From patchwork Thu Apr 18 09:16:51 2013 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Luis Henriques X-Patchwork-Id: 237564 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Received: from casper.infradead.org (casper.infradead.org [IPv6:2001:770:15f::2]) (using TLSv1.2 with cipher DHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (Client did not present a certificate) by ozlabs.org (Postfix) with ESMTPS id 551142C00A7 for ; Thu, 18 Apr 2013 19:18:55 +1000 (EST) Received: from merlin.infradead.org ([2001:4978:20e::2]) by casper.infradead.org with esmtps (Exim 4.80.1 #2 (Red Hat Linux)) id 1USkzE-00007E-Fr; Thu, 18 Apr 2013 09:18:36 +0000 Received: from localhost ([::1] helo=merlin.infradead.org) by merlin.infradead.org with esmtp (Exim 4.80.1 #2 (Red Hat Linux)) id 1USkzC-00084t-K9; Thu, 18 Apr 2013 09:18:34 +0000 Received: from youngberry.canonical.com ([91.189.89.112]) by merlin.infradead.org with esmtp (Exim 4.80.1 #2 (Red Hat Linux)) id 1USkzA-00084J-Hn for linux-mtd@lists.infradead.org; Thu, 18 Apr 2013 09:18:33 +0000 Received: from bl20-140-10.dsl.telepac.pt ([2.81.140.10] helo=localhost) by youngberry.canonical.com with esmtpsa (TLS1.0:DHE_RSA_AES_128_CBC_SHA1:16) (Exim 4.71) (envelope-from ) id 1USkz9-0002Gi-KP; Thu, 18 Apr 2013 09:18:32 +0000 From: Luis Henriques To: linux-kernel@vger.kernel.org, stable@vger.kernel.org, kernel-team@lists.ubuntu.com Subject: [PATCH 66/72] mtdchar: fix offset overflow detection Date: Thu, 18 Apr 2013 10:16:51 +0100 Message-Id: <1366276617-3553-67-git-send-email-luis.henriques@canonical.com> X-Mailer: git-send-email 1.8.1.2 In-Reply-To: <1366276617-3553-1-git-send-email-luis.henriques@canonical.com> References: <1366276617-3553-1-git-send-email-luis.henriques@canonical.com> X-Extended-Stable: 3.5 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20130418_051832_701016_8BF47E4D X-CRM114-Status: GOOD ( 20.18 ) X-Spam-Score: -3.3 (---) X-Spam-Report: SpamAssassin version 3.3.2 on merlin.infradead.org summary: Content analysis details: (-3.3 points) pts rule name description ---- ---------------------- -------------------------------------------------- -0.7 RCVD_IN_DNSWL_LOW RBL: Sender listed at http://www.dnswl.org/, low trust [91.189.89.112 listed in list.dnswl.org] -0.7 RP_MATCHES_RCVD Envelope sender domain matches handover relay domain -1.9 BAYES_00 BODY: Bayes spam probability is 0 to 1% [score: 0.0000] Cc: Luis Henriques , linux-mtd@lists.infradead.org, Linus Torvalds , David Woodhouse X-BeenThere: linux-mtd@lists.infradead.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: Linux MTD discussion mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , MIME-Version: 1.0 Sender: "linux-mtd" Errors-To: linux-mtd-bounces+incoming=patchwork.ozlabs.org@lists.infradead.org 3.5.7.11 -stable review patch. If anyone has any objections, please let me know. ------------------ From: Linus Torvalds commit 9c603e53d380459fb62fec7cd085acb0b74ac18f upstream. Sasha Levin has been running trinity in a KVM tools guest, and was able to trigger the BUG_ON() at arch/x86/mm/pat.c:279 (verifying the range of the memory type). The call trace showed that it was mtdchar_mmap() that created an invalid remap_pfn_range(). The problem is that mtdchar_mmap() does various really odd and subtle things with the vma page offset etc, and uses the wrong types (and the wrong overflow) detection for it. For example, the page offset may well be 32-bit on a 32-bit architecture, but after shifting it up by PAGE_SHIFT, we need to use a potentially 64-bit resource_size_t to correctly hold the full value. Also, we need to check that the vma length plus offset doesn't overflow before we check that it is smaller than the length of the mtdmap region. This fixes things up and tries to make the code a bit easier to read. Reported-and-tested-by: Sasha Levin Acked-by: Suresh Siddha Acked-by: Artem Bityutskiy Cc: David Woodhouse Cc: linux-mtd@lists.infradead.org Signed-off-by: Linus Torvalds Signed-off-by: Luis Henriques --- drivers/mtd/mtdchar.c | 48 ++++++++++++++++++++++++++++++++++++++++++------ 1 file changed, 42 insertions(+), 6 deletions(-) diff --git a/drivers/mtd/mtdchar.c b/drivers/mtd/mtdchar.c index f2f482b..a6e7451 100644 --- a/drivers/mtd/mtdchar.c +++ b/drivers/mtd/mtdchar.c @@ -1123,6 +1123,33 @@ static unsigned long mtdchar_get_unmapped_area(struct file *file, } #endif +static inline unsigned long get_vm_size(struct vm_area_struct *vma) +{ + return vma->vm_end - vma->vm_start; +} + +static inline resource_size_t get_vm_offset(struct vm_area_struct *vma) +{ + return (resource_size_t) vma->vm_pgoff << PAGE_SHIFT; +} + +/* + * Set a new vm offset. + * + * Verify that the incoming offset really works as a page offset, + * and that the offset and size fit in a resource_size_t. + */ +static inline int set_vm_offset(struct vm_area_struct *vma, resource_size_t off) +{ + pgoff_t pgoff = off >> PAGE_SHIFT; + if (off != (resource_size_t) pgoff << PAGE_SHIFT) + return -EINVAL; + if (off + get_vm_size(vma) - 1 < off) + return -EINVAL; + vma->vm_pgoff = pgoff; + return 0; +} + /* * set up a mapping for shared memory segments */ @@ -1132,20 +1159,29 @@ static int mtdchar_mmap(struct file *file, struct vm_area_struct *vma) struct mtd_file_info *mfi = file->private_data; struct mtd_info *mtd = mfi->mtd; struct map_info *map = mtd->priv; - unsigned long start; - unsigned long off; - u32 len; + resource_size_t start, off; + unsigned long len, vma_len; if (mtd->type == MTD_RAM || mtd->type == MTD_ROM) { - off = vma->vm_pgoff << PAGE_SHIFT; + off = get_vm_offset(vma); start = map->phys; len = PAGE_ALIGN((start & ~PAGE_MASK) + map->size); start &= PAGE_MASK; - if ((vma->vm_end - vma->vm_start + off) > len) + vma_len = get_vm_size(vma); + + /* Overflow in off+len? */ + if (vma_len + off < off) + return -EINVAL; + /* Does it fit in the mapping? */ + if (vma_len + off > len) return -EINVAL; off += start; - vma->vm_pgoff = off >> PAGE_SHIFT; + /* Did that overflow? */ + if (off < start) + return -EINVAL; + if (set_vm_offset(vma, off) < 0) + return -EINVAL; vma->vm_flags |= VM_IO | VM_RESERVED; #ifdef pgprot_noncached