From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932774AbbLXPnV (ORCPT ); Thu, 24 Dec 2015 10:43:21 -0500 Received: from shadbolt.e.decadent.org.uk ([88.96.1.126]:51463 "EHLO shadbolt.e.decadent.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753816AbbLXPmd (ORCPT ); Thu, 24 Dec 2015 10:42:33 -0500 Content-Type: text/plain; charset="UTF-8" Content-Disposition: inline Content-Transfer-Encoding: 8bit MIME-Version: 1.0 From: Ben Hutchings To: linux-kernel@vger.kernel.org, stable@vger.kernel.org CC: akpm@linux-foundation.org, "Hannes Frederic Sowa" , "Cong Wang" , "David S. Miller" , "=?UTF-8?Q?=E9=83=AD=E6=B0=B8=E5=88=9A?=" Date: Thu, 24 Dec 2015 15:37:42 +0000 Message-ID: X-Mailer: LinuxStableQueue (scripts by bwh) Subject: [PATCH 3.2 70/77] net: add validation for the socket syscall protocol argument In-Reply-To: X-SA-Exim-Connect-IP: 192.168.4.247 X-SA-Exim-Mail-From: ben@decadent.org.uk X-SA-Exim-Scanned: No (on shadbolt.decadent.org.uk); SAEximRunCond expanded to false Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.2.75-rc1 review patch. If anyone has any objections, please let me know. ------------------ From: Hannes Frederic Sowa [ Upstream commit 79462ad02e861803b3840cc782248c7359451cd9 ] 郭永刚 reported that one could simply crash the kernel as root by using a simple program: int socket_fd; struct sockaddr_in addr; addr.sin_port = 0; addr.sin_addr.s_addr = INADDR_ANY; addr.sin_family = 10; socket_fd = socket(10,3,0x40000000); connect(socket_fd , &addr,16); AF_INET, AF_INET6 sockets actually only support 8-bit protocol identifiers. inet_sock's skc_protocol field thus is sized accordingly, thus larger protocol identifiers simply cut off the higher bits and store a zero in the protocol fields. This could lead to e.g. NULL function pointer because as a result of the cut off inet_num is zero and we call down to inet_autobind, which is NULL for raw sockets. kernel: Call Trace: kernel: [] ? inet_autobind+0x2e/0x70 kernel: [] inet_dgram_connect+0x54/0x80 kernel: [] SYSC_connect+0xd9/0x110 kernel: [] ? ptrace_notify+0x5b/0x80 kernel: [] ? syscall_trace_enter_phase2+0x108/0x200 kernel: [] SyS_connect+0xe/0x10 kernel: [] tracesys_phase2+0x84/0x89 I found no particular commit which introduced this problem. CVE: CVE-2015-8543 Cc: Cong Wang Reported-by: 郭永刚 Signed-off-by: Hannes Frederic Sowa Signed-off-by: David S. Miller [bwh: Backported to 3.2: open-code U8_MAX] Signed-off-by: Ben Hutchings --- include/net/sock.h | 1 + net/ax25/af_ax25.c | 3 +++ net/decnet/af_decnet.c | 3 +++ net/ipv4/af_inet.c | 3 +++ net/ipv6/af_inet6.c | 3 +++ net/irda/af_irda.c | 3 +++ 6 files changed, 16 insertions(+) --- a/include/net/sock.h +++ b/include/net/sock.h @@ -302,6 +302,7 @@ struct sock { sk_no_check : 2, sk_userlocks : 4, sk_protocol : 8, +#define SK_PROTOCOL_MAX ((u8)~0U) sk_type : 16; kmemcheck_bitfield_end(flags); int sk_wmem_queued; --- a/net/ax25/af_ax25.c +++ b/net/ax25/af_ax25.c @@ -806,6 +806,9 @@ static int ax25_create(struct net *net, struct sock *sk; ax25_cb *ax25; + if (protocol < 0 || protocol > SK_PROTOCOL_MAX) + return -EINVAL; + if (!net_eq(net, &init_net)) return -EAFNOSUPPORT; --- a/net/decnet/af_decnet.c +++ b/net/decnet/af_decnet.c @@ -681,6 +681,9 @@ static int dn_create(struct net *net, st { struct sock *sk; + if (protocol < 0 || protocol > SK_PROTOCOL_MAX) + return -EINVAL; + if (!net_eq(net, &init_net)) return -EAFNOSUPPORT; --- a/net/ipv4/af_inet.c +++ b/net/ipv4/af_inet.c @@ -279,6 +279,9 @@ static int inet_create(struct net *net, int try_loading_module = 0; int err; + if (protocol < 0 || protocol >= IPPROTO_MAX) + return -EINVAL; + if (unlikely(!inet_ehash_secret)) if (sock->type != SOCK_RAW && sock->type != SOCK_DGRAM) build_ehash_secret(); --- a/net/ipv6/af_inet6.c +++ b/net/ipv6/af_inet6.c @@ -109,6 +109,9 @@ static int inet6_create(struct net *net, int try_loading_module = 0; int err; + if (protocol < 0 || protocol >= IPPROTO_MAX) + return -EINVAL; + if (sock->type != SOCK_RAW && sock->type != SOCK_DGRAM && !inet_ehash_secret) --- a/net/irda/af_irda.c +++ b/net/irda/af_irda.c @@ -1106,6 +1106,9 @@ static int irda_create(struct net *net, IRDA_DEBUG(2, "%s()\n", __func__); + if (protocol < 0 || protocol > SK_PROTOCOL_MAX) + return -EINVAL; + if (net != &init_net) return -EAFNOSUPPORT;