From f017b749ea9f1586d2308504553d40bf4cc5439d Mon Sep 17 00:00:00 2001 From: wolfbeast Date: Tue, 6 Feb 2018 11:46:26 +0100 Subject: Update NSS to 3.32.1-RTM --- security/nss/fuzz/tls_mutators.cc | 289 ++++++++++++++++++++++++++++++++++++++ 1 file changed, 289 insertions(+) create mode 100644 security/nss/fuzz/tls_mutators.cc (limited to 'security/nss/fuzz/tls_mutators.cc') diff --git a/security/nss/fuzz/tls_mutators.cc b/security/nss/fuzz/tls_mutators.cc new file mode 100644 index 000000000..e9770cb39 --- /dev/null +++ b/security/nss/fuzz/tls_mutators.cc @@ -0,0 +1,289 @@ +/* This Source Code Form is subject to the terms of the Mozilla Public + * License, v. 2.0. If a copy of the MPL was not distributed with this + * file, You can obtain one at http://mozilla.org/MPL/2.0/. */ + +#include "shared.h" +#include "tls_parser.h" + +#include "ssl.h" +#include "sslimpl.h" + +using namespace nss_test; + +// Number of additional bytes in the TLS header. +// Used to properly skip DTLS seqnums. +static size_t gExtraHeaderBytes = 0; + +// Helper class to simplify TLS record manipulation. +class Record { + public: + static std::unique_ptr Create(const uint8_t *data, size_t size, + size_t remaining) { + return std::unique_ptr(new Record(data, size, remaining)); + } + + void insert_before(const std::unique_ptr &other) { + assert(data_ && size_ > 0); + + // Copy data in case other == this. + uint8_t buf[size_]; + memcpy(buf, data_, size_); + + uint8_t *dest = const_cast(other->data()); + // Make room for the record we want to insert. + memmove(dest + size_, other->data(), other->size() + other->remaining()); + // Insert the record. + memcpy(dest, buf, size_); + } + + void truncate(size_t length) { + assert(length >= 5 + gExtraHeaderBytes); + uint8_t *dest = const_cast(data_); + (void)ssl_EncodeUintX(length - 5 - gExtraHeaderBytes, 2, &dest[3]); + memmove(dest + length, data_ + size_, remaining_); + } + + void drop() { + uint8_t *dest = const_cast(data_); + memmove(dest, data_ + size_, remaining_); + } + + const uint8_t *data() { return data_; } + size_t remaining() { return remaining_; } + size_t size() { return size_; } + + private: + Record(const uint8_t *data, size_t size, size_t remaining) + : data_(data), remaining_(remaining), size_(size) {} + + const uint8_t *data_; + size_t remaining_; + size_t size_; +}; + +// Parse records contained in a given TLS transcript. +std::vector> ParseRecords(const uint8_t *data, + size_t size) { + std::vector> records; + TlsParser parser(data, size); + + while (parser.remaining()) { + size_t offset = parser.consumed(); + + // Skip type, version, and DTLS seqnums. + if (!parser.Skip(3 + gExtraHeaderBytes)) { + break; + } + + DataBuffer fragment; + if (!parser.ReadVariable(&fragment, 2)) { + break; + } + + records.push_back(Record::Create(data + offset, + fragment.len() + 5 + gExtraHeaderBytes, + parser.remaining())); + } + + return records; +} + +namespace TlsMutators { + +// Handle seqnums in DTLS transcripts. +void SetIsDTLS() { gExtraHeaderBytes = 8; } + +// Mutator that drops whole TLS records. +size_t DropRecord(uint8_t *data, size_t size, size_t max_size, + unsigned int seed) { + std::mt19937 rng(seed); + + // Find TLS records in the corpus. + auto records = ParseRecords(data, size); + if (records.empty()) { + return 0; + } + + // Pick a record to drop at random. + std::uniform_int_distribution dist(0, records.size() - 1); + auto &rec = records.at(dist(rng)); + + // Drop the record. + rec->drop(); + + // Return the new final size. + return size - rec->size(); +} + +// Mutator that shuffles TLS records in a transcript. +size_t ShuffleRecords(uint8_t *data, size_t size, size_t max_size, + unsigned int seed) { + std::mt19937 rng(seed); + + // Store the original corpus. + uint8_t buf[size]; + memcpy(buf, data, size); + + // Find TLS records in the corpus. + auto records = ParseRecords(buf, sizeof(buf)); + if (records.empty()) { + return 0; + } + + // Find offset of first record in target buffer. + uint8_t *dest = const_cast(ParseRecords(data, size).at(0)->data()); + + // Shuffle record order. + std::shuffle(records.begin(), records.end(), rng); + + // Write records to their new positions. + for (auto &rec : records) { + memcpy(dest, rec->data(), rec->size()); + dest += rec->size(); + } + + // Final size hasn't changed. + return size; +} + +// Mutator that duplicates a single TLS record and randomly inserts it. +size_t DuplicateRecord(uint8_t *data, size_t size, size_t max_size, + unsigned int seed) { + std::mt19937 rng(seed); + + // Find TLS records in the corpus. + const auto records = ParseRecords(data, size); + if (records.empty()) { + return 0; + } + + // Pick a record to duplicate at random. + std::uniform_int_distribution dist(0, records.size() - 1); + auto &rec = records.at(dist(rng)); + if (size + rec->size() > max_size) { + return 0; + } + + // Insert before random record. + rec->insert_before(records.at(dist(rng))); + + // Return the new final size. + return size + rec->size(); +} + +// Mutator that truncates a TLS record. +size_t TruncateRecord(uint8_t *data, size_t size, size_t max_size, + unsigned int seed) { + std::mt19937 rng(seed); + + // Find TLS records in the corpus. + const auto records = ParseRecords(data, size); + if (records.empty()) { + return 0; + } + + // Pick a record to truncate at random. + std::uniform_int_distribution dist(0, records.size() - 1); + auto &rec = records.at(dist(rng)); + + // Need a record with data. + if (rec->size() <= 5 + gExtraHeaderBytes) { + return 0; + } + + // Truncate. + std::uniform_int_distribution dist2(5 + gExtraHeaderBytes, + rec->size() - 1); + size_t new_length = dist2(rng); + rec->truncate(new_length); + + // Return the new final size. + return size + new_length - rec->size(); +} + +// Mutator that splits a TLS record in two. +size_t FragmentRecord(uint8_t *data, size_t size, size_t max_size, + unsigned int seed) { + std::mt19937 rng(seed); + + // We can't deal with DTLS yet. + if (gExtraHeaderBytes > 0) { + return 0; + } + + if (size + 5 > max_size) { + return 0; + } + + // Find TLS records in the corpus. + const auto records = ParseRecords(data, size); + if (records.empty()) { + return 0; + } + + // Pick a record to fragment at random. + std::uniform_int_distribution dist(0, records.size() - 1); + auto &rec = records.at(dist(rng)); + uint8_t *rdata = const_cast(rec->data()); + size_t length = rec->size(); + size_t content_length = length - 5; + + if (content_length < 2) { + return 0; + } + + // Assign a new length to the first fragment. + size_t new_length = content_length / 2; + uint8_t *content = ssl_EncodeUintX(new_length, 2, &rdata[3]); + + // Make room for one more header. + memmove(content + new_length + 5, content + new_length, + rec->remaining() + content_length - new_length); + + // Write second header. + memcpy(content + new_length, rdata, 3); + (void)ssl_EncodeUintX(content_length - new_length, 2, + &content[new_length + 3]); + + return size + 5; +} + +// Cross-over function that merges and shuffles two transcripts. +size_t CrossOver(const uint8_t *data1, size_t size1, const uint8_t *data2, + size_t size2, uint8_t *out, size_t max_out_size, + unsigned int seed) { + std::mt19937 rng(seed); + + // Find TLS records in the corpus. + auto records1 = ParseRecords(data1, size1); + if (records1.empty()) { + return 0; + } + + { // Merge the two vectors. + auto records2 = ParseRecords(data2, size2); + if (records2.empty()) { + return 0; + } + std::move(records2.begin(), records2.end(), std::back_inserter(records1)); + } + + // Shuffle record order. + std::shuffle(records1.begin(), records1.end(), rng); + + size_t total = 0; + for (auto &rec : records1) { + size_t length = rec->size(); + if (total + length > max_out_size) { + break; + } + + // Write record to its new position. + memcpy(out + total, rec->data(), length); + total += length; + } + + return total; +} + +} // namespace TlsMutators -- cgit v1.2.3