Commit 6c6a9781 authored by Alexander Voronov's avatar Alexander Voronov
Browse files

Prevent decoder from using uninitialized entropy context.

If decoding starts with intra-only frame, there is a possibility
of using uninitialized entropy context, what leads to undefined
behavior.

Change-Id: Icbb64b5b1bd1e5de2a4bfa2884e56bc0a20840af
parent 26a07212
...@@ -453,6 +453,7 @@ void vp9_setup_past_independence(VP9_COMMON *cm) { ...@@ -453,6 +453,7 @@ void vp9_setup_past_independence(VP9_COMMON *cm) {
vp9_default_coef_probs(cm); vp9_default_coef_probs(cm);
vp9_init_mode_probs(cm->fc); vp9_init_mode_probs(cm->fc);
vp9_init_mv_probs(cm); vp9_init_mv_probs(cm);
cm->fc->initialized = 1;
if (cm->frame_type == KEY_FRAME || if (cm->frame_type == KEY_FRAME ||
cm->error_resilient_mode || cm->reset_frame_context == 3) { cm->error_resilient_mode || cm->reset_frame_context == 3) {
......
...@@ -50,6 +50,7 @@ typedef struct frame_contexts { ...@@ -50,6 +50,7 @@ typedef struct frame_contexts {
struct tx_probs tx_probs; struct tx_probs tx_probs;
vp9_prob skip_probs[SKIP_CONTEXTS]; vp9_prob skip_probs[SKIP_CONTEXTS];
nmv_context nmvc; nmv_context nmvc;
int initialized;
} FRAME_CONTEXT; } FRAME_CONTEXT;
typedef struct { typedef struct {
......
...@@ -1558,6 +1558,10 @@ void vp9_decode_frame(VP9Decoder *pbi, ...@@ -1558,6 +1558,10 @@ void vp9_decode_frame(VP9Decoder *pbi,
vp9_setup_block_planes(xd, cm->subsampling_x, cm->subsampling_y); vp9_setup_block_planes(xd, cm->subsampling_x, cm->subsampling_y);
*cm->fc = cm->frame_contexts[cm->frame_context_idx]; *cm->fc = cm->frame_contexts[cm->frame_context_idx];
if (!cm->fc->initialized)
vpx_internal_error(&cm->error, VPX_CODEC_CORRUPT_FRAME,
"Uninitialized entropy context.");
vp9_zero(cm->counts); vp9_zero(cm->counts);
vp9_zero(xd->dqcoeff); vp9_zero(xd->dqcoeff);
......
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