4.19-stable review patch. If anyone has any objections, please let me know.
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From: Matthew Wilcox willy@infradead.org
commit 69ef943dbc14b21987c79f8399ffea08f9a1b446 upstream.
Passing an object_count of sufficient size will make object_count * 4 wrap around to be very small, then a later function will happily iterate off the end of the object_ids array. Using array_size() will saturate at SIZE_MAX, the kmalloc() will fail and we'll return an -ENOMEM to the norty userspace.
Fixes: 62884cd386b8 ("drm: Add four ioctls for managing drm mode object leases [v7]") Signed-off-by: Matthew Wilcox willy@infradead.org Acked-by: Kees Cook keescook@chromium.org Acked-by: Daniel Vetter daniel.vetter@ffwll.ch Cc: stable@vger.kernel.org # v4.15+ Signed-off-by: Dave Airlie airlied@redhat.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- drivers/gpu/drm/drm_lease.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)
--- a/drivers/gpu/drm/drm_lease.c +++ b/drivers/gpu/drm/drm_lease.c @@ -521,7 +521,8 @@ int drm_mode_create_lease_ioctl(struct d
object_count = cl->object_count;
- object_ids = memdup_user(u64_to_user_ptr(cl->object_ids), object_count * sizeof(__u32)); + object_ids = memdup_user(u64_to_user_ptr(cl->object_ids), + array_size(object_count, sizeof(__u32))); if (IS_ERR(object_ids)) return PTR_ERR(object_ids);