From patchwork Wed Dec 22 23:58:27 2010 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Dan Rosenberg X-Patchwork-Id: 76460 X-Patchwork-Delegate: davem@davemloft.net Return-Path: X-Original-To: patchwork-incoming@ozlabs.org Delivered-To: patchwork-incoming@ozlabs.org Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by ozlabs.org (Postfix) with ESMTP id 6271DB70D6 for ; Thu, 23 Dec 2010 10:58:36 +1100 (EST) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752988Ab0LVX6c (ORCPT ); Wed, 22 Dec 2010 18:58:32 -0500 Received: from mx1.vsecurity.com ([209.67.252.12]:51215 "EHLO mx1.vsecurity.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752974Ab0LVX6b (ORCPT ); Wed, 22 Dec 2010 18:58:31 -0500 Received: (qmail 58703 invoked from network); 22 Dec 2010 23:58:28 -0000 Received: from ool-4356063f.dyn.optonline.net (HELO [192.168.1.116]) (drosenbe@[67.86.6.63]) (envelope-sender ) by mx1.vsecurity.com (qmail-ldap-1.03) with SMTP for ; 22 Dec 2010 23:58:28 -0000 Subject: [PATCH] irda: prevent integer underflow in IRLMP_ENUMDEVICES From: Dan Rosenberg To: samuel@sortiz.org, davem@davemloft.net Cc: netdev@vger.kernel.org, security@kernel.org Date: Wed, 22 Dec 2010 18:58:27 -0500 Message-ID: <1293062307.9820.331.camel@dan> Mime-Version: 1.0 X-Mailer: Evolution 2.28.3 Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org If the user-provided len is less than the expected offset, the IRLMP_ENUMDEVICES getsockopt will do a copy_to_user() with a very large size value. While this isn't be a security issue on x86 because it will get caught by the access_ok() check, it may leak large amounts of kernel heap on other architectures. In any event, this patch fixes it. Signed-off-by: Dan Rosenberg Cc: stable --- net/irda/af_irda.c | 18 +++++++++++------- 1 files changed, 11 insertions(+), 7 deletions(-) -- To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html diff --git a/net/irda/af_irda.c b/net/irda/af_irda.c index a6de305..241d7a0 100644 --- a/net/irda/af_irda.c +++ b/net/irda/af_irda.c @@ -2280,6 +2280,16 @@ static int irda_getsockopt(struct socket *sock, int level, int optname, switch (optname) { case IRLMP_ENUMDEVICES: + + /* Offset to first device entry */ + offset = sizeof(struct irda_device_list) - + sizeof(struct irda_device_info); + + if (len < offset) { + err = -EINVAL; + goto out; + } + /* Ask lmp for the current discovery log */ discoveries = irlmp_get_discoveries(&list.len, self->mask.word, self->nslots); @@ -2290,15 +2300,9 @@ static int irda_getsockopt(struct socket *sock, int level, int optname, } /* Write total list length back to client */ - if (copy_to_user(optval, &list, - sizeof(struct irda_device_list) - - sizeof(struct irda_device_info))) + if (copy_to_user(optval, &list, offset)) err = -EFAULT; - /* Offset to first device entry */ - offset = sizeof(struct irda_device_list) - - sizeof(struct irda_device_info); - /* Copy the list itself - watch for overflow */ if (list.len > 2048) { err = -EINVAL;