Refactor ASN1 parsing/serializationg

base/crypto/rsa_private_key.h

Index: base/crypto/rsa_private_key.h
diff --git a/base/crypto/rsa_private_key.h b/base/crypto/rsa_private_key.h
index a6b0e20319242a1655cd6dd7bd803feab5741f1d..3f07188c8af900397704780bcc00cf752c7157ce 100644
--- a/base/crypto/rsa_private_key.h
+++ b/base/crypto/rsa_private_key.h
@@ -17,12 +17,139 @@
 #include <wincrypt.h>
 #endif
 
+#include <list>
 #include <vector>
 
 #include "base/basictypes.h"
 
 namespace base {
 
+// 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 kRsaAlgorithmIdentifier[];
+
+  // ASN.1 tags for some types we use.
+  static const uint8 kBitStringTag = 0x03;
+  static const uint8 kIntegerTag = 0x02;
+  static const uint8 kNullTag = 0x05;
+  static const uint8 kOctetStringTag = 0x04;
+  static const uint8 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) : big_endian_(big_endian) {}
+
+  // Exports the contents of the integer components to the ASN.1 DER encoding
+  // of the PrivateKeyInfo structure to |output|.
+  bool Export(std::vector<uint8>* 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>* output);
+
+  // Parses the ASN.1 DER encoding of the PrivateKeyInfo structure in |input|
+  // and populates the integer components with |big_endian_| byte-significance.
+  bool Import(const std::vector<uint8>& input);
+
+  // Accessors to the contents of the integer components of the PrivateKeyInfo
+  // structure.
+  std::vector<uint8>* modulus() { return &modulus_; };
+  std::vector<uint8>* public_exponent() { return &public_exponent_; };
+  std::vector<uint8>* private_exponent() { return &private_exponent_; };
+  std::vector<uint8>* prime1() { return &prime1_; };
+  std::vector<uint8>* prime2() { return &prime2_; };
+  std::vector<uint8>* exponent1() { return &exponent1_; };
+  std::vector<uint8>* exponent2() { return &exponent2_; };
+  std::vector<uint8>* coefficient() { return &coefficient_; };
+
+ private:
+  // Utility wrappers for PrependIntegerImpl that use the class's |big_endian_|
+  // value.
+  void PrependInteger(const std::vector<uint8>& in, std::list<uint8>* out);
+  void PrependInteger(uint8* val, int num_bytes, std::list<uint8>* 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* val,
+                          int num_bytes,
+                          std::list<uint8>* data,
+                          bool big_endian);
+
+  // Utility wrappers for ReadIntegerImpl that use the class's |big_endian_|
+  // value.
+  bool ReadInteger(uint8** pos, uint8* end, std::vector<uint8>* out);
+  bool ReadIntegerWithExpectedSize(uint8** pos,
+                                   uint8* end,
+                                   size_t expected_size,
+                                   std::vector<uint8>* out);
+
+  // Reads an ASN.1 integer from |pos|, and stores the result into |out| with
+  // |big_endian| byte-significance.
+  bool ReadIntegerImpl(uint8** pos,
+                       uint8* end,
+                       std::vector<uint8>* out, 
+                       bool big_endian);
+  
+  // Prepends the integer stored in |val|, starting a index |start|, for
+  // |num_bytes| bytes onto |data|.
+  void PrependBytes(uint8* val,
+                    int start,
+                    int num_bytes,
+                    std::list<uint8>* data);
+
+  // Helper to prepend an ASN.1 length field.
+  void PrependLength(size_t size, std::list<uint8>* data);
+
+  // Helper to prepend an ASN.1 type header.
+  void PrependTypeHeaderAndLength(uint8 type,
+                                  uint32 length,
+                                  std::list<uint8>* output);
+
+  // Helper to prepend an ASN.1 bit string
+  void PrependBitString(uint8* val, int num_bytes, std::list<uint8>* output);
+
+  // Read an ASN.1 length field. This also checks that the length does not
+  // extend beyond |end|.
+  bool ReadLength(uint8** pos, uint8* end, uint32* result);
+
+  // Read an ASN.1 type header and its length.
+  bool ReadTypeHeaderAndLength(uint8** pos,
+                               uint8* end,
+                               uint8 expected_tag,
+                               uint32* 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** pos, uint8* end);
+
+  // Read the RSA AlgorithmIdentifier.
+  bool ReadAlgorithmIdentifier(uint8** pos, uint8* end);
+
+  // Read one of the two version fields in PrivateKeyInfo.
+  bool ReadVersion(uint8** pos, uint8* end);
+
+  // The byte-significance of the stored components (modulus, etc..).
+  bool big_endian_;
+
+  // Component integers of the PrivateKeyInfo
+  std::vector<uint8> modulus_;
+  std::vector<uint8> public_exponent_;
+  std::vector<uint8> private_exponent_;
+  std::vector<uint8> prime1_;
+  std::vector<uint8> prime2_;
+  std::vector<uint8> exponent1_;
+  std::vector<uint8> exponent2_;
+  std::vector<uint8> coefficient_;
+
+  DISALLOW_COPY_AND_ASSIGN(PrivateKeyInfoCodec);
+};
+
 // Encapsulates an RSA private key. Can be used to generate new keys, export
 // keys to other formats, or to extract a public key.
 class RSAPrivateKey {