Lev Walkin | 59b176e | 2005-11-26 11:25:14 +0000 | [diff] [blame] | 1 | /* |
Lev Walkin | 20696a4 | 2017-10-17 21:27:33 -0700 | [diff] [blame] | 2 | * Copyright (c) 2005-2017 Lev Walkin <vlm@lionet.info>. All rights reserved. |
Lev Walkin | 59b176e | 2005-11-26 11:25:14 +0000 | [diff] [blame] | 3 | * Redistribution and modifications are permitted subject to BSD license. |
| 4 | */ |
| 5 | #include <asn_system.h> |
Lev Walkin | 9f5bb3a | 2006-08-18 01:46:46 +0000 | [diff] [blame] | 6 | #include <asn_internal.h> |
Lev Walkin | 59b176e | 2005-11-26 11:25:14 +0000 | [diff] [blame] | 7 | #include <per_support.h> |
| 8 | |
Lev Walkin | 59b176e | 2005-11-26 11:25:14 +0000 | [diff] [blame] | 9 | /* |
Lev Walkin | 5d20588 | 2017-08-06 00:03:46 -0700 | [diff] [blame] | 10 | * X.691-201508 #10.9 General rules for encoding a length determinant. |
| 11 | * Get the optionally constrained length "n" from the stream. |
Lev Walkin | 59b176e | 2005-11-26 11:25:14 +0000 | [diff] [blame] | 12 | */ |
| 13 | ssize_t |
Lev Walkin | 9d1b45f | 2017-10-01 17:04:48 -0700 | [diff] [blame] | 14 | uper_get_length(asn_per_data_t *pd, int ebits, size_t lower_bound, |
| 15 | int *repeat) { |
Lev Walkin | 5d20588 | 2017-08-06 00:03:46 -0700 | [diff] [blame] | 16 | ssize_t value; |
Lev Walkin | 59b176e | 2005-11-26 11:25:14 +0000 | [diff] [blame] | 17 | |
Lev Walkin | 5d20588 | 2017-08-06 00:03:46 -0700 | [diff] [blame] | 18 | *repeat = 0; |
Lev Walkin | 59b176e | 2005-11-26 11:25:14 +0000 | [diff] [blame] | 19 | |
Lev Walkin | 5d20588 | 2017-08-06 00:03:46 -0700 | [diff] [blame] | 20 | /* #11.9.4.1 Encoding if constrained (according to effective bits) */ |
| 21 | if(ebits >= 0 && ebits <= 16) { |
Lev Walkin | 9d1b45f | 2017-10-01 17:04:48 -0700 | [diff] [blame] | 22 | value = per_get_few_bits(pd, ebits); |
| 23 | if(value >= 0) value += lower_bound; |
| 24 | return value; |
Lev Walkin | 5d20588 | 2017-08-06 00:03:46 -0700 | [diff] [blame] | 25 | } |
Lev Walkin | 59b176e | 2005-11-26 11:25:14 +0000 | [diff] [blame] | 26 | |
| 27 | value = per_get_few_bits(pd, 8); |
Lev Walkin | 5d20588 | 2017-08-06 00:03:46 -0700 | [diff] [blame] | 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 | return -1; |
| 36 | } |
| 37 | value &= 0x3f; /* this is "m" from X.691, #11.9.3.8 */ |
| 38 | if(value < 1 || value > 4) { |
| 39 | return -1; /* Prohibited by #11.9.3.8 */ |
| 40 | } |
| 41 | *repeat = 1; |
| 42 | return (16384 * value); |
Lev Walkin | 59b176e | 2005-11-26 11:25:14 +0000 | [diff] [blame] | 43 | } |
| 44 | |
| 45 | /* |
Lev Walkin | 5b78e1c | 2007-06-24 06:26:47 +0000 | [diff] [blame] | 46 | * Get the normally small length "n". |
| 47 | * This procedure used to decode length of extensions bit-maps |
| 48 | * for SET and SEQUENCE types. |
| 49 | */ |
| 50 | ssize_t |
| 51 | uper_get_nslength(asn_per_data_t *pd) { |
| 52 | ssize_t length; |
| 53 | |
Lev Walkin | a2987ea | 2007-06-26 23:56:54 +0000 | [diff] [blame] | 54 | ASN_DEBUG("Getting normally small length"); |
| 55 | |
Lev Walkin | 5b78e1c | 2007-06-24 06:26:47 +0000 | [diff] [blame] | 56 | if(per_get_few_bits(pd, 1) == 0) { |
Lev Walkin | a2987ea | 2007-06-26 23:56:54 +0000 | [diff] [blame] | 57 | length = per_get_few_bits(pd, 6) + 1; |
| 58 | if(length <= 0) return -1; |
Lev Walkin | fe1ffaf | 2010-10-25 21:07:59 -0700 | [diff] [blame] | 59 | ASN_DEBUG("l=%d", (int)length); |
Lev Walkin | a2987ea | 2007-06-26 23:56:54 +0000 | [diff] [blame] | 60 | return length; |
Lev Walkin | 5b78e1c | 2007-06-24 06:26:47 +0000 | [diff] [blame] | 61 | } else { |
| 62 | int repeat; |
Lev Walkin | 9d1b45f | 2017-10-01 17:04:48 -0700 | [diff] [blame] | 63 | length = uper_get_length(pd, -1, 0, &repeat); |
Lev Walkin | 5b78e1c | 2007-06-24 06:26:47 +0000 | [diff] [blame] | 64 | if(length >= 0 && !repeat) return length; |
| 65 | return -1; /* Error, or do not support >16K extensions */ |
| 66 | } |
| 67 | } |
| 68 | |
| 69 | /* |
Lev Walkin | 59b176e | 2005-11-26 11:25:14 +0000 | [diff] [blame] | 70 | * Get the normally small non-negative whole number. |
| 71 | * X.691, #10.6 |
| 72 | */ |
| 73 | ssize_t |
| 74 | uper_get_nsnnwn(asn_per_data_t *pd) { |
| 75 | ssize_t value; |
| 76 | |
| 77 | value = per_get_few_bits(pd, 7); |
| 78 | if(value & 64) { /* implicit (value < 0) */ |
| 79 | value &= 63; |
| 80 | value <<= 2; |
| 81 | value |= per_get_few_bits(pd, 2); |
| 82 | if(value & 128) /* implicit (value < 0) */ |
| 83 | return -1; |
| 84 | if(value == 0) |
| 85 | return 0; |
| 86 | if(value >= 3) |
| 87 | return -1; |
| 88 | value = per_get_few_bits(pd, 8 * value); |
| 89 | return value; |
| 90 | } |
| 91 | |
| 92 | return value; |
| 93 | } |
Lev Walkin | 523de9e | 2006-08-18 01:34:18 +0000 | [diff] [blame] | 94 | |
| 95 | /* |
Lev Walkin | 6c52784 | 2014-02-09 04:34:54 -0800 | [diff] [blame] | 96 | * X.691-11/2008, #11.6 |
| 97 | * Encoding of a normally small non-negative whole number |
Lev Walkin | 523de9e | 2006-08-18 01:34:18 +0000 | [diff] [blame] | 98 | */ |
| 99 | int |
| 100 | uper_put_nsnnwn(asn_per_outp_t *po, int n) { |
| 101 | int bytes; |
| 102 | |
| 103 | if(n <= 63) { |
| 104 | if(n < 0) return -1; |
| 105 | return per_put_few_bits(po, n, 7); |
| 106 | } |
| 107 | if(n < 256) |
| 108 | bytes = 1; |
| 109 | else if(n < 65536) |
| 110 | bytes = 2; |
| 111 | else if(n < 256 * 65536) |
| 112 | bytes = 3; |
| 113 | else |
| 114 | return -1; /* This is not a "normally small" value */ |
| 115 | if(per_put_few_bits(po, bytes, 8)) |
| 116 | return -1; |
| 117 | |
| 118 | return per_put_few_bits(po, n, 8 * bytes); |
| 119 | } |
| 120 | |
| 121 | |
Lev Walkin | 6c52784 | 2014-02-09 04:34:54 -0800 | [diff] [blame] | 122 | /* X.691-2008/11, #11.5.6 -> #11.3 */ |
| 123 | int uper_get_constrained_whole_number(asn_per_data_t *pd, unsigned long *out_value, int nbits) { |
| 124 | unsigned long lhalf; /* Lower half of the number*/ |
| 125 | long half; |
| 126 | |
| 127 | if(nbits <= 31) { |
| 128 | half = per_get_few_bits(pd, nbits); |
| 129 | if(half < 0) return -1; |
| 130 | *out_value = half; |
| 131 | return 0; |
| 132 | } |
| 133 | |
| 134 | if((size_t)nbits > 8 * sizeof(*out_value)) |
| 135 | return -1; /* RANGE */ |
| 136 | |
| 137 | half = per_get_few_bits(pd, 31); |
| 138 | if(half < 0) return -1; |
| 139 | |
| 140 | if(uper_get_constrained_whole_number(pd, &lhalf, nbits - 31)) |
| 141 | return -1; |
| 142 | |
| 143 | *out_value = ((unsigned long)half << (nbits - 31)) | lhalf; |
| 144 | return 0; |
| 145 | } |
| 146 | |
| 147 | |
| 148 | /* X.691-2008/11, #11.5.6 -> #11.3 */ |
Lev Walkin | cc6a76b | 2017-10-07 16:23:16 -0700 | [diff] [blame] | 149 | int |
| 150 | uper_put_constrained_whole_number_u(asn_per_outp_t *po, unsigned long v, |
| 151 | int nbits) { |
| 152 | if(nbits <= 31) { |
| 153 | return per_put_few_bits(po, v, nbits); |
| 154 | } else { |
| 155 | /* Put higher portion first, followed by lower 31-bit */ |
| 156 | if(uper_put_constrained_whole_number_u(po, v >> 31, nbits - 31)) |
| 157 | return -1; |
| 158 | return per_put_few_bits(po, v, 31); |
| 159 | } |
Lev Walkin | 6c52784 | 2014-02-09 04:34:54 -0800 | [diff] [blame] | 160 | } |
| 161 | |
Lev Walkin | 523de9e | 2006-08-18 01:34:18 +0000 | [diff] [blame] | 162 | /* |
Lev Walkin | 9d1b45f | 2017-10-01 17:04:48 -0700 | [diff] [blame] | 163 | * X.691 (08/2015) #11.9 "General rules for encoding a length determinant" |
Lev Walkin | 523de9e | 2006-08-18 01:34:18 +0000 | [diff] [blame] | 164 | * Put the length "n" (or part of it) into the stream. |
| 165 | */ |
| 166 | ssize_t |
Lev Walkin | 5d947a8 | 2017-10-03 01:04:03 -0700 | [diff] [blame] | 167 | uper_put_length(asn_per_outp_t *po, size_t length, int *need_eom) { |
| 168 | int dummy = 0; |
| 169 | if(!need_eom) need_eom = &dummy; |
Lev Walkin | 523de9e | 2006-08-18 01:34:18 +0000 | [diff] [blame] | 170 | |
Lev Walkin | 5d947a8 | 2017-10-03 01:04:03 -0700 | [diff] [blame] | 171 | if(length <= 127) { /* #11.9.3.6 */ |
| 172 | *need_eom = 0; |
Lev Walkin | 9d1b45f | 2017-10-01 17:04:48 -0700 | [diff] [blame] | 173 | return per_put_few_bits(po, length, 8) |
| 174 | ? -1 : (ssize_t)length; |
Lev Walkin | 5d947a8 | 2017-10-03 01:04:03 -0700 | [diff] [blame] | 175 | } else if(length < 16384) { /* #10.9.3.7 */ |
| 176 | *need_eom = 0; |
Lev Walkin | 9d1b45f | 2017-10-01 17:04:48 -0700 | [diff] [blame] | 177 | return per_put_few_bits(po, length|0x8000, 16) |
| 178 | ? -1 : (ssize_t)length; |
Lev Walkin | 5d947a8 | 2017-10-03 01:04:03 -0700 | [diff] [blame] | 179 | } |
Lev Walkin | 523de9e | 2006-08-18 01:34:18 +0000 | [diff] [blame] | 180 | |
Lev Walkin | 5d947a8 | 2017-10-03 01:04:03 -0700 | [diff] [blame] | 181 | *need_eom = 0 == (length & 16383); |
Lev Walkin | 9d1b45f | 2017-10-01 17:04:48 -0700 | [diff] [blame] | 182 | length >>= 14; |
Lev Walkin | 5d947a8 | 2017-10-03 01:04:03 -0700 | [diff] [blame] | 183 | if(length > 4) { |
| 184 | *need_eom = 0; |
| 185 | length = 4; |
| 186 | } |
Lev Walkin | 523de9e | 2006-08-18 01:34:18 +0000 | [diff] [blame] | 187 | |
Lev Walkin | 9d1b45f | 2017-10-01 17:04:48 -0700 | [diff] [blame] | 188 | return per_put_few_bits(po, 0xC0 | length, 8) |
| 189 | ? -1 : (ssize_t)(length << 14); |
| 190 | |
Lev Walkin | 523de9e | 2006-08-18 01:34:18 +0000 | [diff] [blame] | 191 | } |
| 192 | |
Lev Walkin | 62258e2 | 2007-06-23 23:50:25 +0000 | [diff] [blame] | 193 | |
| 194 | /* |
| 195 | * Put the normally small length "n" into the stream. |
| 196 | * This procedure used to encode length of extensions bit-maps |
| 197 | * for SET and SEQUENCE types. |
| 198 | */ |
| 199 | int |
| 200 | uper_put_nslength(asn_per_outp_t *po, size_t length) { |
Lev Walkin | 5d947a8 | 2017-10-03 01:04:03 -0700 | [diff] [blame] | 201 | if(length <= 64) { |
| 202 | /* #11.9.3.4 */ |
| 203 | if(length == 0) return -1; |
| 204 | return per_put_few_bits(po, length - 1, 7) ? -1 : 0; |
| 205 | } else { |
| 206 | int need_eom = 0; |
| 207 | if(uper_put_length(po, length, &need_eom) != (ssize_t)length |
| 208 | || need_eom) { |
| 209 | /* This might happen in case of >16K extensions */ |
| 210 | return -1; |
| 211 | } |
| 212 | } |
Lev Walkin | 62258e2 | 2007-06-23 23:50:25 +0000 | [diff] [blame] | 213 | |
Lev Walkin | 5d947a8 | 2017-10-03 01:04:03 -0700 | [diff] [blame] | 214 | return 0; |
Lev Walkin | 62258e2 | 2007-06-23 23:50:25 +0000 | [diff] [blame] | 215 | } |
| 216 | |
Lev Walkin | cc6a76b | 2017-10-07 16:23:16 -0700 | [diff] [blame] | 217 | static int |
| 218 | per__long_range(long lb, long ub, unsigned long *range_r) { |
| 219 | unsigned long bounds_range; |
| 220 | if((ub < 0) == (lb < 0)) { |
| 221 | bounds_range = ub - lb; |
| 222 | } else if(lb < 0) { |
| 223 | assert(ub >= 0); |
| 224 | bounds_range = 1 + ((unsigned long)ub + (unsigned long)-(lb + 1)); |
| 225 | } else { |
| 226 | assert(!"Unreachable"); |
| 227 | return -1; |
| 228 | } |
| 229 | *range_r = bounds_range; |
| 230 | return 0; |
| 231 | } |
| 232 | |
| 233 | int |
| 234 | per_long_range_rebase(long v, long lb, long ub, unsigned long *output) { |
| 235 | unsigned long range; |
| 236 | |
| 237 | assert(lb <= ub); |
| 238 | |
| 239 | if(v < lb || v > ub || per__long_range(lb, ub, &range) < 0) { |
| 240 | /* Range error. */ |
| 241 | return -1; |
| 242 | } |
| 243 | |
| 244 | /* |
| 245 | * Fundamentally what we're doing is returning (v-lb). |
| 246 | * However, this triggers undefined behavior when the word width |
| 247 | * of signed (v) is the same as the size of unsigned (*output). |
| 248 | * In practice, it triggers the UndefinedSanitizer. Therefore we shall |
| 249 | * compute the ranges accurately to avoid C's undefined behavior. |
| 250 | */ |
| 251 | if((v < 0) == (lb < 0)) { |
| 252 | *output = v-lb; |
| 253 | return 0; |
| 254 | } else if(v < 0) { |
| 255 | unsigned long rebased = 1 + (unsigned long)-(v+1) + (unsigned long)lb; |
| 256 | assert(rebased <= range); /* By construction */ |
| 257 | *output = rebased; |
| 258 | return 0; |
| 259 | } else if(lb < 0) { |
| 260 | unsigned long rebased = 1 + (unsigned long)-(lb+1) + (unsigned long)v; |
| 261 | assert(rebased <= range); /* By construction */ |
| 262 | *output = rebased; |
| 263 | return 0; |
| 264 | } else { |
| 265 | assert(!"Unreachable"); |
| 266 | return -1; |
| 267 | } |
| 268 | } |
| 269 | |
| 270 | int |
| 271 | per_long_range_unrebase(unsigned long inp, long lb, long ub, long *outp) { |
| 272 | unsigned long range; |
| 273 | |
| 274 | if(per__long_range(lb, ub, &range) != 0) { |
| 275 | return -1; |
| 276 | } |
| 277 | |
| 278 | if(inp > range) { |
| 279 | /* |
| 280 | * We can encode something in the given number of bits that technically |
| 281 | * exceeds the range. This is an avenue for security errors, |
| 282 | * so we don't allow that. |
| 283 | */ |
| 284 | return -1; |
| 285 | } |
| 286 | |
| 287 | if(inp <= LONG_MAX) { |
| 288 | *outp = (long)inp + lb; |
| 289 | } else { |
| 290 | *outp = (lb + LONG_MAX + 1) + (long)((inp - LONG_MAX) - 1); |
| 291 | } |
| 292 | |
| 293 | return 0; |
| 294 | } |