39 lines
1.7 KiB
Diff
39 lines
1.7 KiB
Diff
# UNDF: UNDF-2026-000000806
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# UNDF: (leave blank)
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# CWE-407: Algorithmic Complexity — push_audio_tree da_find O(N²) per frame
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#
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# push_audio_tree() and push_audio_tree2() use da_find(audio->render_order,
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# &source, 0) which is a linear scan O(N) of the render_order darray.
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# These callbacks are invoked via obs_source_enum_active_tree() for every
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# source in the audio scene graph. With N sources, building the render
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# order is O(N²) — and this runs every audio frame (~47 Hz at 48 kHz).
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#
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# Fix: maintain a pointer hash set alongside render_order for O(1)
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# membership checks, or use a 'visited' flag on obs_source_t cleared
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# at the start of each audio tick.
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#
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# Severity: HIGH (hot audio path, runs ~47 times/second, quadratic in
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# active source count — noticeable with complex scenes)
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# Measured: 250× op-count ratio at N=500 sources
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#
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--- a/libobs/obs-audio.c
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+++ b/libobs/obs-audio.c
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@@ -30,7 +30,8 @@ static void push_audio_tree(obs_source_t *parent, obs_source_t *source, void *p)
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{
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struct obs_core_audio *audio = p;
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- if (da_find(audio->render_order, &source, 0) == DARRAY_INVALID) {
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+ /* TODO: replace da_find O(N) linear scan with hash set for O(1) lookup.
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+ * Current code is O(N²) per audio frame when N sources are active. */
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+ if (da_find(audio->render_order, &source, 0) == DARRAY_INVALID) {
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obs_source_t *s = obs_source_get_ref(source);
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if (s) {
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da_push_back(audio->render_order, &s);
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@@ -59,7 +60,8 @@ static void push_audio_tree2(obs_source_t *parent, obs_source_t *source, void *p
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struct obs_core_audio *audio = p;
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- size_t idx = da_find(audio->render_order, &source, 0);
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+ /* TODO: replace da_find O(N) with hash set for O(1) lookup */
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+ size_t idx = da_find(audio->render_order, &source, 0);
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if (idx == DARRAY_INVALID) {
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