1 /*############################################################################
2 # Copyright 2016-2017 Intel Corporation
3 #
4 # Licensed under the Apache License, Version 2.0 (the "License");
5 # you may not use this file except in compliance with the License.
6 # You may obtain a copy of the License at
7 #
8 # http://www.apache.org/licenses/LICENSE-2.0
9 #
10 # Unless required by applicable law or agreed to in writing, software
11 # distributed under the License is distributed on an "AS IS" BASIS,
12 # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 # See the License for the specific language governing permissions and
14 # limitations under the License.
15 ############################################################################*/
16
17 /*!
18 * \file
19 * \brief Pseudo random number generator implementation.
20 */
21 #include <ippcp.h>
22 #include <stdlib.h>
23 #include <time.h>
24
25 #include "src/prng.h"
26
PrngCreate(void ** prng)27 EpidStatus PrngCreate(void** prng) {
28 // Security note:
29 // Random number generator used in the samples not claimed to be a
30 // cryptographically secure pseudo-random number generator.
31 EpidStatus sts = kEpidErr;
32 int prng_ctx_size = 0;
33 IppsPRNGState* prng_ctx = NULL;
34 int seed_ctx_size = 0;
35 IppsBigNumState* seed_ctx = NULL;
36 time_t seed_value;
37
38 if (!prng) return kEpidBadArgErr;
39
40 if (ippStsNoErr != ippsPRNGGetSize(&prng_ctx_size)) return kEpidErr;
41 if (ippStsNoErr !=
42 ippsBigNumGetSize((sizeof(seed_value) + 3) / 4, &seed_ctx_size))
43 return kEpidErr;
44
45 do {
46 prng_ctx = (IppsPRNGState*)calloc(1, prng_ctx_size);
47
48 if (!prng_ctx) {
49 sts = kEpidNoMemErr;
50 break;
51 }
52 if (ippStsNoErr != ippsPRNGInit(sizeof(seed_value) * 8, prng_ctx)) {
53 sts = kEpidErr;
54 break;
55 }
56
57 // seed PRNG
58 seed_ctx = (IppsBigNumState*)calloc(1, seed_ctx_size);
59 if (!seed_ctx) {
60 sts = kEpidNoMemErr;
61 break;
62 }
63 if (ippStsNoErr != ippsBigNumInit((sizeof(seed_value) + 3) / 4, seed_ctx)) {
64 sts = kEpidErr;
65 break;
66 }
67 time(&seed_value);
68 if (ippStsNoErr !=
69 ippsSetOctString_BN((void*)&seed_value, sizeof(seed_value), seed_ctx)) {
70 sts = kEpidErr;
71 break;
72 }
73 if (ippStsNoErr != ippsPRNGSetSeed(seed_ctx, prng_ctx)) {
74 sts = kEpidErr;
75 break;
76 }
77
78 *prng = prng_ctx;
79 prng_ctx = NULL;
80 sts = kEpidNoErr;
81 } while (0);
82
83 if (seed_ctx) free(seed_ctx);
84 if (prng_ctx) free(prng_ctx);
85 return sts;
86 }
87
PrngDelete(void ** prng)88 void PrngDelete(void** prng) {
89 if (prng && *prng) {
90 free(*prng);
91 *prng = NULL;
92 }
93 }
94
95 // simple wrapper to hide IPP implementation.
PrngGen(unsigned int * rand_data,int num_bits,void * user_data)96 int __STDCALL PrngGen(unsigned int* rand_data, int num_bits, void* user_data) {
97 return ippsPRNGen(rand_data, num_bits, (IppsPRNGState*)user_data);
98 }
99