avcodec/smacker: Check space before decoding type

Fixes: Timeout (232sec -> 280ms)
Fixes: 19682/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_SMACKER_fuzzer-5654129649385472
Found-by: continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg
Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>

diff --git a/libavcodec/smacker.c b/libavcodec/smacker.c
index 4c208311552ea383d01b38c5d1ebc8c13bbf8d1f..b4c463b4b92673b0a4ebe8a0a60631a23ff6eb07 100644 (file)
--- a/libavcodec/smacker.c
+++ b/libavcodec/smacker.c
@@ -398,6 +398,8 @@ static av_always_inline int smk_get_code(GetBitContext *gb, int *recode, int *la
     int v;
 
     while(*table & SMK_NODE) {
+        if (get_bits_left(gb) < 1)
+            return AVERROR_INVALIDDATA;
         if(get_bits1(gb))
             table += (*table) & (~SMK_NODE);
         table++;
@@ -462,6 +464,8 @@ static int decode_frame(AVCodecContext *avctx, void *data, int *got_frame,
         uint16_t pix;
 
         type = smk_get_code(&gb, smk->type_tbl, smk->type_last);
+        if (type < 0)
+            return type;
         run = block_runs[(type >> 2) & 0x3F];
         switch(type & 3){
         case SMK_BLK_MONO: