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 DF0B2C3A59D for ; Tue, 20 Aug 2019 13:43:24 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id A66EA22DBF for ; Tue, 20 Aug 2019 13:43:24 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1566308604; bh=VFt+3yrRV/54bT3zwv9JShdoQYuWiOlyC5hzlGGNJcQ=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=x3ziPifijoRTngdrIp+PYwxip9X9i2LFdcTFNv+CZ2SjoaPzB63XFKoSrBReVSuWh b2ZZAXQXhlyY9rsYvMc9WUgQWSJQsgHk45ole25w54w2WPwvgDyqJQ+45Xp94jTtT1 hc01EsIvoRoP62GnQT1xGOzIpQ3ILF7TNuOZZ3Sk= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730853AbfHTNnX (ORCPT ); Tue, 20 Aug 2019 09:43:23 -0400 Received: from mail.kernel.org ([198.145.29.99]:39046 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730820AbfHTNnS (ORCPT ); Tue, 20 Aug 2019 09:43:18 -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 88F982332A; Tue, 20 Aug 2019 13:43:17 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1566308598; bh=VFt+3yrRV/54bT3zwv9JShdoQYuWiOlyC5hzlGGNJcQ=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=gDzH5UxV4i0Z6RysAQdFTshjoJnGWsa4WoENk4gVZDXQdizxIFtgVWW0ZQPNqUFDm Ahb4BLKghrHAAX73buRfGG/ju3891mZuznVq15G6Fuho5OB+K2WtOk1/o0j2tqw05s b+6wg5eIaewOtR2FJlyWYKmSvIuFAVZb9wVsMiNY= 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 4.9 2/7] iommu/dma: Handle SG length overflow better Date: Tue, 20 Aug 2019 09:43:10 -0400 Message-Id: <20190820134315.11720-2-sashal@kernel.org> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20190820134315.11720-1-sashal@kernel.org> References: <20190820134315.11720-1-sashal@kernel.org> MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@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 1520e7f02c2f1..89d191b6a0e0f 100644 --- a/drivers/iommu/dma-iommu.c +++ b/drivers/iommu/dma-iommu.c @@ -493,7 +493,7 @@ 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