From patchwork Thu Jul 25 19:28:20 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Kuniyuki Iwashima X-Patchwork-Id: 13742098 X-Patchwork-Delegate: kuba@kernel.org Received: from smtp-fw-52003.amazon.com (smtp-fw-52003.amazon.com [52.119.213.152]) (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 EE741364A4; Thu, 25 Jul 2024 19:29:03 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=52.119.213.152 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1721935745; cv=none; b=VTfJGxkku70pGCYfyKKr4a97EAql8NqvTm0UGNigg2eCU4twRS/8xHSPJZQLkLQZxmJdJ+RJP6lzzop89mX1Ct+dI0pJ3r6uYlrlC07rokw83UOAZ7YO89ykrHhcIKoXMxkpSed93ErnigWkVNThRzVhHkVuAz9NFnfWpk5tZ+A= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1721935745; c=relaxed/simple; bh=Q/znnOJhdo0wsH6GA8DmbIibs4se7mo44cJMi4y7YvE=; h=From:To:CC:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=LzEjE+4Mz1dOkX3WW/VU1npGVzOY3QOpaD+AeFodt4o8c8Yie4qo0d5JINjkeNfpCKPCrWX9qlOM1wXcqY4tdEx+rMVr9Q6zDiL0K3n+qWTtXlpe2B4oruYXNPCi0ew+gS//HwvBA1IB6iR8VZa9O/ExUrvlrdvmTT4CJJnhCNs= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=amazon.com; spf=pass smtp.mailfrom=amazon.co.jp; dkim=pass (1024-bit key) header.d=amazon.com header.i=@amazon.com header.b=enZzmWV/; arc=none smtp.client-ip=52.119.213.152 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=amazon.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=amazon.co.jp Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=amazon.com header.i=@amazon.com header.b="enZzmWV/" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=amazon.com; i=@amazon.com; q=dns/txt; s=amazon201209; t=1721935745; x=1753471745; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=0OpIpcRPTGgj6LUxUrMr4YJlXHwdHkGgf0VGsfHvBro=; b=enZzmWV/UglT299FOUy9VBWREQ1OXPka4CunJi2gXW+XXmTgtRm1YG0I yu0z1McktDbsXeaRpPssPOax76K6roFZmPQZ4gT4ucSYJjI7eRtEXCoDy goOBZPtOuBwmA3/mIAJr68w/S0CIfxu58QkJcq0f46J2nurw0os2EMvPY o=; X-IronPort-AV: E=Sophos;i="6.09,236,1716249600"; d="scan'208";a="15012923" Received: from iad12-co-svc-p1-lb1-vlan3.amazon.com (HELO smtpout.prod.us-west-2.prod.farcaster.email.amazon.dev) ([10.43.8.6]) by smtp-border-fw-52003.iad7.amazon.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 25 Jul 2024 19:29:02 +0000 Received: from EX19MTAUWA002.ant.amazon.com [10.0.21.151:32421] by smtpin.naws.us-west-2.prod.farcaster.email.amazon.dev [10.0.8.122:2525] with esmtp (Farcaster) id 5a9f12ee-c6b0-47ff-ba02-5fd4d076505e; Thu, 25 Jul 2024 19:29:00 +0000 (UTC) X-Farcaster-Flow-ID: 5a9f12ee-c6b0-47ff-ba02-5fd4d076505e Received: from EX19D004ANA001.ant.amazon.com (10.37.240.138) by EX19MTAUWA002.ant.amazon.com (10.250.64.202) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA) id 15.2.1258.34; Thu, 25 Jul 2024 19:29:00 +0000 Received: from 88665a182662.ant.amazon.com (10.88.167.203) by EX19D004ANA001.ant.amazon.com (10.37.240.138) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA) id 15.2.1258.34; Thu, 25 Jul 2024 19:28:57 +0000 From: Kuniyuki Iwashima To: Pablo Neira Ayuso , Jozsef Kadlecsik CC: Florian Westphal , Kuniyuki Iwashima , Kuniyuki Iwashima , , , , Takahiro Kawahara Subject: [PATCH v1 nf 1/2] netfilter: iptables: Fix null-ptr-deref in iptable_nat_table_init(). Date: Thu, 25 Jul 2024 12:28:20 -0700 Message-ID: <20240725192822.4478-2-kuniyu@amazon.com> X-Mailer: git-send-email 2.30.2 In-Reply-To: <20240725192822.4478-1-kuniyu@amazon.com> References: <20240725192822.4478-1-kuniyu@amazon.com> Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-ClientProxiedBy: EX19D041UWA003.ant.amazon.com (10.13.139.105) To EX19D004ANA001.ant.amazon.com (10.37.240.138) X-Patchwork-Delegate: kuba@kernel.org We had a report that iptables-restore sometimes triggered null-ptr-deref at boot time. [0] The problem is that iptable_nat_table_init() is exposed to user space before the kernel fully initialises netns. In the small race window, a user could call iptable_nat_table_init() that accesses net_generic(net, iptable_nat_net_id), which is available only after registering iptable_nat_net_ops. Let's call register_pernet_subsys() before xt_register_template(). [0]: bpfilter: Loaded bpfilter_umh pid 11702 Started bpfilter BUG: kernel NULL pointer dereference, address: 0000000000000013 PF: supervisor write access in kernel mode PF: error_code(0x0002) - not-present page PGD 0 P4D 0 PREEMPT SMP NOPTI CPU: 2 PID: 11879 Comm: iptables-restor Not tainted 6.1.92-99.174.amzn2023.x86_64 #1 Hardware name: Amazon EC2 c6i.4xlarge/, BIOS 1.0 10/16/2017 RIP: 0010:iptable_nat_table_init (net/ipv4/netfilter/iptable_nat.c:87 net/ipv4/netfilter/iptable_nat.c:121) iptable_nat Code: 10 4c 89 f6 48 89 ef e8 0b 19 bb ff 41 89 c4 85 c0 75 38 41 83 c7 01 49 83 c6 28 41 83 ff 04 75 dc 48 8b 44 24 08 48 8b 0c 24 <48> 89 08 4c 89 ef e8 a2 3b a2 cf 48 83 c4 10 44 89 e0 5b 5d 41 5c RSP: 0018:ffffbef902843cd0 EFLAGS: 00010246 RAX: 0000000000000013 RBX: ffff9f4b052caa20 RCX: ffff9f4b20988d80 RDX: 0000000000000000 RSI: 0000000000000064 RDI: ffffffffc04201c0 RBP: ffff9f4b29394000 R08: ffff9f4b07f77258 R09: ffff9f4b07f77240 R10: 0000000000000000 R11: ffff9f4b09635388 R12: 0000000000000000 R13: ffff9f4b1a3c6c00 R14: ffff9f4b20988e20 R15: 0000000000000004 FS: 00007f6284340000(0000) GS:ffff9f51fe280000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000000000013 CR3: 00000001d10a6005 CR4: 00000000007706e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 PKRU: 55555554 Call Trace: ? show_trace_log_lvl (arch/x86/kernel/dumpstack.c:259) ? show_trace_log_lvl (arch/x86/kernel/dumpstack.c:259) ? xt_find_table_lock (net/netfilter/x_tables.c:1259) ? __die_body.cold (arch/x86/kernel/dumpstack.c:478 arch/x86/kernel/dumpstack.c:420) ? page_fault_oops (arch/x86/mm/fault.c:727) ? exc_page_fault (./arch/x86/include/asm/irqflags.h:40 ./arch/x86/include/asm/irqflags.h:75 arch/x86/mm/fault.c:1470 arch/x86/mm/fault.c:1518) ? asm_exc_page_fault (./arch/x86/include/asm/idtentry.h:570) ? iptable_nat_table_init (net/ipv4/netfilter/iptable_nat.c:87 net/ipv4/netfilter/iptable_nat.c:121) iptable_nat xt_find_table_lock (net/netfilter/x_tables.c:1259) xt_request_find_table_lock (net/netfilter/x_tables.c:1287) get_info (net/ipv4/netfilter/ip_tables.c:965) ? security_capable (security/security.c:809 (discriminator 13)) ? ns_capable (kernel/capability.c:376 kernel/capability.c:397) ? do_ipt_get_ctl (net/ipv4/netfilter/ip_tables.c:1656) ? bpfilter_send_req (net/bpfilter/bpfilter_kern.c:52) bpfilter nf_getsockopt (net/netfilter/nf_sockopt.c:116) ip_getsockopt (net/ipv4/ip_sockglue.c:1827) __sys_getsockopt (net/socket.c:2327) __x64_sys_getsockopt (net/socket.c:2342 net/socket.c:2339 net/socket.c:2339) do_syscall_64 (arch/x86/entry/common.c:51 arch/x86/entry/common.c:81) entry_SYSCALL_64_after_hwframe (arch/x86/entry/entry_64.S:121) RIP: 0033:0x7f62844685ee Code: 48 8b 0d 45 28 0f 00 f7 d8 64 89 01 48 83 c8 ff c3 66 2e 0f 1f 84 00 00 00 00 00 90 f3 0f 1e fa 49 89 ca b8 37 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 0a c3 66 0f 1f 84 00 00 00 00 00 48 8b 15 09 RSP: 002b:00007ffd1f83d638 EFLAGS: 00000246 ORIG_RAX: 0000000000000037 RAX: ffffffffffffffda RBX: 00007ffd1f83d680 RCX: 00007f62844685ee RDX: 0000000000000040 RSI: 0000000000000000 RDI: 0000000000000004 RBP: 0000000000000004 R08: 00007ffd1f83d670 R09: 0000558798ffa2a0 R10: 00007ffd1f83d680 R11: 0000000000000246 R12: 00007ffd1f83e3b2 R13: 00007f628455baa0 R14: 00007ffd1f83d7b0 R15: 00007f628457a008 Modules linked in: iptable_nat(+) bpfilter rpcsec_gss_krb5 auth_rpcgss nfsv4 dns_resolver nfs lockd grace fscache veth xt_state xt_connmark xt_nat xt_statistic xt_MASQUERADE xt_mark xt_addrtype ipt_REJECT nf_reject_ipv4 nft_chain_nat nf_nat xt_conntrack nf_conntrack nf_defrag_ipv6 nf_defrag_ipv4 xt_comment nft_compat nf_tables nfnetlink overlay nls_ascii nls_cp437 vfat fat ghash_clmulni_intel aesni_intel ena crypto_simd ptp cryptd i8042 pps_core serio button sunrpc sch_fq_codel configfs loop dm_mod fuse dax dmi_sysfs crc32_pclmul crc32c_intel efivarfs CR2: 0000000000000013 Fixes: fdacd57c79b7 ("netfilter: x_tables: never register tables by default") Reported-by: Takahiro Kawahara Signed-off-by: Kuniyuki Iwashima --- net/ipv4/netfilter/iptable_nat.c | 18 ++++++++++-------- 1 file changed, 10 insertions(+), 8 deletions(-) diff --git a/net/ipv4/netfilter/iptable_nat.c b/net/ipv4/netfilter/iptable_nat.c index 4d42d0756fd7..a5db7c67d61b 100644 --- a/net/ipv4/netfilter/iptable_nat.c +++ b/net/ipv4/netfilter/iptable_nat.c @@ -145,25 +145,27 @@ static struct pernet_operations iptable_nat_net_ops = { static int __init iptable_nat_init(void) { - int ret = xt_register_template(&nf_nat_ipv4_table, - iptable_nat_table_init); + int ret; + /* net->gen->ptr[iptable_nat_net_id] must be allocated + * before calling iptable_nat_table_init(). + */ + ret = register_pernet_subsys(&iptable_nat_net_ops); if (ret < 0) return ret; - ret = register_pernet_subsys(&iptable_nat_net_ops); - if (ret < 0) { - xt_unregister_template(&nf_nat_ipv4_table); - return ret; - } + ret = xt_register_template(&nf_nat_ipv4_table, + iptable_nat_table_init); + if (ret < 0) + unregister_pernet_subsys(&iptable_nat_net_ops); return ret; } static void __exit iptable_nat_exit(void) { - unregister_pernet_subsys(&iptable_nat_net_ops); xt_unregister_template(&nf_nat_ipv4_table); + unregister_pernet_subsys(&iptable_nat_net_ops); } module_init(iptable_nat_init);