avformat/icodec: Free ico->images on error paths

Fixes: 15116/clusterfuzz-testcase-minimized-ffmpeg_DEMUXER_fuzzer-5715173567889408
Fixes: memleak

Found-by: continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg
Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>
(cherry picked from commit 54918b5116)
Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>

libavformat/icodec.c

@@ -96,8 +96,10 @@ static int read_header(AVFormatContext *s)
             break;
 
         st = avformat_new_stream(s, NULL);
-        if (!st)
+        if (!st) {
+            av_freep(&ico->images);
             return AVERROR(ENOMEM);
+        }
 
         st->codecpar->codec_type = AVMEDIA_TYPE_VIDEO;
         st->codecpar->width      = avio_r8(pb);
@@ -111,6 +113,7 @@ static int read_header(AVFormatContext *s)
         ico->images[i].size   = avio_rl32(pb);
         if (ico->images[i].size <= 0) {
             av_log(s, AV_LOG_ERROR, "Invalid image size %d\n", ico->images[i].size);
+            av_freep(&ico->images);
             return AVERROR_INVALIDDATA;
         }
         ico->images[i].offset = avio_rl32(pb);
@@ -126,8 +129,10 @@ static int read_header(AVFormatContext *s)
             st->codecpar->height   = 0;
             break;
         case 40:
-            if (ico->images[i].size < 40)
+            if (ico->images[i].size < 40) {
+                av_freep(&ico->images);
                 return AVERROR_INVALIDDATA;
+            }
             st->codecpar->codec_id = AV_CODEC_ID_BMP;
             tmp = avio_rl32(pb);
             if (tmp)
@@ -138,6 +143,7 @@ static int read_header(AVFormatContext *s)
             break;
         default:
             avpriv_request_sample(s, "codec %d", codec);
+            av_freep(&ico->images);
             return AVERROR_INVALIDDATA;
         }
     }