CVE-2026-97589: s390/crypto: Fix wrong return code to engine in asynch callbacks
In the Linux kernel, the following vulnerability has been resolved:
s390/crypto: Fix wrong return code to engine in asynch callbacks
When cryptofinalizehashrequest() or cryptofinalizeskcipherrequest() explicitly completes a request, the doonerequest callback must return 0 to indicate successful handling. Returning a negative error code causes the crypto engine to assume the driver failed to take ownership and triggers a second completion via cryptorequestcomplete(), resulting in a double completion. This pattern occurs in paess390.c 4 times and once in phmacs390.c.
Fixed in phmacdoonerequest() and all four paes doonerequest callbacks (ecb, cbc, ctr, xts) by returning 0 after explicit finalization instead of propagating the error code.
Affected Software
Event History
Frequently Asked Questions
Which systems are affected by this issue?
The affected code is in the Linux kernel s390 crypto drivers, specifically PAES ECB, CBC, CTR, and XTS request callbacks and the PHMAC request callback. Systems that do not use these s390 crypto driver paths are not described as affected by the provided information.
What condition triggers the double completion?
It occurs when crypto_finalize_hash_request() or crypto_finalize_skcipher_request() explicitly completes a request but the do_one_request callback returns a negative error code. The crypto engine then treats the request as not having been handled and calls crypto_request_complete() again.
What is the relevant remediation?
Apply the kernel fix that changes phmac_do_one_request() and the four PAES do_one_request callbacks to return 0 after explicitly finalizing a request. This tells the crypto engine that the callback successfully handled request completion.