CVE-2026-31719

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

crypto: krb5enc - fix async decrypt skipping hash verification

krb5enc_dispatch_decrypt() sets req->base.complete as the skcipher

callback, which is the caller's own completion handler. When the

skcipher completes asynchronously, this signals "done" to the caller

without executing krb5enc_dispatch_decrypt_hash(), completely bypassing

the integrity verification (hash check).

Compare with the encrypt path which correctly uses

krb5enc_encrypt_done as an intermediate callback to chain into the

hash computation on async completion.

Fix by adding krb5enc_decrypt_done as an intermediate callback that

chains into krb5enc_dispatch_decrypt_hash() upon async skcipher

completion, matching the encrypt path's callback pattern.

Also fix EBUSY/EINPROGRESS handling throughout: remove

krb5enc_request_complete() which incorrectly swallowed EINPROGRESS

notifications that must be passed up to callers waiting on backlogged

requests, and add missing EBUSY checks in krb5enc_encrypt_ahash_done

for the dispatch_encrypt return value.

Unset MAY_BACKLOG on the async completion path so the user won't

see back-to-back EINPROGRESS notifications.