oggdec: check memory allocation

libavformat/oggdec.c

@@ -160,8 +160,13 @@ static int ogg_new_stream(AVFormatContext *s, uint32_t serial, int new_avstream)
     AVStream *st;
     struct ogg_stream *os;
 
-    ogg->streams = av_realloc(ogg->streams,
-                              ogg->nstreams * sizeof(*ogg->streams));
+    os = av_realloc(ogg->streams, ogg->nstreams * sizeof(*ogg->streams));
+
+    if (!os)
+        return AVERROR(ENOMEM);
+
+    ogg->streams = os;
+
     memset(ogg->streams + idx, 0, sizeof(*ogg->streams));
 
     os                = ogg->streams + idx;
@@ -305,6 +310,8 @@ static int ogg_read_page(AVFormatContext *s, int *str)
 
     if (os->bufsize - os->bufpos < size) {
         uint8_t *nb = av_malloc((os->bufsize *= 2) + FF_INPUT_BUFFER_PADDING_SIZE);
+        if (!nb)
+            return AVERROR(ENOMEM);
         memcpy(nb, os->buf, os->bufpos);
         av_free(os->buf);
         os->buf = nb;