scsi_target_send_command(): amend stable-1.6 port of the CVE-2013-4344 fix
The originally suggested fix for CVE-2013-4344 introduced a regression in
scsi_target_send_command() / REQUEST_SENSE; the third argument passed to
scsi_device_get_sense() -- for the "len" parameter -- ignored the
possibility of the guest SCSI driver requesting truncated (or shorter than
full) sense data.
This could result in (r->len > req->cmd.xfer) on return, which is not
valid SCSI.
The problem was addressed in the second round, and the commit on the
master branch (84642435) is correct. However the stable-1.6 branch (the
v1.6.1 release) has the original, regressive fix (commit fdcbe7d5); let's
update it.
Signed-off-by: Laszlo Ersek <lersek@redhat.com>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Michael Roth <mdroth@linux.vnet.ibm.com>
diff --git a/hw/scsi/scsi-bus.c b/hw/scsi/scsi-bus.c
index ad26c25..d352da7 100644
--- a/hw/scsi/scsi-bus.c
+++ b/hw/scsi/scsi-bus.c
@@ -460,7 +460,8 @@
break;
case REQUEST_SENSE:
scsi_target_alloc_buf(&r->req, SCSI_SENSE_LEN);
- r->len = scsi_device_get_sense(r->req.dev, r->buf, r->buf_len,
+ r->len = scsi_device_get_sense(r->req.dev, r->buf,
+ MIN(req->cmd.xfer, r->buf_len),
(req->cmd.buf[1] & 1) == 0);
if (r->req.dev->sense_is_ua) {
scsi_device_unit_attention_reported(req->dev);
