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=-8.8 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT 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 25464C43613 for ; Thu, 20 Jun 2019 09:10:48 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id ED2DC2080C for ; Thu, 20 Jun 2019 09:10:47 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=messagingengine.com header.i=@messagingengine.com header.b="BerD+yFL" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726072AbfFTJKq (ORCPT ); Thu, 20 Jun 2019 05:10:46 -0400 Received: from out3-smtp.messagingengine.com ([66.111.4.27]:43187 "EHLO out3-smtp.messagingengine.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725912AbfFTJKq (ORCPT ); Thu, 20 Jun 2019 05:10:46 -0400 Received: from compute3.internal (compute3.nyi.internal [10.202.2.43]) by mailout.nyi.internal (Postfix) with ESMTP id A5C90220FF; Thu, 20 Jun 2019 05:10:45 -0400 (EDT) Received: from mailfrontend1 ([10.202.2.162]) by compute3.internal (MEProxy); Thu, 20 Jun 2019 05:10:45 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d= messagingengine.com; h=cc:content-transfer-encoding:date:from :message-id:mime-version:subject:to:x-me-proxy:x-me-proxy :x-me-sender:x-me-sender:x-sasl-enc; s=fm3; bh=oRl5xgdcfwFpUlWb7 1E59rZuG19VnJd3U4SuoJGWO1I=; b=BerD+yFLqPD9xjM9JK8tIwsbR1JtHXnif mvfaXN/Knaw8sRiqkq9KRSGfQMvHwJQQKK8xDjCG5tJugPfmo3LJXbXw5+vuDUKs +qHiKqn6HHDNH5MxteWpVC6Mfm7DyMW/NwlGqbN0GaTsxnw7vxDopnxm5D4R3wb8 PwXJNBmvJfpxd4dw/Y0dI2J7ZFyL6eJWaEfFu8TIBMWB/rNaku/yLOKs/aPy0cwq xLec9nu24QPvDUtVZirW6xxo2z058jsWPSt2/lH+XILJxM9ydHNzDqNbISfJ2bSF 31H8sUg5yXqbk728R94S/yqlzogqxSMF6Oq2bMR/5DAT/9fGHraug== X-ME-Sender: X-ME-Proxy-Cause: gggruggvucftvghtrhhoucdtuddrgeduvddrtdeggddugecutefuodetggdotefrodftvf curfhrohhfihhlvgemucfhrghsthforghilhdpqfgfvfdpuffrtefokffrpgfnqfghnecu uegrihhlohhuthemuceftddtnecunecujfgurhephffvufffkffoggfgsedtkeertdertd dtnecuhfhrohhmpefkughoucfutghhihhmmhgvlhcuoehiughoshgthhesihguohhstghh rdhorhhgqeenucfkphepudelfedrgeejrdduieehrddvhedunecurfgrrhgrmhepmhgrih hlfhhrohhmpehiughoshgthhesihguohhstghhrdhorhhgnecuvehluhhsthgvrhfuihii vgeptd X-ME-Proxy: Received: from splinter.mtl.com (unknown [193.47.165.251]) by mail.messagingengine.com (Postfix) with ESMTPA id 787FC80068; Thu, 20 Jun 2019 05:10:43 -0400 (EDT) From: Ido Schimmel To: netdev@vger.kernel.org Cc: davem@davemloft.net, dsahern@gmail.com, mlxsw@mellanox.com, Ido Schimmel Subject: [PATCH net-next v2] ipv6: Error when route does not have any valid nexthops Date: Thu, 20 Jun 2019 12:10:21 +0300 Message-Id: <20190620091021.18210-1-idosch@idosch.org> X-Mailer: git-send-email 2.20.1 MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org From: Ido Schimmel When user space sends invalid information in RTA_MULTIPATH, the nexthop list in ip6_route_multipath_add() is empty and 'rt_notif' is set to NULL. The code that emits the in-kernel notifications does not check for this condition, which results in a NULL pointer dereference [1]. Fix this by bailing earlier in the function if the parsed nexthop list is empty. This is consistent with the corresponding IPv4 code. v2: * Check if parsed nexthop list is empty and bail with extack set [1] kasan: CONFIG_KASAN_INLINE enabled kasan: GPF could be caused by NULL-ptr deref or user memory access general protection fault: 0000 [#1] PREEMPT SMP KASAN CPU: 0 PID: 9190 Comm: syz-executor149 Not tainted 5.2.0-rc5+ #38 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 RIP: 0010:call_fib6_multipath_entry_notifiers+0xd1/0x1a0 net/ipv6/ip6_fib.c:396 Code: 8b b5 30 ff ff ff 48 c7 85 68 ff ff ff 00 00 00 00 48 c7 85 70 ff ff ff 00 00 00 00 89 45 88 4c 89 e0 48 c1 e8 03 4c 89 65 80 <42> 80 3c 28 00 0f 85 9a 00 00 00 48 b8 00 00 00 00 00 fc ff df 4d RSP: 0018:ffff88809788f2c0 EFLAGS: 00010246 RAX: 0000000000000000 RBX: 1ffff11012f11e59 RCX: 00000000ffffffff RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000 RBP: ffff88809788f390 R08: ffff88809788f8c0 R09: 000000000000000c R10: ffff88809788f5d8 R11: ffff88809788f527 R12: 0000000000000000 R13: dffffc0000000000 R14: ffff88809788f8c0 R15: ffffffff89541d80 FS: 000055555632c880(0000) GS:ffff8880ae800000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000020000080 CR3: 000000009ba7c000 CR4: 00000000001406f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: ip6_route_multipath_add+0xc55/0x1490 net/ipv6/route.c:5094 inet6_rtm_newroute+0xed/0x180 net/ipv6/route.c:5208 rtnetlink_rcv_msg+0x463/0xb00 net/core/rtnetlink.c:5219 netlink_rcv_skb+0x177/0x450 net/netlink/af_netlink.c:2477 rtnetlink_rcv+0x1d/0x30 net/core/rtnetlink.c:5237 netlink_unicast_kernel net/netlink/af_netlink.c:1302 [inline] netlink_unicast+0x531/0x710 net/netlink/af_netlink.c:1328 netlink_sendmsg+0x8ae/0xd70 net/netlink/af_netlink.c:1917 sock_sendmsg_nosec net/socket.c:646 [inline] sock_sendmsg+0xd7/0x130 net/socket.c:665 ___sys_sendmsg+0x803/0x920 net/socket.c:2286 __sys_sendmsg+0x105/0x1d0 net/socket.c:2324 __do_sys_sendmsg net/socket.c:2333 [inline] __se_sys_sendmsg net/socket.c:2331 [inline] __x64_sys_sendmsg+0x78/0xb0 net/socket.c:2331 do_syscall_64+0xfd/0x680 arch/x86/entry/common.c:301 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x4401f9 Code: 18 89 d0 c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 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 fb 13 fc ff c3 66 2e 0f 1f 84 00 00 00 00 RSP: 002b:00007ffc09fd0028 EFLAGS: 00000246 ORIG_RAX: 000000000000002e RAX: ffffffffffffffda RBX: 00000000004002c8 RCX: 00000000004401f9 RDX: 0000000000000000 RSI: 0000000020000080 RDI: 0000000000000003 RBP: 00000000006ca018 R08: 0000000000000000 R09: 00000000004002c8 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000401a80 R13: 0000000000401b10 R14: 0000000000000000 R15: 0000000000000000 Reported-by: syzbot+382566d339d52cd1a204@syzkaller.appspotmail.com Fixes: ebee3cad835f ("ipv6: Add IPv6 multipath notifications for add / replace") Signed-off-by: Ido Schimmel --- net/ipv6/route.c | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/net/ipv6/route.c b/net/ipv6/route.c index c4d285fe0adc..891c8cd27712 100644 --- a/net/ipv6/route.c +++ b/net/ipv6/route.c @@ -5043,6 +5043,12 @@ static int ip6_route_multipath_add(struct fib6_config *cfg, rtnh = rtnh_next(rtnh, &remaining); } + if (list_empty(&rt6_nh_list)) { + NL_SET_ERR_MSG(extack, + "Invalid nexthop configuration - no valid nexthops"); + return -EINVAL; + } + /* for add and replace send one notification with all nexthops. * Skip the notification in fib6_add_rt2node and send one with * the full route when done -- 2.20.1