ffmpeg | branch: master | Andreas Rheinhardt <[email protected]> | Fri Oct 8 08:55:56 2021 +0200| [5e1dac380bea627e5b7751e07bdabc0f4ee139c2] | committer: Andreas Rheinhardt
avfilter/avfiltergraph: Fix use-after-free when inserting auto-converter When inserting an auto-resampler, it may be that the configuration of the filters that the auto-resampler is supposed to connect is already partially merged, i.e. converter->inputs[0].incfg.foo and converter->outputs[0].outcfg.foo (where foo is one of formats, samplerates, channel_layouts) can coincide. Therefore merging the converter filter's input link might modify the outcfg of the converter' outlink. Yet the current code in avfiltergraph.c used pointers from before merging the inlink for merging the outlink, leading to a use-after-free in command lines like: $ ffmpeg -f lavfi -i anullsrc=cl=stereo -lavfi channelsplit,axcorrelate -f null - Fix this by not using outdated values when merging the outlink. This is a regression since 85a6404d7e6c759ddf71d6374812d7ff719728ec. Found-by: Paul B Mahol <[email protected]> Reviewed-by: Paul B Mahol <[email protected]> Signed-off-by: Andreas Rheinhardt <[email protected]> > http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=5e1dac380bea627e5b7751e07bdabc0f4ee139c2 --- libavfilter/avfiltergraph.c | 11 +++++------ 1 file changed, 5 insertions(+), 6 deletions(-) diff --git a/libavfilter/avfiltergraph.c b/libavfilter/avfiltergraph.c index e536abef8e..b8b432e98b 100644 --- a/libavfilter/avfiltergraph.c +++ b/libavfilter/avfiltergraph.c @@ -520,14 +520,13 @@ static int query_formats(AVFilterGraph *graph, void *log_ctx) av_assert0(outlink-> incfg.channel_layouts->refcount > 0); av_assert0(outlink->outcfg.channel_layouts->refcount > 0); } +#define MERGE(merger, link) \ + ((merger)->merge(FF_FIELD_AT(void *, (merger)->offset, (link)->incfg), \ + FF_FIELD_AT(void *, (merger)->offset, (link)->outcfg))) for (neg_step = 0; neg_step < neg->nb_mergers; neg_step++) { const AVFilterFormatsMerger *m = &neg->mergers[neg_step]; - void *ia = FF_FIELD_AT(void *, m->offset, inlink->incfg); - void *ib = FF_FIELD_AT(void *, m->offset, inlink->outcfg); - void *oa = FF_FIELD_AT(void *, m->offset, outlink->incfg); - void *ob = FF_FIELD_AT(void *, m->offset, outlink->outcfg); - if ((ret = m->merge(ia, ib)) <= 0 || - (ret = m->merge(oa, ob)) <= 0) { + if ((ret = MERGE(m, inlink)) <= 0 || + (ret = MERGE(m, outlink)) <= 0) { if (ret < 0) return ret; av_log(log_ctx, AV_LOG_ERROR, _______________________________________________ ffmpeg-cvslog mailing list [email protected] https://ffmpeg.org/mailman/listinfo/ffmpeg-cvslog To unsubscribe, visit link above, or email [email protected] with subject "unsubscribe".
