mpeg4audio: validate sample_rate

A negative sample rate doesn't make sense and triggers assertions in
av_rescale_rnd.

Also check for errors from avpriv_mpeg4audio_get_config in
ff_mp4_read_dec_config_descr.
Signed-off-by: Andreas Cadhalpun <Andreas.Cadhalpun@googlemail.com>

libavcodec/mpeg4audio.c

@@ -42,6 +42,11 @@ static int parse_config_ALS(GetBitContext *gb, MPEG4AudioConfig *c)
     // which are buggy in old ALS conformance files
     c->sample_rate = get_bits_long(gb, 32);
 
+    if (c->sample_rate <= 0) {
+        av_log(NULL, AV_LOG_ERROR, "Invalid sample rate %d\n", c->sample_rate);
+        return AVERROR_INVALIDDATA;
+    }
+
     // skip number of samples
     skip_bits_long(gb, 32);
 

libavformat/isom.c

@@ -513,8 +513,10 @@ FF_ENABLE_DEPRECATION_WARNINGS
             return ret;
         if (st->codecpar->codec_id == AV_CODEC_ID_AAC) {
             MPEG4AudioConfig cfg = {0};
-            avpriv_mpeg4audio_get_config(&cfg, st->codecpar->extradata,
-                                         st->codecpar->extradata_size * 8, 1);
+            ret = avpriv_mpeg4audio_get_config(&cfg, st->codecpar->extradata,
+                                               st->codecpar->extradata_size * 8, 1);
+            if (ret < 0)
+                return ret;
             st->codecpar->channels = cfg.channels;
             if (cfg.object_type == 29 && cfg.sampling_index < 3) // old mp3on4
                 st->codecpar->sample_rate = avpriv_mpa_freq_tab[cfg.sampling_index];