On Fri, May 24, 2024 at 12:15:47PM +0200, Greg Kroah-Hartman wrote:
> Nice, but then why was this commit worded this way? Now we check twice?
> Double safe? Should it be reverted?
double safe's good; turning it into a CVE not so much :(
CVE-2023-52822, CVE-2023-52824 and CVE-2023-52820, originally from the same patch
series, seem to be the exact same case.
CVE-2023-52822:
int vmw_surface_define_ioctl(struct drm_device *dev, void *data,
struct drm_file *file_priv)
{
...
if (num_sizes > DRM_VMW_MAX_SURFACE_FACES * DRM_VMW_MAX_MIP_LEVELS ||
num_sizes == 0)
return -EINVAL;
...
metadata->num_sizes = num_sizes;
metadata->sizes =
memdup_user((struct drm_vmw_size __user *)(unsigned long)
req->size_addr,
sizeof(*metadata->sizes) * metadata->num_sizes);
}
CVE-2023-52824 (here the check is in the immediately preceeding statement, could it
be any more obvious?):
long watch_queue_set_filter(struct pipe_inode_info *pipe,
struct watch_notification_filter __user *_filter)
{
if (filter.nr_filters == 0 ||
filter.nr_filters > 16 ||
filter.__reserved != 0)
return -EINVAL;
tf = memdup_user(_filter->filters, filter.nr_filters * sizeof(*tf));
}
CVE-2023-52820 is a little less obvious to be safe, but I believe it is:
int drm_mode_create_lease_ioctl(struct drm_device *dev,
void *data, struct drm_file *lessor_priv)
{
...
object_ids = memdup_user(u64_to_user_ptr(cl->object_ids),
array_size(object_count, sizeof(__u32)));
array_size() will safely multiply object_count * 4 and return SIZE_MAX on
overflow, making the kmalloc inside memdup_user cleanly fail with -ENOMEM.
> I'll go revoke this, thanks for the review!
could you check and revoke all the above as well?
Thanks,
--
Jiri Bohac <jbohac@xxxxxxx>
SUSE Labs, Prague, Czechia
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