1 /*
2  *  PKCS#12 Personal Information Exchange Syntax
3  *
4  *  Copyright The Mbed TLS Contributors
5  *  SPDX-License-Identifier: Apache-2.0 OR GPL-2.0-or-later
6  */
7 /*
8  *  The PKCS #12 Personal Information Exchange Syntax Standard v1.1
9  *
10  *  http://www.rsa.com/rsalabs/pkcs/files/h11301-wp-pkcs-12v1-1-personal-information-exchange-syntax.pdf
11  *  ftp://ftp.rsasecurity.com/pub/pkcs/pkcs-12/pkcs-12v1-1.asn
12  */
13 
14 #include "common.h"
15 
16 #if defined(MBEDTLS_PKCS12_C)
17 
18 #include "mbedtls/pkcs12.h"
19 #include "mbedtls/asn1.h"
20 #if defined(MBEDTLS_CIPHER_C)
21 #include "mbedtls/cipher.h"
22 #endif /* MBEDTLS_CIPHER_C */
23 #include "mbedtls/platform_util.h"
24 #include "mbedtls/error.h"
25 
26 #include <string.h>
27 
28 #if defined(MBEDTLS_DES_C)
29 #include "mbedtls/des.h"
30 #endif
31 
32 #include "psa_util_internal.h"
33 
34 #if defined(MBEDTLS_ASN1_PARSE_C) && defined(MBEDTLS_CIPHER_C)
35 
pkcs12_parse_pbe_params(mbedtls_asn1_buf * params,mbedtls_asn1_buf * salt,int * iterations)36 static int pkcs12_parse_pbe_params(mbedtls_asn1_buf *params,
37                                    mbedtls_asn1_buf *salt, int *iterations)
38 {
39     int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
40     unsigned char **p = &params->p;
41     const unsigned char *end = params->p + params->len;
42 
43     /*
44      *  pkcs-12PbeParams ::= SEQUENCE {
45      *    salt          OCTET STRING,
46      *    iterations    INTEGER
47      *  }
48      *
49      */
50     if (params->tag != (MBEDTLS_ASN1_CONSTRUCTED | MBEDTLS_ASN1_SEQUENCE)) {
51         return MBEDTLS_ERROR_ADD(MBEDTLS_ERR_PKCS12_PBE_INVALID_FORMAT,
52                                  MBEDTLS_ERR_ASN1_UNEXPECTED_TAG);
53     }
54 
55     if ((ret = mbedtls_asn1_get_tag(p, end, &salt->len, MBEDTLS_ASN1_OCTET_STRING)) != 0) {
56         return MBEDTLS_ERROR_ADD(MBEDTLS_ERR_PKCS12_PBE_INVALID_FORMAT, ret);
57     }
58 
59     salt->p = *p;
60     *p += salt->len;
61 
62     if ((ret = mbedtls_asn1_get_int(p, end, iterations)) != 0) {
63         return MBEDTLS_ERROR_ADD(MBEDTLS_ERR_PKCS12_PBE_INVALID_FORMAT, ret);
64     }
65 
66     if (*p != end) {
67         return MBEDTLS_ERROR_ADD(MBEDTLS_ERR_PKCS12_PBE_INVALID_FORMAT,
68                                  MBEDTLS_ERR_ASN1_LENGTH_MISMATCH);
69     }
70 
71     return 0;
72 }
73 
74 #define PKCS12_MAX_PWDLEN 128
75 
pkcs12_pbe_derive_key_iv(mbedtls_asn1_buf * pbe_params,mbedtls_md_type_t md_type,const unsigned char * pwd,size_t pwdlen,unsigned char * key,size_t keylen,unsigned char * iv,size_t ivlen)76 static int pkcs12_pbe_derive_key_iv(mbedtls_asn1_buf *pbe_params, mbedtls_md_type_t md_type,
77                                     const unsigned char *pwd,  size_t pwdlen,
78                                     unsigned char *key, size_t keylen,
79                                     unsigned char *iv,  size_t ivlen)
80 {
81     int ret, iterations = 0;
82     mbedtls_asn1_buf salt;
83     size_t i;
84     unsigned char unipwd[PKCS12_MAX_PWDLEN * 2 + 2];
85 
86     if (pwdlen > PKCS12_MAX_PWDLEN) {
87         return MBEDTLS_ERR_PKCS12_BAD_INPUT_DATA;
88     }
89 
90     memset(&salt, 0, sizeof(mbedtls_asn1_buf));
91     memset(&unipwd, 0, sizeof(unipwd));
92 
93     if ((ret = pkcs12_parse_pbe_params(pbe_params, &salt,
94                                        &iterations)) != 0) {
95         return ret;
96     }
97 
98     for (i = 0; i < pwdlen; i++) {
99         unipwd[i * 2 + 1] = pwd[i];
100     }
101 
102     if ((ret = mbedtls_pkcs12_derivation(key, keylen, unipwd, pwdlen * 2 + 2,
103                                          salt.p, salt.len, md_type,
104                                          MBEDTLS_PKCS12_DERIVE_KEY, iterations)) != 0) {
105         return ret;
106     }
107 
108     if (iv == NULL || ivlen == 0) {
109         return 0;
110     }
111 
112     if ((ret = mbedtls_pkcs12_derivation(iv, ivlen, unipwd, pwdlen * 2 + 2,
113                                          salt.p, salt.len, md_type,
114                                          MBEDTLS_PKCS12_DERIVE_IV, iterations)) != 0) {
115         return ret;
116     }
117     return 0;
118 }
119 
120 #undef PKCS12_MAX_PWDLEN
121 
122 #if !defined(MBEDTLS_CIPHER_PADDING_PKCS7)
123 int mbedtls_pkcs12_pbe_ext(mbedtls_asn1_buf *pbe_params, int mode,
124                            mbedtls_cipher_type_t cipher_type, mbedtls_md_type_t md_type,
125                            const unsigned char *pwd,  size_t pwdlen,
126                            const unsigned char *data, size_t len,
127                            unsigned char *output, size_t output_size,
128                            size_t *output_len);
129 #endif
130 
131 #if !defined(MBEDTLS_DEPRECATED_REMOVED)
mbedtls_pkcs12_pbe(mbedtls_asn1_buf * pbe_params,int mode,mbedtls_cipher_type_t cipher_type,mbedtls_md_type_t md_type,const unsigned char * pwd,size_t pwdlen,const unsigned char * data,size_t len,unsigned char * output)132 int mbedtls_pkcs12_pbe(mbedtls_asn1_buf *pbe_params, int mode,
133                        mbedtls_cipher_type_t cipher_type, mbedtls_md_type_t md_type,
134                        const unsigned char *pwd,  size_t pwdlen,
135                        const unsigned char *data, size_t len,
136                        unsigned char *output)
137 {
138     size_t output_len = 0;
139 
140     /* We assume caller of the function is providing a big enough output buffer
141      * so we pass output_size as SIZE_MAX to pass checks, However, no guarantees
142      * for the output size actually being correct.
143      */
144     return mbedtls_pkcs12_pbe_ext(pbe_params, mode, cipher_type, md_type,
145                                   pwd, pwdlen, data, len, output, SIZE_MAX,
146                                   &output_len);
147 }
148 #endif
149 
mbedtls_pkcs12_pbe_ext(mbedtls_asn1_buf * pbe_params,int mode,mbedtls_cipher_type_t cipher_type,mbedtls_md_type_t md_type,const unsigned char * pwd,size_t pwdlen,const unsigned char * data,size_t len,unsigned char * output,size_t output_size,size_t * output_len)150 int mbedtls_pkcs12_pbe_ext(mbedtls_asn1_buf *pbe_params, int mode,
151                            mbedtls_cipher_type_t cipher_type, mbedtls_md_type_t md_type,
152                            const unsigned char *pwd,  size_t pwdlen,
153                            const unsigned char *data, size_t len,
154                            unsigned char *output, size_t output_size,
155                            size_t *output_len)
156 {
157     int ret, keylen = 0;
158     unsigned char key[32];
159     unsigned char iv[16];
160     const mbedtls_cipher_info_t *cipher_info;
161     mbedtls_cipher_context_t cipher_ctx;
162     size_t iv_len = 0;
163     size_t finish_olen = 0;
164     unsigned int padlen = 0;
165 
166     if (pwd == NULL && pwdlen != 0) {
167         return MBEDTLS_ERR_PKCS12_BAD_INPUT_DATA;
168     }
169 
170     cipher_info = mbedtls_cipher_info_from_type(cipher_type);
171     if (cipher_info == NULL) {
172         return MBEDTLS_ERR_PKCS12_FEATURE_UNAVAILABLE;
173     }
174 
175     keylen = (int) mbedtls_cipher_info_get_key_bitlen(cipher_info) / 8;
176 
177     if (mode == MBEDTLS_PKCS12_PBE_DECRYPT) {
178         if (output_size < len) {
179             return MBEDTLS_ERR_ASN1_BUF_TOO_SMALL;
180         }
181     }
182 
183     if (mode == MBEDTLS_PKCS12_PBE_ENCRYPT) {
184         padlen = cipher_info->block_size - (len % cipher_info->block_size);
185         if (output_size < (len + padlen)) {
186             return MBEDTLS_ERR_ASN1_BUF_TOO_SMALL;
187         }
188     }
189 
190     iv_len = mbedtls_cipher_info_get_iv_size(cipher_info);
191     if ((ret = pkcs12_pbe_derive_key_iv(pbe_params, md_type, pwd, pwdlen,
192                                         key, keylen,
193                                         iv, iv_len)) != 0) {
194         return ret;
195     }
196 
197     mbedtls_cipher_init(&cipher_ctx);
198 
199     if ((ret = mbedtls_cipher_setup(&cipher_ctx, cipher_info)) != 0) {
200         goto exit;
201     }
202 
203     if ((ret = mbedtls_cipher_setkey(&cipher_ctx, key, 8 * keylen,
204                                      (mbedtls_operation_t) mode)) != 0) {
205         goto exit;
206     }
207 
208 #if defined(MBEDTLS_CIPHER_MODE_WITH_PADDING)
209     {
210         /* PKCS12 uses CBC with PKCS7 padding */
211         mbedtls_cipher_padding_t padding = MBEDTLS_PADDING_PKCS7;
212 #if !defined(MBEDTLS_CIPHER_PADDING_PKCS7)
213         /* For historical reasons, when decrypting, this function works when
214          * decrypting even when support for PKCS7 padding is disabled. In this
215          * case, it ignores the padding, and so will never report a
216          * password mismatch.
217          */
218         if (mode == MBEDTLS_PKCS12_PBE_DECRYPT) {
219             padding = MBEDTLS_PADDING_NONE;
220         }
221 #endif
222         if ((ret = mbedtls_cipher_set_padding_mode(&cipher_ctx, padding)) != 0) {
223             goto exit;
224         }
225     }
226 #endif /* MBEDTLS_CIPHER_MODE_WITH_PADDING */
227 
228     ret = mbedtls_cipher_crypt(&cipher_ctx, iv, iv_len, data, len, output, &finish_olen);
229     if (ret == MBEDTLS_ERR_CIPHER_INVALID_PADDING) {
230         ret = MBEDTLS_ERR_PKCS12_PASSWORD_MISMATCH;
231     }
232 
233     *output_len += finish_olen;
234 
235 exit:
236     mbedtls_platform_zeroize(key, sizeof(key));
237     mbedtls_platform_zeroize(iv,  sizeof(iv));
238     mbedtls_cipher_free(&cipher_ctx);
239 
240     return ret;
241 }
242 
243 #endif /* MBEDTLS_ASN1_PARSE_C && MBEDTLS_CIPHER_C */
244 
pkcs12_fill_buffer(unsigned char * data,size_t data_len,const unsigned char * filler,size_t fill_len)245 static void pkcs12_fill_buffer(unsigned char *data, size_t data_len,
246                                const unsigned char *filler, size_t fill_len)
247 {
248     unsigned char *p = data;
249     size_t use_len;
250 
251     if (filler != NULL && fill_len != 0) {
252         while (data_len > 0) {
253             use_len = (data_len > fill_len) ? fill_len : data_len;
254             memcpy(p, filler, use_len);
255             p += use_len;
256             data_len -= use_len;
257         }
258     } else {
259         /* If either of the above are not true then clearly there is nothing
260          * that this function can do. The function should *not* be called
261          * under either of those circumstances, as you could end up with an
262          * incorrect output but for safety's sake, leaving the check in as
263          * otherwise we could end up with memory corruption.*/
264     }
265 }
266 
267 
calculate_hashes(mbedtls_md_type_t md_type,int iterations,unsigned char * diversifier,unsigned char * salt_block,unsigned char * pwd_block,unsigned char * hash_output,int use_salt,int use_password,size_t hlen,size_t v)268 static int calculate_hashes(mbedtls_md_type_t md_type, int iterations,
269                             unsigned char *diversifier, unsigned char *salt_block,
270                             unsigned char *pwd_block, unsigned char *hash_output, int use_salt,
271                             int use_password, size_t hlen, size_t v)
272 {
273     int ret = -1;
274     size_t i;
275     const mbedtls_md_info_t *md_info;
276     mbedtls_md_context_t md_ctx;
277     md_info = mbedtls_md_info_from_type(md_type);
278     if (md_info == NULL) {
279         return MBEDTLS_ERR_PKCS12_FEATURE_UNAVAILABLE;
280     }
281 
282     mbedtls_md_init(&md_ctx);
283 
284     if ((ret = mbedtls_md_setup(&md_ctx, md_info, 0)) != 0) {
285         return ret;
286     }
287     // Calculate hash( diversifier || salt_block || pwd_block )
288     if ((ret = mbedtls_md_starts(&md_ctx)) != 0) {
289         goto exit;
290     }
291 
292     if ((ret = mbedtls_md_update(&md_ctx, diversifier, v)) != 0) {
293         goto exit;
294     }
295 
296     if (use_salt != 0) {
297         if ((ret = mbedtls_md_update(&md_ctx, salt_block, v)) != 0) {
298             goto exit;
299         }
300     }
301 
302     if (use_password != 0) {
303         if ((ret = mbedtls_md_update(&md_ctx, pwd_block, v)) != 0) {
304             goto exit;
305         }
306     }
307 
308     if ((ret = mbedtls_md_finish(&md_ctx, hash_output)) != 0) {
309         goto exit;
310     }
311 
312     // Perform remaining ( iterations - 1 ) recursive hash calculations
313     for (i = 1; i < (size_t) iterations; i++) {
314         if ((ret = mbedtls_md(md_info, hash_output, hlen, hash_output))
315             != 0) {
316             goto exit;
317         }
318     }
319 
320 exit:
321     mbedtls_md_free(&md_ctx);
322     return ret;
323 }
324 
325 
mbedtls_pkcs12_derivation(unsigned char * data,size_t datalen,const unsigned char * pwd,size_t pwdlen,const unsigned char * salt,size_t saltlen,mbedtls_md_type_t md_type,int id,int iterations)326 int mbedtls_pkcs12_derivation(unsigned char *data, size_t datalen,
327                               const unsigned char *pwd, size_t pwdlen,
328                               const unsigned char *salt, size_t saltlen,
329                               mbedtls_md_type_t md_type, int id, int iterations)
330 {
331     int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
332     unsigned int j;
333 
334     unsigned char diversifier[128];
335     unsigned char salt_block[128], pwd_block[128], hash_block[128] = { 0 };
336     unsigned char hash_output[MBEDTLS_MD_MAX_SIZE];
337     unsigned char *p;
338     unsigned char c;
339     int           use_password = 0;
340     int           use_salt = 0;
341 
342     size_t hlen, use_len, v, i;
343 
344     // This version only allows max of 64 bytes of password or salt
345     if (datalen > 128 || pwdlen > 64 || saltlen > 64) {
346         return MBEDTLS_ERR_PKCS12_BAD_INPUT_DATA;
347     }
348 
349     if (pwd == NULL && pwdlen != 0) {
350         return MBEDTLS_ERR_PKCS12_BAD_INPUT_DATA;
351     }
352 
353     if (salt == NULL && saltlen != 0) {
354         return MBEDTLS_ERR_PKCS12_BAD_INPUT_DATA;
355     }
356 
357     use_password = (pwd && pwdlen != 0);
358     use_salt = (salt && saltlen != 0);
359 
360     hlen = mbedtls_md_get_size_from_type(md_type);
361 
362     if (hlen <= 32) {
363         v = 64;
364     } else {
365         v = 128;
366     }
367 
368     memset(diversifier, (unsigned char) id, v);
369 
370     if (use_salt != 0) {
371         pkcs12_fill_buffer(salt_block, v, salt, saltlen);
372     }
373 
374     if (use_password != 0) {
375         pkcs12_fill_buffer(pwd_block,  v, pwd,  pwdlen);
376     }
377 
378     p = data;
379     while (datalen > 0) {
380         if (calculate_hashes(md_type, iterations, diversifier, salt_block,
381                              pwd_block, hash_output, use_salt, use_password, hlen,
382                              v) != 0) {
383             goto exit;
384         }
385 
386         use_len = (datalen > hlen) ? hlen : datalen;
387         memcpy(p, hash_output, use_len);
388         datalen -= use_len;
389         p += use_len;
390 
391         if (datalen == 0) {
392             break;
393         }
394 
395         // Concatenating copies of hash_output into hash_block (B)
396         pkcs12_fill_buffer(hash_block, v, hash_output, hlen);
397 
398         // B += 1
399         for (i = v; i > 0; i--) {
400             if (++hash_block[i - 1] != 0) {
401                 break;
402             }
403         }
404 
405         if (use_salt != 0) {
406             // salt_block += B
407             c = 0;
408             for (i = v; i > 0; i--) {
409                 j = salt_block[i - 1] + hash_block[i - 1] + c;
410                 c = MBEDTLS_BYTE_1(j);
411                 salt_block[i - 1] = MBEDTLS_BYTE_0(j);
412             }
413         }
414 
415         if (use_password != 0) {
416             // pwd_block  += B
417             c = 0;
418             for (i = v; i > 0; i--) {
419                 j = pwd_block[i - 1] + hash_block[i - 1] + c;
420                 c = MBEDTLS_BYTE_1(j);
421                 pwd_block[i - 1] = MBEDTLS_BYTE_0(j);
422             }
423         }
424     }
425 
426     ret = 0;
427 
428 exit:
429     mbedtls_platform_zeroize(salt_block, sizeof(salt_block));
430     mbedtls_platform_zeroize(pwd_block, sizeof(pwd_block));
431     mbedtls_platform_zeroize(hash_block, sizeof(hash_block));
432     mbedtls_platform_zeroize(hash_output, sizeof(hash_output));
433 
434     return ret;
435 }
436 
437 #endif /* MBEDTLS_PKCS12_C */
438