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authorXi Wang <xi.wang@gmail.com>2011-11-28 12:25:43 +0100
committerDave Airlie <airlied@redhat.com>2011-12-02 10:49:41 +0000
commitbab9efc206ba89766c53a9042eb771e87e68c42b (patch)
tree7413fe6517587d631fca96960ec806d5e8b7e61a /drivers/gpu
parentf3a71df05082c84d1408129084736c5f742a6165 (diff)
vmwgfx: integer overflow in vmw_kms_update_layout_ioctl()
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>
Diffstat (limited to 'drivers/gpu')
-rw-r--r--drivers/gpu/drm/vmwgfx/vmwgfx_kms.c11
1 files changed, 6 insertions, 5 deletions
diff --git a/drivers/gpu/drm/vmwgfx/vmwgfx_kms.c b/drivers/gpu/drm/vmwgfx/vmwgfx_kms.c
index 880e285d7578..37d40545ed77 100644
--- a/drivers/gpu/drm/vmwgfx/vmwgfx_kms.c
+++ b/drivers/gpu/drm/vmwgfx/vmwgfx_kms.c
@@ -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;