AppArmor: Fix reference to rcu protected pointer outside of rcu_read_lock
commit 04fdc099f9c80c7775dbac388fc97e156d4d47e7 upstream.
The pointer returned from tracehook_tracer_task() is only valid inside
the rcu_read_lock. However the tracer pointer obtained is being passed
to aa_may_ptrace outside of the rcu_read_lock critical section.
Mover the aa_may_ptrace test into the rcu_read_lock critical section, to
fix this.
Kernels affected: 2.6.36 - 3.0
Reported-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: John Johansen <john.johansen@canonical.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
diff --git a/security/apparmor/domain.c b/security/apparmor/domain.c
index c825c6e..78adc43 100644
--- a/security/apparmor/domain.c
+++ b/security/apparmor/domain.c
@@ -73,7 +73,6 @@
cred = get_task_cred(tracer);
tracerp = aa_cred_profile(cred);
}
- rcu_read_unlock();
/* not ptraced */
if (!tracer || unconfined(tracerp))
@@ -82,6 +81,7 @@
error = aa_may_ptrace(tracer, tracerp, to_profile, PTRACE_MODE_ATTACH);
out:
+ rcu_read_unlock();
if (cred)
put_cred(cred);