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Commit af40322e authored by Harald Freudenberger's avatar Harald Freudenberger Committed by Alexander Gordeev
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s390/zcrypt: do not retry administrative requests



All kind of administrative requests should not been retried. Some card
firmware detects this and assumes a replay attack. This patch checks
on failure if the low level functions indicate a retry (EAGAIN) and
checks for the ADMIN flag set on the request message.  If this both
are true, the response code for this message is changed to EIO to make
sure the zcrypt API layer does not attempt to retry the request. As of
now the ADMIN flag is set for a request message when
- for EP11 the field 'flags' of the EP11 CPRB struct has the leftmost
  bit set.
- for CCA when the CPRB minor version is 'T3', 'T5', 'T6' or 'T7'.

Please note that the do-not-retry only applies to a request
which has been sent to the card (= has been successfully enqueued) but
the reply indicates some kind of failure and by default it would be
replied. It is totally fine to retry a request if a previous attempt
to enqueue the msg into the firmware queue had some kind of failure
and thus the card has never seen this request.

Reported-by: default avatarFrank Uhlig <Frank.Uhlig1@ibm.com>
Signed-off-by: default avatarHarald Freudenberger <freude@linux.ibm.com>
Reviewed-by: default avatarHolger Dengler <dengler@linux.ibm.com>
Cc: stable@vger.kernel.org
Signed-off-by: default avatarAlexander Gordeev <agordeev@linux.ibm.com>
parent 0fdcc88b
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