/src/libressl/crypto/x509/x509_utl.c

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/* $OpenBSD: x509_utl.c,v 1.3 2022/05/20 07:58:54 tb Exp $ */
/* Written by Dr Stephen N Henson (steve@openssl.org) for the OpenSSL
 * project.
 */
/* ====================================================================
 * Copyright (c) 1999-2003 The OpenSSL Project.  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. All advertising materials mentioning features or use of this
 *    software must display the following acknowledgment:
 *    "This product includes software developed by the OpenSSL Project
 *    for use in the OpenSSL Toolkit. (http://www.OpenSSL.org/)"
 *
 * 4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to
 *    endorse or promote products derived from this software without
 *    prior written permission. For written permission, please contact
 *    licensing@OpenSSL.org.
 *
 * 5. Products derived from this software may not be called "OpenSSL"
 *    nor may "OpenSSL" appear in their names without prior written
 *    permission of the OpenSSL Project.
 *
 * 6. Redistributions of any form whatsoever must retain the following
 *    acknowledgment:
 *    "This product includes software developed by the OpenSSL Project
 *    for use in the OpenSSL Toolkit (http://www.OpenSSL.org/)"
 *
 * THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY
 * EXPRESSED 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 OpenSSL PROJECT OR
 * ITS 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.
 * ====================================================================
 *
 * This product includes cryptographic software written by Eric Young
 * (eay@cryptsoft.com).  This product includes software written by Tim
 * Hudson (tjh@cryptsoft.com).
 *
 */
/* X509 v3 extension utilities */

#include <ctype.h>
#include <stdio.h>
#include <string.h>

#include <openssl/bn.h>
#include <openssl/conf.h>
#include <openssl/err.h>
#include <openssl/x509v3.h>

char *bn_to_string(const BIGNUM *bn);
static char *strip_spaces(char *name);
static int sk_strcmp(const char * const *a, const char * const *b);
static STACK_OF(OPENSSL_STRING) *get_email(X509_NAME *name,
    GENERAL_NAMES *gens);
static void str_free(OPENSSL_STRING str);
static int append_ia5(STACK_OF(OPENSSL_STRING) **sk, ASN1_IA5STRING *email);

static int ipv4_from_asc(unsigned char *v4, const char *in);
static int ipv6_from_asc(unsigned char *v6, const char *in);
static int ipv6_cb(const char *elem, int len, void *usr);
static int ipv6_hex(unsigned char *out, const char *in, int inlen);

/* Add a CONF_VALUE name-value pair to stack. */
int
X509V3_add_value(const char *name, const char *value,
    STACK_OF(CONF_VALUE) **extlist)
{
  CONF_VALUE *vtmp = NULL;
  STACK_OF(CONF_VALUE) *free_exts = NULL;

  if ((vtmp = calloc(1, sizeof(CONF_VALUE))) == NULL)
    goto err;
  if (name != NULL) {
    if ((vtmp->name = strdup(name)) == NULL)
      goto err;
  }
  if (value != NULL) {
    if ((vtmp->value = strdup(value)) == NULL)
      goto err;
  }

  if (*extlist == NULL) {
    if ((free_exts = *extlist = sk_CONF_VALUE_new_null()) == NULL)
      goto err;
  }

  if (!sk_CONF_VALUE_push(*extlist, vtmp))
    goto err;

  return 1;

 err:
  X509V3error(ERR_R_MALLOC_FAILURE);
  X509V3_conf_free(vtmp);
  if (free_exts != NULL) {
    sk_CONF_VALUE_free(*extlist);
    *extlist = NULL;
  }
  return 0;
}

int
X509V3_add_value_uchar(const char *name, const unsigned char *value,
    STACK_OF(CONF_VALUE) **extlist)
{
  return X509V3_add_value(name, (const char *)value, extlist);
}

/* Free function for STACK_OF(CONF_VALUE) */

void
X509V3_conf_free(CONF_VALUE *conf)
{
  if (!conf)
    return;
  free(conf->name);
  free(conf->value);
  free(conf->section);
  free(conf);
}

int
X509V3_add_value_bool(const char *name, int asn1_bool,
    STACK_OF(CONF_VALUE) **extlist)
{
  if (asn1_bool)
    return X509V3_add_value(name, "TRUE", extlist);
  return X509V3_add_value(name, "FALSE", extlist);
}

int
X509V3_add_value_bool_nf(const char *name, int asn1_bool,
    STACK_OF(CONF_VALUE) **extlist)
{
  if (asn1_bool)
    return X509V3_add_value(name, "TRUE", extlist);
  return 1;
}

char *
bn_to_string(const BIGNUM *bn)
{
  const char *sign = "";
  char *bnstr, *hex;
  char *ret = NULL;

  /* Only display small numbers in decimal, as conversion is quadratic. */
  if (BN_num_bits(bn) < 128)
    return BN_bn2dec(bn);

  if ((hex = bnstr = BN_bn2hex(bn)) == NULL)
    goto err;

  if (BN_is_negative(bn)) {
    sign = "-";
    hex++;
  }

  if (asprintf(&ret, "%s0x%s", sign, hex) == -1)
    ret = NULL;

 err:
  free(bnstr);
  return ret;
}

char *
i2s_ASN1_ENUMERATED(X509V3_EXT_METHOD *method, const ASN1_ENUMERATED *a)
{
  BIGNUM *bntmp;
  char *strtmp = NULL;

  if (a == NULL)
    return NULL;
  if ((bntmp = ASN1_ENUMERATED_to_BN(a, NULL)) == NULL ||
      (strtmp = bn_to_string(bntmp)) == NULL)
    X509V3error(ERR_R_MALLOC_FAILURE);
  BN_free(bntmp);
  return strtmp;
}

char *
i2s_ASN1_INTEGER(X509V3_EXT_METHOD *method, const ASN1_INTEGER *a)
{
  BIGNUM *bntmp;
  char *strtmp = NULL;

  if (a == NULL)
    return NULL;
  if ((bntmp = ASN1_INTEGER_to_BN(a, NULL)) == NULL ||
      (strtmp = bn_to_string(bntmp)) == NULL)
    X509V3error(ERR_R_MALLOC_FAILURE);
  BN_free(bntmp);
  return strtmp;
}

ASN1_INTEGER *
s2i_ASN1_INTEGER(X509V3_EXT_METHOD *method, const char *value)
{
  BIGNUM *bn = NULL;
  ASN1_INTEGER *aint;
  int isneg, ishex;
  int ret;

  if (!value) {
    X509V3error(X509V3_R_INVALID_NULL_VALUE);
    return 0;
  }
  bn = BN_new();
  if (value[0] == '-') {
    value++;
    isneg = 1;
  } else
    isneg = 0;

  if (value[0] == '0' && ((value[1] == 'x') || (value[1] == 'X'))) {
    value += 2;
    ishex = 1;
  } else
    ishex = 0;

  if (ishex)
    ret = BN_hex2bn(&bn, value);
  else
    ret = BN_dec2bn(&bn, value);

  if (!ret || value[ret]) {
    BN_free(bn);
    X509V3error(X509V3_R_BN_DEC2BN_ERROR);
    return 0;
  }

  if (isneg && BN_is_zero(bn))
    isneg = 0;

  aint = BN_to_ASN1_INTEGER(bn, NULL);
  BN_free(bn);
  if (!aint) {
    X509V3error(X509V3_R_BN_TO_ASN1_INTEGER_ERROR);
    return 0;
  }
  if (isneg)
    aint->type |= V_ASN1_NEG;
  return aint;
}

int
X509V3_add_value_int(const char *name, const ASN1_INTEGER *aint,
    STACK_OF(CONF_VALUE) **extlist)
{
  char *strtmp;
  int ret;

  if (!aint)
    return 1;
  if (!(strtmp = i2s_ASN1_INTEGER(NULL, aint)))
    return 0;
  ret = X509V3_add_value(name, strtmp, extlist);
  free(strtmp);
  return ret;
}

int
X509V3_get_value_bool(const CONF_VALUE *value, int *asn1_bool)
{
  char *btmp;

  if (!(btmp = value->value))
    goto err;
  if (!strcmp(btmp, "TRUE") || !strcmp(btmp, "true") ||
      !strcmp(btmp, "Y") || !strcmp(btmp, "y") ||
      !strcmp(btmp, "YES") || !strcmp(btmp, "yes")) {
    *asn1_bool = 0xff;
    return 1;
  } else if (!strcmp(btmp, "FALSE") || !strcmp(btmp, "false") ||
      !strcmp(btmp, "N") || !strcmp(btmp, "n") ||
      !strcmp(btmp, "NO") || !strcmp(btmp, "no")) {
    *asn1_bool = 0;
    return 1;
  }

 err:
  X509V3error(X509V3_R_INVALID_BOOLEAN_STRING);
  X509V3_conf_err(value);
  return 0;
}

int
X509V3_get_value_int(const CONF_VALUE *value, ASN1_INTEGER **aint)
{
  ASN1_INTEGER *itmp;

  if (!(itmp = s2i_ASN1_INTEGER(NULL, value->value))) {
    X509V3_conf_err(value);
    return 0;
  }
  *aint = itmp;
  return 1;
}

#define HDR_NAME  1
#define HDR_VALUE 2

/*#define DEBUG*/

STACK_OF(CONF_VALUE) *
X509V3_parse_list(const char *line)
{
  char *p, *q, c;
  char *ntmp, *vtmp;
  STACK_OF(CONF_VALUE) *values = NULL;
  char *linebuf;
  int state;

  /* We are going to modify the line so copy it first */
  if ((linebuf = strdup(line)) == NULL) {
    X509V3error(ERR_R_MALLOC_FAILURE);
    goto err;
  }
  state = HDR_NAME;
  ntmp = NULL;

  /* Go through all characters */
  for (p = linebuf, q = linebuf; (c = *p) && (c != '\r') &&
      (c != '\n'); p++) {

    switch (state) {
    case HDR_NAME:
      if (c == ':') {
        state = HDR_VALUE;
        *p = 0;
        ntmp = strip_spaces(q);
        if (!ntmp) {
          X509V3error(X509V3_R_INVALID_NULL_NAME);
          goto err;
        }
        q = p + 1;
      } else if (c == ',') {
        *p = 0;
        ntmp = strip_spaces(q);
        q = p + 1;
        if (!ntmp) {
          X509V3error(X509V3_R_INVALID_NULL_NAME);
          goto err;
        }
        X509V3_add_value(ntmp, NULL, &values);
      }
      break;

    case HDR_VALUE:
      if (c == ',') {
        state = HDR_NAME;
        *p = 0;
        vtmp = strip_spaces(q);
        if (!vtmp) {
          X509V3error(X509V3_R_INVALID_NULL_VALUE);
          goto err;
        }
        X509V3_add_value(ntmp, vtmp, &values);
        ntmp = NULL;
        q = p + 1;
      }

    }
  }

  if (state == HDR_VALUE) {
    vtmp = strip_spaces(q);
    if (!vtmp) {
      X509V3error(X509V3_R_INVALID_NULL_VALUE);
      goto err;
    }
    X509V3_add_value(ntmp, vtmp, &values);
  } else {
    ntmp = strip_spaces(q);
    if (!ntmp) {
      X509V3error(X509V3_R_INVALID_NULL_NAME);
      goto err;
    }
    X509V3_add_value(ntmp, NULL, &values);
  }
  free(linebuf);
  return values;

 err:
  free(linebuf);
  sk_CONF_VALUE_pop_free(values, X509V3_conf_free);
  return NULL;

}

/* Delete leading and trailing spaces from a string */
static char *
strip_spaces(char *name)
{
  char *p, *q;

  /* Skip over leading spaces */
  p = name;
  while (*p && isspace((unsigned char)*p))
    p++;
  if (!*p)
    return NULL;
  q = p + strlen(p) - 1;
  while ((q != p) && isspace((unsigned char)*q))
    q--;
  if (p != q)
    q[1] = 0;
  if (!*p)
    return NULL;
  return p;
}

/* hex string utilities */

/* Given a buffer of length 'len' return a malloc'ed string with its
 * hex representation
 */
char *
hex_to_string(const unsigned char *buffer, long len)
{
  char *tmp, *q;
  const unsigned char *p;
  int i;
  static const char hexdig[] = "0123456789ABCDEF";

  if (!buffer || !len)
    return NULL;
  if (!(tmp = malloc(len * 3 + 1))) {
    X509V3error(ERR_R_MALLOC_FAILURE);
    return NULL;
  }
  q = tmp;
  for (i = 0, p = buffer; i < len; i++, p++) {
    *q++ = hexdig[(*p >> 4) & 0xf];
    *q++ = hexdig[*p & 0xf];
    *q++ = ':';
  }
  q[-1] = 0;
  return tmp;
}

/* Give a string of hex digits convert to
 * a buffer
 */

unsigned char *
string_to_hex(const char *str, long *len)
{
  unsigned char *hexbuf, *q;
  unsigned char ch, cl, *p;
  if (!str) {
    X509V3error(X509V3_R_INVALID_NULL_ARGUMENT);
    return NULL;
  }
  if (!(hexbuf = malloc(strlen(str) >> 1)))
    goto err;
  for (p = (unsigned char *)str, q = hexbuf; *p; ) {
    ch = *p++;
    if (ch == ':')
      continue;
    cl = *p++;
    if (!cl) {
      X509V3error(X509V3_R_ODD_NUMBER_OF_DIGITS);
      free(hexbuf);
      return NULL;
    }
    ch = tolower(ch);
    cl = tolower(cl);

    if ((ch >= '0') && (ch <= '9'))
      ch -= '0';
    else if ((ch >= 'a') && (ch <= 'f'))
      ch -= 'a' - 10;
    else
      goto badhex;

    if ((cl >= '0') && (cl <= '9'))
      cl -= '0';
    else if ((cl >= 'a') && (cl <= 'f'))
      cl -= 'a' - 10;
    else
      goto badhex;

    *q++ = (ch << 4) | cl;
  }

  if (len)
    *len = q - hexbuf;

  return hexbuf;

 err:
  free(hexbuf);
  X509V3error(ERR_R_MALLOC_FAILURE);
  return NULL;

 badhex:
  free(hexbuf);
  X509V3error(X509V3_R_ILLEGAL_HEX_DIGIT);
  return NULL;
}

/* V2I name comparison function: returns zero if 'name' matches
 * cmp or cmp.*
 */

int
name_cmp(const char *name, const char *cmp)
{
  int len, ret;
  char c;

  len = strlen(cmp);
  if ((ret = strncmp(name, cmp, len)))
    return ret;
  c = name[len];
  if (!c || (c=='.'))
    return 0;
  return 1;
}

static int
sk_strcmp(const char * const *a, const char * const *b)
{
  return strcmp(*a, *b);
}

STACK_OF(OPENSSL_STRING) *
X509_get1_email(X509 *x)
{
  GENERAL_NAMES *gens;
  STACK_OF(OPENSSL_STRING) *ret;

  gens = X509_get_ext_d2i(x, NID_subject_alt_name, NULL, NULL);
  ret = get_email(X509_get_subject_name(x), gens);
  sk_GENERAL_NAME_pop_free(gens, GENERAL_NAME_free);
  return ret;
}

STACK_OF(OPENSSL_STRING) *
X509_get1_ocsp(X509 *x)
{
  AUTHORITY_INFO_ACCESS *info;
  STACK_OF(OPENSSL_STRING) *ret = NULL;
  int i;

  info = X509_get_ext_d2i(x, NID_info_access, NULL, NULL);
  if (!info)
    return NULL;
  for (i = 0; i < sk_ACCESS_DESCRIPTION_num(info); i++) {
    ACCESS_DESCRIPTION *ad = sk_ACCESS_DESCRIPTION_value(info, i);
    if (OBJ_obj2nid(ad->method) == NID_ad_OCSP) {
      if (ad->location->type == GEN_URI) {
        if (!append_ia5(&ret,
            ad->location->d.uniformResourceIdentifier))
          break;
      }
    }
  }
  AUTHORITY_INFO_ACCESS_free(info);
  return ret;
}

STACK_OF(OPENSSL_STRING) *
X509_REQ_get1_email(X509_REQ *x)
{
  GENERAL_NAMES *gens;
  STACK_OF(X509_EXTENSION) *exts;
  STACK_OF(OPENSSL_STRING) *ret;

  exts = X509_REQ_get_extensions(x);
  gens = X509V3_get_d2i(exts, NID_subject_alt_name, NULL, NULL);
  ret = get_email(X509_REQ_get_subject_name(x), gens);
  sk_GENERAL_NAME_pop_free(gens, GENERAL_NAME_free);
  sk_X509_EXTENSION_pop_free(exts, X509_EXTENSION_free);
  return ret;
}


static STACK_OF(OPENSSL_STRING) *
get_email(X509_NAME *name, GENERAL_NAMES *gens)
{
  STACK_OF(OPENSSL_STRING) *ret = NULL;
  X509_NAME_ENTRY *ne;
  ASN1_IA5STRING *email;
  GENERAL_NAME *gen;
  int i;

  /* Now add any email address(es) to STACK */
  i = -1;

  /* First supplied X509_NAME */
  while ((i = X509_NAME_get_index_by_NID(name,
      NID_pkcs9_emailAddress, i)) >= 0) {
    ne = X509_NAME_get_entry(name, i);
    email = X509_NAME_ENTRY_get_data(ne);
    if (!append_ia5(&ret, email))
      return NULL;
  }
  for (i = 0; i < sk_GENERAL_NAME_num(gens); i++) {
    gen = sk_GENERAL_NAME_value(gens, i);
    if (gen->type != GEN_EMAIL)
      continue;
    if (!append_ia5(&ret, gen->d.ia5))
      return NULL;
  }
  return ret;
}

static void
str_free(OPENSSL_STRING str)
{
  free(str);
}

static int
append_ia5(STACK_OF(OPENSSL_STRING) **sk, ASN1_IA5STRING *email)
{
  char *emtmp;

  /* First some sanity checks */
  if (email->type != V_ASN1_IA5STRING)
    return 1;
  if (!email->data || !email->length)
    return 1;
  if (!*sk)
    *sk = sk_OPENSSL_STRING_new(sk_strcmp);
  if (!*sk)
    return 0;
  /* Don't add duplicates */
  if (sk_OPENSSL_STRING_find(*sk, (char *)email->data) != -1)
    return 1;
  emtmp = strdup((char *)email->data);
  if (!emtmp || !sk_OPENSSL_STRING_push(*sk, emtmp)) {
    X509_email_free(*sk);
    *sk = NULL;
    return 0;
  }
  return 1;
}

void
X509_email_free(STACK_OF(OPENSSL_STRING) *sk)
{
  sk_OPENSSL_STRING_pop_free(sk, str_free);
}

typedef int (*equal_fn)(const unsigned char *pattern, size_t pattern_len,
    const unsigned char *subject, size_t subject_len, unsigned int flags);

/* Skip pattern prefix to match "wildcard" subject */
static void
skip_prefix(const unsigned char **p, size_t *plen, const unsigned char *subject,
    size_t subject_len, unsigned int flags)
{
  const unsigned char *pattern = *p;
  size_t pattern_len = *plen;

  /*
   * If subject starts with a leading '.' followed by more octets, and
   * pattern is longer, compare just an equal-length suffix with the
   * full subject (starting at the '.'), provided the prefix contains
   * no NULs.
   */
  if ((flags & _X509_CHECK_FLAG_DOT_SUBDOMAINS) == 0)
    return;

  while (pattern_len > subject_len && *pattern) {
    if ((flags & X509_CHECK_FLAG_SINGLE_LABEL_SUBDOMAINS) &&
        *pattern == '.')
      break;
    ++pattern;
    --pattern_len;
  }

  /* Skip if entire prefix acceptable */
  if (pattern_len == subject_len) {
    *p = pattern;
    *plen = pattern_len;
  }
}

/*
 * Open/BoringSSL uses memcmp for "equal_case" while their
 * "equal_nocase" function is a hand-rolled strncasecmp that does not
 * allow \0 in the pattern. Since an embedded \0 is likely a sign of
 * problems, we simply don't allow it in either case, and then we use
 * standard libc funcitons.
 */

/* Compare using strncasecmp */
static int
equal_nocase(const unsigned char *pattern, size_t pattern_len,
    const unsigned char *subject, size_t subject_len, unsigned int flags)
{
  if (memchr(pattern, '\0', pattern_len) != NULL)
    return 0;
  if (memchr(subject, '\0', subject_len) != NULL)
    return 0;
  skip_prefix(&pattern, &pattern_len, subject, subject_len, flags);
  if (pattern_len != subject_len)
    return 0;
  return (strncasecmp(pattern, subject, pattern_len) == 0);
}

/* Compare using strncmp. */
static int
equal_case(const unsigned char *pattern, size_t pattern_len,
    const unsigned char *subject, size_t subject_len, unsigned int flags)
{
  if (memchr(pattern, 0, pattern_len) != NULL)
    return 0;
  if (memchr(subject, 0, subject_len) != NULL)
    return 0;
  skip_prefix(&pattern, &pattern_len, subject, subject_len, flags);
  if (pattern_len != subject_len)
    return 0;
  return (strncmp(pattern, subject, pattern_len) == 0);
}

/*
 * RFC 5280, section 7.5, requires that only the domain is compared in a
 * case-insensitive manner.
 */
static int
equal_email(const unsigned char *a, size_t a_len, const unsigned char *b,
    size_t b_len, unsigned int unused_flags)
{
  size_t pos = a_len;
  if (a_len != b_len)
    return 0;
  /*
   * We search backwards for the '@' character, so that we do not have to
   * deal with quoted local-parts.  The domain part is compared in a
   * case-insensitive manner.
   */
  while (pos > 0) {
    pos--;
    if (a[pos] == '@' || b[pos] == '@') {
      if (!equal_nocase(a + pos, a_len - pos, b + pos,
          a_len - pos, 0))
        return 0;
      break;
    }
  }
  if (pos == 0)
    pos = a_len;
  return equal_case(a, pos, b, pos, 0);
}

/*
 * Compare the prefix and suffix with the subject, and check that the
 * characters in-between are valid.
 */
static int
wildcard_match(const unsigned char *prefix, size_t prefix_len,
    const unsigned char *suffix, size_t suffix_len,
    const unsigned char *subject, size_t subject_len, unsigned int flags)
{
  const unsigned char *wildcard_start;
  const unsigned char *wildcard_end;
  const unsigned char *p;
  int allow_multi = 0;
  int allow_idna = 0;

  if (subject_len < prefix_len + suffix_len)
    return 0;
  if (!equal_nocase(prefix, prefix_len, subject, prefix_len, flags))
    return 0;
  wildcard_start = subject + prefix_len;
  wildcard_end = subject + (subject_len - suffix_len);
  if (!equal_nocase(wildcard_end, suffix_len, suffix, suffix_len, flags))
    return 0;
  /*
   * If the wildcard makes up the entire first label, it must match at
   * least one character.
   */
  if (prefix_len == 0 && *suffix == '.') {
    if (wildcard_start == wildcard_end)
      return 0;
    allow_idna = 1;
    if (flags & X509_CHECK_FLAG_MULTI_LABEL_WILDCARDS)
      allow_multi = 1;
  }
  /* IDNA labels cannot match partial wildcards */
  if (!allow_idna &&
      subject_len >= 4
      && strncasecmp((char *)subject, "xn--", 4) == 0)
    return 0;
  /* The wildcard may match a literal '*' */
  if (wildcard_end == wildcard_start + 1 && *wildcard_start == '*')
    return 1;
  /*
   * Check that the part matched by the wildcard contains only
   * permitted characters and only matches a single label unless
   * allow_multi is set.
   */
  for (p = wildcard_start; p != wildcard_end; ++p)
    if (!(('0' <= *p && *p <= '9') || ('A' <= *p && *p <= 'Z') ||
        ('a' <= *p && *p <= 'z') || *p == '-' ||
        (allow_multi && *p == '.')))
      return 0;
  return 1;
}

#define LABEL_START     (1 << 0)
#define LABEL_END       (1 << 1)
#define LABEL_HYPHEN    (1 << 2)
#define LABEL_IDNA      (1 << 3)

static const unsigned char *
valid_star(const unsigned char *p, size_t len, unsigned int flags)
{
  const unsigned char *star = 0;
  size_t i;
  int state = LABEL_START;
  int dots = 0;
  for (i = 0; i < len; ++i) {
    /*
     * Locate first and only legal wildcard, either at the start
     * or end of a non-IDNA first and not final label.
     */
    if (p[i] == '*') {
      int atstart = (state & LABEL_START);
      int atend = (i == len - 1 || p[i + 1] == '.');
      /*
       * At most one wildcard per pattern.
       * No wildcards in IDNA labels.
       * No wildcards after the first label.
       */
      if (star != NULL || (state & LABEL_IDNA) != 0 || dots)
        return NULL;
      /* Only full-label '*.example.com' wildcards? */
      if ((flags & X509_CHECK_FLAG_NO_PARTIAL_WILDCARDS)
          && (!atstart || !atend))
        return NULL;
      /* No 'foo*bar' wildcards */
      if (!atstart && !atend)
        return NULL;
      star = &p[i];
      state &= ~LABEL_START;
    } else if ((state & LABEL_START) != 0) {
      /*
       * At the start of a label, skip any "xn--" and
       * remain in the LABEL_START state, but set the
       * IDNA label state
       */
      if ((state & LABEL_IDNA) == 0 && len - i >= 4
          && strncasecmp((char *)&p[i], "xn--", 4) == 0) {
        i += 3;
        state |= LABEL_IDNA;
        continue;
      }
      /* Labels must start with a letter or digit */
      state &= ~LABEL_START;
      if (('a' <= p[i] && p[i] <= 'z')
          || ('A' <= p[i] && p[i] <= 'Z')
          || ('0' <= p[i] && p[i] <= '9'))
        continue;
      return NULL;
    } else if (('a' <= p[i] && p[i] <= 'z')
        || ('A' <= p[i] && p[i] <= 'Z')
        || ('0' <= p[i] && p[i] <= '9')) {
      state &= LABEL_IDNA;
      continue;
    } else if (p[i] == '.') {
      if (state & (LABEL_HYPHEN | LABEL_START))
        return NULL;
      state = LABEL_START;
      ++dots;
    } else if (p[i] == '-') {
      /* no domain/subdomain starts with '-' */
      if ((state & LABEL_START) != 0)
        return NULL;
      state |= LABEL_HYPHEN;
    } else
      return NULL;
  }

  /*
   * The final label must not end in a hyphen or ".", and
   * there must be at least two dots after the star.
   */
  if ((state & (LABEL_START | LABEL_HYPHEN)) != 0 || dots < 2)
    return NULL;
  return star;
}

/* Compare using wildcards. */
static int
equal_wildcard(const unsigned char *pattern, size_t pattern_len,
    const unsigned char *subject, size_t subject_len, unsigned int flags)
{
  const unsigned char *star = NULL;

  /*
   * Subject names starting with '.' can only match a wildcard pattern
   * via a subject sub-domain pattern suffix match.
   */
  if (!(subject_len > 1 && subject[0] == '.'))
    star = valid_star(pattern, pattern_len, flags);
  if (star == NULL)
    return equal_nocase(pattern, pattern_len,
        subject, subject_len, flags);
  return wildcard_match(pattern, star - pattern,
      star + 1, (pattern + pattern_len) - star - 1,
      subject, subject_len, flags);
}

/*
 * Compare an ASN1_STRING to a supplied string. If they match return 1. If
 * cmp_type > 0 only compare if string matches the type, otherwise convert it
 * to UTF8.
 */

static int
do_check_string(ASN1_STRING *a, int cmp_type, equal_fn equal,
    unsigned int flags, const char *b, size_t blen, char **peername)
{
  int rv = 0;

  if (!a->data || !a->length)
    return 0;
  if (cmp_type > 0) {
    if (cmp_type != a->type)
      return 0;
    if (cmp_type == V_ASN1_IA5STRING)
      rv = equal(a->data, a->length, (unsigned char *)b,
          blen, flags);
    else if (a->length == (int)blen && !memcmp(a->data, b, blen))
      rv = 1;
    if (rv > 0 && peername &&
        (*peername = strndup((char *)a->data, a->length)) == NULL)
      rv = -1;
  } else {
    int astrlen;
    unsigned char *astr = NULL;
    astrlen = ASN1_STRING_to_UTF8(&astr, a);
    if (astrlen < 0)
      return -1;
    rv = equal(astr, astrlen, (unsigned char *)b, blen, flags);
    if (rv > 0 && peername &&
        (*peername = strndup((char *)astr, astrlen)) == NULL)
      rv = -1;
    free(astr);
  }
  return rv;
}

static int
do_x509_check(X509 *x, const char *chk, size_t chklen, unsigned int flags,
    int check_type, char **peername)
{
  GENERAL_NAMES *gens = NULL;
  X509_NAME *name = NULL;
  size_t i;
  int j;
  int cnid = NID_undef;
  int alt_type;
  int san_present = 0;
  int rv = 0;
  equal_fn equal;

  /* See below, this flag is internal-only */
  flags &= ~_X509_CHECK_FLAG_DOT_SUBDOMAINS;
  if (check_type == GEN_EMAIL) {
    cnid = NID_pkcs9_emailAddress;
    alt_type = V_ASN1_IA5STRING;
    equal = equal_email;
  } else if (check_type == GEN_DNS) {
    if (!(flags & X509_CHECK_FLAG_NEVER_CHECK_SUBJECT))
      cnid = NID_commonName;
    /* Implicit client-side DNS sub-domain pattern */
    if (chklen > 1 && chk[0] == '.')
      flags |= _X509_CHECK_FLAG_DOT_SUBDOMAINS;
    alt_type = V_ASN1_IA5STRING;
    if (flags & X509_CHECK_FLAG_NO_WILDCARDS)
      equal = equal_nocase;
    else
      equal = equal_wildcard;
  } else {
    alt_type = V_ASN1_OCTET_STRING;
    equal = equal_case;
  }

  gens = X509_get_ext_d2i(x, NID_subject_alt_name, NULL, NULL);
  if (gens != NULL) {
    for (i = 0; i < sk_GENERAL_NAME_num(gens); i++) {
      GENERAL_NAME *gen;
      ASN1_STRING *cstr;
      gen = sk_GENERAL_NAME_value(gens, i);
      if (gen->type != check_type)
        continue;
      san_present = 1;
      if (check_type == GEN_EMAIL)
        cstr = gen->d.rfc822Name;
      else if (check_type == GEN_DNS)
        cstr = gen->d.dNSName;
      else
        cstr = gen->d.iPAddress;
      /* Positive on success, negative on error! */
      if ((rv = do_check_string(cstr, alt_type, equal, flags,
          chk, chklen, peername)) != 0)
        break;
    }
    GENERAL_NAMES_free(gens);
    if (rv != 0)
      return rv;
    if (cnid == NID_undef ||
        (san_present &&
        !(flags & X509_CHECK_FLAG_ALWAYS_CHECK_SUBJECT)))
      return 0;
  }

  /* We're done if CN-ID is not pertinent */
  if (cnid == NID_undef)
    return 0;

  j = -1;
  name = X509_get_subject_name(x);
  while ((j = X509_NAME_get_index_by_NID(name, cnid, j)) >= 0) {
    X509_NAME_ENTRY *ne;
    ASN1_STRING *str;
    if ((ne = X509_NAME_get_entry(name, j)) == NULL)
      return -1;
    if ((str = X509_NAME_ENTRY_get_data(ne)) == NULL)
      return -1;
    /* Positive on success, negative on error! */
    if ((rv = do_check_string(str, -1, equal, flags,
       chk, chklen, peername)) != 0)
      return rv;
  }
  return 0;
}

int
X509_check_host(X509 *x, const char *chk, size_t chklen, unsigned int flags,
    char **peername)
{
  if (chk == NULL)
    return -2;
  if (chklen == 0)
    chklen = strlen(chk);
  else if (memchr(chk, '\0', chklen))
    return -2;
  return do_x509_check(x, chk, chklen, flags, GEN_DNS, peername);
}

int
X509_check_email(X509 *x, const char *chk, size_t chklen, unsigned int flags)
{
  if (chk == NULL)
    return -2;
  if (chklen == 0)
    chklen = strlen(chk);
  else if (memchr(chk, '\0', chklen))
    return -2;
  return do_x509_check(x, chk, chklen, flags, GEN_EMAIL, NULL);
}

int
X509_check_ip(X509 *x, const unsigned char *chk, size_t chklen,
    unsigned int flags)
{
  if (chk == NULL)
    return -2;
  return do_x509_check(x, (char *)chk, chklen, flags, GEN_IPADD, NULL);
}

int
X509_check_ip_asc(X509 *x, const char *ipasc, unsigned int flags)
{
  unsigned char ipout[16];
  size_t iplen;

  if (ipasc == NULL)
    return -2;
  iplen = (size_t)a2i_ipadd(ipout, ipasc);
  if (iplen == 0)
    return -2;
  return do_x509_check(x, (char *)ipout, iplen, flags, GEN_IPADD, NULL);
}

/* Convert IP addresses both IPv4 and IPv6 into an
 * OCTET STRING compatible with RFC3280.
 */

ASN1_OCTET_STRING *
a2i_IPADDRESS(const char *ipasc)
{
  unsigned char ipout[16];
  ASN1_OCTET_STRING *ret;
  int iplen;

  /* If string contains a ':' assume IPv6 */

  iplen = a2i_ipadd(ipout, ipasc);

  if (!iplen)
    return NULL;

  ret = ASN1_OCTET_STRING_new();
  if (!ret)
    return NULL;
  if (!ASN1_OCTET_STRING_set(ret, ipout, iplen)) {
    ASN1_OCTET_STRING_free(ret);
    return NULL;
  }
  return ret;
}

ASN1_OCTET_STRING *
a2i_IPADDRESS_NC(const char *ipasc)
{
  ASN1_OCTET_STRING *ret = NULL;
  unsigned char ipout[32];
  char *iptmp = NULL, *p;
  int iplen1, iplen2;

  p = strchr(ipasc, '/');
  if (!p)
    return NULL;
  iptmp = strdup(ipasc);
  if (!iptmp)
    return NULL;
  p = iptmp + (p - ipasc);
  *p++ = 0;

  iplen1 = a2i_ipadd(ipout, iptmp);

  if (!iplen1)
    goto err;

  iplen2 = a2i_ipadd(ipout + iplen1, p);

  free(iptmp);
  iptmp = NULL;

  if (!iplen2 || (iplen1 != iplen2))
    goto err;

  ret = ASN1_OCTET_STRING_new();
  if (!ret)
    goto err;
  if (!ASN1_OCTET_STRING_set(ret, ipout, iplen1 + iplen2))
    goto err;

  return ret;

 err:
  free(iptmp);
  if (ret)
    ASN1_OCTET_STRING_free(ret);
  return NULL;
}


int
a2i_ipadd(unsigned char *ipout, const char *ipasc)
{
  /* If string contains a ':' assume IPv6 */

  if (strchr(ipasc, ':')) {
    if (!ipv6_from_asc(ipout, ipasc))
      return 0;
    return 16;
  } else {
    if (!ipv4_from_asc(ipout, ipasc))
      return 0;
    return 4;
  }
}

static int
ipv4_from_asc(unsigned char *v4, const char *in)
{
  int a0, a1, a2, a3;
  if (sscanf(in, "%d.%d.%d.%d", &a0, &a1, &a2, &a3) != 4)
    return 0;
  if ((a0 < 0) || (a0 > 255) || (a1 < 0) || (a1 > 255) ||
      (a2 < 0) || (a2 > 255) || (a3 < 0) || (a3 > 255))
    return 0;
  v4[0] = a0;
  v4[1] = a1;
  v4[2] = a2;
  v4[3] = a3;
  return 1;
}

typedef struct {
  /* Temporary store for IPV6 output */
  unsigned char tmp[16];
  /* Total number of bytes in tmp */
  int total;
  /* The position of a zero (corresponding to '::') */
  int zero_pos;
  /* Number of zeroes */
  int zero_cnt;
} IPV6_STAT;


static int
ipv6_from_asc(unsigned char *v6, const char *in)
{
  IPV6_STAT v6stat;

  v6stat.total = 0;
  v6stat.zero_pos = -1;
  v6stat.zero_cnt = 0;

  /* Treat the IPv6 representation as a list of values
   * separated by ':'. The presence of a '::' will parse
   * as one, two or three zero length elements.
   */
  if (!CONF_parse_list(in, ':', 0, ipv6_cb, &v6stat))
    return 0;

  /* Now for some sanity checks */

  if (v6stat.zero_pos == -1) {
    /* If no '::' must have exactly 16 bytes */
    if (v6stat.total != 16)
      return 0;
  } else {
    /* If '::' must have less than 16 bytes */
    if (v6stat.total == 16)
      return 0;
    /* More than three zeroes is an error */
    if (v6stat.zero_cnt > 3)
      return 0;
    /* Can only have three zeroes if nothing else present */
    else if (v6stat.zero_cnt == 3) {
      if (v6stat.total > 0)
        return 0;
    }
    /* Can only have two zeroes if at start or end */
    else if (v6stat.zero_cnt == 2) {
      if ((v6stat.zero_pos != 0) &&
          (v6stat.zero_pos != v6stat.total))
        return 0;
    } else
      /* Can only have one zero if *not* start or end */
    {
      if ((v6stat.zero_pos == 0) ||
          (v6stat.zero_pos == v6stat.total))
        return 0;
    }
  }

  /* Format result */

  if (v6stat.zero_pos >= 0) {
    /* Copy initial part */
    memcpy(v6, v6stat.tmp, v6stat.zero_pos);
    /* Zero middle */
    memset(v6 + v6stat.zero_pos, 0, 16 - v6stat.total);
    /* Copy final part */
    if (v6stat.total != v6stat.zero_pos)
      memcpy(v6 + v6stat.zero_pos + 16 - v6stat.total,
          v6stat.tmp + v6stat.zero_pos,
          v6stat.total - v6stat.zero_pos);
  } else
    memcpy(v6, v6stat.tmp, 16);

  return 1;
}

static int
ipv6_cb(const char *elem, int len, void *usr)
{
  IPV6_STAT *s = usr;

  /* Error if 16 bytes written */
  if (s->total == 16)
    return 0;
  if (len == 0) {
    /* Zero length element, corresponds to '::' */
    if (s->zero_pos == -1)
      s->zero_pos = s->total;
    /* If we've already got a :: its an error */
    else if (s->zero_pos != s->total)
      return 0;
    s->zero_cnt++;
  } else {
    /* If more than 4 characters could be final a.b.c.d form */
    if (len > 4) {
      /* Need at least 4 bytes left */
      if (s->total > 12)
        return 0;
      /* Must be end of string */
      if (elem[len])
        return 0;
      if (!ipv4_from_asc(s->tmp + s->total, elem))
        return 0;
      s->total += 4;
    } else {
      if (!ipv6_hex(s->tmp + s->total, elem, len))
        return 0;
      s->total += 2;
    }
  }
  return 1;
}

/* Convert a string of up to 4 hex digits into the corresponding
 * IPv6 form.
 */

static int
ipv6_hex(unsigned char *out, const char *in, int inlen)
{
  unsigned char c;
  unsigned int num = 0;

  if (inlen > 4)
    return 0;
  while (inlen--) {
    c = *in++;
    num <<= 4;
    if ((c >= '0') && (c <= '9'))
      num |= c - '0';
    else if ((c >= 'A') && (c <= 'F'))
      num |= c - 'A' + 10;
    else if ((c >= 'a') && (c <= 'f'))
      num |=  c - 'a' + 10;
    else
      return 0;
  }
  out[0] = num >> 8;
  out[1] = num & 0xff;
  return 1;
}

int
X509V3_NAME_from_section(X509_NAME *nm, STACK_OF(CONF_VALUE)*dn_sk,
    unsigned long chtype)
{
  CONF_VALUE *v;
  int i, mval;
  char *p, *type;

  if (!nm)
    return 0;

  for (i = 0; i < sk_CONF_VALUE_num(dn_sk); i++) {
    v = sk_CONF_VALUE_value(dn_sk, i);
    type = v->name;
    /* Skip past any leading X. X: X, etc to allow for
     * multiple instances
     */
    for (p = type; *p; p++)
      if ((*p == ':') || (*p == ',') || (*p == '.')) {
        p++;
        if (*p)
          type = p;
        break;
      }
    if (*type == '+') {
      mval = -1;
      type++;
    } else
      mval = 0;
    if (!X509_NAME_add_entry_by_txt(nm, type, chtype,
        (unsigned char *) v->value, -1, -1, mval))
      return 0;
  }
  return 1;
}

Coverage Report

Created: 2022-08-24 06:30