diff options
authorTrent Jaeger2005-12-14 01:12:27 -0600
committerDavid S. Miller2006-01-03 15:10:24 -0600
commitdf71837d5024e2524cd51c93621e558aa7dd9f3f (patch)
tree58938f1d46f3c6713b63e5a785e82fdbb10121a1 /security/Kconfig
parent88026842b0a760145aa71d69e74fbc9ec118ca44 (diff)
[LSM-IPSec]: Security association restriction.
This patch series implements per packet access control via the extension of the Linux Security Modules (LSM) interface by hooks in the XFRM and pfkey subsystems that leverage IPSec security associations to label packets. Extensions to the SELinux LSM are included that leverage the patch for this purpose. This patch implements the changes necessary to the XFRM subsystem, pfkey interface, ipv4/ipv6, and xfrm_user interface to restrict a socket to use only authorized security associations (or no security association) to send/receive network packets. Patch purpose: The patch is designed to enable access control per packets based on the strongly authenticated IPSec security association. Such access controls augment the existing ones based on network interface and IP address. The former are very coarse-grained, and the latter can be spoofed. By using IPSec, the system can control access to remote hosts based on cryptographic keys generated using the IPSec mechanism. This enables access control on a per-machine basis or per-application if the remote machine is running the same mechanism and trusted to enforce the access control policy. Patch design approach: The overall approach is that policy (xfrm_policy) entries set by user-level programs (e.g., setkey for ipsec-tools) are extended with a security context that is used at policy selection time in the XFRM subsystem to restrict the sockets that can send/receive packets via security associations (xfrm_states) that are built from those policies. A presentation available at www.selinux-symposium.org/2005/presentations/session2/2-3-jaeger.pdf from the SELinux symposium describes the overall approach. Patch implementation details: On output, the policy retrieved (via xfrm_policy_lookup or xfrm_sk_policy_lookup) must be authorized for the security context of the socket and the same security context is required for resultant security association (retrieved or negotiated via racoon in ipsec-tools). This is enforced in xfrm_state_find. On input, the policy retrieved must also be authorized for the socket (at __xfrm_policy_check), and the security context of the policy must also match the security association being used. The patch has virtually no impact on packets that do not use IPSec. The existing Netfilter (outgoing) and LSM rcv_skb hooks are used as before. Also, if IPSec is used without security contexts, the impact is minimal. The LSM must allow such policies to be selected for the combination of socket and remote machine, but subsequent IPSec processing proceeds as in the original case. Testing: The pfkey interface is tested using the ipsec-tools. ipsec-tools have been modified (a separate ipsec-tools patch is available for version 0.5) that supports assignment of xfrm_policy entries and security associations with security contexts via setkey and the negotiation using the security contexts via racoon. The xfrm_user interface is tested via ad hoc programs that set security contexts. These programs are also available from me, and contain programs for setting, getting, and deleting policy for testing this interface. Testing of sa functions was done by tracing kernel behavior. Signed-off-by: Trent Jaeger <tjaeger@cse.psu.edu> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'security/Kconfig')
1 files changed, 13 insertions, 0 deletions
diff --git a/security/Kconfig b/security/Kconfig
index 64d3f1e9ca8..34f593410d5 100644
--- a/security/Kconfig
+++ b/security/Kconfig
@@ -54,6 +54,19 @@ config SECURITY_NETWORK
54 implement socket and networking access controls. 54 implement socket and networking access controls.
55 If you are unsure how to answer this question, answer N. 55 If you are unsure how to answer this question, answer N.
56 56
58 bool "XFRM (IPSec) Networking Security Hooks"
59 depends on XFRM && SECURITY_NETWORK
60 help
61 This enables the XFRM (IPSec) networking security hooks.
62 If enabled, a security module can use these hooks to
63 implement per-packet access controls based on labels
64 derived from IPSec policy. Non-IPSec communications are
65 designated as unlabelled, and only sockets authorized
66 to communicate unlabelled data can send without using
67 IPSec.
68 If you are unsure how to answer this question, answer N.
58 tristate "Default Linux Capabilities" 71 tristate "Default Linux Capabilities"
59 depends on SECURITY 72 depends on SECURITY