mirror of
https://github.com/openssl/openssl.git
synced 2024-12-15 06:01:37 +08:00
165 lines
6.6 KiB
Plaintext
165 lines
6.6 KiB
Plaintext
=pod
|
|
|
|
=head1 NAME
|
|
|
|
X509_check_host, X509_check_email, X509_check_ip, X509_check_ip_asc - X.509 certificate matching
|
|
|
|
=head1 SYNOPSIS
|
|
|
|
#include <openssl/x509v3.h>
|
|
|
|
int X509_check_host(X509 *, const char *name, size_t namelen,
|
|
unsigned int flags, char **peername);
|
|
int X509_check_email(X509 *, const char *address, size_t addresslen,
|
|
unsigned int flags);
|
|
int X509_check_ip(X509 *, const unsigned char *address, size_t addresslen,
|
|
unsigned int flags);
|
|
int X509_check_ip_asc(X509 *, const char *address, unsigned int flags);
|
|
|
|
=head1 DESCRIPTION
|
|
|
|
The certificate matching functions are used to check whether a
|
|
certificate matches a given hostname, email address, or IP address.
|
|
The validity of the certificate and its trust level has to be checked by
|
|
other means.
|
|
|
|
X509_check_host() checks if the certificate Subject Alternative
|
|
Name (SAN) or Subject CommonName (CN) matches the specified hostname,
|
|
which must be encoded in the preferred name syntax described
|
|
in section 3.5 of RFC 1034. By default, wildcards are supported
|
|
and they match only in the left-most label; but they may match
|
|
part of that label with an explicit prefix or suffix. For example,
|
|
by default, the host B<name> "www.example.com" would match a
|
|
certificate with a SAN or CN value of "*.example.com", "w*.example.com"
|
|
or "*w.example.com".
|
|
|
|
Per section 6.4.2 of RFC 6125, B<name> values representing international
|
|
domain names must be given in A-label form. The B<namelen> argument
|
|
must be the number of characters in the name string or zero in which
|
|
case the length is calculated with strlen(B<name>). When B<name> starts
|
|
with a dot (e.g. ".example.com"), it will be matched by a certificate
|
|
valid for any sub-domain of B<name>, (see also
|
|
B<X509_CHECK_FLAG_SINGLE_LABEL_SUBDOMAINS> below).
|
|
|
|
When the certificate is matched, and B<peername> is not NULL, a
|
|
pointer to a copy of the matching SAN or CN from the peer certificate
|
|
is stored at the address passed in B<peername>. The application
|
|
is responsible for freeing the peername via OPENSSL_free() when it
|
|
is no longer needed.
|
|
|
|
X509_check_email() checks if the certificate matches the specified
|
|
email B<address>. The mailbox syntax of RFC 822 is supported,
|
|
comments are not allowed, and no attempt is made to normalize quoted
|
|
characters. The mailbox syntax of RFC 6531 is supported for
|
|
SmtpUTF8Mailbox address in subjectAltName according to RFC 8398,
|
|
with similar limitations as for RFC 822 syntax, and no attempt
|
|
is made to convert from A-label to U-label before comparison.
|
|
The B<addresslen> argument must be the number of
|
|
characters in the address string or zero in which case the length
|
|
is calculated with strlen(B<address>).
|
|
|
|
X509_check_ip() checks if the certificate matches a specified IPv4 or
|
|
IPv6 address. The B<address> array is in binary format, in network
|
|
byte order. The length is either 4 (IPv4) or 16 (IPv6). Only
|
|
explicitly marked addresses in the certificates are considered; IP
|
|
addresses stored in DNS names and Common Names are ignored. There are
|
|
currently no B<flags> that would affect the behavior of this call.
|
|
|
|
X509_check_ip_asc() is similar, except that the NUL-terminated
|
|
string B<address> is first converted to the internal representation.
|
|
|
|
The B<flags> argument is usually 0. It can be the bitwise OR of the
|
|
flags:
|
|
|
|
=over 4
|
|
|
|
=item B<X509_CHECK_FLAG_ALWAYS_CHECK_SUBJECT>,
|
|
|
|
=item B<X509_CHECK_FLAG_NEVER_CHECK_SUBJECT>,
|
|
|
|
=item B<X509_CHECK_FLAG_NO_WILDCARDS>,
|
|
|
|
=item B<X509_CHECK_FLAG_NO_PARTIAL_WILDCARDS>,
|
|
|
|
=item B<X509_CHECK_FLAG_MULTI_LABEL_WILDCARDS>.
|
|
|
|
=item B<X509_CHECK_FLAG_SINGLE_LABEL_SUBDOMAINS>.
|
|
|
|
=back
|
|
|
|
The B<X509_CHECK_FLAG_ALWAYS_CHECK_SUBJECT> flag causes the function
|
|
to consider the subject DN even if the certificate contains at least
|
|
one subject alternative name of the right type (DNS name or email
|
|
address as appropriate); the default is to ignore the subject DN
|
|
when at least one corresponding subject alternative names is present.
|
|
|
|
The B<X509_CHECK_FLAG_NEVER_CHECK_SUBJECT> flag causes the function to never
|
|
consider the subject DN even if the certificate contains no subject alternative
|
|
names of the right type (DNS name or email address as appropriate); the default
|
|
is to use the subject DN when no corresponding subject alternative names are
|
|
present.
|
|
If both B<X509_CHECK_FLAG_ALWAYS_CHECK_SUBJECT> and
|
|
B<X509_CHECK_FLAG_NEVER_CHECK_SUBJECT> are specified, the latter takes
|
|
precedence and the subject DN is not checked for matching names.
|
|
|
|
If set, B<X509_CHECK_FLAG_NO_WILDCARDS> disables wildcard
|
|
expansion; this only applies to B<X509_check_host>.
|
|
|
|
If set, B<X509_CHECK_FLAG_NO_PARTIAL_WILDCARDS> suppresses support
|
|
for "*" as wildcard pattern in labels that have a prefix or suffix,
|
|
such as: "www*" or "*www"; this only applies to B<X509_check_host>.
|
|
|
|
If set, B<X509_CHECK_FLAG_MULTI_LABEL_WILDCARDS> allows a "*" that
|
|
constitutes the complete label of a DNS name (e.g. "*.example.com")
|
|
to match more than one label in B<name>; this flag only applies
|
|
to B<X509_check_host>.
|
|
|
|
If set, B<X509_CHECK_FLAG_SINGLE_LABEL_SUBDOMAINS> restricts B<name>
|
|
values which start with ".", that would otherwise match any sub-domain
|
|
in the peer certificate, to only match direct child sub-domains.
|
|
Thus, for instance, with this flag set a B<name> of ".example.com"
|
|
would match a peer certificate with a DNS name of "www.example.com",
|
|
but would not match a peer certificate with a DNS name of
|
|
"www.sub.example.com"; this flag only applies to B<X509_check_host>.
|
|
|
|
=head1 RETURN VALUES
|
|
|
|
The functions return 1 for a successful match, 0 for a failed match
|
|
and -1 for an internal error: typically a memory allocation failure
|
|
or an ASN.1 decoding error.
|
|
|
|
All functions can also return -2 if the input is malformed. For example,
|
|
X509_check_host() returns -2 if the provided B<name> contains embedded
|
|
NULs.
|
|
|
|
=head1 NOTES
|
|
|
|
Applications are encouraged to use X509_VERIFY_PARAM_set1_host()
|
|
rather than explicitly calling L<X509_check_host(3)>. Hostname
|
|
checks may be out of scope with the DANE-EE(3) certificate usage,
|
|
and the internal checks will be suppressed as appropriate when
|
|
DANE support is enabled.
|
|
|
|
=head1 SEE ALSO
|
|
|
|
L<SSL_get_verify_result(3)>,
|
|
L<X509_VERIFY_PARAM_set1_host(3)>,
|
|
L<X509_VERIFY_PARAM_add1_host(3)>,
|
|
L<X509_VERIFY_PARAM_set1_email(3)>,
|
|
L<X509_VERIFY_PARAM_set1_ip(3)>
|
|
|
|
=head1 HISTORY
|
|
|
|
These functions were added in OpenSSL 1.0.2.
|
|
|
|
=head1 COPYRIGHT
|
|
|
|
Copyright 2012-2022 The OpenSSL Project Authors. All Rights Reserved.
|
|
|
|
Licensed under the Apache License 2.0 (the "License"). You may not use
|
|
this file except in compliance with the License. You can obtain a copy
|
|
in the file LICENSE in the source distribution or at
|
|
L<https://www.openssl.org/source/license.html>.
|
|
|
|
=cut
|