From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:37394) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1eFEy7-0005AJ-0U for qemu-devel@nongnu.org; Thu, 16 Nov 2017 02:52:16 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1eFEy3-0005lX-Uf for qemu-devel@nongnu.org; Thu, 16 Nov 2017 02:52:15 -0500 Received: from mx1.redhat.com ([209.132.183.28]:43646) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1eFEy3-0005kd-O3 for qemu-devel@nongnu.org; Thu, 16 Nov 2017 02:52:11 -0500 From: P J P Date: Thu, 16 Nov 2017 13:21:55 +0530 Message-Id: <20171116075155.22378-1-ppandit@redhat.com> Subject: [Qemu-devel] [PATCH v1] ps2: check PS2Queue pointers in post_load routine List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Qemu Developers Cc: Gerd Hoffmann , "Daniel P . Berrange" , Paolo Bonzini , Cyrille Chatras , "Dr . David Alan Gilbert" , 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' 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 --- hw/input/ps2.c | 21 +++++++++------------ 1 file changed, 9 insertions(+), 12 deletions(-) Update: avoid changing field type, add range check on values -> https://lists.gnu.org/archive/html/qemu-devel/2017-11/msg02815.html 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; -- 2.13.6