avformat/aiffdec: avoid integer overflow in get_meta()

Fixes: signed integer overflow: 2147483647 + 1 cannot be represented in type 'int'
Fixes: 45891/clusterfuzz-testcase-minimized-ffmpeg_dem_AIFF_fuzzer-6159183893889024

Found-by: continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg
Signed-off-by: Michael Niedermayer <[email protected]>

Author: michaelni

libavformat/aiffdec.c

@@ -73,7 +73,7 @@ static int get_tag(AVIOContext *pb, uint32_t * tag)
 /* Metadata string read */
 static void get_meta(AVFormatContext *s, const char *key, int size)
 {
-    uint8_t *str = av_malloc(size+1);
+    uint8_t *str = av_malloc(size+1U);
 
     if (str) {
         int res = avio_read(s->pb, str, size);