[FFmpeg-devel] [PATCH 1/8] ffmdec: initialize f_cprv, f_stvi and f_stau

Andreas Cadhalpun andreas.cadhalpun at googlemail.com
Mon Mar 9 12:41:54 CET 2015

On 09.03.2015 10:53, Lukasz Marek wrote:
> In fact this is a bit wrong. COMM is guaranteed unless malformed file is
> parsed. These variables are dedicated to detect doubled sections. This
> patch allows them to occur twice in that case. So they should be
> initialized to 0.

This patch doesn't change anything for valid files, it only prevents 
crashes with malformed files.

For valid files, these variables are initialized to -1, then set to 0 in 
the COMM part of the switch.

For invalid files, if another section comes before COMM, the counter is 
-1, thus e.g. 'if (f_stvi++)' is true and AVERROR(EINVAL) is returned.

If they were initialized to 0, the check wouldn't trigger for malformed 
files, leading to crashes, because codec is not set.

Best regards,

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