[FFmpeg-devel] [PATCH 4/5] Check for huffman tree building error in vp6 decoder.

[fenrir at elivagar.org]

From: Laurent Aimar <fenrir at videolan.org>

---
 libavcodec/vp5.c  |    3 ++-
 libavcodec/vp56.c |    4 +++-
 libavcodec/vp56.h |    2 +-
 libavcodec/vp6.c  |   20 ++++++++++++--------
 4 files changed, 18 insertions(+), 11 deletions(-)

diff --git a/libavcodec/vp5.c b/libavcodec/vp5.c
index 7743a48..a1a38b0 100644
--- a/libavcodec/vp5.c
+++ b/libavcodec/vp5.c
@@ -118,7 +118,7 @@ static void vp5_parse_vector_models(VP56Context *s)
                 model->vector_pdv[comp][node] = vp56_rac_gets_nn(c, 7);
 }
 
-static void vp5_parse_coeff_models(VP56Context *s)
+static int vp5_parse_coeff_models(VP56Context *s)
 {
     VP56RangeCoder *c = &s->c;
     VP56Model *model = s->modelp;
@@ -162,6 +162,7 @@ static void vp5_parse_coeff_models(VP56Context *s)
                 for (ctx=0; ctx<6; ctx++)
                     for (node=0; node<5; node++)
                         model->coeff_acct[pt][ct][cg][ctx][node] = av_clip(((model->coeff_ract[pt][ct][cg][node] * vp5_ract_lc[ct][cg][node][ctx][0] + 128) >> 8) + vp5_ract_lc[ct][cg][node][ctx][1], 1, 254);
+    return 0;
 }
 
 static void vp5_parse_coeff(VP56Context *s)
diff --git a/libavcodec/vp56.c b/libavcodec/vp56.c
index 530b890..e18c59e 100644
--- a/libavcodec/vp56.c
+++ b/libavcodec/vp56.c
@@ -541,7 +541,8 @@ int ff_vp56_decode_frame(AVCodecContext *avctx, void *data, int *data_size,
             s->mb_type = VP56_MB_INTER_NOVEC_PF;
         }
 
-        s->parse_coeff_models(s);
+        if (s->parse_coeff_models(s))
+            goto next;
 
         memset(s->prev_dc, 0, sizeof(s->prev_dc));
         s->prev_dc[1][VP56_FRAME_CURRENT] = 128;
@@ -605,6 +606,7 @@ int ff_vp56_decode_frame(AVCodecContext *avctx, void *data, int *data_size,
             }
         }
 
+    next:
         if (p->key_frame || golden_frame) {
             if (s->framep[VP56_FRAME_GOLDEN]->data[0] &&
                 s->framep[VP56_FRAME_GOLDEN] != s->framep[VP56_FRAME_GOLDEN2])
diff --git a/libavcodec/vp56.h b/libavcodec/vp56.h
index 8bb7251..ceb516d 100644
--- a/libavcodec/vp56.h
+++ b/libavcodec/vp56.h
@@ -48,7 +48,7 @@ typedef void (*VP56Filter)(VP56Context *s, uint8_t *dst, uint8_t *src,
 typedef void (*VP56ParseCoeff)(VP56Context *s);
 typedef void (*VP56DefaultModelsInit)(VP56Context *s);
 typedef void (*VP56ParseVectorModels)(VP56Context *s);
-typedef void (*VP56ParseCoeffModels)(VP56Context *s);
+typedef int  (*VP56ParseCoeffModels)(VP56Context *s);
 typedef int  (*VP56ParseHeader)(VP56Context *s, const uint8_t *buf,
                                 int buf_size, int *golden_frame);
 
diff --git a/libavcodec/vp6.c b/libavcodec/vp6.c
index 657a5da..6928a91 100644
--- a/libavcodec/vp6.c
+++ b/libavcodec/vp6.c
@@ -236,7 +236,7 @@ static int vp6_build_huff_tree(VP56Context *s, uint8_t coeff_model[],
                               FF_HUFFMAN_FLAG_HNODE_FIRST);
 }
 
-static void vp6_parse_coeff_models(VP56Context *s)
+static int vp6_parse_coeff_models(VP56Context *s)
 {
     VP56RangeCoder *c = &s->c;
     VP56Model *model = s->modelp;
@@ -281,15 +281,18 @@ static void vp6_parse_coeff_models(VP56Context *s)
 
     if (s->use_huffman) {
         for (pt=0; pt<2; pt++) {
-            vp6_build_huff_tree(s, model->coeff_dccv[pt],
-                                vp6_huff_coeff_map, 12, &s->dccv_vlc[pt]);
-            vp6_build_huff_tree(s, model->coeff_runv[pt],
-                                vp6_huff_run_map, 9, &s->runv_vlc[pt]);
+            if (vp6_build_huff_tree(s, model->coeff_dccv[pt],
+                                    vp6_huff_coeff_map, 12, &s->dccv_vlc[pt]))
+                return -1;
+            if (vp6_build_huff_tree(s, model->coeff_runv[pt],
+                                    vp6_huff_run_map, 9, &s->runv_vlc[pt]))
+                return -1;
             for (ct=0; ct<3; ct++)
                 for (cg = 0; cg < 6; cg++)
-                    vp6_build_huff_tree(s, model->coeff_ract[pt][ct][cg],
-                                        vp6_huff_coeff_map, 12,
-                                        &s->ract_vlc[pt][ct][cg]);
+                    if (vp6_build_huff_tree(s, model->coeff_ract[pt][ct][cg],
+                                            vp6_huff_coeff_map, 12,
+                                            &s->ract_vlc[pt][ct][cg]))
+                        return -1;
         }
         memset(s->nb_null, 0, sizeof(s->nb_null));
     } else {
@@ -299,6 +302,7 @@ static void vp6_parse_coeff_models(VP56Context *s)
             for (node=0; node<5; node++)
                 model->coeff_dcct[pt][ctx][node] = av_clip(((model->coeff_dccv[pt][node] * vp6_dccv_lc[ctx][node][0] + 128) >> 8) + vp6_dccv_lc[ctx][node][1], 1, 255);
     }
+    return 0;
 }
 
 static void vp6_parse_vector_adjustment(VP56Context *s, VP56mv *vect)
-- 
1.7.2.5