[FFmpeg-cvslog] avcodec/smacker: Check space before decoding type

[Michael Niedermayer]

ffmpeg | branch: master | Michael Niedermayer <michael at niedermayer.cc> | Wed Jan  1 20:43:05 2020 +0100| [6f5c18da5977a3214e1ea30e6b0c0d9d858ce83d] | committer: Michael Niedermayer

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 at niedermayer.cc>

> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=6f5c18da5977a3214e1ea30e6b0c0d9d858ce83d
---

 libavcodec/smacker.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/libavcodec/smacker.c b/libavcodec/smacker.c
index 4c20831155..b4c463b4b9 100644
--- 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: