Harald Welte | d523a69 | 2015-08-30 23:11:19 +0200 | [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 <asn_internal.h> |
| 6 | #include <errno.h> |
| 7 | |
| 8 | static ssize_t der_write_TL(ber_tlv_tag_t tag, ber_tlv_len_t len, |
| 9 | asn_app_consume_bytes_f *cb, void *app_key, int constructed); |
| 10 | |
| 11 | /* |
| 12 | * The DER encoder of any type. |
| 13 | */ |
| 14 | asn_enc_rval_t |
| 15 | der_encode(asn_TYPE_descriptor_t *type_descriptor, void *struct_ptr, |
| 16 | asn_app_consume_bytes_f *consume_bytes, void *app_key) { |
| 17 | |
| 18 | ASN_DEBUG("DER encoder invoked for %s", |
| 19 | type_descriptor->name); |
| 20 | |
| 21 | /* |
| 22 | * Invoke type-specific encoder. |
| 23 | */ |
| 24 | return type_descriptor->der_encoder(type_descriptor, |
| 25 | struct_ptr, /* Pointer to the destination structure */ |
| 26 | 0, 0, |
| 27 | consume_bytes, app_key); |
| 28 | } |
| 29 | |
| 30 | /* |
| 31 | * Argument type and callback necessary for der_encode_to_buffer(). |
| 32 | */ |
| 33 | typedef struct enc_to_buf_arg { |
| 34 | void *buffer; |
| 35 | size_t left; |
| 36 | } enc_to_buf_arg; |
| 37 | static int encode_to_buffer_cb(const void *buffer, size_t size, void *key) { |
| 38 | enc_to_buf_arg *arg = (enc_to_buf_arg *)key; |
| 39 | |
| 40 | if(arg->left < size) |
| 41 | return -1; /* Data exceeds the available buffer size */ |
| 42 | |
| 43 | memcpy(arg->buffer, buffer, size); |
| 44 | arg->buffer = ((char *)arg->buffer) + size; |
| 45 | arg->left -= size; |
| 46 | |
| 47 | return 0; |
| 48 | } |
| 49 | |
| 50 | /* |
| 51 | * A variant of the der_encode() which encodes the data into the provided buffer |
| 52 | */ |
| 53 | asn_enc_rval_t |
| 54 | der_encode_to_buffer(asn_TYPE_descriptor_t *type_descriptor, void *struct_ptr, |
| 55 | void *buffer, size_t buffer_size) { |
| 56 | enc_to_buf_arg arg; |
| 57 | asn_enc_rval_t ec; |
| 58 | |
| 59 | arg.buffer = buffer; |
| 60 | arg.left = buffer_size; |
| 61 | |
| 62 | ec = type_descriptor->der_encoder(type_descriptor, |
| 63 | struct_ptr, /* Pointer to the destination structure */ |
| 64 | 0, 0, encode_to_buffer_cb, &arg); |
| 65 | if(ec.encoded != -1) { |
| 66 | assert(ec.encoded == (ssize_t)(buffer_size - arg.left)); |
| 67 | /* Return the encoded contents size */ |
| 68 | } |
| 69 | return ec; |
| 70 | } |
| 71 | |
| 72 | |
| 73 | /* |
| 74 | * Write out leading TL[v] sequence according to the type definition. |
| 75 | */ |
| 76 | ssize_t |
| 77 | der_write_tags(asn_TYPE_descriptor_t *sd, |
| 78 | size_t struct_length, |
| 79 | int tag_mode, int last_tag_form, |
| 80 | ber_tlv_tag_t tag, /* EXPLICIT or IMPLICIT tag */ |
| 81 | asn_app_consume_bytes_f *cb, |
| 82 | void *app_key) { |
| 83 | const ber_tlv_tag_t *tags; /* Copy of tags stream */ |
| 84 | int tags_count; /* Number of tags */ |
| 85 | size_t overall_length; |
| 86 | ssize_t *lens; |
| 87 | int i; |
| 88 | |
| 89 | ASN_DEBUG("Writing tags (%s, tm=%d, tc=%d, tag=%s, mtc=%d)", |
| 90 | sd->name, tag_mode, sd->tags_count, |
| 91 | ber_tlv_tag_string(tag), |
| 92 | tag_mode |
| 93 | ?(sd->tags_count+1 |
| 94 | -((tag_mode == -1) && sd->tags_count)) |
| 95 | :sd->tags_count |
| 96 | ); |
| 97 | |
| 98 | if(tag_mode) { |
| 99 | /* |
| 100 | * Instead of doing shaman dance like we do in ber_check_tags(), |
| 101 | * allocate a small array on the stack |
| 102 | * and initialize it appropriately. |
| 103 | */ |
| 104 | int stag_offset; |
| 105 | ber_tlv_tag_t *tags_buf; |
| 106 | tags_buf = (ber_tlv_tag_t *)alloca((sd->tags_count + 1) * sizeof(ber_tlv_tag_t)); |
| 107 | if(!tags_buf) { /* Can fail on !x86 */ |
| 108 | errno = ENOMEM; |
| 109 | return -1; |
| 110 | } |
| 111 | tags_count = sd->tags_count |
| 112 | + 1 /* EXPLICIT or IMPLICIT tag is given */ |
| 113 | - ((tag_mode == -1) && sd->tags_count); |
| 114 | /* Copy tags over */ |
| 115 | tags_buf[0] = tag; |
| 116 | stag_offset = -1 + ((tag_mode == -1) && sd->tags_count); |
| 117 | for(i = 1; i < tags_count; i++) |
| 118 | tags_buf[i] = sd->tags[i + stag_offset]; |
| 119 | tags = tags_buf; |
| 120 | } else { |
| 121 | tags = sd->tags; |
| 122 | tags_count = sd->tags_count; |
| 123 | } |
| 124 | |
| 125 | /* No tags to write */ |
| 126 | if(tags_count == 0) |
| 127 | return 0; |
| 128 | |
| 129 | lens = (ssize_t *)alloca(tags_count * sizeof(lens[0])); |
| 130 | if(!lens) { |
| 131 | errno = ENOMEM; |
| 132 | return -1; |
| 133 | } |
| 134 | |
| 135 | /* |
| 136 | * Array of tags is initialized. |
| 137 | * Now, compute the size of the TLV pairs, from right to left. |
| 138 | */ |
| 139 | overall_length = struct_length; |
| 140 | for(i = tags_count - 1; i >= 0; --i) { |
| 141 | lens[i] = der_write_TL(tags[i], overall_length, 0, 0, 0); |
| 142 | if(lens[i] == -1) return -1; |
| 143 | overall_length += lens[i]; |
| 144 | lens[i] = overall_length - lens[i]; |
| 145 | } |
| 146 | |
| 147 | if(!cb) return overall_length - struct_length; |
| 148 | |
| 149 | ASN_DEBUG("%s %s TL sequence (%d elements)", |
| 150 | cb?"Encoding":"Estimating", sd->name, tags_count); |
| 151 | |
| 152 | /* |
| 153 | * Encode the TL sequence for real. |
| 154 | */ |
| 155 | for(i = 0; i < tags_count; i++) { |
| 156 | ssize_t len; |
| 157 | int _constr; |
| 158 | |
| 159 | /* Check if this tag happens to be constructed */ |
| 160 | _constr = (last_tag_form || i < (tags_count - 1)); |
| 161 | |
| 162 | len = der_write_TL(tags[i], lens[i], cb, app_key, _constr); |
| 163 | if(len == -1) return -1; |
| 164 | } |
| 165 | |
| 166 | return overall_length - struct_length; |
| 167 | } |
| 168 | |
| 169 | static ssize_t |
| 170 | der_write_TL(ber_tlv_tag_t tag, ber_tlv_len_t len, |
| 171 | asn_app_consume_bytes_f *cb, void *app_key, |
| 172 | int constructed) { |
| 173 | uint8_t buf[32]; |
| 174 | size_t size = 0; |
| 175 | int buf_size = cb?sizeof(buf):0; |
| 176 | ssize_t tmp; |
| 177 | |
| 178 | /* Serialize tag (T from TLV) into possibly zero-length buffer */ |
| 179 | tmp = ber_tlv_tag_serialize(tag, buf, buf_size); |
| 180 | if(tmp == -1 || tmp > (ssize_t)sizeof(buf)) return -1; |
| 181 | size += tmp; |
| 182 | |
| 183 | /* Serialize length (L from TLV) into possibly zero-length buffer */ |
| 184 | tmp = der_tlv_length_serialize(len, buf+size, buf_size?buf_size-size:0); |
| 185 | if(tmp == -1) return -1; |
| 186 | size += tmp; |
| 187 | |
| 188 | if(size > sizeof(buf)) |
| 189 | return -1; |
| 190 | |
| 191 | /* |
| 192 | * If callback is specified, invoke it, and check its return value. |
| 193 | */ |
| 194 | if(cb) { |
| 195 | if(constructed) *buf |= 0x20; |
| 196 | if(cb(buf, size, app_key) < 0) |
| 197 | return -1; |
| 198 | } |
| 199 | |
| 200 | return size; |
| 201 | } |