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[Qemu-devel] [PATCH] ps2: fix PS2Queue counter field type
From: |
P J P |
Subject: |
[Qemu-devel] [PATCH] ps2: fix PS2Queue counter field type |
Date: |
Wed, 15 Nov 2017 18:16:02 +0530 |
From: Prasad J Pandit <address@hidden>
During Qemu guest migration, a destination process invokes ps2
post_load function. In that, if 'rptr' and 'count' fields were
tampered, it could lead to OOB access or infinite loop issues.
Change their type to 'uint8_t' so they remain within bounds.
Reported-by: Cyrille Chatras <address@hidden>
Signed-off-by: Prasad J Pandit <address@hidden>
---
hw/input/ps2.c | 26 ++++++++++----------------
1 file changed, 10 insertions(+), 16 deletions(-)
diff --git a/hw/input/ps2.c b/hw/input/ps2.c
index f388a23c8e..ce4b167084 100644
--- a/hw/input/ps2.c
+++ b/hw/input/ps2.c
@@ -90,7 +90,7 @@ typedef struct {
/* Keep the data array 256 bytes long, which compatibility
with older qemu versions. */
uint8_t data[256];
- int rptr, wptr, count;
+ uint8_t rptr, wptr, count;
} PS2Queue;
struct PS2State {
@@ -1225,24 +1225,18 @@ 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;
/* 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;
- }
- }
- memcpy(q->data, tmp_data, size);
+ for (i = 0; i < size; i++) {
+ tmp_data[i] = q->data[q->rptr++];
}
+ memcpy(q->data, tmp_data, size);
+
/* reset rptr/wptr/count */
q->rptr = 0;
q->wptr = size;
@@ -1286,9 +1280,9 @@ static const VMStateDescription vmstate_ps2_common = {
.minimum_version_id = 2,
.fields = (VMStateField[]) {
VMSTATE_INT32(write_cmd, PS2State),
- VMSTATE_INT32(queue.rptr, PS2State),
- VMSTATE_INT32(queue.wptr, PS2State),
- VMSTATE_INT32(queue.count, PS2State),
+ VMSTATE_UINT8(queue.rptr, PS2State),
+ VMSTATE_UINT8(queue.wptr, PS2State),
+ VMSTATE_UINT8(queue.count, PS2State),
VMSTATE_BUFFER(queue.data, PS2State),
VMSTATE_END_OF_LIST()
}
--
2.13.6
- [Qemu-devel] [PATCH] ps2: fix PS2Queue counter field type,
P J P <=