Add fuzzer for fax codec

Add fuzzer for fax codec

Committed: https://pdfium.googlesource.com/pdfium/+/b1a7134afb4fe5d47ebbc4f728cf97eaa173e9d0

[kcwu, 2016-09-17 13:21:04]

kcwu@chromium.org changed reviewers:
+ tsepez@chromium.org

[kcwu, 2016-09-17 13:23:33]

PTAL, thanks

I don't know how to handle endian in pdfium, so I have GetInteger() locally.

[Tom Sepez, 2016-09-19 16:28:48]

https://codereview.chromium.org/2342203006/diff/1/testing/libfuzzer/pdf_codec...
File testing/libfuzzer/pdf_codec_fax_fuzzer.cc (right):

https://codereview.chromium.org/2342203006/diff/1/testing/libfuzzer/pdf_codec...
testing/libfuzzer/pdf_codec_fax_fuzzer.cc:26: int Columns = std::max(1,
std::min(USHRT_MAX, GetInteger(data + 12)));
Why are we bounding these? the decoder should guard against bad values, no?

[Tom Sepez, 2016-09-19 16:29:32]

On 2016/09/17 13:23:33, kcwu wrote:
> PTAL, thanks
> 
> I don't know how to handle endian in pdfium, so I have GetInteger() locally.
That's fine.

[kcwu, 2016-09-19 16:38:48]

https://codereview.chromium.org/2342203006/diff/1/testing/libfuzzer/pdf_codec...
File testing/libfuzzer/pdf_codec_fax_fuzzer.cc (right):

https://codereview.chromium.org/2342203006/diff/1/testing/libfuzzer/pdf_codec...
testing/libfuzzer/pdf_codec_fax_fuzzer.cc:26: int Columns = std::max(1,
std::min(USHRT_MAX, GetInteger(data + 12)));
On 2016/09/19 16:28:48, Tom Sepez wrote:
> Why are we bounding these? the decoder should guard against bad values, no?

I'm not sure. I just follow the only existing caller.
https://cs.chromium.org/chromium/src/third_party/pdfium/core/fpdfapi/fpdf_par...

[Tom Sepez, 2016-09-19 16:41:25]

Ok, can we see what happens if we remove them?  We might discover ways to make
the API more robust ... otherwise this is fine.

[kcwu, 2016-09-19 16:58:34]

On 2016/09/19 16:41:25, Tom Sepez wrote:
> Ok, can we see what happens if we remove them?  We might discover ways to make
> the API more robust ... otherwise this is fine.

It still works well.
CL revised, PTAL.

[Tom Sepez, 2016-09-19 17:45:29]

lgtm

[kcwu, 2016-09-19 17:52:29]

The CQ bit was checked by kcwu@chromium.org

[commit-bot: I haz the power, 2016-09-19 17:52:34]

CQ is trying da patch. Follow status at
 
https://chromium-cq-status.appspot.com/v2/patch-status/codereview.chromium.or...

[commit-bot: I haz the power, 2016-09-19 18:06:34]

Description was changed from

==========
Add fuzzer for fax codec
==========

to

==========
Add fuzzer for fax codec

Committed:
https://pdfium.googlesource.com/pdfium/+/b1a7134afb4fe5d47ebbc4f728cf97eaa173...
==========

[commit-bot: I haz the power, 2016-09-19 18:06:35]

Committed patchset #2 (id:20001) as
https://pdfium.googlesource.com/pdfium/+/b1a7134afb4fe5d47ebbc4f728cf97eaa173...