From 2829a267fca297983b9302fa2cb833757328c857 Mon Sep 17 00:00:00 2001 From: Pavel Begunkov Date: Thu, 21 Jul 2022 15:25:46 +0100 Subject: [PATCH] net: fix uninitialised msghdr->sg_from_iter Because of how struct msghdr is usually initialised some fields and sg_from_iter in particular might be left out not initialised, so we can't safely use it in __zerocopy_sg_from_iter(). For now use the callback only when there is ->msg_ubuf set relying on the fact that they're used together and we properly zero ->msg_ubuf. Fixes: ebe73a284f4de8 ("net: Allow custom iter handler in msghdr") Signed-off-by: Pavel Begunkov Message-Id: Signed-off-by: Jakub Kicinski --- net/core/datagram.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/net/core/datagram.c b/net/core/datagram.c index 28cdb79..ecbc0f4 100644 --- a/net/core/datagram.c +++ b/net/core/datagram.c @@ -619,7 +619,7 @@ int __zerocopy_sg_from_iter(struct msghdr *msg, struct sock *sk, { int frag; - if (msg && msg->sg_from_iter) + if (msg && msg->msg_ubuf && msg->sg_from_iter) return msg->sg_from_iter(sk, skb, from, length); frag = skb_shinfo(skb)->nr_frags; -- 2.7.4