Red Hat Bugzilla – Bug 1022002
AESNI broken in openssl-1.0.1e-15.el6.x86_64
Last modified: 2014-10-04 12:40:57 EDT
Description of problem:
The new version of openssl shipped in RHEL 6.5 breaks aesni hardware accelleration.
There are two problems, firstly that the engine .so is missing (although I believe this is probably deliberate it should be documented as attempting to specify this engine now results in an error)
The second problem is that the accelleration isn't enabled in core.
This means that on a modern intel CPU, aes-128-cbc speed (as tested by openssl speed -evp aes-128-cbc) drops from around 691902.42k to 22027.95k (1024 keysize) between RHEL 6.4 and RHEL 6.5 - which obviously isn't acceptable.
Disabling the disable-aesni patch (patch number 67) fixes the problem, but as the patch looks like it's there to provide an optional (and disabled by default) way to turn off aesni at build time, it's unclear why this is.
Version-Release number of selected component (if applicable):
Steps to Reproduce:
1. Start with RHEL 6.4. Run openssl speed -evp aes-128-cbc
2. Update to RHEL 6.5
3. Run openssl speed -evp aes-128-cbc again
roughly 30x slowdown
no slowdown at all.
Apologies for the noise - this was actually caused by buggy power management on the test server that only showed up once updated.
It might be worth mentioning in the docs that the external engine for aesni has gone away, and that it no longer needs to be manually enabled, though.
We will document it in the errata text. Reassigning to release notes for further documentation consideration.
The following text has been added in the Technical Notes book as agreed with Tomas:
The external Advanced Encryption Standard (AES) New Instructions (AES-NI) engine is no longer available in openssl; the engine is now built-in and therefore no longer needs to be manually enabled.
Closing; the book is available online: