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vmwgfx: integer overflow in vmw_kms_update_layout_ioctl()

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There are two issues in vmw_kms_update_layout_ioctl().  First, the
for loop forgets to index rects and only checks the first element.
Second, there is a potential integer overflow if userspace passes
in a large arg->num_outputs.  The call to kzalloc() would allocate
a small buffer, leading to out-of-bounds read.

Reported-by: Haogang Chen <haogangchen@gmail.com>
Signed-off-by: Xi Wang <xi.wang@gmail.com>
Signed-off-by: Thomas Hellstrom <thellstrom@vmware.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>
This commit is contained in:
Xi Wang 2011-11-28 12:25:43 +01:00 committed by Dave Airlie
parent f3a71df050
commit bab9efc206
1 changed files with 6 additions and 5 deletions
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11
drivers/gpu/drm/vmwgfx/vmwgfx_kms.c
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@ -1809,7 +1809,8 @@ int vmw_kms_update_layout_ioctl(struct drm_device *dev, void *data,
}
rects_size = arg->num_outputs * sizeof(struct drm_vmw_rect);
rects = kzalloc(rects_size, GFP_KERNEL);
rects = kcalloc(arg->num_outputs, sizeof(struct drm_vmw_rect),
GFP_KERNEL);
if (unlikely(!rects)) {
ret = -ENOMEM;
goto out_unlock;
@ -1824,10 +1825,10 @@ int vmw_kms_update_layout_ioctl(struct drm_device *dev, void *data,
}
for (i = 0; i < arg->num_outputs; ++i) {
if (rects->x < 0 ||
rects->y < 0 ||
rects->x + rects->w > mode_config->max_width ||
rects->y + rects->h > mode_config->max_height) {
if (rects[i].x < 0 ||
rects[i].y < 0 ||
rects[i].x + rects[i].w > mode_config->max_width ||
rects[i].y + rects[i].h > mode_config->max_height) {
DRM_ERROR("Invalid GUI layout.\n");
ret = -EINVAL;
goto out_free;