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.biesheu...@linaro.org>
> Cc: Jordan Justen <jordan.l.jus...@intel.com>
> Cc: Liming Gao <liming....@intel.com>
> Cc: Marvin Häuser <mhaeu...@outlook.de>
> Cc: Michael D Kinney <michael.d.kin...@intel.com>
> Cc: Philippe Mathieu-Daudé <phi...@redhat.com>
> Cc: Zhichao Gao <zhichao....@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(-)
>
Thank you all for the feedback!
* Added a paragraph to the commit message of patch#2, as requested by
Phil, based on the discussion with Marvin:
+ The intent is to only strengthen the checks (sanity and input)
relative to
+ the previous implementation, hence the MAX_ADDRESS checks are
reinstated.
...
+ [ler...@redhat.com: add last para to commit msg per talks w/ Marvin &
Phil]
* Pushed the first two patches in the series as commit range
84a459472075..35e242b698cd; closing
<https://bugzilla.tianocore.org/show_bug.cgi?id=1891>.
* Filed <https://bugzilla.tianocore.org/show_bug.cgi?id=1980> to track
the CCS non-conformance issue, under approach "2a" (i.e.,
incrementally), as agreed upon with Zhichao. Assigned the BZ to
myself; will post a patch soon.
* Split off the last patch in the series to a separate TianoCore BZ,
namely <https://bugzilla.tianocore.org/show_bug.cgi?id=1981>. Assigned
that BZ to myself too.
Thanks,
Laszlo
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