Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932754Ab1DZV2i (ORCPT ); Tue, 26 Apr 2011 17:28:38 -0400 Received: from mga01.intel.com ([192.55.52.88]:1206 "EHLO mga01.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932306Ab1DZVOb (ORCPT ); Tue, 26 Apr 2011 17:14:31 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="4.64,270,1301900400"; d="scan'208";a="914748566" From: Andi Kleen References: <20110426212.641772347@firstfloor.org> In-Reply-To: <20110426212.641772347@firstfloor.org> To: torvalds@linux-foundation.org, andy.grover@oracle.com, davem@davemloft.net, ak@linux.intel.com, stefan.bader@canonical.com, tim.gardner@canonical.com, brad.figg@canonical.com, gregkh@suse.de, linux-kernel@vger.kernel.org, stable@kernel.org, tim.bird@am.sony.com Subject: [PATCH] [51/106] net: fix rds_iovec page count overflow Message-Id: <20110426211331.684743E1886@tassilo.jf.intel.com> Date: Tue, 26 Apr 2011 14:13:31 -0700 (PDT) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2233 Lines: 61 2.6.35-longterm review patch. If anyone has any objections, please let me know. ------------------ From: Linus Torvalds 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. Reported-by: Thomas Pollet Signed-off-by: Linus Torvalds Signed-off-by: Andy Grover Signed-off-by: David S. Miller Signed-off-by: Andi Kleen [v2: nr is unsigned in the old code] Signed-off-by: Stefan Bader Acked-by: Tim Gardner Acked-by: Brad Figg Signed-off-by: Greg Kroah-Hartman --- net/rds/rdma.c | 11 +++++++++++ 1 file changed, 11 insertions(+) Index: linux-2.6.35.y/net/rds/rdma.c =================================================================== --- linux-2.6.35.y.orig/net/rds/rdma.c +++ linux-2.6.35.y/net/rds/rdma.c @@ -500,6 +500,17 @@ static struct rds_rdma_op *rds_rdma_prep max_pages = max(nr, max_pages); nr_pages += nr; + + /* + * nr for one entry in limited to (UINT_MAX>>PAGE_SHIFT)+1 + * so nr_pages cannot overflow without becoming bigger than + * INT_MAX first. If nr cannot overflow then max_pages should + * be ok. + */ + if (nr_pages > INT_MAX) { + ret = -EINVAL; + goto out; + } } pages = kcalloc(max_pages, sizeof(struct page *), GFP_KERNEL); -- 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/