Commit 31631c2a authored Nov 29, 2022 by Pengcheng Yang Committed by Greg Kroah-Hartman Jan 18, 2023

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



[ Upstream commit 9072931f020bfd907d6d89ee21ff1481cd78b407 ]

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: Pengcheng Yang <yangpc@wangsu.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Jakub Sitnicki <jakub@cloudflare.com>
Link: https://lore.kernel.org/bpf/1669718441-2654-4-git-send-email-yangpc@wangsu.com


Signed-off-by: Sasha Levin <sashal@kernel.org>

parent 7508b9f4

net/ipv4/tcp_bpf.c

+4 −1

Original line number	Diff line number	Diff line
		@@ -203,9 +203,12 @@ 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) {