This is a note to let you know that I've just added the patch titled net/tls: fix tls_sk_proto_close executed repeatedly 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: net-tls-fix-tls_sk_proto_close-executed-repeatedly.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 57172a0711d1002ec506f2a96ac3ab4ebe09aa60 Author: Ziyang Xuan <william.xuanziyang@xxxxxxxxxx> Date: Mon Jun 20 12:35:08 2022 +0800 net/tls: fix tls_sk_proto_close executed repeatedly [ Upstream commit 69135c572d1f84261a6de2a1268513a7e71753e2 ] After setting the sock ktls, update ctx->sk_proto to sock->sk_prot by tls_update(), so now ctx->sk_proto->close is tls_sk_proto_close(). When close the sock, tls_sk_proto_close() is called for sock->sk_prot->close is tls_sk_proto_close(). But ctx->sk_proto->close() will be executed later in tls_sk_proto_close(). Thus tls_sk_proto_close() executed repeatedly occurred. That will trigger the following bug. ================================================================= KASAN: null-ptr-deref in range [0x0000000000000010-0x0000000000000017] RIP: 0010:tls_sk_proto_close+0xd8/0xaf0 net/tls/tls_main.c:306 Call Trace: <TASK> tls_sk_proto_close+0x356/0xaf0 net/tls/tls_main.c:329 inet_release+0x12e/0x280 net/ipv4/af_inet.c:428 __sock_release+0xcd/0x280 net/socket.c:650 sock_close+0x18/0x20 net/socket.c:1365 Updating a proto which is same with sock->sk_prot is incorrect. Add proto and sock->sk_prot equality check at the head of tls_update() to fix it. Fixes: 95fa145479fb ("bpf: sockmap/tls, close can race with map free") Reported-by: syzbot+29c3c12f3214b85ad081@xxxxxxxxxxxxxxxxxxxxxxxxx Signed-off-by: Ziyang Xuan <william.xuanziyang@xxxxxxxxxx> Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx> Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> diff --git a/net/tls/tls_main.c b/net/tls/tls_main.c index 7aba4ee77aba..df9177d96f7f 100644 --- a/net/tls/tls_main.c +++ b/net/tls/tls_main.c @@ -803,6 +803,9 @@ static void tls_update(struct sock *sk, struct proto *p, { struct tls_context *ctx; + if (sk->sk_prot == p) + return; + ctx = tls_get_ctx(sk); if (likely(ctx)) { ctx->sk_write_space = write_space;