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authorDavid Howells <dhowells@redhat.com>2009-04-29 13:45:05 +0100
committerJames Morris <jmorris@namei.org>2009-04-30 09:07:13 +1000
commit3bcac0263f0b45e67a64034ebcb69eb9abb742f4 (patch)
tree33f4db08edaa12e1c20df348e2fa28c7c2198ebe
parent88c48db9788862d0290831d081bc3c64e13b592f (diff)
downloadlinux-3bcac0263f0b45e67a64034ebcb69eb9abb742f4.tar.gz
SELinux: Don't flush inherited SIGKILL during execve()
Don't flush inherited SIGKILL during execve() in SELinux's post cred commit hook. This isn't really a security problem: if the SIGKILL came before the credentials were changed, then we were right to receive it at the time, and should honour it; if it came after the creds were changed, then we definitely should honour it; and in any case, all that will happen is that the process will be scrapped before it ever returns to userspace. Signed-off-by: David Howells <dhowells@redhat.com> Signed-off-by: Oleg Nesterov <oleg@redhat.com> Signed-off-by: James Morris <jmorris@namei.org>
-rw-r--r--include/linux/sched.h1
-rw-r--r--kernel/signal.c11
-rw-r--r--security/selinux/hooks.c9
3 files changed, 14 insertions, 7 deletions
diff --git a/include/linux/sched.h b/include/linux/sched.h
index 1d19c025f9d..d3b787c7aef 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -1875,6 +1875,7 @@ extern void sched_dead(struct task_struct *p);
extern void proc_caches_init(void);
extern void flush_signals(struct task_struct *);
+extern void __flush_signals(struct task_struct *);
extern void ignore_signals(struct task_struct *);
extern void flush_signal_handlers(struct task_struct *, int force_default);
extern int dequeue_signal(struct task_struct *tsk, sigset_t *mask, siginfo_t *info);
diff --git a/kernel/signal.c b/kernel/signal.c
index 1c8814481a1..f93efec14ff 100644
--- a/kernel/signal.c
+++ b/kernel/signal.c
@@ -238,14 +238,19 @@ void flush_sigqueue(struct sigpending *queue)
/*
* Flush all pending signals for a task.
*/
+void __flush_signals(struct task_struct *t)
+{
+ clear_tsk_thread_flag(t, TIF_SIGPENDING);
+ flush_sigqueue(&t->pending);
+ flush_sigqueue(&t->signal->shared_pending);
+}
+
void flush_signals(struct task_struct *t)
{
unsigned long flags;
spin_lock_irqsave(&t->sighand->siglock, flags);
- clear_tsk_thread_flag(t, TIF_SIGPENDING);
- flush_sigqueue(&t->pending);
- flush_sigqueue(&t->signal->shared_pending);
+ __flush_signals(t);
spin_unlock_irqrestore(&t->sighand->siglock, flags);
}
diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c
index dd19ba81201..5a345115036 100644
--- a/security/selinux/hooks.c
+++ b/security/selinux/hooks.c
@@ -2394,11 +2394,12 @@ static void selinux_bprm_committed_creds(struct linux_binprm *bprm)
memset(&itimer, 0, sizeof itimer);
for (i = 0; i < 3; i++)
do_setitimer(i, &itimer, NULL);
- flush_signals(current);
spin_lock_irq(&current->sighand->siglock);
- flush_signal_handlers(current, 1);
- sigemptyset(&current->blocked);
- recalc_sigpending();
+ if (!(current->signal->flags & SIGNAL_GROUP_EXIT)) {
+ __flush_signals(current);
+ flush_signal_handlers(current, 1);
+ sigemptyset(&current->blocked);
+ }
spin_unlock_irq(&current->sighand->siglock);
}