From 802cbcb73002b92e6ddc8464d39b668a71b78d74 Mon Sep 17 00:00:00 2001 From: Prasad J Pandit 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 Signed-off-by: Prasad J Pandit Message-id: 20171116075155.22378-1-ppandit@redhat.com Signed-off-by: Gerd Hoffmann --- 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 f388a23c8e..de171a28dd 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; -- 2.11.4.GIT