[Opensc-commits] [OpenSC/OpenSC] c7af08: PIV - read just length of object to get size

[GitHub <no...@gi...>]

  Branch: refs/heads/master
  Home:   https://github.com/OpenSC/OpenSC
  Commit: c7af08c68a5bb3e753b008822e947d52016266c0
      https://github.com/OpenSC/OpenSC/commit/c7af08c68a5bb3e753b008822e947d52016266c0
  Author: Doug Engert <dee...@gm...>
  Date:   2015-05-13 (Wed, 13 May 2015)

  Changed paths:
    M src/libopensc/card-piv.c

  Log Message:
  -----------
  PIV - read just length of object to get size

card-piv.c tries to read the first 8 bytes of an object to get object size
so it can allocate a buffer. It then reads the whole object. apdu.c has changed
over the years, and apdu.c will keep reading as long as the card returns
status of 61 XX  thus apdu.c will read the whole object while discarding
the extra data and returning to the caller only the first part of the data.
This in effect causes a double read of objects.

This patch sets SC_APDU_FLAGS_NO_GET_RESP to tell apdu to stop doing the
extra get-response commands thus avoiding most of the extra overhead.

This in not an optimal patch as it only works with T=1 cards/readers
but the patch is confined to just card-piv.c.
A better patch is in the works.

Fixes #462