security/ct/CTUtils.h

   1 /* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
   2 /* vim: set ts=8 sts=2 et sw=2 tw=80: */
   3 /* This Source Code Form is subject to the terms of the Mozilla Public
   4  * License, v. 2.0. If a copy of the MPL was not distributed with this
   5  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
   6
   7 #ifndef CTUtils_h
   8 #define CTUtils_h
   9
  10 #include <memory>
  11
  12 #include "cryptohi.h"
  13 #include "keyhi.h"
  14 #include "keythi.h"
  15 #include "pk11pub.h"
  16 #include "mozpkix/Input.h"
  17 #include "mozpkix/Result.h"
  18
  19 #define MOZILLA_CT_ARRAY_LENGTH(x) (sizeof(x) / sizeof((x)[0]))
  20
  21 struct DeleteHelper {
  22   void operator()(CERTSubjectPublicKeyInfo* value) {
  23     SECKEY_DestroySubjectPublicKeyInfo(value);
  24   }
  25   void operator()(PK11Context* value) { PK11_DestroyContext(value, true); }
  26   void operator()(PK11SlotInfo* value) { PK11_FreeSlot(value); }
  27   void operator()(SECKEYPublicKey* value) { SECKEY_DestroyPublicKey(value); }
  28   void operator()(SECItem* value) { SECITEM_FreeItem(value, true); }
  29 };
  30
  31 template <class T>
  32 struct MaybeDeleteHelper {
  33   void operator()(T* ptr) {
  34     if (ptr) {
  35       DeleteHelper del;
  36       del(ptr);
  37     }
  38   }
  39 };
  40
  41 typedef std::unique_ptr<CERTSubjectPublicKeyInfo,
  42                         MaybeDeleteHelper<CERTSubjectPublicKeyInfo>>
  43     UniqueCERTSubjectPublicKeyInfo;
  44 typedef std::unique_ptr<PK11Context, MaybeDeleteHelper<PK11Context>>
  45     UniquePK11Context;
  46 typedef std::unique_ptr<PK11SlotInfo, MaybeDeleteHelper<PK11SlotInfo>>
  47     UniquePK11SlotInfo;
  48 typedef std::unique_ptr<SECKEYPublicKey, MaybeDeleteHelper<SECKEYPublicKey>>
  49     UniqueSECKEYPublicKey;
  50 typedef std::unique_ptr<SECItem, MaybeDeleteHelper<SECItem>> UniqueSECItem;
  51
  52 namespace mozilla {
  53 namespace ct {
  54
  55 // Reads a TLS-encoded variable length unsigned integer from |in|.
  56 // The integer is expected to be in big-endian order, which is used by TLS.
  57 // Note: does not check if the output parameter overflows while reading.
  58 // |length| indicates the size (in bytes) of the serialized integer.
  59 inline static pkix::Result UncheckedReadUint(size_t length, pkix::Reader& in,
  60                                              uint64_t& out) {
  61   uint64_t result = 0;
  62   for (size_t i = 0; i < length; ++i) {
  63     uint8_t value;
  64     pkix::Result rv = in.Read(value);
  65     if (rv != pkix::Success) {
  66       return rv;
  67     }
  68     result = (result << 8) | value;
  69   }
  70   out = result;
  71   return pkix::Success;
  72 }
  73
  74 // Performs overflow sanity checks and calls UncheckedReadUint.
  75 template <size_t length, typename T>
  76 pkix::Result ReadUint(pkix::Reader& in, T& out) {
  77   uint64_t value;
  78   static_assert(std::is_unsigned<T>::value, "T must be unsigned");
  79   static_assert(length <= 8, "At most 8 byte integers can be read");
  80   static_assert(sizeof(T) >= length, "T must be able to hold <length> bytes");
  81   pkix::Result rv = UncheckedReadUint(length, in, value);
  82   if (rv != pkix::Success) {
  83     return rv;
  84   }
  85   out = static_cast<T>(value);
  86   return pkix::Success;
  87 }
  88
  89 // Reads |length| bytes from |in|.
  90 static inline pkix::Result ReadFixedBytes(size_t length, pkix::Reader& in,
  91                                           pkix::Input& out) {
  92   return in.Skip(length, out);
  93 }
  94
  95 // Reads a length-prefixed variable amount of bytes from |in|, updating |out|
  96 // on success. |prefixLength| indicates the number of bytes needed to represent
  97 // the length.
  98 template <size_t prefixLength>
  99 pkix::Result ReadVariableBytes(pkix::Reader& in, pkix::Input& out) {
 100   size_t length;
 101   pkix::Result rv = ReadUint<prefixLength>(in, length);
 102   if (rv != pkix::Success) {
 103     return rv;
 104   }
 105   return ReadFixedBytes(length, in, out);
 106 }
 107
 108 }  // namespace ct
 109 }  // namespace mozilla
 110
 111 #endif  // CTUtils_h