tvl-depot/absl/random/internal/seed_material.cc
Abseil Team e9324d926a Export of internal Abseil changes.
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7a6ff16a85beb730c172d5d25cf1b5e1be885c56 by Laramie Leavitt <lar@google.com>:

Internal change.

PiperOrigin-RevId: 254454546

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ff8f9bafaefc26d451f576ea4a06d150aed63f6f by Andy Soffer <asoffer@google.com>:

Internal changes

PiperOrigin-RevId: 254451562

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deefc5b651b479ce36f0b4ef203e119c0c8936f2 by CJ Johnson <johnsoncj@google.com>:

Account for subtracting unsigned values from the size of InlinedVector

PiperOrigin-RevId: 254450625

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3c677316a27bcadc17e41957c809ca472d5fef14 by Andy Soffer <asoffer@google.com>:

Add C++17's std::make_from_tuple to absl/utility/utility.h

PiperOrigin-RevId: 254411573

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4ee3536a918830eeec402a28fc31a62c7c90b940 by CJ Johnson <johnsoncj@google.com>:

Adds benchmark for the rest of the InlinedVector public API

PiperOrigin-RevId: 254408378

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e5a21a00700ee83498ff1efbf649169756463ee4 by CJ Johnson <johnsoncj@google.com>:

Updates the definition of InlinedVector::shrink_to_fit() to be exception safe and adds exception safety tests for it.

PiperOrigin-RevId: 254401387

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2ea82e72b86d82d78b4e4712a63a55981b53c64b by Laramie Leavitt <lar@google.com>:

Use absl::InsecureBitGen in place of std::mt19937
in tests absl/random/...distribution_test.cc

PiperOrigin-RevId: 254289444

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fa099e02c413a7ffda732415e8105cad26a90337 by Andy Soffer <asoffer@google.com>:

Internal changes

PiperOrigin-RevId: 254286334

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ce34b7f36933b30cfa35b9c9a5697a792b5666e4 by Andy Soffer <asoffer@google.com>:

Internal changes

PiperOrigin-RevId: 254273059

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6f9c473da7c2090c2e85a37c5f00622e8a912a89 by Jorg Brown <jorg@google.com>:

Change absl::container_internal::CompressedTuple to instantiate its
internal Storage class with the name of the type it's holding, rather
than the name of the Tuple.  This is not an externally-visible change,
other than less compiler memory is used and less debug information is
generated.

PiperOrigin-RevId: 254269285

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8bd3c186bf2fc0c55d8a2dd6f28a5327502c9fba by Andy Soffer <asoffer@google.com>:

Adding short-hand IntervalClosed for IntervalClosedClosed and IntervalOpen for
IntervalOpenOpen.

PiperOrigin-RevId: 254252419

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ea957f99b6a04fccd42aa05605605f3b44b1ecfd by Abseil Team <absl-team@google.com>:

Do not directly use __SIZEOF_INT128__.

In order to avoid linker errors when building with clang-cl (__fixunsdfti, __udivti3 and __fixunssfti are undefined), this CL uses ABSL_HAVE_INTRINSIC_INT128 which is not defined for clang-cl.

PiperOrigin-RevId: 254250739

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89ab385cd26b34d64130bce856253aaba96d2345 by Andy Soffer <asoffer@google.com>:

Internal changes

PiperOrigin-RevId: 254242321

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cffc793d93eca6d6bdf7de733847b6ab4a255ae9 by CJ Johnson <johnsoncj@google.com>:

Adds benchmark for InlinedVector::reserve(size_type)

PiperOrigin-RevId: 254199226

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c90c7a9fa3c8f0c9d5114036979548b055ea2f2a by Gennadiy Rozental <rogeeff@google.com>:

Import of CCTZ from GitHub.

PiperOrigin-RevId: 254072387

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c4c388beae016c9570ab54ffa1d52660e4a85b7b by Laramie Leavitt <lar@google.com>:

Internal cleanup.

PiperOrigin-RevId: 254062381

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d3c992e221cc74e5372d0c8fa410170b6a43c062 by Tom Manshreck <shreck@google.com>:

Update distributions.h to Abseil standards

PiperOrigin-RevId: 254054946

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d15ad0035c34ef11b14fadc5a4a2d3ec415f5518 by CJ Johnson <johnsoncj@google.com>:

Removes functions with only one caller from the implementation details of InlinedVector by manually inlining the definitions

PiperOrigin-RevId: 254005427

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2f37e807efc3a8ef1f4b539bdd379917d4151520 by Andy Soffer <asoffer@google.com>:

Initial release of Abseil Random

PiperOrigin-RevId: 253999861

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24ed1694b6430791d781ed533a8f8ccf6cac5856 by CJ Johnson <johnsoncj@google.com>:

Updates the definition of InlinedVector::assign(...)/InlinedVector::operator=(...) to new, exception-safe implementations with exception safety tests to boot

PiperOrigin-RevId: 253993691

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5613d95f5a7e34a535cfaeadce801441e990843e by CJ Johnson <johnsoncj@google.com>:

Adds benchmarks for InlinedVector::shrink_to_fit()

PiperOrigin-RevId: 253989647

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2a96ddfdac40bbb8cb6a7f1aeab90917067c6e63 by Abseil Team <absl-team@google.com>:

Initial release of Abseil Random

PiperOrigin-RevId: 253927497

--
bf1aff8fc9ffa921ad74643e9525ecf25b0d8dc1 by Andy Soffer <asoffer@google.com>:

Initial release of Abseil Random

PiperOrigin-RevId: 253920512

--
bfc03f4a3dcda3cf3a4b84bdb84cda24e3394f41 by Laramie Leavitt <lar@google.com>:

Internal change.

PiperOrigin-RevId: 253886486

--
05036cfcc078ca7c5f581a00dfb0daed568cbb69 by Eric Fiselier <ericwf@google.com>:

Don't include `winsock2.h` because it drags in `windows.h` and friends,
and they define awful macros like OPAQUE, ERROR, and more. This has the
potential to break abseil users.

Instead we only forward declare `timeval` and require Windows users
include `winsock2.h` themselves. This is both inconsistent and poor QoI, but so
including 'windows.h' is bad too.

PiperOrigin-RevId: 253852615
GitOrigin-RevId: 7a6ff16a85beb730c172d5d25cf1b5e1be885c56
Change-Id: Icd6aff87da26f29ec8915da856f051129987cef6
2019-06-21 16:18:10 -04:00

204 lines
5.6 KiB
C++

// Copyright 2017 The Abseil Authors.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// https://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
#include "absl/random/internal/seed_material.h"
#include <fcntl.h>
#ifndef _WIN32
#include <unistd.h>
#else
#include <io.h>
#endif
#include <algorithm>
#include <cerrno>
#include <cstdint>
#include <cstdlib>
#include <cstring>
#include "absl/base/internal/raw_logging.h"
#include "absl/strings/ascii.h"
#include "absl/strings/escaping.h"
#include "absl/strings/string_view.h"
#include "absl/strings/strip.h"
#if defined(__native_client__)
#include <nacl/nacl_random.h>
#define ABSL_RANDOM_USE_NACL_SECURE_RANDOM 1
#elif defined(_WIN32)
#include <windows.h>
#define ABSL_RANDOM_USE_BCRYPT 1
#pragma comment(lib, "bcrypt.lib")
#endif
#if defined(ABSL_RANDOM_USE_BCRYPT)
#include <bcrypt.h>
#ifndef BCRYPT_SUCCESS
#define BCRYPT_SUCCESS(Status) (((NTSTATUS)(Status)) >= 0)
#endif
// Also link bcrypt; this can be done via linker options or:
// #pragma comment(lib, "bcrypt.lib")
#endif
namespace absl {
namespace random_internal {
namespace {
// Read OS Entropy for random number seeds.
// TODO(absl-team): Possibly place a cap on how much entropy may be read at a
// time.
#if defined(ABSL_RANDOM_USE_BCRYPT)
// On Windows potentially use the BCRYPT CNG API to read available entropy.
bool ReadSeedMaterialFromOSEntropyImpl(absl::Span<uint32_t> values) {
BCRYPT_ALG_HANDLE hProvider;
NTSTATUS ret;
ret = BCryptOpenAlgorithmProvider(&hProvider, BCRYPT_RNG_ALGORITHM,
MS_PRIMITIVE_PROVIDER, 0);
if (!(BCRYPT_SUCCESS(ret))) {
ABSL_RAW_LOG(ERROR, "Failed to open crypto provider.");
return false;
}
ret = BCryptGenRandom(
hProvider, // provider
reinterpret_cast<UCHAR*>(values.data()), // buffer
static_cast<ULONG>(sizeof(uint32_t) * values.size()), // bytes
0); // flags
BCryptCloseAlgorithmProvider(hProvider, 0);
return BCRYPT_SUCCESS(ret);
}
#elif defined(ABSL_RANDOM_USE_NACL_SECURE_RANDOM)
// On NaCL use nacl_secure_random to acquire bytes.
bool ReadSeedMaterialFromOSEntropyImpl(absl::Span<uint32_t> values) {
auto buffer = reinterpret_cast<uint8_t*>(values.data());
size_t buffer_size = sizeof(uint32_t) * values.size();
uint8_t* output_ptr = buffer;
while (buffer_size > 0) {
size_t nread = 0;
const int error = nacl_secure_random(output_ptr, buffer_size, &nread);
if (error != 0 || nread > buffer_size) {
ABSL_RAW_LOG(ERROR, "Failed to read secure_random seed data: %d", error);
return false;
}
output_ptr += nread;
buffer_size -= nread;
}
return true;
}
#else
// On *nix, read entropy from /dev/urandom.
bool ReadSeedMaterialFromOSEntropyImpl(absl::Span<uint32_t> values) {
const char kEntropyFile[] = "/dev/urandom";
auto buffer = reinterpret_cast<uint8_t*>(values.data());
size_t buffer_size = sizeof(uint32_t) * values.size();
int dev_urandom = open(kEntropyFile, O_RDONLY);
bool success = (-1 != dev_urandom);
if (!success) {
return false;
}
while (success && buffer_size > 0) {
int bytes_read = read(dev_urandom, buffer, buffer_size);
int read_error = errno;
success = (bytes_read > 0);
if (success) {
buffer += bytes_read;
buffer_size -= bytes_read;
} else if (bytes_read == -1 && read_error == EINTR) {
success = true; // Need to try again.
}
}
close(dev_urandom);
return success;
}
#endif
} // namespace
bool ReadSeedMaterialFromOSEntropy(absl::Span<uint32_t> values) {
assert(values.data() != nullptr);
if (values.data() == nullptr) {
return false;
}
if (values.empty()) {
return true;
}
return ReadSeedMaterialFromOSEntropyImpl(values);
}
void MixIntoSeedMaterial(absl::Span<const uint32_t> sequence,
absl::Span<uint32_t> seed_material) {
// Algorithm is based on code available at
// https://gist.github.com/imneme/540829265469e673d045
constexpr uint32_t kInitVal = 0x43b0d7e5;
constexpr uint32_t kHashMul = 0x931e8875;
constexpr uint32_t kMixMulL = 0xca01f9dd;
constexpr uint32_t kMixMulR = 0x4973f715;
constexpr uint32_t kShiftSize = sizeof(uint32_t) * 8 / 2;
uint32_t hash_const = kInitVal;
auto hash = [&](uint32_t value) {
value ^= hash_const;
hash_const *= kHashMul;
value *= hash_const;
value ^= value >> kShiftSize;
return value;
};
auto mix = [&](uint32_t x, uint32_t y) {
uint32_t result = kMixMulL * x - kMixMulR * y;
result ^= result >> kShiftSize;
return result;
};
for (const auto& seq_val : sequence) {
for (auto& elem : seed_material) {
elem = mix(elem, hash(seq_val));
}
}
}
absl::optional<uint32_t> GetSaltMaterial() {
// Salt must be common for all generators within the same process so read it
// only once and store in static variable.
static const auto salt_material = []() -> absl::optional<uint32_t> {
uint32_t salt_value = 0;
if (random_internal::ReadSeedMaterialFromOSEntropy(
MakeSpan(&salt_value, 1))) {
return salt_value;
}
return absl::nullopt;
}();
return salt_material;
}
} // namespace random_internal
} // namespace absl