From 291041e935e6d0513f2b7e4a300aa9f02ec1d925 Mon Sep 17 00:00:00 2001 From: Al Viro Date: Sun, 7 Oct 2007 00:24:36 -0700 Subject: [PATCH] fix bogus reporting of signals by audit 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 Acked-by: Steve Grubb Acked-by: Eric Paris Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- kernel/signal.c | 22 +++++++++++----------- 1 file changed, 11 insertions(+), 11 deletions(-) diff --git a/kernel/signal.c b/kernel/signal.c index 9fb91a32edda..792952381092 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); }