1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
|
/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* vim: set ts=8 sts=2 et sw=2 tw=80: */
/* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at https://mozilla.org/MPL/2.0/. */
#include "mozilla/RandomNum.h"
#include <fcntl.h>
#ifdef XP_UNIX
# include <unistd.h>
#endif
#if defined(XP_WIN)
// Microsoft doesn't "officially" support using RtlGenRandom() directly
// anymore, and the Windows headers assume that __stdcall is
// the default calling convention (which is true when Microsoft uses this
// function to build their own CRT libraries).
// We will explicitly declare it with the proper calling convention.
# include "minwindef.h"
# define RtlGenRandom SystemFunction036
extern "C" BOOLEAN NTAPI RtlGenRandom(PVOID RandomBuffer,
ULONG RandomBufferLength);
#endif
#if defined(ANDROID) || defined(XP_DARWIN) || defined(__DragonFly__) || \
defined(__FreeBSD__) || defined(__NetBSD__) || defined(__OpenBSD__)
# include <stdlib.h>
# define USE_ARC4RANDOM
#endif
#if defined(__linux__)
# include <linux/random.h> // For GRND_NONBLOCK.
# include <sys/syscall.h> // For SYS_getrandom.
// Older glibc versions don't define SYS_getrandom, so we define it here if
// it's not available. See bug 995069.
# if defined(__x86_64__)
# define GETRANDOM_NR 318
# elif defined(__i386__)
# define GETRANDOM_NR 355
# elif defined(__aarch64__)
# define GETRANDOM_NR 278
# elif defined(__arm__)
# define GETRANDOM_NR 384
# elif defined(__powerpc__)
# define GETRANDOM_NR 359
# elif defined(__s390__)
# define GETRANDOM_NR 349
# elif defined(__mips__)
# include <sgidefs.h>
# if _MIPS_SIM == _MIPS_SIM_ABI32
# define GETRANDOM_NR 4353
# elif _MIPS_SIM == _MIPS_SIM_ABI64
# define GETRANDOM_NR 5313
# elif _MIPS_SIM == _MIPS_SIM_NABI32
# define GETRANDOM_NR 6317
# endif
# endif
# if defined(SYS_getrandom)
// We have SYS_getrandom. Use it to check GETRANDOM_NR. Only do this if we set
// GETRANDOM_NR so tier 3 platforms with recent glibc are not forced to define
// it for no good reason.
# if defined(GETRANDOM_NR)
static_assert(GETRANDOM_NR == SYS_getrandom,
"GETRANDOM_NR should match the actual SYS_getrandom value");
# endif
# else
# define SYS_getrandom GETRANDOM_NR
# endif
# if defined(GRND_NONBLOCK)
static_assert(GRND_NONBLOCK == 1,
"If GRND_NONBLOCK is not 1 the #define below is wrong");
# else
# define GRND_NONBLOCK 1
# endif
#endif // defined(__linux__)
namespace mozilla {
MFBT_API bool GenerateRandomBytesFromOS(void* aBuffer, size_t aLength) {
MOZ_ASSERT(aBuffer);
MOZ_ASSERT(aLength > 0);
#if defined(XP_WIN)
return !!RtlGenRandom(aBuffer, aLength);
#elif defined(USE_ARC4RANDOM) // defined(XP_WIN)
arc4random_buf(aBuffer, aLength);
return true;
#elif defined(XP_UNIX) // defined(USE_ARC4RANDOM)
# if defined(__linux__)
long bytesGenerated = syscall(SYS_getrandom, aBuffer, aLength, GRND_NONBLOCK);
if (static_cast<unsigned long>(bytesGenerated) == aLength) {
return true;
}
// Fall-through to UNIX behavior if failed
# endif // defined(__linux__)
int fd = open("/dev/urandom", O_RDONLY);
if (fd < 0) {
return false;
}
ssize_t bytesRead = read(fd, aBuffer, aLength);
close(fd);
return (static_cast<size_t>(bytesRead) == aLength);
#else // defined(XP_UNIX)
# error "Platform needs to implement GenerateRandomBytesFromOS()"
#endif
}
MFBT_API Maybe<uint64_t> RandomUint64() {
uint64_t randomNum;
if (!GenerateRandomBytesFromOS(&randomNum, sizeof(randomNum))) {
return Nothing();
}
return Some(randomNum);
}
MFBT_API uint64_t RandomUint64OrDie() {
uint64_t randomNum;
MOZ_RELEASE_ASSERT(GenerateRandomBytesFromOS(&randomNum, sizeof(randomNum)));
return randomNum;
}
} // namespace mozilla
|
