From patchwork Fri May 29 18:32:25 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Eric Dumazet X-Patchwork-Id: 218184 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=-17.4 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, 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 A2F78C433E1 for ; Fri, 29 May 2020 18:32:32 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 7A78C207BC for ; Fri, 29 May 2020 18:32:32 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="Wj63pLcI" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727039AbgE2Scb (ORCPT ); Fri, 29 May 2020 14:32:31 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:50344 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726549AbgE2Sc3 (ORCPT ); Fri, 29 May 2020 14:32:29 -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 5BA0AC03E969 for ; Fri, 29 May 2020 11:32:29 -0700 (PDT) Received: by mail-qt1-x849.google.com with SMTP id u26so3595067qtj.21 for ; Fri, 29 May 2020 11:32:29 -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=CPD6t8qyn60uaZGexPzIrN0uMFVn1hag1oBpJqZOMio=; b=Wj63pLcIVgZqFnHF2SWV8aawtVj5OcW4Rbncms5DBmv1hWNlbZHJDk45+4m3SYy0dm 9ZyiQ9tDgbCF8YRQv1SNqgASPIR/KQB29n0UdHyxC7zEQJtK9KiRxQIPkrWpWlaztuTG lQQhsmKtrOxQrQGtYqEFCpzg1NF5HKhirSJR4b72/icYuBjdwMm33ik5UYJ0eTs/gRDy PRR7ZcVHCVBA2fn8bPZdEo5mbJ6GQRbNrGeC1q1Mm0pBA5mkaKm15S5F63+9k1XdlAch MGEyPlAzbRa1aIewuOZGQh/EP7HZQ14SPMcQCVcSwyt2vD92z7jhnv0eMeQyizruCihg A6Dg== 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=CPD6t8qyn60uaZGexPzIrN0uMFVn1hag1oBpJqZOMio=; b=bH6toD2GjBMBXy+4crFCMJlJPBIsW/6Vw1PXr7IJkub0rjHlwPRHDYpWIBQsMHdSE4 h80uhWDhXztNtXmVqL4BhrrsNWLRQ2H3Xss/kpwPyropiq2gmCS++Pxec6JiKHKao/cZ 1/T7Qn3hE3hrOpCujaLcCpTbybd8Q6Nj02CMPzpstoI/WKuzULg5e8GK+ym/dXd2FXvx yM0sEQC0mSPFvZNx2kOPcF8rHhZwH0VnkUAlADFNCzkwFLvkwaykSVKgxI68jgB1th8T +O3+JF3Ib4BpM5E5dvJAdvCXvhHa/cwYh7vbPsqRPeamQIk7lc+xuvSwoqKDEKFtz4TV +/Ag== X-Gm-Message-State: AOAM531qvh9I1KlsepqzxYDd0B8TiPdRlaIXCLjpTsxt+JKc5sLqNFMH hVy2ykDHjJX9OkLI/uJtH63ERxmVtZRNKg== X-Google-Smtp-Source: ABdhPJwq+oftMciw4vHgXt35oSCPiv3eW+RqKyFgULBS02WQjoXW2KfEC1N91bmgJNAJ8Uh2xnZ+9MLPLT6TcA== X-Received: by 2002:a0c:e403:: with SMTP id o3mr9084233qvl.24.1590777148552; Fri, 29 May 2020 11:32:28 -0700 (PDT) Date: Fri, 29 May 2020 11:32:25 -0700 Message-Id: <20200529183225.150288-1-edumazet@google.com> Mime-Version: 1.0 X-Mailer: git-send-email 2.27.0.rc2.251.g90737beb825-goog Subject: [PATCH net] l2tp: add sk_family checks to l2tp_validate_socket From: Eric Dumazet To: "David S . Miller" Cc: netdev , Eric Dumazet , Eric Dumazet , James Chapman , Guillaume Nault , syzbot Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org syzbot was able to trigger a crash after using an ISDN socket and fool l2tp. Fix this by making sure the UDP socket is of the proper family. BUG: KASAN: slab-out-of-bounds in setup_udp_tunnel_sock+0x465/0x540 net/ipv4/udp_tunnel.c:78 Write of size 1 at addr ffff88808ed0c590 by task syz-executor.5/3018 CPU: 0 PID: 3018 Comm: syz-executor.5 Not tainted 5.7.0-rc6-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0x188/0x20d lib/dump_stack.c:118 print_address_description.constprop.0.cold+0xd3/0x413 mm/kasan/report.c:382 __kasan_report.cold+0x20/0x38 mm/kasan/report.c:511 kasan_report+0x33/0x50 mm/kasan/common.c:625 setup_udp_tunnel_sock+0x465/0x540 net/ipv4/udp_tunnel.c:78 l2tp_tunnel_register+0xb15/0xdd0 net/l2tp/l2tp_core.c:1523 l2tp_nl_cmd_tunnel_create+0x4b2/0xa60 net/l2tp/l2tp_netlink.c:249 genl_family_rcv_msg_doit net/netlink/genetlink.c:673 [inline] genl_family_rcv_msg net/netlink/genetlink.c:718 [inline] genl_rcv_msg+0x627/0xdf0 net/netlink/genetlink.c:735 netlink_rcv_skb+0x15a/0x410 net/netlink/af_netlink.c:2469 genl_rcv+0x24/0x40 net/netlink/genetlink.c:746 netlink_unicast_kernel net/netlink/af_netlink.c:1303 [inline] netlink_unicast+0x537/0x740 net/netlink/af_netlink.c:1329 netlink_sendmsg+0x882/0xe10 net/netlink/af_netlink.c:1918 sock_sendmsg_nosec net/socket.c:652 [inline] sock_sendmsg+0xcf/0x120 net/socket.c:672 ____sys_sendmsg+0x6e6/0x810 net/socket.c:2352 ___sys_sendmsg+0x100/0x170 net/socket.c:2406 __sys_sendmsg+0xe5/0x1b0 net/socket.c:2439 do_syscall_64+0xf6/0x7d0 arch/x86/entry/common.c:295 entry_SYSCALL_64_after_hwframe+0x49/0xb3 RIP: 0033:0x45ca29 Code: 0d b7 fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 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 db b6 fb ff c3 66 2e 0f 1f 84 00 00 00 00 RSP: 002b:00007effe76edc78 EFLAGS: 00000246 ORIG_RAX: 000000000000002e RAX: ffffffffffffffda RBX: 00000000004fe1c0 RCX: 000000000045ca29 RDX: 0000000000000000 RSI: 0000000020000240 RDI: 0000000000000005 RBP: 000000000078bf00 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff R13: 000000000000094e R14: 00000000004d5d00 R15: 00007effe76ee6d4 Allocated by task 3018: save_stack+0x1b/0x40 mm/kasan/common.c:49 set_track mm/kasan/common.c:57 [inline] __kasan_kmalloc mm/kasan/common.c:495 [inline] __kasan_kmalloc.constprop.0+0xbf/0xd0 mm/kasan/common.c:468 __do_kmalloc mm/slab.c:3656 [inline] __kmalloc+0x161/0x7a0 mm/slab.c:3665 kmalloc include/linux/slab.h:560 [inline] sk_prot_alloc+0x223/0x2f0 net/core/sock.c:1612 sk_alloc+0x36/0x1100 net/core/sock.c:1666 data_sock_create drivers/isdn/mISDN/socket.c:600 [inline] mISDN_sock_create+0x272/0x400 drivers/isdn/mISDN/socket.c:796 __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 Freed by task 2484: save_stack+0x1b/0x40 mm/kasan/common.c:49 set_track mm/kasan/common.c:57 [inline] kasan_set_free_info mm/kasan/common.c:317 [inline] __kasan_slab_free+0xf7/0x140 mm/kasan/common.c:456 __cache_free mm/slab.c:3426 [inline] kfree+0x109/0x2b0 mm/slab.c:3757 kvfree+0x42/0x50 mm/util.c:603 __free_fdtable+0x2d/0x70 fs/file.c:31 put_files_struct fs/file.c:420 [inline] put_files_struct+0x248/0x2e0 fs/file.c:413 exit_files+0x7e/0xa0 fs/file.c:445 do_exit+0xb04/0x2dd0 kernel/exit.c:791 do_group_exit+0x125/0x340 kernel/exit.c:894 get_signal+0x47b/0x24e0 kernel/signal.c:2739 do_signal+0x81/0x2240 arch/x86/kernel/signal.c:784 exit_to_usermode_loop+0x26c/0x360 arch/x86/entry/common.c:161 prepare_exit_to_usermode arch/x86/entry/common.c:196 [inline] syscall_return_slowpath arch/x86/entry/common.c:279 [inline] do_syscall_64+0x6b1/0x7d0 arch/x86/entry/common.c:305 entry_SYSCALL_64_after_hwframe+0x49/0xb3 The buggy address belongs to the object at ffff88808ed0c000 which belongs to the cache kmalloc-2k of size 2048 The buggy address is located 1424 bytes inside of 2048-byte region [ffff88808ed0c000, ffff88808ed0c800) The buggy address belongs to the page: page:ffffea00023b4300 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 flags: 0xfffe0000000200(slab) raw: 00fffe0000000200 ffffea0002838208 ffffea00015ba288 ffff8880aa000e00 raw: 0000000000000000 ffff88808ed0c000 0000000100000001 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff88808ed0c480: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ffff88808ed0c500: 00 00 00 fc fc fc fc fc fc fc fc fc fc fc fc fc >ffff88808ed0c580: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ^ ffff88808ed0c600: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ffff88808ed0c680: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc Fixes: 6b9f34239b00 ("l2tp: fix races in tunnel creation") Fixes: fd558d186df2 ("l2tp: Split pppol2tp patch into separate l2tp and ppp parts") Signed-off-by: Eric Dumazet Cc: James Chapman Cc: Guillaume Nault Reported-by: syzbot --- net/l2tp/l2tp_core.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/net/l2tp/l2tp_core.c b/net/l2tp/l2tp_core.c index fcb53ed1c4fb98de3d60c52542e4c4260582bf3a..6d7ef78c88af059a4cbfb5d89f32ad6d1babfe74 100644 --- a/net/l2tp/l2tp_core.c +++ b/net/l2tp/l2tp_core.c @@ -1458,6 +1458,9 @@ static int l2tp_validate_socket(const struct sock *sk, const struct net *net, if (sk->sk_type != SOCK_DGRAM) return -EPROTONOSUPPORT; + if (sk->sk_family != PF_INET && sk->sk_family != PF_INET6) + return -EPROTONOSUPPORT; + if ((encap == L2TP_ENCAPTYPE_UDP && sk->sk_protocol != IPPROTO_UDP) || (encap == L2TP_ENCAPTYPE_IP && sk->sk_protocol != IPPROTO_L2TP)) return -EPROTONOSUPPORT;