vlm | fa67ddc | 2004-06-03 03:38:44 +0000 | [diff] [blame] | 1 | /*- |
| 2 | * Copyright (c) 2003, 2004 Lev Walkin <vlm@lionet.info>. All rights reserved. |
| 3 | * Redistribution and modifications are permitted subject to BSD license. |
| 4 | */ |
| 5 | #include <constr_TYPE.h> |
| 6 | #include <ber_tlv_length.h> |
| 7 | #include <ber_tlv_tag.h> |
| 8 | |
| 9 | ssize_t |
| 10 | ber_fetch_length(int _is_constructed, void *bufptr, size_t size, |
| 11 | ber_tlv_len_t *len_r) { |
vlm | da67468 | 2004-08-11 09:07:36 +0000 | [diff] [blame] | 12 | uint8_t *buf = (uint8_t *)bufptr; |
vlm | fa67ddc | 2004-06-03 03:38:44 +0000 | [diff] [blame] | 13 | unsigned oct; |
| 14 | |
| 15 | if(size == 0) |
| 16 | return 0; /* Want more */ |
| 17 | |
| 18 | oct = *(uint8_t *)buf; |
| 19 | if((oct & 0x80) == 0) { |
| 20 | /* |
| 21 | * Short definite length. |
| 22 | */ |
vlm | 15f28cb | 2004-08-19 18:10:27 +0000 | [diff] [blame] | 23 | *len_r = oct; /* & 0x7F */ |
vlm | fa67ddc | 2004-06-03 03:38:44 +0000 | [diff] [blame] | 24 | return 1; |
| 25 | } else { |
| 26 | ber_tlv_len_t len; |
vlm | b42843a | 2004-06-05 08:17:50 +0000 | [diff] [blame] | 27 | size_t skipped; |
vlm | fa67ddc | 2004-06-03 03:38:44 +0000 | [diff] [blame] | 28 | |
| 29 | if(_is_constructed && oct == 0x80) { |
| 30 | *len_r = -1; /* Indefinite length */ |
| 31 | return 1; |
| 32 | } |
| 33 | |
| 34 | if(oct == 0xff) { |
| 35 | /* Reserved in standard for future use. */ |
| 36 | return -1; |
| 37 | } |
| 38 | |
| 39 | oct &= 0x7F; /* Leave only the 7 LS bits */ |
| 40 | for(len = 0, buf++, skipped = 1; |
vlm | 15f28cb | 2004-08-19 18:10:27 +0000 | [diff] [blame] | 41 | oct && (++skipped <= size); buf++, oct--) { |
vlm | fa67ddc | 2004-06-03 03:38:44 +0000 | [diff] [blame] | 42 | |
| 43 | len = (len << 8) | *buf; |
| 44 | if(len < 0 |
| 45 | || (len >> ((8 * sizeof(len)) - 8) && oct > 1)) { |
| 46 | /* |
| 47 | * Too large length value. |
| 48 | */ |
| 49 | return -1; |
| 50 | } |
| 51 | } |
| 52 | |
| 53 | if(oct == 0) { |
| 54 | *len_r = len; |
| 55 | return skipped; |
| 56 | } |
| 57 | |
| 58 | return 0; /* Want more */ |
| 59 | } |
| 60 | |
| 61 | } |
| 62 | |
| 63 | ssize_t |
| 64 | ber_skip_length(int _is_constructed, void *ptr, size_t size) { |
| 65 | ber_tlv_len_t vlen; /* Length of V in TLV */ |
| 66 | ssize_t tl; /* Length of L in TLV */ |
| 67 | ssize_t ll; /* Length of L in TLV */ |
vlm | b42843a | 2004-06-05 08:17:50 +0000 | [diff] [blame] | 68 | size_t skip; |
vlm | fa67ddc | 2004-06-03 03:38:44 +0000 | [diff] [blame] | 69 | |
| 70 | /* |
| 71 | * Determine the size of L in TLV. |
| 72 | */ |
| 73 | ll = ber_fetch_length(_is_constructed, ptr, size, &vlen); |
| 74 | if(ll <= 0) return ll; |
| 75 | |
| 76 | /* |
| 77 | * Definite length. |
| 78 | */ |
| 79 | if(vlen >= 0) { |
| 80 | skip = ll + vlen; |
| 81 | if(skip > size) |
| 82 | return 0; /* Want more */ |
| 83 | return skip; |
| 84 | } |
| 85 | |
| 86 | /* |
| 87 | * Indefinite length! |
| 88 | */ |
| 89 | ASN_DEBUG("Skipping indefinite length"); |
vlm | 1ff928d | 2004-08-11 08:10:13 +0000 | [diff] [blame] | 90 | for(skip = ll, (char *)ptr += ll, size -= ll;;) { |
vlm | fa67ddc | 2004-06-03 03:38:44 +0000 | [diff] [blame] | 91 | ber_tlv_tag_t tag; |
| 92 | |
| 93 | /* Fetch the tag */ |
| 94 | tl = ber_fetch_tag(ptr, size, &tag); |
| 95 | if(tl <= 0) return tl; |
| 96 | |
| 97 | ll = ber_skip_length(BER_TLV_CONSTRUCTED(ptr), |
vlm | 1ff928d | 2004-08-11 08:10:13 +0000 | [diff] [blame] | 98 | (char *)ptr + tl, size - tl); |
vlm | fa67ddc | 2004-06-03 03:38:44 +0000 | [diff] [blame] | 99 | if(ll <= 0) return ll; |
| 100 | |
| 101 | skip += tl + ll; |
| 102 | |
| 103 | /* |
| 104 | * This may be the end of the indefinite length structure, |
| 105 | * two consecutive 0 octets. |
| 106 | * Check if it is true. |
| 107 | */ |
| 108 | if(((uint8_t *)ptr)[0] == 0 |
| 109 | && ((uint8_t *)ptr)[1] == 0) |
| 110 | return skip; |
| 111 | |
vlm | 1ff928d | 2004-08-11 08:10:13 +0000 | [diff] [blame] | 112 | (char *)ptr += tl + ll; |
vlm | fa67ddc | 2004-06-03 03:38:44 +0000 | [diff] [blame] | 113 | size -= tl + ll; |
| 114 | } |
| 115 | |
| 116 | /* UNREACHABLE */ |
| 117 | } |
| 118 | |
| 119 | ssize_t |
| 120 | der_tlv_length_serialize(ber_tlv_len_t len, void *bufp, size_t size) { |
vlm | 15f28cb | 2004-08-19 18:10:27 +0000 | [diff] [blame] | 121 | size_t required_size; /* Size of len encoding */ |
vlm | da67468 | 2004-08-11 09:07:36 +0000 | [diff] [blame] | 122 | uint8_t *buf = (uint8_t *)bufp; |
vlm | fa67ddc | 2004-06-03 03:38:44 +0000 | [diff] [blame] | 123 | uint8_t *end; |
vlm | 15f28cb | 2004-08-19 18:10:27 +0000 | [diff] [blame] | 124 | size_t i; |
vlm | fa67ddc | 2004-06-03 03:38:44 +0000 | [diff] [blame] | 125 | |
| 126 | if(len <= 127) { |
| 127 | /* Encoded in 1 octet */ |
| 128 | if(size) *buf = len; |
| 129 | return 1; |
| 130 | } |
| 131 | |
| 132 | /* |
| 133 | * Compute the size of the subsequent bytes. |
| 134 | */ |
vlm | 15f28cb | 2004-08-19 18:10:27 +0000 | [diff] [blame] | 135 | for(required_size = 1, i = 8; i < 8 * sizeof(len); i += 8) { |
| 136 | if(len >> i) |
| 137 | required_size++; |
| 138 | else |
| 139 | break; |
vlm | fa67ddc | 2004-06-03 03:38:44 +0000 | [diff] [blame] | 140 | } |
| 141 | |
vlm | 15f28cb | 2004-08-19 18:10:27 +0000 | [diff] [blame] | 142 | if(size < required_size) |
| 143 | return required_size + 1; |
| 144 | |
| 145 | *buf++ = 0x80 | required_size; /* Length of the encoding */ |
vlm | fa67ddc | 2004-06-03 03:38:44 +0000 | [diff] [blame] | 146 | |
| 147 | /* |
| 148 | * Produce the len encoding, space permitting. |
| 149 | */ |
vlm | 15f28cb | 2004-08-19 18:10:27 +0000 | [diff] [blame] | 150 | end = buf + required_size; |
| 151 | for(i -= 8; buf < end; i -= 8, buf++) |
| 152 | *buf = (len >> i); |
vlm | fa67ddc | 2004-06-03 03:38:44 +0000 | [diff] [blame] | 153 | |
vlm | 15f28cb | 2004-08-19 18:10:27 +0000 | [diff] [blame] | 154 | return required_size + 1; |
vlm | fa67ddc | 2004-06-03 03:38:44 +0000 | [diff] [blame] | 155 | } |
| 156 | |