lavf/oggdec: rework allocations in ogg_new_streams().

libavformat/oggdec.c

@@ -165,28 +165,36 @@ static int ogg_new_stream(AVFormatContext *s, uint32_t serial, int new_avstream)
 {
 
     struct ogg *ogg = s->priv_data;
-    int idx = ogg->nstreams++;
+    int idx = ogg->nstreams;
     AVStream *st;
     struct ogg_stream *os;
+    size_t size;
 
-    ogg->streams = av_realloc (ogg->streams,
-                               ogg->nstreams * sizeof (*ogg->streams));
+    if (av_size_mult(ogg->nstreams + 1, sizeof(*ogg->streams), &size) < 0 ||
+        !(os = av_realloc(ogg->streams, size)))
+        return AVERROR(ENOMEM);
+    ogg->streams = os;
     memset (ogg->streams + idx, 0, sizeof (*ogg->streams));
     os = ogg->streams + idx;
     os->serial = serial;
     os->bufsize = DECODER_BUFFER_SIZE;
     os->buf = av_malloc(os->bufsize + FF_INPUT_BUFFER_PADDING_SIZE);
     os->header = -1;
+    if (!os->buf)
+        return AVERROR(ENOMEM);
 
     if (new_avstream) {
         st = avformat_new_stream(s, NULL);
-        if (!st)
+        if (!st) {
+            av_freep(&os->buf);
             return AVERROR(ENOMEM);
+        }
 
         st->id = idx;
         avpriv_set_pts_info(st, 64, 1, 1000000);
     }
 
+    ogg->nstreams++;
     return idx;
 }