Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933871Ab1FWRiv (ORCPT ); Thu, 23 Jun 2011 13:38:51 -0400 Received: from mail.windriver.com ([147.11.1.11]:35648 "EHLO mail.windriver.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933847Ab1FWRin (ORCPT ); Thu, 23 Jun 2011 13:38:43 -0400 From: Paul Gortmaker To: stable@kernel.org, linux-kernel@vger.kernel.org Cc: stable-review@kernel.org, Dan Rosenberg , "David S. Miller" , Paul Gortmaker Subject: [34-longterm 236/247] irda: prevent integer underflow in IRLMP_ENUMDEVICES Date: Thu, 23 Jun 2011 13:35:04 -0400 Message-Id: <1308850515-15242-177-git-send-email-paul.gortmaker@windriver.com> X-Mailer: git-send-email 1.7.4.4 In-Reply-To: <1308850515-15242-1-git-send-email-paul.gortmaker@windriver.com> References: <1308849690-14530-1-git-send-email-paul.gortmaker@windriver.com> <1308850515-15242-1-git-send-email-paul.gortmaker@windriver.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2329 Lines: 66 From: Dan Rosenberg ------------------- This is a commit scheduled for the next v2.6.34 longterm release. If you see a problem with using this for longterm, please comment. ------------------- 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 Signed-off-by: Paul Gortmaker --- net/irda/af_irda.c | 16 +++++++++------- 1 files changed, 9 insertions(+), 7 deletions(-) diff --git a/net/irda/af_irda.c b/net/irda/af_irda.c index 6fae047..e63c226 100644 --- a/net/irda/af_irda.c +++ b/net/irda/af_irda.c @@ -2278,6 +2278,14 @@ 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) + return -EINVAL; + /* Ask lmp for the current discovery log */ discoveries = irlmp_get_discoveries(&list.len, self->mask.word, self->nslots); @@ -2287,15 +2295,9 @@ static int __irda_getsockopt(struct socket *sock, int level, int optname, 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) { -- 1.7.4.4 -- 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/