5079590438

Committed 25 May 2023 12:28PM UTC coverage: 92.228% (+0.5%) from 91.723%

Build # 5079590438

Build Type

Pull #3502

github

Pull Request Pull Request #3502: Apply clang-format to the codebase

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94.74

/src/lib/rng/processor_rng/processor_rng.cpp

/*
* (C) 2016,2019,2020 Jack Lloyd
*
* Botan is released under the Simplified BSD License (see license.txt)
*/

#include <botan/processor_rng.h>

#include <botan/internal/cpuid.h>
#include <botan/internal/loadstor.h>

#if defined(BOTAN_TARGET_CPU_IS_X86_FAMILY) && !defined(BOTAN_USE_GCC_INLINE_ASM)
   #include <immintrin.h>
#endif

namespace Botan {

namespace {

#if defined(BOTAN_TARGET_CPU_IS_X86_FAMILY)
/*
   * According to Intel, RDRAND is guaranteed to generate a random
   * number within 10 retries on a working CPU
   */
const size_t HWRNG_RETRIES = 10;

#elif defined(BOTAN_TARGET_CPU_IS_PPC_FAMILY)
/**
    * PowerISA 3.0 p.78:
    *    When the error value is obtained, software is expected to repeat the
    *    operation. [...] The recommended number of attempts may be
    *    implementation specific. In the absence of other guidance, ten attempts
    *    should be adequate.
    */
const size_t HWRNG_RETRIES = 10;

#else
/*
   * Lacking specific guidance we give the CPU quite a bit of leeway
   */
const size_t HWRNG_RETRIES = 512;
#endif

#if defined(BOTAN_TARGET_ARCH_IS_X86_32)
typedef uint32_t hwrng_output;
#else
typedef uint64_t hwrng_output;
#endif

hwrng_output read_hwrng(bool& success) {
   hwrng_output output = 0;
   success = false;

#if defined(BOTAN_TARGET_CPU_IS_X86_FAMILY)
   int cf = 0;
   #if defined(BOTAN_USE_GCC_INLINE_ASM)
   // same asm seq works for 32 and 64 bit
   asm volatile("rdrand %0; adcl $0,%1" : "=r"(output), "=r"(cf) : "0"(output), "1"(cf) : "cc");
   #elif defined(BOTAN_TARGET_ARCH_IS_X86_32)
   cf = _rdrand32_step(&output);
   #else
   cf = _rdrand64_step(&output);
   #endif
   success = (1 == cf);

#elif defined(BOTAN_TARGET_CPU_IS_PPC_FAMILY)

   /*
   DARN indicates error by returning 0xFF..FF, ie is biased. Which is crazy.
   Avoid the bias by invoking it twice and, assuming both succeed, returning the
   XOR of the two results, which should unbias the output.
   */
   uint64_t output2 = 0;
   // DARN codes are 0: 32-bit conditioned, 1: 64-bit conditioned, 2: 64-bit raw (ala RDSEED)
   asm volatile("darn %0, 1" : "=r"(output));
   asm volatile("darn %0, 1" : "=r"(output2));

   if((~output) != 0 && (~output2) != 0) {
      output ^= output2;
      success = true;
   }

#endif

   if(success)
      return output;

   return 0;
}

hwrng_output read_hwrng() {
   for(size_t i = 0; i < HWRNG_RETRIES; ++i) {
      bool success = false;
      hwrng_output output = read_hwrng(success);

      if(success)
         return output;
   }

   throw PRNG_Unseeded("Processor RNG instruction failed to produce output within expected iterations");
}

}

//static
bool Processor_RNG::available() {
#if defined(BOTAN_TARGET_CPU_IS_X86_FAMILY)
   return CPUID::has_rdrand();
#elif defined(BOTAN_TARGET_CPU_IS_PPC_FAMILY)
   return CPUID::has_darn_rng();
#else
   return false;
#endif
}

std::string Processor_RNG::name() const {
#if defined(BOTAN_TARGET_CPU_IS_X86_FAMILY)
   return "rdrand";
#elif defined(BOTAN_TARGET_CPU_IS_PPC_FAMILY)
   return "darn";
#else
   return "hwrng";
#endif
}

void Processor_RNG::fill_bytes_with_input(std::span<uint8_t> out, std::span<const uint8_t> in) {
   // No way to provide entropy to processor-specific generator, ignore...
   BOTAN_UNUSED(in);

   while(out.size() >= sizeof(hwrng_output)) {
      const hwrng_output r = read_hwrng();
      store_le(r, out.data());
      out = out.subspan(sizeof(hwrng_output));
   }

   if(!out.empty())  // at most sizeof(hwrng_output)-1
   {
      const hwrng_output r = read_hwrng();
      uint8_t hwrng_bytes[sizeof(hwrng_output)];
      store_le(r, hwrng_bytes);

      for(size_t i = 0; i != out.size(); ++i)
         out[i] = hwrng_bytes[i];
   }
}

Processor_RNG::Processor_RNG() {
   if(!Processor_RNG::available())
      throw Invalid_State("Current CPU does not support RNG instruction");
}

size_t Processor_RNG::reseed(Entropy_Sources& /*srcs*/,
                             size_t /*poll_bits*/,
                             std::chrono::milliseconds /*poll_timeout*/) {
   /* no way to add entropy */
   return 0;
}

}

1	/*
2	* (C) 2016,2019,2020 Jack Lloyd
3	*
4	* Botan is released under the Simplified BSD License (see license.txt)
5	*/
6
7	#include <botan/processor_rng.h>
8
9	#include <botan/internal/cpuid.h>
10	#include <botan/internal/loadstor.h>
11
12	#if defined(BOTAN_TARGET_CPU_IS_X86_FAMILY) && !defined(BOTAN_USE_GCC_INLINE_ASM)
13	#include <immintrin.h>
14	#endif
15
16	namespace Botan {
17
18	namespace {
19
20	#if defined(BOTAN_TARGET_CPU_IS_X86_FAMILY)
21	/*
22	* According to Intel, RDRAND is guaranteed to generate a random
23	* number within 10 retries on a working CPU
24	*/
25	const size_t HWRNG_RETRIES = 10;
26
27	#elif defined(BOTAN_TARGET_CPU_IS_PPC_FAMILY)
28	/**
29	* PowerISA 3.0 p.78:
30	* When the error value is obtained, software is expected to repeat the
31	* operation. [...] The recommended number of attempts may be
32	* implementation specific. In the absence of other guidance, ten attempts
33	* should be adequate.
34	*/
35	const size_t HWRNG_RETRIES = 10;
36
37	#else
38	/*
39	* Lacking specific guidance we give the CPU quite a bit of leeway
40	*/
41	const size_t HWRNG_RETRIES = 512;
42	#endif
43
44	#if defined(BOTAN_TARGET_ARCH_IS_X86_32)
45	typedef uint32_t hwrng_output;
46	#else
47	typedef uint64_t hwrng_output;
48	#endif
49
50	hwrng_output read_hwrng(bool& success) {	13,492✔
51	hwrng_output output = 0;	13,492✔
52	success = false;	13,492✔
53
54	#if defined(BOTAN_TARGET_CPU_IS_X86_FAMILY)
55	int cf = 0;	13,492✔
56	#if defined(BOTAN_USE_GCC_INLINE_ASM)
57	// same asm seq works for 32 and 64 bit
58	asm volatile("rdrand %0; adcl $0,%1" : "=r"(output), "=r"(cf) : "0"(output), "1"(cf) : "cc");	26,984✔
59	#elif defined(BOTAN_TARGET_ARCH_IS_X86_32)
60	cf = _rdrand32_step(&output);
61	#else
62	cf = _rdrand64_step(&output);
63	#endif
64	success = (1 == cf);	13,492✔
65
66	#elif defined(BOTAN_TARGET_CPU_IS_PPC_FAMILY)
67
68	/*
69	DARN indicates error by returning 0xFF..FF, ie is biased. Which is crazy.
70	Avoid the bias by invoking it twice and, assuming both succeed, returning the
71	XOR of the two results, which should unbias the output.
72	*/
73	uint64_t output2 = 0;
74	// DARN codes are 0: 32-bit conditioned, 1: 64-bit conditioned, 2: 64-bit raw (ala RDSEED)
75	asm volatile("darn %0, 1" : "=r"(output));
76	asm volatile("darn %0, 1" : "=r"(output2));
77
78	if((~output) != 0 && (~output2) != 0) {
79	output ^= output2;
80	success = true;
81	}
82
83	#endif
84
85	if(success)	13,492✔
86	return output;	13,492✔
87
88	return 0;
89	}
90
91	hwrng_output read_hwrng() {	13,492✔
92	for(size_t i = 0; i < HWRNG_RETRIES; ++i) {	13,492✔
93	bool success = false;	13,492✔
94	hwrng_output output = read_hwrng(success);	13,492✔
95
96	if(success)	13,492✔
97	return output;	13,492✔
98	}
99
100	throw PRNG_Unseeded("Processor RNG instruction failed to produce output within expected iterations");	×
101	}
102
103	}
104
105	//static
106	bool Processor_RNG::available() {	14✔
107	#if defined(BOTAN_TARGET_CPU_IS_X86_FAMILY)
108	return CPUID::has_rdrand();	14✔
109	#elif defined(BOTAN_TARGET_CPU_IS_PPC_FAMILY)
110	return CPUID::has_darn_rng();
111	#else
112	return false;
113	#endif
114	}
115
116	std::string Processor_RNG::name() const {	19✔
117	#if defined(BOTAN_TARGET_CPU_IS_X86_FAMILY)
118	return "rdrand";	19✔
119	#elif defined(BOTAN_TARGET_CPU_IS_PPC_FAMILY)
120	return "darn";
121	#else
122	return "hwrng";
123	#endif
124	}
125
126	void Processor_RNG::fill_bytes_with_input(std::span<uint8_t> out, std::span<const uint8_t> in) {	185✔
127	// No way to provide entropy to processor-specific generator, ignore...
128	BOTAN_UNUSED(in);	185✔
129
130	while(out.size() >= sizeof(hwrng_output)) {	13,565✔
131	const hwrng_output r = read_hwrng();	13,380✔
132	store_le(r, out.data());	13,380✔
133	out = out.subspan(sizeof(hwrng_output));	13,380✔
134	}
135
136	if(!out.empty()) // at most sizeof(hwrng_output)-1	185✔
137	{
138	const hwrng_output r = read_hwrng();	112✔
139	uint8_t hwrng_bytes[sizeof(hwrng_output)];	112✔
140	store_le(r, hwrng_bytes);	112✔
141
142	for(size_t i = 0; i != out.size(); ++i)	560✔
143	out[i] = hwrng_bytes[i];	448✔
144	}
145	}	185✔
146
147	Processor_RNG::Processor_RNG() {	7✔
148	if(!Processor_RNG::available())	7✔
149	throw Invalid_State("Current CPU does not support RNG instruction");	×
150	}	7✔
151
152	size_t Processor_RNG::reseed(Entropy_Sources& /srcs/,	1✔
153	size_t /poll_bits/,
154	std::chrono::milliseconds /poll_timeout/) {
155	/* no way to add entropy */
156	return 0;	1✔
157	}
158
159	}

randombit / botan / 5079590438

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