[FFmpeg-devel] [PATCH] avcodec/htmlsubtitles: Be a bit more picky on syntax

[wm4]

On Thu, 25 May 2017 19:32:06 +0200
Michael Niedermayer <michael at niedermayer.cc> wrote:

> This reduces the number of strstr() calls per byte
> 
> Fixes timeout
> Fixes: 1817/clusterfuzz-testcase-minimized-5104230530547712
> 
> Found-by: continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg
> Signed-off-by: Michael Niedermayer <michael at niedermayer.cc>
> ---
>  libavcodec/htmlsubtitles.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/libavcodec/htmlsubtitles.c b/libavcodec/htmlsubtitles.c
> index 16295daa0c..e69681f31c 100644
> --- a/libavcodec/htmlsubtitles.c
> +++ b/libavcodec/htmlsubtitles.c
> @@ -92,7 +92,7 @@ int ff_htmlmarkup_to_ass(void *log_ctx, AVBPrint *dst, const char *in)
>          case '<':
>              tag_close = in[1] == '/';
>              len = 0;
> -            if (sscanf(in+tag_close+1, "%127[^>]>%n", buffer, &len) >= 1 && len > 0) {
> +            if (sscanf(in+tag_close+1, "%127[^<>]>%n", buffer, &len) >= 1 && len > 0) {
>                  const char *tagname = buffer;
>                  while (*tagname == ' ')
>                      tagname++;
> @@ -149,7 +149,7 @@ int ff_htmlmarkup_to_ass(void *log_ctx, AVBPrint *dst, const char *in)
>                          }
>                      } else if (tagname[0] && !tagname[1] && strspn(tagname, "bisu") == 1) {
>                          av_bprintf(dst, "{\\%c%d}", tagname[0], !tag_close);
> -                    } else {
> +                    } else if (*tagname) {
>                          unknown = 1;
>                          snprintf(tmp, sizeof(tmp), "</%s>", tagname);
>                      }

Does it change semantics, and how?