Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755867AbbLQBFP (ORCPT ); Wed, 16 Dec 2015 20:05:15 -0500 Received: from aserp1040.oracle.com ([141.146.126.69]:50451 "EHLO aserp1040.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755816AbbLQBFK (ORCPT ); Wed, 16 Dec 2015 20:05:10 -0500 Subject: Re: [PATCH] inet: sanitize socket() protocol value To: Eric Dumazet References: <1450313821-27217-1-git-send-email-vegard.nossum@oracle.com> Cc: "David S. Miller" , netdev , LKML From: Vegard Nossum Message-ID: <56720A3D.9030002@oracle.com> Date: Thu, 17 Dec 2015 02:05:01 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:38.0) Gecko/20100101 Thunderbird/38.2.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit X-Source-IP: userv0022.oracle.com [156.151.31.74] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3672 Lines: 86 On 12/17/2015 02:01 AM, Eric Dumazet wrote: > On Wed, Dec 16, 2015 at 4:57 PM, Vegard Nossum wrote: >> If you create a raw socket with a protocol of e.g. 0x10000, then >> inet_sk(sk)->inet_num will get set to 0 since it only has room for 16 >> bits. This causes problems further down the line as lots of code makes >> assumptions about ->inet_num, for example connect()...inet_autobind() >> will attempt to call sk->sk_prot->get_port() which is invalid: >> >> BUG: unable to handle kernel NULL pointer dereference at (null) >> IP: [< (null)>] (null) >> PGD 19ea0067 PUD 19d3f067 PMD 0 >> Oops: 0010 [#1] SMP >> CPU: 1 PID: 849 Comm: a.out Not tainted 4.4.0-rc4+ #287 >> task: ffff880019a12640 ti: ffff88000008c000 task.ti: ffff88000008c000 >> RIP: 0010:[<0000000000000000>] [< (null)>] (null) >> RSP: 0018:ffff88000008fe50 EFLAGS: 00010246 >> RAX: ffffffff81cc61f0 RBX: ffff880019d2ca80 RCX: 0000000000000802 >> RDX: 0000000000000001 RSI: 0000000000000000 RDI: ffff880019d2ca80 >> RBP: ffff88000008fe60 R08: 00007f0e6b132e80 R09: ffff880019d2ca80 >> R10: ffff88001a7a72e0 R11: ffff880019a12640 R12: 000000000000000b >> R13: 0000000000400644 R14: 0000000000000000 R15: 0000000000000000 >> FS: 00007f0e6b355740(0000) GS:ffff88001a900000(0000) knlGS:0000000000000000 >> CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 >> CR2: 0000000000000000 CR3: 0000000019d3d000 CR4: 00000000001406a0 >> Stack: >> ffffffff815f1c69 ffff880019d2ca80 ffff88000008fe88 ffffffff815f1cde >> 0000000b0000000b ffff88000008fea0 ffff880019484000 ffff88000008ff38 >> ffffffff8156f310 0000000000000000 2a2a2a2a2a2a2a2a ffffffff8100002a >> Call Trace: >> [] ? inet_autobind+0x23/0x50 >> [] inet_dgram_connect+0x48/0x64 >> [] SYSC_connect+0x84/0xae >> [] ? sock_alloc_file+0xb3/0x108 >> [] ? fd_install+0x20/0x22 >> [] ? SYSC_socket+0x62/0x90 >> [] SyS_connect+0x9/0xb >> [] entry_SYSCALL_64_fastpath+0x12/0x71 >> Code: Bad RIP value. >> RIP [< (null)>] (null) >> RSP >> CR2: 0000000000000000 >> ---[ end trace bd60b4fe2edc2537 ]--- >> >> Signed-off-by: Vegard Nossum >> Cc: Eric Dumazet >> Cc: >> --- >> net/ipv4/af_inet.c | 6 ++++++ >> 1 file changed, 6 insertions(+) >> >> diff --git net/ipv4/af_inet.c net/ipv4/af_inet.c >> index 11c4ca1..4e1583a 100644 >> --- net/ipv4/af_inet.c >> +++ net/ipv4/af_inet.c >> @@ -316,6 +316,12 @@ lookup_protocol: >> >> WARN_ON(!answer_prot->slab); >> >> + /* Check that the protocol we were given will actually fit in >> + * inet->inet_num. */ >> + err = -EINVAL; >> + if (protocol != (typeof(inet->inet_num)) protocol) >> + goto out; >> + >> err = -ENOBUFS; >> sk = sk_alloc(net, PF_INET, GFP_KERNEL, answer_prot, kern); >> if (!sk) >> -- >> 1.9.1 >> > > It looks already fixed in a better way (IPv6, ...) > > http://git.kernel.org/cgit/linux/kernel/git/davem/net.git/commit/?id=79462ad02e861803b3840cc782248c7359451cd9 Ha, sorry, I missed that! Thanks for the quick response. Vegard -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/