CVE-2026-80545

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

s390/zcrypt: Improve EP11 CPRB length and overflow checks

The xcrbmsgtotype6ep11cprbmsgx() function lacks proper input validation, creating security vulnerabilities: 1. Missing minimum size validation: The ep11cprb structure and subsequent payload fields (pldtag, pldlenfmt) are copied from userspace without verifying sufficient buffer length. 2. Arithmetic overflow in length calculations: CEIL4 alignment could overflow, bypassing size checks and enabling buffer overflows. 3. The payload is asn1 encoded but the function just uses a simple c struct overlay to access some fields of the payload.

Fix by using sizet for length calculations, adding U32MAX boundary checks after alignment, and validating minimum request size and minimum reply size before copying from userspace. Do a very simple asn1 parsing of the payload up to the function value field.