[13/65] audit: Syscall rules are not applied to existing processes on non-x86

Steven Rostedt
2013-06-03T22:23:12Z

[-- Attachment #1: 0013-audit-Syscall-rules-are-not-applied-to-existing-proc.patch --]
[-- Type: text/plain, Size: 1904 bytes --]

3.6.11.5 stable review patch.
If anyone has any objections, please let me know.

------------------

From: Anton Blanchard <anton@samba.org>

[ Upstream commit cdee3904b4ce7c03d1013ed6dd704b43ae7fc2e9 ]

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>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
---
include/linux/audit.h | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/include/linux/audit.h b/include/linux/audit.h
index 36abf2a..a36d567 100644
--- a/include/linux/audit.h
+++ b/include/linux/audit.h
@@ -481,7 +481,7 @@ static inline void audit_syscall_entry(int arch, int major, unsigned long a0,
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)
--
1.7.10.4