megasas: use unsigned type for reply_queue_head and check index
A guest user may set 'reply_queue_head' field of MegasasState to
a negative value. Later in 'megasas_lookup_frame' it is used to
index into s->frames[] array. Use unsigned type to avoid OOB
access issue.
Also check that 'index' value stays within s->frames[] bounds
through the while() loop in 'megasas_lookup_frame' to avoid OOB
access.
Reported-by: Ren Ding <rding@gatech.edu>
Reported-by: Hanqing Zhao <hanqing@gatech.edu>
Reported-by: Alexander Bulekov <alxndr@bu.edu>
Signed-off-by: Prasad J Pandit <pjp@fedoraproject.org>
Acked-by: Alexander Bulekov <alxndr@bu.edu>
Message-Id: <20200513192540.1583887-2-ppandit@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
diff --git a/hw/scsi/megasas.c b/hw/scsi/megasas.c
index af18c88..6ce598c 100644
--- a/hw/scsi/megasas.c
+++ b/hw/scsi/megasas.c
@@ -112,7 +112,7 @@
uint64_t reply_queue_pa;
void *reply_queue;
int reply_queue_len;
- int reply_queue_head;
+ uint16_t reply_queue_head;
int reply_queue_tail;
uint64_t consumer_pa;
uint64_t producer_pa;
@@ -445,7 +445,7 @@
index = s->reply_queue_head;
- while (num < s->fw_cmds) {
+ while (num < s->fw_cmds && index < MEGASAS_MAX_FRAMES) {
if (s->frames[index].pa && s->frames[index].pa == frame) {
cmd = &s->frames[index];
break;
