avcodec/smacker: cleanup on errors in smka_decode_frame()

Fixes: multiple memleaks
Fixes: 17660/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_SMACKAUD_fuzzer-5689769928949760
Fixes: 18064/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_SMACKAUD_fuzzer-5631086809317376

Found-by: continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/projects/ffmpegSigned-off-by: Michael Niedermayer <michael@niedermayer.cc>

libavcodec/smacker.c

@@ -721,8 +721,10 @@ static int smka_decode_frame(AVCodecContext *avctx, void *data,
         for(i = 0; i <= stereo; i++)
             *samples++ = pred[i];
         for(; i < unp_size / 2; i++) {
-            if(get_bits_left(&gb)<0)
-                return AVERROR_INVALIDDATA;
+            if (get_bits_left(&gb) < 0) {
+                ret = AVERROR_INVALIDDATA;
+                goto error;
+            }
             if(i & stereo) {
                 if(vlc[2].table)
                     res = get_vlc2(&gb, vlc[2].table, SMKTREE_BITS, 3);
@@ -730,7 +732,8 @@ static int smka_decode_frame(AVCodecContext *avctx, void *data,
                     res = 0;
                 if (res < 0) {
                     av_log(avctx, AV_LOG_ERROR, "invalid vlc\n");
-                    return AVERROR_INVALIDDATA;
+                    ret = AVERROR_INVALIDDATA;
+                    goto error;
                 }
                 val  = h[2].values[res];
                 if(vlc[3].table)
@@ -739,7 +742,8 @@ static int smka_decode_frame(AVCodecContext *avctx, void *data,
                     res = 0;
                 if (res < 0) {
                     av_log(avctx, AV_LOG_ERROR, "invalid vlc\n");
-                    return AVERROR_INVALIDDATA;
+                    ret = AVERROR_INVALIDDATA;
+                    goto error;
                 }
                 val |= h[3].values[res] << 8;
                 pred[1] += sign_extend(val, 16);
@@ -751,7 +755,8 @@ static int smka_decode_frame(AVCodecContext *avctx, void *data,
                     res = 0;
                 if (res < 0) {
                     av_log(avctx, AV_LOG_ERROR, "invalid vlc\n");
-                    return AVERROR_INVALIDDATA;
+                    ret = AVERROR_INVALIDDATA;
+                    goto error;
                 }
                 val  = h[0].values[res];
                 if(vlc[1].table)
@@ -760,7 +765,8 @@ static int smka_decode_frame(AVCodecContext *avctx, void *data,
                     res = 0;
                 if (res < 0) {
                     av_log(avctx, AV_LOG_ERROR, "invalid vlc\n");
-                    return AVERROR_INVALIDDATA;
+                    ret = AVERROR_INVALIDDATA;
+                    goto error;
                 }
                 val |= h[1].values[res] << 8;
                 pred[0] += sign_extend(val, 16);
@@ -773,8 +779,10 @@ static int smka_decode_frame(AVCodecContext *avctx, void *data,
         for(i = 0; i <= stereo; i++)
             *samples8++ = pred[i];
         for(; i < unp_size; i++) {
-            if(get_bits_left(&gb)<0)
-                return AVERROR_INVALIDDATA;
+            if (get_bits_left(&gb) < 0) {
+                ret = AVERROR_INVALIDDATA;
+                goto error;
+            }
             if(i & stereo){
                 if(vlc[1].table)
                     res = get_vlc2(&gb, vlc[1].table, SMKTREE_BITS, 3);
@@ -782,7 +790,8 @@ static int smka_decode_frame(AVCodecContext *avctx, void *data,
                     res = 0;
                 if (res < 0) {
                     av_log(avctx, AV_LOG_ERROR, "invalid vlc\n");
-                    return AVERROR_INVALIDDATA;
+                    ret = AVERROR_INVALIDDATA;
+                    goto error;
                 }
                 pred[1] += sign_extend(h[1].values[res], 8);
                 *samples8++ = pred[1];
@@ -793,7 +802,8 @@ static int smka_decode_frame(AVCodecContext *avctx, void *data,
                     res = 0;
                 if (res < 0) {
                     av_log(avctx, AV_LOG_ERROR, "invalid vlc\n");
-                    return AVERROR_INVALIDDATA;
+                    ret = AVERROR_INVALIDDATA;
+                    goto error;
                 }
                 pred[0] += sign_extend(h[0].values[res], 8);
                 *samples8++ = pred[0];