REDHAT-BUG-2492269: Medium severity Linux Kernel vulnerability
In the Linux kernel, the following vulnerability has been resolved:
crypto: ccp - copy IV using skcipher ivsize
AFALG rfc3686-ctr-aes-ccp requests pass an 8-byte IV to the driver.
ccpaescomplete() restores AESBLOCKSIZE bytes into the caller's IV buffer while RFC3686 skciphers expose an 8-byte IV, so the restore overruns the provided buffer.
Use cryptoskcipherivsize() to copy only the algorithm's IV length.
Affected Software
Event History
Frequently Asked Questions
Which systems are exposed to this issue?
Systems using the Linux kernel CCP crypto driver with AF_ALG RFC3686 CTR-AES requests are exposed. The vulnerable path is reached when those requests provide the RFC3686 skcipher's 8-byte IV to the driver.
What does successful exploitation require?
An attacker or workload must be able to submit AF_ALG RFC3686 CTR-AES requests that reach the CCP driver. The issue occurs when completion restores 16 bytes of IV data into an 8-byte caller-provided IV buffer.
How can the issue be mitigated if an updated kernel cannot be installed immediately?
Avoid using AF_ALG RFC3686 CTR-AES requests through the CCP driver until the kernel fix is available. The provided fix changes IV restoration to use the skcipher algorithm's actual IV size rather than AES_BLOCK_SIZE.