CVE-2025-40031

In the Linux kernel, the following vulnerability has been resolved:

tee: fix register_shm_helper()

In register_shm_helper(), fix incorrect error handling for a call to

iov_iter_extract_pages(). A case is missing for when

iov_iter_extract_pages() only got some pages and return a number larger

than 0, but not the requested amount.

This fixes a possible NULL pointer dereference following a bad input from

ioctl(TEE_IOC_SHM_REGISTER) where parts of the buffer isn't mapped.