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| author | Marton Balint <cus@passwd.hu> | 2023-03-29 00:01:17 +0200 |
|---|---|---|
| committer | Marton Balint <cus@passwd.hu> | 2023-04-02 21:31:05 +0200 |
| commit | 5f92a192315fc9349e7c9bdc923666f79d5c5e8d (patch) | |
| tree | edf5edd575e0bf3e8da9ca722ed7732b5696d097 /libavformat/assenc.c | |
| parent | 85c62b48e9189d84746009f26a4cff41ad5d4603 (diff) | |
| download | ffmpeg-5f92a192315fc9349e7c9bdc923666f79d5c5e8d.tar.gz | |
avformat/assenc: avoid incorrect copy of null terminator
When writing a subtitle SSA/ASS subtitle file, the AVCodecParameters::extradata
buffer is written directly to the output. In the case where the buffer is
filled from a matroska source file produced by some older versions of
Handbrake, this buffer ends with a null terminating character, which is then
erroneously copied into the middle of the output file. The change here avoids
this problem by treating it as a string rather than a raw buffer. This way it
is agnostic as to whether the source buffer was null terminated or not.
Fixes ticket #10203.
Reported-by: Tim Angus <tim at ngus.net>
Signed-off-by: Marton Balint <cus@passwd.hu>
Diffstat (limited to 'libavformat/assenc.c')
| -rw-r--r-- | libavformat/assenc.c | 3 |
1 files changed, 2 insertions, 1 deletions
diff --git a/libavformat/assenc.c b/libavformat/assenc.c index 85a1e53371..6ecfb04517 100644 --- a/libavformat/assenc.c +++ b/libavformat/assenc.c @@ -70,8 +70,9 @@ static int write_header(AVFormatContext *s) ass->trailer = trailer; } + header_size = av_strnlen(par->extradata, header_size); avio_write(s->pb, par->extradata, header_size); - if (par->extradata[header_size - 1] != '\n') + if (header_size && par->extradata[header_size - 1] != '\n') avio_write(s->pb, "\r\n", 2); ass->ssa_mode = !strstr(par->extradata, "\n[V4+ Styles]"); if (!strstr(par->extradata, "\n[Events]")) |