Commit message: issue #27, do not overwrite stack on corrupt RF64 file
CVE: CVE-2018-6767
CWE: CWE-119
Vulnerability description: A stack-based buffer over-read in the ParseRiffHeaderConfig function of cli/riff.c file of WavPack 5.1.0 allows a remote attacker to cause a denial-of-service attack or possibly have unspecified other impact via a maliciously crafted RF64 file.

Project: WavPack

 int WriteRiffHeader (FILE *outfile, WavpackContext *wpc, int64_t total_samples, int qmode)
 {
    int do_rf64 = 0, write_junk = 1, table_length = 0;
     ChunkHeader ds64hdr, datahdr, fmthdr;
     RiffChunkHeader riffhdr;
     DS64Chunk ds64_chunk;
    CS64Chunk cs64_chunk;
     JunkChunk junkchunk;
     WaveHeader wavhdr;
     uint32_t bcount;

    int64_t total_data_bytes, total_riff_bytes;
    int num_channels = WavpackGetNumChannels (wpc);
    int32_t channel_mask = WavpackGetChannelMask (wpc);
    int32_t sample_rate = WavpackGetSampleRate (wpc);
    int bytes_per_sample = WavpackGetBytesPerSample (wpc);
    int bits_per_sample = WavpackGetBitsPerSample (wpc);
    int format = WavpackGetFloatNormExp (wpc) ? 3 : 1;
    int wavhdrsize = 16;

    if (format == 3 && WavpackGetFloatNormExp (wpc) != 127) {
        error_line ("can't create valid RIFF wav header for non-normalized floating data!");
        return FALSE;
    }

    if (total_samples == -1)
        total_samples = 0x7ffff000 / (bytes_per_sample * num_channels);

    total_data_bytes = total_samples * bytes_per_sample * num_channels;

    if (total_data_bytes > 0xff000000) {
        if (debug_logging_mode)
            error_line ("total_data_bytes = %lld, so rf64", total_data_bytes);
        write_junk = 0;
        do_rf64 = 1;
    }
    else if (debug_logging_mode)
        error_line ("total_data_bytes = %lld, so riff", total_data_bytes);

    CLEAR (wavhdr);

    wavhdr.FormatTag = format;
    wavhdr.NumChannels = num_channels;
    wavhdr.SampleRate = sample_rate;
    wavhdr.BytesPerSecond = sample_rate * num_channels * bytes_per_sample;
    wavhdr.BlockAlign = bytes_per_sample * num_channels;
    wavhdr.BitsPerSample = bits_per_sample;

    if (num_channels > 2 || channel_mask != 0x5 - num_channels) {
        wavhdrsize = sizeof (wavhdr);
        wavhdr.cbSize = 22;
        wavhdr.ValidBitsPerSample = bits_per_sample;
        wavhdr.SubFormat = format;
        wavhdr.ChannelMask = channel_mask;
        wavhdr.FormatTag = 0xfffe;
        wavhdr.BitsPerSample = bytes_per_sample * 8;
        wavhdr.GUID [4] = 0x10;
        wavhdr.GUID [6] = 0x80;
        wavhdr.GUID [9] = 0xaa;
        wavhdr.GUID [11] = 0x38;
        wavhdr.GUID [12] = 0x9b;
        wavhdr.GUID [13] = 0x71;
    }

    strncpy (riffhdr.ckID, do_rf64 ? "RF64" : "RIFF", sizeof (riffhdr.ckID));
     strncpy (riffhdr.formType, "WAVE", sizeof (riffhdr.formType));
     total_riff_bytes = sizeof (riffhdr) + wavhdrsize + sizeof (datahdr) + ((total_data_bytes + 1) & ~(int64_t)1);
     if (do_rf64) total_riff_bytes += sizeof (ds64hdr) + sizeof (ds64_chunk);
    total_riff_bytes += table_length * sizeof (CS64Chunk);
     if (write_junk) total_riff_bytes += sizeof (junkchunk);
     strncpy (fmthdr.ckID, "fmt ", sizeof (fmthdr.ckID));
     strncpy (datahdr.ckID, "data", sizeof (datahdr.ckID));
    fmthdr.ckSize = wavhdrsize;

    if (write_junk) {
        CLEAR (junkchunk);
        strncpy (junkchunk.ckID, "junk", sizeof (junkchunk.ckID));
        junkchunk.ckSize = sizeof (junkchunk) - 8;
        WavpackNativeToLittleEndian (&junkchunk, ChunkHeaderFormat);
    }
 
     if (do_rf64) {
         strncpy (ds64hdr.ckID, "ds64", sizeof (ds64hdr.ckID));
        ds64hdr.ckSize = sizeof (ds64_chunk) + (table_length * sizeof (CS64Chunk));
         CLEAR (ds64_chunk);
         ds64_chunk.riffSize64 = total_riff_bytes;
         ds64_chunk.dataSize64 = total_data_bytes;
         ds64_chunk.sampleCount64 = total_samples;
        ds64_chunk.tableLength = table_length;
         riffhdr.ckSize = (uint32_t) -1;
         datahdr.ckSize = (uint32_t) -1;
         WavpackNativeToLittleEndian (&ds64hdr, ChunkHeaderFormat);
        WavpackNativeToLittleEndian (&ds64_chunk, DS64ChunkFormat);
    }
    else {
        riffhdr.ckSize = (uint32_t) total_riff_bytes;
         datahdr.ckSize = (uint32_t) total_data_bytes;
     }
 
    // this "table" is just a dummy placeholder for testing (normally not written)

    if (table_length) {
        strncpy (cs64_chunk.ckID, "dmmy", sizeof (cs64_chunk.ckID));
        cs64_chunk.chunkSize64 = 12345678;
        WavpackNativeToLittleEndian (&cs64_chunk, CS64ChunkFormat);
    }

 
     WavpackNativeToLittleEndian (&riffhdr, ChunkHeaderFormat);
    WavpackNativeToLittleEndian (&fmthdr, ChunkHeaderFormat);
    WavpackNativeToLittleEndian (&wavhdr, WaveHeaderFormat);
    WavpackNativeToLittleEndian (&datahdr, ChunkHeaderFormat);
 
     if (!DoWriteFile (outfile, &riffhdr, sizeof (riffhdr), &bcount) || bcount != sizeof (riffhdr) ||
         (do_rf64 && (!DoWriteFile (outfile, &ds64hdr, sizeof (ds64hdr), &bcount) || bcount != sizeof (ds64hdr))) ||
        (do_rf64 && (!DoWriteFile (outfile, &ds64_chunk, sizeof (ds64_chunk), &bcount) || bcount != sizeof (ds64_chunk)))) {
            error_line ("can't write .WAV data, disk probably full!");
            return FALSE;
    }

    // again, this is normally not written except for testing

    while (table_length--)
        if (!DoWriteFile (outfile, &cs64_chunk, sizeof (cs64_chunk), &bcount) || bcount != sizeof (cs64_chunk)) {
            error_line ("can't write .WAV data, disk probably full!");
            return FALSE;
        }


    if ((write_junk && (!DoWriteFile (outfile, &junkchunk, sizeof (junkchunk), &bcount) || bcount != sizeof (junkchunk))) ||
         !DoWriteFile (outfile, &fmthdr, sizeof (fmthdr), &bcount) || bcount != sizeof (fmthdr) ||
         !DoWriteFile (outfile, &wavhdr, wavhdrsize, &bcount) || bcount != wavhdrsize ||
         !DoWriteFile (outfile, &datahdr, sizeof (datahdr), &bcount) || bcount != sizeof (datahdr)) {
            error_line ("can't write .WAV data, disk probably full!");
            return FALSE;
    }

    return TRUE;
}