Botan  2.19.1
Crypto and TLS for C++11
Functions
ffi_rng.cpp File Reference
#include <botan/ffi.h>
#include <botan/internal/ffi_util.h>
#include <botan/internal/ffi_rng.h>
#include <botan/system_rng.h>
#include <botan/auto_rng.h>
#include <functional>

Go to the source code of this file.

Functions

int botan_rng_add_entropy (botan_rng_t rng, const uint8_t *input, size_t len)
 
int botan_rng_destroy (botan_rng_t rng)
 
int botan_rng_get (botan_rng_t rng, uint8_t *out, size_t out_len)
 
int botan_rng_init (botan_rng_t *rng_out, const char *rng_type)
 
int botan_rng_init_custom (botan_rng_t *rng_out, const char *rng_name, void *context, int(*get_cb)(void *context, uint8_t *out, size_t out_len), int(*add_entropy_cb)(void *context, const uint8_t input[], size_t length), void(*destroy_cb)(void *context))
 
int botan_rng_reseed (botan_rng_t rng, size_t bits)
 
int botan_rng_reseed_from_rng (botan_rng_t rng, botan_rng_t source_rng, size_t bits)
 

Function Documentation

int botan_rng_add_entropy ( botan_rng_t  rng,
const uint8_t *  entropy,
size_t  entropy_len 
)

Add some seed material to a random number generator

Parameters
rngrng object
entropythe data to add
entropy_lenlength of entropy buffer
Returns
0 on success, a negative value on failure

Definition at line 173 of file ffi_rng.cpp.

References Botan::RandomNumberGenerator::add_entropy(), and BOTAN_FFI_DO.

174  {
175  return BOTAN_FFI_DO(Botan::RandomNumberGenerator, rng, r, { r.add_entropy(input, len); });
176  }
virtual void add_entropy(const uint8_t input[], size_t length)=0
#define BOTAN_FFI_DO(T, obj, param, block)
Definition: ffi_util.h:92
int botan_rng_destroy ( botan_rng_t  rng)

Frees all resources of the random number generator object

Parameters
rngrng object
Returns
0 if success, error if invalid object handle

Definition at line 158 of file ffi_rng.cpp.

References BOTAN_FFI_CHECKED_DELETE.

159  {
160  return BOTAN_FFI_CHECKED_DELETE(rng);
161  }
#define BOTAN_FFI_CHECKED_DELETE(o)
Definition: ffi_util.h:129
int botan_rng_get ( botan_rng_t  rng,
uint8_t *  out,
size_t  out_len 
)

Get random bytes from a random number generator

Parameters
rngrng object
outoutput buffer of size out_len
out_lennumber of requested bytes
Returns
0 on success, negative on failure

Definition at line 163 of file ffi_rng.cpp.

References BOTAN_FFI_DO, and Botan::RandomNumberGenerator::randomize().

164  {
165  return BOTAN_FFI_DO(Botan::RandomNumberGenerator, rng, r, { r.randomize(out, out_len); });
166  }
virtual void randomize(uint8_t output[], size_t length)=0
#define BOTAN_FFI_DO(T, obj, param, block)
Definition: ffi_util.h:92
int botan_rng_init ( botan_rng_t rng,
const char *  rng_type 
)

Initialize a random number generator object

Parameters
rngrng object
rng_typetype of the rng, possible values: "system": system RNG "user": userspace RNG "user-threadsafe": userspace RNG, with internal locking "rdrand": directly read RDRAND Set rng_type to null to let the library choose some default.

Definition at line 24 of file ffi_rng.cpp.

References Botan::Processor_RNG::available(), BOTAN_FFI_ERROR_NOT_IMPLEMENTED, BOTAN_FFI_ERROR_NULL_POINTER, BOTAN_FFI_SUCCESS, and Botan_FFI::ffi_guard_thunk().

25  {
26  return ffi_guard_thunk(__func__, [=]() -> int {
27  if(rng_out == nullptr)
29 
30  const std::string rng_type_s(rng_type ? rng_type : "system");
31 
32  std::unique_ptr<Botan::RandomNumberGenerator> rng;
33 
34  if(rng_type_s == "system")
35  {
36  rng.reset(new Botan::System_RNG);
37  }
38  else if(rng_type_s == "user" || rng_type_s == "user-threadsafe")
39  {
40  rng.reset(new Botan::AutoSeeded_RNG);
41  }
42  else if(rng_type_s == "null")
43  {
44  rng.reset(new Botan::Null_RNG);
45  }
46 #if defined(BOTAN_HAS_PROCESSOR_RNG)
47  else if((rng_type_s == "rdrand" || rng_type_s == "hwrng") && Botan::Processor_RNG::available())
48  {
49  rng.reset(new Botan::Processor_RNG);
50  }
51 #endif
52 
53  if(!rng)
54  {
56  }
57 
58  *rng_out = new botan_rng_struct(rng.release());
59  return BOTAN_FFI_SUCCESS;
60  });
61  }
int ffi_guard_thunk(const char *func_name, std::function< int()> thunk)
Definition: ffi.cpp:89
static bool available()
int botan_rng_init_custom ( botan_rng_t rng_out,
const char *  rng_name,
void *  context,
int(*)(void *context, uint8_t *out, size_t out_len)  get_cb,
int(*)(void *context, const uint8_t input[], size_t length)  add_entropy_cb,
void(*)(void *context)  destroy_cb 
)

Initialize a custom random number generator from a set of callback functions

Parameters
rngrng object
rng_namename of the rng
contextAn application-specific context passed to the callback functions
get_cbCallback for getting random bytes from the rng, return 0 for success
add_entry_cbCallback for adding entropy to the rng, return 0 for success, may be NULL
destroy_cbCallback called when rng is destroyed, may be NULL

Definition at line 63 of file ffi_rng.cpp.

References BOTAN_FFI_ERROR_NULL_POINTER, BOTAN_FFI_SUCCESS, Botan_FFI::ffi_guard_thunk(), m_context, m_name, name, and Botan::ASN1::to_string().

67 {
68 return ffi_guard_thunk(__func__,[=]() -> int {
69  if(rng_out == nullptr)
71 
72  if(rng_name == nullptr)
74 
75  if(get_cb == nullptr)
77 
78  class Custom_RNG : public Botan::RandomNumberGenerator
79  {
80  public:
81  Custom_RNG(const std::string& name, void* context,
82  int(* get_cb)(void* context, uint8_t* out, size_t out_len),
83  int(* add_entropy_cb)(void* context, const uint8_t input[], size_t length),
84  void(* destroy_cb)(void* context)) :
85  m_name(name)
86  {
87  m_context = context;
88  m_get_cb = get_cb;
89  m_add_entropy_cb = add_entropy_cb;
90  m_destroy_cb = destroy_cb;
91  }
92 
93  ~Custom_RNG()
94  {
95  if(m_destroy_cb)
96  {
97  m_destroy_cb(m_context);
98  }
99  }
100 
101  void randomize(uint8_t output[], size_t length) override
102  {
103  int rc = m_get_cb(m_context, output, length);
104  if(rc)
105  {
106  throw Botan::Invalid_State("Failed to get random from C callback, rc=" + std::to_string(rc));
107  }
108  }
109 
110  bool accepts_input() const override
111  {
112  return m_add_entropy_cb != nullptr;
113  }
114 
115  void add_entropy(const uint8_t input[], size_t length) override
116  {
117  if(m_add_entropy_cb == nullptr)
118  {
119  return;
120  }
121 
122  int rc = m_add_entropy_cb(m_context, input, length);
123  if(rc)
124  {
125  throw Botan::Invalid_State("Failed to add entropy via C callback, rc=" + std::to_string(rc));
126  }
127  }
128 
129  std::string name() const override
130  {
131  return m_name;
132  }
133 
134  void clear() override
135  {
136  }
137 
138  bool is_seeded() const override
139  {
140  return true;
141  }
142 
143  private:
144  std::string m_name;
145  void* m_context;
146  std::function<int(void* context, uint8_t* out, size_t out_len)> m_get_cb;
147  std::function<int(void* context, const uint8_t input[], size_t length)> m_add_entropy_cb;
148  std::function<void(void* context)> m_destroy_cb;
149  };
150 
151  std::unique_ptr<Botan::RandomNumberGenerator> rng(new Custom_RNG(rng_name, context, get_cb, add_entropy_cb, destroy_cb));
152 
153  *rng_out = new botan_rng_struct(rng.release());
154  return BOTAN_FFI_SUCCESS;
155  });
156 }
int ffi_guard_thunk(const char *func_name, std::function< int()> thunk)
Definition: ffi.cpp:89
virtual void add_entropy(const uint8_t input[], size_t length)=0
std::string m_name
virtual void randomize(uint8_t output[], size_t length)=0
T m_context
std::string to_string(const BER_Object &obj)
Definition: asn1_obj.cpp:213
std::string name
virtual std::string name() const =0
virtual bool accepts_input() const =0
virtual bool is_seeded() const =0
int botan_rng_reseed ( botan_rng_t  rng,
size_t  bits 
)

Reseed a random number generator Uses the System_RNG as a seed generator.

Parameters
rngrng object
bitsnumber of bits to to reseed with
Returns
0 on success, a negative value on failure

Definition at line 168 of file ffi_rng.cpp.

References BOTAN_FFI_DO, Botan::RandomNumberGenerator::reseed_from_rng(), and Botan::system_rng().

169  {
171  }
RandomNumberGenerator & system_rng()
Definition: system_rng.cpp:283
virtual void reseed_from_rng(RandomNumberGenerator &rng, size_t poll_bits=BOTAN_RNG_RESEED_POLL_BITS)
Definition: rng.cpp:59
#define BOTAN_FFI_DO(T, obj, param, block)
Definition: ffi_util.h:92
int botan_rng_reseed_from_rng ( botan_rng_t  rng,
botan_rng_t  source_rng,
size_t  bits 
)

Reseed a random number generator

Parameters
rngrng object
source_rngthe rng that will be read from
bitsnumber of bits to to reseed with
Returns
0 on success, a negative value on failure

Definition at line 178 of file ffi_rng.cpp.

References BOTAN_FFI_DO, Botan::RandomNumberGenerator::reseed_from_rng(), and Botan_FFI::safe_get().

179  {
180  return BOTAN_FFI_DO(Botan::RandomNumberGenerator, rng, r, { r.reseed_from_rng(safe_get(source_rng), bits); });
181  }
T & safe_get(botan_struct< T, M > *p)
Definition: ffi_util.h:61
virtual void reseed_from_rng(RandomNumberGenerator &rng, size_t poll_bits=BOTAN_RNG_RESEED_POLL_BITS)
Definition: rng.cpp:59
#define BOTAN_FFI_DO(T, obj, param, block)
Definition: ffi_util.h:92