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Current File : //usr/src/crypto/heimdal/lib/asn1/der_get.c |
/* * Copyright (c) 1997 - 2007 Kungliga Tekniska Högskolan * (Royal Institute of Technology, Stockholm, Sweden). * All rights reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * * 3. Neither the name of the Institute nor the names of its contributors * may be used to endorse or promote products derived from this software * without specific prior written permission. * * THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``AS IS'' AND * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE * ARE DISCLAIMED. IN NO EVENT SHALL THE INSTITUTE OR CONTRIBUTORS BE LIABLE * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF * SUCH DAMAGE. */ #include "der_locl.h" RCSID("$Id: der_get.c 21369 2007-06-27 10:14:39Z lha $"); #include <version.h> /* * All decoding functions take a pointer `p' to first position in * which to read, from the left, `len' which means the maximum number * of characters we are able to read, `ret' were the value will be * returned and `size' where the number of used bytes is stored. * Either 0 or an error code is returned. */ int der_get_unsigned (const unsigned char *p, size_t len, unsigned *ret, size_t *size) { unsigned val = 0; size_t oldlen = len; if (len == sizeof(unsigned) + 1 && p[0] == 0) ; else if (len > sizeof(unsigned)) return ASN1_OVERRUN; while (len--) val = val * 256 + *p++; *ret = val; if(size) *size = oldlen; return 0; } int der_get_integer (const unsigned char *p, size_t len, int *ret, size_t *size) { int val = 0; size_t oldlen = len; if (len > sizeof(int)) return ASN1_OVERRUN; if (len > 0) { val = (signed char)*p++; while (--len) val = val * 256 + *p++; } *ret = val; if(size) *size = oldlen; return 0; } int der_get_length (const unsigned char *p, size_t len, size_t *val, size_t *size) { size_t v; if (len <= 0) return ASN1_OVERRUN; --len; v = *p++; if (v < 128) { *val = v; if(size) *size = 1; } else { int e; size_t l; unsigned tmp; if(v == 0x80){ *val = ASN1_INDEFINITE; if(size) *size = 1; return 0; } v &= 0x7F; if (len < v) return ASN1_OVERRUN; e = der_get_unsigned (p, v, &tmp, &l); if(e) return e; *val = tmp; if(size) *size = l + 1; } return 0; } int der_get_boolean(const unsigned char *p, size_t len, int *data, size_t *size) { if(len < 1) return ASN1_OVERRUN; if(*p != 0) *data = 1; else *data = 0; *size = 1; return 0; } int der_get_general_string (const unsigned char *p, size_t len, heim_general_string *str, size_t *size) { const unsigned char *p1; char *s; p1 = memchr(p, 0, len); if (p1 != NULL) { /* * Allow trailing NULs. We allow this since MIT Kerberos sends * an strings in the NEED_PREAUTH case that includes a * trailing NUL. */ while (p1 - p < len && *p1 == '\0') p1++; if (p1 - p != len) return ASN1_BAD_CHARACTER; } if (len > len + 1) return ASN1_BAD_LENGTH; s = malloc (len + 1); if (s == NULL) return ENOMEM; memcpy (s, p, len); s[len] = '\0'; *str = s; if(size) *size = len; return 0; } int der_get_utf8string (const unsigned char *p, size_t len, heim_utf8_string *str, size_t *size) { return der_get_general_string(p, len, str, size); } int der_get_printable_string (const unsigned char *p, size_t len, heim_printable_string *str, size_t *size) { return der_get_general_string(p, len, str, size); } int der_get_ia5_string (const unsigned char *p, size_t len, heim_ia5_string *str, size_t *size) { return der_get_general_string(p, len, str, size); } int der_get_bmp_string (const unsigned char *p, size_t len, heim_bmp_string *data, size_t *size) { size_t i; if (len & 1) return ASN1_BAD_FORMAT; data->length = len / 2; if (data->length > UINT_MAX/sizeof(data->data[0])) return ERANGE; data->data = malloc(data->length * sizeof(data->data[0])); if (data->data == NULL && data->length != 0) return ENOMEM; for (i = 0; i < data->length; i++) { data->data[i] = (p[0] << 8) | p[1]; p += 2; } if (size) *size = len; return 0; } int der_get_universal_string (const unsigned char *p, size_t len, heim_universal_string *data, size_t *size) { size_t i; if (len & 3) return ASN1_BAD_FORMAT; data->length = len / 4; if (data->length > UINT_MAX/sizeof(data->data[0])) return ERANGE; data->data = malloc(data->length * sizeof(data->data[0])); if (data->data == NULL && data->length != 0) return ENOMEM; for (i = 0; i < data->length; i++) { data->data[i] = (p[0] << 24) | (p[1] << 16) | (p[2] << 8) | p[3]; p += 4; } if (size) *size = len; return 0; } int der_get_visible_string (const unsigned char *p, size_t len, heim_visible_string *str, size_t *size) { return der_get_general_string(p, len, str, size); } int der_get_octet_string (const unsigned char *p, size_t len, heim_octet_string *data, size_t *size) { data->length = len; data->data = malloc(len); if (data->data == NULL && data->length != 0) return ENOMEM; memcpy (data->data, p, len); if(size) *size = len; return 0; } int der_get_heim_integer (const unsigned char *p, size_t len, heim_integer *data, size_t *size) { data->length = 0; data->negative = 0; data->data = NULL; if (len == 0) { if (size) *size = 0; return 0; } if (p[0] & 0x80) { unsigned char *q; int carry = 1; data->negative = 1; data->length = len; if (p[0] == 0xff) { p++; data->length--; } data->data = malloc(data->length); if (data->data == NULL) { data->length = 0; if (size) *size = 0; return ENOMEM; } q = &((unsigned char*)data->data)[data->length - 1]; p += data->length - 1; while (q >= (unsigned char*)data->data) { *q = *p ^ 0xff; if (carry) carry = !++*q; p--; q--; } } else { data->negative = 0; data->length = len; if (p[0] == 0) { p++; data->length--; } data->data = malloc(data->length); if (data->data == NULL && data->length != 0) { data->length = 0; if (size) *size = 0; return ENOMEM; } memcpy(data->data, p, data->length); } if (size) *size = len; return 0; } static int generalizedtime2time (const char *s, time_t *t) { struct tm tm; memset(&tm, 0, sizeof(tm)); if (sscanf (s, "%04d%02d%02d%02d%02d%02dZ", &tm.tm_year, &tm.tm_mon, &tm.tm_mday, &tm.tm_hour, &tm.tm_min, &tm.tm_sec) != 6) { if (sscanf (s, "%02d%02d%02d%02d%02d%02dZ", &tm.tm_year, &tm.tm_mon, &tm.tm_mday, &tm.tm_hour, &tm.tm_min, &tm.tm_sec) != 6) return ASN1_BAD_TIMEFORMAT; if (tm.tm_year < 50) tm.tm_year += 2000; else tm.tm_year += 1900; } tm.tm_year -= 1900; tm.tm_mon -= 1; *t = _der_timegm (&tm); return 0; } static int der_get_time (const unsigned char *p, size_t len, time_t *data, size_t *size) { char *times; int e; if (len > len + 1 || len == 0) return ASN1_BAD_LENGTH; times = malloc(len + 1); if (times == NULL) return ENOMEM; memcpy(times, p, len); times[len] = '\0'; e = generalizedtime2time(times, data); free (times); if(size) *size = len; return e; } int der_get_generalized_time (const unsigned char *p, size_t len, time_t *data, size_t *size) { return der_get_time(p, len, data, size); } int der_get_utctime (const unsigned char *p, size_t len, time_t *data, size_t *size) { return der_get_time(p, len, data, size); } int der_get_oid (const unsigned char *p, size_t len, heim_oid *data, size_t *size) { size_t n; size_t oldlen = len; if (len < 1) return ASN1_OVERRUN; if (len > len + 1) return ASN1_BAD_LENGTH; if (len + 1 > UINT_MAX/sizeof(data->components[0])) return ERANGE; data->components = malloc((len + 1) * sizeof(data->components[0])); if (data->components == NULL) return ENOMEM; data->components[0] = (*p) / 40; data->components[1] = (*p) % 40; --len; ++p; for (n = 2; len > 0; ++n) { unsigned u = 0, u1; do { --len; u1 = u * 128 + (*p++ % 128); /* check that we don't overflow the element */ if (u1 < u) { der_free_oid(data); return ASN1_OVERRUN; } u = u1; } while (len > 0 && p[-1] & 0x80); data->components[n] = u; } if (n > 2 && p[-1] & 0x80) { der_free_oid (data); return ASN1_OVERRUN; } data->length = n; if (size) *size = oldlen; return 0; } int der_get_tag (const unsigned char *p, size_t len, Der_class *class, Der_type *type, unsigned int *tag, size_t *size) { size_t ret = 0; if (len < 1) return ASN1_OVERRUN; *class = (Der_class)(((*p) >> 6) & 0x03); *type = (Der_type)(((*p) >> 5) & 0x01); *tag = (*p) & 0x1f; p++; len--; ret++; if(*tag == 0x1f) { unsigned int continuation; unsigned int tag1; *tag = 0; do { if(len < 1) return ASN1_OVERRUN; continuation = *p & 128; tag1 = *tag * 128 + (*p % 128); /* check that we don't overflow the tag */ if (tag1 < *tag) return ASN1_OVERFLOW; *tag = tag1; p++; len--; ret++; } while(continuation); } if(size) *size = ret; return 0; } int der_match_tag (const unsigned char *p, size_t len, Der_class class, Der_type type, unsigned int tag, size_t *size) { size_t l; Der_class thisclass; Der_type thistype; unsigned int thistag; int e; e = der_get_tag (p, len, &thisclass, &thistype, &thistag, &l); if (e) return e; if (class != thisclass || type != thistype) return ASN1_BAD_ID; if(tag > thistag) return ASN1_MISPLACED_FIELD; if(tag < thistag) return ASN1_MISSING_FIELD; if(size) *size = l; return 0; } int der_match_tag_and_length (const unsigned char *p, size_t len, Der_class class, Der_type type, unsigned int tag, size_t *length_ret, size_t *size) { size_t l, ret = 0; int e; e = der_match_tag (p, len, class, type, tag, &l); if (e) return e; p += l; len -= l; ret += l; e = der_get_length (p, len, length_ret, &l); if (e) return e; p += l; len -= l; ret += l; if(size) *size = ret; return 0; } /* * Old versions of DCE was based on a very early beta of the MIT code, * which used MAVROS for ASN.1 encoding. MAVROS had the interesting * feature that it encoded data in the forward direction, which has * it's problems, since you have no idea how long the data will be * until after you're done. MAVROS solved this by reserving one byte * for length, and later, if the actual length was longer, it reverted * to indefinite, BER style, lengths. The version of MAVROS used by * the DCE people could apparently generate correct X.509 DER encodings, and * did this by making space for the length after encoding, but * unfortunately this feature wasn't used with Kerberos. */ int _heim_fix_dce(size_t reallen, size_t *len) { if(reallen == ASN1_INDEFINITE) return 1; if(*len < reallen) return -1; *len = reallen; return 0; } int der_get_bit_string (const unsigned char *p, size_t len, heim_bit_string *data, size_t *size) { if (len < 1) return ASN1_OVERRUN; if (p[0] > 7) return ASN1_BAD_FORMAT; if (len - 1 == 0 && p[0] != 0) return ASN1_BAD_FORMAT; /* check if any of the three upper bits are set * any of them will cause a interger overrun */ if ((len - 1) >> (sizeof(len) * 8 - 3)) return ASN1_OVERRUN; data->length = (len - 1) * 8; data->data = malloc(len - 1); if (data->data == NULL && (len - 1) != 0) return ENOMEM; memcpy (data->data, p + 1, len - 1); data->length -= p[0]; if(size) *size = len; return 0; }