| Message ID | ce8b68b41351488f79fd998b032b3c56e9b1cc6c.1658401817.git.asml.silence@gmail.com (mailing list archive) |
|---|---|
| State | Accepted |
| Commit | 2829a267fca297983b9302fa2cb833757328c857 |
| Delegated to: | Netdev Maintainers |
| Headers | show |
| Series | [net-next] net: fix uninitialised msghdr->sg_from_iter | expand |
Hello: This patch was applied to netdev/net-next.git (master) by Jakub Kicinski <kuba@kernel.org>: On Thu, 21 Jul 2022 15:25:46 +0100 you wrote: > 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. > > [...] Here is the summary with links: - [net-next] net: fix uninitialised msghdr->sg_from_iter https://git.kernel.org/netdev/net-next/c/2829a267fca2 You are awesome, thank you!
diff --git a/net/core/datagram.c b/net/core/datagram.c index 28cdb79df74d..ecbc0f471089 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;
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 <asml.silence@gmail.com> --- It's not the best approach long term but let's fix first and later I'm going to clean up msghdr initialisation. net/core/datagram.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)