audit: Syscall rules are not applied to existing processes on non-x86
Commit b05d8447e782 (audit: inline audit_syscall_entry to reduce
burden on archs) changed audit_syscall_entry to check for a dummy
context before calling __audit_syscall_entry. Unfortunately the dummy
context state is maintained in __audit_syscall_entry so once set it
never gets cleared, even if the audit rules change.
As a result, if there are no auditing rules when a process starts
then it will never be subject to any rules added later. x86 doesn't
see this because it has an assembly fast path that calls directly into
__audit_syscall_entry.
I noticed this issue when working on audit performance optimisations.
I wrote a set of simple test cases available at:
http://ozlabs.org/~anton/junkcode/audit_tests.tar.gz
02_new_rule.py fails without the patch and passes with it. The
test case clears all rules, starts a process, adds a rule then
verifies the process produces a syscall audit record.
Signed-off-by: Anton Blanchard <anton@samba.org>
Cc: <stable@kernel.org> # 3.3+
Signed-off-by: Eric Paris <eparis@redhat.com>
diff --git a/include/linux/audit.h b/include/linux/audit.h
index 5a6d718..37464c5 100644
--- a/include/linux/audit.h
+++ b/include/linux/audit.h
@@ -120,7 +120,7 @@
unsigned long a1, unsigned long a2,
unsigned long a3)
{
- if (unlikely(!audit_dummy_context()))
+ if (unlikely(current->audit_context))
__audit_syscall_entry(arch, major, a0, a1, a2, a3);
}
static inline void audit_syscall_exit(void *pt_regs)