sjana | 76e88d2 | 2020-03-19 13:24:39 -0400 | [diff] [blame^] | 1 | /* |
| 2 | * Copyright (c) 2005-2017 Lev Walkin <vlm@lionet.info>. All rights reserved. |
| 3 | * Redistribution and modifications are permitted subject to BSD license. |
| 4 | */ |
| 5 | #include <asn_system.h> |
| 6 | #include <asn_internal.h> |
| 7 | #include <per_support.h> |
| 8 | |
| 9 | /* |
| 10 | * X.691-201508 #10.9 General rules for encoding a length determinant. |
| 11 | * Get the optionally constrained length "n" from the stream. |
| 12 | */ |
| 13 | ssize_t |
| 14 | uper_get_length(asn_per_data_t *pd, int ebits, size_t lower_bound, |
| 15 | int *repeat) { |
| 16 | ssize_t value; |
| 17 | |
| 18 | *repeat = 0; |
| 19 | |
| 20 | /* #11.9.4.1 Encoding if constrained (according to effective bits) */ |
| 21 | if(ebits >= 0 && ebits <= 16) { |
| 22 | value = per_get_few_bits(pd, ebits); |
| 23 | if(value >= 0) value += lower_bound; |
| 24 | return value; |
| 25 | } |
| 26 | |
| 27 | value = per_get_few_bits(pd, 8); |
| 28 | if((value & 0x80) == 0) { /* #11.9.3.6 */ |
| 29 | return (value & 0x7F); |
| 30 | } else if((value & 0x40) == 0) { /* #11.9.3.7 */ |
| 31 | /* bit 8 ... set to 1 and bit 7 ... set to zero */ |
| 32 | value = ((value & 0x3f) << 8) | per_get_few_bits(pd, 8); |
| 33 | return value; /* potential -1 from per_get_few_bits passes through. */ |
| 34 | } else if(value < 0) { |
| 35 | ASN_DEBUG("END of stream reached for PER"); |
| 36 | return -1; |
| 37 | } |
| 38 | value &= 0x3f; /* this is "m" from X.691, #11.9.3.8 */ |
| 39 | if(value < 1 || value > 4) { |
| 40 | return -1; /* Prohibited by #11.9.3.8 */ |
| 41 | } |
| 42 | *repeat = 1; |
| 43 | return (16384 * value); |
| 44 | } |
| 45 | |
| 46 | /* |
| 47 | * Get the normally small length "n". |
| 48 | * This procedure used to decode length of extensions bit-maps |
| 49 | * for SET and SEQUENCE types. |
| 50 | */ |
| 51 | ssize_t |
| 52 | uper_get_nslength(asn_per_data_t *pd) { |
| 53 | ssize_t length; |
| 54 | |
| 55 | ASN_DEBUG("Getting normally small length"); |
| 56 | |
| 57 | if(per_get_few_bits(pd, 1) == 0) { |
| 58 | length = per_get_few_bits(pd, 6) + 1; |
| 59 | if(length <= 0) return -1; |
| 60 | ASN_DEBUG("l=%d", (int)length); |
| 61 | return length; |
| 62 | } else { |
| 63 | int repeat; |
| 64 | length = uper_get_length(pd, -1, 0, &repeat); |
| 65 | if(length >= 0 && !repeat) return length; |
| 66 | return -1; /* Error, or do not support >16K extensions */ |
| 67 | } |
| 68 | } |
| 69 | |
| 70 | /* |
| 71 | * Get the normally small non-negative whole number. |
| 72 | * X.691, #10.6 |
| 73 | */ |
| 74 | ssize_t |
| 75 | uper_get_nsnnwn(asn_per_data_t *pd) { |
| 76 | ssize_t value; |
| 77 | |
| 78 | value = per_get_few_bits(pd, 7); |
| 79 | if(value & 64) { /* implicit (value < 0) */ |
| 80 | value &= 63; |
| 81 | value <<= 2; |
| 82 | value |= per_get_few_bits(pd, 2); |
| 83 | if(value & 128) /* implicit (value < 0) */ |
| 84 | return -1; |
| 85 | if(value == 0) |
| 86 | return 0; |
| 87 | if(value >= 3) |
| 88 | return -1; |
| 89 | value = per_get_few_bits(pd, 8 * value); |
| 90 | return value; |
| 91 | } |
| 92 | |
| 93 | return value; |
| 94 | } |
| 95 | |
| 96 | /* |
| 97 | * X.691-11/2008, #11.6 |
| 98 | * Encoding of a normally small non-negative whole number |
| 99 | */ |
| 100 | int |
| 101 | uper_put_nsnnwn(asn_per_outp_t *po, int n) { |
| 102 | int bytes; |
| 103 | |
| 104 | if(n <= 63) { |
| 105 | if(n < 0) return -1; |
| 106 | return per_put_few_bits(po, n, 7); |
| 107 | } |
| 108 | if(n < 256) |
| 109 | bytes = 1; |
| 110 | else if(n < 65536) |
| 111 | bytes = 2; |
| 112 | else if(n < 256 * 65536) |
| 113 | bytes = 3; |
| 114 | else |
| 115 | return -1; /* This is not a "normally small" value */ |
| 116 | if(per_put_few_bits(po, bytes, 8)) |
| 117 | return -1; |
| 118 | |
| 119 | return per_put_few_bits(po, n, 8 * bytes); |
| 120 | } |
| 121 | |
| 122 | |
| 123 | /* X.691-2008/11, #11.5.6 -> #11.3 */ |
| 124 | int uper_get_constrained_whole_number(asn_per_data_t *pd, unsigned long *out_value, int nbits) { |
| 125 | unsigned long lhalf; /* Lower half of the number*/ |
| 126 | long half; |
| 127 | |
| 128 | if(nbits <= 31) { |
| 129 | half = per_get_few_bits(pd, nbits); |
| 130 | if(half < 0) return -1; |
| 131 | *out_value = half; |
| 132 | return 0; |
| 133 | } |
| 134 | |
| 135 | if((size_t)nbits > 8 * sizeof(*out_value)) |
| 136 | return -1; /* RANGE */ |
| 137 | |
| 138 | half = per_get_few_bits(pd, 31); |
| 139 | if(half < 0) return -1; |
| 140 | |
| 141 | if(uper_get_constrained_whole_number(pd, &lhalf, nbits - 31)) |
| 142 | return -1; |
| 143 | |
| 144 | *out_value = ((unsigned long)half << (nbits - 31)) | lhalf; |
| 145 | return 0; |
| 146 | } |
| 147 | |
| 148 | |
| 149 | /* X.691-2008/11, #11.5.6 -> #11.3 */ |
| 150 | int |
| 151 | uper_put_constrained_whole_number_u(asn_per_outp_t *po, unsigned long v, |
| 152 | int nbits) { |
| 153 | if(nbits <= 31) { |
| 154 | return per_put_few_bits(po, v, nbits); |
| 155 | } else { |
| 156 | /* Put higher portion first, followed by lower 31-bit */ |
| 157 | if(uper_put_constrained_whole_number_u(po, v >> 31, nbits - 31)) |
| 158 | return -1; |
| 159 | return per_put_few_bits(po, v, 31); |
| 160 | } |
| 161 | } |
| 162 | |
| 163 | /* |
| 164 | * X.691 (08/2015) #11.9 "General rules for encoding a length determinant" |
| 165 | * Put the length "n" (or part of it) into the stream. |
| 166 | */ |
| 167 | ssize_t |
| 168 | uper_put_length(asn_per_outp_t *po, size_t length, int *need_eom) { |
| 169 | int dummy = 0; |
| 170 | if(!need_eom) need_eom = &dummy; |
| 171 | |
| 172 | if(length <= 127) { /* #11.9.3.6 */ |
| 173 | *need_eom = 0; |
| 174 | return per_put_few_bits(po, length, 8) |
| 175 | ? -1 : (ssize_t)length; |
| 176 | } else if(length < 16384) { /* #10.9.3.7 */ |
| 177 | *need_eom = 0; |
| 178 | return per_put_few_bits(po, length|0x8000, 16) |
| 179 | ? -1 : (ssize_t)length; |
| 180 | } |
| 181 | |
| 182 | *need_eom = 0 == (length & 16383); |
| 183 | length >>= 14; |
| 184 | if(length > 4) { |
| 185 | *need_eom = 0; |
| 186 | length = 4; |
| 187 | } |
| 188 | |
| 189 | return per_put_few_bits(po, 0xC0 | length, 8) |
| 190 | ? -1 : (ssize_t)(length << 14); |
| 191 | |
| 192 | } |
| 193 | |
| 194 | |
| 195 | /* |
| 196 | * Put the normally small length "n" into the stream. |
| 197 | * This procedure used to encode length of extensions bit-maps |
| 198 | * for SET and SEQUENCE types. |
| 199 | */ |
| 200 | int |
| 201 | uper_put_nslength(asn_per_outp_t *po, size_t length) { |
| 202 | if(length <= 64) { |
| 203 | /* #11.9.3.4 */ |
| 204 | if(length == 0) return -1; |
| 205 | return per_put_few_bits(po, length - 1, 7) ? -1 : 0; |
| 206 | } else { |
| 207 | int need_eom = 0; |
| 208 | if(uper_put_length(po, length, &need_eom) != (ssize_t)length |
| 209 | || need_eom) { |
| 210 | /* This might happen in case of >16K extensions */ |
| 211 | return -1; |
| 212 | } |
| 213 | } |
| 214 | |
| 215 | return 0; |
| 216 | } |
| 217 | |
| 218 | static int |
| 219 | per__long_range(long lb, long ub, unsigned long *range_r) { |
| 220 | unsigned long bounds_range; |
| 221 | if((ub < 0) == (lb < 0)) { |
| 222 | bounds_range = ub - lb; |
| 223 | } else if(lb < 0) { |
| 224 | assert(ub >= 0); |
| 225 | bounds_range = 1 + ((unsigned long)ub + (unsigned long)-(lb + 1)); |
| 226 | } else { |
| 227 | assert(!"Unreachable"); |
| 228 | return -1; |
| 229 | } |
| 230 | *range_r = bounds_range; |
| 231 | return 0; |
| 232 | } |
| 233 | |
| 234 | int |
| 235 | per_long_range_rebase(long v, long lb, long ub, unsigned long *output) { |
| 236 | unsigned long range; |
| 237 | |
| 238 | assert(lb <= ub); |
| 239 | |
| 240 | if(v < lb || v > ub || per__long_range(lb, ub, &range) < 0) { |
| 241 | /* Range error. */ |
| 242 | return -1; |
| 243 | } |
| 244 | |
| 245 | /* |
| 246 | * Fundamentally what we're doing is returning (v-lb). |
| 247 | * However, this triggers undefined behavior when the word width |
| 248 | * of signed (v) is the same as the size of unsigned (*output). |
| 249 | * In practice, it triggers the UndefinedSanitizer. Therefore we shall |
| 250 | * compute the ranges accurately to avoid C's undefined behavior. |
| 251 | */ |
| 252 | if((v < 0) == (lb < 0)) { |
| 253 | *output = v-lb; |
| 254 | return 0; |
| 255 | } else if(v < 0) { |
| 256 | unsigned long rebased = 1 + (unsigned long)-(v+1) + (unsigned long)lb; |
| 257 | assert(rebased <= range); /* By construction */ |
| 258 | *output = rebased; |
| 259 | return 0; |
| 260 | } else if(lb < 0) { |
| 261 | unsigned long rebased = 1 + (unsigned long)-(lb+1) + (unsigned long)v; |
| 262 | assert(rebased <= range); /* By construction */ |
| 263 | *output = rebased; |
| 264 | return 0; |
| 265 | } else { |
| 266 | assert(!"Unreachable"); |
| 267 | return -1; |
| 268 | } |
| 269 | } |
| 270 | |
| 271 | int |
| 272 | per_long_range_unrebase(unsigned long inp, long lb, long ub, long *outp) { |
| 273 | unsigned long range; |
| 274 | |
| 275 | if(per__long_range(lb, ub, &range) != 0) { |
| 276 | return -1; |
| 277 | } |
| 278 | |
| 279 | if(inp > range) { |
| 280 | /* |
| 281 | * We can encode something in the given number of bits that technically |
| 282 | * exceeds the range. This is an avenue for security errors, |
| 283 | * so we don't allow that. |
| 284 | */ |
| 285 | return -1; |
| 286 | } |
| 287 | |
| 288 | if(inp <= LONG_MAX) { |
| 289 | *outp = (long)inp + lb; |
| 290 | } else { |
| 291 | *outp = (lb + LONG_MAX + 1) + (long)((inp - LONG_MAX) - 1); |
| 292 | } |
| 293 | |
| 294 | return 0; |
| 295 | } |
| 296 | |
| 297 | int32_t |
| 298 | aper_get_align(asn_per_data_t *pd) { |
| 299 | |
| 300 | if(pd->nboff & 0x7) { |
| 301 | ASN_DEBUG("Aligning %ld bits", 8 - ((unsigned long)pd->nboff & 0x7)); |
| 302 | return per_get_few_bits(pd, 8 - (pd->nboff & 0x7)); |
| 303 | } |
| 304 | return 0; |
| 305 | } |
| 306 | |
| 307 | ssize_t |
| 308 | aper_get_length(asn_per_data_t *pd, int range, int ebits, int *repeat) { |
| 309 | ssize_t value; |
| 310 | |
| 311 | *repeat = 0; |
| 312 | |
| 313 | if (range <= 65536 && range >= 0) |
| 314 | return aper_get_nsnnwn(pd, range); |
| 315 | |
| 316 | if (aper_get_align(pd) < 0) |
| 317 | return -1; |
| 318 | |
| 319 | if(ebits >= 0) return per_get_few_bits(pd, ebits); |
| 320 | |
| 321 | value = per_get_few_bits(pd, 8); |
| 322 | if(value < 0) return -1; |
| 323 | if((value & 128) == 0) /* #10.9.3.6 */ |
| 324 | return (value & 0x7F); |
| 325 | if((value & 64) == 0) { /* #10.9.3.7 */ |
| 326 | value = ((value & 63) << 8) | per_get_few_bits(pd, 8); |
| 327 | if(value < 0) return -1; |
| 328 | return value; |
| 329 | } |
| 330 | value &= 63; /* this is "m" from X.691, #10.9.3.8 */ |
| 331 | if(value < 1 || value > 4) |
| 332 | return -1; |
| 333 | *repeat = 1; |
| 334 | return (16384 * value); |
| 335 | } |
| 336 | |
| 337 | ssize_t |
| 338 | aper_get_nslength(asn_per_data_t *pd) { |
| 339 | ssize_t length; |
| 340 | |
| 341 | ASN_DEBUG("Getting normally small length"); |
| 342 | |
| 343 | if(per_get_few_bits(pd, 1) == 0) { |
| 344 | length = per_get_few_bits(pd, 6) + 1; |
| 345 | if(length <= 0) return -1; |
| 346 | ASN_DEBUG("l=%ld", length); |
| 347 | return length; |
| 348 | } else { |
| 349 | int repeat; |
| 350 | length = aper_get_length(pd, -1, -1, &repeat); |
| 351 | if(length >= 0 && !repeat) return length; |
| 352 | return -1; /* Error, or do not support >16K extensions */ |
| 353 | } |
| 354 | } |
| 355 | |
| 356 | ssize_t |
| 357 | aper_get_nsnnwn(asn_per_data_t *pd, int range) { |
| 358 | ssize_t value; |
| 359 | int bytes = 0; |
| 360 | |
| 361 | ASN_DEBUG("getting nsnnwn with range %d", range); |
| 362 | |
| 363 | if(range <= 255) { |
| 364 | int i; |
| 365 | |
| 366 | if (range < 0) return -1; |
| 367 | /* 1 -> 8 bits */ |
| 368 | for (i = 1; i <= 8; i++) { |
| 369 | int upper = 1 << i; |
| 370 | if (upper >= range) |
| 371 | break; |
| 372 | } |
| 373 | value = per_get_few_bits(pd, i); |
| 374 | return value; |
| 375 | } else if (range == 256){ |
| 376 | /* 1 byte */ |
| 377 | bytes = 1; |
| 378 | } else if (range <= 65536) { |
| 379 | /* 2 bytes */ |
| 380 | bytes = 2; |
| 381 | } else { |
| 382 | return -1; |
| 383 | } |
| 384 | if (aper_get_align(pd) < 0) |
| 385 | return -1; |
| 386 | value = per_get_few_bits(pd, 8 * bytes); |
| 387 | return value; |
| 388 | } |
| 389 | |
| 390 | int aper_put_align(asn_per_outp_t *po) { |
| 391 | |
| 392 | if(po->nboff & 0x7) { |
| 393 | ASN_DEBUG("Aligning %ld bits", 8 - ((unsigned long)po->nboff & 0x7)); |
| 394 | if(per_put_few_bits(po, 0x00, (8 - (po->nboff & 0x7)))) |
| 395 | return -1; |
| 396 | } |
| 397 | return 0; |
| 398 | } |
| 399 | |
| 400 | ssize_t |
| 401 | aper_put_length(asn_per_outp_t *po, int range, size_t length) { |
| 402 | |
| 403 | ASN_DEBUG("APER put length %zu with range %d", length, range); |
| 404 | |
| 405 | /* 10.9 X.691 Note 2 */ |
| 406 | if (range <= 65536 && range >= 0) |
| 407 | return aper_put_nsnnwn(po, range, length); |
| 408 | |
| 409 | if (aper_put_align(po) < 0) |
| 410 | return -1; |
| 411 | |
| 412 | if(length <= 127) /* #10.9.3.6 */{ |
| 413 | return per_put_few_bits(po, length, 8) |
| 414 | ? -1 : (ssize_t)length; |
| 415 | } |
| 416 | else if(length < 16384) /* #10.9.3.7 */ |
| 417 | return per_put_few_bits(po, length|0x8000, 16) |
| 418 | ? -1 : (ssize_t)length; |
| 419 | |
| 420 | length >>= 14; |
| 421 | if(length > 4) length = 4; |
| 422 | |
| 423 | return per_put_few_bits(po, 0xC0 | length, 8) |
| 424 | ? -1 : (ssize_t)(length << 14); |
| 425 | } |
| 426 | |
| 427 | |
| 428 | int |
| 429 | aper_put_nslength(asn_per_outp_t *po, size_t length) { |
| 430 | |
| 431 | if(length <= 64) { |
| 432 | /* #10.9.3.4 */ |
| 433 | if(length == 0) return -1; |
| 434 | return per_put_few_bits(po, length-1, 7) ? -1 : 0; |
| 435 | } else { |
| 436 | if(aper_put_length(po, -1, length) != (ssize_t)length) { |
| 437 | /* This might happen in case of >16K extensions */ |
| 438 | return -1; |
| 439 | } |
| 440 | } |
| 441 | |
| 442 | return 0; |
| 443 | } |
| 444 | |
| 445 | int |
| 446 | aper_put_nsnnwn(asn_per_outp_t *po, int range, int number) { |
| 447 | int bytes; |
| 448 | |
| 449 | ASN_DEBUG("aper put nsnnwn %d with range %d", number, range); |
| 450 | /* 10.5.7.1 X.691 */ |
| 451 | if(range < 0) { |
| 452 | int i; |
| 453 | for (i = 1; ; i++) { |
| 454 | int bits = 1 << (8 * i); |
| 455 | if (number <= bits) |
| 456 | break; |
| 457 | } |
| 458 | bytes = i; |
| 459 | assert(i <= 4); |
| 460 | } |
| 461 | if(range <= 255) { |
| 462 | int i; |
| 463 | for (i = 1; i <= 8; i++) { |
| 464 | int bits = 1 << i; |
| 465 | if (range <= bits) |
| 466 | break; |
| 467 | } |
| 468 | return per_put_few_bits(po, number, i); |
| 469 | } else if(range == 256) { |
| 470 | bytes = 1; |
| 471 | } else if(range <= 65536) { |
| 472 | bytes = 2; |
| 473 | } else { /* Ranges > 64K */ |
| 474 | int i; |
| 475 | for (i = 1; ; i++) { |
| 476 | int bits = 1 << (8 * i); |
| 477 | if (range <= bits) |
| 478 | break; |
| 479 | } |
| 480 | assert(i <= 4); |
| 481 | bytes = i; |
| 482 | } |
| 483 | if(aper_put_align(po) < 0) /* Aligning on octet */ |
| 484 | return -1; |
| 485 | /* if(per_put_few_bits(po, bytes, 8)) |
| 486 | return -1; |
| 487 | */ |
| 488 | return per_put_few_bits(po, number, 8 * bytes); |
| 489 | } |