diff options
Diffstat (limited to 'crypto/x509v3/v3_utl.c')
| -rw-r--r-- | crypto/x509v3/v3_utl.c | 427 |
1 files changed, 427 insertions, 0 deletions
diff --git a/crypto/x509v3/v3_utl.c b/crypto/x509v3/v3_utl.c index 94aaebba3e3f..bdd7b95f4570 100644 --- a/crypto/x509v3/v3_utl.c +++ b/crypto/x509v3/v3_utl.c @@ -632,6 +632,433 @@ 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; + } +} + +/* Compare while ASCII ignoring case. */ +static int equal_nocase(const unsigned char *pattern, size_t pattern_len, + const unsigned char *subject, size_t subject_len, + unsigned int flags) +{ + skip_prefix(&pattern, &pattern_len, subject, subject_len, flags); + if (pattern_len != subject_len) + return 0; + while (pattern_len) { + unsigned char l = *pattern; + unsigned char r = *subject; + /* The pattern must not contain NUL characters. */ + if (l == 0) + return 0; + if (l != r) { + if ('A' <= l && l <= 'Z') + l = (l - 'A') + 'a'; + if ('A' <= r && r <= 'Z') + r = (r - 'A') + 'a'; + if (l != r) + return 0; + } + ++pattern; + ++subject; + --pattern_len; + } + return 1; +} + +/* Compare using memcmp. */ +static int equal_case(const unsigned char *pattern, size_t pattern_len, + const unsigned char *subject, size_t subject_len, + unsigned int flags) +{ + skip_prefix(&pattern, &pattern_len, subject, subject_len, flags); + if (pattern_len != subject_len) + return 0; + return !memcmp(pattern, subject, pattern_len); +} + +/* + * 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 i = 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 (i > 0) { + --i; + if (a[i] == '@' || b[i] == '@') { + if (!equal_nocase(a + i, a_len - i, b + i, a_len - i, 0)) + return 0; + break; + } + } + if (i == 0) + i = a_len; + return equal_case(a, i, b, i, 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 (('a' <= p[i] && p[i] <= 'z') + || ('A' <= p[i] && p[i] <= 'Z') + || ('0' <= p[i] && p[i] <= '9')) { + if ((state & LABEL_START) != 0 + && len - i >= 4 && strncasecmp((char *)&p[i], "xn--", 4) == 0) + state |= LABEL_IDNA; + state &= ~(LABEL_HYPHEN | LABEL_START); + } else if (p[i] == '.') { + if ((state & (LABEL_HYPHEN | LABEL_START)) != 0) + return NULL; + state = LABEL_START; + ++dots; + } else if (p[i] == '-') { + if ((state & LABEL_HYPHEN) != 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 = BUF_strndup((char *)a->data, a->length); + } else { + int astrlen; + unsigned char *astr; + astrlen = ASN1_STRING_to_UTF8(&astr, a); + if (astrlen < 0) { + /* + * -1 could be an internal malloc failure or a decoding error from + * malformed input; we can't distinguish. + */ + return -1; + } + rv = equal(astr, astrlen, (unsigned char *)b, blen, flags); + if (rv > 0 && peername) + *peername = BUF_strndup((char *)astr, astrlen); + OPENSSL_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; + int i; + int cnid; + 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) { + 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 { + cnid = 0; + alt_type = V_ASN1_OCTET_STRING; + equal = equal_case; + } + + if (chklen == 0) + chklen = strlen(chk); + + gens = X509_get_ext_d2i(x, NID_subject_alt_name, NULL, NULL); + if (gens) { + 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 + || (san_present + && !(flags & X509_CHECK_FLAG_ALWAYS_CHECK_SUBJECT))) + return 0; + } + i = -1; + name = X509_get_subject_name(x); + while ((i = X509_NAME_get_index_by_NID(name, cnid, i)) >= 0) { + X509_NAME_ENTRY *ne; + ASN1_STRING *str; + ne = X509_NAME_get_entry(name, i); + str = X509_NAME_ENTRY_get_data(ne); + /* 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; + /* + * Embedded NULs are disallowed, except as the last character of a + * string of length 2 or more (tolerate caller including terminating + * NUL in string length). + */ + if (chklen == 0) + chklen = strlen(chk); + else if (memchr(chk, '\0', chklen > 1 ? chklen - 1 : chklen)) + return -2; + if (chklen > 1 && chk[chklen - 1] == '\0') + --chklen; + 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; + /* + * Embedded NULs are disallowed, except as the last character of a + * string of length 2 or more (tolerate caller including terminating + * NUL in string length). + */ + if (chklen == 0) + chklen = strlen((char *)chk); + else if (memchr(chk, '\0', chklen > 1 ? chklen - 1 : chklen)) + return -2; + if (chklen > 1 && chk[chklen - 1] == '\0') + --chklen; + 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. |