Async signals should not be reported as sent by current in
audit log. As it is, we call audit_signal_info() too early in
check_kill_permission(). Note that check_kill_permission() has that
test already - it needs to know if it should apply current-based
permission checks. So the solution is to move the call of audit_signal_info()
between those.
Bogosity in question is easily reproduced - add a rule watching for
e.g. kill(2) from specific process (so that audit_signal_info() would not
short-circuit to nothing), say load_policy, watch the bogus OBJ_PID entry
in audit logs claiming that write(2) on selinuxfs file issued by load_policy(8)
had somehow managed to send a signal to syslogd...
Signed-off-by: Al Viro <[email protected]>
Acked-by: Steve Grubb <[email protected]>
Acked-by: Eric Paris <[email protected]>
---
diff --git a/kernel/signal.c b/kernel/signal.c
index 9fb91a3..7929523 100644
--- a/kernel/signal.c
+++ b/kernel/signal.c
@@ -531,18 +531,18 @@ static int check_kill_permission(int sig, struct siginfo *info,
if (!valid_signal(sig))
return error;
- error = audit_signal_info(sig, t); /* Let audit system see the signal */
- if (error)
- return error;
-
- error = -EPERM;
- if ((info == SEND_SIG_NOINFO || (!is_si_special(info) && SI_FROMUSER(info)))
- && ((sig != SIGCONT) ||
- (process_session(current) != process_session(t)))
- && (current->euid ^ t->suid) && (current->euid ^ t->uid)
- && (current->uid ^ t->suid) && (current->uid ^ t->uid)
- && !capable(CAP_KILL))
+ if (info == SEND_SIG_NOINFO || (!is_si_special(info) && SI_FROMUSER(info))) {
+ error = audit_signal_info(sig, t); /* Let audit system see the signal */
+ if (error)
+ return error;
+ error = -EPERM;
+ if (((sig != SIGCONT) ||
+ (process_session(current) != process_session(t)))
+ && (current->euid ^ t->suid) && (current->euid ^ t->uid)
+ && (current->uid ^ t->suid) && (current->uid ^ t->uid)
+ && !capable(CAP_KILL))
return error;
+ }
return security_task_kill(t, info, sig, 0);
}