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ps2: check PS2Queue pointers in post_load routine

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During Qemu guest migration, a destination process invokes ps2
post_load function. In that, if 'rptr' and 'count' values were
invalid, it could lead to OOB access or infinite loop issue.
Add check to avoid it.

Reported-by: Cyrille Chatras <cyrille.chatras@orange.com>
Signed-off-by: Prasad J Pandit <pjp@fedoraproject.org>
Message-id: 20171116075155.22378-1-ppandit@redhat.com
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
This commit is contained in:
Prasad J Pandit 2017-11-16 13:21:55 +05:30 committed by Gerd Hoffmann
parent a5f99be41e
commit 802cbcb730
1 changed files with 9 additions and 12 deletions
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15
hw/input/ps2.c
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@ -1225,24 +1225,21 @@ static void ps2_common_reset(PS2State *s)
static void ps2_common_post_load(PS2State *s) static void ps2_common_post_load(PS2State *s)
{ {
PS2Queue *q = &s->queue; PS2Queue *q = &s->queue;
int size; uint8_t i, size;
int i; uint8_t tmp_data[PS2_QUEUE_SIZE];
int tmp_data[PS2_QUEUE_SIZE];
/* set the useful data buffer queue size, < PS2_QUEUE_SIZE */ /* set the useful data buffer queue size, < PS2_QUEUE_SIZE */
size = q->count > PS2_QUEUE_SIZE ? 0 : q->count; size = (q->count < 0 || q->count > PS2_QUEUE_SIZE) ? 0 : q->count;
/* move the queue elements to the start of data array */ /* move the queue elements to the start of data array */
if (size > 0) {
for (i = 0; i < size; i++) { for (i = 0; i < size; i++) {
/* move the queue elements to the temporary buffer */ if (q->rptr < 0 || q->rptr >= sizeof(q->data)) {
tmp_data[i] = q->data[q->rptr];
if (++q->rptr == 256) {
q->rptr = 0; q->rptr = 0;
} }
tmp_data[i] = q->data[q->rptr++];
} }
memcpy(q->data, tmp_data, size); memcpy(q->data, tmp_data, size);
}
/* reset rptr/wptr/count */ /* reset rptr/wptr/count */
q->rptr = 0; q->rptr = 0;
q->wptr = size; q->wptr = size;