USB: pid_ns: ensure pid is not freed during kill_pid_info_as_uid

Alan Stern points out that after spin_unlock(&ps->lock) there is no guarantee that ps->pid won't be freed. Since kill_pid_info_as_uid() is called after the spin_unlock(), the pid passed to it must be pinned. Reported-by: Alan Stern <[email protected]> Signed-off-by: Serge Hallyn <[email protected]> Cc: stable <[email protected]> Signed-off-by: Greg Kroah-Hartman <[email protected]>
jadonk · Sep 26, 2011 · aec01c5 · aec01c5
1 parent 5c12e78
commit aec01c5
Showing 1 changed file with 4 additions and 2 deletions.
diff --git a/drivers/usb/core/devio.c b/drivers/usb/core/devio.c
@@ -407,7 +407,7 @@ static void async_completed(struct urb *urb)
 		sinfo.si_errno = as->status;
 		sinfo.si_code = SI_ASYNCIO;
 		sinfo.si_addr = as->userurb;
-		pid = as->pid;
+		pid = get_pid(as->pid);
 		uid = as->uid;
 		euid = as->euid;
 		secid = as->secid;
@@ -422,9 +422,11 @@ static void async_completed(struct urb *urb)
 		cancel_bulk_urbs(ps, as->bulk_addr);
 	spin_unlock(&ps->lock);
 
-	if (signr)
+	if (signr) {
 		kill_pid_info_as_uid(sinfo.si_signo, &sinfo, pid, uid,
 				      euid, secid);
+		put_pid(pid);
+	}
 
 	wake_up(&ps->wait);
 }