From c231740dd95e854de5034cff8f49737d942bc098 Mon Sep 17 00:00:00 2001 From: Markus Elfring Date: Wed, 25 Sep 2019 16:48:17 -0700 Subject: [PATCH] ipc/mqueue: improve exception handling in do_mq_notify() MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Null pointers were assigned to local variables in a few cases as exception handling. The jump target “out” was used where no meaningful data processing actions should eventually be performed by branches of an if statement then. Use an additional jump target for calling dev_kfree_skb() directly. Return also directly after error conditions were detected when no extra clean-up is needed by this function implementation. Link: http://lkml.kernel.org/r/592ef10e-0b69-72d0-9789-fc48f638fdfd@web.de Signed-off-by: Markus Elfring Cc: Davidlohr Bueso Cc: Manfred Spraul Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- ipc/mqueue.c | 20 ++++++++------------ 1 file changed, 8 insertions(+), 12 deletions(-) diff --git a/ipc/mqueue.c b/ipc/mqueue.c index b02eb842b42e..3d920ff15c80 100644 --- a/ipc/mqueue.c +++ b/ipc/mqueue.c @@ -1240,15 +1240,14 @@ static int do_mq_notify(mqd_t mqdes, const struct sigevent *notification) /* create the notify skb */ nc = alloc_skb(NOTIFY_COOKIE_LEN, GFP_KERNEL); - if (!nc) { - ret = -ENOMEM; - goto out; - } + if (!nc) + return -ENOMEM; + if (copy_from_user(nc->data, notification->sigev_value.sival_ptr, NOTIFY_COOKIE_LEN)) { ret = -EFAULT; - goto out; + goto free_skb; } /* TODO: add a header? */ @@ -1264,8 +1263,7 @@ retry: fdput(f); if (IS_ERR(sock)) { ret = PTR_ERR(sock); - sock = NULL; - goto out; + goto free_skb; } timeo = MAX_SCHEDULE_TIMEOUT; @@ -1274,11 +1272,8 @@ retry: sock = NULL; goto retry; } - if (ret) { - sock = NULL; - nc = NULL; - goto out; - } + if (ret) + return ret; } } @@ -1334,6 +1329,7 @@ out: if (sock) netlink_detachskb(sock, nc); else +free_skb: dev_kfree_skb(nc); return ret;