From patchwork Sat Jul 9 02:46:59 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Hawkins Jiawei X-Patchwork-Id: 12912033 X-Patchwork-Delegate: kuba@kernel.org Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id E0968CCA47B for ; Sat, 9 Jul 2022 02:47:22 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229492AbiGICrV (ORCPT ); Fri, 8 Jul 2022 22:47:21 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:60928 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229452AbiGICrT (ORCPT ); Fri, 8 Jul 2022 22:47:19 -0400 Received: from mail-oa1-x34.google.com (mail-oa1-x34.google.com [IPv6:2001:4860:4864:20::34]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 7D86A78211; Fri, 8 Jul 2022 19:47:17 -0700 (PDT) Received: by mail-oa1-x34.google.com with SMTP id 586e51a60fabf-10bffc214ffso883702fac.1; Fri, 08 Jul 2022 19:47:17 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=6BGKZlQ2XgPXargm2Wo7BrmlFidyoAhj3y0XxGiXJm0=; b=JykCDruTogaWu6LLxNnu8Hd8UnhoJw4HRRvDIpLjJ3ArGe9cb7eNVrYGXxOlZhf9HH pNklBJZxZ9Gy29spJTJqCHrIDxvRTBr1RSvwrqhV9UE9qvzQsf6Z4GN885ZZHNiRFmmA fqLPZ4oaPvYSZINiq45OiSReXqi+isfQ/BkcqEqqNnRaFEqMj/H2x5c/dnWhmUS9UCjr XxUmLujFcDkNylO/H6/dwgjdP2R3DweSb3MShtbRT6m4DfROYxmJy0w9YxTlnic5PNKc C8UNMkn6QSIyAaxy9mHISrYyUojjBYxmmPBqNeMbgBpD/+Bbux/0oH011IRwfZae8dPq J04Q== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=6BGKZlQ2XgPXargm2Wo7BrmlFidyoAhj3y0XxGiXJm0=; b=LoNeawgfiTLmTfnjjtI7P5Gj9KqGHSR0YY5AjEJynqSTgOuiYH5MFI8N1RwwIRL2+A JiBBRu0lleUnBqsRwykabJxlS6QxcvPjzz/DhpZEoVlPoRkUN+PQFEdp9i+g4x6o6LoI X6km3bQ/5I8hlQJzeJt13oYl5DGVLdfv0Sb3ASwAQ7CqBb97QNgyXdoAThjPAXiZKNJT nJ7H1o9naglli0aMtOz3Cmzf9EzRkVardM0hjo041QliPQM9fP6QgSpKb1RUyvXP2VTb gBUhA4cfonYvBr+0pH8kpNSrDSvls+L979dKhu9RXNrtGGerMIlgUGthu8codgNjIzFV DmaA== X-Gm-Message-State: AJIora++Q235eP20/mXjr7NQKr8tMKBnDd7WqUfnjF7aa0himvzr5Emm 1rQ/qgTR3zTwqDhzQ6JChDU93iqCdSbM8q1j7EFoNw== X-Google-Smtp-Source: AGRyM1vEOmXQ0e6DzN+O8R9g1l8g+u86gRu6KOjY6pNieru/kNk84RuiD7FmFu2uEYfiHCgH1y6KvA== X-Received: by 2002:a05:6870:c0ce:b0:10c:4d83:8e15 with SMTP id e14-20020a056870c0ce00b0010c4d838e15mr1624440oad.137.1657334836236; Fri, 08 Jul 2022 19:47:16 -0700 (PDT) Received: from ubuntu.lan ([136.175.179.221]) by smtp.gmail.com with ESMTPSA id u65-20020acaab44000000b0032eb81e352asm274880oie.38.2022.07.08.19.47.05 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 08 Jul 2022 19:47:15 -0700 (PDT) From: Hawkins Jiawei To: syzbot+5f26f85569bd179c18ce@syzkaller.appspotmail.com Cc: andrii@kernel.org, ast@kernel.org, borisp@nvidia.com, bpf@vger.kernel.org, daniel@iogearbox.net, davem@davemloft.net, edumazet@google.com, guwen@linux.alibaba.com, yoshfuji@linux-ipv6.org, dsahern@kernel.org, john.fastabend@gmail.com, kafai@fb.com, kgraul@linux.ibm.com, kpsingh@kernel.org, kuba@kernel.org, linux-kernel@vger.kernel.org, netdev@vger.kernel.org, pabeni@redhat.com, songliubraving@fb.com, syzkaller-bugs@googlegroups.com, yhs@fb.com, skhan@linuxfoundation.org, 18801353760@163.com, paskripkin@gmail.com, linux-kernel-mentees@lists.linuxfoundation.org Subject: [PATCH] smc: fix refcount bug in sk_psock_get (2) Date: Sat, 9 Jul 2022 10:46:59 +0800 Message-Id: <20220709024659.6671-1-yin31149@gmail.com> X-Mailer: git-send-email 2.25.1 In-Reply-To: <00000000000026328205e08cdbeb@google.com> References: <00000000000026328205e08cdbeb@google.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org X-Patchwork-Delegate: kuba@kernel.org From: hawk <18801353760@163.com> Syzkaller reportes refcount bug as follows: ------------[ cut here ]------------ refcount_t: saturated; leaking memory. WARNING: CPU: 1 PID: 3605 at lib/refcount.c:19 refcount_warn_saturate+0xf4/0x1e0 lib/refcount.c:19 Modules linked in: CPU: 1 PID: 3605 Comm: syz-executor208 Not tainted 5.18.0-syzkaller-03023-g7e062cda7d90 #0 ... Call Trace: __refcount_add_not_zero include/linux/refcount.h:163 [inline] __refcount_inc_not_zero include/linux/refcount.h:227 [inline] refcount_inc_not_zero include/linux/refcount.h:245 [inline] sk_psock_get+0x3bc/0x410 include/linux/skmsg.h:439 tls_data_ready+0x6d/0x1b0 net/tls/tls_sw.c:2091 tcp_data_ready+0x106/0x520 net/ipv4/tcp_input.c:4983 tcp_data_queue+0x25f2/0x4c90 net/ipv4/tcp_input.c:5057 tcp_rcv_state_process+0x1774/0x4e80 net/ipv4/tcp_input.c:6659 tcp_v4_do_rcv+0x339/0x980 net/ipv4/tcp_ipv4.c:1682 sk_backlog_rcv include/net/sock.h:1061 [inline] __release_sock+0x134/0x3b0 net/core/sock.c:2849 release_sock+0x54/0x1b0 net/core/sock.c:3404 inet_shutdown+0x1e0/0x430 net/ipv4/af_inet.c:909 __sys_shutdown_sock net/socket.c:2331 [inline] __sys_shutdown_sock net/socket.c:2325 [inline] __sys_shutdown+0xf1/0x1b0 net/socket.c:2343 __do_sys_shutdown net/socket.c:2351 [inline] __se_sys_shutdown net/socket.c:2349 [inline] __x64_sys_shutdown+0x50/0x70 net/socket.c:2349 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x46/0xb0 syzbot is try to setup TLS on a SMC socket. During SMC fallback process in connect syscall, kernel will sets the smc->sk.sk_socket->file->private_data to smc->clcsock in smc_switch_to_fallback(), and set smc->clcsock->sk_user_data to origin smc in smc_fback_replace_callbacks(). When syzbot makes a setsockopt syscall, its argument sockfd actually points to smc->clcsock, which is not a smc_sock type, So it won't call smc_setsockopt() in setsockopt syscall, instead it will call do_tcp_setsockopt() to setup TLS, which bypasses the fixes 734942cc4ea6, its content is shown as below > diff --git a/net/smc/af_smc.c b/net/smc/af_smc.c > index be3e80b3e27f1..5eff7cccceffc 100644 > --- a/net/smc/af_smc.c > +++ b/net/smc/af_smc.c > @@ -2161,6 +2161,9 @@ static int smc_setsockopt(struct socket *sock, > int level, int optname, > struct smc_sock *smc; > int val, rc; > > + if (level == SOL_TCP && optname == TCP_ULP) > + return -EOPNOTSUPP; > + > smc = smc_sk(sk); > > /* generic setsockopts reaching us here always apply to the > @@ -2185,7 +2188,6 @@ static int smc_setsockopt(struct socket *sock, > int level, int optname, > if (rc || smc->use_fallback) > goto out; > switch (optname) { > - case TCP_ULP: > case TCP_FASTOPEN: > case TCP_FASTOPEN_CONNECT: > case TCP_FASTOPEN_KEY: > -- Later, sk_psock_get() will treat the smc->clcsock->sk_user_data as sk_psock type, which triggers the refcnt warning. So Just disallow this setup in do_tcp_setsockopt() is OK, by checking whether sk_user_data points to a SMC socket. Reported-and-tested-by: syzbot+5f26f85569bd179c18ce@syzkaller.appspotmail.com Signed-off-by: hawk <18801353760@163.com> --- net/ipv4/tcp.c | 13 +++++++++++++ 1 file changed, 13 insertions(+) diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c index 9984d23a7f3e..a1e6cab2c748 100644 --- a/net/ipv4/tcp.c +++ b/net/ipv4/tcp.c @@ -3395,10 +3395,23 @@ static int do_tcp_setsockopt(struct sock *sk, int level, int optname, } case TCP_ULP: { char name[TCP_ULP_NAME_MAX]; + struct sock *smc_sock; if (optlen < 1) return -EINVAL; + /* SMC sk_user_data may be treated as psock, + * which triggers a refcnt warning. + */ + rcu_read_lock(); + smc_sock = rcu_dereference_sk_user_data(sk); + if (level == SOL_TCP && smc_sock && + smc_sock->__sk_common.skc_family == AF_SMC) { + rcu_read_unlock(); + return -EOPNOTSUPP; + } + rcu_read_unlock(); + val = strncpy_from_sockptr(name, optval, min_t(long, TCP_ULP_NAME_MAX - 1, optlen));