From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-5.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id DE11DC64EB5 for ; Tue, 2 Oct 2018 13:27:47 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id A420C206B2 for ; Tue, 2 Oct 2018 13:27:47 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org A420C206B2 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=linuxfoundation.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728784AbeJBULG (ORCPT ); Tue, 2 Oct 2018 16:11:06 -0400 Received: from mail.linuxfoundation.org ([140.211.169.12]:60486 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728744AbeJBULG (ORCPT ); Tue, 2 Oct 2018 16:11:06 -0400 Received: from localhost (24-104-73-23-ip-static.hfc.comcastbusiness.net [24.104.73.23]) by mail.linuxfoundation.org (Postfix) with ESMTPSA id 05FF2C2B; Tue, 2 Oct 2018 13:27:43 +0000 (UTC) From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Todd Kjos , devel@driverdev.osuosl.org, kernel-team@android.com, Joel Fernandes , Alistair Strachan , Martijn Coenen , Sasha Levin Subject: [PATCH 4.18 072/228] staging: android: ashmem: Fix mmap size validation Date: Tue, 2 Oct 2018 06:22:49 -0700 Message-Id: <20181002132504.166593345@linuxfoundation.org> X-Mailer: git-send-email 2.19.0 In-Reply-To: <20181002132459.032960735@linuxfoundation.org> References: <20181002132459.032960735@linuxfoundation.org> User-Agent: quilt/0.65 X-stable: review MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 4.18-stable review patch. If anyone has any objections, please let me know. ------------------ From: Alistair Strachan [ Upstream commit 8632c614565d0c5fdde527889601c018e97b6384 ] The ashmem driver did not check that the size/offset of the vma passed to its .mmap() function was not larger than the ashmem object being mapped. This could cause mmap() to succeed, even though accessing parts of the mapping would later fail with a segmentation fault. Ensure an error is returned by the ashmem_mmap() function if the vma size is larger than the ashmem object size. This enables safer handling of the problem in userspace. Cc: Todd Kjos Cc: devel@driverdev.osuosl.org Cc: linux-kernel@vger.kernel.org Cc: kernel-team@android.com Cc: Joel Fernandes Signed-off-by: Alistair Strachan Acked-by: Joel Fernandes (Google) Reviewed-by: Martijn Coenen Signed-off-by: Greg Kroah-Hartman Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman --- drivers/staging/android/ashmem.c | 6 ++++++ 1 file changed, 6 insertions(+) --- a/drivers/staging/android/ashmem.c +++ b/drivers/staging/android/ashmem.c @@ -366,6 +366,12 @@ static int ashmem_mmap(struct file *file goto out; } + /* requested mapping size larger than object size */ + if (vma->vm_end - vma->vm_start > PAGE_ALIGN(asma->size)) { + ret = -EINVAL; + goto out; + } + /* requested protection bits must match our allowed protection mask */ if (unlikely((vma->vm_flags & ~calc_vm_prot_bits(asma->prot_mask, 0)) & calc_vm_prot_bits(PROT_MASK, 0))) {