Re: [PATCH net v2 3/3] net: tcp: block standard payload injection into devmem skbs
Bobby Eshleman <[email protected]>
| Newsgroups | gmane.linux.network,gmane.linux.kernel |
|---|---|
| Message-ID | <[email protected]> |
On Mon, Aug 03, 2026 at 05:14:41PM +0000, Mina Almasry wrote:
> Protect tcp_sendmsg_locked() from mistakenly appending non-zerocopy
> page fragments to unreadable devmem skbs. Create a new segment instead.
>
> Fixes: bd61848900bff ("net: devmem: Implement TX path")
> Cc: Pavel Begunkov <[email protected]>
> Cc: Stanislav Fomichev <[email protected]>
> Cc: Bobby Eshleman <[email protected]>
> Signed-off-by: Mina Almasry <[email protected]>
> Reviewed-by: Pavel Begunkov <[email protected]>
> ---
> net/ipv4/tcp.c | 5 +++++
> 1 file changed, 5 insertions(+)
>
> diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c
> index 455441f1b6949..186a36c698798 100644
> --- a/net/ipv4/tcp.c
> +++ b/net/ipv4/tcp.c
> @@ -1278,6 +1278,11 @@ int tcp_sendmsg_locked(struct sock *sk, struct msghdr *msg, size_t size)
> if (copy > msg_data_left(msg))
> copy = msg_data_left(msg);
>
> + if (zc != MSG_ZEROCOPY && unlikely(!skb_frags_readable(skb))) {
> + tcp_mark_push(tp, skb);
> + goto new_segment;
> + }
> +
> if (zc == 0) {
> bool merge = true;
> int i = skb_shinfo(skb)->nr_frags;
> --
> 2.55.0.571.g244d577d93-goog
>
Reviewed-by: Bobby Eshleman <[email protected]>