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=-19.1 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,USER_AGENT_GIT autolearn=unavailable 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 04934C433F5 for ; Thu, 9 Sep 2021 16:14:19 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id E1DD760F58 for ; Thu, 9 Sep 2021 16:14:18 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234314AbhIIQP0 (ORCPT ); Thu, 9 Sep 2021 12:15:26 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:40364 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232192AbhIIQPZ (ORCPT ); Thu, 9 Sep 2021 12:15:25 -0400 Received: from mail-pl1-x62d.google.com (mail-pl1-x62d.google.com [IPv6:2607:f8b0:4864:20::62d]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id E26F2C061574 for ; Thu, 9 Sep 2021 09:14:15 -0700 (PDT) Received: by mail-pl1-x62d.google.com with SMTP id l11so1377795plk.6 for ; Thu, 09 Sep 2021 09:14:15 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=chromium.org; s=google; h=from:to:cc:subject:date:message-id:mime-version :content-transfer-encoding; bh=1JGe4D2wjFUfPd6vacYx/JXO6F3wkweoltx6Dqf7HcU=; b=QIqfTWdnhHkMYropAtc5L/CGOqbBtD2oaxfwL0irPS5uuhbKq0VHC/EdOES8zCc7y9 eDSkwfUxkzfCTk53qTHdGV8HbWHDfsKVnGhz92F6lwXXoDbfPtYHySzcJ6MD90Bk7IZn t+Ztf7hqWNxjuhP/EgYohW2gDLqqGeY91Yi+g= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:from:to:cc:subject:date:message-id:mime-version :content-transfer-encoding; bh=1JGe4D2wjFUfPd6vacYx/JXO6F3wkweoltx6Dqf7HcU=; b=LaBGi5AVdWuWlHWQ5DMQfmDK0BwWBXfJre6/IWSiAW7vCUJnJfPSNobhxtUKOiI1tN USlGGkOVuTYDTTIf+9fpKO+c5pryjWgtfQVjTX6cAafd6vtN+sfLaQrb/E6kNrbuwuPt v32Wm8UJ/eFp7iz0GZGOqZsY+OeaSAwbq+q+pQ8yP2Q1IjM65XgSox536oi2FEjOQdOC BZyaJMYkupKsfDNVUBd9MHbIftbya4lAdKGktN30Nyc+tlQW75/oA0+4tO4mup+vIMKM unAcWmtowfrp5YfHXl4vle8wTMiac/IYlKWMDWSMtJ0AKVEltvVoj8KInmSNEojJUl0V 6ahw== X-Gm-Message-State: AOAM53240f0Ou8GGz4fco9g+51qAlzAjRtmFSSO4U5rBUhdZs/obM4Q6 wuvY8HWWv/U/nOUEcztvHDTuMg== X-Google-Smtp-Source: ABdhPJyRLRkbM2YiR/gGbNNvha2UwrK1QhPP0hjYQxgvP/YlN9gWgEqi62vB80VuAEUW/ciKYDsiEw== X-Received: by 2002:a17:902:d895:b0:13a:2789:d5a with SMTP id b21-20020a170902d89500b0013a27890d5amr3406615plz.38.1631204055025; Thu, 09 Sep 2021 09:14:15 -0700 (PDT) Received: from www.outflux.net (smtp.outflux.net. [198.145.64.163]) by smtp.gmail.com with ESMTPSA id q29sm3113782pgc.91.2021.09.09.09.14.14 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 09 Sep 2021 09:14:14 -0700 (PDT) From: Kees Cook To: Andrew Morton Cc: Kees Cook , kernel test robot , Matt Porter , Alexandre Bounine , Jing Xiangfeng , Ira Weiny , John Hubbard , Souptick Joarder , "Gustavo A . R . Silva" , Dan Carpenter , linux-kernel@vger.kernel.org, linux-hardening@vger.kernel.org Subject: [PATCH] rapidio: Avoid bogus __alloc_size warning Date: Thu, 9 Sep 2021 09:14:09 -0700 Message-Id: <20210909161409.2250920-1-keescook@chromium.org> X-Mailer: git-send-email 2.30.2 MIME-Version: 1.0 X-Developer-Signature: v=1; a=openpgp-sha256; l=3491; h=from:subject; bh=P1lUMvX1H8HLf+qzdl7h1sq7hz8im87SJa/BT7GjmDw=; b=owEBbQKS/ZANAwAKAYly9N/cbcAmAcsmYgBhOjLQzNf+JyoFp+8+uFIn0W83GW4rwhl8RZ9NWo0X sug5K4WJAjMEAAEKAB0WIQSlw/aPIp3WD3I+bhOJcvTf3G3AJgUCYToy0AAKCRCJcvTf3G3AJlQMD/ 93Y1qYVZrgypPvqY4Ut8xrc9WPQh8jQr3gaJrPLNVdI8CIJbjOfG9r+GLul4bA8p6S6i9K9AJpW1Si rlA1aUZkDijoa39HxUhmk9oolXNJC5YwsYYTMaqWkqZoYHbllNdSsLCRbp1jvsd6XvfDXaQ1xS4ucK ah+920AoEV2Lg7mr/OD//SG4q5EJZUsZRo0xrspuDbm+LviTZw4FxtYt9gVW2/FBz2whkCTjm4N+Wv IbiVkq2w84BGWFrqroWKlb7qFx4MwpoPVLXCFuBLGXLH1KFyS/jw557QHJ7aF0fsMEvJDLBzyViUOF hP36PYx9mw1zsQXYzjzH5M/W6uDNdr5qfpkmbsZG9mcxOXXMJ7zdGPcZZ0ac+g2D4aLaSu7OZ9GF6r ADlOcsSbOBh+ltzulhM37Oglt4aiPZ98VW+STqkB7duh27Vn2mI9+xcMXQVPYajVD7j9GZBlUcM8Sz 8CJuwNY53M6k3lPoskUx70sKJ6DTt2m3QItXCM+pMyUr9DJIeUm7j8FDsdSANbnzTlS6uDofwzvZFP yDbE6V2zJ4vgEEf0Wq2Q8ZGo6ji25hYkzQR8tPsXB1ePTyxsd9Gu2VsqnLaPDOSRc81tir7mXDqjnb s5BN+ExnjUek2OEGRonGWWSKfMHuUXxiVHxbWuGBMAx9BbImUewNbKXS9xyg== X-Developer-Key: i=keescook@chromium.org; a=openpgp; fpr=A5C3F68F229DD60F723E6E138972F4DFDC6DC026 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org GCC 9.3 (but not later) incorrectly evaluates the arguments to check_copy_size(), getting seemingly confused by the size being returned from array_size(). Instead, perform the calculation once, which both makes the code more readable and avoids the bug in GCC. In file included from arch/x86/include/asm/preempt.h:7, from include/linux/preempt.h:78, from include/linux/spinlock.h:55, from include/linux/mm_types.h:9, from include/linux/buildid.h:5, from include/linux/module.h:14, from drivers/rapidio/devices/rio_mport_cdev.c:13: In function 'check_copy_size', inlined from 'copy_from_user' at include/linux/uaccess.h:191:6, inlined from 'rio_mport_transfer_ioctl' at drivers/rapidio/devices/rio_mport_cdev.c:983:6: include/linux/thread_info.h:213:4: error: call to '__bad_copy_to' declared with attribute error: copy destination size is too small 213 | __bad_copy_to(); | ^~~~~~~~~~~~~~~ But the allocation size and the copy size are identical: transfer = vmalloc(array_size(sizeof(*transfer), transaction.count)); if (!transfer) return -ENOMEM; if (unlikely(copy_from_user(transfer, (void __user *)(uintptr_t)transaction.block, array_size(sizeof(*transfer), transaction.count)))) { Reported-by: kernel test robot Link: https://lore.kernel.org/linux-mm/202109091134.FHnRmRxu-lkp@intel.com/ Cc: Matt Porter Cc: Alexandre Bounine Cc: Jing Xiangfeng Cc: Ira Weiny Cc: John Hubbard Cc: Souptick Joarder Cc: Gustavo A. R. Silva Signed-off-by: Kees Cook --- drivers/rapidio/devices/rio_mport_cdev.c | 9 +++++---- 1 file changed, 5 insertions(+), 4 deletions(-) diff --git a/drivers/rapidio/devices/rio_mport_cdev.c b/drivers/rapidio/devices/rio_mport_cdev.c index 94331d999d27..7df466e22282 100644 --- a/drivers/rapidio/devices/rio_mport_cdev.c +++ b/drivers/rapidio/devices/rio_mport_cdev.c @@ -965,6 +965,7 @@ static int rio_mport_transfer_ioctl(struct file *filp, void __user *arg) struct rio_transfer_io *transfer; enum dma_data_direction dir; int i, ret = 0; + size_t size; if (unlikely(copy_from_user(&transaction, arg, sizeof(transaction)))) return -EFAULT; @@ -976,13 +977,14 @@ static int rio_mport_transfer_ioctl(struct file *filp, void __user *arg) priv->md->properties.transfer_mode) == 0) return -ENODEV; - transfer = vmalloc(array_size(sizeof(*transfer), transaction.count)); + size = array_size(sizeof(*transfer), transaction.count); + transfer = vmalloc(size); if (!transfer) return -ENOMEM; if (unlikely(copy_from_user(transfer, (void __user *)(uintptr_t)transaction.block, - array_size(sizeof(*transfer), transaction.count)))) { + size))) { ret = -EFAULT; goto out_free; } @@ -994,8 +996,7 @@ static int rio_mport_transfer_ioctl(struct file *filp, void __user *arg) transaction.sync, dir, &transfer[i]); if (unlikely(copy_to_user((void __user *)(uintptr_t)transaction.block, - transfer, - array_size(sizeof(*transfer), transaction.count)))) + transfer, size))) ret = -EFAULT; out_free: -- 2.30.2