scsi: fix buffer overflow in scsi_req_parse_cdb (CVE-2015-5158)

This is a guest-triggerable buffer overflow present in QEMU 2.2.0
and newer.  scsi_cdb_length returns -1 as an error value, but the
caller does not check it.

Luckily, the massive overflow means that QEMU will just SIGSEGV,
making the impact much smaller.

Reported-by: Zhu Donghai (朱东海) <donghai.zdh@alibaba-inc.com>
Fixes: 1894df0281
Reviewed-by: Fam Zheng <famz@redhat.com>
Cc: qemu-stable@nongnu.org
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
This commit is contained in:
Paolo Bonzini 2015-07-21 08:59:39 +02:00
parent 60928458e5
commit c170aad8b0

View file

@ -1239,10 +1239,15 @@ int scsi_cdb_length(uint8_t *buf) {
int scsi_req_parse_cdb(SCSIDevice *dev, SCSICommand *cmd, uint8_t *buf)
{
int rc;
int len;
cmd->lba = -1;
cmd->len = scsi_cdb_length(buf);
len = scsi_cdb_length(buf);
if (len < 0) {
return -1;
}
cmd->len = len;
switch (dev->type) {
case TYPE_TAPE:
rc = scsi_req_stream_xfer(cmd, dev, buf);