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....@alibaba-inc.com>
Fixes: 1894df02811f6b79ea3ffbf1084599d96f316173
Reviewed-by: Fam Zheng <f...@redhat.com>
Cc: qemu-sta...@nongnu.org
Signed-off-by: Paolo Bonzini <pbonz...@redhat.com>
---
hw/scsi/scsi-bus.c | 7 ++++++-
1 file changed, 6 insertions(+), 1 deletion(-)
diff --git a/hw/scsi/scsi-bus.c b/hw/scsi/scsi-bus.c
index f50b2f0..f0ae462 100644
--- a/hw/scsi/scsi-bus.c
+++ b/hw/scsi/scsi-bus.c
@@ -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);
--
2.4.3
