Bug 2406749 (CVE-2025-40031)

Summary: CVE-2025-40031 kernel: tee: fix register_shm_helper()
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security <prodsec-ir-bot>
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OS: Linux   
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Description OSIDB Bzimport 2025-10-28 12:03:28 UTC 
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.
Comment 1 Jon Moroney 2025-10-28 18:46:29 UTC 
Upstream advisory:
https://lore.kernel.org/linux-cve-announce/2025102810-CVE-2025-40031-3ff1@gregkh/T