From nobody Fri Oct 24 22:15:01 2025 Delivered-To: importer@patchew.org Received-SPF: pass (zoho.com: domain of gnu.org designates 208.118.235.17 as permitted sender) client-ip=208.118.235.17; envelope-from=qemu-devel-bounces+importer=patchew.org@nongnu.org; helo=lists.gnu.org; Authentication-Results: mx.zohomail.com; spf=pass (zoho.com: domain of gnu.org designates 208.118.235.17 as permitted sender) smtp.mailfrom=qemu-devel-bounces+importer=patchew.org@nongnu.org; dmarc=fail(p=none dis=none) header.from=redhat.com Return-Path: Received: from lists.gnu.org (lists.gnu.org [208.118.235.17]) by mx.zohomail.com with SMTPS id 1519823823560432.00125984992053; Wed, 28 Feb 2018 05:17:03 -0800 (PST) Received: from localhost ([::1]:44244 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1er1bS-0002XS-Bu for importer@patchew.org; Wed, 28 Feb 2018 08:17:02 -0500 Received: from eggs.gnu.org ([2001:4830:134:3::10]:45461) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1er1Y5-0000G6-UC for qemu-devel@nongnu.org; Wed, 28 Feb 2018 08:13:34 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1er1Y4-0001vn-Oz for qemu-devel@nongnu.org; Wed, 28 Feb 2018 08:13:33 -0500 Received: from mx3-rdu2.redhat.com ([66.187.233.73]:33050 helo=mx1.redhat.com) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1er1Xy-0001tq-EF; Wed, 28 Feb 2018 08:13:26 -0500 Received: from smtp.corp.redhat.com (int-mx05.intmail.prod.int.rdu2.redhat.com [10.11.54.5]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 7290E402290A; Wed, 28 Feb 2018 13:13:23 +0000 (UTC) Received: from localhost (unknown [10.40.205.159]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 1C981946B8; Wed, 28 Feb 2018 13:13:22 +0000 (UTC) From: Max Reitz To: qemu-block@nongnu.org Date: Wed, 28 Feb 2018 14:13:14 +0100 Message-Id: <20180228131315.30194-2-mreitz@redhat.com> In-Reply-To: <20180228131315.30194-1-mreitz@redhat.com> References: <20180228131315.30194-1-mreitz@redhat.com> X-Scanned-By: MIMEDefang 2.79 on 10.11.54.5 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.11.55.6]); Wed, 28 Feb 2018 13:13:23 +0000 (UTC) X-Greylist: inspected by milter-greylist-4.5.16 (mx1.redhat.com [10.11.55.6]); Wed, 28 Feb 2018 13:13:23 +0000 (UTC) for IP:'10.11.54.5' DOMAIN:'int-mx05.intmail.prod.int.rdu2.redhat.com' HELO:'smtp.corp.redhat.com' FROM:'mreitz@redhat.com' RCPT:'' X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] [fuzzy] X-Received-From: 66.187.233.73 Subject: [Qemu-devel] [PATCH 1/2] block/file-posix: Fix fully preallocated truncate X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Kevin Wolf , qemu-stable@nongnu.org, qemu-devel@nongnu.org, Max Reitz Errors-To: qemu-devel-bounces+importer=patchew.org@nongnu.org Sender: "Qemu-devel" X-ZohoMail: RSF_0 Z_629925259 SPT_0 Content-Transfer-Encoding: quoted-printable MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Storing the lseek() result in an int results in it overflowing when the file is at least 2 GB big. Then, we have a 50 % chance of the result being "negative" and thus thinking an error occurred when actually everything went just fine. So we should use the correct type for storing the result: off_t. Reported-by: Daniel P. Berrange Buglink: https://bugzilla.redhat.com/show_bug.cgi?id=3D1549231 Cc: qemu-stable@nongnu.org Signed-off-by: Max Reitz Reviewed-by: Daniel P. Berrang=C3=A9 --- block/file-posix.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) diff --git a/block/file-posix.c b/block/file-posix.c index f1591c3849..90c25864a0 100644 --- a/block/file-posix.c +++ b/block/file-posix.c @@ -1697,6 +1697,7 @@ static int raw_regular_truncate(int fd, int64_t offse= t, PreallocMode prealloc, case PREALLOC_MODE_FULL: { int64_t num =3D 0, left =3D offset - current_length; + off_t seek_result; =20 /* * Knowing the final size from the beginning could allow the file @@ -1711,8 +1712,8 @@ static int raw_regular_truncate(int fd, int64_t offse= t, PreallocMode prealloc, =20 buf =3D g_malloc0(65536); =20 - result =3D lseek(fd, current_length, SEEK_SET); - if (result < 0) { + seek_result =3D lseek(fd, current_length, SEEK_SET); + if (seek_result < 0) { result =3D -errno; error_setg_errno(errp, -result, "Failed to seek to the old end of file"); --=20 2.14.3