This is a note to let you know that I've just added the patch titled bpf, sockmap: Fix data loss caused by using apply_bytes on ingress redirect to the 5.15-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: bpf-sockmap-fix-data-loss-caused-by-using-apply_byte.patch and it can be found in the queue-5.15 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. commit 7191f8afdfd1b9fa87912a567481ed446dd780e5 Author: Pengcheng Yang <yangpc@xxxxxxxxxx> Date: Tue Nov 29 18:40:40 2022 +0800 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: 604326b41a6f ("bpf, sockmap: convert to generic sk_msg interface") Signed-off-by: Pengcheng Yang <yangpc@xxxxxxxxxx> Signed-off-by: Daniel Borkmann <daniel@xxxxxxxxxxxxx> Acked-by: Jakub Sitnicki <jakub@xxxxxxxxxxxxxx> Link: https://lore.kernel.org/bpf/1669718441-2654-4-git-send-email-yangpc@xxxxxxxxxx Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> diff --git a/net/ipv4/tcp_bpf.c b/net/ipv4/tcp_bpf.c index 2db868ca32af..b4b642e3de78 100644 --- a/net/ipv4/tcp_bpf.c +++ b/net/ipv4/tcp_bpf.c @@ -45,8 +45,11 @@ 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);