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=-10.1 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,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 3D9D6C3A59E for ; Tue, 20 Aug 2019 13:45:39 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 083B72087E for ; Tue, 20 Aug 2019 13:45:39 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1566308739; bh=aajKa75DWIkCGFrjXlLt3VAMK12kJS2v67DZm6AeF6I=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=GK31XDbC8g+5cS82zg8E4miZmxm5BzA/c4iaqLYZj70bzjy60UNWAwDl9SAZX/Fxv cAyZPhdHJt9uuknUPL5jlv7GxVTIPoBrpPDq+ofJcl0/m+8g+08tfFmtXt+YwCE7B2 ldGeArwlY13WkP55fMLVwaX1P5HI5L1RQJKx2Y8M= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730292AbfHTNpi (ORCPT ); Tue, 20 Aug 2019 09:45:38 -0400 Received: from mail.kernel.org ([198.145.29.99]:37940 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730224AbfHTNme (ORCPT ); Tue, 20 Aug 2019 09:42:34 -0400 Received: from sasha-vm.mshome.net (unknown [12.236.144.82]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 3B97422DBF; Tue, 20 Aug 2019 13:42:33 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1566308553; bh=aajKa75DWIkCGFrjXlLt3VAMK12kJS2v67DZm6AeF6I=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=et7QvWGf5FR+qek/enBuh4fRD+u8uhqp8/pPfQ6Kc9dx4azuiKVLm3etnwYPSuvSb /XlCkl/ktFL4TqCXgkmGByIT3HYhhX1vt1TC3DkETOY1azRSR0hXvLSH1lKXbdqmTr N8IPlP7av7Q7XQIcVMuD/rEtDR2Y/Hsmc8hx/Ksk= From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Robin Murphy , Nicolin Chen , Joerg Roedel , Sasha Levin , iommu@lists.linux-foundation.org Subject: [PATCH AUTOSEL 4.19 17/27] iommu/dma: Handle SG length overflow better Date: Tue, 20 Aug 2019 09:42:03 -0400 Message-Id: <20190820134213.11279-17-sashal@kernel.org> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20190820134213.11279-1-sashal@kernel.org> References: <20190820134213.11279-1-sashal@kernel.org> MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore Content-Transfer-Encoding: 8bit Sender: stable-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Robin Murphy [ Upstream commit ab2cbeb0ed301a9f0460078e91b09f39958212ef ] Since scatterlist dimensions are all unsigned ints, in the relatively rare cases where a device's max_segment_size is set to UINT_MAX, then the "cur_len + s_length <= max_len" check in __finalise_sg() will always return true. As a result, the corner case of such a device mapping an excessively large scatterlist which is mergeable to or beyond a total length of 4GB can lead to overflow and a bogus truncated dma_length in the resulting segment. As we already assume that any single segment must be no longer than max_len to begin with, this can easily be addressed by reshuffling the comparison. Fixes: 809eac54cdd6 ("iommu/dma: Implement scatterlist segment merging") Reported-by: Nicolin Chen Tested-by: Nicolin Chen Signed-off-by: Robin Murphy Signed-off-by: Joerg Roedel Signed-off-by: Sasha Levin --- drivers/iommu/dma-iommu.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/iommu/dma-iommu.c b/drivers/iommu/dma-iommu.c index 511ff9a1d6d94..f9dbb064f9571 100644 --- a/drivers/iommu/dma-iommu.c +++ b/drivers/iommu/dma-iommu.c @@ -675,7 +675,7 @@ static int __finalise_sg(struct device *dev, struct scatterlist *sg, int nents, * - and wouldn't make the resulting output segment too long */ if (cur_len && !s_iova_off && (dma_addr & seg_mask) && - (cur_len + s_length <= max_len)) { + (max_len - cur_len >= s_length)) { /* ...then concatenate it with the previous one */ cur_len += s_length; } else { -- 2.20.1