[edk2-devel] [PATCH 0/3] MdePkg, OvmfPkg: rewrite Base64Decode(), clean up call site

Laszlo Ersek lersek at redhat.com
Wed Jul 10 09:20:37 UTC 2019


On 07/02/19 12:28, Laszlo Ersek wrote:
> Repo:   https://github.com/lersek/edk2.git
> Branch: base64_decode_bz1891
> 
> Base64Decode() has a number of issues; see
> 
> - <https://bugzilla.tianocore.org/show_bug.cgi?id=1891>
> 
> - and the mailing list discussion linked from
>   <https://bugzilla.tianocore.org/show_bug.cgi?id=1891#c6>.
> 
> In my opinion, rewriting Base64Decode() from scratch, using a different
> (state machine-based) approach is safer / more robust than attempting to
> identify and patch up individual problems in the current implementation.
> The emphasis of the proposed implementation is to reject invalid input;
> decoding valid input is kind of secondary. (This is the safe approach
> for all parsers that process untrusted input, in my opinion.)
> 
> My understanding is that unit tests for Base64Decode() already exist in
> some repository. While I tested the new implementation through OvmfPkg's
> EnrollDefaultKeys application -- which makes the sole calls to
> Base64Decode() in the open source edk2 tree -- I didn't run a unit test
> suite. Help with that (pointers to the test suite, or actual unit
> testing) would be highly appreciated.
> 
> Cc: Ard Biesheuvel <ard.biesheuvel at linaro.org>
> Cc: Jordan Justen <jordan.l.justen at intel.com>
> Cc: Liming Gao <liming.gao at intel.com>
> Cc: Marvin Häuser <mhaeuser at outlook.de>
> Cc: Michael D Kinney <michael.d.kinney at intel.com>
> Cc: Philippe Mathieu-Daudé <philmd at redhat.com>
> Cc: Zhichao Gao <zhichao.gao at intel.com>
> 
> Thanks
> Laszlo
> 
> Laszlo Ersek (3):
>   MdePkg/BaseLib: re-specify Base64Decode(), and add temporary stub impl
>   MdePkg/BaseLib: rewrite Base64Decode()
>   OvmfPkg/EnrollDefaultKeys: clean up Base64Decode() retval handling
> 
>  MdePkg/Include/Library/BaseLib.h              |  99 ++++-
>  MdePkg/Library/BaseLib/String.c               | 448 +++++++++++++-------
>  OvmfPkg/EnrollDefaultKeys/EnrollDefaultKeys.c |  10 +-
>  3 files changed, 374 insertions(+), 183 deletions(-)
> 

Ping.

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