From patchwork Thu Oct 24 01:47:01 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Dong Chenchen X-Patchwork-Id: 13848170 X-Patchwork-Delegate: kuba@kernel.org Received: from szxga04-in.huawei.com (szxga04-in.huawei.com [45.249.212.190]) (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 C6BC52C9A; Thu, 24 Oct 2024 01:46:51 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=45.249.212.190 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1729734414; cv=none; b=tPth/FTAeOrriEIk8IyN2daTQbyp57OQSHoD8O8aMmB0tIrFmjSG7vSxKR8BdsqV/FvWh8D1c6ia/7FAKPiLsh4O5fBqlxocO826HNX/eA6yQ6Ryjabseb2ANoTWwuU7tRPjWMbCfy3WQWBON13kFYjbStMLlVDXfTJ8N+cli3g= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1729734414; c=relaxed/simple; bh=JJ3pxSuWPTEwJ9w0DNfAWH/58BCS2BCuUzUwJsNLduA=; h=From:To:CC:Subject:Date:Message-ID:MIME-Version:Content-Type; b=UgM6xyh0HZl4s+57hfsC7e+xsTPC66BEpH/IOqo1UUR48RVycKEz7i9HEu6Oxck82Pto+v5085TIB3t4gAl8r3Es17qfG9whl46FaOYGwkhCN5WNapTpHvqA5kXyo8P528lhHlEo8sCYUZOPlYpahSYVNa9CtEalJy+LBcmYW+A= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=huawei.com; spf=pass smtp.mailfrom=huawei.com; arc=none smtp.client-ip=45.249.212.190 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=huawei.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=huawei.com Received: from mail.maildlp.com (unknown [172.19.163.17]) by szxga04-in.huawei.com (SkyGuard) with ESMTP id 4XYpdW6JlWz2FbJM; Thu, 24 Oct 2024 09:45:19 +0800 (CST) Received: from kwepemd100023.china.huawei.com (unknown [7.221.188.33]) by mail.maildlp.com (Postfix) with ESMTPS id D2ACE1A0188; Thu, 24 Oct 2024 09:46:43 +0800 (CST) Received: from localhost.localdomain (10.175.104.82) by kwepemd100023.china.huawei.com (7.221.188.33) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.2.1544.11; Thu, 24 Oct 2024 09:46:42 +0800 From: Dong Chenchen To: , , , , , , , CC: , , , Dong Chenchen Subject: [PATCH net v2] net: netfilter: Fix use-after-free in get_info() Date: Thu, 24 Oct 2024 09:47:01 +0800 Message-ID: <20241024014701.2086286-1-dongchenchen2@huawei.com> X-Mailer: git-send-email 2.25.1 Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-ClientProxiedBy: dggems705-chm.china.huawei.com (10.3.19.182) To kwepemd100023.china.huawei.com (7.221.188.33) X-Patchwork-Delegate: kuba@kernel.org ip6table_nat module unload has refcnt warning for UAF. call trace is: WARNING: CPU: 1 PID: 379 at kernel/module/main.c:853 module_put+0x6f/0x80 Modules linked in: ip6table_nat(-) CPU: 1 UID: 0 PID: 379 Comm: ip6tables Not tainted 6.12.0-rc4-00047-gc2ee9f594da8-dirty #205 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.13.0-0-gf21b5a4aeb02-prebuilt.qemu.org 04/01/2014 RIP: 0010:module_put+0x6f/0x80 Call Trace: get_info+0x128/0x180 do_ip6t_get_ctl+0x6a/0x430 nf_getsockopt+0x46/0x80 ipv6_getsockopt+0xb9/0x100 rawv6_getsockopt+0x42/0x190 do_sock_getsockopt+0xaa/0x180 __sys_getsockopt+0x70/0xc0 __x64_sys_getsockopt+0x20/0x30 do_syscall_64+0xa2/0x1a0 entry_SYSCALL_64_after_hwframe+0x77/0x7f Concurrent execution of module unload and get_info() trigered the warning. The root cause is as follows: cpu0 cpu1 module_exit //mod->state = MODULE_STATE_GOING ip6table_nat_exit xt_unregister_template kfree(t) //removed from templ_list getinfo() t = xt_find_table_lock list_for_each_entry(tmpl, &xt_templates[af]...) if (strcmp(tmpl->name, name)) continue; //table not found try_module_get list_for_each_entry(t, &xt_net->tables[af]...) return t; //not get refcnt module_put(t->me) //uaf unregister_pernet_subsys //remove table from xt_net list While xt_table module was going away and has been removed from xt_templates list, we couldnt get refcnt of xt_table->me. Check module in xt_net->tables list re-traversal to fix it. Fixes: fdacd57c79b7 ("netfilter: x_tables: never register tables by default") Signed-off-by: Dong Chenchen Reviewed-by: Florian Westphal --- net/netfilter/x_tables.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/net/netfilter/x_tables.c b/net/netfilter/x_tables.c index da5d929c7c85..709840612f0d 100644 --- a/net/netfilter/x_tables.c +++ b/net/netfilter/x_tables.c @@ -1269,7 +1269,7 @@ struct xt_table *xt_find_table_lock(struct net *net, u_int8_t af, /* and once again: */ list_for_each_entry(t, &xt_net->tables[af], list) - if (strcmp(t->name, name) == 0) + if (strcmp(t->name, name) == 0 && owner == t->me) return t; module_put(owner);