1 /*
2 * Platform-specific and custom entropy polling functions
3 *
4 * Copyright (C) 2006-2016, ARM Limited, All Rights Reserved
5 * SPDX-License-Identifier: Apache-2.0
6 *
7 * Licensed under the Apache License, Version 2.0 (the "License"); you may
8 * not use this file except in compliance with the License.
9 * You may obtain a copy of the License at
10 *
11 * http://www.apache.org/licenses/LICENSE-2.0
12 *
13 * Unless required by applicable law or agreed to in writing, software
14 * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
15 * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
16 * See the License for the specific language governing permissions and
17 * limitations under the License.
18 *
19 * This file is part of mbed TLS (https://tls.mbed.org)
20 */
21
22 #if defined(__linux__)
23 /* Ensure that syscall() is available even when compiling with -std=c99 */
24 #define _GNU_SOURCE
25 #endif
26
27 #if !defined(MBEDTLS_CONFIG_FILE)
28 #include "mbedtls/config.h"
29 #else
30 #include MBEDTLS_CONFIG_FILE
31 #endif
32
33 #include <string.h>
34
35 #if defined(MBEDTLS_ENTROPY_C)
36
37 #include "mbedtls/entropy.h"
38 #include "mbedtls/entropy_poll.h"
39
40 #if defined(MBEDTLS_TIMING_C)
41 #include "mbedtls/timing.h"
42 #endif
43 #if defined(MBEDTLS_HAVEGE_C)
44 #include "mbedtls/havege.h"
45 #endif
46 #if defined(MBEDTLS_ENTROPY_NV_SEED)
47 #include "mbedtls/platform.h"
48 #endif
49
50 #if !defined(MBEDTLS_NO_PLATFORM_ENTROPY)
51
52 #if !defined(unix) && !defined(__unix__) && !defined(__unix) && \
53 !defined(__APPLE__) && !defined(_WIN32) && !defined(__QNXNTO__) && !defined(__CSKY__) && \
54 !defined(__HAIKU__)
55 #error "Platform entropy sources only work on Unix and Windows, see MBEDTLS_NO_PLATFORM_ENTROPY in config.h"
56 #endif
57
58 #if defined(_WIN32) && !defined(EFIX64) && !defined(EFI32)
59
60 #if !defined(_WIN32_WINNT)
61 #define _WIN32_WINNT 0x0400
62 #endif
63 #include <windows.h>
64 #include <wincrypt.h>
65
mbedtls_platform_entropy_poll(void * data,unsigned char * output,size_t len,size_t * olen)66 int mbedtls_platform_entropy_poll( void *data, unsigned char *output, size_t len,
67 size_t *olen )
68 {
69 HCRYPTPROV provider;
70 ((void) data);
71 *olen = 0;
72
73 if( CryptAcquireContext( &provider, NULL, NULL,
74 PROV_RSA_FULL, CRYPT_VERIFYCONTEXT ) == FALSE )
75 {
76 return( MBEDTLS_ERR_ENTROPY_SOURCE_FAILED );
77 }
78
79 if( CryptGenRandom( provider, (DWORD) len, output ) == FALSE )
80 {
81 CryptReleaseContext( provider, 0 );
82 return( MBEDTLS_ERR_ENTROPY_SOURCE_FAILED );
83 }
84
85 CryptReleaseContext( provider, 0 );
86 *olen = len;
87
88 return( 0 );
89 }
90 #else /* _WIN32 && !EFIX64 && !EFI32 */
91
92 /*
93 * Test for Linux getrandom() support.
94 * Since there is no wrapper in the libc yet, use the generic syscall wrapper
95 * available in GNU libc and compatible libc's (eg uClibc).
96 */
97 #if defined(__linux__) && defined(__GLIBC__)
98 #include <unistd.h>
99 #include <sys/syscall.h>
100 #if defined(SYS_getrandom)
101 #define HAVE_GETRANDOM
102 #include <errno.h>
103
getrandom_wrapper(void * buf,size_t buflen,unsigned int flags)104 static int getrandom_wrapper( void *buf, size_t buflen, unsigned int flags )
105 {
106 /* MemSan cannot understand that the syscall writes to the buffer */
107 #if defined(__has_feature)
108 #if __has_feature(memory_sanitizer)
109 memset( buf, 0, buflen );
110 #endif
111 #endif
112 return( syscall( SYS_getrandom, buf, buflen, flags ) );
113 }
114 #endif /* SYS_getrandom */
115 #endif /* __linux__ */
116
117 #include <stdio.h>
118
mbedtls_platform_entropy_poll(void * data,unsigned char * output,size_t len,size_t * olen)119 int mbedtls_platform_entropy_poll( void *data,
120 unsigned char *output, size_t len, size_t *olen )
121 {
122 FILE *file;
123 size_t read_len;
124 int ret;
125 ((void) data);
126
127 #if defined(HAVE_GETRANDOM)
128 ret = getrandom_wrapper( output, len, 0 );
129 if( ret >= 0 )
130 {
131 *olen = ret;
132 return( 0 );
133 }
134 else if( errno != ENOSYS )
135 return( MBEDTLS_ERR_ENTROPY_SOURCE_FAILED );
136 /* Fall through if the system call isn't known. */
137 #else
138 ((void) ret);
139 #endif /* HAVE_GETRANDOM */
140
141 *olen = 0;
142
143 #if !defined(__CSKY__)
144 file = fopen( "/dev/urandom", "rb" );
145 if( file == NULL )
146 return( MBEDTLS_ERR_ENTROPY_SOURCE_FAILED );
147
148 read_len = fread( output, 1, len, file );
149 if( read_len != len )
150 {
151 fclose( file );
152 return( MBEDTLS_ERR_ENTROPY_SOURCE_FAILED );
153 }
154
155 fclose( file );
156 #else
157 ((void) file);
158 extern void * memcpy( void *, const void *, size_t );
159 //FIXME: fack random
160 memcpy(output, (void *)&read_len, len);
161 #endif
162 *olen = len;
163
164 return( 0 );
165 }
166 #endif /* _WIN32 && !EFIX64 && !EFI32 */
167 #endif /* !MBEDTLS_NO_PLATFORM_ENTROPY */
168
169 #if defined(MBEDTLS_TEST_NULL_ENTROPY)
mbedtls_null_entropy_poll(void * data,unsigned char * output,size_t len,size_t * olen)170 int mbedtls_null_entropy_poll( void *data,
171 unsigned char *output, size_t len, size_t *olen )
172 {
173 ((void) data);
174 ((void) output);
175 *olen = 0;
176
177 if( len < sizeof(unsigned char) )
178 return( 0 );
179
180 *olen = sizeof(unsigned char);
181
182 return( 0 );
183 }
184 #endif
185
186 #if defined(MBEDTLS_TIMING_C)
mbedtls_hardclock_poll(void * data,unsigned char * output,size_t len,size_t * olen)187 int mbedtls_hardclock_poll( void *data,
188 unsigned char *output, size_t len, size_t *olen )
189 {
190 unsigned long timer = mbedtls_timing_hardclock();
191 ((void) data);
192 *olen = 0;
193
194 if( len < sizeof(unsigned long) )
195 return( 0 );
196
197 memcpy( output, &timer, sizeof(unsigned long) );
198 *olen = sizeof(unsigned long);
199
200 return( 0 );
201 }
202 #endif /* MBEDTLS_TIMING_C */
203
204 #if defined(MBEDTLS_HAVEGE_C)
mbedtls_havege_poll(void * data,unsigned char * output,size_t len,size_t * olen)205 int mbedtls_havege_poll( void *data,
206 unsigned char *output, size_t len, size_t *olen )
207 {
208 mbedtls_havege_state *hs = (mbedtls_havege_state *) data;
209 *olen = 0;
210
211 if( mbedtls_havege_random( hs, output, len ) != 0 )
212 return( MBEDTLS_ERR_ENTROPY_SOURCE_FAILED );
213
214 *olen = len;
215
216 return( 0 );
217 }
218 #endif /* MBEDTLS_HAVEGE_C */
219
220 #if defined(MBEDTLS_ENTROPY_NV_SEED)
mbedtls_nv_seed_poll(void * data,unsigned char * output,size_t len,size_t * olen)221 int mbedtls_nv_seed_poll( void *data,
222 unsigned char *output, size_t len, size_t *olen )
223 {
224 unsigned char buf[MBEDTLS_ENTROPY_BLOCK_SIZE];
225 size_t use_len = MBEDTLS_ENTROPY_BLOCK_SIZE;
226 ((void) data);
227
228 memset( buf, 0, MBEDTLS_ENTROPY_BLOCK_SIZE );
229
230 if( mbedtls_nv_seed_read( buf, MBEDTLS_ENTROPY_BLOCK_SIZE ) < 0 )
231 return( MBEDTLS_ERR_ENTROPY_SOURCE_FAILED );
232
233 if( len < use_len )
234 use_len = len;
235
236 memcpy( output, buf, use_len );
237 *olen = use_len;
238
239 return( 0 );
240 }
241 #endif /* MBEDTLS_ENTROPY_NV_SEED */
242
243 #endif /* MBEDTLS_ENTROPY_C */
244