOCKET;
1483 static int selinux_genfs_get_sid(struct dentry *dentry,
1484                                  u16 tclass,
1485                                  u16 flags,
1486                                  u32 *sid)
1488         int rc;
1489         struct super_block *sb = dentry->d_sb;
1490         char *buffer, *path;
1492         buffer = (char *)__get_free_page(GFP_KERNEL);
1493         if (!buffer)
1494                 return -ENOMEM;
1496         path = dentry_path_raw(dentry, buffer, PAGE_SIZE);
1497         if (IS_ERR(path))
1498                 rc = PTR_ERR(path);
1499         else {
1500                 if (flags & SE_SBPROC) {
1501                         /* each process gets a /proc/PID/ entry. Strip off the
1502                          * PID part to get a valid selinux labeling.
1503                          * e.g. /proc/1/net/rpc/nfs -> /net/rpc/nfs */
1504                         while (path[1] >= '0' && path[1] <= '9') {
1505                                 path[1] = '/';
1506                                 path++;
1507                         }
1508                 }
1509                 rc = security_genfs_sid(&selinux_state, sb->s_type->name,
1510                                         path, tclass, sid);
1511         }
1512         free_page((unsigned long)buffer);
1513         return rc;
1516 /* The inode's security attributes must be initialized before first use. */
1517 static int inode_doinit_with_dentry(struct inode *inode, struct dentry *opt_dentry)
1519         struct superblock_security_struct *sbsec = NULL;
1520         struct inode_security_struct *isec = inode->i_security;
1521         u32 task_sid, sid = 0;
1522         u16 sclass;
1523         struct dentry *dentry;
1524 #define INITCONTEXTLEN 255
1525         char *context = NULL;
1526         unsigned len = 0;
1527         int rc = 0;
1529         if (isec->initialized == LABEL_INITIALIZED)
1530                 return 0;
1532         spin_lock(&isec->lock);
1533         if (isec->initialized == LABEL_INITIALIZED)
1534                 goto out_unlock;
1536         if (isec->sclass == SECCLASS_FILE)
1537                 isec->sclass = inode_mode_to_security_class(inode->i_mode);
1539         sbsec = inode->i_sb->s_security;
1540         if (!(sbsec->flags & SE_SBINITIALIZED)) {
1541                 /* Defer initialization until selinux_complete_init,
1542                    after the initial policy is loaded and the security
1543                    server is ready to handle calls. */
1544                 spin_lock(&sbsec->isec_lock);
1545                 if (list_empty(&isec->list))
1546                         list_add(&isec->list, &sbsec->isec_head);
1547                 spin_unlock(&sbsec->isec_lock);
1548                 goto out_unlock;
1549         }
1551         sclass = isec->sclass;
1552         task_sid = isec->task_sid;
1553         sid = isec->sid;
1554         isec->initialized = LABEL_PENDING;
1555         spin_unlock(&isec->lock);
1557         switch (sbsec->behavior) {
1558         case SECURITY_FS_USE_NATIVE:
1559                 break;
1560         case SECURITY_FS_USE_XATTR:
1561                 if (!(inode->i_opflags & IOP_XATTR)) {
1562                         sid = sbsec->def_sid;
1563                         break;
1564                 }
1565                 /* Need a dentry, since the xattr API requires one.
1566                    Life would be simpler if we could just pass the inode. */
1567                 if (opt_dentry) {
1568                         /* Called from d_instantiate or d_splice_alias. */
1569                         dentry = dget(opt_dentry);
1570                 } else {
1571                         /*
1572                          * Called from selinux_complete_init, try to find a dentry.
1573                          * Some filesystems really want a connected one, so try
1574                          * that first.  We could split SECURITY_FS_USE_XATTR in
1575                          * two, depending upon that...
1576                          */
1577                         dentry = d_find_alias(inode);
1578                         if (!dentry)
1579                                 dentry = d_find_any_alias(inode);
1580                 }
1581                 if (!dentry) {
1582                         /*
1583                          * this is can be hit on boot when a file is accessed
1584                          * before the policy is loaded.  When we load policy we
1585                          * may find inodes that have no dentry on the
1586                          * sbsec->isec_head list.  No reason to complain as these
1587                          * will get fixed up the next time we go through
1588                          * inode_doinit with a dentry, before these inodes could
1589                          * be used again by userspace.
1590                          */
1591                         goto out;
1592                 }
1594                 len = INITCONTEXTLEN;
1595                 context = kmalloc(len+1, GFP_NOFS);
1596                 if (!context) {
1597                         rc = -ENOMEM;
1598                         dput(dentry);
1599                         goto out;
1600                 }
1601                 context[len] = '\0';
1602                 rc = __vfs_getxattr(dentry, inode, XATTR_NAME_SELINUX, context, len);
1603                 if (rc == -ERANGE) {
1604                         kfree(context);
1606                         /* Need a larger buffer.  Query for the right size. */
1607                         rc = __vfs_getxattr(dentry, inode, XATTR_NAME_SELINUX, NULL, 0);
1608                         if (rc < 0) {
1609                                 dput(dentry);
1610                                 goto out;
1611                         }
1612                         len = rc;
1613                         context = kmalloc(len+1, GFP_NOFS);
1614                         if (!context) {
1615                                 rc = -ENOMEM;
1616                                 dput(dentry);
1617                                 goto out;
1618                         }
1619                         context[len] = '\0';
1620                         rc = __vfs_getxattr(dentry, inode, XATTR_NAME_SELINUX, context, len);
1621                 }
1622                 dput(dentry);
1623                 if (rc < 0) {
1624                         if (rc != -ENODATA) {
1625                                 pr_warn("SELinux: %s:  getxattr returned "
1626                                        "%d for dev=%s ino=%ld\n", __func__,
1627                                        -rc, inode->i_sb->s_id, inode->i_ino);
1628                                 kfree(context);
1629                                 goto out;
1630                         }
1631                         /* Map ENODATA to the default file SID */
1632                         sid = sbsec->def_sid;
1633                         rc = 0;
1634                 } else {
1635                         rc = security_context_to_sid_default(&selinux_state,
1636                                                              context, rc, &sid,
1637                                                              sbsec->def_sid,
1638                                                              GFP_NOFS);
1639                         if (rc) {
1640                                 char *dev = inode->i_sb->s_id;
1641                                 unsigned long ino = inode->i_ino;
1643                                 if (rc == -EINVAL) {
1644                                         if (printk_ratelimit())
1645                                                 pr_notice("SELinux: inode=%lu on dev=%s was found to have an invalid "
1646                                                         "context=%s.  This indicates you may need to relabel the inode or the "
1647                                                         "filesystem in question.\n", ino, dev, context);
1648                                 } else {
1649                                         pr_warn("SELinux: %s:  context_to_sid(%s) "
1650                                                "returned %d for dev=%s ino=%ld\n",
1651                                                __func__, context, -rc, dev, ino);
1652                                 }
1653                                 kfree(context);
1654                                 /* Leave with the unlabeled SID */
1655                                 rc = 0;
1656                                 break;
1657                         }
1658                 }
1659                 kfree(context);
1660                 break;
1661         case SECURITY_FS_USE_TASK:
1662                 sid = task_sid;
1663                 break;
1664         case SECURITY_FS_USE_TRANS:
1665                 /* Default to the fs SID. */
1666                 sid = sbsec->sid;
1668                 /* Try to obtain a transition SID. */
1669                 rc = security_transition_sid(&selinux_state, task_sid, sid,
1670                                              sclass, NULL, &sid);
1671                 if (rc)
1672                         goto out;
1673                 break;
1674         case SECURITY_FS_USE_MNTPOINT:
1675                 sid = sbsec->mntpoint_sid;
1676                 break;
1677         default:
1678                 /* Default to the fs superblock SID. */
1679                 sid = sbsec->sid;
1681                 if ((sbsec->flags & SE_SBGENFS) && !S_ISLNK(inode->i_mode)) {
1682                         /* We must have a dentry to determine the label on
1683                          * procfs inodes */
1684                         if (opt_dentry) {
1685                                 /* Called from d_instantiate or
1686                                  * d_splice_alias. */
1687                                 dentry = dget(opt_dentry);
1688                         } else {
1689                                 /* Called from selinux_complete_init, try to
1690                                  * find a dentry.  Some filesystems really want
1691                                  * a connected one, so try that first.
1692                                  */
1693                                 dentry = d_find_alias(inode);
1694                                 if (!dentry)
1695                                         dentry = d_find_any_alias(inode);
1696                         }
1697                         /*
1698                          * This can be hit on boot when a file is accessed
1699                          * before the policy is loaded.  When we load policy we
1700                          * may find inodes that have no dentry on the
1701                          * sbsec->isec_head list.  No reason to complain as
1702                          * these will get fixed up the next time we go through
1703                          * inode_doinit() with a dentry, before these inodes
1704                          * could be used again by userspace.
1705                          */
1706                         if (!dentry)
1707                                 goto out;
1708                         rc = selinux_genfs_get_sid(dentry, sclass,
1709                                                    sbsec->flags, &sid);
1710                         dput(dentry);
1711                         if (rc)
1712                                 goto out;
1713                 }
1714                 break;
1715         }
1717 out:
1718         spin_lock(&isec->lock);
1719         if (isec->initialized == LABEL_PENDING) {
1720                 if (!sid || rc) {
1721                         isec->initialized = LABEL_INVALID;
1722                         goto out_unlock;
1723                 }
1725                 isec->initialized = LABEL_INITIALIZED;
1726                 isec->sid = sid;
1727         }
1729 out_unlock:
1730         spin_unlock(&isec->lock);
1731         return rc;
1734 /* Convert a Linux signal to an access vector. */
1735 static inline u32 signal_to_av(int sig)
1737         u32 perm = 0;
1739         switch (sig) {
1740         case SIGCHLD:
1741                 /* Commonly granted from child to parent. */
1742                 perm = PROCESS__SIGCHLD;
1743                 break;
1744         case SIGKILL:
1745                 /* Cannot be caught or ignored */
1746                 perm = PROCESS__SIGKILL;
1747                 break;
1748         case SIGSTOP:
1749                 /* Cannot be caught or ignored */
1750                 perm = PROCESS__SIGSTOP;
1751                 break;
1752         default:
1753                 /* All other signals. */
1754                 perm = PROCESS__SIGNAL;
1755                 break;
1756         }
1758         return perm;
1761 #if CAP_LAST_CAP > 63
1762 #error Fix SELinux to handle capabilities > 63.
1763 #endif
1765 /* Check whether a task is allowed to use a capability. */
1766 static int cred_has_capability(const struct cred *cred,
1767                                int cap, int audit, bool initns)
1769         struct common_audit_data ad;
1770         struct av_decision avd;
1771         u16 sclass;
1772         u32 sid = cred_sid(cred);
1773         u32 av = CAP_TO_MASK(cap);
1774         int rc;
1776         ad.type = LSM_AUDIT_DATA_CAP;
1777         ad.u.cap = cap;
1779         switch (CAP_TO_INDEX(cap)) {
1780         case 0:
1781                 sclass = initns ? SECCLASS_CAPABILITY : SECCLASS_CAP_USERNS;
1782                 break;
1783         case 1:
1784                 sclass = initns ? SECCLASS_CAPABILITY2 : SECCLASS_CAP2_USERNS;
1785                 break;
1786         default:
1787                 pr_err("SELinux:  out of range capability %d\n", cap);
1788                 BUG();
1789                 return -EINVAL;
1790         }
1792         rc = avc_has_perm_noaudit(&selinux_state,
1793                                   sid, sid, sclass, av, 0, &avd);
1794         if (audit == SECURITY_CAP_AUDIT) {
1795                 int rc2 = avc_audit(&selinux_state,
1796                                     sid, sid, sclass, av, &avd, rc, &ad, 0);
1797                 if (rc2)
1798                         return rc2;
1799         }
1800         return rc;
1803 /* Check whether a task has a particular permission to an inode.
1804    The 'adp' parameter is optional and allows other audit
1805    data to be passed (e.g. the dentry). */
1806 static int inode_has_perm(const struct cred *cred,
1807                           struct inode *inode,
1808                           u32 perms,
1809                           struct common_audit_data *adp)
1811         struct inode_security_struct *isec;
1812         u32 sid;
1814         validate_creds(cred);
1816         if (unlikely(IS_PRIVATE(inode)))
1817                 return 0;
1819         sid = cred_sid(cred);
1820         isec = inode->i_security;
1822         return avc_has_perm(&selinux_state,
1823                             sid, isec->sid, isec->sclass, perms, adp);
1826 /* Same as inode_has_perm, but pass explicit audit data containing
1827    the dentry to help the auditing code to more easily generate the
1828    pathname if needed. */
1829 static inline int dentry_has_perm(const struct cred *cred,
1830                                   struct dentry *dentry,
1831                                   u32 av)
1833         struct inode *inode = d_backing_inode(dentry);
1834         struct common_audit_data ad;
1836         ad.type = LSM_AUDIT_DATA_DENTRY;
1837         ad.u.dentry = dentry;
1838         __inode_security_revalidate(inode, dentry, true);
1839         return inode_has_perm(cred, inode, av, &ad);
1842 /* Same as inode_has_perm, but pass explicit audit data containing
1843    the path to help the auditing code to more easily generate the
1844    pathname if needed. */
1845 static inline int path_has_perm(const struct cred *cred,
1846                                 const struct path *path,
1847                                 u32 av)
1849         struct inode *inode = d_backing_inode(path->dentry);
1850         struct common_audit_data ad;
1852         ad.type = LSM_AUDIT_DATA_PATH;
1853         ad.u.path = *path;
1854         __inode_security_revalidate(inode, path->dentry, true);
1855         return inode_has_perm(cred, inode, av, &ad);
1858 /* Same as path_has_perm, but uses the inode from the file struct. */
1859 static inline int file_path_has_perm(const struct cred *cred,
1860                                      struct file *file,
1861                                      u32 av)
1863         struct common_audit_data ad;
1865         ad.type = LSM_AUDIT_DATA_FILE;
1866         ad.u.file = file;
1867         return inode_has_perm(cred, file_inode(file), av, &ad);
1870 #ifdef CONFIG_BPF_SYSCALL
1871 static int bpf_fd_pass(struct file *file, u32 sid);
1872 #endif
1874 /* Check whether a task can use an open file descriptor to
1875    access an inode in a given way.  Check access to the
1876    descriptor itself, and then use dentry_has_perm to
1877    check a particular permission to the file.
1878    Access to the descriptor is implicitly granted if it
1879    has the same SID as the process.  If av is zero, then
1880    access to the file is not checked, e.g. for cases
1881    where only the descriptor is affected like seek. */
1882 static int file_has_perm(const struct cred *cred,
1883                          struct file *file,
1884                          u32 av)
1886         struct file_security_struct *fsec = file->f_security;
1887         struct inode *inode = file_inode(file);
1888         struct common_audit_data ad;
1889         u32 sid = cred_sid(cred);
1890         int rc;
1892         ad.type = LSM_AUDIT_DATA_FILE;
1893         ad.u.file = file;
1895         if (sid != fsec->sid) {
1896                 rc = avc_has_perm(&selinux_state,
1897                                   sid, fsec->sid,
1898                                   SECCLASS_FD,
1899                                   FD__USE,
1900                                   &ad);
1901                 if (rc)
1902                         goto out;
1903         }
1905 #ifdef CONFIG_BPF_SYSCALL
1906         rc = bpf_fd_pass(file, cred_sid(cred));
1907         if (rc)
1908                 return rc;
1909 #endif
1911         /* av is zero if only checking access to the descriptor. */
1912         rc = 0;
1913         if (av)
1914                 rc = inode_has_perm(cred, inode, av, &ad);
1916 out:
1917         return rc;
1920 /*
1921  * Determine the label for an inode that might be unioned.
1922  */
1923 static int
1924 selinux_determine_inode_label(const struct task_security_struct *tsec,
1925                                  struct inode *dir,
1926                                  const struct qstr *name, u16 tclass,
1927                                  u32 *_new_isid)
1929         const struct superblock_security_struct *sbsec = dir->i_sb->s_security;
1931         if ((sbsec->flags & SE_SBINITIALIZED) &&
1932             (sbsec->behavior == SECURITY_FS_USE_MNTPOINT)) {
1933                 *_new_isid = sbsec->mntpoint_sid;
1934         } else if ((sbsec->flags & SBLABEL_MNT) &&
1935                    tsec->create_sid) {
1936                 *_new_isid = tsec->create_sid;
1937         } else {
1938                 const struct inode_security_struct *dsec = inode_security(dir);
1939                 return security_transition_sid(&selinux_state, tsec->sid,
1940                                                dsec->sid, tclass,
1941                                                name, _new_isid);
1942         }
1944         return 0;
1947 /* Check whether a task can create a file. */
1948 static int may_create(struct inode *dir,
1949                       struct dentry *dentry,
1950                       u16 tclass)
1952         const struct task_security_struct *tsec = current_security();
1953         struct inode_security_struct *dsec;
1954         struct superblock_security_struct *sbsec;
1955         u32 sid, newsid;
1956         struct common_audit_data ad;
1957         int rc;
1959         dsec = inode_security(dir);
1960         sbsec = dir->i_sb->s_security;
1962         sid = tsec->sid;
1964         ad.type = LSM_AUDIT_DATA_DENTRY;
1965         ad.u.dentry = dentry;
1967         rc = avc_has_perm(&selinux_state,
1968                           sid, dsec->sid, SECCLASS_DIR,
1969                           DIR__ADD_NAME | DIR__SEARCH,
1970                           &ad);
1971         if (rc)
1972                 return rc;
1974         rc = selinux_determine_inode_label(current_security(), dir,
1975                                            &dentry->d_name, tclass, &newsid);
1976         if (rc)
1977                 return rc;
1979         rc = avc_has_perm(&selinux_state,
1980                           sid, newsid, tclass, FILE__CREATE, &ad);
1981         if (rc)
1982                 return rc;
1984         return avc_has_perm(&selinux_state,
1985                             newsid, sbsec->sid,
1986                             SECCLASS_FILESYSTEM,
1987                             FILESYSTEM__ASSOCIATE, &ad);
1990 #define MAY_LINK        0
1991 #define MAY_UNLINK      1
1992 #define MAY_RMDIR       2
1994 /* Check whether a task can link, unlink, or rmdir a file/directory. */
1995 static int may_link(struct inode *dir,
1996                     struct dentry *dentry,
1997                     int kind)
2000         struct inode_security_struct *dsec, *isec;
2001         struct common_audit_data ad;
2002         u32 sid = current_sid();
2003         u32 av;
2004         int rc;
2006         dsec = inode_security(dir);
2007         isec = backing_inode_security(dentry);
2009         ad.type = LSM_AUDIT_DATA_DENTRY;
2010         ad.u.dentry = dentry;
2012         av = DIR__SEARCH;
2013         av |= (kind ? DIR__REMOVE_NAME : DIR__ADD_NAME);
2014         rc = avc_has_perm(&selinux_state,
2015                           sid, dsec->sid, SECCLASS_DIR, av, &ad);
2016         if (rc)
2017                 return rc;
2019         switch (kind) {
2020         case MAY_LINK:
2021                 av = FILE__LINK;
2022                 break;
2023         case MAY_UNLINK:
2024                 av = FILE__UNLINK;
2025                 break;
2026         case MAY_RMDIR:
2027                 av = DIR__RMDIR;
2028                 break;
2029         default:
2030                 pr_warn("SELinux: %s:  unrecognized kind %d\n",
2031                         __func__, kind);
2032                 return 0;
2033         }
2035         rc = avc_has_perm(&selinux_state,
2036                           sid, isec->sid, isec->sclass, av, &ad);
2037         return rc;
2040 static inline int may_rename(struct inode *old_dir,
2041                              struct dentry *old_dentry,
2042                              struct inode *new_dir,
2043                              struct dentry *new_dentry)
2045         struct inode_security_struct *old_dsec, *new_dsec, *old_isec, *new_isec;
2046         struct common_audit_data ad;
2047         u32 sid = current_sid();
2048         u32 av;
2049         int old_is_dir, new_is_dir;
2050         int rc;
2052         old_dsec = inode_security(old_dir);
2053         old_isec = backing_inode_security(old_dentry);
2054         old_is_dir = d_is_dir(old_dentry);
2055         new_dsec = inode_security(new_dir);
2057         ad.type = LSM_AUDIT_DATA_DENTRY;
2059         ad.u.dentry = old_dentry;
2060         rc = avc_has_perm(&selinux_state,
2061                           sid, old_dsec->sid, SECCLASS_DIR,
2062                           DIR__REMOVE_NAME | DIR__SEARCH, &ad);
2063         if (rc)
2064                 return rc;
2065         rc = avc_has_perm(&selinux_state,
2066                           sid, old_isec->sid,
2067                           old_isec->sclass, FILE__RENAME, &ad);
2068         if (rc)
2069                 return rc;
2070         if (old_is_dir && new_dir != old_dir) {
2071                 rc = avc_has_perm(&selinux_state,
2072                                   sid, old_isec->sid,
2073                                   old_isec->sclass, DIR__REPARENT, &ad);
2074                 if (rc)
2075                         return rc;
2076         }
2078         ad.u.dentry = new_dentry;
2079         av = DIR__ADD_NAME | DIR__SEARCH;
2080         if (d_is_positive(new_dentry))
2081                 av |= DIR__REMOVE_NAME;
2082         rc = avc_has_perm(&selinux_state,
2083                           sid, new_dsec->sid, SECCLASS_DIR, av, &ad);
2084         if (rc)
2085                 return rc;
2086         if (d_is_positive(new_dentry)) {
2087                 new_isec = backing_inode_security(new_dentry);
2088                 new_is_dir = d_is_dir(new_dentry);
2089                 rc = avc_has_perm(&selinux_state,
2090                                   sid, new_isec->sid,
2091                                   new_isec->sclass,
2092                                   (new_is_dir ? DIR__RMDIR : FILE__UNLINK), &ad);
2093                 if (rc)
2094                         return rc;
2095         }
2097         return 0;
2100 /* Check whether a task can perform a filesystem operation. */
2101 static int superblock_has_perm(const struct cred *cred,
2102                                struct super_block *sb,
2103                                u32 perms,
2104                                struct common_audit_data *ad)
2106         struct superblock_security_struct *sbsec;
2107         u32 sid = cred_sid(cred);
2109         sbsec = sb->s_security;
2110         return avc_has_perm(&selinux_state,
2111                             sid, sbsec->sid, SECCLASS_FILESYSTEM, perms, ad);
2114 /* Convert a Linux mode and permission mask to an access vector. */
2115 static inline u32 file_mask_to_av(int mode, int mask)
2117         u32 av = 0;
2119         if (!S_ISDIR(mode)) {
2120                 if (mask & MAY_EXEC)
2121                         av |= FILE__EXECUTE;
2122                 if (mask & MAY_READ)
2123                         av |= FILE__READ;
2125                 if (mask & MAY_APPEND)
2126                         av |= FILE__APPEND;
2127                 else if (mask & MAY_WRITE)
2128                         av |= FILE__WRITE;
2130         } else {
2131                 if (mask & MAY_EXEC)
2132                         av |= DIR__SEARCH;
2133                 if (mask & MAY_WRITE)
2134                         av |= DIR__WRITE;
2135                 if (mask & MAY_READ)
2136                         av |= DIR__READ;
2137         }
2139         return av;
2142 /* Convert a Linux file to an access vector. */
2143 static inline u32 file_to_av(struct file *file)
2145         u32 av = 0;
2147         if (file->f_mode & FMODE_READ)
2148                 av |= FILE__READ;
2149         if (file->f_mode & FMODE_WRITE) {
2150                 if (file->f_flags & O_APPEND)
2151                         av |= FILE__APPEND;
2152                 else
2153                         av |= FILE__WRITE;
2154         }
2155         if (!av) {
2156                 /*
2157                  * Special file opened with flags 3 for ioctl-only use.
2158                  */
2159                 av = FILE__IOCTL;
2160         }
2162         return av;
2165 /*
2166  * Convert a file to an access vector and include the correct open
2167  * open permission.
2168  */
2169 static inline u32 open_file_to_av(struct file *file)
2171         u32 av = file_to_av(file);
2172         struct inode *inode = file_inode(file);
2174         if (selinux_policycap_openperm() &&
2175             inode->i_sb->s_magic != SOCKFS_MAGIC)
2176                 av |= FILE__OPEN;
2178         return av;
2181 /* Hook functions begin here. */
2183 static int selinux_binder_set_context_mgr(struct task_struct *mgr)
2185         u32 mysid = current_sid();
2186         u32 mgrsid = task_sid(mgr);
2188         return avc_has_perm(&selinux_state,
2189                             mysid, mgrsid, SECCLASS_BINDER,
2190                             BINDER__SET_CONTEXT_MGR, NULL);
2193 static int selinux_binder_transaction(struct task_struct *from,
2194                                       struct task_struct *to)
2196         u32 mysid = current_sid();
2197         u32 fromsid = task_sid(from);
2198         u32 tosid = task_sid(to);
2199         int rc;
2201         if (mysid != fromsid) {
2202                 rc = avc_has_perm(&selinux_state,
2203                                   mysid, fromsid, SECCLASS_BINDER,
2204                                   BINDER__IMPERSONATE, NULL);
2205                 if (rc)
2206                         return rc;
2207         }
2209         return avc_has_perm(&selinux_state,
2210                             fromsid, tosid, SECCLASS_BINDER, BINDER__CALL,
2211                             NULL);
2214 static int selinux_binder_transfer_binder(struct task_struct *from,
2215                                           struct task_struct *to)
2217         u32 fromsid = task_sid(from);
2218         u32 tosid = task_sid(to);
2220         return avc_has_perm(&selinux_state,
2221                             fromsid, tosid, SECCLASS_BINDER, BINDER__TRANSFER,
2222                             NULL);
2225 static int selinux_binder_transfer_file(struct task_struct *from,
2226                                         struct task_struct *to,
2227                                         struct file *file)
2229         u32 sid = task_sid(to);
2230         struct file_security_struct *fsec = file->f_security;
2231         struct dentry *dentry = file->f_path.dentry;
2232         struct inode_security_struct *isec;
2233         struct common_audit_data ad;
2234         int rc;
2236         ad.type = LSM_AUDIT_DATA_PATH;
2237         ad.u.path = file->f_path;
2239         if (sid != fsec->sid) {
2240                 rc = avc_has_perm(&selinux_state,
2241                                   sid, fsec->sid,
2242                                   SECCLASS_FD,
2243                                   FD__USE,
2244                                   &ad);
2245                 if (rc)
2246                         return rc;
2247         }
2249 #ifdef CONFIG_BPF_SYSCALL
2250         rc = bpf_fd_pass(file, sid);
2251         if (rc)
2252                 return rc;
2253 #endif
2255         if (unlikely(IS_PRIVATE(d_backing_inode(dentry))))
2256                 return 0;
2258         isec = backing_inode_security(dentry);
2259         return avc_has_perm(&selinux_state,
2260                             sid, isec->sid, isec->sclass, file_to_av(file),
2261                             &ad);
2264 static int selinux_ptrace_access_check(struct task_struct *child,
2265                                      unsigned int mode)
2267         u32 sid = current_sid();
2268         u32 csid = task_sid(child);
2270         if (mode & PTRACE_MODE_READ)
2271                 return avc_has_perm(&selinux_state,
2272                                     sid, csid, SECCLASS_FILE, FILE__READ, NULL);
2274         return avc_has_perm(&selinux_state,
2275                             sid, csid, SECCLASS_PROCESS, PROCESS__PTRACE, NULL);
2278 static int selinux_ptrace_traceme(struct task_struct *parent)
2280         return avc_has_perm(&selinux_state,
2281                             task_sid(parent), current_sid(), SECCLASS_PROCESS,
2282                             PROCESS__PTRACE, NULL);
2285 static int selinux_capget(struct task_struct *target, kernel_cap_t *effective,
2286                           kernel_cap_t *inheritable, kernel_cap_t *permitted)
2288         return avc_has_perm(&selinux_state,
2289                             current_sid(), task_sid(target), SECCLASS_PROCESS,
2290                             PROCESS__GETCAP, NULL);
2293 static int selinux_capset(struct cred *new, const struct cred *old,
2294                           const kernel_cap_t *effective,
2295                           const kernel_cap_t *inheritable,
2296                           const kernel_cap_t *permitted)
2298         return avc_has_perm(&selinux_state,
2299                             cred_sid(old), cred_sid(new), SECCLASS_PROCESS,
2300                             PROCESS__SETCAP, NULL);
2303 /*
2304  * (This comment used to live with the selinux_task_setuid hook,
2305  * which was removed).
2306  *
2307  * Since setuid only affects the current process, and since the SELinux
2308  * controls are not based on the Linux identity attributes, SELinux does not
2309  * need to control this operation.  However, SELinux does control the use of
2310  * the CAP_SETUID and CAP_SETGID capabilities using the capable hook.
2311  */
2313 static int selinux_capable(const struct cred *cred, struct user_namespace *ns,
2314                            int cap, int audit)
2316         return cred_has_capability(cred, cap, audit, ns == &init_user_ns);
2319 static int selinux_quotactl(int cmds, int type, int id, struct super_block *sb)
2321         const struct cred *cred = current_cred();
2322         int rc = 0;
2324         if (!sb)
2325                 return 0;
2327         switch (cmds) {
2328         case Q_SYNC:
2329         case Q_QUOTAON:
2330         case Q_QUOTAOFF:
2331         case Q_SETINFO:
2332         case Q_SETQUOTA:
2333                 rc = superblock_has_perm(cred, sb, FILESYSTEM__QUOTAMOD, NULL);
2334                 break;
2335         case Q_GETFMT:
2336         case Q_GETINFO:
2337         case Q_GETQUOTA:
2338                 rc = superblock_has_perm(cred, sb, FILESYSTEM__QUOTAGET, NULL);
2339                 break;
2340         default:
2341                 rc = 0;  /* let the kernel handle invalid cmds */
2342                 break;
2343         }
2344         return rc;
2347 static int selinux_quota_on(struct dentry *dentry)
2349         const struct cred *cred = current_cred();
2351         return dentry_has_perm(cred, dentry, FILE__QUOTAON);
2354 static int selinux_syslog(int type)
2356         switch (type) {
2357         case SYSLOG_ACTION_READ_ALL:    /* Read last kernel messages */
2358         case SYSLOG_ACTION_SIZE_BUFFER: /* Return size of the log buffer */
2359                 return avc_has_perm(&selinux_state,
2360                                     current_sid(), SECINITSID_KERNEL,
2361                                     SECCLASS_SYSTEM, SYSTEM__SYSLOG_READ, NULL);
2362         case SYSLOG_ACTION_CONSOLE_OFF: /* Disable logging to console */
2363         case SYSLOG_ACTION_CONSOLE_ON:  /* Enable logging to console */
2364         /* Set level of messages printed to console */
2365         case SYSLOG_ACTION_CONSOLE_LEVEL:
2366                 return avc_has_perm(&selinux_state,
2367                                     current_sid(), SECINITSID_KERNEL,
2368                                     SECCLASS_SYSTEM, SYSTEM__SYSLOG_CONSOLE,
2369                                     NULL);
2370         }
2371         /* All other syslog types */
2372         return avc_has_perm(&selinux_state,
2373                             current_sid(), SECINITSID_KERNEL,
2374                             SECCLASS_SYSTEM, SYSTEM__SYSLOG_MOD, NULL);
2377 /*
2378  * Check that a process has enough memory to allocate a new virtual
2379  * mapping. 0 means there is enough memory for the allocation to
2380  * succeed and -ENOMEM implies there is not.
2381  *
2382  * Do not audit the selinux permission check, as this is applied to all
2383  * processes that allocate mappings.
2384  */
2385 static int selinux_vm_enough_memory(struct mm_struct *mm, long pages)
2387         int rc, cap_sys_admin = 0;
2389         rc = cred_has_capability(current_cred(), CAP_SYS_ADMIN,
2390                                  SECURITY_CAP_NOAUDIT, true);
2391         if (rc == 0)
2392                 cap_sys_admin = 1;
2394         return cap_sys_admin;
2397 /* binprm security operations */
2399 static u32 ptrace_parent_sid(void)
2401         u32 sid = 0;
2402         struct task_struct *tracer;
2404         rcu_read_lock();
2405         tracer = ptrace_parent(current);
2406         if (tracer)
2407                 sid = task_sid(tracer);
2408         rcu_read_unlock();
2410         return sid;
2413 static int check_nnp_nosuid(const struct linux_binprm *bprm,
2414                             const struct task_security_struct *old_tsec,
2415                             const struct task_security_struct *new_tsec)
2417         int nnp = (bprm->unsafe & LSM_UNSAFE_NO_NEW_PRIVS);
2418         int nosuid = !mnt_may_suid(bprm->file->f_path.mnt);
2419         int rc;
2420         u32 av;
2422         if (!nnp && !nosuid)
2423                 return 0; /* neither NNP nor nosuid */
2425         if (new_tsec->sid == old_tsec->sid)
2426                 return 0; /* No change in credentials */
2428         /*
2429          * If the policy enables the nnp_nosuid_transition policy capability,
2430          * then we permit transitions under NNP or nosuid if the
2431          * policy allows the corresponding permission between
2432          * the old and new contexts.
2433          */
2434         if (selinux_policycap_nnp_nosuid_transition()) {
2435                 av = 0;
2436                 if (nnp)
2437                         av |= PROCESS2__NNP_TRANSITION;
2438                 if (nosuid)
2439                         av |= PROCESS2__NOSUID_TRANSITION;
2440                 rc = avc_has_perm(&selinux_state,
2441                                   old_tsec->sid, new_tsec->sid,
2442                                   SECCLASS_PROCESS2, av, NULL);
2443                 if (!rc)
2444                         return 0;
2445         }
2447         /*
2448          * We also permit NNP or nosuid transitions to bounded SIDs,
2449          * i.e. SIDs that are guaranteed to only be allowed a subset
2450          * of the permissions of the current SID.
2451          */
2452         rc = security_bounded_transition(&selinux_state, old_tsec->sid,
2453                                          new_tsec->sid);
2454         if (!rc)
2455                 return 0;
2457         /*
2458          * On failure, preserve the errno values for NNP vs nosuid.
2459          * NNP:  Operation not permitted for caller.
2460          * nosuid:  Permission denied to file.
2461          */
2462         if (nnp)
2463                 return -EPERM;
2464         return -EACCES;
2467 static int selinux_bprm_set_creds(struct linux_binprm *bprm)
2469         const struct task_security_struct *old_tsec;
2470         struct task_security_struct *new_tsec;
2471         struct inode_security_struct *isec;
2472         struct common_audit_data ad;
2473         struct inode *inode = file_inode(bprm->file);
2474         int rc;
2476         /* SELinux context only depends on initial program or script and not
2477          * the script interpreter */
2478         if (bprm->called_set_creds)
2479                 return 0;
2481         old_tsec = current_security();
2482         new_tsec = bprm->cred->security;
2483         isec = inode_security(inode);
2485         /* Default to the current task SID. */
2486         new_tsec->sid = old_tsec->sid;
2487         new_tsec->osid = old_tsec->sid;
2489         /* Reset fs, key, and sock SIDs on execve. */
2490         new_tsec->create_sid = 0;
2491         new_tsec->keycreate_sid = 0;
2492         new_tsec->sockcreate_sid = 0;
2494         if (old_tsec->exec_sid) {
2495                 new_tsec->sid = old_tsec->exec_sid;
2496                 /* Reset exec SID on execve. */
2497                 new_tsec->exec_sid = 0;
2499                 /* Fail on NNP or nosuid if not an allowed transition. */
2500                 rc = check_nnp_nosuid(bprm, old_tsec, new_tsec);
2501                 if (rc)
2502                         return rc;
2503         } else {
2504                 /* Check for a default transition on this program. */
2505                 rc = security_transition_sid(&selinux_state, old_tsec->sid,
2506                                              isec->sid, SECCLASS_PROCESS, NULL,
2507                                              &new_tsec->sid);
2508                 if (rc)
2509                         return rc;
2511                 /*
2512                  * Fallback to old SID on NNP or nosuid if not an allowed
2513                  * transition.
2514                  */
2515                 rc = check_nnp_nosuid(bprm, old_tsec, new_tsec);
2516                 if (rc)
2517                         new_tsec->sid = old_tsec->sid;
2518         }
2520         ad.type = LSM_AUDIT_DATA_FILE;
2521         ad.u.file = bprm->file;
2523         if (new_tsec->sid == old_tsec->sid) {
2524                 rc = avc_has_perm(&selinux_state,
2525                                   old_tsec->sid, isec->sid,
2526                                   SECCLASS_FILE, FILE__EXECUTE_NO_TRANS, &ad);
2527                 if (rc)
2528                         return rc;
2529         } else {
2530                 /* Check permissions for the transition. */
2531                 rc = avc_has_perm(&selinux_state,
2532                                   old_tsec->sid, new_tsec->sid,
2533                                   SECCLASS_PROCESS, PROCESS__TRANSITION, &ad);
2534                 if (rc)
2535                         return rc;
2537                 rc = avc_has_perm(&selinux_state,
2538                                   new_tsec->sid, isec->sid,
2539                                   SECCLASS_FILE, FILE__ENTRYPOINT, &ad);
2540                 if (rc)
2541                         return rc;
2543                 /* Check for shared state */
2544                 if (bprm->unsafe & LSM_UNSAFE_SHARE) {
2545                         rc = avc_has_perm(&selinux_state,
2546                                           old_tsec->sid, new_tsec->sid,
2547                                           SECCLASS_PROCESS, PROCESS__SHARE,
2548                                           NULL);
2549                         if (rc)
2550                                 return -EPERM;
2551                 }
2553                 /* Make sure that anyone attempting to ptrace over a task that
2554                  * changes its SID has the appropriate permit */
2555                 if (bprm->unsafe & LSM_UNSAFE_PTRACE) {
2556                         u32 ptsid = ptrace_parent_sid();
2557                         if (ptsid != 0) {
2558                                 rc = avc_has_perm(&selinux_state,
2559                                                   ptsid, new_tsec->sid,
2560                                                   SECCLASS_PROCESS,
2561                                                   PROCESS__PTRACE, NULL);
2562                                 if (rc)
2563                                         return -EPERM;
2564                         }
2565                 }
2567                 /* Clear any possibly unsafe personality bits on exec: */
2568                 bprm->per_clear |= PER_CLEAR_ON_SETID;
2570                 /* Enable secure mode for SIDs transitions unless
2571                    the noatsecure permission is granted between
2572                    the two SIDs, i.e. ahp returns 0. */
2573                 rc = avc_has_perm(&selinux_state,
2574                                   old_tsec->sid, new_tsec->sid,
2575                                   SECCLASS_PROCESS, PROCESS__NOATSECURE,
2576                                   NULL);
2577                 bprm->secureexec |= !!rc;
2578         }
2580         return 0;
2583 static int match_file(const void *p, struct file *file, unsigned fd)
2585         return file_has_perm(p, file, file_to_av(file)) ? fd + 1 : 0;
2588 /* Derived from fs/exec.c:flush_old_files. */
2589 static inline void flush_unauthorized_files(const struct cred *cred,
2590                                             struct files_struct *files)
2592         struct file *file, *devnull = NULL;
2593         struct tty_struct *tty;
2594         int drop_tty = 0;
2595         unsigned n;
2597         tty = get_current_tty();
2598         if (tty) {
2599                 spin_lock(&tty->files_lock);
2600                 if (!list_empty(&tty->tty_files)) {
2601                         struct tty_file_private *file_priv;
2603                         /* Revalidate access to controlling tty.
2604                            Use file_path_has_perm on the tty path directly
2605                            rather than using file_has_perm, as this particular
2606                            open file may belong to another process and we are
2607                            only interested in the inode-based check here. */
2608                         file_priv = list_first_entry(&tty->tty_files,
2609                                                 struct tty_file_private, list);
2610                         file = file_priv->file;
2611                         if (file_path_has_perm(cred, file, FILE__READ | FILE__WRITE))
2612                                 drop_tty = 1;
2613                 }
2614                 spin_unlock(&tty->files_lock);
2615                 tty_kref_put(tty);
2616         }
2617         /* Reset controlling tty. */
2618         if (drop_tty)
2619                 no_tty();
2621         /* Revalidate access to inherited open files. */
2622         n = iterate_fd(files, 0, match_file, cred);
2623         if (!n) /* none found? */
2624                 return;
2626         devnull = dentry_open(&selinux_null, O_RDWR, cred);
2627         if (IS_ERR(devnull))
2628                 devnull = NULL;
2629         /* replace all the matching ones with this */
2630         do {
2631                 replace_fd(n - 1, devnull, 0);
2632         } while ((n = iterate_fd(files, n, match_file, cred)) != 0);
2633         if (devnull)
2634                 fput(devnull);
2637 /*
2638  * Prepare a process for imminent new credential changes due to exec
2639  */
2640 static void selinux_bprm_committing_creds(struct linux_binprm *bprm)
2642         struct task_security_struct *new_tsec;
2643         struct rlimit *rlim, *initrlim;
2644         int rc, i;
2646         new_tsec = bprm->cred->security;
2647         if (new_tsec->sid == new_tsec->osid)
2648                 return;
2650         /* Close files for which the new task SID is not authorized. */
2651         flush_unauthorized_files(bprm->cred, current->files);
2653         /* Always clear parent death signal on SID transitions. */
2654         current->pdeath_signal = 0;
2656         /* Check whether the new SID can inherit resource limits from the old
2657          * SID.  If not, reset all soft limits to the lower of the current
2658          * task's hard limit and the init task's soft limit.
2659          *
2660          * Note that the setting of hard limits (even to lower them) can be
2661          * controlled by the setrlimit check.  The inclusion of the init task's
2662          * soft limit into the computation is to avoid resetting soft limits
2663          * higher than the default soft limit for cases where the default is
2664          * lower than the hard limit, e.g. RLIMIT_CORE or RLIMIT_STACK.
2665          */
2666         rc = avc_has_perm(&selinux_state,
2667                           new_tsec->osid, new_tsec->sid, SECCLASS_PROCESS,
2668                           PROCESS__RLIMITINH, NULL);
2669         if (rc) {
2670                 /* protect against do_prlimit() */
2671                 task_lock(current);
2672                 for (i = 0; i < RLIM_NLIMITS; i++) {
2673                         rlim = current->signal->rlim + i;
2674                         initrlim = init_task.signal->rlim + i;
2675                         rlim->rlim_cur = min(rlim->rlim_max, initrlim->rlim_cur);
2676                 }
2677                 task_unlock(current);
2678                 if (IS_ENABLED(CONFIG_POSIX_TIMERS))
2679                         update_rlimit_cpu(current, rlimit(RLIMIT_CPU));
2680         }
2683 /*
2684  * Clean up the process immediately after the installation of new credentials
2685  * due to exec
2686  */
2687 static void selinux_bprm_committed_creds(struct linux_binprm *bprm)
2689         const struct task_security_struct *tsec = current_security();
2690         struct itimerval itimer;
2691         u32 osid, sid;
2692         int rc, i;
2694         osid = tsec->osid;
2695         sid = tsec->sid;
2697         if (sid == osid)
2698                 return;
2700         /* Check whether the new SID can inherit signal state from the old SID.
2701          * If not, clear itimers to avoid subsequent signal generation and
2702          * flush and unblock signals.
2703          *
2704          * This must occur _after_ the task SID has been updated so that any
2705          * kill done after the flush will be checked against the new SID.
2706          */
2707         rc = avc_has_perm(&selinux_state,
2708                           osid, sid, SECCLASS_PROCESS, PROCESS__SIGINH, NULL);
2709         if (rc) {
2710                 if (IS_ENABLED(CONFIG_POSIX_TIMERS)) {
2711                         memset(&itimer, 0, sizeof itimer);
2712                         for (i = 0; i < 3; i++)
2713                                 do_setitimer(i, &itimer, NULL);
2714                 }
2715                 spin_lock_irq(&current->sighand->siglock);
2716                 if (!fatal_signal_pending(current)) {
2717                         flush_sigqueue(&current->pending);
2718                         flush_sigqueue(&current->signal->shared_pending);
2719                         flush_signal_handlers(current, 1);
2720                         sigemptyset(&current->blocked);
2721                         recalc_sigpending();
2722                 }
2723                 spin_unlock_irq(&current->sighand->siglock);
2724         }
2726         /* Wake up the parent if it is waiting so that it can recheck
2727          * wait permission to the new task SID. */
2728         read_lock(&tasklist_lock);
2729         __wake_up_parent(current, current->real_parent);
2730         read_unlock(&tasklist_lock);
2733 /* superblock security operations */
2735 static int selinux_sb_alloc_security(struct super_block *sb)
2737         return superblock_alloc_security(sb);
2740 static void selinux_sb_free_security(struct super_block *sb)
2742         superblock_free_security(sb);
2745 static inline int match_prefix(char *prefix, int plen, char *option, int olen)
2747         if (plen > olen)
2748                 return 0;
2750         return !memcmp(prefix, option, plen);
2753 static inline int selinux_option(char *option, int len)
2755         return (match_prefix(CONTEXT_STR, sizeof(CONTEXT_STR)-1, option, len) ||
2756                 match_prefix(FSCONTEXT_STR, sizeof(FSCONTEXT_STR)-1, option, len) ||
2757                 match_prefix(DEFCONTEXT_STR, sizeof(DEFCONTEXT_STR)-1, option, len) ||
2758                 match_prefix(ROOTCONTEXT_STR, sizeof(ROOTCONTEXT_STR)-1, option, len) ||
2759                 match_prefix(LABELSUPP_STR, sizeof(LABELSUPP_STR)-1, option, len));
2762 static inline void take_option(char **to, char *from, int *first, int len)
2764         if (!*first) {
2765                 **to = ',';
2766                 *to += 1;
2767         } else
2768                 *first = 0;
2769         memcpy(*to, from, len);
2770         *to += len;
2773 static inline void take_selinux_option(char **to, char *from, int *first,
2774                                        int len)
2776         int current_size = 0;
2778         if (!*first) {
2779                 **to = '|';
2780                 *to += 1;
2781         } else
2782                 *first = 0;
2784         while (current_size < len) {
2785                 if (*from != '"') {
2786                         **to = *from;
2787                         *to += 1;
2788                 }
2789                 from += 1;
2790                 current_size += 1;
2791         }
2794 static int selinux_sb_copy_data(char *orig, char *copy)
2796         int fnosec, fsec, rc = 0;
2797         char *in_save, *in_curr, *in_end;
2798         char *sec_curr, *nosec_save, *nosec;
2799         int open_quote = 0;
2801         in_curr = orig;
2802         sec_curr = copy;
2804         nosec = (char *)get_zeroed_page(GFP_KERNEL);
2805         if (!nosec) {
2806                 rc = -ENOMEM;
2807                 goto out;
2808         }
2810         nosec_save = nosec;
2811         fnosec = fsec = 1;
2812         in_save = in_end = orig;
2814         do {
2815                 if (*in_end == '"')
2816                         open_quote = !open_quote;
2817                 if ((*in_end == ',' && open_quote == 0) ||
2818                                 *in_end == '\0') {
2819                         int len = in_end - in_curr;
2821                         if (selinux_option(in_curr, len))
2822                                 take_selinux_option(&sec_curr, in_curr, &fsec, len);
2823                         else
2824                                 take_option(&nosec, in_curr, &fnosec, len);
2826                         in_curr = in_end + 1;
2827                 }
2828         } while (*in_end++);
2830         strcpy(in_save, nosec_save);
2831         free_page((unsigned long)nosec_save);
2832 out:
2833         return rc;
2836 static int selinux_sb_remount(struct super_block *sb, void *data)
2838         int rc, i, *flags;
2839         struct security_mnt_opts opts;
2840         char *secdata, **mount_options;
2841         struct superblock_security_struct *sbsec = sb->s_security;
2843         if (!(sbsec->flags & SE_SBINITIALIZED))
2844                 return 0;
2846         if (!data)
2847                 return 0;
2849         if (sb->s_type->fs_flags & FS_BINARY_MOUNTDATA)
2850                 return 0;
2852         security_init_mnt_opts(&opts);
2853         secdata = alloc_secdata();
2854         if (!secdata)
2855                 return -ENOMEM;
2856         rc = selinux_sb_copy_data(data, secdata);
2857         if (rc)
2858                 goto out_free_secdata;
2860         rc = selinux_parse_opts_str(secdata, &opts);
2861         if (rc)
2862                 goto out_free_secdata;
2864         mount_options = opts.mnt_opts;
2865         flags = opts.mnt_opts_flags;
2867         for (i = 0; i < opts.num_mnt_opts; i++) {
2868                 u32 sid;
2870                 if (flags[i] == SBLABEL_MNT)
2871                         continue;
2872                 rc = security_context_str_to_sid(&selinux_state,
2873                                                  mount_options[i], &sid,
2874                                                  GFP_KERNEL);
2875                 if (rc) {
2876                         pr_warn("SELinux: security_context_str_to_sid"
2877                                "(%s) failed for (dev %s, type %s) errno=%d\n",
2878                                mount_options[i], sb->s_id, sb->s_type->name, rc);
2879                         goto out_free_opts;
2880                 }
2881                 rc = -EINVAL;
2882                 switch (flags[i]) {
2883                 case FSCONTEXT_MNT:
2884                         if (bad_option(sbsec, FSCONTEXT_MNT, sbsec->sid, sid))
2885                                 goto out_bad_option;
2886                         break;
2887                 case CONTEXT_MNT:
2888                         if (bad_option(sbsec, CONTEXT_MNT, sbsec->mntpoint_sid, sid))
2889                                 goto out_bad_option;
2890                         break;
2891                 case ROOTCONTEXT_MNT: {
2892                         struct inode_security_struct *root_isec;
2893                         root_isec = backing_inode_security(sb->s_root);
2895                         if (bad_option(sbsec, ROOTCONTEXT_MNT, root_isec->sid, sid))
2896                                 goto out_bad_option;
2897                         break;
2898                 }
2899                 case DEFCONTEXT_MNT:
2900                         if (bad_option(sbsec, DEFCONTEXT_MNT, sbsec->def_sid, sid))
2901                                 goto out_bad_option;
2902                         break;
2903                 default:
2904                         goto out_free_opts;
2905                 }
2906         }
2908         rc = 0;
2909 out_free_opts:
2910         security_free_mnt_opts(&opts);
2911 out_free_secdata:
2912         free_secdata(secdata);
2913         return rc;
2914 out_bad_option:
2915         pr_warn("SELinux: unable to change security options "
2916                "during remount (dev %s, type=%s)\n", sb->s_id,
2917                sb->s_type->name);
2918         goto out_free_opts;
2921 static int selinux_sb_kern_mount(struct super_block *sb, int flags, void *data)
2923         const struct cred *cred = current_cred();
2924         struct common_audit_data ad;
2925         int rc;
2927         rc = superblock_doinit(sb, data);
2928         if (rc)
2929                 return rc;
2931         /* Allow all mounts performed by the kernel */
2932         if (flags & MS_KERNMOUNT)
2933                 return 0;
2935         ad.type = LSM_AUDIT_DATA_DENTRY;
2936         ad.u.dentry = sb->s_root;
2937         return superblock_has_perm(cred, sb, FILESYSTEM__MOUNT, &ad);
2940 static int selinux_sb_statfs(struct dentry *dentry)
2942         const struct cred *cred = current_cred();
2943         struct common_audit_data ad;
2945         ad.type = LSM_AUDIT_DATA_DENTRY;
2946         ad.u.dentry = dentry->d_sb->s_root;
2947         return superblock_has_perm(cred, dentry->d_sb, FILESYSTEM__GETATTR, &ad);
2950 static int selinux_mount(const char *dev_name,
2951                          const struct path *path,
2952                          const char *type,
2953                          unsigned long flags,
2954                          void *data)
2956         const struct cred *cred = current_cred();
2958         if (flags & MS_REMOUNT)
2959                 return superblock_has_perm(cred, path->dentry->d_sb,
2960                                            FILESYSTEM__REMOUNT, NULL);
2961         else
2962                 return path_has_perm(cred, path, FILE__MOUNTON);
2965 static int selinux_umount(struct vfsmount *mnt, int flags)
2967         const struct cred *cred = current_cred();
2969         return superblock_has_perm(cred, mnt->mnt_sb,
2970                                    FILESYSTEM__UNMOUNT, NULL);
2973 /* inode security operations */
2975 static int selinux_inode_alloc_security(struct inode *inode)
2977         return inode_alloc_security(inode);
2980 static void selinux_inode_free_security(struct inode *inode)
2982         inode_free_security(inode);
2985 static int selinux_dentry_init_security(struct dentry *dentry, int mode,
2986                                         const struct qstr *name, void **ctx,
2987                                         u32 *ctxlen)
2989         u32 newsid;
2990         int rc;
2992         rc = selinux_determine_inode_label(current_security(),
2993                                            d_inode(dentry->d_parent), name,
2994                                            inode_mode_to_security_class(mode),
2995                                            &newsid);
2996         if (rc)
2997                 return rc;
2999         return security_sid_to_context(&selinux_state, newsid, (char **)ctx,
3000                                        ctxlen);
3003 static int selinux_dentry_create_files_as(struct dentry *dentry, int mode,
3004                                           struct qstr *name,
3005                                           const struct cred *old,
3006                                           struct cred *new)
3008         u32 newsid;
3009         int rc;
3010         struct task_security_struct *tsec;
3012         rc = selinux_determine_inode_label(old->security,
3013                                            d_inode(dentry->d_parent), name,
3014                                            inode_mode_to_security_class(mode),
3015                                            &newsid);
3016         if (rc)
3017                 return rc;
3019         tsec = new->security;
3020         tsec->create_sid = newsid;
3021         return 0;
3024 static int selinux_inode_init_security(struct inode *inode, struct inode *dir,
3025                                        const struct qstr *qstr,
3026                                        const char **name,
3027                                        void **value, size_t *len)
3029         const struct task_security_struct *tsec = current_security();
3030         struct superblock_security_struct *sbsec;
3031         u32 newsid, clen;
3032         int rc;
3033         char *context;
3035         sbsec = dir->i_sb->s_security;
3037         newsid = tsec->create_sid;
3039         rc = selinux_determine_inode_label(current_security(),
3040                 dir, qstr,
3041                 inode_mode_to_security_class(inode->i_mode),
3042                 &newsid);
3043         if (rc)
3044                 return rc;
3046         /* Possibly defer initialization to selinux_complete_init. */
3047         if (sbsec->flags & SE_SBINITIALIZED) {
3048                 struct inode_security_struct *isec = inode->i_security;
3049                 isec->sclass = inode_mode_to_security_class(inode->i_mode);
3050                 isec->sid = newsid;
3051                 isec->initialized = LABEL_INITIALIZED;
3052         }
3054         if (!selinux_state.initialized || !(sbsec->flags & SBLABEL_MNT))
3055                 return -EOPNOTSUPP;
3057         if (name)
3058                 *name = XATTR_SELINUX_SUFFIX;
3060         if (value && len) {
3061                 rc = security_sid_to_context_force(&selinux_state, newsid,
3062                                                    &context, &clen);
3063                 if (rc)
3064                         return rc;
3065                 *value = context;
3066                 *len = clen;
3067         }
3069         return 0;
3072 static int selinux_inode_create(struct inode *dir, struct dentry *dentry, umode_t mode)
3074         return may_create(dir, dentry, SECCLASS_FILE);
3077 static int selinux_inode_link(struct dentry *old_dentry, struct inode *dir, struct dentry *new_dentry)
3079         return may_link(dir, old_dentry, MAY_LINK);
3082 static int selinux_inode_unlink(struct inode *dir, struct dentry *dentry)
3084         return may_link(dir, dentry, MAY_UNLINK);
3087 static int selinux_inode_symlink(struct inode *dir, struct dentry *dentry, const char *name)
3089         return may_create(dir, dentry, SECCLASS_LNK_FILE);
3092 static int selinux_inode_mkdir(struct inode *dir, struct dentry *dentry, umode_t mask)
3094         return may_create(dir, dentry, SECCLASS_DIR);
3097 static int selinux_inode_rmdir(struct inode *dir, struct dentry *dentry)
3099         return may_link(dir, dentry, MAY_RMDIR);
3102 static int selinux_inode_mknod(struct inode *dir, struct dentry *dentry, umode_t mode, dev_t dev)
3104         return may_create(dir, dentry, inode_mode_to_security_class(mode));
3107 static int selinux_inode_rename(struct inode *old_inode, struct dentry *old_dentry,
3108                                 struct inode *new_inode, struct dentry *new_dentry)
3110         return may_rename(old_inode, old_dentry, new_inode, new_dentry);
3113 static int selinux_inode_readlink(struct dentry *dentry)
3115         const struct cred *cred = current_cred();
3117         return dentry_has_perm(cred, dentry, FILE__READ);
3120 static int selinux_inode_follow_link(struct dentry *dentry, struct inode *inode,
3121                                      bool rcu)
3123         const struct cred *cred = current_cred();
3124         struct common_audit_data ad;
3125         struct inode_security_struct *isec;
3126         u32 sid;
3128         validate_creds(cred);
3130         ad.type = LSM_AUDIT_DATA_DENTRY;
3131         ad.u.dentry = dentry;
3132         sid = cred_sid(cred);
3133         isec = inode_security_rcu(inode, rcu);
3134         if (IS_ERR(isec))
3135                 return PTR_ERR(isec);
3137         return avc_has_perm_flags(&selinux_state,
3138                                   sid, isec->sid, isec->sclass, FILE__READ, &ad,
3139                                   rcu ? MAY_NOT_BLOCK : 0);
3142 static noinline int audit_inode_permission(struct inode *inode,
3143                                            u32 perms, u32 audited, u32 denied,
3144                                            int result,
3145                                            unsigned flags)
3147         struct common_audit_data ad;
3148         struct inode_security_struct *isec = inode->i_security;
3149         int rc;
3151         ad.type = LSM_AUDIT_DATA_INODE;
3152         ad.u.inode = inode;
3154         rc = slow_avc_audit(&selinux_state,
3155                             current_sid(), isec->sid, isec->sclass, perms,
3156                             audited, denied, result, &ad, flags);
3157         if (rc)
3158                 return rc;
3159         return 0;
3162 static int selinux_inode_permission(struct inode *inode, int mask)
3164         const struct cred *cred = current_cred();
3165         u32 perms;
3166         bool from_access;
3167         unsigned flags = mask & MAY_NOT_BLOCK;
3168         struct inode_security_struct *isec;
3169         u32 sid;
3170         struct av_decision avd;
3171         int rc, rc2;
3172         u32 audited, denied;
3174         from_access = mask & MAY_ACCESS;
3175         mask &= (MAY_READ|MAY_WRITE|MAY_EXEC|MAY_APPEND);
3177         /* No permission to check.  Existence test. */
3178         if (!mask)
3179                 return 0;
3181         validate_creds(cred);
3183         if (unlikely(IS_PRIVATE(inode)))
3184                 return 0;
3186         perms = file_mask_to_av(inode->i_mode, mask);
3188         sid = cred_sid(cred);
3189         isec = inode_security_rcu(inode, flags & MAY_NOT_BLOCK);
3190         if (IS_ERR(isec))
3191                 return PTR_ERR(isec);
3193         rc = avc_has_perm_noaudit(&selinux_state,
3194                                   sid, isec->sid, isec->sclass, perms, 0, &avd);
3195         audited = avc_audit_required(perms, &avd, rc,
3196                                      from_access ? FILE__AUDIT_ACCESS : 0,
3197                                      &denied);
3198         if (likely(!audited))
3199                 return rc;
3201         rc2 = audit_inode_permission(inode, perms, audited, denied, rc, flags);
3202         if (rc2)
3203                 return rc2;
3204         return rc;
3207 static int selinux_inode_setattr(struct dentry *dentry, struct iattr *iattr)
3209         const struct cred *cred = current_cred();
3210         struct inode *inode = d_backing_inode(dentry);
3211         unsigned int ia_valid = iattr->ia_valid;
3212         __u32 av = FILE__WRITE;
3214         /* ATTR_FORCE is just used for ATTR_KILL_S[UG]ID. */
3215         if (ia_valid & ATTR_FORCE) {
3216                 ia_valid &= ~(ATTR_KILL_SUID | ATTR_KILL_SGID | ATTR_MODE |
3217                               ATTR_FORCE);
3218                 if (!ia_valid)
3219                         return 0;
3220         }
3222         if (ia_valid & (ATTR_MODE | ATTR_UID | ATTR_GID |
3223                         ATTR_ATIME_SET | ATTR_MTIME_SET | ATTR_TIMES_SET))
3224                 return dentry_has_perm(cred, dentry, FILE__SETATTR);
3226         if (selinux_policycap_openperm() &&
3227             inode->i_sb->s_magic != SOCKFS_MAGIC &&
3228             (ia_valid & ATTR_SIZE) &&
3229             !(ia_valid & ATTR_FILE))
3230                 av |= FILE__OPEN;
3232         return dentry_has_perm(cred, dentry, av);
3235 static int selinux_inode_getattr(const struct path *path)
3237         return path_has_perm(current_cred(), path, FILE__GETATTR);
3240 static bool has_cap_mac_admin(bool audit)
3242         const struct cred *cred = current_cred();
3243         int cap_audit = audit ? SECURITY_CAP_AUDIT : SECURITY_CAP_NOAUDIT;
3245         if (cap_capable(cred, &init_user_ns, CAP_MAC_ADMIN, cap_audit))
3246                 return false;
3247         if (cred_has_capability(cred, CAP_MAC_ADMIN, cap_audit, true))
3248                 return false;
3249         return true;
3252 static int selinux_inode_setxattr(struct dentry *dentry, const char *name,
3253                                   const void *value, size_t size, int flags)
3255         struct inode *inode = d_backing_inode(dentry);
3256         struct inode_security_struct *isec;
3257         struct superblock_security_struct *sbsec;
3258         struct common_audit_data ad;
3259         u32 newsid, sid = current_sid();
3260         int rc = 0;
3262         if (strcmp(name, XATTR_NAME_SELINUX)) {
3263                 rc = cap_inode_setxattr(dentry, name, value, size, flags);
3264                 if (rc)
3265                         return rc;
3267                 /* Not an attribute we recognize, so just check the
3268                    ordinary setattr permission. */
3269                 return dentry_has_perm(current_cred(), dentry, FILE__SETATTR);
3270         }
3272         sbsec = inode->i_sb->s_security;
3273         if (!(sbsec->flags & SBLABEL_MNT))
3274                 return -EOPNOTSUPP;
3276         if (!inode_owner_or_capable(inode))
3277                 return -EPERM;
3279         ad.type = LSM_AUDIT_DATA_DENTRY;
3280         ad.u.dentry = dentry;
3282         isec = backing_inode_security(dentry);
3283         rc = avc_has_perm(&selinux_state,
3284                           sid, isec->sid, isec->sclass,
3285                           FILE__RELABELFROM, &ad);
3286         if (rc)
3287                 return rc;
3289         rc = security_context_to_sid(&selinux_state, value, size, &newsid,
3290                                      GFP_KERNEL);
3291         if (rc == -EINVAL) {
3292                 if (!has_cap_mac_admin(true)) {
3293                         struct audit_buffer *ab;
3294                         size_t audit_size;
3296                         /* We strip a nul only if it is at the end, otherwise the
3297                          * context contains a nul and we should audit that */
3298                         if (value) {
3299                                 const char *str = value;
3301                                 if (str[size - 1] == '\0')
3302                                         audit_size = size - 1;
3303                                 else
3304                                         audit_size = size;
3305                         } else {
3306                                 audit_size = 0;
3307                         }
3308                         ab = audit_log_start(audit_context(),
3309                                              GFP_ATOMIC, AUDIT_SELINUX_ERR);
3310                         audit_log_format(ab, "op=setxattr invalid_context=");
3311                         audit_log_n_untrustedstring(ab, value, audit_size);
3312                         audit_log_end(ab);
3314                         return rc;
3315                 }
3316                 rc = security_context_to_sid_force(&selinux_state, value,
3317                                                    size, &newsid);
3318         }
3319         if (rc)
3320                 return rc;
3322         rc = avc_has_perm(&selinux_state,
3323                           sid, newsid, isec->sclass,
3324                           FILE__RELABELTO, &ad);
3325         if (rc)
3326                 return rc;
3328         rc = security_validate_transition(&selinux_state, isec->sid, newsid,
3329                                           sid, isec->sclass);
3330         if (rc)
3331                 return rc;
3333         return avc_has_perm(&selinux_state,
3334                             newsid,
3335                             sbsec->sid,
3336                             SECCLASS_FILESYSTEM,
3337                             FILESYSTEM__ASSOCIATE,
3338                             &ad);
3341 static void selinux_inode_post_setxattr(struct dentry *dentry, const char *name,
3342                                         const void *value, size_t size,
3343                                         int flags)
3345         struct inode *inode = d_backing_inode(dentry);
3346         struct inode_security_struct *isec;
3347         u32 newsid;
3348         int rc;
3350         if (strcmp(name, XATTR_NAME_SELINUX)) {
3351                 /* Not an attribute we recognize, so nothing to do. */
3352                 return;
3353         }
3355         rc = security_context_to_sid_force(&selinux_state, value, size,
3356                                            &newsid);
3357         if (rc) {
3358                 pr_err("SELinux:  unable to map context to SID"
3359                        "for (%s, %lu), rc=%d\n",
3360                        inode->i_sb->s_id, inode->i_ino, -rc);
3361                 return;
3362         }
3364         isec = backing_inode_security(dentry);
3365         spin_lock(&isec->lock);
3366         isec->sclass = inode_mode_to_security_class(inode->i_mode);
3367         isec->sid = newsid;
3368         isec->initialized = LABEL_INITIALIZED;
3369         spin_unlock(&isec->lock);
3371         return;
3374 static int selinux_inode_getxattr(struct dentry *dentry, const char *name)
3376         const struct cred *cred = current_cred();
3378         return dentry_has_perm(cred, dentry, FILE__GETATTR);
3381 static int selinux_inode_listxattr(struct dentry *dentry)
3383         const struct cred *cred = current_cred();
3385         return dentry_has_perm(cred, dentry, FILE__GETATTR);
3388 static int selinux_inode_removexattr(struct dentry *dentry, const char *name)
3390         if (strcmp(name, XATTR_NAME_SELINUX)) {
3391                 int rc = cap_inode_removexattr(dentry, name);
3392                 if (rc)
3393                         return rc;
3395                 /* Not an attribute we recognize, so just check the
3396                    ordinary setattr permission. */
3397                 return dentry_has_perm(current_cred(), dentry, FILE__SETATTR);
3398         }
3400         /* No one is allowed to remove a SELinux security label.
3401            You can change the label, but all data must be labeled. */
3402         return -EACCES;
3405 /*
3406  * Copy the inode security context value to the user.
3407  *
3408  * Permission check is handled by selinux_inode_getxattr hook.
3409  */
3410 static int selinux_inode_getsecurity(struct inode *inode, const char *name, void **buffer, bool alloc)
3412         u32 size;
3413         int error;
3414         char *context = NULL;
3415         struct inode_security_struct *isec;
3417         if (strcmp(name, XATTR_SELINUX_SUFFIX))
3418                 return -EOPNOTSUPP;
3420         /*
3421          * If the caller has CAP_MAC_ADMIN, then get the raw context
3422          * value even if it is not defined by current policy; otherwise,
3423          * use the in-core value under current policy.
3424          * Use the non-auditing forms of the permission checks since
3425          * getxattr may be called by unprivileged processes commonly
3426          * and lack of permission just means that we fall back to the
3427          * in-core context value, not a denial.
3428          */
3429         isec = inode_security(inode);
3430         if (has_cap_mac_admin(false))
3431                 error = security_sid_to_context_force(&selinux_state,
3432                                                       isec->sid, &context,
3433                                                       &size);
3434         else
3435                 error = security_sid_to_context(&selinux_state, isec->sid,
3436                                                 &context, &size);
3437         if (error)
3438                 return error;
3439         error = size;
3440         if (alloc) {
3441                 *buffer = context;
3442                 goto out_nofree;
3443         }
3444         kfree(context);
3445 out_nofree:
3446         return error;
3449 static int selinux_inode_setsecurity(struct inode *inode, const char *name,
3450                                      const void *value, size_t size, int flags)
3452         struct inode_security_struct *isec = inode_security_novalidate(inode);
3453         u32 newsid;
3454         int rc;
3456         if (strcmp(name, XATTR_SELINUX_SUFFIX))
3457                 return -EOPNOTSUPP;
3459         if (!value || !size)
3460                 return -EACCES;
3462         rc = security_context_to_sid(&selinux_state, value, size, &newsid,
3463                                      GFP_KERNEL);
3464         if (rc)
3465                 return rc;
3467         spin_lock(&isec->lock);
3468         isec->sclass = inode_mode_to_security_class(inode->i_mode);
3469         isec->sid = newsid;
3470         isec->initialized = LABEL_INITIALIZED;
3471         spin_unlock(&isec->lock);
3472         return 0;
3475 static int selinux_inode_listsecurity(struct inode *inode, char *buffer, size_t buffer_size)
3477         const int len = sizeof(XATTR_NAME_SELINUX);
3478         if (buffer && len <= buffer_size)
3479                 memcpy(buffer, XATTR_NAME_SELINUX, len);
3480         return len;
3483 static void selinux_inode_getsecid(struct inode *inode, u32 *secid)
3485         struct inode_security_struct *isec = inode_security_novalidate(inode);
3486         *secid = isec->sid;
3489 static int selinux_inode_copy_up(struct dentry *src, struct cred **new)
3491         u32 sid;
3492         struct task_security_struct *tsec;
3493         struct cred *new_creds = *new;
3495         if (new_creds == NULL) {
3496                 new_creds = prepare_creds();
3497                 if (!new_creds)
3498                         return -ENOMEM;
3499         }
3501         tsec = new_creds->security;
3502         /* Get label from overlay inode and set it in create_sid */
3503         selinux_inode_getsecid(d_inode(src), &sid);
3504         tsec->create_sid = sid;
3505         *new = new_creds;
3506         return 0;
3509 static int selinux_inode_copy_up_xattr(const char *name)
3511         /* The copy_up hook above sets the initial context on an inode, but we
3512          * don't then want to overwrite it by blindly copying all the lower
3513          * xattrs up.  Instead, we have to filter out SELinux-related xattrs.
3514          */
3515         if (strcmp(name, XATTR_NAME_SELINUX) == 0)
3516                 return 1; /* Discard */
3517         /*
3518          * Any other attribute apart from SELINUX is not claimed, supported
3519          * by selinux.
3520          */
3521         return -EOPNOTSUPP;
3524 /* file security operations */
3526 static int selinux_revalidate_file_permission(struct file *file, int mask)
3528         const struct cred *cred = current_cred();
3529         struct inode *inode = file_inode(file);
3531         /* file_mask_to_av won't add FILE__WRITE if MAY_APPEND is set */
3532         if ((file->f_flags & O_APPEND) && (mask & MAY_WRITE))
3533                 mask |= MAY_APPEND;
3535         return file_has_perm(cred, file,
3536                              file_mask_to_av(inode->i_mode, mask));
3539 static int selinux_file_permission(struct file *file, int mask)
3541         struct inode *inode = file_inode(file);
3542         struct file_security_struct *fsec = file->f_security;
3543         struct inode_security_struct *isec;
3544         u32 sid = current_sid();
3546         if (!mask)
3547                 /* No permission to check.  Existence test. */
3548                 return 0;
3550         isec = inode_security(inode);
3551         if (sid == fsec->sid && fsec->isid == isec->sid &&
3552             fsec->pseqno == avc_policy_seqno(&selinux_state))
3553                 /* No change since file_open check. */
3554                 return 0;
3556         return selinux_revalidate_file_permission(file, mask);
3559 static int selinux_file_alloc_security(struct file *file)
3561         return file_alloc_security(file);
3564 static void selinux_file_free_security(struct file *file)
3566         file_free_security(file);
3569 /*
3570  * Check whether a task has the ioctl permission and cmd
3571  * operation to an inode.
3572  */
3573 static int ioctl_has_perm(const struct cred *cred, struct file *file,
3574                 u32 requested, u16 cmd)
3576         struct common_audit_data ad;
3577         struct file_security_struct *fsec = file->f_security;
3578         struct inode *inode = file_inode(file);
3579         struct inode_security_struct *isec;
3580         struct lsm_ioctlop_audit ioctl;
3581         u32 ssid = cred_sid(cred);
3582         int rc;
3583         u8 driver = cmd >> 8;
3584         u8 xperm = cmd & 0xff;
3586         ad.type = LSM_AUDIT_DATA_IOCTL_OP;
3587         ad.u.op = &ioctl;
3588         ad.u.op->cmd = cmd;
3589         ad.u.op->path = file->f_path;
3591         if (ssid != fsec->sid) {
3592                 rc = avc_has_perm(&selinux_state,
3593                                   ssid, fsec->sid,
3594                                 SECCLASS_FD,
3595                                 FD__USE,
3596                                 &ad);
3597                 if (rc)
3598                         goto out;
3599         }
3601         if (unlikely(IS_PRIVATE(inode)))
3602                 return 0;
3604         isec = inode_security(inode);
3605         rc = avc_has_extended_perms(&selinux_state,
3606                                     ssid, isec->sid, isec->sclass,
3607                                     requested, driver, xperm, &ad);
3608 out:
3609         return rc;
3612 static int selinux_file_ioctl(struct file *file, unsigned int cmd,
3613                               unsigned long arg)
3615         const struct cred *cred = current_cred();
3616         int error = 0;
3618         switch (cmd) {
3619         case FIONREAD:
3620         /* fall through */
3621         case FIBMAP:
3622         /* fall through */
3623         case FIGETBSZ:
3624         /* fall through */
3625         case FS_IOC_GETFLAGS:
3626         /* fall through */
3627         case FS_IOC_GETVERSION:
3628                 error = file_has_perm(cred, file, FILE__GETATTR);
3629                 break;
3631         case FS_IOC_SETFLAGS:
3632         /* fall through */
3633         case FS_IOC_SETVERSION:
3634                 error = file_has_perm(cred, file, FILE__SETATTR);
3635                 break;
3637         /* sys_ioctl() checks */
3638         case FIONBIO:
3639         /* fall through */
3640         case FIOASYNC:
3641                 error = file_has_perm(cred, file, 0);
3642                 break;
3644         case KDSKBENT:
3645         case KDSKBSENT:
3646                 error = cred_has_capability(cred, CAP_SYS_TTY_CONFIG,
3647                                             SECURITY_CAP_AUDIT, true);
3648                 break;
3650         /* default case assumes that the command will go
3651          * to the file's ioctl() function.
3652          */
3653         default:
3654                 error = ioctl_has_perm(cred, file, FILE__IOCTL, (u16) cmd);
3655         }
3656         return error;
3659 static int default_noexec;
3661 static int file_map_prot_check(struct file *file, unsigned long prot, int shared)
3663         const struct cred *cred = current_cred();
3664         u32 sid = cred_sid(cred);
3665         int rc = 0;
3667         if (default_noexec &&
3668             (prot & PROT_EXEC) && (!file || IS_PRIVATE(file_inode(file)) ||
3669                                    (!shared && (prot & PROT_WRITE)))) {
3670                 /*
3671                  * We are making executable an anonymous mapping or a
3672                  * private file mapping that will also be writable.
3673                  * This has an additional check.
3674                  */
3675                 rc = avc_has_perm(&selinux_state,
3676                                   sid, sid, SECCLASS_PROCESS,
3677                                   PROCESS__EXECMEM, NULL);
3678                 if (rc)
3679                         goto error;
3680         }
3682         if (file) {
3683                 /* read access is always possible with a mapping */
3684                 u32 av = FILE__READ;
3686                 /* write access only matters if the mapping is shared */
3687                 if (shared && (prot & PROT_WRITE))
3688                         av |= FILE__WRITE;
3690                 if (prot & PROT_EXEC)
3691                         av |= FILE__EXECUTE;
3693                 return file_has_perm(cred, file, av);
3694         }
3696 error:
3697         return rc;
3700 static int selinux_mmap_addr(unsigned long addr)
3702         int rc = 0;
3704         if (addr < CONFIG_LSM_MMAP_MIN_ADDR) {
3705                 u32 sid = current_sid();
3706                 rc = avc_has_perm(&selinux_state,
3707                                   sid, sid, SECCLASS_MEMPROTECT,
3708                                   MEMPROTECT__MMAP_ZERO, NULL);
3709         }
3711         return rc;
3714 static int selinux_mmap_file(struct file *file, unsigned long reqprot,
3715                              unsigned long prot, unsigned long flags)
3717         struct common_audit_data ad;
3718         int rc;
3720         if (file) {
3721                 ad.type = LSM_AUDIT_DATA_FILE;
3722                 ad.u.file = file;
3723                 rc = inode_has_perm(current_cred(), file_inode(file),
3724                                     FILE__MAP, &ad);
3725                 if (rc)
3726                         return rc;
3727         }
3729         if (selinux_state.checkreqprot)
3730                 prot = reqprot;
3732         return file_map_prot_check(file, prot,
3733                                    (flags & MAP_TYPE) == MAP_SHARED);
3736 static int selinux_file_mprotect(struct vm_area_struct *vma,
3737                                  unsigned long reqprot,
3738                                  unsigned long prot)
3740         const struct cred *cred = current_cred();
3741         u32 sid = cred_sid(cred);
3743         if (selinux_state.checkreqprot)
3744                 prot = reqprot;
3746         if (default_noexec &&
3747             (prot & PROT_EXEC) && !(vma->vm_flags & VM_EXEC)) {
3748                 int rc = 0;
3749                 if (vma->vm_start >= vma->vm_mm->start_brk &&
3750                     vma->vm_end <= vma->vm_mm->brk) {