[PATCH v4 0/1] Improve zcrypt reply message verification checks

[Harald Freudenberger <freude@linux.ibm.com>]

Add or improve checks related to buffer sizes and reply sizes to the
handling of replies from the crypto cards for CCA and EP11 (AP message
type 6) messages. The verification code related to reply field length
was not designed well and thus firmware deficiencies could lead to
unexpected behavior in the zcrypt device driver. Thus improve the code
to more closely inspect especially length fields at message replies.

Changelog:
v1 - initial patch
v2 - fixed typo in header check_for_overflow -> check_add_overflow.
v3 - rephrased and smoothed subject and text of the patch. It is now
     "s390/zcrypt: Improve zcrypt reply message verification checks"
     and the text does not talk about malicious cards any more.
     Updated Reviewed-by tags
v4 - As sashiko clearly states the addition of two 32 bit values can
     mathematically never overflow a 64 bit value and thus the
     check_add_overflow() was total overkill - removed.

Harald Freudenberger (1):
  s390/zcrypt: Improve zcrypt reply message verification checks

 drivers/s390/crypto/zcrypt_msgtype6.c | 11 +++++++++--
 1 file changed, 9 insertions(+), 2 deletions(-)

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2.43.0