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      1 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
      2 // Use of this source code is governed by a BSD-style license that can be
      3 // found in the LICENSE file.
      4 
      5 #ifndef CRYPTO_SIGNATURE_VERIFIER_H_
      6 #define CRYPTO_SIGNATURE_VERIFIER_H_
      7 
      8 #include <stdint.h>
      9 
     10 #include <vector>
     11 
     12 #include "build/build_config.h"
     13 #include "crypto/crypto_export.h"
     14 
     15 #if defined(USE_OPENSSL)
     16 typedef struct env_md_st EVP_MD;
     17 typedef struct evp_pkey_ctx_st EVP_PKEY_CTX;
     18 #else
     19 typedef struct HASHContextStr HASHContext;
     20 typedef struct SECKEYPublicKeyStr SECKEYPublicKey;
     21 typedef struct VFYContextStr VFYContext;
     22 #endif
     23 
     24 namespace crypto {
     25 
     26 // The SignatureVerifier class verifies a signature using a bare public key
     27 // (as opposed to a certificate).
     28 class CRYPTO_EXPORT SignatureVerifier {
     29  public:
     30   // The set of supported hash functions. Extend as required.
     31   enum HashAlgorithm {
     32     SHA1,
     33     SHA256,
     34   };
     35 
     36   // The set of supported signature algorithms. Extend as required.
     37   enum SignatureAlgorithm {
     38     RSA_PKCS1_SHA1,
     39     RSA_PKCS1_SHA256,
     40     ECDSA_SHA256,
     41   };
     42 
     43   SignatureVerifier();
     44   ~SignatureVerifier();
     45 
     46   // Streaming interface:
     47 
     48   // Initiates a signature verification operation.  This should be followed
     49   // by one or more VerifyUpdate calls and a VerifyFinal call.
     50   // NOTE: for RSA-PSS signatures, use VerifyInitRSAPSS instead.
     51   //
     52   // The signature is encoded according to the signature algorithm.
     53   //
     54   // The public key is specified as a DER encoded ASN.1 SubjectPublicKeyInfo
     55   // structure, which contains not only the public key but also its type
     56   // (algorithm):
     57   //   SubjectPublicKeyInfo  ::=  SEQUENCE  {
     58   //       algorithm            AlgorithmIdentifier,
     59   //       subjectPublicKey     BIT STRING  }
     60   bool VerifyInit(SignatureAlgorithm signature_algorithm,
     61                   const uint8_t* signature,
     62                   int signature_len,
     63                   const uint8_t* public_key_info,
     64                   int public_key_info_len);
     65 
     66   // Initiates a RSA-PSS signature verification operation.  This should be
     67   // followed by one or more VerifyUpdate calls and a VerifyFinal call.
     68   //
     69   // The RSA-PSS signature algorithm parameters are specified with the
     70   // |hash_alg|, |mask_hash_alg|, and |salt_len| arguments.
     71   //
     72   // An RSA-PSS signature is a nonnegative integer encoded as a byte string
     73   // (of the same length as the RSA modulus) in big-endian byte order. It
     74   // must not be further encoded in an ASN.1 BIT STRING.
     75   //
     76   // The public key is specified as a DER encoded ASN.1 SubjectPublicKeyInfo
     77   // structure, which contains not only the public key but also its type
     78   // (algorithm):
     79   //   SubjectPublicKeyInfo  ::=  SEQUENCE  {
     80   //       algorithm            AlgorithmIdentifier,
     81   //       subjectPublicKey     BIT STRING  }
     82   bool VerifyInitRSAPSS(HashAlgorithm hash_alg,
     83                         HashAlgorithm mask_hash_alg,
     84                         int salt_len,
     85                         const uint8_t* signature,
     86                         int signature_len,
     87                         const uint8_t* public_key_info,
     88                         int public_key_info_len);
     89 
     90   // Feeds a piece of the data to the signature verifier.
     91   void VerifyUpdate(const uint8_t* data_part, int data_part_len);
     92 
     93   // Concludes a signature verification operation.  Returns true if the
     94   // signature is valid.  Returns false if the signature is invalid or an
     95   // error occurred.
     96   bool VerifyFinal();
     97 
     98  private:
     99 #if defined(USE_OPENSSL)
    100   bool CommonInit(int pkey_type,
    101                   const EVP_MD* digest,
    102                   const uint8_t* signature,
    103                   int signature_len,
    104                   const uint8_t* public_key_info,
    105                   int public_key_info_len,
    106                   EVP_PKEY_CTX** pkey_ctx);
    107 #else
    108   static SECKEYPublicKey* DecodePublicKeyInfo(const uint8_t* public_key_info,
    109                                               int public_key_info_len);
    110 #endif
    111 
    112   void Reset();
    113 
    114   std::vector<uint8_t> signature_;
    115 
    116 #if defined(USE_OPENSSL)
    117   struct VerifyContext;
    118   VerifyContext* verify_context_;
    119 #else
    120   // Used for all signature types except RSA-PSS.
    121   VFYContext* vfy_context_;
    122 
    123   // Used for RSA-PSS signatures.
    124   HashAlgorithm hash_alg_;
    125   HashAlgorithm mask_hash_alg_;
    126   unsigned int salt_len_;
    127   SECKEYPublicKey* public_key_;
    128   HASHContext* hash_context_;
    129 #endif
    130 };
    131 
    132 }  // namespace crypto
    133 
    134 #endif  // CRYPTO_SIGNATURE_VERIFIER_H_
    135