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 <pbonzini@redhat.com>
(cherry picked from commit 134550bf81)
Signed-off-by: Michael Roth <mdroth@linux.vnet.ibm.com>
stable-2.9
Paolo Bonzini 2017-06-01 17:18:39 +02:00 committed by Michael Roth
parent 7442018a00
commit 20fd62d374
1 changed files with 4 additions and 2 deletions

View File

@ -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);