[PATCH v11 0/5] Improve code in zcrypt msg type 6 handling

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

Rework the limit and overflow checks in the both functions
xcrb_msg_to_type6_ep11cprb_msgx() and xcrb_msg_to_type6cprb_msgx().
And more ... all related to the length checks done in these both
functions.

Changelog:

v1: initial version, one patch dealing with overflow checks around
    the use of the CEIL4 macro in zcrypt_msgtype6.c
v2: Sashiko found a regression: The check
      if (ap_msg->len > ap_msg->bufsize)
    was missing in the rework. Added again this important check.
v3: - Split into two patches  - one for CCA one for EP11
    - rework upper limit/overflow check 
    - add lower limit check
v4: - tried to address all the remaining complains from sashiko.
v5: - Yea, sashiko still found out that the min req size needs
      to take the minimal payload header into account. Fixed.
v6: - And finally add padding zeros when there is a gap between
      user space provided message size and rounded message size
      in kernel.
v7: - As requested by Holger, the padding code is now an own patch.
    - As the length checks are now so strict the allocation in the
      both misc files needed adaption to correctly allocate 4 byte
      rounded up message buffers.
    - The EP11 length check has been found to be a mess. The payload
      is asn1 encoded and now the length parses parts of this payload
      to extract the needed fields (function value).
    - Furthermore another function zcrypt_msgtype6_send_ep11_cprb()
      also needed to be adjusted to parse the asn1 payload to patch
      the domain value into the payload.
v8: - Sashiko found out that the cprb free with memory scrub also
      needs adaption when the allocation rounds up to a 4 byte
      boundary. So fixed just this in the first patch of the series. 
v9: - hunk for cprb free with 4 byte boundary for EP11 was missing.
    - use of put_unaligned_be16/32 instead of direct cast and store.
v10: - make the asn1 parsing bullet proof. Sashiko found that under
       some circumstances there could have been an access behind the
       actual payload.
     - Added Cc and Fixes tags.
v11: - Added some Reviewed-by from Holger.
     - Fixed the wrong limit checks with offs >= pld_len mentioned
       by Sashiko.

Harald Freudenberger (5):
  s390/zcrypt: Fix CPRB memory allocation in zcrypt misc code
  s390/zcrypt: Improve CCA CPRB length and overflow checks
  s390/zcrypt: Improve EP11 CPRB length and overflow checks
  s390/zcrypt: Improve EP11 CPRB domain handling with ASN.1 parsing
  s390/zcrypt: Pad trailing CCA or EP11 message with zeros

 drivers/s390/crypto/zcrypt_ccamisc.c  |  20 +-
 drivers/s390/crypto/zcrypt_ep11misc.c |  16 +-
 drivers/s390/crypto/zcrypt_msgtype6.c | 366 ++++++++++++++++++--------
 3 files changed, 278 insertions(+), 124 deletions(-)

--
2.43.0