blob: 4a7cae78f85cf8c8a1849e93fb919f0be3960975 (
plain)
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
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
|
/** @file
BaseRng Library that uses the TimerLib to provide reasonably random numbers.
Do not use this on a production system.
Copyright (c) Microsoft Corporation.
SPDX-License-Identifier: BSD-2-Clause-Patent
**/
#include <Base.h>
#include <Library/BaseLib.h>
#include <Library/DebugLib.h>
#include <Library/TimerLib.h>
#define DEFAULT_DELAY_TIME_IN_MICROSECONDS 10
/**
This implementation is to be replaced by its MdeModulePkg copy.
The cause being that some GUIDs (gEdkiiRngAlgorithmUnSafe) cannot
be defined in the MdePkg.
@retval EFI_SUCCESS The constructor always returns EFI_SUCCESS.
**/
RETURN_STATUS
EFIAPI
BaseRngLibTimerConstructor (
VOID
)
{
DEBUG ((
DEBUG_WARN,
"Warning: This BaseRngTimerLib implementation will be deprecated. "
"Please use the MdeModulePkg implementation equivalent.\n"
));
return RETURN_SUCCESS;
}
/**
Using the TimerLib GetPerformanceCounterProperties() we delay
for enough time for the PerformanceCounter to increment.
If the return value from GetPerformanceCounterProperties (TimerLib)
is zero, this function will return 10 and attempt to assert.
**/
STATIC
UINT32
CalculateMinimumDecentDelayInMicroseconds (
VOID
)
{
UINT64 CounterHz;
// Get the counter properties
CounterHz = GetPerformanceCounterProperties (NULL, NULL);
// Make sure we won't divide by zero
if (CounterHz == 0) {
ASSERT (CounterHz != 0); // Assert so the developer knows something is wrong
return DEFAULT_DELAY_TIME_IN_MICROSECONDS;
}
// Calculate the minimum delay based on 1.5 microseconds divided by the hertz.
// We calculate the length of a cycle (1/CounterHz) and multiply it by 1.5 microseconds
// This ensures that the performance counter has increased by at least one
return (UINT32)(MAX (DivU64x64Remainder (1500000, CounterHz, NULL), 1));
}
/**
Generates a 16-bit random number.
if Rand is NULL, then ASSERT().
@param[out] Rand Buffer pointer to store the 16-bit random value.
@retval TRUE Random number generated successfully.
@retval FALSE Failed to generate the random number.
**/
BOOLEAN
EFIAPI
GetRandomNumber16 (
OUT UINT16 *Rand
)
{
UINT32 Index;
UINT8 *RandPtr;
UINT32 DelayInMicroSeconds;
ASSERT (Rand != NULL);
if (Rand == NULL) {
return FALSE;
}
DelayInMicroSeconds = CalculateMinimumDecentDelayInMicroseconds ();
RandPtr = (UINT8 *)Rand;
// Get 2 bytes of random ish data
for (Index = 0; Index < sizeof (UINT16); Index++) {
*RandPtr = (UINT8)(GetPerformanceCounter () & 0xFF);
// Delay to give the performance counter a chance to change
MicroSecondDelay (DelayInMicroSeconds);
RandPtr++;
}
return TRUE;
}
/**
Generates a 32-bit random number.
if Rand is NULL, then ASSERT().
@param[out] Rand Buffer pointer to store the 32-bit random value.
@retval TRUE Random number generated successfully.
@retval FALSE Failed to generate the random number.
**/
BOOLEAN
EFIAPI
GetRandomNumber32 (
OUT UINT32 *Rand
)
{
UINT32 Index;
UINT8 *RandPtr;
UINT32 DelayInMicroSeconds;
ASSERT (Rand != NULL);
if (NULL == Rand) {
return FALSE;
}
RandPtr = (UINT8 *)Rand;
DelayInMicroSeconds = CalculateMinimumDecentDelayInMicroseconds ();
// Get 4 bytes of random ish data
for (Index = 0; Index < sizeof (UINT32); Index++) {
*RandPtr = (UINT8)(GetPerformanceCounter () & 0xFF);
// Delay to give the performance counter a chance to change
MicroSecondDelay (DelayInMicroSeconds);
RandPtr++;
}
return TRUE;
}
/**
Generates a 64-bit random number.
if Rand is NULL, then ASSERT().
@param[out] Rand Buffer pointer to store the 64-bit random value.
@retval TRUE Random number generated successfully.
@retval FALSE Failed to generate the random number.
**/
BOOLEAN
EFIAPI
GetRandomNumber64 (
OUT UINT64 *Rand
)
{
UINT32 Index;
UINT8 *RandPtr;
UINT32 DelayInMicroSeconds;
ASSERT (Rand != NULL);
if (NULL == Rand) {
return FALSE;
}
RandPtr = (UINT8 *)Rand;
DelayInMicroSeconds = CalculateMinimumDecentDelayInMicroseconds ();
// Get 8 bytes of random ish data
for (Index = 0; Index < sizeof (UINT64); Index++) {
*RandPtr = (UINT8)(GetPerformanceCounter () & 0xFF);
// Delay to give the performance counter a chance to change
MicroSecondDelay (DelayInMicroSeconds);
RandPtr++;
}
return TRUE;
}
/**
Generates a 128-bit random number.
if Rand is NULL, then ASSERT().
@param[out] Rand Buffer pointer to store the 128-bit random value.
@retval TRUE Random number generated successfully.
@retval FALSE Failed to generate the random number.
**/
BOOLEAN
EFIAPI
GetRandomNumber128 (
OUT UINT64 *Rand
)
{
ASSERT (Rand != NULL);
// This should take around 80ms
// Read first 64 bits
if (!GetRandomNumber64 (Rand)) {
return FALSE;
}
// Read second 64 bits
return GetRandomNumber64 (++Rand);
}
/**
Get a GUID identifying the RNG algorithm implementation.
@param [out] RngGuid If success, contains the GUID identifying
the RNG algorithm implementation.
@retval EFI_SUCCESS Success.
@retval EFI_UNSUPPORTED Not supported.
@retval EFI_INVALID_PARAMETER Invalid parameter.
**/
RETURN_STATUS
EFIAPI
GetRngGuid (
GUID *RngGuid
)
{
/* This implementation is to be replaced by its MdeModulePkg copy.
* The cause being that some GUIDs (gEdkiiRngAlgorithmUnSafe) cannot
* be defined in the MdePkg.
*/
return RETURN_UNSUPPORTED;
}
|