This is a note to let you know that I've just added the patch titled samples/bpf: Fix buffer overflow in tcp_basertt to the 5.4-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: samples-bpf-fix-buffer-overflow-in-tcp_basertt.patch and it can be found in the queue-5.4 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. commit 0ee82b960f4dc01a0d320e8313ba5f9117652bcd Author: Pengcheng Yang <yangpc@xxxxxxxxxx> Date: Fri May 5 16:50:58 2023 +0800 samples/bpf: Fix buffer overflow in tcp_basertt [ Upstream commit f4dea9689c5fea3d07170c2cb0703e216f1a0922 ] Using sizeof(nv) or strlen(nv)+1 is correct. Fixes: c890063e4404 ("bpf: sample BPF_SOCKET_OPS_BASE_RTT program") Signed-off-by: Pengcheng Yang <yangpc@xxxxxxxxxx> Link: https://lore.kernel.org/r/1683276658-2860-1-git-send-email-yangpc@xxxxxxxxxx Signed-off-by: Alexei Starovoitov <ast@xxxxxxxxxx> Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> diff --git a/samples/bpf/tcp_basertt_kern.c b/samples/bpf/tcp_basertt_kern.c index 9dba48c2b9207..66dd58f78d528 100644 --- a/samples/bpf/tcp_basertt_kern.c +++ b/samples/bpf/tcp_basertt_kern.c @@ -47,7 +47,7 @@ int bpf_basertt(struct bpf_sock_ops *skops) case BPF_SOCK_OPS_BASE_RTT: n = bpf_getsockopt(skops, SOL_TCP, TCP_CONGESTION, cong, sizeof(cong)); - if (!n && !__builtin_memcmp(cong, nv, sizeof(nv)+1)) { + if (!n && !__builtin_memcmp(cong, nv, sizeof(nv))) { /* Set base_rtt to 80us */ rv = 80; } else if (n) {