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 C6EF315CAE for ; Tue, 8 Nov 2022 14:01:15 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id F0013C433C1; Tue, 8 Nov 2022 14:01:14 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1667916075; bh=J0lO1Hkm9OQk30DzFUC7aVCH65HlCZ87jqMokj+da5U=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=ZC19zvtOwxLdQi5X8r+aFtjtyUcXtmL1VXy40fJCorOtP6cOzpmlbT6LOaTHSBZMN 1QdIhPtaEqnMQgSAqi07gkTi1vrAp9fXmUPG+mm+2N2VLUFuLUr22k3On+4yTlFeup SlLs/bXaYtaaUQk4jbs9KZNRLdPe76s5su+yHUZU= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Chen Zhongjin , Eric Dumazet , "Denis V. Lunev" , Jakub Kicinski , Sasha Levin Subject: [PATCH 5.15 056/144] net, neigh: Fix null-ptr-deref in neigh_table_clear() Date: Tue, 8 Nov 2022 14:38:53 +0100 Message-Id: <20221108133347.634553697@linuxfoundation.org> X-Mailer: git-send-email 2.38.1 In-Reply-To: <20221108133345.346704162@linuxfoundation.org> References: <20221108133345.346704162@linuxfoundation.org> User-Agent: quilt/0.67 Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit From: Chen Zhongjin [ Upstream commit f8017317cb0b279b8ab98b0f3901a2e0ac880dad ] When IPv6 module gets initialized but hits an error in the middle, kenel panic with: KASAN: null-ptr-deref in range [0x0000000000000598-0x000000000000059f] CPU: 1 PID: 361 Comm: insmod Hardware name: QEMU Standard PC (i440FX + PIIX, 1996) RIP: 0010:__neigh_ifdown.isra.0+0x24b/0x370 RSP: 0018:ffff888012677908 EFLAGS: 00000202 ... Call Trace: neigh_table_clear+0x94/0x2d0 ndisc_cleanup+0x27/0x40 [ipv6] inet6_init+0x21c/0x2cb [ipv6] do_one_initcall+0xd3/0x4d0 do_init_module+0x1ae/0x670 ... Kernel panic - not syncing: Fatal exception When ipv6 initialization fails, it will try to cleanup and calls: neigh_table_clear() neigh_ifdown(tbl, NULL) pneigh_queue_purge(&tbl->proxy_queue, dev_net(dev == NULL)) # dev_net(NULL) triggers null-ptr-deref. Fix it by passing NULL to pneigh_queue_purge() in neigh_ifdown() if dev is NULL, to make kernel not panic immediately. Fixes: 66ba215cb513 ("neigh: fix possible DoS due to net iface start/stop loop") Signed-off-by: Chen Zhongjin Reviewed-by: Eric Dumazet Reviewed-by: Denis V. Lunev Link: https://lore.kernel.org/r/20221101121552.21890-1-chenzhongjin@huawei.com Signed-off-by: Jakub Kicinski Signed-off-by: Sasha Levin --- net/core/neighbour.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/net/core/neighbour.c b/net/core/neighbour.c index b3556c5c1c08..0e22ecb46977 100644 --- a/net/core/neighbour.c +++ b/net/core/neighbour.c @@ -372,7 +372,7 @@ static int __neigh_ifdown(struct neigh_table *tbl, struct net_device *dev, write_lock_bh(&tbl->lock); neigh_flush_dev(tbl, dev, skip_perm); pneigh_ifdown_and_unlock(tbl, dev); - pneigh_queue_purge(&tbl->proxy_queue, dev_net(dev)); + pneigh_queue_purge(&tbl->proxy_queue, dev ? dev_net(dev) : NULL); if (skb_queue_empty_lockless(&tbl->proxy_queue)) del_timer_sync(&tbl->proxy_timer); return 0; -- 2.35.1