From patchwork Fri Jan 3 18:47:40 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Cengiz Can X-Patchwork-Id: 11317337 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 724B8921 for ; Fri, 3 Jan 2020 18:48:43 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 54FF6215A4 for ; Fri, 3 Jan 2020 18:48:43 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728355AbgACSsm (ORCPT ); Fri, 3 Jan 2020 13:48:42 -0500 Received: from relay4-d.mail.gandi.net ([217.70.183.196]:40255 "EHLO relay4-d.mail.gandi.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728279AbgACSsm (ORCPT ); Fri, 3 Jan 2020 13:48:42 -0500 X-Originating-IP: 176.88.138.87 Received: from localhost.localdomain (unknown [176.88.138.87]) (Authenticated sender: cengiz@kernel.wtf) by relay4-d.mail.gandi.net (Postfix) with ESMTPSA id DDBC8E0005; Fri, 3 Jan 2020 18:48:38 +0000 (UTC) From: Cengiz Can To: linux-btrfs@vger.kernel.org, Chris Mason , Josef Bacik , David Sterba Cc: Cengiz Can Subject: [PATCH] fs: btrfs: prevent unintentional int overflow Date: Fri, 3 Jan 2020 13:47:40 -0500 Message-Id: <20200103184739.26903-1-cengiz@kernel.wtf> X-Mailer: git-send-email 2.20.1 MIME-Version: 1.0 Sender: linux-btrfs-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-btrfs@vger.kernel.org Coverity scan for 5.5.0-rc4 found a possible integer overflow in tree-checker.c line 364. `prev_csum_end = (prev_item_size / csumsize) * sectorsize;` Quoting from scan results: ``` CID 1456959 Unintentional integer overflow Unintentional integer overflow (OVERFLOW_BEFORE_WIDEN) overflow_before_widen: Potentially overflowing expression `prev_item_size / csumsize * sectorsize` with type unsigned int (32 bits, unsigned) is evaluated using 32-bit arithmetic, and then used in a context that expects an expression of type u64. (64 bits, unsigned). ``` Added a cast to `u64` on the left hand side of the expression. Compiles fine on x86_64_defconfig with all btrfs config flags enabled. Signed-off-by: Cengiz Can --- fs/btrfs/tree-checker.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/fs/btrfs/tree-checker.c b/fs/btrfs/tree-checker.c index 97f3520b8d98..9f58f07be779 100644 --- a/fs/btrfs/tree-checker.c +++ b/fs/btrfs/tree-checker.c @@ -361,7 +361,7 @@ static int check_csum_item(struct extent_buffer *leaf, struct btrfs_key *key, u32 prev_item_size; prev_item_size = btrfs_item_size_nr(leaf, slot - 1); - prev_csum_end = (prev_item_size / csumsize) * sectorsize; + prev_csum_end = (u64) (prev_item_size / csumsize) * sectorsize; prev_csum_end += prev_key->offset; if (prev_csum_end > key->offset) { generic_err(leaf, slot - 1,