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megasas: use unsigned type for reply_queue_head and check index

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Git-commit: f50ab86a26
References: bsc#1172383, CVE-2020-13362

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>
Signed-off-by: Bruce Rogers <brogers@suse.com>
This commit is contained in:
Prasad J Pandit
2020-05-14 00:55:38 +05:30
committed by Bruce Rogers
parent 272680ca58
commit 7e496d88ec
1 changed files with 2 additions and 2 deletions
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4
hw/scsi/megasas.c
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@@ -111,7 +111,7 @@ typedef struct MegasasState {
uint64_t reply_queue_pa; uint64_t reply_queue_pa;
void *reply_queue; void *reply_queue;
int reply_queue_len; int reply_queue_len;
int reply_queue_head; uint16_t reply_queue_head;
int reply_queue_tail; int reply_queue_tail;
uint64_t consumer_pa; uint64_t consumer_pa;
uint64_t producer_pa; uint64_t producer_pa;
@@ -456,7 +456,7 @@ static MegasasCmd *megasas_lookup_frame(MegasasState *s,
index = s->reply_queue_head; 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) { if (s->frames[index].pa && s->frames[index].pa == frame) {
cmd = &s->frames[index]; cmd = &s->frames[index];
break; break;