From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-14.6 required=3.0 tests=DKIMWL_WL_MED,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, UNWANTED_LANGUAGE_BODY,USER_AGENT_GIT,USER_IN_DEF_DKIM_WL autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 45632C433DF for ; Fri, 29 May 2020 18:21:04 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 1E6382067B for ; Fri, 29 May 2020 18:21:04 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="Zf2VtiKq" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726970AbgE2SVC (ORCPT ); Fri, 29 May 2020 14:21:02 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:48490 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726829AbgE2SVA (ORCPT ); Fri, 29 May 2020 14:21:00 -0400 Received: from mail-qt1-x849.google.com (mail-qt1-x849.google.com [IPv6:2607:f8b0:4864:20::849]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id B9564C03E969 for ; Fri, 29 May 2020 11:21:00 -0700 (PDT) Received: by mail-qt1-x849.google.com with SMTP id o11so3551417qti.23 for ; Fri, 29 May 2020 11:21:00 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=date:message-id:mime-version:subject:from:to:cc; bh=YQXt9ixoJWg9/UZFOVUySn0DN4xcjyeWmpvRc+UHhqw=; b=Zf2VtiKqknfVFWRWV86k7fYj5XrujlYRmAPvYoYYwCnnumv1dlLKMzdomOfrs7p8bU g6z+lb9e2UJO3Pndk3A4J+FoW+v8mtSBD6DBChlJWQxSSo0u8YsZTwEc9tqlGDkUinvz LyVWMQh3afSGmUiZACcn5L8VREwbdCr8Ib1kL4ofYbFkHrnso9Gnces1yW3y8sqULElr 3sm7dwWaqA5RN88HuARPik27WPDUANWqQ7exmBezagxKFWCi5N9cCiLXPaYNB5I5uNZ9 Cu1iwF1ACjbSwlwW7mEu0KbaPw+OIx9qh6bP61i64Xfetv4dzHlo+oAn2SECwIPubnIa G56g== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:message-id:mime-version:subject:from:to:cc; bh=YQXt9ixoJWg9/UZFOVUySn0DN4xcjyeWmpvRc+UHhqw=; b=iDnh8kwL1r78/oKdU66MCOjWPiv6TkQdNyiXbEP+wqfZt0bEjhqwKG6FPzBPknKPO4 DEhZPEYvF2HruPtiSj/APyDPGJ6aQOHSYTI2IwdZMlkoWMleUSbqqN6tBn5iSorViYya FMiXwpUQJwAtNQUuPQnBg169JEc6EDfGWHVxeelc3Woos4SBXDaj/KIRR1LH+Jbns8Bp WtKa+V/tnxk0gZzix2W+knw9+xEJlkR3Mesx1qPpOT/ztUyVtaMT91MvOe9BK7vgLLGY KKbyKQKfC4XsspKtkbBeaiSwAT9YqoBG98e9O6TfuMZSciK55yj25RmvKYFeEb7PeVep 1OGA== X-Gm-Message-State: AOAM531g5i2RZaquN/2sZX9YydJfLZrgkRbJwkyW7V7vwERAw6YSmSvp oH89Iv+4RZz63qsHEPwWWkGnUCbUPJSaNQ== X-Google-Smtp-Source: ABdhPJw2C0Sml25zoSGiorDhtVmBEHLvP0ShYCtXQXpYtT9lDszbGQcB2NGyJ0tDnA99Wcmi/ILpJkrOhn83YA== X-Received: by 2002:a05:6214:6a1:: with SMTP id s1mr9574768qvz.46.1590776459906; Fri, 29 May 2020 11:20:59 -0700 (PDT) Date: Fri, 29 May 2020 11:20:53 -0700 Message-Id: <20200529182053.134014-1-edumazet@google.com> Mime-Version: 1.0 X-Mailer: git-send-email 2.27.0.rc2.251.g90737beb825-goog Subject: [PATCH v2 net] l2tp: do not use inet_hash()/inet_unhash() From: Eric Dumazet To: "David S . Miller" Cc: netdev , Eric Dumazet , Eric Dumazet , James Chapman , Andrii Nakryiko , syzbot+3610d489778b57cc8031@syzkaller.appspotmail.com Content-Type: text/plain; charset="UTF-8" Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org syzbot recently found a way to crash the kernel [1] Issue here is that inet_hash() & inet_unhash() are currently only meant to be used by TCP & DCCP, since only these protocols provide the needed hashinfo pointer. L2TP uses a single list (instead of a hash table) This old bug became an issue after commit 610236587600 ("bpf: Add new cgroup attach type to enable sock modifications") since after this commit, sk_common_release() can be called while the L2TP socket is still considered 'hashed'. general protection fault, probably for non-canonical address 0xdffffc0000000001: 0000 [#1] PREEMPT SMP KASAN KASAN: null-ptr-deref in range [0x0000000000000008-0x000000000000000f] CPU: 0 PID: 7063 Comm: syz-executor654 Not tainted 5.7.0-rc6-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 RIP: 0010:inet_unhash+0x11f/0x770 net/ipv4/inet_hashtables.c:600 Code: 03 0f b6 04 02 84 c0 74 08 3c 03 0f 8e dd 04 00 00 48 8d 7d 08 44 8b 73 08 48 b8 00 00 00 00 00 fc ff df 48 89 fa 48 c1 ea 03 <80> 3c 02 00 0f 85 55 05 00 00 48 8d 7d 14 4c 8b 6d 08 48 b8 00 00 RSP: 0018:ffffc90001777d30 EFLAGS: 00010202 RAX: dffffc0000000000 RBX: ffff88809a6df940 RCX: ffffffff8697c242 RDX: 0000000000000001 RSI: ffffffff8697c251 RDI: 0000000000000008 RBP: 0000000000000000 R08: ffff88809f3ae1c0 R09: fffffbfff1514cc1 R10: ffffffff8a8a6607 R11: fffffbfff1514cc0 R12: ffff88809a6df9b0 R13: 0000000000000007 R14: 0000000000000000 R15: ffffffff873a4d00 FS: 0000000001d2b880(0000) GS:ffff8880ae600000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00000000006cd090 CR3: 000000009403a000 CR4: 00000000001406f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: sk_common_release+0xba/0x370 net/core/sock.c:3210 inet_create net/ipv4/af_inet.c:390 [inline] inet_create+0x966/0xe00 net/ipv4/af_inet.c:248 __sock_create+0x3cb/0x730 net/socket.c:1428 sock_create net/socket.c:1479 [inline] __sys_socket+0xef/0x200 net/socket.c:1521 __do_sys_socket net/socket.c:1530 [inline] __se_sys_socket net/socket.c:1528 [inline] __x64_sys_socket+0x6f/0xb0 net/socket.c:1528 do_syscall_64+0xf6/0x7d0 arch/x86/entry/common.c:295 entry_SYSCALL_64_after_hwframe+0x49/0xb3 RIP: 0033:0x441e29 Code: e8 fc b3 02 00 48 83 c4 18 c3 0f 1f 80 00 00 00 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 0f 83 eb 08 fc ff c3 66 2e 0f 1f 84 00 00 00 00 RSP: 002b:00007ffdce184148 EFLAGS: 00000246 ORIG_RAX: 0000000000000029 RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 0000000000441e29 RDX: 0000000000000073 RSI: 0000000000000002 RDI: 0000000000000002 RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 0000000000402c30 R14: 0000000000000000 R15: 0000000000000000 Modules linked in: ---[ end trace 23b6578228ce553e ]--- RIP: 0010:inet_unhash+0x11f/0x770 net/ipv4/inet_hashtables.c:600 Code: 03 0f b6 04 02 84 c0 74 08 3c 03 0f 8e dd 04 00 00 48 8d 7d 08 44 8b 73 08 48 b8 00 00 00 00 00 fc ff df 48 89 fa 48 c1 ea 03 <80> 3c 02 00 0f 85 55 05 00 00 48 8d 7d 14 4c 8b 6d 08 48 b8 00 00 RSP: 0018:ffffc90001777d30 EFLAGS: 00010202 RAX: dffffc0000000000 RBX: ffff88809a6df940 RCX: ffffffff8697c242 RDX: 0000000000000001 RSI: ffffffff8697c251 RDI: 0000000000000008 RBP: 0000000000000000 R08: ffff88809f3ae1c0 R09: fffffbfff1514cc1 R10: ffffffff8a8a6607 R11: fffffbfff1514cc0 R12: ffff88809a6df9b0 R13: 0000000000000007 R14: 0000000000000000 R15: ffffffff873a4d00 FS: 0000000001d2b880(0000) GS:ffff8880ae600000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00000000006cd090 CR3: 000000009403a000 CR4: 00000000001406f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Fixes: 0d76751fad77 ("l2tp: Add L2TPv3 IP encapsulation (no UDP) support") Signed-off-by: Eric Dumazet Cc: James Chapman Cc: Andrii Nakryiko Reported-by: syzbot+3610d489778b57cc8031@syzkaller.appspotmail.com --- v2: do not try to share a common unhash() method between IPv4 and IPv6 net/l2tp/l2tp_ip.c | 29 ++++++++++++++++++++++------- net/l2tp/l2tp_ip6.c | 30 ++++++++++++++++++++++-------- 2 files changed, 44 insertions(+), 15 deletions(-) diff --git a/net/l2tp/l2tp_ip.c b/net/l2tp/l2tp_ip.c index 0d7c887a2b75db65afba7955a2bf9572a6a37786..955662a6dee754478da0f8ac95d41a787339242b 100644 --- a/net/l2tp/l2tp_ip.c +++ b/net/l2tp/l2tp_ip.c @@ -20,7 +20,6 @@ #include #include #include -#include #include #include #include @@ -209,15 +208,31 @@ static int l2tp_ip_recv(struct sk_buff *skb) return 0; } +static int l2tp_ip_hash(struct sock *sk) +{ + if (sk_unhashed(sk)) { + write_lock_bh(&l2tp_ip_lock); + sk_add_node(sk, &l2tp_ip_table); + write_unlock_bh(&l2tp_ip_lock); + } + return 0; +} + +static void l2tp_ip_unhash(struct sock *sk) +{ + if (sk_unhashed(sk)) + return; + write_lock_bh(&l2tp_ip_lock); + sk_del_node_init(sk); + write_unlock_bh(&l2tp_ip_lock); +} + static int l2tp_ip_open(struct sock *sk) { /* Prevent autobind. We don't have ports. */ inet_sk(sk)->inet_num = IPPROTO_L2TP; - write_lock_bh(&l2tp_ip_lock); - sk_add_node(sk, &l2tp_ip_table); - write_unlock_bh(&l2tp_ip_lock); - + l2tp_ip_hash(sk); return 0; } @@ -594,8 +609,8 @@ static struct proto l2tp_ip_prot = { .sendmsg = l2tp_ip_sendmsg, .recvmsg = l2tp_ip_recvmsg, .backlog_rcv = l2tp_ip_backlog_recv, - .hash = inet_hash, - .unhash = inet_unhash, + .hash = l2tp_ip_hash, + .unhash = l2tp_ip_unhash, .obj_size = sizeof(struct l2tp_ip_sock), #ifdef CONFIG_COMPAT .compat_setsockopt = compat_ip_setsockopt, diff --git a/net/l2tp/l2tp_ip6.c b/net/l2tp/l2tp_ip6.c index d148766f40d117c50fc28092173d3686428d1dfc..0fa694bd3f6a992518cab05feb8922fbf94d9829 100644 --- a/net/l2tp/l2tp_ip6.c +++ b/net/l2tp/l2tp_ip6.c @@ -20,8 +20,6 @@ #include #include #include -#include -#include #include #include #include @@ -222,15 +220,31 @@ static int l2tp_ip6_recv(struct sk_buff *skb) return 0; } +static int l2tp_ip6_hash(struct sock *sk) +{ + if (sk_unhashed(sk)) { + write_lock_bh(&l2tp_ip6_lock); + sk_add_node(sk, &l2tp_ip6_table); + write_unlock_bh(&l2tp_ip6_lock); + } + return 0; +} + +static void l2tp_ip6_unhash(struct sock *sk) +{ + if (sk_unhashed(sk)) + return; + write_lock_bh(&l2tp_ip6_lock); + sk_del_node_init(sk); + write_unlock_bh(&l2tp_ip6_lock); +} + static int l2tp_ip6_open(struct sock *sk) { /* Prevent autobind. We don't have ports. */ inet_sk(sk)->inet_num = IPPROTO_L2TP; - write_lock_bh(&l2tp_ip6_lock); - sk_add_node(sk, &l2tp_ip6_table); - write_unlock_bh(&l2tp_ip6_lock); - + l2tp_ip6_hash(sk); return 0; } @@ -728,8 +742,8 @@ static struct proto l2tp_ip6_prot = { .sendmsg = l2tp_ip6_sendmsg, .recvmsg = l2tp_ip6_recvmsg, .backlog_rcv = l2tp_ip6_backlog_recv, - .hash = inet6_hash, - .unhash = inet_unhash, + .hash = l2tp_ip6_hash, + .unhash = l2tp_ip6_unhash, .obj_size = sizeof(struct l2tp_ip6_sock), #ifdef CONFIG_COMPAT .compat_setsockopt = compat_ipv6_setsockopt, -- 2.27.0.rc2.251.g90737beb825-goog