linux/security/selinux/include
Ondrej Mosnacek fede148324 selinux: log invalid contexts in AVCs
In case a file has an invalid context set, in an AVC record generated
upon access to such file, the target context is always reported as
unlabeled. This patch adds new optional fields to the AVC record
(srawcon and trawcon) that report the actual context string if it
differs from the one reported in scontext/tcontext. This is useful for
diagnosing SELinux denials involving invalid contexts.

To trigger an AVC that illustrates this situation:

    # setenforce 0
    # touch /tmp/testfile
    # setfattr -n security.selinux -v system_u:object_r:banana_t:s0 /tmp/testfile
    # runcon system_u:system_r:sshd_t:s0 cat /tmp/testfile

AVC before:

type=AVC msg=audit(1547801083.248:11): avc:  denied  { open } for  pid=1149 comm="cat" path="/tmp/testfile" dev="tmpfs" ino=6608 scontext=system_u:system_r:sshd_t:s0 tcontext=system_u:object_r:unlabeled_t:s15:c0.c1023 tclass=file permissive=1

AVC after:

type=AVC msg=audit(1547801083.248:11): avc:  denied  { open } for  pid=1149 comm="cat" path="/tmp/testfile" dev="tmpfs" ino=6608 scontext=system_u:system_r:sshd_t:s0 tcontext=system_u:object_r:unlabeled_t:s15:c0.c1023 tclass=file permissive=1 trawcon=system_u:object_r:banana_t:s0

Note that it is also possible to encounter this situation with the
'scontext' field - e.g. when a new policy is loaded while a process is
running, whose context is not valid in the new policy.

Link: https://bugzilla.redhat.com/show_bug.cgi?id=1135683

Cc: Daniel Walsh <dwalsh@redhat.com>
Signed-off-by: Ondrej Mosnacek <omosnace@redhat.com>
Reviewed-by: Stephen Smalley <sds@tycho.nsa.gov>
Signed-off-by: Paul Moore <paul@paul-moore.com>
2019-01-25 17:31:14 -05:00
..
audit.h SELinux: keep the code clean formating and syntax 2008-07-14 15:01:36 +10:00
avc_ss.h selinux: wrap AVC state 2018-03-20 16:58:17 -04:00
avc.h selinux: stop passing MAY_NOT_BLOCK to the AVC upon follow_link 2019-01-10 20:34:37 -05:00
classmap.h net: initial AF_XDP skeleton 2018-05-03 15:55:23 -07:00
conditional.h selinux: wrap global selinux state 2018-03-01 18:48:02 -05:00
ibpkey.h selinux: Add a cache for quicker retreival of PKey SIDs 2017-05-23 12:28:12 -04:00
initial_sid_to_string.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
netif.h selinux: make the netif cache namespace aware 2014-09-10 17:09:57 -04:00
netlabel.h selinux: fix typo in selinux_netlbl_sctp_sk_clone declaration 2018-02-26 17:45:32 -05:00
netnode.h selinux: reduce the number of calls to synchronize_net() when flushing caches 2014-06-26 14:33:56 -04:00
netport.h selinux: reduce the number of calls to synchronize_net() when flushing caches 2014-06-26 14:33:56 -04:00
objsec.h selinux: wrap global selinux state 2018-03-01 18:48:02 -05:00
security.h selinux: log invalid contexts in AVCs 2019-01-25 17:31:14 -05:00
xfrm.h security: Remove rtnl_lock() in selinux_xfrm_notify_policyload() 2018-03-29 13:47:53 -04:00