Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753753Ab3EKQcK (ORCPT ); Sat, 11 May 2013 12:32:10 -0400 Received: from userp1040.oracle.com ([156.151.31.81]:29209 "EHLO userp1040.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753620Ab3EKQcI (ORCPT ); Sat, 11 May 2013 12:32:08 -0400 Date: Sat, 11 May 2013 19:31:55 +0300 From: Dan Carpenter To: Matthew Wilcox Cc: Keith Busch , Vishal Verma , linux-kernel@vger.kernel.org, kernel-janitors@vger.kernel.org Subject: [patch] NVMe: check for integer overflow in nvme_map_user_pages() Message-ID: <20130511163155.GA21427@elgon.mountain> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline User-Agent: Mutt/1.5.21 (2010-09-15) X-Source-IP: ucsinet22.oracle.com [156.151.31.94] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1548 Lines: 40 You need to have CAP_SYS_ADMIN to trigger this overflow but it makes the static checkers complain so we should fix it. The worry is that "length" comes from copy_from_user() so we need to check that "length + offset" can't overflow. I also changed the min_t() cast to be unsigned instead of signed. Now that we cap "length" to INT_MAX it doesn't make a difference, but it's a little easier for reviewers to know that large values aren't cast to negative. Signed-off-by: Dan Carpenter diff --git a/drivers/block/nvme-core.c b/drivers/block/nvme-core.c index 8efdfaa..4376375 100644 --- a/drivers/block/nvme-core.c +++ b/drivers/block/nvme-core.c @@ -1206,7 +1206,7 @@ struct nvme_iod *nvme_map_user_pages(struct nvme_dev *dev, int write, if (addr & 3) return ERR_PTR(-EINVAL); - if (!length) + if (!length || length > INT_MAX - PAGE_SIZE) return ERR_PTR(-EINVAL); offset = offset_in_page(addr); @@ -1227,7 +1227,8 @@ struct nvme_iod *nvme_map_user_pages(struct nvme_dev *dev, int write, sg_init_table(sg, count); for (i = 0; i < count; i++) { sg_set_page(&sg[i], pages[i], - min_t(int, length, PAGE_SIZE - offset), offset); + min_t(unsigned, length, PAGE_SIZE - offset), + offset); length -= (PAGE_SIZE - offset); offset = 0; } -- 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/