From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:36603) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1eEx57-0001UL-IU for qemu-devel@nongnu.org; Wed, 15 Nov 2017 07:46:18 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1eEx54-00041V-8Q for qemu-devel@nongnu.org; Wed, 15 Nov 2017 07:46:17 -0500 Received: from mx1.redhat.com ([209.132.183.28]:52902) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1eEx54-00040v-2e for qemu-devel@nongnu.org; Wed, 15 Nov 2017 07:46:14 -0500 From: P J P Date: Wed, 15 Nov 2017 18:16:02 +0530 Message-Id: <20171115124602.12501-1-ppandit@redhat.com> Subject: [Qemu-devel] [PATCH] ps2: fix PS2Queue counter field type List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Qemu Developers Cc: Gerd Hoffmann , Paolo Bonzini , Cyrille Chatras , Prasad J Pandit From: Prasad J Pandit 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 Signed-off-by: Prasad J Pandit --- 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