Botan 2.19.1
Crypto and TLS for C&
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 107 of file entropy_srcs.cpp.

108 {
109#if defined(BOTAN_HAS_SYSTEM_RNG)
110 if(name == "system_rng" || name == "win32_cryptoapi")
111 {
112 return std::unique_ptr<Entropy_Source>(new System_RNG_EntropySource);
113 }
114#endif
115
116#if defined(BOTAN_HAS_PROCESSOR_RNG)
117 if(name == "hwrng" || name == "rdrand" || name == "p9_darn")
118 {
120 {
121 return std::unique_ptr<Entropy_Source>(new Processor_RNG_EntropySource);
122 }
123 }
124#endif
125
126#if defined(BOTAN_HAS_ENTROPY_SRC_RDSEED)
127 if(name == "rdseed")
128 {
129 return std::unique_ptr<Entropy_Source>(new Intel_Rdseed);
130 }
131#endif
132
133#if defined(BOTAN_HAS_ENTROPY_SRC_GETENTROPY)
134 if(name == "getentropy")
135 {
136 return std::unique_ptr<Entropy_Source>(new Getentropy);
137 }
138#endif
139
140#if defined(BOTAN_HAS_ENTROPY_SRC_DEV_RANDOM)
141 if(name == "dev_random")
142 {
143 return std::unique_ptr<Entropy_Source>(new Device_EntropySource(BOTAN_SYSTEM_RNG_POLL_DEVICES));
144 }
145#endif
146
147#if defined(BOTAN_HAS_ENTROPY_SRC_PROC_WALKER)
148 if(name == "proc_walk" && OS::running_in_privileged_state() == false)
149 {
150 const std::string root_dir = BOTAN_ENTROPY_PROC_FS_PATH;
151 if(!root_dir.empty())
152 return std::unique_ptr<Entropy_Source>(new ProcWalking_EntropySource(root_dir));
153 }
154#endif
155
156#if defined(BOTAN_HAS_ENTROPY_SRC_WIN32)
157 if(name == "system_stats")
158 {
159 return std::unique_ptr<Entropy_Source>(new Win32_EntropySource);
160 }
161#endif
162
164 return std::unique_ptr<Entropy_Source>();
165 }
#define BOTAN_UNUSED(...)
Definition: assert.h:142
virtual std::string name() const =0
static bool available()
bool running_in_privileged_state()
Definition: os_utils.cpp:143

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

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

◆ 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 27 of file getentropy.cpp.

28 {
29 secure_vector<uint8_t> buf(256);
30
31 if(::getentropy(buf.data(), buf.size()) == 0)
32 {
33 rng.add_entropy(buf.data(), buf.size());
34 return buf.size() * 8;
35 }
36
37 return 0;
38 }

References Botan::RandomNumberGenerator::add_entropy().


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