1 /**
2  * \file psa/crypto_struct.h
3  *
4  * \brief PSA cryptography module: Mbed TLS structured type implementations
5  *
6  * \note This file may not be included directly. Applications must
7  * include psa/crypto.h.
8  *
9  * This file contains the definitions of some data structures with
10  * implementation-specific definitions.
11  *
12  * In implementations with isolation between the application and the
13  * cryptography module, it is expected that the front-end and the back-end
14  * would have different versions of this file.
15  *
16  * <h3>Design notes about multipart operation structures</h3>
17  *
18  * Each multipart operation structure contains a `psa_algorithm_t alg`
19  * field which indicates which specific algorithm the structure is for.
20  * When the structure is not in use, `alg` is 0. Most of the structure
21  * consists of a union which is discriminated by `alg`.
22  *
23  * Note that when `alg` is 0, the content of other fields is undefined.
24  * In particular, it is not guaranteed that a freshly-initialized structure
25  * is all-zero: we initialize structures to something like `{0, 0}`, which
26  * is only guaranteed to initializes the first member of the union;
27  * GCC and Clang initialize the whole structure to 0 (at the time of writing),
28  * but MSVC and CompCert don't.
29  *
30  * In Mbed Crypto, multipart operation structures live independently from
31  * the key. This allows Mbed Crypto to free the key objects when destroying
32  * a key slot. If a multipart operation needs to remember the key after
33  * the setup function returns, the operation structure needs to contain a
34  * copy of the key.
35  */
36 /*
37  *  Copyright The Mbed TLS Contributors
38  *  SPDX-License-Identifier: Apache-2.0
39  *
40  *  Licensed under the Apache License, Version 2.0 (the "License"); you may
41  *  not use this file except in compliance with the License.
42  *  You may obtain a copy of the License at
43  *
44  *  http://www.apache.org/licenses/LICENSE-2.0
45  *
46  *  Unless required by applicable law or agreed to in writing, software
47  *  distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
48  *  WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
49  *  See the License for the specific language governing permissions and
50  *  limitations under the License.
51  */
52 
53 #ifndef PSA_CRYPTO_STRUCT_H
54 #define PSA_CRYPTO_STRUCT_H
55 
56 #ifdef __cplusplus
57 extern "C" {
58 #endif
59 
60 /* Include the Mbed TLS configuration file, the way Mbed TLS does it
61  * in each of its header files. */
62 #if !defined(MBEDTLS_CONFIG_FILE)
63 #include "mbedtls/config.h"
64 #else
65 #include MBEDTLS_CONFIG_FILE
66 #endif
67 
68 #include "mbedtls/cipher.h"
69 #include "mbedtls/cmac.h"
70 #include "mbedtls/gcm.h"
71 #include "mbedtls/md.h"
72 #include "mbedtls/md2.h"
73 #include "mbedtls/md4.h"
74 #include "mbedtls/md5.h"
75 #include "mbedtls/ripemd160.h"
76 #include "mbedtls/sha1.h"
77 #include "mbedtls/sha256.h"
78 #include "mbedtls/sha512.h"
79 
80 typedef struct {
81     /** Unique ID indicating which driver got assigned to do the
82      * operation. Since driver contexts are driver-specific, swapping
83      * drivers halfway through the operation is not supported.
84      * ID values are auto-generated in psa_driver_wrappers.h */
85     unsigned int id;
86     /** Context structure for the assigned driver, when id is not zero. */
87     void* ctx;
88 } psa_operation_driver_context_t;
89 
90 struct psa_hash_operation_s
91 {
92     psa_algorithm_t alg;
93     union
94     {
95         unsigned dummy; /* Make the union non-empty even with no supported algorithms. */
96 #if defined(MBEDTLS_MD2_C)
97         mbedtls_md2_context md2;
98 #endif
99 #if defined(MBEDTLS_MD4_C)
100         mbedtls_md4_context md4;
101 #endif
102 #if defined(MBEDTLS_MD5_C)
103         mbedtls_md5_context md5;
104 #endif
105 #if defined(MBEDTLS_RIPEMD160_C)
106         mbedtls_ripemd160_context ripemd160;
107 #endif
108 #if defined(MBEDTLS_SHA1_C)
109         mbedtls_sha1_context sha1;
110 #endif
111 #if defined(MBEDTLS_SHA256_C)
112         mbedtls_sha256_context sha256;
113 #endif
114 #if defined(MBEDTLS_SHA512_C)
115         mbedtls_sha512_context sha512;
116 #endif
117     } ctx;
118 };
119 
120 #define PSA_HASH_OPERATION_INIT {0, {0}}
psa_hash_operation_init(void)121 static inline struct psa_hash_operation_s psa_hash_operation_init( void )
122 {
123     const struct psa_hash_operation_s v = PSA_HASH_OPERATION_INIT;
124     return( v );
125 }
126 
127 #if defined(MBEDTLS_MD_C)
128 typedef struct
129 {
130         /** The hash context. */
131         struct psa_hash_operation_s hash_ctx;
132         /** The HMAC part of the context. */
133         uint8_t opad[PSA_HMAC_MAX_HASH_BLOCK_SIZE];
134 } psa_hmac_internal_data;
135 #endif /* MBEDTLS_MD_C */
136 
137 struct psa_mac_operation_s
138 {
139     psa_algorithm_t alg;
140     unsigned int key_set : 1;
141     unsigned int iv_required : 1;
142     unsigned int iv_set : 1;
143     unsigned int has_input : 1;
144     unsigned int is_sign : 1;
145     uint8_t mac_size;
146     union
147     {
148         unsigned dummy; /* Make the union non-empty even with no supported algorithms. */
149 #if defined(MBEDTLS_MD_C)
150         psa_hmac_internal_data hmac;
151 #endif
152 #if defined(MBEDTLS_CMAC_C)
153         mbedtls_cipher_context_t cmac;
154 #endif
155     } ctx;
156 };
157 
158 #define PSA_MAC_OPERATION_INIT {0, 0, 0, 0, 0, 0, 0, {0}}
psa_mac_operation_init(void)159 static inline struct psa_mac_operation_s psa_mac_operation_init( void )
160 {
161     const struct psa_mac_operation_s v = PSA_MAC_OPERATION_INIT;
162     return( v );
163 }
164 
165 struct psa_cipher_operation_s
166 {
167     psa_algorithm_t alg;
168     unsigned int key_set : 1;
169     unsigned int iv_required : 1;
170     unsigned int iv_set : 1;
171     unsigned int mbedtls_in_use : 1; /* Indicates mbed TLS is handling the operation. */
172     uint8_t iv_size;
173     uint8_t block_size;
174     union
175     {
176         unsigned dummy; /* Enable easier initializing of the union. */
177         mbedtls_cipher_context_t cipher;
178         psa_operation_driver_context_t driver;
179     } ctx;
180 };
181 
182 #define PSA_CIPHER_OPERATION_INIT {0, 0, 0, 0, 0, 0, 0, {0}}
psa_cipher_operation_init(void)183 static inline struct psa_cipher_operation_s psa_cipher_operation_init( void )
184 {
185     const struct psa_cipher_operation_s v = PSA_CIPHER_OPERATION_INIT;
186     return( v );
187 }
188 
189 struct psa_aead_operation_s
190 {
191     psa_algorithm_t alg;
192     unsigned int key_set : 1;
193     unsigned int iv_set : 1;
194     uint8_t iv_size;
195     uint8_t block_size;
196     union
197     {
198         unsigned dummy; /* Enable easier initializing of the union. */
199         mbedtls_cipher_context_t cipher;
200     } ctx;
201 };
202 
203 #define PSA_AEAD_OPERATION_INIT {0, 0, 0, 0, 0, {0}}
psa_aead_operation_init(void)204 static inline struct psa_aead_operation_s psa_aead_operation_init( void )
205 {
206     const struct psa_aead_operation_s v = PSA_AEAD_OPERATION_INIT;
207     return( v );
208 }
209 
210 #if defined(MBEDTLS_MD_C)
211 typedef struct
212 {
213     uint8_t *info;
214     size_t info_length;
215     psa_hmac_internal_data hmac;
216     uint8_t prk[PSA_HASH_MAX_SIZE];
217     uint8_t output_block[PSA_HASH_MAX_SIZE];
218 #if PSA_HASH_MAX_SIZE > 0xff
219 #error "PSA_HASH_MAX_SIZE does not fit in uint8_t"
220 #endif
221     uint8_t offset_in_block;
222     uint8_t block_number;
223     unsigned int state : 2;
224     unsigned int info_set : 1;
225 } psa_hkdf_key_derivation_t;
226 #endif /* MBEDTLS_MD_C */
227 
228 #if defined(MBEDTLS_MD_C)
229 typedef enum
230 {
231     TLS12_PRF_STATE_INIT,       /* no input provided */
232     TLS12_PRF_STATE_SEED_SET,   /* seed has been set */
233     TLS12_PRF_STATE_KEY_SET,    /* key has been set */
234     TLS12_PRF_STATE_LABEL_SET,  /* label has been set */
235     TLS12_PRF_STATE_OUTPUT      /* output has been started */
236 } psa_tls12_prf_key_derivation_state_t;
237 
238 typedef struct psa_tls12_prf_key_derivation_s
239 {
240 #if PSA_HASH_MAX_SIZE > 0xff
241 #error "PSA_HASH_MAX_SIZE does not fit in uint8_t"
242 #endif
243 
244     /* Indicates how many bytes in the current HMAC block have
245      * not yet been read by the user. */
246     uint8_t left_in_block;
247 
248     /* The 1-based number of the block. */
249     uint8_t block_number;
250 
251     psa_tls12_prf_key_derivation_state_t state;
252 
253     uint8_t *seed;
254     size_t seed_length;
255     uint8_t *label;
256     size_t label_length;
257     psa_hmac_internal_data hmac;
258     uint8_t Ai[PSA_HASH_MAX_SIZE];
259 
260     /* `HMAC_hash( prk, A(i) + seed )` in the notation of RFC 5246, Sect. 5. */
261     uint8_t output_block[PSA_HASH_MAX_SIZE];
262 } psa_tls12_prf_key_derivation_t;
263 #endif /* MBEDTLS_MD_C */
264 
265 struct psa_key_derivation_s
266 {
267     psa_algorithm_t alg;
268     unsigned int can_output_key : 1;
269     size_t capacity;
270     union
271     {
272         /* Make the union non-empty even with no supported algorithms. */
273         uint8_t dummy;
274 #if defined(MBEDTLS_MD_C)
275         psa_hkdf_key_derivation_t hkdf;
276         psa_tls12_prf_key_derivation_t tls12_prf;
277 #endif
278     } ctx;
279 };
280 
281 /* This only zeroes out the first byte in the union, the rest is unspecified. */
282 #define PSA_KEY_DERIVATION_OPERATION_INIT {0, 0, 0, {0}}
psa_key_derivation_operation_init(void)283 static inline struct psa_key_derivation_s psa_key_derivation_operation_init( void )
284 {
285     const struct psa_key_derivation_s v = PSA_KEY_DERIVATION_OPERATION_INIT;
286     return( v );
287 }
288 
289 struct psa_key_policy_s
290 {
291     psa_key_usage_t usage;
292     psa_algorithm_t alg;
293     psa_algorithm_t alg2;
294 };
295 typedef struct psa_key_policy_s psa_key_policy_t;
296 
297 #define PSA_KEY_POLICY_INIT {0, 0, 0}
psa_key_policy_init(void)298 static inline struct psa_key_policy_s psa_key_policy_init( void )
299 {
300     const struct psa_key_policy_s v = PSA_KEY_POLICY_INIT;
301     return( v );
302 }
303 
304 /* The type used internally for key sizes.
305  * Public interfaces use size_t, but internally we use a smaller type. */
306 typedef uint16_t psa_key_bits_t;
307 /* The maximum value of the type used to represent bit-sizes.
308  * This is used to mark an invalid key size. */
309 #define PSA_KEY_BITS_TOO_LARGE ( (psa_key_bits_t) ( -1 ) )
310 /* The maximum size of a key in bits.
311  * Currently defined as the maximum that can be represented, rounded down
312  * to a whole number of bytes.
313  * This is an uncast value so that it can be used in preprocessor
314  * conditionals. */
315 #define PSA_MAX_KEY_BITS 0xfff8
316 
317 /** A mask of flags that can be stored in key attributes.
318  *
319  * This type is also used internally to store flags in slots. Internal
320  * flags are defined in library/psa_crypto_core.h. Internal flags may have
321  * the same value as external flags if they are properly handled during
322  * key creation and in psa_get_key_attributes.
323  */
324 typedef uint16_t psa_key_attributes_flag_t;
325 
326 #define MBEDTLS_PSA_KA_FLAG_HAS_SLOT_NUMBER     \
327     ( (psa_key_attributes_flag_t) 0x0001 )
328 
329 /* A mask of key attribute flags used externally only.
330  * Only meant for internal checks inside the library. */
331 #define MBEDTLS_PSA_KA_MASK_EXTERNAL_ONLY (      \
332         MBEDTLS_PSA_KA_FLAG_HAS_SLOT_NUMBER |    \
333         0 )
334 
335 /* A mask of key attribute flags used both internally and externally.
336  * Currently there aren't any. */
337 #define MBEDTLS_PSA_KA_MASK_DUAL_USE (          \
338         0 )
339 
340 typedef struct
341 {
342     psa_key_type_t type;
343     psa_key_bits_t bits;
344     psa_key_lifetime_t lifetime;
345     mbedtls_svc_key_id_t id;
346     psa_key_policy_t policy;
347     psa_key_attributes_flag_t flags;
348 } psa_core_key_attributes_t;
349 
350 #define PSA_CORE_KEY_ATTRIBUTES_INIT {PSA_KEY_TYPE_NONE, 0, PSA_KEY_LIFETIME_VOLATILE, MBEDTLS_SVC_KEY_ID_INIT, PSA_KEY_POLICY_INIT, 0}
351 
352 struct psa_key_attributes_s
353 {
354     psa_core_key_attributes_t core;
355 #if defined(MBEDTLS_PSA_CRYPTO_SE_C)
356     psa_key_slot_number_t slot_number;
357 #endif /* MBEDTLS_PSA_CRYPTO_SE_C */
358     void *domain_parameters;
359     size_t domain_parameters_size;
360 };
361 
362 #if defined(MBEDTLS_PSA_CRYPTO_SE_C)
363 #define PSA_KEY_ATTRIBUTES_INIT {PSA_CORE_KEY_ATTRIBUTES_INIT, 0, NULL, 0}
364 #else
365 #define PSA_KEY_ATTRIBUTES_INIT {PSA_CORE_KEY_ATTRIBUTES_INIT, NULL, 0}
366 #endif
367 
psa_key_attributes_init(void)368 static inline struct psa_key_attributes_s psa_key_attributes_init( void )
369 {
370     const struct psa_key_attributes_s v = PSA_KEY_ATTRIBUTES_INIT;
371     return( v );
372 }
373 
psa_set_key_id(psa_key_attributes_t * attributes,mbedtls_svc_key_id_t key)374 static inline void psa_set_key_id( psa_key_attributes_t *attributes,
375                                    mbedtls_svc_key_id_t key )
376 {
377     psa_key_lifetime_t lifetime = attributes->core.lifetime;
378 
379     attributes->core.id = key;
380 
381     if( PSA_KEY_LIFETIME_IS_VOLATILE( lifetime ) )
382     {
383         attributes->core.lifetime =
384             PSA_KEY_LIFETIME_FROM_PERSISTENCE_AND_LOCATION(
385                 PSA_KEY_LIFETIME_PERSISTENT,
386                 PSA_KEY_LIFETIME_GET_LOCATION( lifetime ) );
387     }
388 }
389 
psa_get_key_id(const psa_key_attributes_t * attributes)390 static inline mbedtls_svc_key_id_t psa_get_key_id(
391     const psa_key_attributes_t *attributes)
392 {
393     return( attributes->core.id );
394 }
395 
396 #ifdef MBEDTLS_PSA_CRYPTO_KEY_ID_ENCODES_OWNER
mbedtls_set_key_owner_id(psa_key_attributes_t * attributes,mbedtls_key_owner_id_t owner)397 static inline void mbedtls_set_key_owner_id( psa_key_attributes_t *attributes,
398                                              mbedtls_key_owner_id_t owner )
399 {
400     attributes->core.id.owner = owner;
401 }
402 #endif
403 
psa_set_key_lifetime(psa_key_attributes_t * attributes,psa_key_lifetime_t lifetime)404 static inline void psa_set_key_lifetime(psa_key_attributes_t *attributes,
405                                         psa_key_lifetime_t lifetime)
406 {
407     attributes->core.lifetime = lifetime;
408     if( PSA_KEY_LIFETIME_IS_VOLATILE( lifetime ) )
409     {
410 #ifdef MBEDTLS_PSA_CRYPTO_KEY_ID_ENCODES_OWNER
411         attributes->core.id.key_id = 0;
412 #else
413         attributes->core.id = 0;
414 #endif
415     }
416 }
417 
psa_get_key_lifetime(const psa_key_attributes_t * attributes)418 static inline psa_key_lifetime_t psa_get_key_lifetime(
419     const psa_key_attributes_t *attributes)
420 {
421     return( attributes->core.lifetime );
422 }
423 
psa_set_key_usage_flags(psa_key_attributes_t * attributes,psa_key_usage_t usage_flags)424 static inline void psa_set_key_usage_flags(psa_key_attributes_t *attributes,
425                                            psa_key_usage_t usage_flags)
426 {
427     attributes->core.policy.usage = usage_flags;
428 }
429 
psa_get_key_usage_flags(const psa_key_attributes_t * attributes)430 static inline psa_key_usage_t psa_get_key_usage_flags(
431     const psa_key_attributes_t *attributes)
432 {
433     return( attributes->core.policy.usage );
434 }
435 
psa_set_key_algorithm(psa_key_attributes_t * attributes,psa_algorithm_t alg)436 static inline void psa_set_key_algorithm(psa_key_attributes_t *attributes,
437                                          psa_algorithm_t alg)
438 {
439     attributes->core.policy.alg = alg;
440 }
441 
psa_get_key_algorithm(const psa_key_attributes_t * attributes)442 static inline psa_algorithm_t psa_get_key_algorithm(
443     const psa_key_attributes_t *attributes)
444 {
445     return( attributes->core.policy.alg );
446 }
447 
448 /* This function is declared in crypto_extra.h, which comes after this
449  * header file, but we need the function here, so repeat the declaration. */
450 psa_status_t psa_set_key_domain_parameters(psa_key_attributes_t *attributes,
451                                            psa_key_type_t type,
452                                            const uint8_t *data,
453                                            size_t data_length);
454 
psa_set_key_type(psa_key_attributes_t * attributes,psa_key_type_t type)455 static inline void psa_set_key_type(psa_key_attributes_t *attributes,
456                                     psa_key_type_t type)
457 {
458     if( attributes->domain_parameters == NULL )
459     {
460         /* Common case: quick path */
461         attributes->core.type = type;
462     }
463     else
464     {
465         /* Call the bigger function to free the old domain paramteres.
466          * Ignore any errors which may arise due to type requiring
467          * non-default domain parameters, since this function can't
468          * report errors. */
469         (void) psa_set_key_domain_parameters( attributes, type, NULL, 0 );
470     }
471 }
472 
psa_get_key_type(const psa_key_attributes_t * attributes)473 static inline psa_key_type_t psa_get_key_type(
474     const psa_key_attributes_t *attributes)
475 {
476     return( attributes->core.type );
477 }
478 
psa_set_key_bits(psa_key_attributes_t * attributes,size_t bits)479 static inline void psa_set_key_bits(psa_key_attributes_t *attributes,
480                                     size_t bits)
481 {
482     if( bits > PSA_MAX_KEY_BITS )
483         attributes->core.bits = PSA_KEY_BITS_TOO_LARGE;
484     else
485         attributes->core.bits = (psa_key_bits_t) bits;
486 }
487 
psa_get_key_bits(const psa_key_attributes_t * attributes)488 static inline size_t psa_get_key_bits(
489     const psa_key_attributes_t *attributes)
490 {
491     return( attributes->core.bits );
492 }
493 
494 #ifdef __cplusplus
495 }
496 #endif
497 
498 #endif /* PSA_CRYPTO_STRUCT_H */
499