From: Prasad J Pandit <p...@fedoraproject.org> 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 issue. Add check to avoid it.
Reported-by: Cyrille Chatras <cyrille.chat...@orange.com> Signed-off-by: Prasad J Pandit <p...@fedoraproject.org> --- hw/input/ps2.c | 39 ++++++++++++++++++--------------------- 1 file changed, 18 insertions(+), 21 deletions(-) Update: return -1(bad indices) error, instead of correcting values -> https://lists.gnu.org/archive/html/qemu-devel/2017-11/msg02964.html diff --git a/hw/input/ps2.c b/hw/input/ps2.c index f388a23c8e..35392d55fc 100644 --- a/hw/input/ps2.c +++ b/hw/input/ps2.c @@ -1222,32 +1222,37 @@ static void ps2_common_reset(PS2State *s) s->update_irq(s->update_arg, 0); } -static void ps2_common_post_load(PS2State *s) +static int ps2_common_post_load(PS2State *s) { PS2Queue *q = &s->queue; int size; int i; int tmp_data[PS2_QUEUE_SIZE]; + if (q->count < 0 || q->rptr < 0 || q->rptr >= sizeof(q->data)) { + return -1; + } + /* 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; - } + 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); } + memcpy(q->data, tmp_data, size); + /* reset rptr/wptr/count */ q->rptr = 0; q->wptr = size; q->count = size; s->update_irq(s->update_arg, q->count != 0); + + return 0; } static void ps2_kbd_reset(void *opaque) @@ -1346,9 +1351,7 @@ static int ps2_kbd_post_load(void* opaque, int version_id) if (version_id == 2) s->scancode_set=2; - ps2_common_post_load(ps2); - - return 0; + return ps2_common_post_load(ps2); } static int ps2_kbd_pre_save(void *opaque) @@ -1356,9 +1359,7 @@ static int ps2_kbd_pre_save(void *opaque) PS2KbdState *s = (PS2KbdState *)opaque; PS2State *ps2 = &s->common; - ps2_common_post_load(ps2); - - return 0; + return ps2_common_post_load(ps2); } static const VMStateDescription vmstate_ps2_keyboard = { @@ -1386,9 +1387,7 @@ static int ps2_mouse_post_load(void *opaque, int version_id) PS2MouseState *s = (PS2MouseState *)opaque; PS2State *ps2 = &s->common; - ps2_common_post_load(ps2); - - return 0; + return ps2_common_post_load(ps2); } static int ps2_mouse_pre_save(void *opaque) @@ -1396,9 +1395,7 @@ static int ps2_mouse_pre_save(void *opaque) PS2MouseState *s = (PS2MouseState *)opaque; PS2State *ps2 = &s->common; - ps2_common_post_load(ps2); - - return 0; + return ps2_common_post_load(ps2); } static const VMStateDescription vmstate_ps2_mouse = { -- 2.13.6
