Bug 1351600 - Add DTLS client and server fuzzers r=franziskus

Differential Revision: https://nss-review.dev.mozaws.net/D282

9 files changed, 150 insertions, 50 deletions

diff --git a/fuzz/fuzz.gyp b/fuzz/fuzz.gyp
index da52d6e37..a7339b78c 100644
--- a/fuzz/fuzz.gyp
+++ b/fuzz/fuzz.gyp
@@ -301,10 +301,45 @@
       ],
     },
     {
+      'target_name': 'nssfuzz-dtls-client',
+      'type': 'executable',
+      'sources': [
+        'tls_client_config.cc',
+        'tls_client_target.cc',
+      ],
+      'defines': [
+        'IS_DTLS'
+      ],
+      'dependencies': [
+        '<(DEPTH)/exports.gyp:nss_exports',
+        '<(DEPTH)/cpputil/cpputil.gyp:cpputil',
+        'nssfuzz-tls-base',
+      ],
+    },
+    {
+      'target_name': 'nssfuzz-dtls-server',
+      'type': 'executable',
+      'sources': [
+        'tls_server_certs.cc',
+        'tls_server_config.cc',
+        'tls_server_target.cc',
+      ],
+      'defines': [
+        'IS_DTLS'
+      ],
+      'dependencies': [
+        '<(DEPTH)/exports.gyp:nss_exports',
+        '<(DEPTH)/cpputil/cpputil.gyp:cpputil',
+        'nssfuzz-tls-base',
+      ],
+    },
+    {
       'target_name': 'nssfuzz',
       'type': 'none',
       'dependencies': [
         'nssfuzz-certDN',
+        'nssfuzz-dtls-client',
+        'nssfuzz-dtls-server',
         'nssfuzz-pkcs8',
         'nssfuzz-quickder',
         'nssfuzz-tls-client',
diff --git a/fuzz/options/dtls-client-no_fuzzer_mode.options b/fuzz/options/dtls-client-no_fuzzer_mode.options
new file mode 100644
index 000000000..8b017d2ce
--- /dev/null
+++ b/fuzz/options/dtls-client-no_fuzzer_mode.options
@@ -0,0 +1,3 @@
+[libfuzzer]
+max_len = 20000
+
diff --git a/fuzz/options/dtls-client.options b/fuzz/options/dtls-client.options
new file mode 100644
index 000000000..8b017d2ce
--- /dev/null
+++ b/fuzz/options/dtls-client.options
@@ -0,0 +1,3 @@
+[libfuzzer]
+max_len = 20000
+
diff --git a/fuzz/options/dtls-server-no_fuzzer_mode.options b/fuzz/options/dtls-server-no_fuzzer_mode.options
new file mode 100644
index 000000000..8b017d2ce
--- /dev/null
+++ b/fuzz/options/dtls-server-no_fuzzer_mode.options
@@ -0,0 +1,3 @@
+[libfuzzer]
+max_len = 20000
+
diff --git a/fuzz/options/dtls-server.options b/fuzz/options/dtls-server.options
new file mode 100644
index 000000000..8b017d2ce
--- /dev/null
+++ b/fuzz/options/dtls-server.options
@@ -0,0 +1,3 @@
+[libfuzzer]
+max_len = 20000
+
diff --git a/fuzz/tls_client_target.cc b/fuzz/tls_client_target.cc
index 82e4a5dfb..e59550984 100644
--- a/fuzz/tls_client_target.cc
+++ b/fuzz/tls_client_target.cc
@@ -16,6 +16,20 @@
 #include "tls_mutators.h"
 #include "tls_socket.h"
 
+#ifdef IS_DTLS
+__attribute__((constructor)) static void set_is_dtls() {
+  TlsMutators::SetIsDTLS();
+}
+#endif
+
+PRFileDesc* ImportFD(PRFileDesc* model, PRFileDesc* fd) {
+#ifdef IS_DTLS
+  return DTLS_ImportFD(model, fd);
+#else
+  return SSL_ImportFD(model, fd);
+#endif
+}
+
 static SECStatus AuthCertificateHook(void* arg, PRFileDesc* fd, PRBool checksig,
                                      PRBool isServer) {
   assert(!isServer);
@@ -49,9 +63,11 @@ static void SetSocketOptions(PRFileDesc* fd,
                      config->RequireSafeNegotiation());
   assert(rv == SECSuccess);
 
+#ifndef IS_DTLS
   rv =
       SSL_OptionSet(fd, SSL_ENABLE_RENEGOTIATION, SSL_RENEGOTIATE_UNRESTRICTED);
   assert(rv == SECSuccess);
+#endif
 }
 
 // This is only called when we set SSL_ENABLE_FALSE_START=1,
@@ -87,7 +103,7 @@ extern "C" int LLVMFuzzerTestOneInput(const uint8_t* data, size_t len) {
   std::unique_ptr<DummyPrSocket> socket(new DummyPrSocket(data, len));
   static PRDescIdentity id = PR_GetUniqueIdentity("fuzz-client");
   ScopedPRFileDesc fd(DummyIOLayerMethods::CreateFD(id, socket.get()));
-  PRFileDesc* ssl_fd = SSL_ImportFD(nullptr, fd.get());
+  PRFileDesc* ssl_fd = ImportFD(nullptr, fd.get());
   assert(ssl_fd == fd.get());
 
   // Probably not too important for clients.
@@ -103,9 +119,9 @@ extern "C" int LLVMFuzzerTestOneInput(const uint8_t* data, size_t len) {
 
 extern "C" size_t LLVMFuzzerCustomMutator(uint8_t* data, size_t size,
                                           size_t max_size, unsigned int seed) {
-  return CustomMutate({TlsMutatorDropRecord, TlsMutatorShuffleRecords,
-                       TlsMutatorDuplicateRecord, TlsMutatorTruncateRecord,
-                       TlsMutatorFragmentRecord},
+  using namespace TlsMutators;
+  return CustomMutate({DropRecord, ShuffleRecords, DuplicateRecord,
+                       TruncateRecord, FragmentRecord},
                       data, size, max_size, seed);
 }
 
@@ -113,5 +129,6 @@ extern "C" size_t LLVMFuzzerCustomCrossOver(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) {
-  return TlsCrossOver(data1, size1, data2, size2, out, max_out_size, seed);
+  return TlsMutators::CrossOver(data1, size1, data2, size2, out, max_out_size,
+                                seed);
 }
diff --git a/fuzz/tls_mutators.cc b/fuzz/tls_mutators.cc
index ccf1935bf..e9770cb39 100644
--- a/fuzz/tls_mutators.cc
+++ b/fuzz/tls_mutators.cc
@@ -10,6 +10,10 @@
 
 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:
@@ -33,9 +37,9 @@ class Record {
   }
 
   void truncate(size_t length) {
-    assert(length >= 5);
+    assert(length >= 5 + gExtraHeaderBytes);
     uint8_t *dest = const_cast<uint8_t *>(data_);
-    (void)ssl_EncodeUintX(length - 5, 2, &dest[3]);
+    (void)ssl_EncodeUintX(length - 5 - gExtraHeaderBytes, 2, &dest[3]);
     memmove(dest + length, data_ + size_, remaining_);
   }
 
@@ -66,13 +70,8 @@ std::vector<std::unique_ptr<Record>> ParseRecords(const uint8_t *data,
   while (parser.remaining()) {
     size_t offset = parser.consumed();
 
-    uint32_t type;
-    if (!parser.Read(&type, 1)) {
-      break;
-    }
-
-    uint32_t version;
-    if (!parser.Read(&version, 2)) {
+    // Skip type, version, and DTLS seqnums.
+    if (!parser.Skip(3 + gExtraHeaderBytes)) {
       break;
     }
 
@@ -81,16 +80,22 @@ std::vector<std::unique_ptr<Record>> ParseRecords(const uint8_t *data,
       break;
     }
 
-    records.push_back(
-        Record::Create(data + offset, fragment.len() + 5, parser.remaining()));
+    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 TlsMutatorDropRecord(uint8_t *data, size_t size, size_t max_size,
-                            unsigned int seed) {
+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.
@@ -111,8 +116,8 @@ size_t TlsMutatorDropRecord(uint8_t *data, size_t size, size_t max_size,
 }
 
 // Mutator that shuffles TLS records in a transcript.
-size_t TlsMutatorShuffleRecords(uint8_t *data, size_t size, size_t max_size,
-                                unsigned int seed) {
+size_t ShuffleRecords(uint8_t *data, size_t size, size_t max_size,
+                      unsigned int seed) {
   std::mt19937 rng(seed);
 
   // Store the original corpus.
@@ -142,8 +147,8 @@ size_t TlsMutatorShuffleRecords(uint8_t *data, size_t size, size_t max_size,
 }
 
 // Mutator that duplicates a single TLS record and randomly inserts it.
-size_t TlsMutatorDuplicateRecord(uint8_t *data, size_t size, size_t max_size,
-                                 unsigned int seed) {
+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.
@@ -167,8 +172,8 @@ size_t TlsMutatorDuplicateRecord(uint8_t *data, size_t size, size_t max_size,
 }
 
 // Mutator that truncates a TLS record.
-size_t TlsMutatorTruncateRecord(uint8_t *data, size_t size, size_t max_size,
-                                unsigned int seed) {
+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.
@@ -182,12 +187,13 @@ size_t TlsMutatorTruncateRecord(uint8_t *data, size_t size, size_t max_size,
   auto &rec = records.at(dist(rng));
 
   // Need a record with data.
-  if (rec->size() <= 5) {
+  if (rec->size() <= 5 + gExtraHeaderBytes) {
     return 0;
   }
 
   // Truncate.
-  std::uniform_int_distribution<size_t> dist2(5, rec->size() - 1);
+  std::uniform_int_distribution<size_t> dist2(5 + gExtraHeaderBytes,
+                                              rec->size() - 1);
   size_t new_length = dist2(rng);
   rec->truncate(new_length);
 
@@ -196,10 +202,15 @@ size_t TlsMutatorTruncateRecord(uint8_t *data, size_t size, size_t max_size,
 }
 
 // Mutator that splits a TLS record in two.
-size_t TlsMutatorFragmentRecord(uint8_t *data, size_t size, size_t max_size,
-                                unsigned int seed) {
+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;
   }
@@ -238,9 +249,9 @@ size_t TlsMutatorFragmentRecord(uint8_t *data, size_t size, size_t max_size,
 }
 
 // Cross-over function that merges and shuffles two transcripts.
-size_t TlsCrossOver(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) {
+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.
@@ -274,3 +285,5 @@ size_t TlsCrossOver(const uint8_t *data1, size_t size1, const uint8_t *data2,
 
   return total;
 }
+
+}  // namespace TlsMutators
diff --git a/fuzz/tls_mutators.h b/fuzz/tls_mutators.h
index 48429626f..03a214751 100644
--- a/fuzz/tls_mutators.h
+++ b/fuzz/tls_mutators.h
@@ -5,19 +5,25 @@
 #ifndef tls_mutators_h__
 #define tls_mutators_h__
 
-size_t TlsMutatorDropRecord(uint8_t *data, size_t size, size_t max_size,
-                            unsigned int seed);
-size_t TlsMutatorShuffleRecords(uint8_t *data, size_t size, size_t max_size,
-                                unsigned int seed);
-size_t TlsMutatorDuplicateRecord(uint8_t *data, size_t size, size_t max_size,
-                                 unsigned int seed);
-size_t TlsMutatorTruncateRecord(uint8_t *data, size_t size, size_t max_size,
-                                unsigned int seed);
-size_t TlsMutatorFragmentRecord(uint8_t *data, size_t size, size_t max_size,
-                                unsigned int seed);
+namespace TlsMutators {
 
-size_t TlsCrossOver(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);
+void SetIsDTLS();
+
+size_t DropRecord(uint8_t *data, size_t size, size_t max_size,
+                  unsigned int seed);
+size_t ShuffleRecords(uint8_t *data, size_t size, size_t max_size,
+                      unsigned int seed);
+size_t DuplicateRecord(uint8_t *data, size_t size, size_t max_size,
+                       unsigned int seed);
+size_t TruncateRecord(uint8_t *data, size_t size, size_t max_size,
+                      unsigned int seed);
+size_t FragmentRecord(uint8_t *data, size_t size, size_t max_size,
+                      unsigned int seed);
+
+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);
+
+}  // namespace TlsMutators
 
 #endif  // tls_mutators_h__
diff --git a/fuzz/tls_server_target.cc b/fuzz/tls_server_target.cc
index 67193368f..0c0902077 100644
--- a/fuzz/tls_server_target.cc
+++ b/fuzz/tls_server_target.cc
@@ -17,6 +17,20 @@
 #include "tls_server_config.h"
 #include "tls_socket.h"
 
+#ifdef IS_DTLS
+__attribute__((constructor)) static void set_is_dtls() {
+  TlsMutators::SetIsDTLS();
+}
+#endif
+
+PRFileDesc* ImportFD(PRFileDesc* model, PRFileDesc* fd) {
+#ifdef IS_DTLS
+  return DTLS_ImportFD(model, fd);
+#else
+  return SSL_ImportFD(model, fd);
+#endif
+}
+
 class SSLServerSessionCache {
  public:
   SSLServerSessionCache() {
@@ -56,9 +70,11 @@ static void SetSocketOptions(PRFileDesc* fd,
                      config->RequireSafeNegotiation());
   assert(rv == SECSuccess);
 
+#ifndef IS_DTLS
   rv =
       SSL_OptionSet(fd, SSL_ENABLE_RENEGOTIATION, SSL_RENEGOTIATE_UNRESTRICTED);
   assert(rv == SECSuccess);
+#endif
 }
 
 static PRStatus InitModelSocket(void* arg) {
@@ -88,7 +104,7 @@ extern "C" int LLVMFuzzerTestOneInput(const uint8_t* data, size_t len) {
   assert(RNG_RandomUpdate(NULL, 0) == SECSuccess);
 
   // Create model socket.
-  static ScopedPRFileDesc model(SSL_ImportFD(nullptr, PR_NewTCPSocket()));
+  static ScopedPRFileDesc model(ImportFD(nullptr, PR_NewTCPSocket()));
   assert(model);
 
   // Initialize the model socket once.
@@ -99,7 +115,7 @@ extern "C" int LLVMFuzzerTestOneInput(const uint8_t* data, size_t len) {
   std::unique_ptr<DummyPrSocket> socket(new DummyPrSocket(data, len));
   static PRDescIdentity id = PR_GetUniqueIdentity("fuzz-server");
   ScopedPRFileDesc fd(DummyIOLayerMethods::CreateFD(id, socket.get()));
-  PRFileDesc* ssl_fd = SSL_ImportFD(model.get(), fd.get());
+  PRFileDesc* ssl_fd = ImportFD(model.get(), fd.get());
   assert(ssl_fd == fd.get());
 
   SetSocketOptions(ssl_fd, config);
@@ -110,9 +126,9 @@ extern "C" int LLVMFuzzerTestOneInput(const uint8_t* data, size_t len) {
 
 extern "C" size_t LLVMFuzzerCustomMutator(uint8_t* data, size_t size,
                                           size_t max_size, unsigned int seed) {
-  return CustomMutate({TlsMutatorDropRecord, TlsMutatorShuffleRecords,
-                       TlsMutatorDuplicateRecord, TlsMutatorTruncateRecord,
-                       TlsMutatorFragmentRecord},
+  using namespace TlsMutators;
+  return CustomMutate({DropRecord, ShuffleRecords, DuplicateRecord,
+                       TruncateRecord, FragmentRecord},
                       data, size, max_size, seed);
 }
 
@@ -120,5 +136,6 @@ extern "C" size_t LLVMFuzzerCustomCrossOver(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) {
-  return TlsCrossOver(data1, size1, data2, size2, out, max_out_size, seed);
+  return TlsMutators::CrossOver(data1, size1, data2, size2, out, max_out_size,
+                                seed);
 }