From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:56941) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1dIDQu-0001tR-Ia for qemu-devel@nongnu.org; Tue, 06 Jun 2017 08:18:01 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1dIDQq-0005FT-J8 for qemu-devel@nongnu.org; Tue, 06 Jun 2017 08:18:00 -0400 Received: from mx1.redhat.com ([209.132.183.28]:36589) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1dIDQq-0005EY-DL for qemu-devel@nongnu.org; Tue, 06 Jun 2017 08:17:56 -0400 From: Paolo Bonzini Date: Tue, 6 Jun 2017 14:17:42 +0200 Message-Id: <20170606121747.25356-3-pbonzini@redhat.com> In-Reply-To: <20170606121747.25356-1-pbonzini@redhat.com> References: <20170606121747.25356-1-pbonzini@redhat.com> Subject: [Qemu-devel] [PATCH 2/7] megasas: do not read sense length more than once from frame List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel@nongnu.org Cc: zyy4013@stu.ouc.edu.cn, ppandit@redhat.com, hare@suse.de Avoid TOC-TOU bugs depending on how the compiler behaves. Signed-off-by: Paolo Bonzini --- hw/scsi/megasas.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) diff --git a/hw/scsi/megasas.c b/hw/scsi/megasas.c index 804122ab05..1888118e5f 100644 --- a/hw/scsi/megasas.c +++ b/hw/scsi/megasas.c @@ -309,9 +309,11 @@ static int megasas_build_sense(MegasasCmd *cmd, uint8_t *sense_ptr, PCIDevice *pcid = PCI_DEVICE(cmd->state); uint32_t pa_hi = 0, pa_lo; hwaddr pa; + int frame_sense_len; - if (sense_len > cmd->frame->header.sense_len) { - sense_len = cmd->frame->header.sense_len; + frame_sense_len = cmd->frame->header.sense_len; + if (sense_len > frame_sense_len) { + sense_len = frame_sense_len; } if (sense_len) { pa_lo = le32_to_cpu(cmd->frame->pass.sense_addr_lo); -- 2.13.0