1 /*
2 * PSA ITS simulator over stdio files.
3 */
4 /*
5 * Copyright The Mbed TLS Contributors
6 * SPDX-License-Identifier: Apache-2.0
7 *
8 * Licensed under the Apache License, Version 2.0 (the "License"); you may
9 * not use this file except in compliance with the License.
10 * You may obtain a copy of the License at
11 *
12 * http://www.apache.org/licenses/LICENSE-2.0
13 *
14 * Unless required by applicable law or agreed to in writing, software
15 * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
16 * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
17 * See the License for the specific language governing permissions and
18 * limitations under the License.
19 */
20
21 #include "common.h"
22
23 #if defined(MBEDTLS_PSA_ITS_FILE_C)
24
25 #include "mbedtls/platform.h"
26
27 #if defined(_WIN32)
28 #include <windows.h>
29 #endif
30
31 #include "psa_crypto_its.h"
32
33 #include <limits.h>
34 #include <stdint.h>
35 #include <stdio.h>
36 #include <string.h>
37
38 #if !defined(PSA_ITS_STORAGE_PREFIX)
39 #define PSA_ITS_STORAGE_PREFIX ""
40 #endif
41
42 #define PSA_ITS_STORAGE_FILENAME_PATTERN "%08x%08x"
43 #define PSA_ITS_STORAGE_SUFFIX ".psa_its"
44 #define PSA_ITS_STORAGE_FILENAME_LENGTH \
45 ( sizeof( PSA_ITS_STORAGE_PREFIX ) - 1 + /*prefix without terminating 0*/ \
46 16 + /*UID (64-bit number in hex)*/ \
47 sizeof( PSA_ITS_STORAGE_SUFFIX ) - 1 + /*suffix without terminating 0*/ \
48 1 /*terminating null byte*/ )
49 #define PSA_ITS_STORAGE_TEMP \
50 PSA_ITS_STORAGE_PREFIX "tempfile" PSA_ITS_STORAGE_SUFFIX
51
52 /* The maximum value of psa_storage_info_t.size */
53 #define PSA_ITS_MAX_SIZE 0xffffffff
54
55 #define PSA_ITS_MAGIC_STRING "PSA\0ITS\0"
56 #define PSA_ITS_MAGIC_LENGTH 8
57
58 /* As rename fails on Windows if the new filepath already exists,
59 * use MoveFileExA with the MOVEFILE_REPLACE_EXISTING flag instead.
60 * Returns 0 on success, nonzero on failure. */
61 #if defined(_WIN32)
62 #define rename_replace_existing( oldpath, newpath ) \
63 ( ! MoveFileExA( oldpath, newpath, MOVEFILE_REPLACE_EXISTING ) )
64 #else
65 #define rename_replace_existing( oldpath, newpath ) rename( oldpath, newpath )
66 #endif
67
68 typedef struct
69 {
70 uint8_t magic[PSA_ITS_MAGIC_LENGTH];
71 uint8_t size[sizeof( uint32_t )];
72 uint8_t flags[sizeof( psa_storage_create_flags_t )];
73 } psa_its_file_header_t;
74
psa_its_fill_filename(psa_storage_uid_t uid,char * filename)75 static void psa_its_fill_filename( psa_storage_uid_t uid, char *filename )
76 {
77 /* Break up the UID into two 32-bit pieces so as not to rely on
78 * long long support in snprintf. */
79 mbedtls_snprintf( filename, PSA_ITS_STORAGE_FILENAME_LENGTH,
80 "%s" PSA_ITS_STORAGE_FILENAME_PATTERN "%s",
81 PSA_ITS_STORAGE_PREFIX,
82 (unsigned) ( uid >> 32 ),
83 (unsigned) ( uid & 0xffffffff ),
84 PSA_ITS_STORAGE_SUFFIX );
85 }
86
psa_its_read_file(psa_storage_uid_t uid,struct psa_storage_info_t * p_info,FILE ** p_stream)87 static psa_status_t psa_its_read_file( psa_storage_uid_t uid,
88 struct psa_storage_info_t *p_info,
89 FILE **p_stream )
90 {
91 char filename[PSA_ITS_STORAGE_FILENAME_LENGTH];
92 psa_its_file_header_t header;
93 size_t n;
94
95 *p_stream = NULL;
96 psa_its_fill_filename( uid, filename );
97 *p_stream = fopen( filename, "rb" );
98 if( *p_stream == NULL )
99 return( PSA_ERROR_DOES_NOT_EXIST );
100
101 /* Ensure no stdio buffering of secrets, as such buffers cannot be wiped. */
102 mbedtls_setbuf( *p_stream, NULL );
103
104 n = fread( &header, 1, sizeof( header ), *p_stream );
105 if( n != sizeof( header ) )
106 return( PSA_ERROR_DATA_CORRUPT );
107 if( memcmp( header.magic, PSA_ITS_MAGIC_STRING,
108 PSA_ITS_MAGIC_LENGTH ) != 0 )
109 return( PSA_ERROR_DATA_CORRUPT );
110
111 p_info->size = ( header.size[0] |
112 header.size[1] << 8 |
113 header.size[2] << 16 |
114 header.size[3] << 24 );
115 p_info->flags = ( header.flags[0] |
116 header.flags[1] << 8 |
117 header.flags[2] << 16 |
118 header.flags[3] << 24 );
119 return( PSA_SUCCESS );
120 }
121
psa_its_get_info(psa_storage_uid_t uid,struct psa_storage_info_t * p_info)122 psa_status_t psa_its_get_info( psa_storage_uid_t uid,
123 struct psa_storage_info_t *p_info )
124 {
125 psa_status_t status;
126 FILE *stream = NULL;
127 status = psa_its_read_file( uid, p_info, &stream );
128 if( stream != NULL )
129 fclose( stream );
130 return( status );
131 }
132
psa_its_get(psa_storage_uid_t uid,uint32_t data_offset,uint32_t data_length,void * p_data,size_t * p_data_length)133 psa_status_t psa_its_get( psa_storage_uid_t uid,
134 uint32_t data_offset,
135 uint32_t data_length,
136 void *p_data,
137 size_t *p_data_length )
138 {
139 psa_status_t status;
140 FILE *stream = NULL;
141 size_t n;
142 struct psa_storage_info_t info;
143
144 status = psa_its_read_file( uid, &info, &stream );
145 if( status != PSA_SUCCESS )
146 goto exit;
147 status = PSA_ERROR_INVALID_ARGUMENT;
148 if( data_offset + data_length < data_offset )
149 goto exit;
150 #if SIZE_MAX < 0xffffffff
151 if( data_offset + data_length > SIZE_MAX )
152 goto exit;
153 #endif
154 if( data_offset + data_length > info.size )
155 goto exit;
156
157 status = PSA_ERROR_STORAGE_FAILURE;
158 #if LONG_MAX < 0xffffffff
159 while( data_offset > LONG_MAX )
160 {
161 if( fseek( stream, LONG_MAX, SEEK_CUR ) != 0 )
162 goto exit;
163 data_offset -= LONG_MAX;
164 }
165 #endif
166 if( fseek( stream, data_offset, SEEK_CUR ) != 0 )
167 goto exit;
168 n = fread( p_data, 1, data_length, stream );
169 if( n != data_length )
170 goto exit;
171 status = PSA_SUCCESS;
172 if( p_data_length != NULL )
173 *p_data_length = n;
174
175 exit:
176 if( stream != NULL )
177 fclose( stream );
178 return( status );
179 }
180
psa_its_set(psa_storage_uid_t uid,uint32_t data_length,const void * p_data,psa_storage_create_flags_t create_flags)181 psa_status_t psa_its_set( psa_storage_uid_t uid,
182 uint32_t data_length,
183 const void *p_data,
184 psa_storage_create_flags_t create_flags )
185 {
186 if( uid == 0 )
187 {
188 return( PSA_ERROR_INVALID_HANDLE );
189 }
190
191 psa_status_t status = PSA_ERROR_STORAGE_FAILURE;
192 char filename[PSA_ITS_STORAGE_FILENAME_LENGTH];
193 FILE *stream = NULL;
194 psa_its_file_header_t header;
195 size_t n;
196
197 memcpy( header.magic, PSA_ITS_MAGIC_STRING, PSA_ITS_MAGIC_LENGTH );
198 MBEDTLS_PUT_UINT32_LE( data_length, header.size, 0 );
199 MBEDTLS_PUT_UINT32_LE( create_flags, header.flags, 0 );
200
201 psa_its_fill_filename( uid, filename );
202 stream = fopen( PSA_ITS_STORAGE_TEMP, "wb" );
203
204 if( stream == NULL )
205 goto exit;
206
207 /* Ensure no stdio buffering of secrets, as such buffers cannot be wiped. */
208 mbedtls_setbuf( stream, NULL );
209
210 status = PSA_ERROR_INSUFFICIENT_STORAGE;
211 n = fwrite( &header, 1, sizeof( header ), stream );
212 if( n != sizeof( header ) )
213 goto exit;
214 if( data_length != 0 )
215 {
216 n = fwrite( p_data, 1, data_length, stream );
217 if( n != data_length )
218 goto exit;
219 }
220 status = PSA_SUCCESS;
221
222 exit:
223 if( stream != NULL )
224 {
225 int ret = fclose( stream );
226 if( status == PSA_SUCCESS && ret != 0 )
227 status = PSA_ERROR_INSUFFICIENT_STORAGE;
228 }
229 if( status == PSA_SUCCESS )
230 {
231 if( rename_replace_existing( PSA_ITS_STORAGE_TEMP, filename ) != 0 )
232 status = PSA_ERROR_STORAGE_FAILURE;
233 }
234 /* The temporary file may still exist, but only in failure cases where
235 * we're already reporting an error. So there's nothing we can do on
236 * failure. If the function succeeded, and in some error cases, the
237 * temporary file doesn't exist and so remove() is expected to fail.
238 * Thus we just ignore the return status of remove(). */
239 (void) remove( PSA_ITS_STORAGE_TEMP );
240 return( status );
241 }
242
psa_its_remove(psa_storage_uid_t uid)243 psa_status_t psa_its_remove( psa_storage_uid_t uid )
244 {
245 char filename[PSA_ITS_STORAGE_FILENAME_LENGTH];
246 FILE *stream;
247 psa_its_fill_filename( uid, filename );
248 stream = fopen( filename, "rb" );
249 if( stream == NULL )
250 return( PSA_ERROR_DOES_NOT_EXIST );
251 fclose( stream );
252 if( remove( filename ) != 0 )
253 return( PSA_ERROR_STORAGE_FAILURE );
254 return( PSA_SUCCESS );
255 }
256
257 #endif /* MBEDTLS_PSA_ITS_FILE_C */
258
