From 4bf37baec807c1fa0377c26f495f04cb90ff8822 Mon Sep 17 00:00:00 2001 From: Ziyang Xuan Date: Mon, 20 Jun 2022 12:35:08 +0800 Subject: [PATCH] net/tls: fix tls_sk_proto_close executed repeatedly 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: 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: 8e0fd2340797 ("bpf: sockmap/tls, close can race with map free") Reported-by: syzbot+29c3c12f3214b85ad081@syzkaller.appspotmail.com Signed-off-by: Ziyang Xuan Signed-off-by: David S. Miller --- net/tls/tls_main.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/net/tls/tls_main.c b/net/tls/tls_main.c index da176411c1b5f..46bd5f26338bf 100644 --- a/net/tls/tls_main.c +++ b/net/tls/tls_main.c @@ -921,6 +921,9 @@ 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; -- 2.39.5