From: Paolo Bonzini Date: Thu, 1 Jun 2017 17:18:39 +0200 Subject: [PATCH] megasas: do not read sense length more than once from frame Avoid TOC-TOU bugs depending on how the compiler behaves. Signed-off-by: Paolo Bonzini (cherry picked from commit 134550bf81a026e18cf58b81e2c2cceaf516f92e) --- 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);