Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933937Ab1FWRly (ORCPT ); Thu, 23 Jun 2011 13:41:54 -0400 Received: from mail.windriver.com ([147.11.1.11]:35793 "EHLO mail.windriver.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933869Ab1FWRjC (ORCPT ); Thu, 23 Jun 2011 13:39:02 -0400 From: Paul Gortmaker To: stable@kernel.org, linux-kernel@vger.kernel.org Cc: stable-review@kernel.org, Linus Torvalds , Andy Grover , "David S. Miller" , Paul Gortmaker Subject: [34-longterm 246/247] net: fix rds_iovec page count overflow Date: Thu, 23 Jun 2011 13:35:14 -0400 Message-Id: <1308850515-15242-187-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: 2175 Lines: 61 From: Linus Torvalds ------------------- 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 1b1f693d7ad6d193862dcb1118540a030c5e761f upstream. As reported by Thomas Pollet, the rdma page counting can overflow. We get the rdma sizes in 64-bit unsigned entities, but then limit it to UINT_MAX bytes and shift them down to pages (so with a possible "+1" for an unaligned address). So each individual page count fits comfortably in an 'unsigned int' (not even close to overflowing into signed), but as they are added up, they might end up resulting in a signed return value. Which would be wrong. Catch the case of tot_pages turning negative, and return the appropriate error code. [PG: In 34, var names are slightly different, 1b1f6's tot_pages is 34's nr_pages, and 1b1f6's nr_pages is 34's nr; so map accordingly.] Reported-by: Thomas Pollet Signed-off-by: Linus Torvalds Signed-off-by: Andy Grover Signed-off-by: David S. Miller Signed-off-by: Paul Gortmaker --- net/rds/rdma.c | 9 +++++++++ 1 files changed, 9 insertions(+), 0 deletions(-) diff --git a/net/rds/rdma.c b/net/rds/rdma.c index cf0dfa7..3481931 100644 --- a/net/rds/rdma.c +++ b/net/rds/rdma.c @@ -498,6 +498,15 @@ static struct rds_rdma_op *rds_rdma_prepare(struct rds_sock *rs, max_pages = max(nr, max_pages); nr_pages += nr; + + /* + * nr for one entry is limited to (UINT_MAX>>PAGE_SHIFT)+1, + * so nr_pages cannot overflow without first going negative. + */ + if ((int)nr_pages < 0) { + ret = -EINVAL; + goto out; + } } pages = kcalloc(max_pages, sizeof(struct page *), GFP_KERNEL); -- 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/