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diff --git a/openssl-1.1.0h/doc/apps/s_client.pod b/openssl-1.1.0h/doc/apps/s_client.pod new file mode 100644 index 0000000..01a6c5f --- /dev/null +++ b/openssl-1.1.0h/doc/apps/s_client.pod @@ -0,0 +1,619 @@ +=pod + +=head1 NAME + +openssl-s_client, +s_client - SSL/TLS client program + +=head1 SYNOPSIS + +B<openssl> B<s_client> +[B<-help>] +[B<-connect host:port>] +[B<-proxy host:port>] +[B<-unix path>] +[B<-4>] +[B<-6>] +[B<-servername name>] +[B<-verify depth>] +[B<-verify_return_error>] +[B<-cert filename>] +[B<-certform DER|PEM>] +[B<-key filename>] +[B<-keyform DER|PEM>] +[B<-pass arg>] +[B<-CApath directory>] +[B<-CAfile filename>] +[B<-no-CAfile>] +[B<-no-CApath>] +[B<-dane_tlsa_domain domain>] +[B<-dane_tlsa_rrdata rrdata>] +[B<-dane_ee_no_namechecks>] +[B<-attime timestamp>] +[B<-check_ss_sig>] +[B<-crl_check>] +[B<-crl_check_all>] +[B<-explicit_policy>] +[B<-extended_crl>] +[B<-ignore_critical>] +[B<-inhibit_any>] +[B<-inhibit_map>] +[B<-no_check_time>] +[B<-partial_chain>] +[B<-policy arg>] +[B<-policy_check>] +[B<-policy_print>] +[B<-purpose purpose>] +[B<-suiteB_128>] +[B<-suiteB_128_only>] +[B<-suiteB_192>] +[B<-trusted_first>] +[B<-no_alt_chains>] +[B<-use_deltas>] +[B<-auth_level num>] +[B<-verify_depth num>] +[B<-verify_email email>] +[B<-verify_hostname hostname>] +[B<-verify_ip ip>] +[B<-verify_name name>] +[B<-x509_strict>] +[B<-reconnect>] +[B<-showcerts>] +[B<-debug>] +[B<-msg>] +[B<-nbio_test>] +[B<-state>] +[B<-nbio>] +[B<-crlf>] +[B<-ign_eof>] +[B<-no_ign_eof>] +[B<-quiet>] +[B<-ssl3>] +[B<-tls1>] +[B<-tls1_1>] +[B<-tls1_2>] +[B<-no_ssl3>] +[B<-no_tls1>] +[B<-no_tls1_1>] +[B<-no_tls1_2>] +[B<-dtls>] +[B<-dtls1>] +[B<-dtls1_2>] +[B<-fallback_scsv>] +[B<-async>] +[B<-split_send_frag>] +[B<-max_pipelines>] +[B<-read_buf>] +[B<-bugs>] +[B<-comp>] +[B<-no_comp>] +[B<-sigalgs sigalglist>] +[B<-curves curvelist>] +[B<-cipher cipherlist>] +[B<-serverpref>] +[B<-starttls protocol>] +[B<-xmpphost hostname>] +[B<-engine id>] +[B<-tlsextdebug>] +[B<-no_ticket>] +[B<-sess_out filename>] +[B<-sess_in filename>] +[B<-rand file(s)>] +[B<-serverinfo types>] +[B<-status>] +[B<-alpn protocols>] +[B<-nextprotoneg protocols>] +[B<-ct|noct>] +[B<-ctlogfile>] + +=head1 DESCRIPTION + +The B<s_client> command implements a generic SSL/TLS client which connects +to a remote host using SSL/TLS. It is a I<very> useful diagnostic tool for +SSL servers. + +=head1 OPTIONS + +In addition to the options below the B<s_client> utility also supports the +common and client only options documented in the +in the "Supported Command Line Commands" section of the L<SSL_CONF_cmd(3)> +manual page. + +=over 4 + +=item B<-help> + +Print out a usage message. + +=item B<-connect host:port> + +This specifies the host and optional port to connect to. If not specified +then an attempt is made to connect to the local host on port 4433. + +=item B<-proxy host:port> + +When used with the B<-connect> flag, the program uses the host and port +specified with this flag and issues an HTTP CONNECT command to connect +to the desired server. + +=item B<-unix path> + +Connect over the specified Unix-domain socket. + +=item B<-4> + +Use IPv4 only. + +=item B<-6> + +Use IPv6 only. + +=item B<-servername name> + +Set the TLS SNI (Server Name Indication) extension in the ClientHello message. + +=item B<-cert certname> + +The certificate to use, if one is requested by the server. The default is +not to use a certificate. + +=item B<-certform format> + +The certificate format to use: DER or PEM. PEM is the default. + +=item B<-key keyfile> + +The private key to use. If not specified then the certificate file will +be used. + +=item B<-keyform format> + +The private format to use: DER or PEM. PEM is the default. + +=item B<-pass arg> + +the private key password source. For more information about the format of B<arg> +see the B<PASS PHRASE ARGUMENTS> section in L<openssl(1)>. + +=item B<-verify depth> + +The verify depth to use. This specifies the maximum length of the +server certificate chain and turns on server certificate verification. +Currently the verify operation continues after errors so all the problems +with a certificate chain can be seen. As a side effect the connection +will never fail due to a server certificate verify failure. + +=item B<-verify_return_error> + +Return verification errors instead of continuing. This will typically +abort the handshake with a fatal error. + +=item B<-CApath directory> + +The directory to use for server certificate verification. This directory +must be in "hash format", see B<verify> for more information. These are +also used when building the client certificate chain. + +=item B<-CAfile file> + +A file containing trusted certificates to use during server authentication +and to use when attempting to build the client certificate chain. + +=item B<-no-CAfile> + +Do not load the trusted CA certificates from the default file location + +=item B<-no-CApath> + +Do not load the trusted CA certificates from the default directory location + +=item B<-dane_tlsa_domain domain> + +Enable RFC6698/RFC7671 DANE TLSA authentication and specify the +TLSA base domain which becomes the default SNI hint and the primary +reference identifier for hostname checks. This must be used in +combination with at least one instance of the B<-dane_tlsa_rrdata> +option below. + +When DANE authentication succeeds, the diagnostic output will include +the lowest (closest to 0) depth at which a TLSA record authenticated +a chain certificate. When that TLSA record is a "2 1 0" trust +anchor public key that signed (rather than matched) the top-most +certificate of the chain, the result is reported as "TA public key +verified". Otherwise, either the TLSA record "matched TA certificate" +at a positive depth or else "matched EE certificate" at depth 0. + +=item B<-dane_tlsa_rrdata rrdata> + +Use one or more times to specify the RRDATA fields of the DANE TLSA +RRset associated with the target service. The B<rrdata> value is +specied in "presentation form", that is four whitespace separated +fields that specify the usage, selector, matching type and associated +data, with the last of these encoded in hexadecimal. Optional +whitespace is ignored in the associated data field. For example: + + $ openssl s_client -brief -starttls smtp \ + -connect smtp.example.com:25 \ + -dane_tlsa_domain smtp.example.com \ + -dane_tlsa_rrdata "2 1 1 + B111DD8A1C2091A89BD4FD60C57F0716CCE50FEEFF8137CDBEE0326E 02CF362B" \ + -dane_tlsa_rrdata "2 1 1 + 60B87575447DCBA2A36B7D11AC09FB24A9DB406FEE12D2CC90180517 616E8A18" + ... + Verification: OK + Verified peername: smtp.example.com + DANE TLSA 2 1 1 ...ee12d2cc90180517616e8a18 matched TA certificate at depth 1 + ... + +=item B<-dane_ee_no_namechecks> + +This disables server name checks when authenticating via DANE-EE(3) TLSA +records. +For some applications, primarily web browsers, it is not safe to disable name +checks due to "unknown key share" attacks, in which a malicious server can +convince a client that a connection to a victim server is instead a secure +connection to the malicious server. +The malicious server may then be able to violate cross-origin scripting +restrictions. +Thus, despite the text of RFC7671, name checks are by default enabled for +DANE-EE(3) TLSA records, and can be disabled in applications where it is safe +to do so. +In particular, SMTP and XMPP clients should set this option as SRV and MX +records already make it possible for a remote domain to redirect client +connections to any server of its choice, and in any case SMTP and XMPP clients +do not execute scripts downloaded from remote servers. + +=item B<-attime>, B<-check_ss_sig>, B<-crl_check>, B<-crl_check_all>, +B<-explicit_policy>, B<-extended_crl>, B<-ignore_critical>, B<-inhibit_any>, +B<-inhibit_map>, B<-no_alt_chains>, B<-no_check_time>, B<-partial_chain>, B<-policy>, +B<-policy_check>, B<-policy_print>, B<-purpose>, B<-suiteB_128>, +B<-suiteB_128_only>, B<-suiteB_192>, B<-trusted_first>, B<-use_deltas>, +B<-auth_level>, B<-verify_depth>, B<-verify_email>, B<-verify_hostname>, +B<-verify_ip>, B<-verify_name>, B<-x509_strict> + +Set various certificate chain validation options. See the +L<verify(1)> manual page for details. + +=item B<-reconnect> + +reconnects to the same server 5 times using the same session ID, this can +be used as a test that session caching is working. + +=item B<-showcerts> + +display the whole server certificate chain: normally only the server +certificate itself is displayed. + +=item B<-prexit> + +print session information when the program exits. This will always attempt +to print out information even if the connection fails. Normally information +will only be printed out once if the connection succeeds. This option is useful +because the cipher in use may be renegotiated or the connection may fail +because a client certificate is required or is requested only after an +attempt is made to access a certain URL. Note: the output produced by this +option is not always accurate because a connection might never have been +established. + +=item B<-state> + +prints out the SSL session states. + +=item B<-debug> + +print extensive debugging information including a hex dump of all traffic. + +=item B<-msg> + +show all protocol messages with hex dump. + +=item B<-trace> + +show verbose trace output of protocol messages. OpenSSL needs to be compiled +with B<enable-ssl-trace> for this option to work. + +=item B<-msgfile> + +file to send output of B<-msg> or B<-trace> to, default standard output. + +=item B<-nbio_test> + +tests non-blocking I/O + +=item B<-nbio> + +turns on non-blocking I/O + +=item B<-crlf> + +this option translated a line feed from the terminal into CR+LF as required +by some servers. + +=item B<-ign_eof> + +inhibit shutting down the connection when end of file is reached in the +input. + +=item B<-quiet> + +inhibit printing of session and certificate information. This implicitly +turns on B<-ign_eof> as well. + +=item B<-no_ign_eof> + +shut down the connection when end of file is reached in the input. +Can be used to override the implicit B<-ign_eof> after B<-quiet>. + +=item B<-psk_identity identity> + +Use the PSK identity B<identity> when using a PSK cipher suite. +The default value is "Client_identity" (without the quotes). + +=item B<-psk key> + +Use the PSK key B<key> when using a PSK cipher suite. The key is +given as a hexadecimal number without leading 0x, for example -psk +1a2b3c4d. +This option must be provided in order to use a PSK cipher. + +=item B<-ssl3>, B<-tls1>, B<-tls1_1>, B<-tls1_2>, B<-no_ssl3>, B<-no_tls1>, B<-no_tls1_1>, B<-no_tls1_2> + +These options require or disable the use of the specified SSL or TLS protocols. +By default B<s_client> will negotiate the highest mutually supported protocol +version. +When a specific TLS version is required, only that version will be offered to +and accepted from the server. + +=item B<-dtls>, B<-dtls1>, B<-dtls1_2> + +These options make B<s_client> use DTLS protocols instead of TLS. +With B<-dtls>, B<s_client> will negotiate any supported DTLS protocol version, +whilst B<-dtls1> and B<-dtls1_2> will only support DTLS1.0 and DTLS1.2 +respectively. + +=item B<-fallback_scsv> + +Send TLS_FALLBACK_SCSV in the ClientHello. + +=item B<-async> + +switch on asynchronous mode. Cryptographic operations will be performed +asynchronously. This will only have an effect if an asynchronous capable engine +is also used via the B<-engine> option. For test purposes the dummy async engine +(dasync) can be used (if available). + +=item B<-split_send_frag int> + +The size used to split data for encrypt pipelines. If more data is written in +one go than this value then it will be split into multiple pipelines, up to the +maximum number of pipelines defined by max_pipelines. This only has an effect if +a suitable ciphersuite has been negotiated, an engine that supports pipelining +has been loaded, and max_pipelines is greater than 1. See +L<SSL_CTX_set_split_send_fragment(3)> for further information. + +=item B<-max_pipelines int> + +The maximum number of encrypt/decrypt pipelines to be used. This will only have +an effect if an engine has been loaded that supports pipelining (e.g. the dasync +engine) and a suitable ciphersuite has been negotiated. The default value is 1. +See L<SSL_CTX_set_max_pipelines(3)> for further information. + +=item B<-read_buf int> + +The default read buffer size to be used for connections. This will only have an +effect if the buffer size is larger than the size that would otherwise be used +and pipelining is in use (see L<SSL_CTX_set_default_read_buffer_len(3)> for +further information). + +=item B<-bugs> + +there are several known bug in SSL and TLS implementations. Adding this +option enables various workarounds. + +=item B<-comp> + +Enables support for SSL/TLS compression. +This option was introduced in OpenSSL 1.1.0. +TLS compression is not recommended and is off by default as of +OpenSSL 1.1.0. + +=item B<-no_comp> + +Disables support for SSL/TLS compression. +TLS compression is not recommended and is off by default as of +OpenSSL 1.1.0. + +=item B<-brief> + +only provide a brief summary of connection parameters instead of the +normal verbose output. + +=item B<-sigalgs sigalglist> + +Specifies the list of signature algorithms that are sent by the client. +The server selects one entry in the list based on its preferences. +For example strings, see L<SSL_CTX_set1_sigalgs(3)> + +=item B<-curves curvelist> + +Specifies the list of supported curves to be sent by the client. The curve is +is ultimately selected by the server. For a list of all curves, use: + + $ openssl ecparam -list_curves + +=item B<-cipher cipherlist> + +this allows the cipher list sent by the client to be modified. Although +the server determines which cipher suite is used it should take the first +supported cipher in the list sent by the client. See the B<ciphers> +command for more information. + +=item B<-starttls protocol> + +send the protocol-specific message(s) to switch to TLS for communication. +B<protocol> is a keyword for the intended protocol. Currently, the only +supported keywords are "smtp", "pop3", "imap", "ftp", "xmpp", "xmpp-server", +and "irc." + +=item B<-xmpphost hostname> + +This option, when used with "-starttls xmpp" or "-starttls xmpp-server", +specifies the host for the "to" attribute of the stream element. +If this option is not specified, then the host specified with "-connect" +will be used. + +=item B<-tlsextdebug> + +print out a hex dump of any TLS extensions received from the server. + +=item B<-no_ticket> + +disable RFC4507bis session ticket support. + +=item B<-sess_out filename> + +output SSL session to B<filename> + +=item B<-sess_in sess.pem> + +load SSL session from B<filename>. The client will attempt to resume a +connection from this session. + +=item B<-engine id> + +specifying an engine (by its unique B<id> string) will cause B<s_client> +to attempt to obtain a functional reference to the specified engine, +thus initialising it if needed. The engine will then be set as the default +for all available algorithms. + +=item B<-rand file(s)> + +a file or files containing random data used to seed the random number +generator, or an EGD socket (see L<RAND_egd(3)>). +Multiple files can be specified separated by an OS-dependent character. +The separator is B<;> for MS-Windows, B<,> for OpenVMS, and B<:> for +all others. + +=item B<-serverinfo types> + +a list of comma-separated TLS Extension Types (numbers between 0 and +65535). Each type will be sent as an empty ClientHello TLS Extension. +The server's response (if any) will be encoded and displayed as a PEM +file. + +=item B<-status> + +sends a certificate status request to the server (OCSP stapling). The server +response (if any) is printed out. + +=item B<-alpn protocols>, B<-nextprotoneg protocols> + +these flags enable the +Enable the Application-Layer Protocol Negotiation or Next Protocol +Negotiation extension, respectively. ALPN is the IETF standard and +replaces NPN. +The B<protocols> list is a +comma-separated protocol names that the client should advertise +support for. The list should contain most wanted protocols first. +Protocol names are printable ASCII strings, for example "http/1.1" or +"spdy/3". +Empty list of protocols is treated specially and will cause the client to +advertise support for the TLS extension but disconnect just after +receiving ServerHello with a list of server supported protocols. + +=item B<-ct|noct> + +Use one of these two options to control whether Certificate Transparency (CT) +is enabled (B<-ct>) or disabled (B<-noct>). +If CT is enabled, signed certificate timestamps (SCTs) will be requested from +the server and reported at handshake completion. + +Enabling CT also enables OCSP stapling, as this is one possible delivery method +for SCTs. + +=item B<-ctlogfile> + +A file containing a list of known Certificate Transparency logs. See +L<SSL_CTX_set_ctlog_list_file(3)> for the expected file format. + +=back + +=head1 CONNECTED COMMANDS + +If a connection is established with an SSL server then any data received +from the server is displayed and any key presses will be sent to the +server. When used interactively (which means neither B<-quiet> nor B<-ign_eof> +have been given), the session will be renegotiated if the line begins with an +B<R>, and if the line begins with a B<Q> or if end of file is reached, the +connection will be closed down. + +=head1 NOTES + +B<s_client> can be used to debug SSL servers. To connect to an SSL HTTP +server the command: + + openssl s_client -connect servername:443 + +would typically be used (https uses port 443). If the connection succeeds +then an HTTP command can be given such as "GET /" to retrieve a web page. + +If the handshake fails then there are several possible causes, if it is +nothing obvious like no client certificate then the B<-bugs>, +B<-ssl3>, B<-tls1>, B<-no_ssl3>, B<-no_tls1> options can be tried +in case it is a buggy server. In particular you should play with these +options B<before> submitting a bug report to an OpenSSL mailing list. + +A frequent problem when attempting to get client certificates working +is that a web client complains it has no certificates or gives an empty +list to choose from. This is normally because the server is not sending +the clients certificate authority in its "acceptable CA list" when it +requests a certificate. By using B<s_client> the CA list can be viewed +and checked. However some servers only request client authentication +after a specific URL is requested. To obtain the list in this case it +is necessary to use the B<-prexit> option and send an HTTP request +for an appropriate page. + +If a certificate is specified on the command line using the B<-cert> +option it will not be used unless the server specifically requests +a client certificate. Therefor merely including a client certificate +on the command line is no guarantee that the certificate works. + +If there are problems verifying a server certificate then the +B<-showcerts> option can be used to show the whole chain. + +The B<s_client> utility is a test tool and is designed to continue the +handshake after any certificate verification errors. As a result it will +accept any certificate chain (trusted or not) sent by the peer. None test +applications should B<not> do this as it makes them vulnerable to a MITM +attack. This behaviour can be changed by with the B<-verify_return_error> +option: any verify errors are then returned aborting the handshake. + +=head1 BUGS + +Because this program has a lot of options and also because some of the +techniques used are rather old, the C source of B<s_client> is rather hard to +read and not a model of how things should be done. +A typical SSL client program would be much simpler. + +The B<-prexit> option is a bit of a hack. We should really report +information whenever a session is renegotiated. + +=head1 SEE ALSO + +L<SSL_CONF_cmd(3)>, +L<sess_id(1)>, L<s_server(1)>, L<ciphers(1)> + +=head1 HISTORY + +The -no_alt_chains options was first added to OpenSSL 1.1.0. + +=head1 COPYRIGHT + +Copyright 2000-2016 The OpenSSL Project Authors. All Rights Reserved. + +Licensed under the OpenSSL license (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 |