.\" $OpenBSD: tls_conn_version.3,v 1.9 2018/12/14 20:18:27 schwarze Exp $
.\"
.\" Copyright (c) 2015 Bob Beck <beck@openbsd.org>
.\" Copyright (c) 2016, 2018 Joel Sing <jsing@openbsd.org>
.\"
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.\" purpose with or without fee is hereby granted, provided that the above
.\" copyright notice and this permission notice appear in all copies.
.\"
.\" THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
.\" WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
.\" MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
.\" ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
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.\" OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
.\"
.Dd $Mdocdate: December 14 2018 $
.Dt TLS_CONN_VERSION 3
.Os
.Sh NAME
.Nm tls_conn_version ,
.Nm tls_conn_cipher ,
.Nm tls_conn_alpn_selected ,
.Nm tls_conn_servername ,
.Nm tls_conn_session_resumed ,
.Nm tls_peer_cert_provided ,
.Nm tls_peer_cert_contains_name ,
.Nm tls_peer_cert_chain_pem ,
.Nm tls_peer_cert_issuer ,
.Nm tls_peer_cert_subject ,
.Nm tls_peer_cert_hash ,
.Nm tls_peer_cert_notbefore ,
.Nm tls_peer_cert_notafter
.Nd inspect an established TLS connection
.Sh SYNOPSIS
.In tls.h
.Ft const char *
.Fn tls_conn_version "struct tls *ctx"
.Ft const char *
.Fn tls_conn_cipher "struct tls *ctx"
.Ft const char *
.Fn tls_conn_alpn_selected "struct tls *ctx"
.Ft const char *
.Fn tls_conn_servername "struct tls *ctx"
.Ft int
.Fn tls_conn_session_resumed "struct tls *ctx"
.Ft int
.Fn tls_peer_cert_provided "struct tls *ctx"
.Ft int
.Fo tls_peer_cert_contains_name
.Fa "struct tls *ctx"
.Fa "const char *name"
.Fc
.Ft const uint8_t *
.Fo tls_peer_cert_chain_pem
.Fa "struct tls *ctx"
.Fa "size_t *size"
.Fc
.Ft const char *
.Fn tls_peer_cert_issuer "struct tls *ctx"
.Ft const char *
.Fn tls_peer_cert_subject "struct tls *ctx"
.Ft const char *
.Fn tls_peer_cert_hash "struct tls *ctx"
.Ft time_t
.Fn tls_peer_cert_notbefore "struct tls *ctx"
.Ft time_t
.Fn tls_peer_cert_notafter "struct tls *ctx"
.Sh DESCRIPTION
These functions return information about a TLS connection and will only
succeed after the handshake is complete (the connection information applies
to both clients and servers, unless noted otherwise):
.Pp
.Fn tls_conn_version
returns a string corresponding to a TLS version negotiated with the peer
connected to
.Ar ctx .
.Pp
.Fn tls_conn_cipher
returns a string corresponding to the cipher suite negotiated with the peer
connected to
.Ar ctx .
.Pp
.Fn tls_conn_alpn_selected
returns a string that specifies the ALPN protocol selected for use with the peer
connected to
.Ar ctx .
If no protocol was selected then NULL is returned.
.Pp
.Fn tls_conn_servername
returns a string corresponding to the servername that the client connected to
.Ar ctx
requested by sending a TLS Server Name Indication extension (server only).
.Pp
.Fn tls_conn_session_resumed
indicates whether a TLS session has been resumed during the handshake with
the server connected to
.Ar ctx
(client only).
.Pp
.Fn tls_peer_cert_provided
checks if the peer of
.Ar ctx
has provided a certificate.
.Pp
.Fn tls_peer_cert_contains_name
checks if the peer of a TLS
.Ar ctx
has provided a certificate that contains a
SAN or CN that matches
.Ar name .
.Pp
.Fn tls_peer_cert_chain_pem
returns a pointer to memory containing a PEM-encoded certificate chain for the
peer certificate from
.Ar ctx .
.Pp
.Fn tls_peer_cert_subject
returns a string
corresponding to the subject of the peer certificate from
.Ar ctx .
.Pp
.Fn tls_peer_cert_issuer
returns a string
corresponding to the issuer of the peer certificate from
.Ar ctx .
.Pp
.Fn tls_peer_cert_hash
returns a string
corresponding to a hash of the raw peer certificate from
.Ar ctx
prefixed by a hash name followed by a colon.
The hash currently used is SHA256, though this
could change in the future.
The hash string for a certificate in file
.Ar mycert.crt
can be generated using the commands:
.Bd -literal -offset indent
h=$(openssl x509 -outform der -in mycert.crt | sha256)
printf "SHA256:${h}\\n"
.Ed
.Pp
.Fn tls_peer_cert_notbefore
returns the time corresponding to the start of the validity period of
the peer certificate from
.Ar ctx .
.Pp
.Fn tls_peer_cert_notafter
returns the time corresponding to the end of the validity period of
the peer certificate from
.Ar ctx .
.Sh RETURN VALUES
The
.Fn tls_conn_session_resumed
function returns 1 if a TLS session was resumed or 0 if it was not.
.Pp
The
.Fn tls_peer_cert_provided
and
.Fn tls_peer_cert_contains_name
functions return 1 if the check succeeds or 0 if it does not.
.Pp
.Fn tls_peer_cert_notbefore
and
.Fn tls_peer_cert_notafter
return a time in epoch-seconds on success or -1 on error.
.Pp
The functions that return a pointer return
.Dv NULL
on error or an out of memory condition.
.Sh SEE ALSO
.Xr tls_configure 3 ,
.Xr tls_handshake 3 ,
.Xr tls_init 3 ,
.Xr tls_ocsp_process_response 3
.Sh HISTORY
.Fn tls_conn_version ,
.Fn tls_conn_cipher ,
.Fn tls_peer_cert_provided ,
.Fn tls_peer_cert_contains_name ,
.Fn tls_peer_cert_issuer ,
.Fn tls_peer_cert_subject ,
.Fn tls_peer_cert_hash ,
.Fn tls_peer_cert_notbefore ,
and
.Fn tls_peer_cert_notafter
appeared in
.Ox 5.9 .
.Pp
.Fn tls_conn_servername
and
.Fn tls_conn_alpn_selected
appeared in
.Ox 6.1 .
.Pp
.Fn tls_conn_session_resumed
appeared in
.Ox 6.3 .
.Sh AUTHORS
.An Bob Beck Aq Mt beck@openbsd.org
.An Joel Sing Aq Mt jsing@openbsd.org