.\" DO NOT MODIFY THIS FILE!  It was generated by gdoc.
.TH "gnutls_certificate_verify_peers" 3 "3.7.1" "gnutls" "gnutls"
.SH NAME
gnutls_certificate_verify_peers \- API function
.SH SYNOPSIS
.B #include <gnutls/gnutls.h>
.sp
.BI "int gnutls_certificate_verify_peers(gnutls_session_t " session ", gnutls_typed_vdata_st * " data ", unsigned int " elements ", unsigned int * " status ");"
.SH ARGUMENTS
.IP "gnutls_session_t session" 12
is a gnutls session
.IP "gnutls_typed_vdata_st * data" 12
an array of typed data
.IP "unsigned int elements" 12
the number of data elements
.IP "unsigned int * status" 12
is the output of the verification
.SH "DESCRIPTION"
This function will verify the peer's certificate and store the
the status in the  \fIstatus\fP variable as a bitwise OR of gnutls_certificate_status_t
values or zero if the certificate is trusted. Note that value in  \fIstatus\fP is set only when the return value of this function is success (i.e, failure 
to trust a certificate does not imply a negative return value).
The default verification flags used by this function can be overridden
using \fBgnutls_certificate_set_verify_flags()\fP. See the documentation
of \fBgnutls_certificate_verify_peers2()\fP for details in the verification process.

This function will take into account the stapled OCSP responses sent by the server,
as well as the following X.509 certificate extensions: Name Constraints,
Key Usage, and Basic Constraints (pathlen).

The acceptable  \fIdata\fP types are \fBGNUTLS_DT_DNS_HOSTNAME\fP, \fBGNUTLS_DT_RFC822NAME\fP and \fBGNUTLS_DT_KEY_PURPOSE_OID\fP.
The former two accept as data a null\-terminated hostname or email address, and the latter a null\-terminated
object identifier (e.g., \fBGNUTLS_KP_TLS_WWW_SERVER\fP).

If a DNS hostname is provided then this function will compare
the hostname in the certificate against the given. If names do not match the 
\fBGNUTLS_CERT_UNEXPECTED_OWNER\fP status flag will be set.
If a key purpose OID is provided and the end\-certificate contains the extended key
usage PKIX extension, it will be required to be have the provided key purpose 
or be marked for any purpose, otherwise verification status will have the
\fBGNUTLS_CERT_SIGNER_CONSTRAINTS_FAILURE\fP flag set.

To avoid denial of service attacks some
default upper limits regarding the certificate key size and chain
size are set. To override them use \fBgnutls_certificate_set_verify_limits()\fP.

Note that when using raw public\-keys verification will not work because there is
no corresponding certificate body belonging to the raw key that can be verified. In that
case this function will return \fBGNUTLS_E_INVALID_REQUEST\fP.
.SH "RETURNS"
\fBGNUTLS_E_SUCCESS\fP (0) when the validation is performed, or a negative error code otherwise.
A successful error code means that the  \fIstatus\fP parameter must be checked to obtain the validation status.
.SH "SINCE"
3.3.0
.SH "REPORTING BUGS"
Report bugs to <bugs@gnutls.org>.
.br
Home page: https://www.gnutls.org

.SH COPYRIGHT
Copyright \(co 2001- Free Software Foundation, Inc., and others.
.br
Copying and distribution of this file, with or without modification,
are permitted in any medium without royalty provided the copyright
notice and this notice are preserved.
.SH "SEE ALSO"
The full documentation for
.B gnutls
is maintained as a Texinfo manual.
If the /usr/share/doc/gnutls/
directory does not contain the HTML form visit
.B
.IP https://www.gnutls.org/manual/
.PP