From patchwork Tue Jan 8 23:46:17 2013 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Subject: [1/4] audit: Syscall rules are not applied to existing processes on non-x86 From: Anton Blanchard X-Patchwork-Id: 210572 Message-Id: <20130109104617.74e995a5@kryten> To: eparis@redhat.com, viro@zeniv.linux.org.uk, benh@kernel.crashing.org, paulus@samba.org Cc: linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org Date: Wed, 9 Jan 2013 10:46:17 +1100 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 Cc: # 3.3+ --- Index: b/include/linux/audit.h =================================================================== --- a/include/linux/audit.h +++ b/include/linux/audit.h @@ -119,7 +119,7 @@ static inline void audit_syscall_entry(i 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)