[FFmpeg-devel] [PATCH] speedhq: make sure the block index is not negative

[Steinar H. Gunderson]

On Tue, Jan 31, 2017 at 01:57:31AM +0100, Andreas Cadhalpun wrote:
>> This sounds like a strangeness in constructing the table, which shouldn't be
>> papered over in the inner loop of the decoder.
> Maybe, I don't know what the contents of the table should be, but the following
> are {-1, 0}: 32, 33, 64, 96, 128

Seemingly they are, indeed.

>> Do you have an actual input where your code makes a difference?
> Yes, without this patch ubsan reports:
> src/libavcodec/speedhq.c:206:13: runtime error: index -1 out of bounds for type 'uint8_t [128]'

Would you mind sharing an input where this actually triggers? None of the
samples I have seem to trigger this, so I suppose it's some sort of fuzzed
input.

/* Steinar */
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