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Change fuzzer_encoder_v2 timeout prevention

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This commit is contained in:
Martijn van Beurden 2022-06-10 21:20:04 +02:00
parent 3528fa292a
commit 9b3826006a
1 changed files with 25 additions and 8 deletions
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33
oss-fuzz/fuzzer_encoder_v2.cc
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@ -57,7 +57,7 @@ extern "C" int LLVMFuzzerTestOneInput(const uint8_t *data, size_t size)
FLAC__StreamMetadata_VorbisComment_Entry VorbisCommentField;
unsigned sample_rate, channels, bps;
uint64_t samples_estimate;
uint64_t samples_estimate, samples_in_input;
unsigned compression_level, input_data_width, blocksize, max_lpc_order, qlp_coeff_precision, min_residual_partition_order, max_residual_partition_order, metadata_mask, instruction_set_disable_mask;
FLAC__bool ogg, write_to_file, interleaved;
@ -85,6 +85,7 @@ extern "C" int LLVMFuzzerTestOneInput(const uint8_t *data, size_t size)
compression_level = data[10]&0b1111;
input_data_width = 1 + (data[10]>>4)%4;
samples_in_input = (size-20)/input_data_width;
blocksize = ((unsigned)data[11] << 8) + (unsigned)data[12];
max_lpc_order = data[13];
qlp_coeff_precision = data[14];
@ -113,21 +114,37 @@ extern "C" int LLVMFuzzerTestOneInput(const uint8_t *data, size_t size)
encoder_valid &= FLAC__stream_encoder_set_compression_level(encoder, compression_level);
if(data_bools[3]){
/* Bias towards regular compression levels */
encoder_valid &= FLAC__stream_encoder_set_streamable_subset(encoder, data_bools[4]);
encoder_valid &= FLAC__stream_encoder_set_blocksize(encoder, blocksize);
encoder_valid &= FLAC__stream_encoder_set_max_lpc_order(encoder, max_lpc_order);
encoder_valid &= FLAC__stream_encoder_set_qlp_coeff_precision(encoder, qlp_coeff_precision);
encoder_valid &= FLAC__stream_encoder_set_min_residual_partition_order(encoder, min_residual_partition_order);
encoder_valid &= FLAC__stream_encoder_set_max_residual_partition_order(encoder, max_residual_partition_order);
if(size < (1 << 18)) {
/* The following three options are **slow**, and when combined with a large input
* make fuzzers timeout, so only enable them on reasonably sized inputs. 2^17 is taken
* because that is the maximum blocksize * 4 (32-bit input)
*/
/* With large inputs and expensive options enabled, the fuzzer can get *really* slow.
* Some combinations can make the fuzzer timeout (>60 seconds). However, while combining
* options makes the fuzzer slower, most options do not expose new code when combined.
* Therefore, combining slow options is disabled for large inputs. Any input containing
* more than 65536 * 2 samples (max blocksize, stereo) is considered large
*/
if(samples_in_input < (2*65536)) {
encoder_valid &= FLAC__stream_encoder_set_streamable_subset(encoder, data_bools[4]);
encoder_valid &= FLAC__stream_encoder_set_do_qlp_coeff_prec_search(encoder, data_bools[5]);
encoder_valid &= FLAC__stream_encoder_set_do_escape_coding(encoder, data_bools[6]);
encoder_valid &= FLAC__stream_encoder_set_do_exhaustive_model_search(encoder, data_bools[7]);
/* Combining model search, precision search and a high residual partition order is especially
* expensive, so limit that even further. This high partition order can only be set on
* large blocksize and with streamable subset disabled */
if(samples_in_input < (2 * 4609) || data_bools[4] || !data_bools[7] || !data_bools[5] || max_residual_partition_order < 9 || blocksize < 4609)
encoder_valid &= FLAC__stream_encoder_set_max_residual_partition_order(encoder, max_residual_partition_order);
}
else {
if(data_bools[4])
encoder_valid &= FLAC__stream_encoder_set_streamable_subset(encoder, true);
else if(data_bools[6])
encoder_valid &= FLAC__stream_encoder_set_do_escape_coding(encoder, true);
else if(data_bools[7])
encoder_valid &= FLAC__stream_encoder_set_do_exhaustive_model_search(encoder, true);
else if(data_bools[5])
encoder_valid &= FLAC__stream_encoder_set_do_qlp_coeff_prec_search(encoder, true);
}
encoder_valid &= FLAC__stream_encoder_set_do_mid_side_stereo(encoder, data_bools[8]);
encoder_valid &= FLAC__stream_encoder_set_loose_mid_side_stereo(encoder, data_bools[9]);