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authorLinus Torvalds2013-04-14 12:06:31 -0500
committerGreg Kroah-Hartman2013-04-26 14:18:20 -0500
commit97129f70b9a32ddf8929daacd2abee36a7f0ddad (patch)
tree0f6bcfc24b2b7e90eff69d4f4550e7c43e2073b3 /kernel
parent8299a17a0544a45529a954cf27f9bf40e8890ac6 (diff)
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Add file_ns_capable() helper function for open-time capability checking
commit 935d8aabd4331f47a89c3e1daa5779d23cf244ee upstream. Nothing is using it yet, but this will allow us to delay the open-time checks to use time, without breaking the normal UNIX permission semantics where permissions are determined by the opener (and the file descriptor can then be passed to a different process, or the process can drop capabilities). Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Cc: Shea Levy <shea@shealevy.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'kernel')
-rw-r--r--kernel/capability.c24
1 files changed, 24 insertions, 0 deletions
diff --git a/kernel/capability.c b/kernel/capability.c
index 493d97259484..f6c2ce5701e1 100644
--- a/kernel/capability.c
+++ b/kernel/capability.c
@@ -393,6 +393,30 @@ bool ns_capable(struct user_namespace *ns, int cap)
393EXPORT_SYMBOL(ns_capable); 393EXPORT_SYMBOL(ns_capable);
394 394
395/** 395/**
396 * file_ns_capable - Determine if the file's opener had a capability in effect
397 * @file: The file we want to check
398 * @ns: The usernamespace we want the capability in
399 * @cap: The capability to be tested for
400 *
401 * Return true if task that opened the file had a capability in effect
402 * when the file was opened.
403 *
404 * This does not set PF_SUPERPRIV because the caller may not
405 * actually be privileged.
406 */
407bool file_ns_capable(const struct file *file, struct user_namespace *ns, int cap)
408{
409 if (WARN_ON_ONCE(!cap_valid(cap)))
410 return false;
411
412 if (security_capable(file->f_cred, ns, cap) == 0)
413 return true;
414
415 return false;
416}
417EXPORT_SYMBOL(file_ns_capable);
418
419/**
396 * capable - Determine if the current task has a superior capability in effect 420 * capable - Determine if the current task has a superior capability in effect
397 * @cap: The capability to be tested for 421 * @cap: The capability to be tested for
398 * 422 *