| Message ID | 20200809155748.30092-10-andreas.rheinhardt@gmail.com |
|---|---|
| State | Accepted |
| Commit | 44bcd6f74922ba490e680e79eae897b249c29d62 |
| Headers | show |
| Series | [FFmpeg-devel,1/6] avfilter/formats: Remove ff_make_formatu64_list() | expand |
| Context | Check | Description |
|---|---|---|
| andriy/default | pending | |
| andriy/make | success | Make finished |
| andriy/make_fate | success | Make fate finished |
Andreas Rheinhardt (12020-08-09): > The query_formats function of the channelmap filter tries to allocate > a list of channel layouts which on success are attached to more permanent > objects (an AVFilterLink) for storage afterwards. If attaching succeeds, > the link becomes one of the common owners (in this case, the only owner) > of the list. Yet if the list has been successfully attached to the link > and an error happens lateron, the list was manually freed, which is wrong, > because it is owned by its link so that the link's pointer to the list will > become dangling and there will be a double-free/use-after-free when the link > is later cleaned up automatically. > > This commit fixes this by removing the custom freeing code; this will > temporarily add a leaking codepath (if attaching the list fails, the list > will leak), but this will be fixed soon by making sure that an > AVFilterChannelLayouts without owner will be automatically freed when > attaching it to an AVFilterLink fails. > > Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@gmail.com> > --- > libavfilter/af_channelmap.c | 24 +++++++----------------- > 1 file changed, 7 insertions(+), 17 deletions(-) Patches 8-16 LGTM. As a matter of style, I would like it better if the last case was handled the same way as the others rather than using the final return, i.e., instead of: if ((ret = a()) < 0 || (ret = b()) < 0) return ret; return c(); I like better : if ((ret = a()) < 0 || (ret = b()) < 0 || (ret = c()) < 0) return ret; return 0; But it is minor and mostly a matter of taste. Regards,
diff --git a/libavfilter/af_channelmap.c b/libavfilter/af_channelmap.c index 285d76a3ef..1f79f89ce3 100644 --- a/libavfilter/af_channelmap.c +++ b/libavfilter/af_channelmap.c @@ -280,28 +280,18 @@ static av_cold int channelmap_init(AVFilterContext *ctx) static int channelmap_query_formats(AVFilterContext *ctx) { ChannelMapContext *s = ctx->priv; - AVFilterChannelLayouts *layouts; AVFilterChannelLayouts *channel_layouts = NULL; int ret; - layouts = ff_all_channel_counts(); - if (!layouts) { - ret = AVERROR(ENOMEM); - goto fail; - } - if ((ret = ff_add_channel_layout (&channel_layouts, s->output_layout )) < 0 || - (ret = ff_set_common_formats (ctx , ff_planar_sample_fmts() )) < 0 || + if ((ret = ff_set_common_formats (ctx, ff_planar_sample_fmts())) < 0 || (ret = ff_set_common_samplerates (ctx , ff_all_samplerates() )) < 0 || - (ret = ff_channel_layouts_ref (layouts , &ctx->inputs[0]->out_channel_layouts)) < 0 || - (ret = ff_channel_layouts_ref (channel_layouts , &ctx->outputs[0]->in_channel_layouts)) < 0) - goto fail; + (ret = ff_add_channel_layout(&channel_layouts, s->output_layout)) < 0 || + (ret = ff_channel_layouts_ref(channel_layouts, + &ctx->outputs[0]->in_channel_layouts)) < 0) + return ret; - return 0; -fail: - if (layouts) - av_freep(&layouts->channel_layouts); - av_freep(&layouts); - return ret; + return ff_channel_layouts_ref(ff_all_channel_counts(), + &ctx->inputs[0]->out_channel_layouts); } static int channelmap_filter_frame(AVFilterLink *inlink, AVFrame *buf)
The query_formats function of the channelmap filter tries to allocate a list of channel layouts which on success are attached to more permanent objects (an AVFilterLink) for storage afterwards. If attaching succeeds, the link becomes one of the common owners (in this case, the only owner) of the list. Yet if the list has been successfully attached to the link and an error happens lateron, the list was manually freed, which is wrong, because it is owned by its link so that the link's pointer to the list will become dangling and there will be a double-free/use-after-free when the link is later cleaned up automatically. This commit fixes this by removing the custom freeing code; this will temporarily add a leaking codepath (if attaching the list fails, the list will leak), but this will be fixed soon by making sure that an AVFilterChannelLayouts without owner will be automatically freed when attaching it to an AVFilterLink fails. Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@gmail.com> --- libavfilter/af_channelmap.c | 24 +++++++----------------- 1 file changed, 7 insertions(+), 17 deletions(-)