CVE-2026-80546

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

s390/zcrypt: Improve CCA CPRB length and overflow checks

The xcrbmsgtotype6cprbmsgx() function lacks proper input validation, creating security vulnerabilities: 1. Integer overflow after CEIL4 alignment: Signed int variables could overflow during 4-byte boundary alignment, causing undersized buffer allocations or incorrect bounds checking. 2. Missing minimum size validation: The CPRBX structure is copied from userspace without verifying sufficient buffer length. Undersized buffers cause uninitialized memory access when reading structure fields like cprbx.cprb_len and cprbx.domain. 3. Arithmetic overflow in sum calculations: Adding control block and data block sizes could overflow, bypassing size checks and enabling buffer overflows.

Fix by using sizet for length calculations, adding U32MAX boundary checks after alignment, validating minimum control block size before copying from userspace, and detecting sum calculation overflows.