Botan  2.8.0
Crypto and TLS for C++11
Public Member Functions | Static Public Member Functions | List of all members
Botan::Getentropy Class Referencefinal

#include <getentropy.h>

Inheritance diagram for Botan::Getentropy:
Botan::Entropy_Source

Public Member Functions

std::string name () const override
 
size_t poll (RandomNumberGenerator &rng) override
 

Static Public Member Functions

static std::unique_ptr< Entropy_Sourcecreate (const std::string &type)
 

Detailed Description

Entropy source using the getentropy(2) system call first introduced in OpenBSD 5.6 and added to Solaris 11.3.

Definition at line 19 of file getentropy.h.

Member Function Documentation

◆ create()

std::unique_ptr< Entropy_Source > Botan::Entropy_Source::create ( const std::string &  type)
staticinherited

Return a new entropy source of a particular type, or null Each entropy source may require substantial resources (eg, a file handle or socket instance), so try to share them among multiple RNGs, or just use the preconfigured global list accessed by Entropy_Sources::global_sources()

Definition at line 63 of file entropy_srcs.cpp.

References BOTAN_UNUSED, Botan::Entropy_Source::name(), and Botan::OS::running_in_privileged_state().

Referenced by Botan::Entropy_Sources::Entropy_Sources().

64  {
65 #if defined(BOTAN_HAS_SYSTEM_RNG)
66  if(name == "system_rng" || name == "win32_cryptoapi")
67  {
68  return std::unique_ptr<Entropy_Source>(new System_RNG_EntropySource);
69  }
70 #endif
71 
72 #if defined(BOTAN_HAS_ENTROPY_SRC_RDRAND)
73  if(name == "rdrand")
74  {
75  return std::unique_ptr<Entropy_Source>(new Intel_Rdrand);
76  }
77 #endif
78 
79 #if defined(BOTAN_HAS_ENTROPY_SRC_RDSEED)
80  if(name == "rdseed")
81  {
82  return std::unique_ptr<Entropy_Source>(new Intel_Rdseed);
83  }
84 #endif
85 
86 #if defined(BOTAN_HAS_ENTROPY_SRC_GETENTROPY)
87  if(name == "getentropy")
88  {
89  return std::unique_ptr<Entropy_Source>(new Getentropy);
90  }
91 #endif
92 
93 #if defined(BOTAN_HAS_ENTROPY_SRC_DEV_RANDOM)
94  if(name == "dev_random")
95  {
96  return std::unique_ptr<Entropy_Source>(new Device_EntropySource(BOTAN_SYSTEM_RNG_POLL_DEVICES));
97  }
98 #endif
99 
100 #if defined(BOTAN_HAS_ENTROPY_SRC_PROC_WALKER)
101  if(name == "proc_walk" && OS::running_in_privileged_state() == false)
102  {
103  const std::string root_dir = BOTAN_ENTROPY_PROC_FS_PATH;
104  if(!root_dir.empty())
105  return std::unique_ptr<Entropy_Source>(new ProcWalking_EntropySource(root_dir));
106  }
107 #endif
108 
109 #if defined(BOTAN_HAS_ENTROPY_SRC_WIN32)
110  if(name == "system_stats")
111  {
112  return std::unique_ptr<Entropy_Source>(new Win32_EntropySource);
113  }
114 #endif
115 
117  return std::unique_ptr<Entropy_Source>();
118  }
virtual std::string name() const =0
bool running_in_privileged_state()
Definition: os_utils.cpp:83
#define BOTAN_UNUSED(...)
Definition: assert.h:142

◆ name()

std::string Botan::Getentropy::name ( ) const
inlineoverridevirtual
Returns
name identifying this entropy source

Implements Botan::Entropy_Source.

Definition at line 22 of file getentropy.h.

22 { return "getentropy"; }

◆ poll()

size_t Botan::Getentropy::poll ( RandomNumberGenerator rng)
overridevirtual

Gather 256 bytes entropy from getentropy(2). Note that maximum buffer size is limited to 256 bytes. On OpenBSD this does neither block nor fail.

Implements Botan::Entropy_Source.

Definition at line 23 of file getentropy.cpp.

References Botan::RandomNumberGenerator::add_entropy().

24  {
25  secure_vector<uint8_t> buf(256);
26 
27  if(::getentropy(buf.data(), buf.size()) == 0)
28  {
29  rng.add_entropy(buf.data(), buf.size());
30  return buf.size() * 8;
31  }
32 
33  return 0;
34  }

The documentation for this class was generated from the following files: