From: Pengcheng Yang yangpc@wangsu.com
[ 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: 604326b41a6f ("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.c... Signed-off-by: Sasha Levin sashal@kernel.org --- net/ipv4/tcp_bpf.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-)
diff --git a/net/ipv4/tcp_bpf.c b/net/ipv4/tcp_bpf.c index 027f7f9256e1..6a1685461f89 100644 --- a/net/ipv4/tcp_bpf.c +++ b/net/ipv4/tcp_bpf.c @@ -125,8 +125,11 @@ 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);