From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id AF2E7AD27 for ; Mon, 14 Aug 2023 10:10:17 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 88466C433C8; Mon, 14 Aug 2023 10:10:16 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1692007817; bh=bSsdTL71z4hGrSCltN3Y+AqF61F+d6Q3fdKuz/7vM9c=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=hn30rE1OHQgjLAlP5+msmRlW5EYFw0eFluVuWY4hzDe/U/9Oju19LSQzb8BQWAunu fNWN3r4A+/iA7OnJXsiDsGJIxeZzUKHrMjC3LMn9qZDI6w5PkdSyFFHJGm0Q0UeAs+ PZhpZO2nit1KP1T3pP41jPTCdr8jQgMyRXrhoTIhYh/Jfn3InFMxQgJNRMFZRgbSXi FrLXVBNPLK58102Xmle3dC42yL4QUj9048QZU/UHn1bQwh9472cqdtoazf939gq45X z0fnqLH7ppkCHbGysqAZSxvaYUmA3VNFJ2rixJ2b9xlaAw1esW9KDOOxMunq3N8zDd it/vEu5HDEpFQ== Date: Mon, 14 Aug 2023 13:10:13 +0300 From: Leon Romanovsky To: Dong Chenchen Cc: steffen.klassert@secunet.com, herbert@gondor.apana.org.au, davem@davemloft.net, edumazet@google.com, kuba@kernel.org, pabeni@redhat.com, fw@strlen.de, timo.teras@iki.fi, yuehaibing@huawei.com, weiyongjun1@huawei.com, netdev@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH net] net: xfrm: skip policies marked as dead while reinserting policies Message-ID: <20230814101013.GC3921@unreal> References: <20230814013352.2771452-1-dongchenchen2@huawei.com> <20230814070349.GA3921@unreal> Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20230814070349.GA3921@unreal> On Mon, Aug 14, 2023 at 04:58:46PM +0800, Dong Chenchen wrote: > On Mon, Aug 14, 2023 at 09:33:52AM +0800, Dong Chenchen wrote: > >> BUG: KASAN: slab-use-after-free in xfrm_policy_inexact_list_reinsert+0xb6/0x430 > >> Read of size 1 at addr ffff8881051f3bf8 by task ip/668 > >> > >> CPU: 2 PID: 668 Comm: ip Not tainted 6.5.0-rc5-00182-g25aa0bebba72-dirty #64 > >> Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.13 04/01/2014 > >> Call Trace: > >> > >> dump_stack_lvl+0x72/0xa0 > >> print_report+0xd0/0x620 > >> kasan_report+0xb6/0xf0 > >> xfrm_policy_inexact_list_reinsert+0xb6/0x430 > >> xfrm_policy_inexact_insert_node.constprop.0+0x537/0x800 > >> xfrm_policy_inexact_alloc_chain+0x23f/0x320 > >> xfrm_policy_inexact_insert+0x6b/0x590 > >> xfrm_policy_insert+0x3b1/0x480 > >> xfrm_add_policy+0x23c/0x3c0 > >> xfrm_user_rcv_msg+0x2d0/0x510 > >> netlink_rcv_skb+0x10d/0x2d0 > >> xfrm_netlink_rcv+0x49/0x60 > >> netlink_unicast+0x3fe/0x540 > >> netlink_sendmsg+0x528/0x970 > >> sock_sendmsg+0x14a/0x160 > >> ____sys_sendmsg+0x4fc/0x580 > >> ___sys_sendmsg+0xef/0x160 > >> __sys_sendmsg+0xf7/0x1b0 > >> do_syscall_64+0x3f/0x90 > >> entry_SYSCALL_64_after_hwframe+0x73/0xdd > >> > >> The root cause is: > >> > >> cpu 0 cpu1 > >> xfrm_dump_policy > >> xfrm_policy_walk > >> list_move_tail > >> xfrm_add_policy > >> ... ... > >> xfrm_policy_inexact_list_reinsert > >> list_for_each_entry_reverse > >> if (!policy->bydst_reinsert) > >> //read non-existent policy > >> xfrm_dump_policy_done > >> xfrm_policy_walk_done > >> list_del(&walk->walk.all); > >> > >> If dump_one_policy() returns err (triggered by netlink socket), > >> xfrm_policy_walk() will move walk initialized by socket to list > >> net->xfrm.policy_all. so this socket becomes visible in the global > >> policy list. The head *walk can be traversed when users add policies > >> with different prefixlen and trigger xfrm_policy node merge. > >> > >> It can be fixed by skip such "policies" with walk.dead set to 1. > > > >But where in the xfrm_dump_policy() flow, these policies are becoming to > >be walk.dead == 1? > > > >Thanks > > > user will use xfrm_dispatch[XFRM_MSG_GETPOLICY] ops to get xfrm policy. > > .start = xfrm_dump_policy_start > > xfrm_dump_policy_start() will set walk.dead to 1 by call > xfrm_policy_walk_init(). Thanks > > Thanks > >> > >> Fixes: 9cf545ebd591 ("xfrm: policy: store inexact policies in a tree ordered by destination address") > >> Fixes: 12a169e7d8f4 ("ipsec: Put dumpers on the dump list") > >> Signed-off-by: Dong Chenchen > >> --- > >> net/xfrm/xfrm_policy.c | 3 +++ > >> 1 file changed, 3 insertions(+) > >> > >> diff --git a/net/xfrm/xfrm_policy.c b/net/xfrm/xfrm_policy.c > >> index d6b405782b63..5b56faad78e0 100644 > >> --- a/net/xfrm/xfrm_policy.c > >> +++ b/net/xfrm/xfrm_policy.c > >> @@ -848,6 +848,9 @@ static void xfrm_policy_inexact_list_reinsert(struct net *net, > >> matched_d = 0; > >> > >> list_for_each_entry_reverse(policy, &net->xfrm.policy_all, walk.all) { > >> + if (policy->walk.dead) > >> + continue; > >> + > >> struct hlist_node *newpos = NULL; > >> bool matches_s, matches_d; > >> > >> -- > >> 2.25.1 > >> > >> >