| Message ID | 20230920121803.3456113-1-mezhuevtp@ispras.ru |
|---|---|
| State | New |
| Headers | show |
| Series | [FFmpeg-devel] Hi! We've been fuzzing `ffmpeg` with [sydr-fuzz](https://github.com/ispras/oss-sydr-fuzz) security predicates and we found numeric truncation error in `svs.c:57`. | expand |
| Context | Check | Description |
|---|---|---|
| andriy/commit_msg_x86 | warning | The first line of the commit message must start with a context terminated by a colon and a space, for example "lavu/opt: " or "doc: ". |
| andriy/make_x86 | fail | Make failed |
Unacceptable code changes as that Breaks ABI/API.
On 2023-09-20 15:29, Paul B Mahol wrote: > Unacceptable code changes as that Breaks ABI/API. > _______________________________________________ > ffmpeg-devel mailing list > ffmpeg-devel@ffmpeg.org > https://ffmpeg.org/mailman/listinfo/ffmpeg-devel > > To unsubscribe, visit link above, or email > ffmpeg-devel-request@ffmpeg.org with subject "unsubscribe". Maybe then a checker for valid sample_rate value should be added to svs_read_header function?
mezhuevtp@ispras.ru: > From: headshog <craaaaaachind@gmail.com> > > In function `svs_read_header` on line 57 field `st->codecpar->sample_rate` has type `int`, the type of return value in `av_rescale_rnd` function is `uint64_t`, so the numeric truncation may occur here. Then value of `st->codecpar->sample_rate` is passed to `avpriv_set_pts_info` function parameter `unsgined int pts_den`. In this function `pts_den` is used only in passing its value to parameter `int64_t den` in function `av_reduce`. So we suggest to change the type of field `sample_rate` to `int64_t` and to change the type of `pts_den` to `uint64_t` in `avpriv_set_pts_info` function. The other way to solve this is to add a checker for `sample_rate` valid value. > > - OS: ubuntu 20.04 > - commit: f225f8d7464569c7b917015c26ad30a37a5fbbe2 > > ``` > libavformat/svs.c:57:36: runtime error: implicit conversion from type 'int64_t' (aka 'long') of value 6321554672 (64-bit, signed) to type 'int' changed the value to 2026587376 (32-bit, signed) > SUMMARY: UndefinedBehaviorSanitizer: undefined-behavior libavformat/svs.c:57:36 Truncation via implicit conversions is not undefined behavior (but it may be a bug). - Andreas
diff --git a/libavcodec/codec_par.h b/libavcodec/codec_par.h index add90fdb1e..2bbb7ba4e7 100644 --- a/libavcodec/codec_par.h +++ b/libavcodec/codec_par.h @@ -175,7 +175,7 @@ typedef struct AVCodecParameters { /** * Audio only. The number of audio samples per second. */ - int sample_rate; + int64_t sample_rate; /** * Audio only. The number of bytes per coded audio frame, required by some * formats. diff --git a/libavformat/internal.h b/libavformat/internal.h index 901a8b51c6..6e1fce41aa 100644 --- a/libavformat/internal.h +++ b/libavformat/internal.h @@ -584,7 +584,7 @@ const struct AVCodec *ff_find_decoder(AVFormatContext *s, const AVStream *st, * @param pts_den time base denominator */ void avpriv_set_pts_info(AVStream *st, int pts_wrap_bits, - unsigned int pts_num, unsigned int pts_den); + unsigned int pts_num, uint64_t pts_den); /** * Set the timebase for each stream from the corresponding codec timebase and
From: headshog <craaaaaachind@gmail.com> In function `svs_read_header` on line 57 field `st->codecpar->sample_rate` has type `int`, the type of return value in `av_rescale_rnd` function is `uint64_t`, so the numeric truncation may occur here. Then value of `st->codecpar->sample_rate` is passed to `avpriv_set_pts_info` function parameter `unsgined int pts_den`. In this function `pts_den` is used only in passing its value to parameter `int64_t den` in function `av_reduce`. So we suggest to change the type of field `sample_rate` to `int64_t` and to change the type of `pts_den` to `uint64_t` in `avpriv_set_pts_info` function. The other way to solve this is to add a checker for `sample_rate` valid value. - OS: ubuntu 20.04 - commit: f225f8d7464569c7b917015c26ad30a37a5fbbe2 ``` libavformat/svs.c:57:36: runtime error: implicit conversion from type 'int64_t' (aka 'long') of value 6321554672 (64-bit, signed) to type 'int' changed the value to 2026587376 (32-bit, signed) SUMMARY: UndefinedBehaviorSanitizer: undefined-behavior libavformat/svs.c:57:36 ``` --- libavcodec/codec_par.h | 2 +- libavformat/internal.h | 2 +- 2 files changed, 2 insertions(+), 2 deletions(-)