From patchwork Tue Jan 23 00:26:50 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: Kees Cook X-Patchwork-Id: 98747 Received: from ny.mirrors.kernel.org ([147.75.199.223]) by www.linuxtv.org with esmtp (Exim 4.96) (envelope-from ) id 1rS5d9-0006oP-1s for patchwork@linuxtv.org; Tue, 23 Jan 2024 01:31:15 +0000 Received: from smtp.subspace.kernel.org (wormhole.subspace.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ny.mirrors.kernel.org (Postfix) with ESMTPS id ED07B1C23B7C for ; Tue, 23 Jan 2024 01:31:08 +0000 (UTC) Received: from localhost.localdomain (localhost.localdomain [127.0.0.1]) by smtp.subspace.kernel.org (Postfix) with ESMTP id 9323F15F326; Tue, 23 Jan 2024 00:36:15 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=chromium.org header.i=@chromium.org header.b="HFC2D/w8" X-Original-To: linux-media@vger.kernel.org Received: from mail-ot1-f48.google.com (mail-ot1-f48.google.com [209.85.210.48]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 1411A15EA8F for ; Tue, 23 Jan 2024 00:36:12 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.210.48 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1705970175; cv=none; b=ZrCBLbMaNDYyKq+hXSo6gopyYk/wMLbS8klOEfSmDahWFD0rDoomjGGtwzrUeHEhPHREn7FCsHp1p+zy9M9RsS1+DpF4IV46/27IEDz0aYrmoffedfz8RP7tiNoKOi/2ucivMkFlfH6uZp++aBElc8MFCNF4kBUIF98Vl0Ss/z0= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1705970175; c=relaxed/simple; bh=O50T+ehgWO04+/PTwK/XEjtbdWM1siGuxiWx5Y9VWF8=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References: MIME-Version:Content-Type; b=JjU56yMdczIqL+Lfayux8suQb09J48paukLUCqrNwuxjLmBPqt+gfeXpLZ7t1yiO0z6swb9NaTYh+bnO4bMKxb8rB5jHzUH9kpSvLMLnIYYc/cv2h4MdNvN22YBOtdQRXG78V4MuU5etArnomZXFEpbeVusbkb4KoeYoDcG8Cm8= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=chromium.org; spf=pass smtp.mailfrom=chromium.org; dkim=pass (1024-bit key) header.d=chromium.org header.i=@chromium.org header.b=HFC2D/w8; arc=none smtp.client-ip=209.85.210.48 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=chromium.org Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=chromium.org Received: by mail-ot1-f48.google.com with SMTP id 46e09a7af769-6dddb927d02so2158792a34.2 for ; Mon, 22 Jan 2024 16:36:12 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=chromium.org; s=google; t=1705970172; x=1706574972; darn=vger.kernel.org; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:from:to:cc:subject:date :message-id:reply-to; bh=SKixWzqfowMzvUX6r00bx/1VlD3LFsId3tPJIJRuIR0=; b=HFC2D/w8uclQu1y30dfKDrOf3EDdjqB5rPeIVnPGsAqsah4CP4enAkdphiBcykqKpz EAo95xODZqXsiNOS4A+vkjjOuGBI+mWHfVKsgsH/IR798pDBAST9TLl5ibXCe0VYwil3 AGFLKlu8M/+rFzg6fRtzH7YaH9yB+Xewexpk4= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1705970172; x=1706574972; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=SKixWzqfowMzvUX6r00bx/1VlD3LFsId3tPJIJRuIR0=; b=mQtREju26PTGYRkFIoAatr/+RrMJRXJiILG8nGaNL22n6jgFtdZ06z8EhtMNeMUxSy n4zBYEhYFYWpAXOLZh8knJ7YwwJyKooRbSoV3uTtviuxIGg9LvM+eZMJPoOBZhHGWKux zzXn5SW1rWANxnMM0YllLRG2r1ZIuXXmWZmuGIqZLAZnSowWj7Me4pQWcLVb6ZzpPJmA cCwoVH42LRHpLm2+zhGCgfhHyYFs/3AVdUrXmQHcPygptW4py++FzGqtCb5mDoE/h+LO q+GEvAm2gxRFM1HN4F5Meu8HaYiwXpTihyHa4IWsZydqFjRQxGxF8dVcD4d6jUPXtYMD ff0g== X-Gm-Message-State: AOJu0YzK+kL4HnfPeyM4fT8jloMABg4o7hi8zN+AfH95BRtRVn+B+FaZ Y9lvYIbzxbcdDLEkA5agHKtyFcbIDFd1UJ7+ylCJ3VVYvuAptxm4JVah4wXiog== X-Google-Smtp-Source: AGHT+IHGoYZGs2buOqQkiIhEJDExn82aWCutmrbis2Hs9LbtRGU/qouIkWFMc0AMtn7Yh4iOMq5Tmw== X-Received: by 2002:a05:6358:719:b0:176:5d0d:4c6a with SMTP id e25-20020a056358071900b001765d0d4c6amr1659265rwj.29.1705970172214; Mon, 22 Jan 2024 16:36:12 -0800 (PST) Received: from www.outflux.net ([198.0.35.241]) by smtp.gmail.com with ESMTPSA id sb12-20020a17090b50cc00b0028cef2025ddsm10440436pjb.15.2024.01.22.16.36.01 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 22 Jan 2024 16:36:08 -0800 (PST) From: Kees Cook To: linux-hardening@vger.kernel.org Cc: Kees Cook , Sumit Semwal , =?utf-8?q?Christian_K=C3=B6nig?= , linux-media@vger.kernel.org, dri-devel@lists.freedesktop.org, linaro-mm-sig@lists.linaro.org, "Gustavo A. R. Silva" , Bill Wendling , Justin Stitt , linux-kernel@vger.kernel.org Subject: [PATCH 15/82] dma-buf: Refactor intentional wrap-around calculation Date: Mon, 22 Jan 2024 16:26:50 -0800 Message-Id: <20240123002814.1396804-15-keescook@chromium.org> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20240122235208.work.748-kees@kernel.org> References: <20240122235208.work.748-kees@kernel.org> Precedence: bulk X-Mailing-List: linux-media@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Developer-Signature: v=1; a=openpgp-sha256; l=2493; i=keescook@chromium.org; h=from:subject; bh=O50T+ehgWO04+/PTwK/XEjtbdWM1siGuxiWx5Y9VWF8=; b=owEBbQKS/ZANAwAKAYly9N/cbcAmAcsmYgBlrwgFQ84pwHJOpkJM7cBBjZQ+dyB2q0GyyRoUN phvzaNFVByJAjMEAAEKAB0WIQSlw/aPIp3WD3I+bhOJcvTf3G3AJgUCZa8IBQAKCRCJcvTf3G3A Jju2D/9msHfBekreecuP9d0fYucPYwOuP/5LSP35dnh1uQL9A/+S6Af8H21MOl+me8AiycS0dk2 0Nd3au8vn2Nl78aIRV+C7DFP3rFOa3KdUfS/qJRRlEE9tAeJXHJECtKEMp7t9CehEJHacXZIT45 r8trE7qdtUW4JMqG9sya72KThUcsRNHfVbJQQ536OU9zvx/NhCHm1onTJ2C9o3h+1II4GGGKmlJ 1zJ3W0eVSeM24egFgMxHcqvYy+Cue+A5RfFDwojwaBnfmWhBtXesTBwFJTsQanPGWE9JxbSxsbz CglnWiNPjq9pDs31mtBqwR8DgmONGfQIo9NhxiQ+1Cdjx4VWvmPO49vDUmd1yNPDgbj/QxI/cRq ARVjAjmWNHxVGH0lTnwUrrDgtkF+R44Iuhdim/nvBSBZrpaG8yrRA+4NFpPtsZOwVdXMSnfI7wQ gE0joPsgazTDQFUqzcRtfyqrcvYXIeIiXdh/Y4Ej/km9tQ0/0DLxTbTCqoGtnoSuEVfvCzs+unU tfzaCnbjn45fawrtcGUb6pVdFQzPQRUw9P1lmZqDc+GxwioZP4dCvcu/bG0+essTAlw/09sdKqu O/ci8K7u1AkUc7NcLes5iGCNf8aWaXBCSkX8vB/mu6PUk7piIN/1FYcQTY+LYW8Hq5cLwHBPmQn wygzmyMo3p0bqsw== X-Developer-Key: i=keescook@chromium.org; a=openpgp; fpr=A5C3F68F229DD60F723E6E138972F4DFDC6DC026 X-LSpam-Score: -4.0 (----) X-LSpam-Report: No, score=-4.0 required=5.0 tests=ARC_SIGNED=0.001,ARC_VALID=-0.1,DKIMWL_WL_HIGH=-1,DKIM_SIGNED=0.1,DKIM_VALID=-0.1,DKIM_VALID_AU=-0.1,DMARC_PASS=-0.001,HEADER_FROM_DIFFERENT_DOMAINS=0.5,MAILING_LIST_MULTI=-1,RCVD_IN_DNSWL_MED=-2.3,SPF_HELO_NONE=0.001,SPF_PASS=-0.001 autolearn=ham autolearn_force=no In an effort to separate intentional arithmetic wrap-around from unexpected wrap-around, we need to refactor places that depend on this kind of math. One of the most common code patterns of this is: VAR + value < VAR Notably, this is considered "undefined behavior" for signed and pointer types, which the kernel works around by using the -fno-strict-overflow option in the build[1] (which used to just be -fwrapv). Regardless, we want to get the kernel source to the position where we can meaningfully instrument arithmetic wrap-around conditions and catch them when they are unexpected, regardless of whether they are signed[2], unsigned[3], or pointer[4] types. Refactor open-coded unsigned wrap-around addition test to use check_add_overflow(), retaining the result for later usage (which removes the redundant open-coded addition). This paves the way to enabling the wrap-around sanitizers in the future. Link: https://git.kernel.org/linus/68df3755e383e6fecf2354a67b08f92f18536594 [1] Link: https://github.com/KSPP/linux/issues/26 [2] Link: https://github.com/KSPP/linux/issues/27 [3] Link: https://github.com/KSPP/linux/issues/344 [4] Cc: Sumit Semwal Cc: Christian König Cc: "Christian König" Cc: linux-media@vger.kernel.org Cc: dri-devel@lists.freedesktop.org Cc: linaro-mm-sig@lists.linaro.org Signed-off-by: Kees Cook --- drivers/dma-buf/dma-buf.c | 7 ++++--- 1 file changed, 4 insertions(+), 3 deletions(-) diff --git a/drivers/dma-buf/dma-buf.c b/drivers/dma-buf/dma-buf.c index 8fe5aa67b167..3743c63a9b59 100644 --- a/drivers/dma-buf/dma-buf.c +++ b/drivers/dma-buf/dma-buf.c @@ -1458,6 +1458,8 @@ EXPORT_SYMBOL_NS_GPL(dma_buf_end_cpu_access, DMA_BUF); int dma_buf_mmap(struct dma_buf *dmabuf, struct vm_area_struct *vma, unsigned long pgoff) { + unsigned long sum; + if (WARN_ON(!dmabuf || !vma)) return -EINVAL; @@ -1466,12 +1468,11 @@ int dma_buf_mmap(struct dma_buf *dmabuf, struct vm_area_struct *vma, return -EINVAL; /* check for offset overflow */ - if (pgoff + vma_pages(vma) < pgoff) + if (check_add_overflow(pgoff, vma_pages(vma), &sum)) return -EOVERFLOW; /* check for overflowing the buffer's size */ - if (pgoff + vma_pages(vma) > - dmabuf->size >> PAGE_SHIFT) + if (sum > dmabuf->size >> PAGE_SHIFT) return -EINVAL; /* readjust the vma */