1 /*
2 * PSA ITS simulator over stdio files.
3 */
4 /*
5 * Copyright The Mbed TLS Contributors
6 * SPDX-License-Identifier: Apache-2.0 OR GPL-2.0-or-later
7 */
8
9 #include "common.h"
10
11 #if defined(MBEDTLS_PSA_ITS_FILE_C)
12
13 #include "mbedtls/platform.h"
14
15 #if defined(_WIN32)
16 #include <windows.h>
17 #endif
18
19 #include "psa_crypto_its.h"
20
21 #include <limits.h>
22 #include <stdint.h>
23 #include <stdio.h>
24 #include <string.h>
25
26 #if !defined(PSA_ITS_STORAGE_PREFIX)
27 #define PSA_ITS_STORAGE_PREFIX ""
28 #endif
29
30 #define PSA_ITS_STORAGE_FILENAME_PATTERN "%08x%08x"
31 #define PSA_ITS_STORAGE_SUFFIX ".psa_its"
32 #define PSA_ITS_STORAGE_FILENAME_LENGTH \
33 (sizeof(PSA_ITS_STORAGE_PREFIX) - 1 + /*prefix without terminating 0*/ \
34 16 + /*UID (64-bit number in hex)*/ \
35 sizeof(PSA_ITS_STORAGE_SUFFIX) - 1 + /*suffix without terminating 0*/ \
36 1 /*terminating null byte*/)
37 #define PSA_ITS_STORAGE_TEMP \
38 PSA_ITS_STORAGE_PREFIX "tempfile" PSA_ITS_STORAGE_SUFFIX
39
40 /* The maximum value of psa_storage_info_t.size */
41 #define PSA_ITS_MAX_SIZE 0xffffffff
42
43 #define PSA_ITS_MAGIC_STRING "PSA\0ITS\0"
44 #define PSA_ITS_MAGIC_LENGTH 8
45
46 /* As rename fails on Windows if the new filepath already exists,
47 * use MoveFileExA with the MOVEFILE_REPLACE_EXISTING flag instead.
48 * Returns 0 on success, nonzero on failure. */
49 #if defined(_WIN32)
50 #define rename_replace_existing(oldpath, newpath) \
51 (!MoveFileExA(oldpath, newpath, MOVEFILE_REPLACE_EXISTING))
52 #else
53 #define rename_replace_existing(oldpath, newpath) rename(oldpath, newpath)
54 #endif
55
56 typedef struct {
57 uint8_t magic[PSA_ITS_MAGIC_LENGTH];
58 uint8_t size[sizeof(uint32_t)];
59 uint8_t flags[sizeof(psa_storage_create_flags_t)];
60 } psa_its_file_header_t;
61
psa_its_fill_filename(psa_storage_uid_t uid,char * filename)62 static void psa_its_fill_filename(psa_storage_uid_t uid, char *filename)
63 {
64 /* Break up the UID into two 32-bit pieces so as not to rely on
65 * long long support in snprintf. */
66 mbedtls_snprintf(filename, PSA_ITS_STORAGE_FILENAME_LENGTH,
67 "%s" PSA_ITS_STORAGE_FILENAME_PATTERN "%s",
68 PSA_ITS_STORAGE_PREFIX,
69 (unsigned) (uid >> 32),
70 (unsigned) (uid & 0xffffffff),
71 PSA_ITS_STORAGE_SUFFIX);
72 }
73
psa_its_read_file(psa_storage_uid_t uid,struct psa_storage_info_t * p_info,FILE ** p_stream)74 static psa_status_t psa_its_read_file(psa_storage_uid_t uid,
75 struct psa_storage_info_t *p_info,
76 FILE **p_stream)
77 {
78 char filename[PSA_ITS_STORAGE_FILENAME_LENGTH];
79 psa_its_file_header_t header;
80 size_t n;
81
82 *p_stream = NULL;
83 psa_its_fill_filename(uid, filename);
84 *p_stream = fopen(filename, "rb");
85 if (*p_stream == NULL) {
86 return PSA_ERROR_DOES_NOT_EXIST;
87 }
88
89 n = fread(&header, 1, sizeof(header), *p_stream);
90 if (n != sizeof(header)) {
91 return PSA_ERROR_DATA_CORRUPT;
92 }
93 if (memcmp(header.magic, PSA_ITS_MAGIC_STRING,
94 PSA_ITS_MAGIC_LENGTH) != 0) {
95 return PSA_ERROR_DATA_CORRUPT;
96 }
97
98 p_info->size = (header.size[0] |
99 header.size[1] << 8 |
100 header.size[2] << 16 |
101 header.size[3] << 24);
102 p_info->flags = (header.flags[0] |
103 header.flags[1] << 8 |
104 header.flags[2] << 16 |
105 header.flags[3] << 24);
106 return PSA_SUCCESS;
107 }
108
psa_its_get_info(psa_storage_uid_t uid,struct psa_storage_info_t * p_info)109 psa_status_t psa_its_get_info(psa_storage_uid_t uid,
110 struct psa_storage_info_t *p_info)
111 {
112 psa_status_t status;
113 FILE *stream = NULL;
114 status = psa_its_read_file(uid, p_info, &stream);
115 if (stream != NULL) {
116 fclose(stream);
117 }
118 return status;
119 }
120
psa_its_get(psa_storage_uid_t uid,uint32_t data_offset,uint32_t data_length,void * p_data,size_t * p_data_length)121 psa_status_t psa_its_get(psa_storage_uid_t uid,
122 uint32_t data_offset,
123 uint32_t data_length,
124 void *p_data,
125 size_t *p_data_length)
126 {
127 psa_status_t status;
128 FILE *stream = NULL;
129 size_t n;
130 struct psa_storage_info_t info;
131
132 status = psa_its_read_file(uid, &info, &stream);
133 if (status != PSA_SUCCESS) {
134 goto exit;
135 }
136 status = PSA_ERROR_INVALID_ARGUMENT;
137 if (data_offset + data_length < data_offset) {
138 goto exit;
139 }
140 #if SIZE_MAX < 0xffffffff
141 if (data_offset + data_length > SIZE_MAX) {
142 goto exit;
143 }
144 #endif
145 if (data_offset + data_length > info.size) {
146 goto exit;
147 }
148
149 status = PSA_ERROR_STORAGE_FAILURE;
150 #if LONG_MAX < 0xffffffff
151 while (data_offset > LONG_MAX) {
152 if (fseek(stream, LONG_MAX, SEEK_CUR) != 0) {
153 goto exit;
154 }
155 data_offset -= LONG_MAX;
156 }
157 #endif
158 if (fseek(stream, data_offset, SEEK_CUR) != 0) {
159 goto exit;
160 }
161 n = fread(p_data, 1, data_length, stream);
162 if (n != data_length) {
163 goto exit;
164 }
165 status = PSA_SUCCESS;
166 if (p_data_length != NULL) {
167 *p_data_length = n;
168 }
169
170 exit:
171 if (stream != NULL) {
172 fclose(stream);
173 }
174 return status;
175 }
176
psa_its_set(psa_storage_uid_t uid,uint32_t data_length,const void * p_data,psa_storage_create_flags_t create_flags)177 psa_status_t psa_its_set(psa_storage_uid_t uid,
178 uint32_t data_length,
179 const void *p_data,
180 psa_storage_create_flags_t create_flags)
181 {
182 if (uid == 0) {
183 return PSA_ERROR_INVALID_HANDLE;
184 }
185
186 psa_status_t status = PSA_ERROR_STORAGE_FAILURE;
187 char filename[PSA_ITS_STORAGE_FILENAME_LENGTH];
188 FILE *stream = NULL;
189 psa_its_file_header_t header;
190 size_t n;
191
192 memcpy(header.magic, PSA_ITS_MAGIC_STRING, PSA_ITS_MAGIC_LENGTH);
193 MBEDTLS_PUT_UINT32_LE(data_length, header.size, 0);
194 MBEDTLS_PUT_UINT32_LE(create_flags, header.flags, 0);
195
196 psa_its_fill_filename(uid, filename);
197 stream = fopen(PSA_ITS_STORAGE_TEMP, "wb");
198 if (stream == NULL) {
199 goto exit;
200 }
201
202 status = PSA_ERROR_INSUFFICIENT_STORAGE;
203 n = fwrite(&header, 1, sizeof(header), stream);
204 if (n != sizeof(header)) {
205 goto exit;
206 }
207 if (data_length != 0) {
208 n = fwrite(p_data, 1, data_length, stream);
209 if (n != data_length) {
210 goto exit;
211 }
212 }
213 status = PSA_SUCCESS;
214
215 exit:
216 if (stream != NULL) {
217 int ret = fclose(stream);
218 if (status == PSA_SUCCESS && ret != 0) {
219 status = PSA_ERROR_INSUFFICIENT_STORAGE;
220 }
221 }
222 if (status == PSA_SUCCESS) {
223 if (rename_replace_existing(PSA_ITS_STORAGE_TEMP, filename) != 0) {
224 status = PSA_ERROR_STORAGE_FAILURE;
225 }
226 }
227 /* The temporary file may still exist, but only in failure cases where
228 * we're already reporting an error. So there's nothing we can do on
229 * failure. If the function succeeded, and in some error cases, the
230 * temporary file doesn't exist and so remove() is expected to fail.
231 * Thus we just ignore the return status of remove(). */
232 (void) remove(PSA_ITS_STORAGE_TEMP);
233 return status;
234 }
235
psa_its_remove(psa_storage_uid_t uid)236 psa_status_t psa_its_remove(psa_storage_uid_t uid)
237 {
238 char filename[PSA_ITS_STORAGE_FILENAME_LENGTH];
239 FILE *stream;
240 psa_its_fill_filename(uid, filename);
241 stream = fopen(filename, "rb");
242 if (stream == NULL) {
243 return PSA_ERROR_DOES_NOT_EXIST;
244 }
245 fclose(stream);
246 if (remove(filename) != 0) {
247 return PSA_ERROR_STORAGE_FAILURE;
248 }
249 return PSA_SUCCESS;
250 }
251
252 #endif /* MBEDTLS_PSA_ITS_FILE_C */
253