From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932483Ab1DYUZc (ORCPT ); Mon, 25 Apr 2011 16:25:32 -0400 Received: from 1wt.eu ([62.212.114.60]:34518 "EHLO 1wt.eu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932342Ab1DYUZP (ORCPT ); Mon, 25 Apr 2011 16:25:15 -0400 Message-Id: <20110425200239.815172404@pcw.home.local> User-Agent: quilt/0.48-1 Date: Mon, 25 Apr 2011 22:05:09 +0200 From: Willy Tarreau To: linux-kernel@vger.kernel.org, stable@kernel.org, stable-review@kernel.org Cc: Dan Rosenberg , "David S. Miller" , Moritz Muehlenhoff , Greg Kroah-Hartman Subject: [PATCH 157/173] irda: prevent integer underflow in IRLMP_ENUMDEVICES In-Reply-To: <46075c3a3ef08be6d70339617d6afc98@local> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 2.6.27.59-stable review patch. If anyone has any objections, please let us know. ------------------ From: Dan Rosenberg commit fdac1e0697356ac212259f2147aa60c72e334861 upstream. 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 Signed-off-by: David S. Miller Cc: Moritz Muehlenhoff Signed-off-by: Greg Kroah-Hartman --- net/irda/af_irda.c | 16 +++++++++------- 1 file changed, 9 insertions(+), 7 deletions(-) --- a/net/irda/af_irda.c +++ b/net/irda/af_irda.c @@ -2164,6 +2164,14 @@ static int irda_getsockopt(struct socket switch (optname) { case IRLMP_ENUMDEVICES: + + /* Offset to first device entry */ + offset = sizeof(struct irda_device_list) - + sizeof(struct irda_device_info); + + if (len < offset) + return -EINVAL; + /* Ask lmp for the current discovery log */ discoveries = irlmp_get_discoveries(&list.len, self->mask.word, self->nslots); @@ -2173,15 +2181,9 @@ static int irda_getsockopt(struct socket err = 0; /* 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) {