On Tue, Dec 07, 2021 at 08:12:53PM +0800, Yy wrote:
>
>
> > 2021年12月7日 下午7:25，Michael Niedermayer <mich...@niedermayer.cc> 写道：
> >
> > On Mon, Dec 06, 2021 at 08:21:42PM +0800, Yu Yang wrote:
> >> If cannot allocate memory, ERROR(ENOMEM) '-12' as a parameter will be
> >> constantly being returned.
> >> When run resample() firstly, negative size param would cause
> >> buffer-overflow and SEGV in swri_rematrix().
> >> When run swri_rematrix() firstly, resample() would not cause error but Err
> >> num as a wrong parameter passing.
> >> Err num should be returned immediately. And remove assert to ensure the
> >> return of the error code.
> >>
> >> coredump info:
> >> #0 0x499517 in posix_memalign (/home/r1/ffmpeg/ffmpeg_4.4.1+0x499517)
> >> #1 0x6c1f0b4 in av_malloc
> >> /home/r1/ffmpeg/ffmpeg-4.4.1/build/src/libavutil/mem.c:86:9
> >> #2 0x6c208fe in av_mallocz
> >> /home/r1/ffmpeg/ffmpeg-4.4.1/build/src/libavutil/mem.c:239:17
> >> #3 0x6c207ad in av_mallocz_array
> >> /home/r1/ffmpeg/ffmpeg-4.4.1/build/src/libavutil/mem.c:195:12
> >> #4 0x654b2e5 in swri_realloc_audio
> >> /home/r1/ffmpeg/ffmpeg-4.4.1/build/src/libswresample/swresample.c:418:14
> >> #5 0x654f9a1 in swr_convert_internal
> >> /home/r1/ffmpeg/ffmpeg-4.4.1/build/src/libswresample/swresample.c:601:17
> >> #6 0x654d2c0 in swr_convert
> >> /home/r1/ffmpeg/ffmpeg-4.4.1/build/src/libswresample/swresample.c:766:19
> >> #7 0x186cf56 in flush_frame
> >> /home/r1/ffmpeg/ffmpeg-4.4.1/build/src/libavfilter/af_aresample.c:251:13
> >> #8 0x186a454 in request_frame
> >> /home/r1/ffmpeg/ffmpeg-4.4.1/build/src/libavfilter/af_aresample.c:288:20
> >> #9 0x787d9c in ff_request_frame_to_filter
> >> /home/r1/ffmpeg/ffmpeg-4.4.1/build/src/libavfilter/avfilter.c:459:15
> >> #10 0x7877f1 in forward_status_change
> >> /home/r1/ffmpeg/ffmpeg-4.4.1/build/src/libavfilter/avfilter.c:1257:19
> >> #11 0x77ed7e in ff_filter_activate_default
> >> /home/r1/ffmpeg/ffmpeg-4.4.1/build/src/libavfilter/avfilter.c:1288:20
> >> #12 0x77e4e1 in ff_filter_activate
> >> /home/r1/ffmpeg/ffmpeg-4.4.1/build/src/libavfilter/avfilter.c:1441:11
> >> #13 0x793b3f in ff_filter_graph_run_once
> >> /home/r1/ffmpeg/ffmpeg-4.4.1/build/src/libavfilter/avfiltergraph.c:1403:12
> >> #14 0x7a7bee in get_frame_internal
> >> /home/r1/ffmpeg/ffmpeg-4.4.1/build/src/libavfilter/buffersink.c:131:19
> >> #15 0x7a7287 in av_buffersink_get_frame_flags
> >> /home/r1/ffmpeg/ffmpeg-4.4.1/build/src/libavfilter/buffersink.c:142:12
> >> #16 0x792888 in avfilter_graph_request_oldest
> >> /home/r1/ffmpeg/ffmpeg-4.4.1/build/src/libavfilter/avfiltergraph.c:1356:17
> >> #17 0x5d07df in transcode_from_filter
> >> /home/r1/ffmpeg/ffmpeg-4.4.1/build/src/fftools/ffmpeg.c:4639:11
> >> #18 0x59e557 in transcode_step
> >> /home/r1/ffmpeg/ffmpeg-4.4.1/build/src/fftools/ffmpeg.c:4729:20
> >> #19 0x593970 in transcode
> >> /home/r1/ffmpeg/ffmpeg-4.4.1/build/src/fftools/ffmpeg.c:4805:15
> >> #20 0x58f7a4 in main
> >> /home/r1/ffmpeg/ffmpeg-4.4.1/build/src/fftools/ffmpeg.c:5010:9
> >> #21 0x7f6fd2dee0b2 in __libc_start_main
> >> /build/glibc-eX1tMB/glibc-2.31/csu/../csu/libc-start.c:308:16
> >>
> >> SUMMARY: AddressSanitizer: negative-size-param
> >> (/home/r1/ffmpeg/ffmpeg_4.4.1+0x497e67) in __asan_memcpy
> >>
> >> Reported-by: TOTE Robot <os...@tsinghua.edu.cn>
> >> Signed-off-by: Yu Yang <young_chel...@163.com>
> >> ---
> >> libswresample/swresample.c | 6 +++++-
> >> 1 file changed, 5 insertions(+), 1 deletion(-)
> >>
> >> diff --git a/libswresample/swresample.c b/libswresample/swresample.c
> >> index c03fe5528f..92ab6a9148 100644
> >> --- a/libswresample/swresample.c
> >> +++ b/libswresample/swresample.c
> >> @@ -644,6 +644,8 @@ static int swr_convert_internal(struct SwrContext *s,
> >> AudioData *out, int out_co
> >> if(s->resample_first){
> >
> >> if(postin != midbuf)
> >> out_count= resample(s, midbuf, out_count, postin, in_count);
> >> + if (out_count < 0)
> >> + return out_count;
> >
> > this doesnt look right
> I could not understand your relpy. Do you mean this bug not exist, or this
> patch not good ?
The patch looks wrong
Do you see the difference between teh 3 pieces of code below:
if(postin != midbuf)
out_count= resample(s, midbuf, out_count, postin, in_count);
if (out_count < 0)
return out_count;
if(postin != midbuf)
out_count= resample(s, midbuf, out_count, postin, in_count);
if (out_count < 0)
return out_count;
if(postin != midbuf) {
out_count= resample(s, midbuf, out_count, postin, in_count);
if (out_count < 0)
return out_count;
}
[...]
--
Michael GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB
Its not that you shouldnt use gotos but rather that you should write
readable code and code with gotos often but not always is less readable
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