1 /* 2 * Copyright 2004 Sun Microsystems, Inc. All rights reserved. 3 * Use is subject to license terms. 4 */ 5 6 #pragma ident "%Z%%M% %I% %E% SMI" 7 8 /* Coding Buffer Implementation */ 9 10 /* 11 Implementation 12 13 Encoding mode 14 15 The encoding buffer is filled from bottom (lowest address) to top 16 (highest address). This makes it easier to expand the buffer, 17 since realloc preserves the existing portion of the buffer. 18 19 Note: Since ASN.1 encoding must be done in reverse, this means 20 that you can't simply memcpy out the buffer data, since it will be 21 backwards. You need to reverse-iterate through it, instead. 22 23 ***This decision may have been a mistake. In practice, the 24 implementation will probably be tuned such that reallocation is 25 rarely necessary. Also, the realloc probably has recopy the 26 buffer itself, so we don't really gain that much by avoiding an 27 explicit copy of the buffer. --Keep this in mind for future reference. 28 29 30 Decoding mode 31 32 The decoding buffer is in normal order and is created by wrapping 33 an asn1buf around a krb5_data structure. 34 */ 35 36 /* Abstraction Function 37 38 Programs should use just pointers to asn1buf's (e.g. asn1buf *mybuf). 39 These pointers must always point to a valid, allocated asn1buf 40 structure or be NULL. 41 42 The contents of the asn1buf represent an octet string. This string 43 begins at base and continues to the octet immediately preceding next. 44 If next == base or mybuf == NULL, then the asn1buf represents an empty 45 octet string. */ 46 47 /* Representation Invariant 48 49 Pointers to asn1buf's must always point to a valid, allocated 50 asn1buf structure or be NULL. 51 52 base points to a valid, allocated octet array or is NULL 53 bound, if non-NULL, points to the last valid octet 54 next >= base 55 next <= bound+2 (i.e. next should be able to step just past the bound, 56 but no further. (The bound should move out in response 57 to being crossed by next.)) */ 58 59 #define ASN1BUF_OMIT_INLINE_FUNCS 60 #include "asn1buf.h" 61 #undef ASN1BUF_OMIT_INLINE_FUNCS 62 #include <stdio.h> 63 #include "asn1_get.h" 64 65 #define asn1_is_eoc(class, num, indef) \ 66 ((class) == UNIVERSAL && !(num) && !(indef)) 67 68 asn1_error_code asn1buf_create(asn1buf **buf) 69 { 70 *buf = (asn1buf*)malloc(sizeof(asn1buf)); 71 if (*buf == NULL) return ENOMEM; 72 (*buf)->base = NULL; 73 (*buf)->bound = NULL; 74 (*buf)->next = NULL; 75 return 0; 76 } 77 78 asn1_error_code asn1buf_wrap_data(asn1buf *buf, const krb5_data *code) 79 { 80 if(code == NULL || code->data == NULL) return ASN1_MISSING_FIELD; 81 buf->next = buf->base = code->data; 82 buf->bound = code->data + code->length - 1; 83 return 0; 84 } 85 86 asn1_error_code asn1buf_imbed(asn1buf *subbuf, const asn1buf *buf, const unsigned int length, const int indef) 87 { 88 subbuf->base = subbuf->next = buf->next; 89 if (!indef) { 90 subbuf->bound = subbuf->base + length - 1; 91 if (subbuf->bound > buf->bound) 92 return ASN1_OVERRUN; 93 } else /* constructed indefinite */ 94 subbuf->bound = buf->bound; 95 return 0; 96 } 97 98 asn1_error_code asn1buf_sync(asn1buf *buf, asn1buf *subbuf, 99 asn1_class asn1class, asn1_tagnum lasttag, 100 unsigned int length, int indef, int seqindef) 101 { 102 asn1_error_code retval; 103 104 if (!seqindef) { 105 /* sequence was encoded as definite length */ 106 buf->next = subbuf->bound + 1; 107 } else if (!asn1_is_eoc(asn1class, lasttag, indef)) { 108 retval = asn1buf_skiptail(subbuf, length, indef); 109 if (retval) 110 return retval; 111 } else { 112 /* We have just read the EOC octets. */ 113 buf->next = subbuf->next; 114 } 115 return 0; 116 } 117 118 asn1_error_code asn1buf_skiptail(asn1buf *buf, const unsigned int length, const int indef) 119 { 120 asn1_error_code retval; 121 taginfo t; 122 int nestlevel; 123 124 nestlevel = 1 + indef; 125 if (!indef) { 126 if (length <= buf->bound - buf->next + 1) 127 buf->next += length; 128 else 129 return ASN1_OVERRUN; 130 } 131 while (nestlevel > 0) { 132 if (buf->bound - buf->next + 1 <= 0) 133 return ASN1_OVERRUN; 134 retval = asn1_get_tag_2(buf, &t); 135 if (retval) return retval; 136 if (!t.indef) { 137 if (t.length <= buf->bound - buf->next + 1) 138 buf->next += t.length; 139 else 140 return ASN1_OVERRUN; 141 } 142 if (t.indef) 143 nestlevel++; 144 if (asn1_is_eoc(t.asn1class, t.tagnum, t.indef)) 145 nestlevel--; /* got an EOC encoding */ 146 } 147 return 0; 148 } 149 150 asn1_error_code asn1buf_destroy(asn1buf **buf) 151 { 152 if (*buf != NULL) { 153 if ((*buf)->base != NULL) free((*buf)->base); 154 free(*buf); 155 *buf = NULL; 156 } 157 return 0; 158 } 159 160 #ifdef asn1buf_insert_octet 161 #undef asn1buf_insert_octet 162 #endif 163 asn1_error_code asn1buf_insert_octet(asn1buf *buf, const int o) 164 { 165 asn1_error_code retval; 166 167 retval = asn1buf_ensure_space(buf,1U); 168 if(retval) return retval; 169 *(buf->next) = (char)o; 170 (buf->next)++; 171 return 0; 172 } 173 174 asn1_error_code asn1buf_insert_octetstring(asn1buf *buf, const unsigned int len, const krb5_octet *s) 175 { 176 asn1_error_code retval; 177 int length; 178 179 retval = asn1buf_ensure_space(buf,len); 180 if(retval) return retval; 181 for(length=1; length<=len; length++,(buf->next)++) 182 *(buf->next) = (char)(s[len-length]); 183 return 0; 184 } 185 186 asn1_error_code asn1buf_insert_charstring(asn1buf *buf, const unsigned int len, const char *s) 187 { 188 asn1_error_code retval; 189 int length; 190 191 retval = asn1buf_ensure_space(buf,len); 192 if(retval) return retval; 193 for(length=1; length<=len; length++,(buf->next)++) 194 *(buf->next) = (char)(s[len-length]); 195 return 0; 196 } 197 198 #undef asn1buf_remove_octet 199 asn1_error_code asn1buf_remove_octet(asn1buf *buf, asn1_octet *o) 200 { 201 if(buf->next > buf->bound) return ASN1_OVERRUN; 202 *o = (asn1_octet)(*((buf->next)++)); 203 return 0; 204 } 205 206 asn1_error_code asn1buf_remove_octetstring(asn1buf *buf, const unsigned int len, asn1_octet **s) 207 { 208 int i; 209 210 if (len > buf->bound + 1 - buf->next) return ASN1_OVERRUN; 211 if (len == 0) { 212 *s = 0; 213 return 0; 214 } 215 *s = (asn1_octet*)malloc(len*sizeof(asn1_octet)); 216 if (*s == NULL) 217 return ENOMEM; 218 for(i=0; i<len; i++) 219 (*s)[i] = (asn1_octet)(buf->next)[i]; 220 buf->next += len; 221 return 0; 222 } 223 224 asn1_error_code asn1buf_remove_charstring(asn1buf *buf, const unsigned int len, char **s) 225 { 226 int i; 227 228 if (len > buf->bound + 1 - buf->next) return ASN1_OVERRUN; 229 if (len == 0) { 230 *s = 0; 231 return 0; 232 } 233 *s = (char*)malloc(len*sizeof(char)); 234 if (*s == NULL) return ENOMEM; 235 for(i=0; i<len; i++) 236 (*s)[i] = (char)(buf->next)[i]; 237 buf->next += len; 238 return 0; 239 } 240 241 int asn1buf_remains(asn1buf *buf, int indef) 242 { 243 int remain; 244 if(buf == NULL || buf->base == NULL) return 0; 245 remain = buf->bound - buf->next +1; 246 if (remain <= 0) return remain; 247 /* 248 * Two 0 octets means the end of an indefinite encoding. 249 */ 250 if (indef && remain >= 2 && !*(buf->next) && !*(buf->next + 1)) 251 return 0; 252 else return remain; 253 } 254 255 asn1_error_code asn12krb5_buf(const asn1buf *buf, krb5_data **code) 256 { 257 int i; 258 *code = (krb5_data*)calloc(1,sizeof(krb5_data)); 259 if(*code == NULL) return ENOMEM; 260 (*code)->magic = KV5M_DATA; 261 (*code)->data = NULL; 262 (*code)->length = 0; 263 (*code)->length = asn1buf_len(buf); 264 (*code)->data = (char*)malloc((((*code)->length)+1)*sizeof(char)); 265 if ((*code)->data == NULL) { 266 free(*code); 267 *code = NULL; 268 return ENOMEM; 269 } 270 for(i=0; i < (*code)->length; i++) 271 ((*code)->data)[i] = (buf->base)[((*code)->length)-i-1]; 272 ((*code)->data)[(*code)->length] = '\0'; 273 return 0; 274 } 275 276 277 278 /* These parse and unparse procedures should be moved out. They're 279 useful only for debugging and superfluous in the production version. */ 280 281 asn1_error_code asn1buf_unparse(const asn1buf *buf, char **s) 282 { 283 if(*s != NULL) free(*s); 284 if(buf == NULL){ 285 *s = malloc(sizeof("<NULL>")); 286 if(*s == NULL) return ENOMEM; 287 strcpy(*s,"<NULL>"); 288 }else if(buf->base == NULL){ 289 *s = malloc(sizeof("<EMPTY>")); 290 if(*s == NULL) return ENOMEM; 291 strcpy(*s,"<EMPTY>"); 292 }else{ 293 unsigned int length = asn1buf_len(buf); 294 int i; 295 296 *s = calloc(length+1, sizeof(char)); 297 if(*s == NULL) return ENOMEM; 298 (*s)[length] = '\0'; 299 for(i=0; i<length; i++) ; 300 /* OLDDECLARG( (*s)[i] = , (buf->base)[length-i-1]) */ 301 } 302 return 0; 303 } 304 305 asn1_error_code asn1buf_hex_unparse(const asn1buf *buf, char **s) 306 { 307 #define hexchar(d) ((d)<=9 ? ('0'+(d)) :\ 308 ((d)<=15 ? ('A'+(d)-10) :\ 309 'X')) 310 311 if(*s != NULL) free(*s); 312 313 if(buf == NULL){ 314 *s = malloc(sizeof("<NULL>")); 315 if(*s == NULL) return ENOMEM; 316 strcpy(*s,"<NULL>"); 317 }else if(buf->base == NULL){ 318 *s = malloc(sizeof("<EMPTY>")); 319 if(*s == NULL) return ENOMEM; 320 strcpy(*s,"<EMPTY>"); 321 }else{ 322 unsigned int length = asn1buf_len(buf); 323 int i; 324 325 *s = malloc(3*length); 326 if(*s == NULL) return ENOMEM; 327 for(i = length-1; i >= 0; i--){ 328 (*s)[3*(length-i-1)] = hexchar(((buf->base)[i]&0xF0)>>4); 329 (*s)[3*(length-i-1)+1] = hexchar((buf->base)[i]&0x0F); 330 (*s)[3*(length-i-1)+2] = ' '; 331 } 332 (*s)[3*length-1] = '\0'; 333 } 334 return 0; 335 } 336 337 /****************************************************************/ 338 /* Private Procedures */ 339 340 #undef asn1buf_size 341 int asn1buf_size(const asn1buf *buf) 342 { 343 if(buf == NULL || buf->base == NULL) return 0; 344 return buf->bound - buf->base + 1; 345 } 346 347 #undef asn1buf_free 348 int asn1buf_free(const asn1buf *buf) 349 { 350 if(buf == NULL || buf->base == NULL) return 0; 351 else return buf->bound - buf->next + 1; 352 } 353 354 #undef asn1buf_ensure_space 355 asn1_error_code asn1buf_ensure_space(asn1buf *buf, const unsigned int amount) 356 { 357 int avail = asn1buf_free(buf); 358 if(avail < amount){ 359 asn1_error_code retval = asn1buf_expand(buf, amount-avail); 360 if(retval) return retval; 361 } 362 return 0; 363 } 364 365 asn1_error_code asn1buf_expand(asn1buf *buf, unsigned int inc) 366 { 367 #define STANDARD_INCREMENT 200 368 int next_offset = buf->next - buf->base; 369 int bound_offset; 370 if (buf->base == NULL) bound_offset = -1; 371 else bound_offset = buf->bound - buf->base; 372 373 if (inc < STANDARD_INCREMENT) 374 inc = STANDARD_INCREMENT; 375 376 if (buf->base == NULL) 377 buf->base = malloc((asn1buf_size(buf)+inc) * sizeof(asn1_octet)); 378 else 379 buf->base = realloc(buf->base, 380 (asn1buf_size(buf)+inc) * sizeof(asn1_octet)); 381 if (buf->base == NULL) return ENOMEM; 382 buf->bound = (buf->base) + bound_offset + inc; 383 buf->next = (buf->base) + next_offset; 384 return 0; 385 } 386 387 #undef asn1buf_len 388 int asn1buf_len(const asn1buf *buf) 389 { 390 return buf->next - buf->base; 391 } 392