Commit 9072931f authored by Pengcheng Yang's avatar Pengcheng Yang Committed by Daniel Borkmann
Browse files

bpf, sockmap: Fix data loss caused by using apply_bytes on ingress redirect 



Use apply_bytes on ingress redirect, when apply_bytes is less than
the length of msg data, some data may be skipped and lost in
bpf_tcp_ingress().

If there is still data in the scatterlist that has not been consumed,
we cannot move the msg iter.

Fixes: 604326b4 ("bpf, sockmap: convert to generic sk_msg interface")
Signed-off-by: default avatarPengcheng Yang <yangpc@wangsu.com>
Signed-off-by: default avatarDaniel Borkmann <daniel@iogearbox.net>
Acked-by: default avatarJakub Sitnicki <jakub@cloudflare.com>
Link: https://lore.kernel.org/bpf/1669718441-2654-4-git-send-email-yangpc@wangsu.com
parent a351d608

net/ipv4/tcp_bpf.c

+4 −1
Original line number Diff line number Diff line
@@ -45,9 +45,12 @@ static int bpf_tcp_ingress(struct sock *sk, struct sk_psock *psock, 
		tmp->sg.end = i;

		if (apply) {

			apply_bytes -= size;

			if (!apply_bytes)

			if (!apply_bytes) {

				if (sge->length)

					sk_msg_iter_var_prev(i);

				break;

			}

		}

	} while (i != msg->sg.end);



	if (!ret) {