[tor-bugs] #15503 [Tor]: VIA PadLock suupport does not work.

Tor Bug Tracker & Wiki blackhole at torproject.org
Mon May 4 13:10:01 UTC 2015


#15503: VIA PadLock suupport does not work.
---------------------------+--------------------------------
     Reporter:  toyboy     |      Owner:
         Type:  defect     |     Status:  closed
     Priority:  normal     |  Milestone:  Tor: 0.2.???
    Component:  Tor        |    Version:  Tor: unspecified
   Resolution:  not a bug  |   Keywords:  VIA PadLock, lorax
Actual Points:             |  Parent ID:
       Points:             |
---------------------------+--------------------------------
Changes (by yawning):

 * status:  new => closed
 * resolution:   => not a bug


Comment:

 Looked at this a bit more, since we probably should(?) use EVP for the
 non-one-shot hash calls.  The fact ancient VIA processors don't have an
 easy way to get partial hashes ends up being a moot point because OpenSSL
 does not support Padlock's SHA acceleration at all.

 There is partial code for it in master, but it is not wired into the EVP
 interface.  I'm not sure if there's a easy way to implement
 "EVP_MD_CTX_copy_ex()` on the problematic old steppings, but that's the
 OpenSSL developer's problem and not mine.

 In summary:
  * The SSE implementation of AES is used because OpenSSL does not expose
 CTR acceleration for PadLock in non-master.
  * None of the SHA calls are offloaded because OpenSSL does not expose SHA
 acceleration for PadLock at all, and tor doesn't use the EVP interface so
 even if it existed, it wouldn't be used.

 I'll file a separate ticket regarding using EVP for hashing, but that's
 really a separate issue to "OpenSSL's support for PadLock is lacking",
 which is not a tor bug.

--
Ticket URL: <https://trac.torproject.org/projects/tor/ticket/15503#comment:5>
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