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 */ 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 */ 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 */ 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 */ 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 */ 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 */ 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) 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) 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) 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