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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 NET_BASE_HASH_VALUE_H_
      6 #define NET_BASE_HASH_VALUE_H_
      7 
      8 #include <string.h>
      9 
     10 #include <string>
     11 #include <vector>
     12 
     13 #include "base/basictypes.h"
     14 #include "base/strings/string_piece.h"
     15 #include "build/build_config.h"
     16 #include "net/base/net_export.h"
     17 
     18 namespace net {
     19 
     20 struct NET_EXPORT SHA1HashValue {
     21   bool Equals(const SHA1HashValue& other) const;
     22 
     23   unsigned char data[20];
     24 };
     25 
     26 struct NET_EXPORT SHA256HashValue {
     27   bool Equals(const SHA256HashValue& other) const;
     28 
     29   unsigned char data[32];
     30 };
     31 
     32 enum HashValueTag {
     33   HASH_VALUE_SHA1,
     34   HASH_VALUE_SHA256,
     35 
     36   // This must always be last.
     37   HASH_VALUE_TAGS_COUNT
     38 };
     39 
     40 class NET_EXPORT HashValue {
     41  public:
     42   explicit HashValue(HashValueTag tag) : tag(tag) {}
     43   HashValue() : tag(HASH_VALUE_SHA1) {}
     44 
     45   // Check for equality of hash values
     46   // This function may have VARIABLE timing which leaks information
     47   // about its inputs.  For example it may exit early once a
     48   // nonequal character is discovered.  Thus, for security reasons
     49   // this function MUST NOT be used with secret values (such as
     50   // password hashes, MAC tags, etc.)
     51   bool Equals(const HashValue& other) const;
     52 
     53   // Serializes/Deserializes hashes in the form of
     54   // <hash-name>"/"<base64-hash-value>
     55   // (eg: "sha1/...")
     56   // This format may be persisted to permanent storage, so
     57   // care should be taken before changing the serialization.
     58   //
     59   // This format is used for:
     60   //   - net_internals display/setting public-key pins
     61   //   - logging public-key pins
     62   //   - serializing public-key pins
     63 
     64   // Deserializes a HashValue from a string. On error, returns
     65   // false and MAY change the contents of HashValue to contain invalid data.
     66   bool FromString(const base::StringPiece input);
     67 
     68   // Serializes the HashValue to a string. If an invalid HashValue
     69   // is supplied (eg: an unknown hash tag), returns "unknown"/<base64>
     70   std::string ToString() const;
     71 
     72   size_t size() const;
     73   unsigned char* data();
     74   const unsigned char* data() const;
     75 
     76   HashValueTag tag;
     77 
     78  private:
     79   union {
     80     SHA1HashValue sha1;
     81     SHA256HashValue sha256;
     82   } fingerprint;
     83 };
     84 
     85 typedef std::vector<HashValue> HashValueVector;
     86 
     87 
     88 class SHA1HashValueLessThan {
     89  public:
     90   bool operator()(const SHA1HashValue& lhs,
     91                   const SHA1HashValue& rhs) const {
     92     return memcmp(lhs.data, rhs.data, sizeof(lhs.data)) < 0;
     93   }
     94 };
     95 
     96 class SHA256HashValueLessThan {
     97  public:
     98   bool operator()(const SHA256HashValue& lhs,
     99                   const SHA256HashValue& rhs) const {
    100     return memcmp(lhs.data, rhs.data, sizeof(lhs.data)) < 0;
    101   }
    102 };
    103 
    104 class HashValuesEqual {
    105   public:
    106   explicit HashValuesEqual(const HashValue& fingerprint) :
    107       fingerprint_(fingerprint) {}
    108 
    109   bool operator()(const HashValue& other) const {
    110     return fingerprint_.Equals(other);
    111   }
    112 
    113   const HashValue& fingerprint_;
    114 };
    115 
    116 
    117 // IsSHA1HashInSortedArray returns true iff |hash| is in |array|, a sorted
    118 // array of SHA1 hashes.
    119 bool IsSHA1HashInSortedArray(const SHA1HashValue& hash,
    120                              const uint8* array,
    121                              size_t array_byte_len);
    122 
    123 }  // namespace net
    124 
    125 #endif  // NET_BASE_HASH_VALUE_H_
    126