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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 6215FC433FE for ; Wed, 5 Oct 2022 19:08:17 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230040AbiJETIQ (ORCPT ); Wed, 5 Oct 2022 15:08:16 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:51200 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229735AbiJETIO (ORCPT ); Wed, 5 Oct 2022 15:08:14 -0400 Received: from wout3-smtp.messagingengine.com (wout3-smtp.messagingengine.com [64.147.123.19]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 8059678214 for ; Wed, 5 Oct 2022 12:08:12 -0700 (PDT) Received: from compute2.internal (compute2.nyi.internal [10.202.2.46]) by mailout.west.internal (Postfix) with ESMTP id B29853200B6D; Wed, 5 Oct 2022 15:08:08 -0400 (EDT) Received: from mailfrontend1 ([10.202.2.162]) by compute2.internal (MEProxy); Wed, 05 Oct 2022 15:08:09 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d= messagingengine.com; h=cc:cc:content-type:date:date:feedback-id :feedback-id:from:from:in-reply-to:in-reply-to:message-id :mime-version:references:reply-to:sender:subject:subject:to:to :x-me-proxy:x-me-proxy:x-me-sender:x-me-sender:x-sasl-enc; s= fm2; t=1664996888; x=1665083288; bh=bWBFvLjjXU2QoI/WeY/XeVHjKS8k uKEnhsSosIDH3hk=; b=NXhvnjZUbWVH6PJIP4g4P6w2lCWUkmKF/GnknFO2SX0Y nKxyiNnz4SqhoR/fmlLuWXsUXpCfOQp8FKGR7Kqcy6DRzXqFMaQmYqZsRnq5cycj E39qK4H5rvJQf2BFvtlyCR4pJe+YvnTReX61RdfC/uPuybuwUzC9jC4Oddtfh0Rl QRTWoMVhcPzxhgWFI3uhEPT/waB0KrdNMrsx0tb11nOSaZp1rRjVOlJ/2y3xA3KC txcl6VaYzo6j/X+/vcUHAt5X/fqoqpml2n9is+6pYE76aB3DfdtU2sG2tBok37Th szZN2mGZhx1WGDcYAhgZkFjCnnUzTS+3YiggdgpNvw== X-ME-Sender: X-ME-Received: X-ME-Proxy-Cause: gggruggvucftvghtrhhoucdtuddrgedvfedrfeeifedgudefvdcutefuodetggdotefrod ftvfcurfhrohhfihhlvgemucfhrghsthforghilhdpqfgfvfdpuffrtefokffrpgfnqfgh necuuegrihhlohhuthemuceftddtnecusecvtfgvtghiphhivghnthhsucdlqddutddtmd enucfjughrpeffhffvvefukfhfgggtuggjsehttdertddttddvnecuhfhrohhmpefkugho ucfutghhihhmmhgvlhcuoehiughoshgthhesihguohhstghhrdhorhhgqeenucggtffrrg htthgvrhhnpedtjeefhefgteevtdejfeeutdduhffhjeeiieffiefhhfekveefteeifffh kedtudenucffohhmrghinhepnhgvgihthhhophhsrdhshhenucevlhhushhtvghrufhiii gvpedtnecurfgrrhgrmhepmhgrihhlfhhrohhmpehiughoshgthhesihguohhstghhrdho rhhg X-ME-Proxy: Feedback-ID: i494840e7:Fastmail Received: by mail.messagingengine.com (Postfix) with ESMTPA; Wed, 5 Oct 2022 15:08:07 -0400 (EDT) Date: Wed, 5 Oct 2022 22:08:03 +0300 From: Ido Schimmel To: David Ahern Cc: kuba@kernel.org, davem@davemloft.net, pabeni@redhat.com, netdev@vger.kernel.org, Gwangun Jung Subject: Re: [PATCH net] ipv4: Handle attempt to delete multipath route when fib_info contains an nh reference Message-ID: References: <20221005181257.8897-1-dsahern@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20221005181257.8897-1-dsahern@kernel.org> Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org On Wed, Oct 05, 2022 at 12:12:57PM -0600, David Ahern wrote: > Gwangun Jung reported a slab-out-of-bounds access in fib_nh_match: > fib_nh_match+0xf98/0x1130 linux-6.0-rc7/net/ipv4/fib_semantics.c:961 > fib_table_delete+0x5f3/0xa40 linux-6.0-rc7/net/ipv4/fib_trie.c:1753 > inet_rtm_delroute+0x2b3/0x380 linux-6.0-rc7/net/ipv4/fib_frontend.c:874 > > Separate nexthop objects are mutually exclusive with the legacy > multipath spec. Fix fib_nh_match to return if the config for the > to be deleted route contains a multipath spec while the fib_info > is using a nexthop object. Cool bug... Managed to reproduce with: # ip nexthop add id 1 blackhole # ip route add 192.0.2.0/24 nhid 1 # ip route del 192.0.2.0/24 nexthop via 198.51.100.1 nexthop via 198.51.100.2 Maybe add to tools/testing/selftests/net/fib_nexthops.sh ? Checked IPv6 and I don't think we can hit it there, but I will double check tomorrow morning. > > Fixes: 493ced1ac47c ("ipv4: Allow routes to use nexthop objects") > Reported-by: Gwangun Jung > Signed-off-by: David Ahern > --- > net/ipv4/fib_semantics.c | 4 ++++ > 1 file changed, 4 insertions(+) > > diff --git a/net/ipv4/fib_semantics.c b/net/ipv4/fib_semantics.c > index 2dc97583d279..17caa73f57e6 100644 > --- a/net/ipv4/fib_semantics.c > +++ b/net/ipv4/fib_semantics.c > @@ -926,6 +926,10 @@ int fib_nh_match(struct net *net, struct fib_config *cfg, struct fib_info *fi, > if (!cfg->fc_mp) > return 0; > > + /* multipath spec and nexthop id are mutually exclusive */ > + if (fi->nh) > + return 1; > + > rtnh = cfg->fc_mp; > remaining = cfg->fc_mp_len; There is already such a check above for the non-multipath check, maybe we can just move it up to cover both cases? Something like: diff --git a/net/ipv4/fib_semantics.c b/net/ipv4/fib_semantics.c index 2dc97583d279..e9a7f70a54df 100644 --- a/net/ipv4/fib_semantics.c +++ b/net/ipv4/fib_semantics.c @@ -888,13 +888,13 @@ int fib_nh_match(struct net *net, struct fib_config *cfg, struct fib_info *fi, return 1; } + /* cannot match on nexthop object attributes */ + if (fi->nh) + return 1; + if (cfg->fc_oif || cfg->fc_gw_family) { struct fib_nh *nh; - /* cannot match on nexthop object attributes */ - if (fi->nh) - return 1; - nh = fib_info_nh(fi, 0); if (cfg->fc_encap) { if (fib_encap_match(net, cfg->fc_encap_type,