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Diffstat (limited to 'kernel/signal.c')
-rw-r--r--kernel/signal.c24
1 files changed, 19 insertions, 5 deletions
diff --git a/kernel/signal.c b/kernel/signal.c
index 251cc13720bd..24be82c0aae3 100644
--- a/kernel/signal.c
+++ b/kernel/signal.c
@@ -533,6 +533,7 @@ static int rm_from_queue(unsigned long mask, struct sigpending *s)
static int check_kill_permission(int sig, struct siginfo *info,
struct task_struct *t)
{
+ struct pid *sid;
int error;
if (!valid_signal(sig))
@@ -545,11 +546,24 @@ static int check_kill_permission(int sig, struct siginfo *info,
if (error)
return error;
- if (((sig != SIGCONT) || (task_session_nr(current) != task_session_nr(t)))
- && (current->euid ^ t->suid) && (current->euid ^ t->uid)
- && (current->uid ^ t->suid) && (current->uid ^ t->uid)
- && !capable(CAP_KILL))
- return -EPERM;
+ if ((current->euid ^ t->suid) && (current->euid ^ t->uid) &&
+ (current->uid ^ t->suid) && (current->uid ^ t->uid) &&
+ !capable(CAP_KILL)) {
+ switch (sig) {
+ case SIGCONT:
+ read_lock(&tasklist_lock);
+ sid = task_session(t);
+ read_unlock(&tasklist_lock);
+ /*
+ * We don't return the error if sid == NULL. The
+ * task was unhashed, the caller must notice this.
+ */
+ if (!sid || sid == task_session(current))
+ break;
+ default:
+ return -EPERM;
+ }
+ }
return security_task_kill(t, info, sig, 0);
}