tree 108048107fccd45acf12bf35205d095b7a57d68f
parent 8c8e04fbcb017d4e030b12f116385dcc5d11531f
author Todd Kjos <tkjos@google.com> 1634057773 -0700
committer Karsten Tausche <karsten@fairphone.com> 1648458789 +0200

BACKPORT: binder: use cred instead of task for selinux checks

commit 52f88693378a58094c538662ba652aff0253c4fe upstream.

Since binder was integrated with selinux, it has passed
'struct task_struct' associated with the binder_proc
to represent the source and target of transactions.
The conversion of task to SID was then done in the hook
implementations. It turns out that there are race conditions
which can result in an incorrect security context being used.

Fix by using the 'struct cred' saved during binder_open and pass
it to the selinux subsystem.

Cc: stable@vger.kernel.org # 5.14 (need backport for earlier stables)
Fixes: 79af73079d75 ("Add security hooks to binder and implement the hooks for SELinux.")
Suggested-by: Jann Horn <jannh@google.com>
Signed-off-by: Todd Kjos <tkjos@google.com>
Acked-by: Casey Schaufler <casey@schaufler-ca.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
Change-Id: Id7157515d2b08f11683aeb8ad9b8f1da075d34e7
[ tkjos@ fixed minor conflicts ]
Bug: 200688826
Signed-off-by: Todd Kjos <tkjos@google.com>
Issue: FP3SEC-266
(cherry picked from commit a69d9cd3d44dd9e9964b19740567620233ed6f17)