Move PrivateKeyInfoCodec to rsa_private_key_nss.cc

crypto/rsa_private_key_nss.cc

Index: crypto/rsa_private_key_nss.cc
diff --git a/crypto/rsa_private_key_nss.cc b/crypto/rsa_private_key_nss.cc
index 349b7ea6cd00ec7e2da1b08edee2bc2b8aec23d3..3135316e962d1bb4992e6f3165ce2e03159ab669 100644
--- a/crypto/rsa_private_key_nss.cc
+++ b/crypto/rsa_private_key_nss.cc
@@ -19,6 +19,13 @@
 #include "crypto/nss_util.h"
 #include "crypto/scoped_nss_types.h"
 
+// Helper for error handling during key import.
+#define READ_ASSERT(truth) \
+  if (!(truth)) { \
+    NOTREACHED(); \
+    return false; \
+  }
+
 // TODO(rafaelw): Consider using NSS's ASN.1 encoder.
 namespace {
 
@@ -38,6 +45,481 @@ static bool ReadAttribute(SECKEYPrivateKey* key,
   return true;
 }
 
+// Used internally by RSAPrivateKey for serializing and deserializing
+// PKCS #8 PrivateKeyInfo and PublicKeyInfo.
+class PrivateKeyInfoCodec {
+ public:
+  // ASN.1 encoding of the AlgorithmIdentifier from PKCS #8.
+  static const uint8_t kRsaAlgorithmIdentifier[];
+
+  // ASN.1 tags for some types we use.
+  static const uint8_t kBitStringTag = 0x03;
+  static const uint8_t kIntegerTag = 0x02;
+  static const uint8_t kNullTag = 0x05;

[nharper, 2016/03/23 22:08:14]

iOS compile is complaining this is unused - I'd remove it.

[davidben, 2016/03/23 22:23:50]

Done.

+  static const uint8_t kOctetStringTag = 0x04;
+  static const uint8_t kSequenceTag = 0x30;
+
+  // |big_endian| here specifies the byte-significance of the integer components
+  // that will be parsed & serialized (modulus(), etc...) during Import(),
+  // Export() and ExportPublicKeyInfo() -- not the ASN.1 DER encoding of the
+  // PrivateKeyInfo/PublicKeyInfo (which is always big-endian).
+  explicit PrivateKeyInfoCodec(bool big_endian);
+
+  ~PrivateKeyInfoCodec();
+
+  // Exports the contents of the integer components to the ASN.1 DER encoding
+  // of the PrivateKeyInfo structure to |output|.
+  bool Export(std::vector<uint8_t>* output);
+
+  // Exports the contents of the integer components to the ASN.1 DER encoding
+  // of the PublicKeyInfo structure to |output|.
+  bool ExportPublicKeyInfo(std::vector<uint8_t>* output);
+
+  // Exports the contents of the integer components to the ASN.1 DER encoding
+  // of the RSAPublicKey structure to |output|.
+  bool ExportPublicKey(std::vector<uint8_t>* output);
+
+  // Parses the ASN.1 DER encoding of the PrivateKeyInfo structure in |input|
+  // and populates the integer components with |big_endian_| byte-significance.
+  // IMPORTANT NOTE: This is currently *not* security-approved for importing
+  // keys from unstrusted sources.
+  bool Import(const std::vector<uint8_t>& input);
+
+  // Accessors to the contents of the integer components of the PrivateKeyInfo
+  // structure.
+  std::vector<uint8_t>* modulus() { return &modulus_; }
+  std::vector<uint8_t>* public_exponent() { return &public_exponent_; }
+  std::vector<uint8_t>* private_exponent() { return &private_exponent_; }
+  std::vector<uint8_t>* prime1() { return &prime1_; }
+  std::vector<uint8_t>* prime2() { return &prime2_; }
+  std::vector<uint8_t>* exponent1() { return &exponent1_; }
+  std::vector<uint8_t>* exponent2() { return &exponent2_; }
+  std::vector<uint8_t>* coefficient() { return &coefficient_; }
+
+ private:
+  // Utility wrappers for PrependIntegerImpl that use the class's |big_endian_|
+  // value.
+  void PrependInteger(const std::vector<uint8_t>& in, std::list<uint8_t>* out);
+  void PrependInteger(uint8_t* val, int num_bytes, std::list<uint8_t>* data);
+
+  // Prepends the integer stored in |val| - |val + num_bytes| with |big_endian|
+  // byte-significance into |data| as an ASN.1 integer.
+  void PrependIntegerImpl(uint8_t* val,
+                          int num_bytes,
+                          std::list<uint8_t>* data,
+                          bool big_endian);
+
+  // Utility wrappers for ReadIntegerImpl that use the class's |big_endian_|
+  // value.
+  bool ReadInteger(uint8_t** pos, uint8_t* end, std::vector<uint8_t>* out);
+  bool ReadIntegerWithExpectedSize(uint8_t** pos,
+                                   uint8_t* end,
+                                   size_t expected_size,
+                                   std::vector<uint8_t>* out);
+
+  // Reads an ASN.1 integer from |pos|, and stores the result into |out| with
+  // |big_endian| byte-significance.
+  bool ReadIntegerImpl(uint8_t** pos,
+                       uint8_t* end,
+                       std::vector<uint8_t>* out,
+                       bool big_endian);
+
+  // Prepends the integer stored in |val|, starting a index |start|, for
+  // |num_bytes| bytes onto |data|.
+  void PrependBytes(uint8_t* val,
+                    int start,
+                    int num_bytes,
+                    std::list<uint8_t>* data);
+
+  // Helper to prepend an ASN.1 length field.
+  void PrependLength(size_t size, std::list<uint8_t>* data);
+
+  // Helper to prepend an ASN.1 type header.
+  void PrependTypeHeaderAndLength(uint8_t type,
+                                  uint32_t length,
+                                  std::list<uint8_t>* output);
+
+  // Helper to prepend an ASN.1 bit string
+  void PrependBitString(uint8_t* val,
+                        int num_bytes,
+                        std::list<uint8_t>* output);
+
+  // Read an ASN.1 length field. This also checks that the length does not
+  // extend beyond |end|.
+  bool ReadLength(uint8_t** pos, uint8_t* end, uint32_t* result);
+
+  // Read an ASN.1 type header and its length.
+  bool ReadTypeHeaderAndLength(uint8_t** pos,
+                               uint8_t* end,
+                               uint8_t expected_tag,
+                               uint32_t* length);
+
+  // Read an ASN.1 sequence declaration. This consumes the type header and
+  // length field, but not the contents of the sequence.
+  bool ReadSequence(uint8_t** pos, uint8_t* end);
+
+  // Read the RSA AlgorithmIdentifier.
+  bool ReadAlgorithmIdentifier(uint8_t** pos, uint8_t* end);
+
+  // Read one of the two version fields in PrivateKeyInfo.
+  bool ReadVersion(uint8_t** pos, uint8_t* end);
+
+  // The byte-significance of the stored components (modulus, etc..).
+  bool big_endian_;
+
+  // Component integers of the PrivateKeyInfo
+  std::vector<uint8_t> modulus_;
+  std::vector<uint8_t> public_exponent_;
+  std::vector<uint8_t> private_exponent_;
+  std::vector<uint8_t> prime1_;
+  std::vector<uint8_t> prime2_;
+  std::vector<uint8_t> exponent1_;
+  std::vector<uint8_t> exponent2_;
+  std::vector<uint8_t> coefficient_;
+
+  DISALLOW_COPY_AND_ASSIGN(PrivateKeyInfoCodec);
+};
+
+const uint8_t PrivateKeyInfoCodec::kRsaAlgorithmIdentifier[] = {
+    0x30, 0x0D, 0x06, 0x09, 0x2A, 0x86, 0x48, 0x86,
+    0xF7, 0x0D, 0x01, 0x01, 0x01, 0x05, 0x00};
+
+PrivateKeyInfoCodec::PrivateKeyInfoCodec(bool big_endian)
+    : big_endian_(big_endian) {}
+
+PrivateKeyInfoCodec::~PrivateKeyInfoCodec() {}
+
+bool PrivateKeyInfoCodec::Export(std::vector<uint8_t>* output) {
+  std::list<uint8_t> content;
+
+  // Version (always zero)
+  uint8_t version = 0;
+
+  PrependInteger(coefficient_, &content);
+  PrependInteger(exponent2_, &content);
+  PrependInteger(exponent1_, &content);
+  PrependInteger(prime2_, &content);
+  PrependInteger(prime1_, &content);
+  PrependInteger(private_exponent_, &content);
+  PrependInteger(public_exponent_, &content);
+  PrependInteger(modulus_, &content);
+  PrependInteger(&version, 1, &content);
+  PrependTypeHeaderAndLength(kSequenceTag, content.size(), &content);
+  PrependTypeHeaderAndLength(kOctetStringTag, content.size(), &content);
+
+  // RSA algorithm OID
+  for (size_t i = sizeof(kRsaAlgorithmIdentifier); i > 0; --i)
+    content.push_front(kRsaAlgorithmIdentifier[i - 1]);
+
+  PrependInteger(&version, 1, &content);
+  PrependTypeHeaderAndLength(kSequenceTag, content.size(), &content);
+
+  // Copy everying into the output.
+  output->reserve(content.size());
+  output->assign(content.begin(), content.end());
+
+  return true;
+}
+
+bool PrivateKeyInfoCodec::ExportPublicKeyInfo(std::vector<uint8_t>* output) {
+  // Create a sequence with the modulus (n) and public exponent (e).
+  std::vector<uint8_t> bit_string;
+  if (!ExportPublicKey(&bit_string))
+    return false;
+
+  // Add the sequence as the contents of a bit string.
+  std::list<uint8_t> content;
+  PrependBitString(&bit_string[0], static_cast<int>(bit_string.size()),
+                   &content);
+
+  // Add the RSA algorithm OID.
+  for (size_t i = sizeof(kRsaAlgorithmIdentifier); i > 0; --i)
+    content.push_front(kRsaAlgorithmIdentifier[i - 1]);
+
+  // Finally, wrap everything in a sequence.
+  PrependTypeHeaderAndLength(kSequenceTag, content.size(), &content);
+
+  // Copy everything into the output.
+  output->reserve(content.size());
+  output->assign(content.begin(), content.end());
+
+  return true;
+}
+
+bool PrivateKeyInfoCodec::ExportPublicKey(std::vector<uint8_t>* output) {
+  // Create a sequence with the modulus (n) and public exponent (e).
+  std::list<uint8_t> content;
+  PrependInteger(&public_exponent_[0],
+                 static_cast<int>(public_exponent_.size()),
+                 &content);
+  PrependInteger(&modulus_[0],  static_cast<int>(modulus_.size()), &content);
+  PrependTypeHeaderAndLength(kSequenceTag, content.size(), &content);
+
+  // Copy everything into the output.
+  output->reserve(content.size());
+  output->assign(content.begin(), content.end());
+
+  return true;
+}
+
+bool PrivateKeyInfoCodec::Import(const std::vector<uint8_t>& input) {
+  if (input.empty()) {
+    return false;
+  }
+
+  // Parse the private key info up to the public key values, ignoring
+  // the subsequent private key values.
+  uint8_t* src = const_cast<uint8_t*>(&input.front());
+  uint8_t* end = src + input.size();
+  if (!ReadSequence(&src, end) ||
+      !ReadVersion(&src, end) ||
+      !ReadAlgorithmIdentifier(&src, end) ||
+      !ReadTypeHeaderAndLength(&src, end, kOctetStringTag, NULL) ||
+      !ReadSequence(&src, end) ||
+      !ReadVersion(&src, end) ||
+      !ReadInteger(&src, end, &modulus_))
+    return false;
+
+  int mod_size = modulus_.size();
+  READ_ASSERT(mod_size % 2 == 0);
+  int primes_size = mod_size / 2;
+
+  if (!ReadIntegerWithExpectedSize(&src, end, 4, &public_exponent_) ||
+      !ReadIntegerWithExpectedSize(&src, end, mod_size, &private_exponent_) ||
+      !ReadIntegerWithExpectedSize(&src, end, primes_size, &prime1_) ||
+      !ReadIntegerWithExpectedSize(&src, end, primes_size, &prime2_) ||
+      !ReadIntegerWithExpectedSize(&src, end, primes_size, &exponent1_) ||
+      !ReadIntegerWithExpectedSize(&src, end, primes_size, &exponent2_) ||
+      !ReadIntegerWithExpectedSize(&src, end, primes_size, &coefficient_))
+    return false;
+
+  READ_ASSERT(src == end);
+
+
+  return true;
+}
+
+void PrivateKeyInfoCodec::PrependInteger(const std::vector<uint8_t>& in,
+                                         std::list<uint8_t>* out) {
+  uint8_t* ptr = const_cast<uint8_t*>(&in.front());
+  PrependIntegerImpl(ptr, in.size(), out, big_endian_);
+}
+
+// Helper to prepend an ASN.1 integer.
+void PrivateKeyInfoCodec::PrependInteger(uint8_t* val,
+                                         int num_bytes,
+                                         std::list<uint8_t>* data) {
+  PrependIntegerImpl(val, num_bytes, data, big_endian_);
+}
+
+void PrivateKeyInfoCodec::PrependIntegerImpl(uint8_t* val,
+                                             int num_bytes,
+                                             std::list<uint8_t>* data,
+                                             bool big_endian) {
+ // Reverse input if little-endian.
+ std::vector<uint8_t> tmp;
+ if (!big_endian) {
+   tmp.assign(val, val + num_bytes);
+   std::reverse(tmp.begin(), tmp.end());
+   val = &tmp.front();
+ }
+
+  // ASN.1 integers are unpadded byte arrays, so skip any null padding bytes
+  // from the most-significant end of the integer.
+  int start = 0;
+  while (start < (num_bytes - 1) && val[start] == 0x00) {
+    start++;
+    num_bytes--;
+  }
+  PrependBytes(val, start, num_bytes, data);
+
+  // ASN.1 integers are signed. To encode a positive integer whose sign bit
+  // (the most significant bit) would otherwise be set and make the number
+  // negative, ASN.1 requires a leading null byte to force the integer to be
+  // positive.
+  uint8_t front = data->front();
+  if ((front & 0x80) != 0) {
+    data->push_front(0x00);
+    num_bytes++;
+  }
+
+  PrependTypeHeaderAndLength(kIntegerTag, num_bytes, data);
+}
+
+bool PrivateKeyInfoCodec::ReadInteger(uint8_t** pos,
+                                      uint8_t* end,
+                                      std::vector<uint8_t>* out) {
+  return ReadIntegerImpl(pos, end, out, big_endian_);
+}
+
+bool PrivateKeyInfoCodec::ReadIntegerWithExpectedSize(
+    uint8_t** pos,
+    uint8_t* end,
+    size_t expected_size,
+    std::vector<uint8_t>* out) {
+  std::vector<uint8_t> temp;
+  if (!ReadIntegerImpl(pos, end, &temp, true))  // Big-Endian
+    return false;
+
+  int pad = expected_size - temp.size();
+  int index = 0;
+  if (out->size() == expected_size + 1) {
+    READ_ASSERT(out->front() == 0x00);
+    pad++;
+    index++;
+  } else {
+    READ_ASSERT(out->size() <= expected_size);
+  }
+
+  out->insert(out->end(), pad, 0x00);
+  out->insert(out->end(), temp.begin(), temp.end());
+
+  // Reverse output if little-endian.
+  if (!big_endian_)
+    std::reverse(out->begin(), out->end());
+  return true;
+}
+
+bool PrivateKeyInfoCodec::ReadIntegerImpl(uint8_t** pos,
+                                          uint8_t* end,
+                                          std::vector<uint8_t>* out,
+                                          bool big_endian) {
+  uint32_t length = 0;
+  if (!ReadTypeHeaderAndLength(pos, end, kIntegerTag, &length) || !length)
+    return false;
+
+  // The first byte can be zero to force positiveness. We can ignore this.
+  if (**pos == 0x00) {
+    ++(*pos);
+    --length;
+  }
+
+  if (length)
+    out->insert(out->end(), *pos, (*pos) + length);
+
+  (*pos) += length;
+
+  // Reverse output if little-endian.
+  if (!big_endian)
+    std::reverse(out->begin(), out->end());
+  return true;
+}
+
+void PrivateKeyInfoCodec::PrependBytes(uint8_t* val,
+                                       int start,
+                                       int num_bytes,
+                                       std::list<uint8_t>* data) {
+  while (num_bytes > 0) {
+    --num_bytes;
+    data->push_front(val[start + num_bytes]);
+  }
+}
+
+void PrivateKeyInfoCodec::PrependLength(size_t size, std::list<uint8_t>* data) {
+  // The high bit is used to indicate whether additional octets are needed to
+  // represent the length.
+  if (size < 0x80) {
+    data->push_front(static_cast<uint8_t>(size));
+  } else {
+    uint8_t num_bytes = 0;
+    while (size > 0) {
+      data->push_front(static_cast<uint8_t>(size & 0xFF));
+      size >>= 8;
+      num_bytes++;
+    }
+    CHECK_LE(num_bytes, 4);
+    data->push_front(0x80 | num_bytes);
+  }
+}
+
+void PrivateKeyInfoCodec::PrependTypeHeaderAndLength(
+    uint8_t type,
+    uint32_t length,
+    std::list<uint8_t>* output) {
+  PrependLength(length, output);
+  output->push_front(type);
+}
+
+void PrivateKeyInfoCodec::PrependBitString(uint8_t* val,
+                                           int num_bytes,
+                                           std::list<uint8_t>* output) {
+  // Start with the data.
+  PrependBytes(val, 0, num_bytes, output);
+  // Zero unused bits.
+  output->push_front(0);
+  // Add the length.
+  PrependLength(num_bytes + 1, output);
+  // Finally, add the bit string tag.
+  output->push_front((uint8_t)kBitStringTag);
+}
+
+bool PrivateKeyInfoCodec::ReadLength(uint8_t** pos,
+                                     uint8_t* end,
+                                     uint32_t* result) {
+  READ_ASSERT(*pos < end);
+  int length = 0;
+
+  // If the MSB is not set, the length is just the byte itself.
+  if (!(**pos & 0x80)) {
+    length = **pos;
+    (*pos)++;
+  } else {
+    // Otherwise, the lower 7 indicate the length of the length.
+    int length_of_length = **pos & 0x7F;
+    READ_ASSERT(length_of_length <= 4);
+    (*pos)++;
+    READ_ASSERT(*pos + length_of_length < end);
+
+    length = 0;
+    for (int i = 0; i < length_of_length; ++i) {
+      length <<= 8;
+      length |= **pos;
+      (*pos)++;
+    }
+  }
+
+  READ_ASSERT(*pos + length <= end);
+  if (result) *result = length;
+  return true;
+}
+
+bool PrivateKeyInfoCodec::ReadTypeHeaderAndLength(uint8_t** pos,
+                                                  uint8_t* end,
+                                                  uint8_t expected_tag,
+                                                  uint32_t* length) {
+  READ_ASSERT(*pos < end);
+  READ_ASSERT(**pos == expected_tag);
+  (*pos)++;
+
+  return ReadLength(pos, end, length);
+}
+
+bool PrivateKeyInfoCodec::ReadSequence(uint8_t** pos, uint8_t* end) {
+  return ReadTypeHeaderAndLength(pos, end, kSequenceTag, NULL);
+}
+
+bool PrivateKeyInfoCodec::ReadAlgorithmIdentifier(uint8_t** pos, uint8_t* end) {
+  READ_ASSERT(*pos + sizeof(kRsaAlgorithmIdentifier) < end);
+  READ_ASSERT(memcmp(*pos, kRsaAlgorithmIdentifier,
+                     sizeof(kRsaAlgorithmIdentifier)) == 0);
+  (*pos) += sizeof(kRsaAlgorithmIdentifier);
+  return true;
+}
+
+bool PrivateKeyInfoCodec::ReadVersion(uint8_t** pos, uint8_t* end) {
+  uint32_t length = 0;
+  if (!ReadTypeHeaderAndLength(pos, end, kIntegerTag, &length))
+    return false;
+
+  // The version should be zero.
+  for (uint32_t i = 0; i < length; ++i) {
+    READ_ASSERT(**pos == 0x00);
+    (*pos)++;
+  }
+
+  return true;
+}
+
 }  // namespace
 
 namespace crypto {