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From ee9a17d0e12143971a9676227cce953c0dbe52fb Mon Sep 17 00:00:00 2001
From: Prasad J Pandit <pjp@fedoraproject.org>
Date: Thu, 16 Nov 2017 13:21:55 +0530
Subject: [PATCH] ps2: check PS2Queue pointers in post_load routine
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>
CVE: CVE-2017-16845
Upstream-Status: Backport
Signed-off-by: Hongxu Jia <hongxu.jia@windriver.com>
---
hw/input/ps2.c | 21 +++++++++------------
1 file changed, 9 insertions(+), 12 deletions(-)
diff --git a/hw/input/ps2.c b/hw/input/ps2.c
index f388a23..de171a2 100644
--- a/hw/input/ps2.c
+++ b/hw/input/ps2.c
@@ -1225,24 +1225,21 @@ static void ps2_common_reset(PS2State *s)
static void ps2_common_post_load(PS2State *s)
{
PS2Queue *q = &s->queue;
- int size;
- int i;
- int tmp_data[PS2_QUEUE_SIZE];
+ uint8_t i, size;
+ uint8_t tmp_data[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 */
- if (size > 0) {
- for (i = 0; i < size; i++) {
- /* move the queue elements to the temporary buffer */
- tmp_data[i] = q->data[q->rptr];
- if (++q->rptr == 256) {
- q->rptr = 0;
- }
+ for (i = 0; i < size; i++) {
+ if (q->rptr < 0 || q->rptr >= sizeof(q->data)) {
+ q->rptr = 0;
}
- memcpy(q->data, tmp_data, size);
+ tmp_data[i] = q->data[q->rptr++];
}
+ memcpy(q->data, tmp_data, size);
+
/* reset rptr/wptr/count */
q->rptr = 0;
q->wptr = size;
--
2.7.4
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