From nobody Fri Nov 7 12:34:54 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=linaro.org Return-Path: Received: from lists.gnu.org (lists.gnu.org [208.118.235.17]) by mx.zohomail.com with SMTPS id 1539106019677345.82553172683777; Tue, 9 Oct 2018 10:26:59 -0700 (PDT) Received: from localhost ([::1]:53058 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1g9vmS-0005aB-0T for importer@patchew.org; Tue, 09 Oct 2018 13:26:48 -0400 Received: from eggs.gnu.org ([2001:4830:134:3::10]:46575) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1g9vkq-0004dW-Qg for qemu-devel@nongnu.org; Tue, 09 Oct 2018 13:25:09 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1g9vkq-00055V-1Y for qemu-devel@nongnu.org; Tue, 09 Oct 2018 13:25:08 -0400 Received: from orth.archaic.org.uk ([2001:8b0:1d0::2]:51720) by eggs.gnu.org with esmtps (TLS1.0:RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1g9vkp-00053d-QP; Tue, 09 Oct 2018 13:25:07 -0400 Received: from pm215 by orth.archaic.org.uk with local (Exim 4.89) (envelope-from ) id 1g9vko-00054C-6n; Tue, 09 Oct 2018 18:25:06 +0100 From: Peter Maydell To: qemu-devel@nongnu.org Date: Tue, 9 Oct 2018 18:25:00 +0100 Message-Id: <20181009172501.17353-3-peter.maydell@linaro.org> X-Mailer: git-send-email 2.19.0 In-Reply-To: <20181009172501.17353-1-peter.maydell@linaro.org> References: <20181009172501.17353-1-peter.maydell@linaro.org> MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-detected-operating-system: by eggs.gnu.org: Genre and OS details not recognized. X-Received-From: 2001:8b0:1d0::2 Subject: [Qemu-devel] [PATCH 2/3] block/qcow: Don't take address of fields in packed structs 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-block@nongnu.org, Max Reitz Errors-To: qemu-devel-bounces+importer=patchew.org@nongnu.org Sender: "Qemu-devel" X-ZohoMail: RDMRC_1 RSF_0 Z_629925259 SPT_0 Content-Type: text/plain; charset="utf-8" Taking the address of a field in a packed struct is a bad idea, because it might not be actually aligned enough for that pointer type (and thus cause a crash on dereference on some host architectures). Newer versions of clang warn about this. Avoid the bug by not using the "modify in place" byte swapping functions. There are a few places where the in-place swap function is used on something other than a packed struct field; we convert those anyway, for consistency. This patch was produced with the following spatch script: @@ expression E; @@ -be16_to_cpus(&E); +E =3D be16_to_cpu(E); @@ expression E; @@ -be32_to_cpus(&E); +E =3D be32_to_cpu(E); @@ expression E; @@ -be64_to_cpus(&E); +E =3D be64_to_cpu(E); @@ expression E; @@ -cpu_to_be16s(&E); +E =3D cpu_to_be16(E); @@ expression E; @@ -cpu_to_be32s(&E); +E =3D cpu_to_be32(E); @@ expression E; @@ -cpu_to_be64s(&E); +E =3D cpu_to_be64(E); Signed-off-by: Peter Maydell --- block/qcow.c | 18 +++++++++--------- 1 file changed, 9 insertions(+), 9 deletions(-) diff --git a/block/qcow.c b/block/qcow.c index 385d935258f..4518cb4c35e 100644 --- a/block/qcow.c +++ b/block/qcow.c @@ -140,14 +140,14 @@ static int qcow_open(BlockDriverState *bs, QDict *opt= ions, int flags, if (ret < 0) { goto fail; } - be32_to_cpus(&header.magic); - be32_to_cpus(&header.version); - be64_to_cpus(&header.backing_file_offset); - be32_to_cpus(&header.backing_file_size); - be32_to_cpus(&header.mtime); - be64_to_cpus(&header.size); - be32_to_cpus(&header.crypt_method); - be64_to_cpus(&header.l1_table_offset); + header.magic =3D be32_to_cpu(header.magic); + header.version =3D be32_to_cpu(header.version); + header.backing_file_offset =3D be64_to_cpu(header.backing_file_offset); + header.backing_file_size =3D be32_to_cpu(header.backing_file_size); + header.mtime =3D be32_to_cpu(header.mtime); + header.size =3D be64_to_cpu(header.size); + header.crypt_method =3D be32_to_cpu(header.crypt_method); + header.l1_table_offset =3D be64_to_cpu(header.l1_table_offset); =20 if (header.magic !=3D QCOW_MAGIC) { error_setg(errp, "Image not in qcow format"); @@ -270,7 +270,7 @@ static int qcow_open(BlockDriverState *bs, QDict *optio= ns, int flags, } =20 for(i =3D 0;i < s->l1_size; i++) { - be64_to_cpus(&s->l1_table[i]); + s->l1_table[i] =3D be64_to_cpu(s->l1_table[i]); } =20 /* alloc L2 cache (max. 64k * 16 * 8 =3D 8 MB) */ --=20 2.19.0