Re: [PATCH -v2] Audit: push audit success and retcode into arch ptrace.h

[Oleg Nesterov <oleg@redhat.com>]

On 06/08, Oleg Nesterov wrote:
>
> OK. Thanks a lot Eric for your explanations.

Yes. but may I ask another one?

Shouldn't copy_process()->audit_alloc(tsk) path do
clear_tsk_thread_flag(tsk, TIF_SYSCALL_AUDIT) if it doesn't
set tsk->audit_context?

I can be easily wrong, but afaics otherwise the child can run
with TIF_SYSCALL_AUDIT bit copied from parent's thread_info by
dup_task_struct()->setup_thread_stack() and without ->audit_context,
right? For what?

Any other reason why audit_syscall_entry() checks context != NULL?

IOW. Any reason the patch below is wrong?

I am just curious, thanks.

Oleg.

--- x/kernel/auditsc.c
+++ x/kernel/auditsc.c
@@ -885,6 +885,8 @@ int audit_alloc(struct task_struct *tsk)
 	if (likely(!audit_ever_enabled))
 		return 0; /* Return if not auditing. */
 
+	clear_tsk_thread_flag(tsk, TIF_SYSCALL_AUDIT);
+
 	state = audit_filter_task(tsk, &key);
 	if (likely(state == AUDIT_DISABLED))
 		return 0;
@@ -1591,9 +1593,7 @@ void audit_syscall_entry(int arch, int m
 	struct audit_context *context = tsk->audit_context;
 	enum audit_state     state;
 
-	if (unlikely(!context))
-		return;
-
+	BUG_ON(!context);
 	/*
 	 * This happens only on certain architectures that make system
 	 * calls in kernel_thread via the entry.S interface, instead of