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From: Paolo Bonzini <pbonzini@redhat.com>
To: qemu-devel@nongnu.org
Cc: zyy4013@stu.ouc.edu.cn, ppandit@redhat.com, hare@suse.de
Subject: [Qemu-devel] [PATCH 2/7] megasas: do not read sense length more than once from frame
Date: Tue,  6 Jun 2017 14:17:42 +0200	[thread overview]
Message-ID: <20170606121747.25356-3-pbonzini@redhat.com> (raw)
In-Reply-To: <20170606121747.25356-1-pbonzini@redhat.com>

Avoid TOC-TOU bugs depending on how the compiler behaves.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
---
 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

  parent reply	other threads:[~2017-06-06 12:18 UTC|newest]

Thread overview: 11+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-06-06 12:17 [Qemu-devel] [PATCH 0/7] megasas: fix TOCTOU and segmentation fault bugs Paolo Bonzini
2017-06-06 12:17 ` [Qemu-devel] [PATCH 1/7] megasas: add qtest Paolo Bonzini
2017-06-06 12:17 ` Paolo Bonzini [this message]
2017-06-06 13:26   ` [Qemu-devel] [PATCH 2/7] megasas: do not read sense length more than once from frame Philippe Mathieu-Daudé
2017-06-06 13:33     ` Paolo Bonzini
2017-06-06 12:17 ` [Qemu-devel] [PATCH 3/7] megasas: do not read iovec count " Paolo Bonzini
2017-06-06 12:17 ` [Qemu-devel] [PATCH 4/7] megasas: do not read DCMD opcode " Paolo Bonzini
2017-06-06 12:17 ` [Qemu-devel] [PATCH 5/7] megasas: do not read command " Paolo Bonzini
2017-06-06 12:17 ` [Qemu-devel] [PATCH 6/7] megasas: do not read SCSI req parameters " Paolo Bonzini
2017-06-06 12:17 ` [Qemu-devel] [PATCH 7/7] megasas: always store SCSIRequest* into MegasasCmd Paolo Bonzini
2017-06-06 17:07 ` [Qemu-devel] [PATCH 0/7] megasas: fix TOCTOU and segmentation fault bugs no-reply

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