1 /**
2 * \file alignment.h
3 *
4 * \brief Utility code for dealing with unaligned memory accesses
5 */
6 /*
7 * Copyright The Mbed TLS Contributors
8 * SPDX-License-Identifier: Apache-2.0
9 *
10 * Licensed under the Apache License, Version 2.0 (the "License"); you may
11 * not use this file except in compliance with the License.
12 * You may obtain a copy of the License at
13 *
14 * http://www.apache.org/licenses/LICENSE-2.0
15 *
16 * Unless required by applicable law or agreed to in writing, software
17 * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
18 * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
19 * See the License for the specific language governing permissions and
20 * limitations under the License.
21 */
22
23 #ifndef MBEDTLS_LIBRARY_ALIGNMENT_H
24 #define MBEDTLS_LIBRARY_ALIGNMENT_H
25
26 #include <stdint.h>
27 #include <string.h>
28 #include <stdlib.h>
29
30 #include "mbedtls/build_info.h"
31
32 /*
33 * Define MBEDTLS_EFFICIENT_UNALIGNED_ACCESS for architectures where unaligned memory
34 * accesses are known to be efficient.
35 *
36 * All functions defined here will behave correctly regardless, but might be less
37 * efficient when this is not defined.
38 */
39 #if defined(__ARM_FEATURE_UNALIGNED) \
40 || defined(__i386__) || defined(__amd64__) || defined(__x86_64__)
41 /*
42 * __ARM_FEATURE_UNALIGNED is defined where appropriate by armcc, gcc 7, clang 9
43 * (and later versions) for Arm v7 and later; all x86 platforms should have
44 * efficient unaligned access.
45 */
46 #define MBEDTLS_EFFICIENT_UNALIGNED_ACCESS
47 #endif
48
49 /**
50 * Read the unsigned 16 bits integer from the given address, which need not
51 * be aligned.
52 *
53 * \param p pointer to 2 bytes of data
54 * \return Data at the given address
55 */
mbedtls_get_unaligned_uint16(const void * p)56 inline uint16_t mbedtls_get_unaligned_uint16(const void *p)
57 {
58 uint16_t r;
59 memcpy(&r, p, sizeof(r));
60 return r;
61 }
62
63 /**
64 * Write the unsigned 16 bits integer to the given address, which need not
65 * be aligned.
66 *
67 * \param p pointer to 2 bytes of data
68 * \param x data to write
69 */
mbedtls_put_unaligned_uint16(void * p,uint16_t x)70 inline void mbedtls_put_unaligned_uint16(void *p, uint16_t x)
71 {
72 memcpy(p, &x, sizeof(x));
73 }
74
75 /**
76 * Read the unsigned 32 bits integer from the given address, which need not
77 * be aligned.
78 *
79 * \param p pointer to 4 bytes of data
80 * \return Data at the given address
81 */
mbedtls_get_unaligned_uint32(const void * p)82 inline uint32_t mbedtls_get_unaligned_uint32(const void *p)
83 {
84 uint32_t r;
85 memcpy(&r, p, sizeof(r));
86 return r;
87 }
88
89 /**
90 * Write the unsigned 32 bits integer to the given address, which need not
91 * be aligned.
92 *
93 * \param p pointer to 4 bytes of data
94 * \param x data to write
95 */
mbedtls_put_unaligned_uint32(void * p,uint32_t x)96 inline void mbedtls_put_unaligned_uint32(void *p, uint32_t x)
97 {
98 memcpy(p, &x, sizeof(x));
99 }
100
101 /**
102 * Read the unsigned 64 bits integer from the given address, which need not
103 * be aligned.
104 *
105 * \param p pointer to 8 bytes of data
106 * \return Data at the given address
107 */
mbedtls_get_unaligned_uint64(const void * p)108 inline uint64_t mbedtls_get_unaligned_uint64(const void *p)
109 {
110 uint64_t r;
111 memcpy(&r, p, sizeof(r));
112 return r;
113 }
114
115 /**
116 * Write the unsigned 64 bits integer to the given address, which need not
117 * be aligned.
118 *
119 * \param p pointer to 8 bytes of data
120 * \param x data to write
121 */
mbedtls_put_unaligned_uint64(void * p,uint64_t x)122 inline void mbedtls_put_unaligned_uint64(void *p, uint64_t x)
123 {
124 memcpy(p, &x, sizeof(x));
125 }
126
127 /** Byte Reading Macros
128 *
129 * Given a multi-byte integer \p x, MBEDTLS_BYTE_n retrieves the n-th
130 * byte from x, where byte 0 is the least significant byte.
131 */
132 #define MBEDTLS_BYTE_0(x) ((uint8_t) ((x) & 0xff))
133 #define MBEDTLS_BYTE_1(x) ((uint8_t) (((x) >> 8) & 0xff))
134 #define MBEDTLS_BYTE_2(x) ((uint8_t) (((x) >> 16) & 0xff))
135 #define MBEDTLS_BYTE_3(x) ((uint8_t) (((x) >> 24) & 0xff))
136 #define MBEDTLS_BYTE_4(x) ((uint8_t) (((x) >> 32) & 0xff))
137 #define MBEDTLS_BYTE_5(x) ((uint8_t) (((x) >> 40) & 0xff))
138 #define MBEDTLS_BYTE_6(x) ((uint8_t) (((x) >> 48) & 0xff))
139 #define MBEDTLS_BYTE_7(x) ((uint8_t) (((x) >> 56) & 0xff))
140
141 /*
142 * Detect GCC built-in byteswap routines
143 */
144 #if defined(__GNUC__) && defined(__GNUC_PREREQ)
145 #if __GNUC_PREREQ(4, 8)
146 #define MBEDTLS_BSWAP16 __builtin_bswap16
147 #endif /* __GNUC_PREREQ(4,8) */
148 #if __GNUC_PREREQ(4, 3)
149 #define MBEDTLS_BSWAP32 __builtin_bswap32
150 #define MBEDTLS_BSWAP64 __builtin_bswap64
151 #endif /* __GNUC_PREREQ(4,3) */
152 #endif /* defined(__GNUC__) && defined(__GNUC_PREREQ) */
153
154 /*
155 * Detect Clang built-in byteswap routines
156 */
157 #if defined(__clang__) && defined(__has_builtin)
158 #if __has_builtin(__builtin_bswap16) && !defined(MBEDTLS_BSWAP16)
159 #define MBEDTLS_BSWAP16 __builtin_bswap16
160 #endif /* __has_builtin(__builtin_bswap16) */
161 #if __has_builtin(__builtin_bswap32) && !defined(MBEDTLS_BSWAP32)
162 #define MBEDTLS_BSWAP32 __builtin_bswap32
163 #endif /* __has_builtin(__builtin_bswap32) */
164 #if __has_builtin(__builtin_bswap64) && !defined(MBEDTLS_BSWAP64)
165 #define MBEDTLS_BSWAP64 __builtin_bswap64
166 #endif /* __has_builtin(__builtin_bswap64) */
167 #endif /* defined(__clang__) && defined(__has_builtin) */
168
169 /*
170 * Detect MSVC built-in byteswap routines
171 */
172 #if defined(_MSC_VER)
173 #if !defined(MBEDTLS_BSWAP16)
174 #define MBEDTLS_BSWAP16 _byteswap_ushort
175 #endif
176 #if !defined(MBEDTLS_BSWAP32)
177 #define MBEDTLS_BSWAP32 _byteswap_ulong
178 #endif
179 #if !defined(MBEDTLS_BSWAP64)
180 #define MBEDTLS_BSWAP64 _byteswap_uint64
181 #endif
182 #endif /* defined(_MSC_VER) */
183
184 /* Detect armcc built-in byteswap routine */
185 #if defined(__ARMCC_VERSION) && (__ARMCC_VERSION >= 410000) && !defined(MBEDTLS_BSWAP32)
186 #define MBEDTLS_BSWAP32 __rev
187 #endif
188
189 /*
190 * Where compiler built-ins are not present, fall back to C code that the
191 * compiler may be able to detect and transform into the relevant bswap or
192 * similar instruction.
193 */
194 #if !defined(MBEDTLS_BSWAP16)
mbedtls_bswap16(uint16_t x)195 static inline uint16_t mbedtls_bswap16(uint16_t x)
196 {
197 return
198 (x & 0x00ff) << 8 |
199 (x & 0xff00) >> 8;
200 }
201 #define MBEDTLS_BSWAP16 mbedtls_bswap16
202 #endif /* !defined(MBEDTLS_BSWAP16) */
203
204 #if !defined(MBEDTLS_BSWAP32)
mbedtls_bswap32(uint32_t x)205 static inline uint32_t mbedtls_bswap32(uint32_t x)
206 {
207 return
208 (x & 0x000000ff) << 24 |
209 (x & 0x0000ff00) << 8 |
210 (x & 0x00ff0000) >> 8 |
211 (x & 0xff000000) >> 24;
212 }
213 #define MBEDTLS_BSWAP32 mbedtls_bswap32
214 #endif /* !defined(MBEDTLS_BSWAP32) */
215
216 #if !defined(MBEDTLS_BSWAP64)
mbedtls_bswap64(uint64_t x)217 static inline uint64_t mbedtls_bswap64(uint64_t x)
218 {
219 return
220 (x & 0x00000000000000ffULL) << 56 |
221 (x & 0x000000000000ff00ULL) << 40 |
222 (x & 0x0000000000ff0000ULL) << 24 |
223 (x & 0x00000000ff000000ULL) << 8 |
224 (x & 0x000000ff00000000ULL) >> 8 |
225 (x & 0x0000ff0000000000ULL) >> 24 |
226 (x & 0x00ff000000000000ULL) >> 40 |
227 (x & 0xff00000000000000ULL) >> 56;
228 }
229 #define MBEDTLS_BSWAP64 mbedtls_bswap64
230 #endif /* !defined(MBEDTLS_BSWAP64) */
231
232 #if !defined(__BYTE_ORDER__)
233 static const uint16_t mbedtls_byte_order_detector = { 0x100 };
234 #define MBEDTLS_IS_BIG_ENDIAN (*((unsigned char *) (&mbedtls_byte_order_detector)) == 0x01)
235 #else
236 #define MBEDTLS_IS_BIG_ENDIAN ((__BYTE_ORDER__) == (__ORDER_BIG_ENDIAN__))
237 #endif /* !defined(__BYTE_ORDER__) */
238
239 /**
240 * Get the unsigned 32 bits integer corresponding to four bytes in
241 * big-endian order (MSB first).
242 *
243 * \param data Base address of the memory to get the four bytes from.
244 * \param offset Offset from \p data of the first and most significant
245 * byte of the four bytes to build the 32 bits unsigned
246 * integer from.
247 */
248 #define MBEDTLS_GET_UINT32_BE(data, offset) \
249 ((MBEDTLS_IS_BIG_ENDIAN) \
250 ? mbedtls_get_unaligned_uint32((data) + (offset)) \
251 : MBEDTLS_BSWAP32(mbedtls_get_unaligned_uint32((data) + (offset))) \
252 )
253
254 /**
255 * Put in memory a 32 bits unsigned integer in big-endian order.
256 *
257 * \param n 32 bits unsigned integer to put in memory.
258 * \param data Base address of the memory where to put the 32
259 * bits unsigned integer in.
260 * \param offset Offset from \p data where to put the most significant
261 * byte of the 32 bits unsigned integer \p n.
262 */
263 #define MBEDTLS_PUT_UINT32_BE(n, data, offset) \
264 { \
265 if (MBEDTLS_IS_BIG_ENDIAN) \
266 { \
267 mbedtls_put_unaligned_uint32((data) + (offset), (uint32_t) (n)); \
268 } \
269 else \
270 { \
271 mbedtls_put_unaligned_uint32((data) + (offset), MBEDTLS_BSWAP32((uint32_t) (n))); \
272 } \
273 }
274
275 /**
276 * Get the unsigned 32 bits integer corresponding to four bytes in
277 * little-endian order (LSB first).
278 *
279 * \param data Base address of the memory to get the four bytes from.
280 * \param offset Offset from \p data of the first and least significant
281 * byte of the four bytes to build the 32 bits unsigned
282 * integer from.
283 */
284 #define MBEDTLS_GET_UINT32_LE(data, offset) \
285 ((MBEDTLS_IS_BIG_ENDIAN) \
286 ? MBEDTLS_BSWAP32(mbedtls_get_unaligned_uint32((data) + (offset))) \
287 : mbedtls_get_unaligned_uint32((data) + (offset)) \
288 )
289
290
291 /**
292 * Put in memory a 32 bits unsigned integer in little-endian order.
293 *
294 * \param n 32 bits unsigned integer to put in memory.
295 * \param data Base address of the memory where to put the 32
296 * bits unsigned integer in.
297 * \param offset Offset from \p data where to put the least significant
298 * byte of the 32 bits unsigned integer \p n.
299 */
300 #define MBEDTLS_PUT_UINT32_LE(n, data, offset) \
301 { \
302 if (MBEDTLS_IS_BIG_ENDIAN) \
303 { \
304 mbedtls_put_unaligned_uint32((data) + (offset), MBEDTLS_BSWAP32((uint32_t) (n))); \
305 } \
306 else \
307 { \
308 mbedtls_put_unaligned_uint32((data) + (offset), ((uint32_t) (n))); \
309 } \
310 }
311
312 /**
313 * Get the unsigned 16 bits integer corresponding to two bytes in
314 * little-endian order (LSB first).
315 *
316 * \param data Base address of the memory to get the two bytes from.
317 * \param offset Offset from \p data of the first and least significant
318 * byte of the two bytes to build the 16 bits unsigned
319 * integer from.
320 */
321 #define MBEDTLS_GET_UINT16_LE(data, offset) \
322 ((MBEDTLS_IS_BIG_ENDIAN) \
323 ? MBEDTLS_BSWAP16(mbedtls_get_unaligned_uint16((data) + (offset))) \
324 : mbedtls_get_unaligned_uint16((data) + (offset)) \
325 )
326
327 /**
328 * Put in memory a 16 bits unsigned integer in little-endian order.
329 *
330 * \param n 16 bits unsigned integer to put in memory.
331 * \param data Base address of the memory where to put the 16
332 * bits unsigned integer in.
333 * \param offset Offset from \p data where to put the least significant
334 * byte of the 16 bits unsigned integer \p n.
335 */
336 #define MBEDTLS_PUT_UINT16_LE(n, data, offset) \
337 { \
338 if (MBEDTLS_IS_BIG_ENDIAN) \
339 { \
340 mbedtls_put_unaligned_uint16((data) + (offset), MBEDTLS_BSWAP16((uint16_t) (n))); \
341 } \
342 else \
343 { \
344 mbedtls_put_unaligned_uint16((data) + (offset), (uint16_t) (n)); \
345 } \
346 }
347
348 /**
349 * Get the unsigned 16 bits integer corresponding to two bytes in
350 * big-endian order (MSB first).
351 *
352 * \param data Base address of the memory to get the two bytes from.
353 * \param offset Offset from \p data of the first and most significant
354 * byte of the two bytes to build the 16 bits unsigned
355 * integer from.
356 */
357 #define MBEDTLS_GET_UINT16_BE(data, offset) \
358 ((MBEDTLS_IS_BIG_ENDIAN) \
359 ? mbedtls_get_unaligned_uint16((data) + (offset)) \
360 : MBEDTLS_BSWAP16(mbedtls_get_unaligned_uint16((data) + (offset))) \
361 )
362
363 /**
364 * Put in memory a 16 bits unsigned integer in big-endian order.
365 *
366 * \param n 16 bits unsigned integer to put in memory.
367 * \param data Base address of the memory where to put the 16
368 * bits unsigned integer in.
369 * \param offset Offset from \p data where to put the most significant
370 * byte of the 16 bits unsigned integer \p n.
371 */
372 #define MBEDTLS_PUT_UINT16_BE(n, data, offset) \
373 { \
374 if (MBEDTLS_IS_BIG_ENDIAN) \
375 { \
376 mbedtls_put_unaligned_uint16((data) + (offset), (uint16_t) (n)); \
377 } \
378 else \
379 { \
380 mbedtls_put_unaligned_uint16((data) + (offset), MBEDTLS_BSWAP16((uint16_t) (n))); \
381 } \
382 }
383
384 /**
385 * Get the unsigned 24 bits integer corresponding to three bytes in
386 * big-endian order (MSB first).
387 *
388 * \param data Base address of the memory to get the three bytes from.
389 * \param offset Offset from \p data of the first and most significant
390 * byte of the three bytes to build the 24 bits unsigned
391 * integer from.
392 */
393 #define MBEDTLS_GET_UINT24_BE(data, offset) \
394 ( \
395 ((uint32_t) (data)[(offset)] << 16) \
396 | ((uint32_t) (data)[(offset) + 1] << 8) \
397 | ((uint32_t) (data)[(offset) + 2]) \
398 )
399
400 /**
401 * Put in memory a 24 bits unsigned integer in big-endian order.
402 *
403 * \param n 24 bits unsigned integer to put in memory.
404 * \param data Base address of the memory where to put the 24
405 * bits unsigned integer in.
406 * \param offset Offset from \p data where to put the most significant
407 * byte of the 24 bits unsigned integer \p n.
408 */
409 #define MBEDTLS_PUT_UINT24_BE(n, data, offset) \
410 { \
411 (data)[(offset)] = MBEDTLS_BYTE_2(n); \
412 (data)[(offset) + 1] = MBEDTLS_BYTE_1(n); \
413 (data)[(offset) + 2] = MBEDTLS_BYTE_0(n); \
414 }
415
416 /**
417 * Get the unsigned 24 bits integer corresponding to three bytes in
418 * little-endian order (LSB first).
419 *
420 * \param data Base address of the memory to get the three bytes from.
421 * \param offset Offset from \p data of the first and least significant
422 * byte of the three bytes to build the 24 bits unsigned
423 * integer from.
424 */
425 #define MBEDTLS_GET_UINT24_LE(data, offset) \
426 ( \
427 ((uint32_t) (data)[(offset)]) \
428 | ((uint32_t) (data)[(offset) + 1] << 8) \
429 | ((uint32_t) (data)[(offset) + 2] << 16) \
430 )
431
432 /**
433 * Put in memory a 24 bits unsigned integer in little-endian order.
434 *
435 * \param n 24 bits unsigned integer to put in memory.
436 * \param data Base address of the memory where to put the 24
437 * bits unsigned integer in.
438 * \param offset Offset from \p data where to put the least significant
439 * byte of the 24 bits unsigned integer \p n.
440 */
441 #define MBEDTLS_PUT_UINT24_LE(n, data, offset) \
442 { \
443 (data)[(offset)] = MBEDTLS_BYTE_0(n); \
444 (data)[(offset) + 1] = MBEDTLS_BYTE_1(n); \
445 (data)[(offset) + 2] = MBEDTLS_BYTE_2(n); \
446 }
447
448 /**
449 * Get the unsigned 64 bits integer corresponding to eight bytes in
450 * big-endian order (MSB first).
451 *
452 * \param data Base address of the memory to get the eight bytes from.
453 * \param offset Offset from \p data of the first and most significant
454 * byte of the eight bytes to build the 64 bits unsigned
455 * integer from.
456 */
457 #define MBEDTLS_GET_UINT64_BE(data, offset) \
458 ((MBEDTLS_IS_BIG_ENDIAN) \
459 ? mbedtls_get_unaligned_uint64((data) + (offset)) \
460 : MBEDTLS_BSWAP64(mbedtls_get_unaligned_uint64((data) + (offset))) \
461 )
462
463 /**
464 * Put in memory a 64 bits unsigned integer in big-endian order.
465 *
466 * \param n 64 bits unsigned integer to put in memory.
467 * \param data Base address of the memory where to put the 64
468 * bits unsigned integer in.
469 * \param offset Offset from \p data where to put the most significant
470 * byte of the 64 bits unsigned integer \p n.
471 */
472 #define MBEDTLS_PUT_UINT64_BE(n, data, offset) \
473 { \
474 if (MBEDTLS_IS_BIG_ENDIAN) \
475 { \
476 mbedtls_put_unaligned_uint64((data) + (offset), (uint64_t) (n)); \
477 } \
478 else \
479 { \
480 mbedtls_put_unaligned_uint64((data) + (offset), MBEDTLS_BSWAP64((uint64_t) (n))); \
481 } \
482 }
483
484 /**
485 * Get the unsigned 64 bits integer corresponding to eight bytes in
486 * little-endian order (LSB first).
487 *
488 * \param data Base address of the memory to get the eight bytes from.
489 * \param offset Offset from \p data of the first and least significant
490 * byte of the eight bytes to build the 64 bits unsigned
491 * integer from.
492 */
493 #define MBEDTLS_GET_UINT64_LE(data, offset) \
494 ((MBEDTLS_IS_BIG_ENDIAN) \
495 ? MBEDTLS_BSWAP64(mbedtls_get_unaligned_uint64((data) + (offset))) \
496 : mbedtls_get_unaligned_uint64((data) + (offset)) \
497 )
498
499 /**
500 * Put in memory a 64 bits unsigned integer in little-endian order.
501 *
502 * \param n 64 bits unsigned integer to put in memory.
503 * \param data Base address of the memory where to put the 64
504 * bits unsigned integer in.
505 * \param offset Offset from \p data where to put the least significant
506 * byte of the 64 bits unsigned integer \p n.
507 */
508 #define MBEDTLS_PUT_UINT64_LE(n, data, offset) \
509 { \
510 if (MBEDTLS_IS_BIG_ENDIAN) \
511 { \
512 mbedtls_put_unaligned_uint64((data) + (offset), MBEDTLS_BSWAP64((uint64_t) (n))); \
513 } \
514 else \
515 { \
516 mbedtls_put_unaligned_uint64((data) + (offset), (uint64_t) (n)); \
517 } \
518 }
519
520 #endif /* MBEDTLS_LIBRARY_ALIGNMENT_H */
521
