crypto/asn1/asn1_lib.c

   1 /*
   2  * Copyright 1995-2021 The OpenSSL Project Authors. All Rights Reserved.
   3  *
   4  * Licensed under the Apache License 2.0 (the "License").  You may not use
   5  * this file except in compliance with the License.  You can obtain a copy
   6  * in the file LICENSE in the source distribution or at
   7  * https://www.openssl.org/source/license.html
   8  */
   9
  10 #include <stdio.h>
  11 #include <limits.h>
  12 #include "internal/cryptlib.h"
  13 #include <openssl/asn1.h>
  14 #include "asn1_local.h"
  15
  16 static int asn1_get_length(const unsigned char **pp, int *inf, long *rl,
  17                            long max);
  18 static void asn1_put_length(unsigned char **pp, int length);
  19
  20 static int _asn1_check_infinite_end(const unsigned char **p, long len)
  21 {
  22     /*
  23      * If there is 0 or 1 byte left, the length check should pick things up
  24      */
  25     if (len <= 0) {
  26         return 1;
  27     } else {
  28         if ((len >= 2) && ((*p)[0] == 0) && ((*p)[1] == 0)) {
  29             (*p) += 2;
  30             return 1;
  31         }
  32     }
  33     return 0;
  34 }
  35
  36 int ASN1_check_infinite_end(unsigned char **p, long len)
  37 {
  38     return _asn1_check_infinite_end((const unsigned char **)p, len);
  39 }
  40
  41 int ASN1_const_check_infinite_end(const unsigned char **p, long len)
  42 {
  43     return _asn1_check_infinite_end(p, len);
  44 }
  45
  46 int ASN1_get_object(const unsigned char **pp, long *plength, int *ptag,
  47                     int *pclass, long omax)
  48 {
  49     int i, ret;
  50     long len;
  51     const unsigned char *p = *pp;
  52     int tag, xclass, inf;
  53     long max = omax;
  54
  55     if (!max)
  56         goto err;
  57     ret = (*p & V_ASN1_CONSTRUCTED);
  58     xclass = (*p & V_ASN1_PRIVATE);
  59     i = *p & V_ASN1_PRIMITIVE_TAG;
  60     if (i == V_ASN1_PRIMITIVE_TAG) { /* high-tag */
  61         p++;
  62         if (--max == 0)
  63             goto err;
  64         len = 0;
  65         while (*p & 0x80) {
  66             len <<= 7L;
  67             len |= *(p++) & 0x7f;
  68             if (--max == 0)
  69                 goto err;
  70             if (len > (INT_MAX >> 7L))
  71                 goto err;
  72         }
  73         len <<= 7L;
  74         len |= *(p++) & 0x7f;
  75         tag = (int)len;
  76         if (--max == 0)
  77             goto err;
  78     } else {
  79         tag = i;
  80         p++;
  81         if (--max == 0)
  82             goto err;
  83     }
  84     *ptag = tag;
  85     *pclass = xclass;
  86     if (!asn1_get_length(&p, &inf, plength, max))
  87         goto err;
  88
  89     if (inf && !(ret & V_ASN1_CONSTRUCTED))
  90         goto err;
  91
  92     if (*plength > (omax - (p - *pp))) {
  93         ERR_raise(ERR_LIB_ASN1, ASN1_R_TOO_LONG);
  94         /*
  95          * Set this so that even if things are not long enough the values are
  96          * set correctly
  97          */
  98         ret |= 0x80;
  99     }
 100     *pp = p;
 101     return ret | inf;
 102  err:
 103     ERR_raise(ERR_LIB_ASN1, ASN1_R_HEADER_TOO_LONG);
 104     return 0x80;
 105 }
 106
 107 /*
 108  * Decode a length field.
 109  * The short form is a single byte defining a length 0 - 127.
 110  * The long form is a byte 0 - 127 with the top bit set and this indicates
 111  * the number of following octets that contain the length.  These octets
 112  * are stored most significant digit first.
 113  */
 114 static int asn1_get_length(const unsigned char **pp, int *inf, long *rl,
 115                            long max)
 116 {
 117     const unsigned char *p = *pp;
 118     unsigned long ret = 0;
 119     int i;
 120
 121     if (max-- < 1)
 122         return 0;
 123     if (*p == 0x80) {
 124         *inf = 1;
 125         p++;
 126     } else {
 127         *inf = 0;
 128         i = *p & 0x7f;
 129         if (*p++ & 0x80) {
 130             if (max < i + 1)
 131                 return 0;
 132             /* Skip leading zeroes */
 133             while (i > 0 && *p == 0) {
 134                 p++;
 135                 i--;
 136             }
 137             if (i > (int)sizeof(long))
 138                 return 0;
 139             while (i > 0) {
 140                 ret <<= 8;
 141                 ret |= *p++;
 142                 i--;
 143             }
 144             if (ret > LONG_MAX)
 145                 return 0;
 146         } else {
 147             ret = i;
 148         }
 149     }
 150     *pp = p;
 151     *rl = (long)ret;
 152     return 1;
 153 }
 154
 155 /*
 156  * class 0 is constructed constructed == 2 for indefinite length constructed
 157  */
 158 void ASN1_put_object(unsigned char **pp, int constructed, int length, int tag,
 159                      int xclass)
 160 {
 161     unsigned char *p = *pp;
 162     int i, ttag;
 163
 164     i = (constructed) ? V_ASN1_CONSTRUCTED : 0;
 165     i |= (xclass & V_ASN1_PRIVATE);
 166     if (tag < 31) {
 167         *(p++) = i | (tag & V_ASN1_PRIMITIVE_TAG);
 168     } else {
 169         *(p++) = i | V_ASN1_PRIMITIVE_TAG;
 170         for (i = 0, ttag = tag; ttag > 0; i++)
 171             ttag >>= 7;
 172         ttag = i;
 173         while (i-- > 0) {
 174             p[i] = tag & 0x7f;
 175             if (i != (ttag - 1))
 176                 p[i] |= 0x80;
 177             tag >>= 7;
 178         }
 179         p += ttag;
 180     }
 181     if (constructed == 2)
 182         *(p++) = 0x80;
 183     else
 184         asn1_put_length(&p, length);
 185     *pp = p;
 186 }
 187
 188 int ASN1_put_eoc(unsigned char **pp)
 189 {
 190     unsigned char *p = *pp;
 191
 192     *p++ = 0;
 193     *p++ = 0;
 194     *pp = p;
 195     return 2;
 196 }
 197
 198 static void asn1_put_length(unsigned char **pp, int length)
 199 {
 200     unsigned char *p = *pp;
 201     int i, len;
 202
 203     if (length <= 127) {
 204         *(p++) = (unsigned char)length;
 205     } else {
 206         len = length;
 207         for (i = 0; len > 0; i++)
 208             len >>= 8;
 209         *(p++) = i | 0x80;
 210         len = i;
 211         while (i-- > 0) {
 212             p[i] = length & 0xff;
 213             length >>= 8;
 214         }
 215         p += len;
 216     }
 217     *pp = p;
 218 }
 219
 220 int ASN1_object_size(int constructed, int length, int tag)
 221 {
 222     int ret = 1;
 223
 224     if (length < 0)
 225         return -1;
 226     if (tag >= 31) {
 227         while (tag > 0) {
 228             tag >>= 7;
 229             ret++;
 230         }
 231     }
 232     if (constructed == 2) {
 233         ret += 3;
 234     } else {
 235         ret++;
 236         if (length > 127) {
 237             int tmplen = length;
 238             while (tmplen > 0) {
 239                 tmplen >>= 8;
 240                 ret++;
 241             }
 242         }
 243     }
 244     if (ret >= INT_MAX - length)
 245         return -1;
 246     return ret + length;
 247 }
 248
 249 int ASN1_STRING_copy(ASN1_STRING *dst, const ASN1_STRING *str)
 250 {
 251     if (str == NULL)
 252         return 0;
 253     dst->type = str->type;
 254     if (!ASN1_STRING_set(dst, str->data, str->length))
 255         return 0;
 256     /* Copy flags but preserve embed value */
 257     dst->flags &= ASN1_STRING_FLAG_EMBED;
 258     dst->flags |= str->flags & ~ASN1_STRING_FLAG_EMBED;
 259     return 1;
 260 }
 261
 262 ASN1_STRING *ASN1_STRING_dup(const ASN1_STRING *str)
 263 {
 264     ASN1_STRING *ret;
 265
 266     if (!str)
 267         return NULL;
 268     ret = ASN1_STRING_new();
 269     if (ret == NULL)
 270         return NULL;
 271     if (!ASN1_STRING_copy(ret, str)) {
 272         ASN1_STRING_free(ret);
 273         return NULL;
 274     }
 275     return ret;
 276 }
 277
 278 int ASN1_STRING_set(ASN1_STRING *str, const void *_data, int len_in)
 279 {
 280     unsigned char *c;
 281     const char *data = _data;
 282     size_t len;
 283
 284     if (len_in < 0) {
 285         if (data == NULL)
 286             return 0;
 287         len = strlen(data);
 288     } else {
 289         len = (size_t)len_in;
 290     }
 291     /*
 292      * Verify that the length fits within an integer for assignment to
 293      * str->length below.  The additional 1 is subtracted to allow for the
 294      * '\0' terminator even though this isn't strictly necessary.
 295      */
 296     if (len > INT_MAX - 1) {
 297         ERR_raise(ERR_LIB_ASN1, ASN1_R_TOO_LARGE);
 298         return 0;
 299     }
 300     if ((size_t)str->length <= len || str->data == NULL) {
 301         c = str->data;
 302         str->data = OPENSSL_realloc(c, len + 1);
 303         if (str->data == NULL) {
 304             ERR_raise(ERR_LIB_ASN1, ERR_R_MALLOC_FAILURE);
 305             str->data = c;
 306             return 0;
 307         }
 308     }
 309     str->length = len;
 310     if (data != NULL) {
 311         memcpy(str->data, data, len);
 312         /* an allowance for strings :-) */
 313         str->data[len] = '\0';
 314     }
 315     return 1;
 316 }
 317
 318 void ASN1_STRING_set0(ASN1_STRING *str, void *data, int len)
 319 {
 320     OPENSSL_free(str->data);
 321     str->data = data;
 322     str->length = len;
 323 }
 324
 325 ASN1_STRING *ASN1_STRING_new(void)
 326 {
 327     return ASN1_STRING_type_new(V_ASN1_OCTET_STRING);
 328 }
 329
 330 ASN1_STRING *ASN1_STRING_type_new(int type)
 331 {
 332     ASN1_STRING *ret;
 333
 334     ret = OPENSSL_zalloc(sizeof(*ret));
 335     if (ret == NULL) {
 336         ERR_raise(ERR_LIB_ASN1, ERR_R_MALLOC_FAILURE);
 337         return NULL;
 338     }
 339     ret->type = type;
 340     return ret;
 341 }
 342
 343 void ossl_asn1_string_embed_free(ASN1_STRING *a, int embed)
 344 {
 345     if (a == NULL)
 346         return;
 347     if (!(a->flags & ASN1_STRING_FLAG_NDEF))
 348         OPENSSL_free(a->data);
 349     if (embed == 0)
 350         OPENSSL_free(a);
 351 }
 352
 353 void ASN1_STRING_free(ASN1_STRING *a)
 354 {
 355     if (a == NULL)
 356         return;
 357     ossl_asn1_string_embed_free(a, a->flags & ASN1_STRING_FLAG_EMBED);
 358 }
 359
 360 void ASN1_STRING_clear_free(ASN1_STRING *a)
 361 {
 362     if (a == NULL)
 363         return;
 364     if (a->data && !(a->flags & ASN1_STRING_FLAG_NDEF))
 365         OPENSSL_cleanse(a->data, a->length);
 366     ASN1_STRING_free(a);
 367 }
 368
 369 int ASN1_STRING_cmp(const ASN1_STRING *a, const ASN1_STRING *b)
 370 {
 371     int i;
 372
 373     i = (a->length - b->length);
 374     if (i == 0) {
 375         i = memcmp(a->data, b->data, a->length);
 376         if (i == 0)
 377             return a->type - b->type;
 378         else
 379             return i;
 380     } else {
 381         return i;
 382     }
 383 }
 384
 385 int ASN1_STRING_length(const ASN1_STRING *x)
 386 {
 387     return x->length;
 388 }
 389
 390 #ifndef OPENSSL_NO_DEPRECATED_3_0
 391 void ASN1_STRING_length_set(ASN1_STRING *x, int len)
 392 {
 393     x->length = len;
 394 }
 395 #endif
 396
 397 int ASN1_STRING_type(const ASN1_STRING *x)
 398 {
 399     return x->type;
 400 }
 401
 402 const unsigned char *ASN1_STRING_get0_data(const ASN1_STRING *x)
 403 {
 404     return x->data;
 405 }
 406
 407 #ifndef OPENSSL_NO_DEPRECATED_1_1_0
 408 unsigned char *ASN1_STRING_data(ASN1_STRING *x)
 409 {
 410     return x->data;
 411 }
 412 #endif
 413
 414 char *ossl_sk_ASN1_UTF8STRING2text(STACK_OF(ASN1_UTF8STRING) *text,
 415                                    const char *sep,
 416                                    size_t max_len /* excluding NUL terminator */)
 417 {
 418     int i;
 419     ASN1_UTF8STRING *current;
 420     size_t length = 0, sep_len;
 421     char *result = NULL;
 422     char *p;
 423
 424     if (!ossl_assert(sep != NULL))
 425         return NULL;
 426     sep_len = strlen(sep);
 427
 428     for (i = 0; i < sk_ASN1_UTF8STRING_num(text); ++i) {
 429         current = sk_ASN1_UTF8STRING_value(text, i);
 430         if (i > 0)
 431             length += sep_len;
 432         length += ASN1_STRING_length(current);
 433         if (length > max_len)
 434             return NULL;
 435     }
 436     if ((result = OPENSSL_malloc(length + 1)) == NULL)
 437         return NULL;
 438
 439     for (i = 0, p = result; i < sk_ASN1_UTF8STRING_num(text); ++i) {
 440         current = sk_ASN1_UTF8STRING_value(text, i);
 441         length = ASN1_STRING_length(current);
 442         if (i > 0 && sep_len > 0) {
 443             strncpy(p, sep, sep_len + 1);
 444             p += sep_len;
 445         }
 446         strncpy(p, (const char *)ASN1_STRING_get0_data(current), length);
 447         p += length;
 448     }
 449     *p = '\0';
 450
 451     return result;
 452 }