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1 | /** @file\r |
2 | Support routines for RDRAND instruction access.\r | |
3 | \r | |
4 | Copyright (c) 2013, Intel Corporation. All rights reserved.<BR>\r | |
5 | This program and the accompanying materials\r | |
6 | are licensed and made available under the terms and conditions of the BSD License\r | |
7 | which accompanies this distribution. The full text of the license may be found at\r | |
8 | http://opensource.org/licenses/bsd-license.php\r | |
9 | \r | |
10 | THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,\r | |
11 | WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.\r | |
12 | \r | |
13 | **/\r | |
14 | \r | |
15 | #include "RdRand.h"\r | |
16 | #include "AesCore.h"\r | |
17 | \r | |
18 | //\r | |
19 | // Bit mask used to determine if RdRand instruction is supported.\r | |
20 | //\r | |
21 | #define RDRAND_MASK 0x40000000\r | |
22 | \r | |
23 | /**\r | |
24 | Determines whether or not RDRAND instruction is supported by the host hardware.\r | |
25 | \r | |
26 | @retval EFI_SUCCESS RDRAND instruction supported.\r | |
27 | @retval EFI_UNSUPPORTED RDRAND instruction not supported.\r | |
28 | \r | |
29 | **/\r | |
30 | EFI_STATUS\r | |
31 | EFIAPI\r | |
32 | IsRdRandSupported (\r | |
33 | VOID\r | |
34 | )\r | |
35 | {\r | |
36 | EFI_STATUS Status;\r | |
37 | UINT32 RegEax;\r | |
38 | UINT32 RegEbx;\r | |
39 | UINT32 RegEcx;\r | |
40 | UINT32 RegEdx;\r | |
41 | BOOLEAN IsIntelCpu;\r | |
42 | \r | |
43 | Status = EFI_UNSUPPORTED;\r | |
44 | IsIntelCpu = FALSE;\r | |
45 | \r | |
46 | //\r | |
47 | // Checks whether the current processor is an Intel product by CPUID.\r | |
48 | //\r | |
49 | AsmCpuid (0, &RegEax, &RegEbx, &RegEcx, &RegEdx);\r | |
50 | if ((CompareMem ((CHAR8 *)(&RegEbx), "Genu", 4) == 0) &&\r | |
51 | (CompareMem ((CHAR8 *)(&RegEdx), "ineI", 4) == 0) &&\r | |
52 | (CompareMem ((CHAR8 *)(&RegEcx), "ntel", 4) == 0)) {\r | |
53 | IsIntelCpu = TRUE;\r | |
54 | }\r | |
55 | \r | |
56 | if (IsIntelCpu) {\r | |
57 | //\r | |
58 | // Determine RDRAND support by examining bit 30 of the ECX register returned by CPUID.\r | |
59 | // A value of 1 indicates that processor supports RDRAND instruction.\r | |
60 | //\r | |
61 | AsmCpuid (1, 0, 0, &RegEcx, 0);\r | |
62 | \r | |
63 | if ((RegEcx & RDRAND_MASK) == RDRAND_MASK) {\r | |
64 | Status = EFI_SUCCESS;\r | |
65 | }\r | |
66 | }\r | |
67 | \r | |
68 | return Status;\r | |
69 | }\r | |
70 | \r | |
71 | /**\r | |
72 | Calls RDRAND to obtain a 16-bit random number.\r | |
73 | \r | |
74 | @param[out] Rand Buffer pointer to store the random result.\r | |
75 | @param[in] NeedRetry Determine whether or not to loop retry.\r | |
76 | \r | |
77 | @retval EFI_SUCCESS RDRAND call was successful.\r | |
78 | @retval EFI_NOT_READY Failed attempts to call RDRAND.\r | |
79 | \r | |
80 | **/\r | |
81 | EFI_STATUS\r | |
82 | EFIAPI\r | |
83 | RdRand16 (\r | |
84 | OUT UINT16 *Rand,\r | |
85 | IN BOOLEAN NeedRetry\r | |
86 | )\r | |
87 | {\r | |
88 | UINT32 Index;\r | |
89 | UINT32 RetryCount;\r | |
90 | \r | |
91 | if (NeedRetry) {\r | |
92 | RetryCount = RETRY_LIMIT;\r | |
93 | } else {\r | |
94 | RetryCount = 1;\r | |
95 | }\r | |
96 | \r | |
97 | //\r | |
98 | // Perform a single call to RDRAND, or enter a loop call until RDRAND succeeds.\r | |
99 | //\r | |
100 | for (Index = 0; Index < RetryCount; Index++) {\r | |
101 | if (RdRand16Step (Rand)) {\r | |
102 | return EFI_SUCCESS;\r | |
103 | }\r | |
104 | }\r | |
105 | \r | |
106 | return EFI_NOT_READY;\r | |
107 | }\r | |
108 | \r | |
109 | /**\r | |
110 | Calls RDRAND to obtain a 32-bit random number.\r | |
111 | \r | |
112 | @param[out] Rand Buffer pointer to store the random result.\r | |
113 | @param[in] NeedRetry Determine whether or not to loop retry.\r | |
114 | \r | |
115 | @retval EFI_SUCCESS RDRAND call was successful.\r | |
116 | @retval EFI_NOT_READY Failed attempts to call RDRAND.\r | |
117 | \r | |
118 | **/\r | |
119 | EFI_STATUS\r | |
120 | EFIAPI\r | |
121 | RdRand32 (\r | |
122 | OUT UINT32 *Rand,\r | |
123 | IN BOOLEAN NeedRetry\r | |
124 | )\r | |
125 | {\r | |
126 | UINT32 Index;\r | |
127 | UINT32 RetryCount;\r | |
128 | \r | |
129 | if (NeedRetry) {\r | |
130 | RetryCount = RETRY_LIMIT;\r | |
131 | } else {\r | |
132 | RetryCount = 1;\r | |
133 | }\r | |
134 | \r | |
135 | //\r | |
136 | // Perform a single call to RDRAND, or enter a loop call until RDRAND succeeds.\r | |
137 | //\r | |
138 | for (Index = 0; Index < RetryCount; Index++) {\r | |
139 | if (RdRand32Step (Rand)) {\r | |
140 | return EFI_SUCCESS;\r | |
141 | }\r | |
142 | }\r | |
143 | \r | |
144 | return EFI_NOT_READY;\r | |
145 | }\r | |
146 | \r | |
147 | /**\r | |
148 | Calls RDRAND to obtain a 64-bit random number.\r | |
149 | \r | |
150 | @param[out] Rand Buffer pointer to store the random result.\r | |
151 | @param[in] NeedRetry Determine whether or not to loop retry.\r | |
152 | \r | |
153 | @retval EFI_SUCCESS RDRAND call was successful.\r | |
154 | @retval EFI_NOT_READY Failed attempts to call RDRAND.\r | |
155 | \r | |
156 | **/\r | |
157 | EFI_STATUS\r | |
158 | EFIAPI\r | |
159 | RdRand64 (\r | |
160 | OUT UINT64 *Rand,\r | |
161 | IN BOOLEAN NeedRetry\r | |
162 | )\r | |
163 | {\r | |
164 | UINT32 Index;\r | |
165 | UINT32 RetryCount;\r | |
166 | \r | |
167 | if (NeedRetry) {\r | |
168 | RetryCount = RETRY_LIMIT;\r | |
169 | } else {\r | |
170 | RetryCount = 1;\r | |
171 | }\r | |
172 | \r | |
173 | //\r | |
174 | // Perform a single call to RDRAND, or enter a loop call until RDRAND succeeds.\r | |
175 | //\r | |
176 | for (Index = 0; Index < RetryCount; Index++) {\r | |
177 | if (RdRand64Step (Rand)) {\r | |
178 | return EFI_SUCCESS;\r | |
179 | }\r | |
180 | }\r | |
181 | \r | |
182 | return EFI_NOT_READY;\r | |
183 | }\r | |
184 | \r | |
185 | /**\r | |
186 | Calls RDRAND to fill a buffer of arbitrary size with random bytes.\r | |
187 | \r | |
188 | @param[in] Length Size of the buffer, in bytes, to fill with.\r | |
189 | @param[out] RandBuffer Pointer to the buffer to store the random result.\r | |
190 | \r | |
191 | @retval EFI_SUCCESS Random bytes generation succeeded.\r | |
192 | @retval EFI_NOT_READY Failed to request random bytes.\r | |
193 | \r | |
194 | **/\r | |
195 | EFI_STATUS\r | |
196 | EFIAPI\r | |
197 | RdRandGetBytes (\r | |
198 | IN UINTN Length,\r | |
199 | OUT UINT8 *RandBuffer\r | |
200 | )\r | |
201 | {\r | |
202 | EFI_STATUS Status;\r | |
203 | UINT8 *Start;\r | |
204 | UINT8 *ResidualStart;\r | |
205 | UINTN *BlockStart;\r | |
206 | UINTN TempRand;\r | |
207 | UINTN Count;\r | |
208 | UINTN Residual;\r | |
209 | UINTN StartLen;\r | |
210 | UINTN BlockNum;\r | |
211 | UINTN Index;\r | |
212 | \r | |
213 | ResidualStart = NULL;\r | |
214 | TempRand = 0;\r | |
215 | \r | |
216 | //\r | |
217 | // Compute the address of the first word aligned (32/64-bit) block in the \r | |
218 | // destination buffer, depending on whether we are in 32- or 64-bit mode.\r | |
219 | //\r | |
220 | Start = RandBuffer;\r | |
221 | if (((UINT32)(UINTN)Start % (UINT32)sizeof(UINTN)) == 0) {\r | |
222 | BlockStart = (UINTN *)Start;\r | |
223 | Count = Length;\r | |
224 | StartLen = 0;\r | |
225 | } else {\r | |
226 | BlockStart = (UINTN *)(((UINTN)Start & ~(UINTN)(sizeof(UINTN) - 1)) + (UINTN)sizeof(UINTN));\r | |
227 | Count = Length - (sizeof (UINTN) - (UINT32)((UINTN)Start % sizeof (UINTN)));\r | |
228 | StartLen = (UINT32)((UINTN)BlockStart - (UINTN)Start);\r | |
229 | }\r | |
230 | \r | |
231 | //\r | |
232 | // Compute the number of word blocks and the remaining number of bytes.\r | |
233 | //\r | |
234 | Residual = Count % sizeof (UINTN);\r | |
235 | BlockNum = Count / sizeof (UINTN);\r | |
236 | if (Residual != 0) {\r | |
237 | ResidualStart = (UINT8 *) (BlockStart + BlockNum);\r | |
238 | }\r | |
239 | \r | |
240 | //\r | |
241 | // Obtain a temporary random number for use in the residuals. Failout if retry fails.\r | |
242 | //\r | |
243 | if (StartLen > 0) {\r | |
244 | Status = RdRandWord ((UINTN *) &TempRand, TRUE);\r | |
245 | if (EFI_ERROR (Status)) {\r | |
246 | return Status;\r | |
247 | }\r | |
248 | }\r | |
249 | \r | |
250 | //\r | |
251 | // Populate the starting mis-aligned block.\r | |
252 | //\r | |
253 | for (Index = 0; Index < StartLen; Index++) {\r | |
254 | Start[Index] = (UINT8)(TempRand & 0xff);\r | |
255 | TempRand = TempRand >> 8;\r | |
256 | }\r | |
257 | \r | |
258 | //\r | |
259 | // Populate the central aligned block. Fail out if retry fails.\r | |
260 | //\r | |
261 | Status = RdRandGetWords (BlockNum, (UINTN *)(BlockStart));\r | |
262 | if (EFI_ERROR (Status)) {\r | |
263 | return Status;\r | |
264 | }\r | |
265 | //\r | |
266 | // Populate the final mis-aligned block.\r | |
267 | //\r | |
268 | if (Residual > 0) {\r | |
269 | Status = RdRandWord ((UINTN *)&TempRand, TRUE);\r | |
270 | if (EFI_ERROR (Status)) {\r | |
271 | return Status;\r | |
272 | }\r | |
273 | for (Index = 0; Index < Residual; Index++) {\r | |
274 | ResidualStart[Index] = (UINT8)(TempRand & 0xff);\r | |
275 | TempRand = TempRand >> 8;\r | |
276 | }\r | |
277 | }\r | |
278 | \r | |
279 | return EFI_SUCCESS;\r | |
280 | }\r | |
281 | \r | |
282 | /**\r | |
283 | Creates a 128bit random value that is fully forward and backward prediction resistant,\r | |
284 | suitable for seeding a NIST SP800-90 Compliant, FIPS 1402-2 certifiable SW DRBG.\r | |
285 | This function takes multiple random numbers through RDRAND without intervening\r | |
286 | delays to ensure reseeding and performs AES-CBC-MAC over the data to compute the\r | |
287 | seed value.\r | |
288 | \r | |
289 | @param[out] SeedBuffer Pointer to a 128bit buffer to store the random seed.\r | |
290 | \r | |
291 | @retval EFI_SUCCESS Random seed generation succeeded.\r | |
292 | @retval EFI_NOT_READY Failed to request random bytes.\r | |
293 | \r | |
294 | **/\r | |
295 | EFI_STATUS\r | |
296 | EFIAPI\r | |
297 | RdRandGetSeed128 (\r | |
298 | OUT UINT8 *SeedBuffer\r | |
299 | )\r | |
300 | {\r | |
301 | EFI_STATUS Status;\r | |
302 | UINT8 RandByte[16];\r | |
303 | UINT8 Key[16];\r | |
304 | UINT8 Ffv[16];\r | |
305 | UINT8 Xored[16];\r | |
306 | UINT32 Index;\r | |
307 | UINT32 Index2;\r | |
308 | \r | |
309 | //\r | |
310 | // Chose an arbitary key and zero the feed_forward_value (FFV)\r | |
311 | //\r | |
312 | for (Index = 0; Index < 16; Index++) {\r | |
313 | Key[Index] = (UINT8) Index;\r | |
314 | Ffv[Index] = 0;\r | |
315 | }\r | |
316 | \r | |
317 | //\r | |
318 | // Perform CBC_MAC over 32 * 128 bit values, with 10us gaps between 128 bit value\r | |
319 | // The 10us gaps will ensure multiple reseeds within the HW RNG with a large design margin.\r | |
320 | //\r | |
321 | for (Index = 0; Index < 32; Index++) {\r | |
322 | MicroSecondDelay (10);\r | |
323 | Status = RdRandGetBytes (16, RandByte);\r | |
324 | if (EFI_ERROR (Status)) {\r | |
325 | return Status;\r | |
326 | }\r | |
327 | \r | |
328 | //\r | |
329 | // Perform XOR operations on two 128-bit value.\r | |
330 | //\r | |
331 | for (Index2 = 0; Index2 < 16; Index2++) {\r | |
332 | Xored[Index2] = RandByte[Index2] ^ Ffv[Index2];\r | |
333 | }\r | |
334 | \r | |
335 | AesEncrypt (Key, Xored, Ffv);\r | |
336 | }\r | |
337 | \r | |
338 | for (Index = 0; Index < 16; Index++) {\r | |
339 | SeedBuffer[Index] = Ffv[Index];\r | |
340 | }\r | |
341 | \r | |
342 | return EFI_SUCCESS;\r | |
343 | }\r | |
344 | \r | |
345 | /**\r | |
346 | Generate high-quality entropy source through RDRAND.\r | |
347 | \r | |
348 | @param[in] Length Size of the buffer, in bytes, to fill with.\r | |
349 | @param[out] Entropy Pointer to the buffer to store the entropy data.\r | |
350 | \r | |
351 | @retval EFI_SUCCESS Entropy generation succeeded.\r | |
352 | @retval EFI_NOT_READY Failed to request random data.\r | |
353 | \r | |
354 | **/\r | |
355 | EFI_STATUS\r | |
356 | EFIAPI\r | |
357 | RdRandGenerateEntropy (\r | |
358 | IN UINTN Length,\r | |
359 | OUT UINT8 *Entropy\r | |
360 | )\r | |
361 | {\r | |
362 | EFI_STATUS Status;\r | |
363 | UINTN BlockCount;\r | |
364 | UINT8 Seed[16];\r | |
365 | UINT8 *Ptr;\r | |
366 | \r | |
367 | Status = EFI_NOT_READY;\r | |
368 | BlockCount = Length / 16;\r | |
369 | Ptr = (UINT8 *)Entropy;\r | |
370 | \r | |
371 | //\r | |
372 | // Generate high-quality seed for DRBG Entropy\r | |
373 | //\r | |
374 | while (BlockCount > 0) {\r | |
375 | Status = RdRandGetSeed128 (Seed);\r | |
376 | if (EFI_ERROR (Status)) {\r | |
377 | return Status;\r | |
378 | }\r | |
379 | CopyMem (Ptr, Seed, 16);\r | |
380 | \r | |
381 | BlockCount--;\r | |
382 | Ptr = Ptr + 16;\r | |
383 | }\r | |
384 | \r | |
385 | //\r | |
386 | // Populate the remained data as request.\r | |
387 | //\r | |
388 | Status = RdRandGetSeed128 (Seed);\r | |
389 | if (EFI_ERROR (Status)) {\r | |
390 | return Status;\r | |
391 | }\r | |
392 | CopyMem (Ptr, Seed, (Length % 16));\r | |
393 | \r | |
394 | return Status;\r | |
395 | }\r |