Re: [FFmpeg-devel] [PATCH] 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`.
mezhue...@ispras.ru: > From: headshog > > 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 ___ ffmpeg-devel mailing list ffmpeg-devel@ffmpeg.org https://ffmpeg.org/mailman/listinfo/ffmpeg-devel To unsubscribe, visit link above, or email ffmpeg-devel-requ...@ffmpeg.org with subject "unsubscribe".
Re: [FFmpeg-devel] [PATCH] 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`.
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-requ...@ffmpeg.org with subject "unsubscribe". Maybe then a checker for valid sample_rate value should be added to svs_read_header function? ___ ffmpeg-devel mailing list ffmpeg-devel@ffmpeg.org https://ffmpeg.org/mailman/listinfo/ffmpeg-devel To unsubscribe, visit link above, or email ffmpeg-devel-requ...@ffmpeg.org with subject "unsubscribe".
Re: [FFmpeg-devel] [PATCH] 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`.
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-requ...@ffmpeg.org with subject "unsubscribe".
[FFmpeg-devel] [PATCH] 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`.
From: headshog
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(-)
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
--
2.25.1
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