forked from cory/tildefriends
778 lines
34 KiB
Groff
778 lines
34 KiB
Groff
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.\" ========================================================================
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.\"
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.IX Title "SSL_CONF_CMD 3"
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.TH SSL_CONF_CMD 3 "2020-04-21" "1.1.1g" "OpenSSL"
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.\" For nroff, turn off justification. Always turn off hyphenation; it makes
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.\" way too many mistakes in technical documents.
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.if n .ad l
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.nh
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.SH "NAME"
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SSL_CONF_cmd_value_type, SSL_CONF_cmd \- send configuration command
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.SH "SYNOPSIS"
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.IX Header "SYNOPSIS"
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.Vb 1
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\& #include <openssl/ssl.h>
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\&
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\& int SSL_CONF_cmd(SSL_CONF_CTX *cctx, const char *cmd, const char *value);
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\& int SSL_CONF_cmd_value_type(SSL_CONF_CTX *cctx, const char *cmd);
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.Ve
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.SH "DESCRIPTION"
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.IX Header "DESCRIPTION"
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The function \fBSSL_CONF_cmd()\fR performs configuration operation \fBcmd\fR with
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optional parameter \fBvalue\fR on \fBctx\fR. Its purpose is to simplify application
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configuration of \fB\s-1SSL_CTX\s0\fR or \fB\s-1SSL\s0\fR structures by providing a common
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framework for command line options or configuration files.
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.PP
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\&\fBSSL_CONF_cmd_value_type()\fR returns the type of value that \fBcmd\fR refers to.
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.SH "SUPPORTED COMMAND LINE COMMANDS"
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.IX Header "SUPPORTED COMMAND LINE COMMANDS"
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Currently supported \fBcmd\fR names for command lines (i.e. when the
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flag \fB\s-1SSL_CONF_CMDLINE\s0\fR is set) are listed below. Note: all \fBcmd\fR names
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are case sensitive. Unless otherwise stated commands can be used by
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both clients and servers and the \fBvalue\fR parameter is not used. The default
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prefix for command line commands is \fB\-\fR and that is reflected below.
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.IP "\fB\-sigalgs\fR" 4
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.IX Item "-sigalgs"
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This sets the supported signature algorithms for TLSv1.2 and TLSv1.3.
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For clients this
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value is used directly for the supported signature algorithms extension. For
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servers it is used to determine which signature algorithms to support.
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.Sp
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The \fBvalue\fR argument should be a colon separated list of signature algorithms
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in order of decreasing preference of the form \fBalgorithm+hash\fR or
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\&\fBsignature_scheme\fR. \fBalgorithm\fR
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is one of \fB\s-1RSA\s0\fR, \fB\s-1DSA\s0\fR or \fB\s-1ECDSA\s0\fR and \fBhash\fR is a supported algorithm
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\&\s-1OID\s0 short name such as \fB\s-1SHA1\s0\fR, \fB\s-1SHA224\s0\fR, \fB\s-1SHA256\s0\fR, \fB\s-1SHA384\s0\fR of \fB\s-1SHA512\s0\fR.
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Note: algorithm and hash names are case sensitive.
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\&\fBsignature_scheme\fR is one of the signature schemes defined in TLSv1.3,
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specified using the \s-1IETF\s0 name, e.g., \fBecdsa_secp256r1_sha256\fR, \fBed25519\fR,
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or \fBrsa_pss_pss_sha256\fR.
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.Sp
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If this option is not set then all signature algorithms supported by the
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OpenSSL library are permissible.
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.Sp
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Note: algorithms which specify a PKCS#1 v1.5 signature scheme (either by
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using \fB\s-1RSA\s0\fR as the \fBalgorithm\fR or by using one of the \fBrsa_pkcs1_*\fR
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identifiers) are ignored in TLSv1.3 and will not be negotiated.
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.IP "\fB\-client_sigalgs\fR" 4
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.IX Item "-client_sigalgs"
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This sets the supported signature algorithms associated with client
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authentication for TLSv1.2 and TLSv1.3.
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For servers the value is used in the
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\&\fBsignature_algorithms\fR field of a \fBCertificateRequest\fR message.
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For clients it is
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used to determine which signature algorithm to use with the client certificate.
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If a server does not request a certificate this option has no effect.
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.Sp
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The syntax of \fBvalue\fR is identical to \fB\-sigalgs\fR. If not set then
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the value set for \fB\-sigalgs\fR will be used instead.
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.IP "\fB\-groups\fR" 4
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.IX Item "-groups"
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This sets the supported groups. For clients, the groups are
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sent using the supported groups extension. For servers, it is used
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to determine which group to use. This setting affects groups used for
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signatures (in TLSv1.2 and earlier) and key exchange. The first group listed
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will also be used for the \fBkey_share\fR sent by a client in a TLSv1.3
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\&\fBClientHello\fR.
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.Sp
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The \fBvalue\fR argument is a colon separated list of groups. The group can be
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either the \fB\s-1NIST\s0\fR name (e.g. \fBP\-256\fR), some other commonly used name where
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applicable (e.g. \fBX25519\fR) or an OpenSSL \s-1OID\s0 name (e.g \fBprime256v1\fR). Group
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names are case sensitive. The list should be in order of preference with the
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most preferred group first.
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.IP "\fB\-curves\fR" 4
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.IX Item "-curves"
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This is a synonym for the \*(L"\-groups\*(R" command.
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.IP "\fB\-named_curve\fR" 4
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.IX Item "-named_curve"
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This sets the temporary curve used for ephemeral \s-1ECDH\s0 modes. Only used by
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servers
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.Sp
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The \fBvalue\fR argument is a curve name or the special value \fBauto\fR which
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picks an appropriate curve based on client and server preferences. The curve
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can be either the \fB\s-1NIST\s0\fR name (e.g. \fBP\-256\fR) or an OpenSSL \s-1OID\s0 name
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(e.g \fBprime256v1\fR). Curve names are case sensitive.
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.IP "\fB\-cipher\fR" 4
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.IX Item "-cipher"
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Sets the TLSv1.2 and below ciphersuite list to \fBvalue\fR. This list will be
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combined with any configured TLSv1.3 ciphersuites. Note: syntax checking
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of \fBvalue\fR is currently not performed unless a \fB\s-1SSL\s0\fR or \fB\s-1SSL_CTX\s0\fR structure is
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associated with \fBcctx\fR.
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.IP "\fB\-ciphersuites\fR" 4
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.IX Item "-ciphersuites"
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Sets the available ciphersuites for TLSv1.3 to value. This is a simple colon
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(\*(L":\*(R") separated list of TLSv1.3 ciphersuite names in order of preference. This
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list will be combined any configured TLSv1.2 and below ciphersuites.
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See \fBciphers\fR\|(1) for more information.
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.IP "\fB\-cert\fR" 4
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.IX Item "-cert"
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Attempts to use the file \fBvalue\fR as the certificate for the appropriate
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context. It currently uses \fBSSL_CTX_use_certificate_chain_file()\fR if an \fB\s-1SSL_CTX\s0\fR
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structure is set or \fBSSL_use_certificate_file()\fR with filetype \s-1PEM\s0 if an \fB\s-1SSL\s0\fR
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structure is set. This option is only supported if certificate operations
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are permitted.
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.IP "\fB\-key\fR" 4
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.IX Item "-key"
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Attempts to use the file \fBvalue\fR as the private key for the appropriate
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context. This option is only supported if certificate operations
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are permitted. Note: if no \fB\-key\fR option is set then a private key is
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not loaded unless the flag \fB\s-1SSL_CONF_FLAG_REQUIRE_PRIVATE\s0\fR is set.
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.IP "\fB\-dhparam\fR" 4
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.IX Item "-dhparam"
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Attempts to use the file \fBvalue\fR as the set of temporary \s-1DH\s0 parameters for
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the appropriate context. This option is only supported if certificate
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operations are permitted.
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.IP "\fB\-record_padding\fR" 4
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.IX Item "-record_padding"
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Attempts to pad TLSv1.3 records so that they are a multiple of \fBvalue\fR in
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length on send. A \fBvalue\fR of 0 or 1 turns off padding. Otherwise, the
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\&\fBvalue\fR must be >1 or <=16384.
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.IP "\fB\-no_renegotiation\fR" 4
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.IX Item "-no_renegotiation"
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Disables all attempts at renegotiation in TLSv1.2 and earlier, same as setting
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\&\fB\s-1SSL_OP_NO_RENEGOTIATION\s0\fR.
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.IP "\fB\-min_protocol\fR, \fB\-max_protocol\fR" 4
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.IX Item "-min_protocol, -max_protocol"
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Sets the minimum and maximum supported protocol.
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Currently supported protocol values are \fBSSLv3\fR, \fBTLSv1\fR,
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\&\fBTLSv1.1\fR, \fBTLSv1.2\fR, \fBTLSv1.3\fR for \s-1TLS\s0 and \fBDTLSv1\fR, \fBDTLSv1.2\fR for \s-1DTLS,\s0
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and \fBNone\fR for no limit.
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If either bound is not specified then only the other bound applies,
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if specified.
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To restrict the supported protocol versions use these commands rather
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than the deprecated alternative commands below.
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.IP "\fB\-no_ssl3\fR, \fB\-no_tls1\fR, \fB\-no_tls1_1\fR, \fB\-no_tls1_2\fR, \fB\-no_tls1_3\fR" 4
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.IX Item "-no_ssl3, -no_tls1, -no_tls1_1, -no_tls1_2, -no_tls1_3"
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Disables protocol support for SSLv3, TLSv1.0, TLSv1.1, TLSv1.2 or TLSv1.3 by
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setting the corresponding options \fBSSL_OP_NO_SSLv3\fR, \fBSSL_OP_NO_TLSv1\fR,
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\&\fBSSL_OP_NO_TLSv1_1\fR, \fBSSL_OP_NO_TLSv1_2\fR and \fBSSL_OP_NO_TLSv1_3\fR
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respectively. These options are deprecated, instead use \fB\-min_protocol\fR and
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\&\fB\-max_protocol\fR.
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|
|
.IP "\fB\-bugs\fR" 4
|
||
|
|
.IX Item "-bugs"
|
||
|
|
Various bug workarounds are set, same as setting \fB\s-1SSL_OP_ALL\s0\fR.
|
||
|
|
.IP "\fB\-comp\fR" 4
|
||
|
|
.IX Item "-comp"
|
||
|
|
Enables support for \s-1SSL/TLS\s0 compression, same as clearing
|
||
|
|
\&\fB\s-1SSL_OP_NO_COMPRESSION\s0\fR.
|
||
|
|
This command was introduced in OpenSSL 1.1.0.
|
||
|
|
As of OpenSSL 1.1.0, compression is off by default.
|
||
|
|
.IP "\fB\-no_comp\fR" 4
|
||
|
|
.IX Item "-no_comp"
|
||
|
|
Disables support for \s-1SSL/TLS\s0 compression, same as setting
|
||
|
|
\&\fB\s-1SSL_OP_NO_COMPRESSION\s0\fR.
|
||
|
|
As of OpenSSL 1.1.0, compression is off by default.
|
||
|
|
.IP "\fB\-no_ticket\fR" 4
|
||
|
|
.IX Item "-no_ticket"
|
||
|
|
Disables support for session tickets, same as setting \fB\s-1SSL_OP_NO_TICKET\s0\fR.
|
||
|
|
.IP "\fB\-serverpref\fR" 4
|
||
|
|
.IX Item "-serverpref"
|
||
|
|
Use server and not client preference order when determining which cipher suite,
|
||
|
|
signature algorithm or elliptic curve to use for an incoming connection.
|
||
|
|
Equivalent to \fB\s-1SSL_OP_CIPHER_SERVER_PREFERENCE\s0\fR. Only used by servers.
|
||
|
|
.IP "\fB\-prioritize_chacha\fR" 4
|
||
|
|
.IX Item "-prioritize_chacha"
|
||
|
|
Prioritize ChaCha ciphers when the client has a ChaCha20 cipher at the top of
|
||
|
|
its preference list. This usually indicates a client without \s-1AES\s0 hardware
|
||
|
|
acceleration (e.g. mobile) is in use. Equivalent to \fB\s-1SSL_OP_PRIORITIZE_CHACHA\s0\fR.
|
||
|
|
Only used by servers. Requires \fB\-serverpref\fR.
|
||
|
|
.IP "\fB\-no_resumption_on_reneg\fR" 4
|
||
|
|
.IX Item "-no_resumption_on_reneg"
|
||
|
|
set \s-1SSL_OP_NO_SESSION_RESUMPTION_ON_RENEGOTIATION\s0 flag. Only used by servers.
|
||
|
|
.IP "\fB\-legacyrenegotiation\fR" 4
|
||
|
|
.IX Item "-legacyrenegotiation"
|
||
|
|
permits the use of unsafe legacy renegotiation. Equivalent to setting
|
||
|
|
\&\fB\s-1SSL_OP_ALLOW_UNSAFE_LEGACY_RENEGOTIATION\s0\fR.
|
||
|
|
.IP "\fB\-legacy_server_connect\fR, \fB\-no_legacy_server_connect\fR" 4
|
||
|
|
.IX Item "-legacy_server_connect, -no_legacy_server_connect"
|
||
|
|
permits or prohibits the use of unsafe legacy renegotiation for OpenSSL
|
||
|
|
clients only. Equivalent to setting or clearing \fB\s-1SSL_OP_LEGACY_SERVER_CONNECT\s0\fR.
|
||
|
|
Set by default.
|
||
|
|
.IP "\fB\-allow_no_dhe_kex\fR" 4
|
||
|
|
.IX Item "-allow_no_dhe_kex"
|
||
|
|
In TLSv1.3 allow a non\-(ec)dhe based key exchange mode on resumption. This means
|
||
|
|
that there will be no forward secrecy for the resumed session.
|
||
|
|
.IP "\fB\-strict\fR" 4
|
||
|
|
.IX Item "-strict"
|
||
|
|
enables strict mode protocol handling. Equivalent to setting
|
||
|
|
\&\fB\s-1SSL_CERT_FLAG_TLS_STRICT\s0\fR.
|
||
|
|
.IP "\fB\-anti_replay\fR, \fB\-no_anti_replay\fR" 4
|
||
|
|
.IX Item "-anti_replay, -no_anti_replay"
|
||
|
|
Switches replay protection, on or off respectively. With replay protection on,
|
||
|
|
OpenSSL will automatically detect if a session ticket has been used more than
|
||
|
|
once, TLSv1.3 has been negotiated, and early data is enabled on the server. A
|
||
|
|
full handshake is forced if a session ticket is used a second or subsequent
|
||
|
|
time. Anti-Replay is on by default unless overridden by a configuration file and
|
||
|
|
is only used by servers. Anti-replay measures are required for compliance with
|
||
|
|
the TLSv1.3 specification. Some applications may be able to mitigate the replay
|
||
|
|
risks in other ways and in such cases the built-in OpenSSL functionality is not
|
||
|
|
required. Switching off anti-replay is equivalent to \fB\s-1SSL_OP_NO_ANTI_REPLAY\s0\fR.
|
||
|
|
.SH "SUPPORTED CONFIGURATION FILE COMMANDS"
|
||
|
|
.IX Header "SUPPORTED CONFIGURATION FILE COMMANDS"
|
||
|
|
Currently supported \fBcmd\fR names for configuration files (i.e. when the
|
||
|
|
flag \fB\s-1SSL_CONF_FLAG_FILE\s0\fR is set) are listed below. All configuration file
|
||
|
|
\&\fBcmd\fR names are case insensitive so \fBsignaturealgorithms\fR is recognised
|
||
|
|
as well as \fBSignatureAlgorithms\fR. Unless otherwise stated the \fBvalue\fR names
|
||
|
|
are also case insensitive.
|
||
|
|
.PP
|
||
|
|
Note: the command prefix (if set) alters the recognised \fBcmd\fR values.
|
||
|
|
.IP "\fBCipherString\fR" 4
|
||
|
|
.IX Item "CipherString"
|
||
|
|
Sets the ciphersuite list for TLSv1.2 and below to \fBvalue\fR. This list will be
|
||
|
|
combined with any configured TLSv1.3 ciphersuites. Note: syntax
|
||
|
|
checking of \fBvalue\fR is currently not performed unless an \fB\s-1SSL\s0\fR or \fB\s-1SSL_CTX\s0\fR
|
||
|
|
structure is associated with \fBcctx\fR.
|
||
|
|
.IP "\fBCiphersuites\fR" 4
|
||
|
|
.IX Item "Ciphersuites"
|
||
|
|
Sets the available ciphersuites for TLSv1.3 to \fBvalue\fR. This is a simple colon
|
||
|
|
(\*(L":\*(R") separated list of TLSv1.3 ciphersuite names in order of preference. This
|
||
|
|
list will be combined any configured TLSv1.2 and below ciphersuites.
|
||
|
|
See \fBciphers\fR\|(1) for more information.
|
||
|
|
.IP "\fBCertificate\fR" 4
|
||
|
|
.IX Item "Certificate"
|
||
|
|
Attempts to use the file \fBvalue\fR as the certificate for the appropriate
|
||
|
|
context. It currently uses \fBSSL_CTX_use_certificate_chain_file()\fR if an \fB\s-1SSL_CTX\s0\fR
|
||
|
|
structure is set or \fBSSL_use_certificate_file()\fR with filetype \s-1PEM\s0 if an \fB\s-1SSL\s0\fR
|
||
|
|
structure is set. This option is only supported if certificate operations
|
||
|
|
are permitted.
|
||
|
|
.IP "\fBPrivateKey\fR" 4
|
||
|
|
.IX Item "PrivateKey"
|
||
|
|
Attempts to use the file \fBvalue\fR as the private key for the appropriate
|
||
|
|
context. This option is only supported if certificate operations
|
||
|
|
are permitted. Note: if no \fBPrivateKey\fR option is set then a private key is
|
||
|
|
not loaded unless the \fB\s-1SSL_CONF_FLAG_REQUIRE_PRIVATE\s0\fR is set.
|
||
|
|
.IP "\fBChainCAFile\fR, \fBChainCAPath\fR, \fBVerifyCAFile\fR, \fBVerifyCAPath\fR" 4
|
||
|
|
.IX Item "ChainCAFile, ChainCAPath, VerifyCAFile, VerifyCAPath"
|
||
|
|
These options indicate a file or directory used for building certificate
|
||
|
|
chains or verifying certificate chains. These options are only supported
|
||
|
|
if certificate operations are permitted.
|
||
|
|
.IP "\fBRequestCAFile\fR" 4
|
||
|
|
.IX Item "RequestCAFile"
|
||
|
|
This option indicates a file containing a set of certificates in \s-1PEM\s0 form.
|
||
|
|
The subject names of the certificates are sent to the peer in the
|
||
|
|
\&\fBcertificate_authorities\fR extension for \s-1TLS 1.3\s0 (in ClientHello or
|
||
|
|
CertificateRequest) or in a certificate request for previous versions or
|
||
|
|
\&\s-1TLS.\s0
|
||
|
|
.IP "\fBServerInfoFile\fR" 4
|
||
|
|
.IX Item "ServerInfoFile"
|
||
|
|
Attempts to use the file \fBvalue\fR in the \*(L"serverinfo\*(R" extension using the
|
||
|
|
function SSL_CTX_use_serverinfo_file.
|
||
|
|
.IP "\fBDHParameters\fR" 4
|
||
|
|
.IX Item "DHParameters"
|
||
|
|
Attempts to use the file \fBvalue\fR as the set of temporary \s-1DH\s0 parameters for
|
||
|
|
the appropriate context. This option is only supported if certificate
|
||
|
|
operations are permitted.
|
||
|
|
.IP "\fBRecordPadding\fR" 4
|
||
|
|
.IX Item "RecordPadding"
|
||
|
|
Attempts to pad TLSv1.3 records so that they are a multiple of \fBvalue\fR in
|
||
|
|
length on send. A \fBvalue\fR of 0 or 1 turns off padding. Otherwise, the
|
||
|
|
\&\fBvalue\fR must be >1 or <=16384.
|
||
|
|
.IP "\fBSignatureAlgorithms\fR" 4
|
||
|
|
.IX Item "SignatureAlgorithms"
|
||
|
|
This sets the supported signature algorithms for TLSv1.2 and TLSv1.3.
|
||
|
|
For clients this
|
||
|
|
value is used directly for the supported signature algorithms extension. For
|
||
|
|
servers it is used to determine which signature algorithms to support.
|
||
|
|
.Sp
|
||
|
|
The \fBvalue\fR argument should be a colon separated list of signature algorithms
|
||
|
|
in order of decreasing preference of the form \fBalgorithm+hash\fR or
|
||
|
|
\&\fBsignature_scheme\fR. \fBalgorithm\fR
|
||
|
|
is one of \fB\s-1RSA\s0\fR, \fB\s-1DSA\s0\fR or \fB\s-1ECDSA\s0\fR and \fBhash\fR is a supported algorithm
|
||
|
|
\&\s-1OID\s0 short name such as \fB\s-1SHA1\s0\fR, \fB\s-1SHA224\s0\fR, \fB\s-1SHA256\s0\fR, \fB\s-1SHA384\s0\fR of \fB\s-1SHA512\s0\fR.
|
||
|
|
Note: algorithm and hash names are case sensitive.
|
||
|
|
\&\fBsignature_scheme\fR is one of the signature schemes defined in TLSv1.3,
|
||
|
|
specified using the \s-1IETF\s0 name, e.g., \fBecdsa_secp256r1_sha256\fR, \fBed25519\fR,
|
||
|
|
or \fBrsa_pss_pss_sha256\fR.
|
||
|
|
.Sp
|
||
|
|
If this option is not set then all signature algorithms supported by the
|
||
|
|
OpenSSL library are permissible.
|
||
|
|
.Sp
|
||
|
|
Note: algorithms which specify a PKCS#1 v1.5 signature scheme (either by
|
||
|
|
using \fB\s-1RSA\s0\fR as the \fBalgorithm\fR or by using one of the \fBrsa_pkcs1_*\fR
|
||
|
|
identifiers) are ignored in TLSv1.3 and will not be negotiated.
|
||
|
|
.IP "\fBClientSignatureAlgorithms\fR" 4
|
||
|
|
.IX Item "ClientSignatureAlgorithms"
|
||
|
|
This sets the supported signature algorithms associated with client
|
||
|
|
authentication for TLSv1.2 and TLSv1.3.
|
||
|
|
For servers the value is used in the
|
||
|
|
\&\fBsignature_algorithms\fR field of a \fBCertificateRequest\fR message.
|
||
|
|
For clients it is
|
||
|
|
used to determine which signature algorithm to use with the client certificate.
|
||
|
|
If a server does not request a certificate this option has no effect.
|
||
|
|
.Sp
|
||
|
|
The syntax of \fBvalue\fR is identical to \fBSignatureAlgorithms\fR. If not set then
|
||
|
|
the value set for \fBSignatureAlgorithms\fR will be used instead.
|
||
|
|
.IP "\fBGroups\fR" 4
|
||
|
|
.IX Item "Groups"
|
||
|
|
This sets the supported groups. For clients, the groups are
|
||
|
|
sent using the supported groups extension. For servers, it is used
|
||
|
|
to determine which group to use. This setting affects groups used for
|
||
|
|
signatures (in TLSv1.2 and earlier) and key exchange. The first group listed
|
||
|
|
will also be used for the \fBkey_share\fR sent by a client in a TLSv1.3
|
||
|
|
\&\fBClientHello\fR.
|
||
|
|
.Sp
|
||
|
|
The \fBvalue\fR argument is a colon separated list of groups. The group can be
|
||
|
|
either the \fB\s-1NIST\s0\fR name (e.g. \fBP\-256\fR), some other commonly used name where
|
||
|
|
applicable (e.g. \fBX25519\fR) or an OpenSSL \s-1OID\s0 name (e.g \fBprime256v1\fR). Group
|
||
|
|
names are case sensitive. The list should be in order of preference with the
|
||
|
|
most preferred group first.
|
||
|
|
.IP "\fBCurves\fR" 4
|
||
|
|
.IX Item "Curves"
|
||
|
|
This is a synonym for the \*(L"Groups\*(R" command.
|
||
|
|
.IP "\fBMinProtocol\fR" 4
|
||
|
|
.IX Item "MinProtocol"
|
||
|
|
This sets the minimum supported \s-1SSL, TLS\s0 or \s-1DTLS\s0 version.
|
||
|
|
.Sp
|
||
|
|
Currently supported protocol values are \fBSSLv3\fR, \fBTLSv1\fR, \fBTLSv1.1\fR,
|
||
|
|
\&\fBTLSv1.2\fR, \fBTLSv1.3\fR, \fBDTLSv1\fR and \fBDTLSv1.2\fR.
|
||
|
|
The value \fBNone\fR will disable the limit.
|
||
|
|
.IP "\fBMaxProtocol\fR" 4
|
||
|
|
.IX Item "MaxProtocol"
|
||
|
|
This sets the maximum supported \s-1SSL, TLS\s0 or \s-1DTLS\s0 version.
|
||
|
|
.Sp
|
||
|
|
Currently supported protocol values are \fBSSLv3\fR, \fBTLSv1\fR, \fBTLSv1.1\fR,
|
||
|
|
\&\fBTLSv1.2\fR, \fBTLSv1.3\fR, \fBDTLSv1\fR and \fBDTLSv1.2\fR.
|
||
|
|
The value \fBNone\fR will disable the limit.
|
||
|
|
.IP "\fBProtocol\fR" 4
|
||
|
|
.IX Item "Protocol"
|
||
|
|
This can be used to enable or disable certain versions of the \s-1SSL,
|
||
|
|
TLS\s0 or \s-1DTLS\s0 protocol.
|
||
|
|
.Sp
|
||
|
|
The \fBvalue\fR argument is a comma separated list of supported protocols
|
||
|
|
to enable or disable.
|
||
|
|
If a protocol is preceded by \fB\-\fR that version is disabled.
|
||
|
|
.Sp
|
||
|
|
All protocol versions are enabled by default.
|
||
|
|
You need to disable at least one protocol version for this setting have any
|
||
|
|
effect.
|
||
|
|
Only enabling some protocol versions does not disable the other protocol
|
||
|
|
versions.
|
||
|
|
.Sp
|
||
|
|
Currently supported protocol values are \fBSSLv3\fR, \fBTLSv1\fR, \fBTLSv1.1\fR,
|
||
|
|
\&\fBTLSv1.2\fR, \fBTLSv1.3\fR, \fBDTLSv1\fR and \fBDTLSv1.2\fR.
|
||
|
|
The special value \fB\s-1ALL\s0\fR refers to all supported versions.
|
||
|
|
.Sp
|
||
|
|
This can't enable protocols that are disabled using \fBMinProtocol\fR
|
||
|
|
or \fBMaxProtocol\fR, but can disable protocols that are still allowed
|
||
|
|
by them.
|
||
|
|
.Sp
|
||
|
|
The \fBProtocol\fR command is fragile and deprecated; do not use it.
|
||
|
|
Use \fBMinProtocol\fR and \fBMaxProtocol\fR instead.
|
||
|
|
If you do use \fBProtocol\fR, make sure that the resulting range of enabled
|
||
|
|
protocols has no \*(L"holes\*(R", e.g. if \s-1TLS 1.0\s0 and \s-1TLS 1.2\s0 are both enabled, make
|
||
|
|
sure to also leave \s-1TLS 1.1\s0 enabled.
|
||
|
|
.IP "\fBOptions\fR" 4
|
||
|
|
.IX Item "Options"
|
||
|
|
The \fBvalue\fR argument is a comma separated list of various flags to set.
|
||
|
|
If a flag string is preceded \fB\-\fR it is disabled.
|
||
|
|
See the \fBSSL_CTX_set_options\fR\|(3) function for more details of
|
||
|
|
individual options.
|
||
|
|
.Sp
|
||
|
|
Each option is listed below. Where an operation is enabled by default
|
||
|
|
the \fB\-flag\fR syntax is needed to disable it.
|
||
|
|
.Sp
|
||
|
|
\&\fBSessionTicket\fR: session ticket support, enabled by default. Inverse of
|
||
|
|
\&\fB\s-1SSL_OP_NO_TICKET\s0\fR: that is \fB\-SessionTicket\fR is the same as setting
|
||
|
|
\&\fB\s-1SSL_OP_NO_TICKET\s0\fR.
|
||
|
|
.Sp
|
||
|
|
\&\fBCompression\fR: \s-1SSL/TLS\s0 compression support, enabled by default. Inverse
|
||
|
|
of \fB\s-1SSL_OP_NO_COMPRESSION\s0\fR.
|
||
|
|
.Sp
|
||
|
|
\&\fBEmptyFragments\fR: use empty fragments as a countermeasure against a
|
||
|
|
\&\s-1SSL 3.0/TLS 1.0\s0 protocol vulnerability affecting \s-1CBC\s0 ciphers. It
|
||
|
|
is set by default. Inverse of \fB\s-1SSL_OP_DONT_INSERT_EMPTY_FRAGMENTS\s0\fR.
|
||
|
|
.Sp
|
||
|
|
\&\fBBugs\fR: enable various bug workarounds. Same as \fB\s-1SSL_OP_ALL\s0\fR.
|
||
|
|
.Sp
|
||
|
|
\&\fBDHSingle\fR: enable single use \s-1DH\s0 keys, set by default. Inverse of
|
||
|
|
\&\fB\s-1SSL_OP_DH_SINGLE\s0\fR. Only used by servers.
|
||
|
|
.Sp
|
||
|
|
\&\fBECDHSingle\fR: enable single use \s-1ECDH\s0 keys, set by default. Inverse of
|
||
|
|
\&\fB\s-1SSL_OP_ECDH_SINGLE\s0\fR. Only used by servers.
|
||
|
|
.Sp
|
||
|
|
\&\fBServerPreference\fR: use server and not client preference order when
|
||
|
|
determining which cipher suite, signature algorithm or elliptic curve
|
||
|
|
to use for an incoming connection. Equivalent to
|
||
|
|
\&\fB\s-1SSL_OP_CIPHER_SERVER_PREFERENCE\s0\fR. Only used by servers.
|
||
|
|
.Sp
|
||
|
|
\&\fBPrioritizeChaCha\fR: prioritizes ChaCha ciphers when the client has a
|
||
|
|
ChaCha20 cipher at the top of its preference list. This usually indicates
|
||
|
|
a mobile client is in use. Equivalent to \fB\s-1SSL_OP_PRIORITIZE_CHACHA\s0\fR.
|
||
|
|
Only used by servers.
|
||
|
|
.Sp
|
||
|
|
\&\fBNoResumptionOnRenegotiation\fR: set
|
||
|
|
\&\fB\s-1SSL_OP_NO_SESSION_RESUMPTION_ON_RENEGOTIATION\s0\fR flag. Only used by servers.
|
||
|
|
.Sp
|
||
|
|
\&\fBNoRenegotiation\fR: disables all attempts at renegotiation in TLSv1.2 and
|
||
|
|
earlier, same as setting \fB\s-1SSL_OP_NO_RENEGOTIATION\s0\fR.
|
||
|
|
.Sp
|
||
|
|
\&\fBUnsafeLegacyRenegotiation\fR: permits the use of unsafe legacy renegotiation.
|
||
|
|
Equivalent to \fB\s-1SSL_OP_ALLOW_UNSAFE_LEGACY_RENEGOTIATION\s0\fR.
|
||
|
|
.Sp
|
||
|
|
\&\fBUnsafeLegacyServerConnect\fR: permits the use of unsafe legacy renegotiation
|
||
|
|
for OpenSSL clients only. Equivalent to \fB\s-1SSL_OP_LEGACY_SERVER_CONNECT\s0\fR.
|
||
|
|
Set by default.
|
||
|
|
.Sp
|
||
|
|
\&\fBEncryptThenMac\fR: use encrypt-then-mac extension, enabled by
|
||
|
|
default. Inverse of \fB\s-1SSL_OP_NO_ENCRYPT_THEN_MAC\s0\fR: that is,
|
||
|
|
\&\fB\-EncryptThenMac\fR is the same as setting \fB\s-1SSL_OP_NO_ENCRYPT_THEN_MAC\s0\fR.
|
||
|
|
.Sp
|
||
|
|
\&\fBAllowNoDHEKEX\fR: In TLSv1.3 allow a non\-(ec)dhe based key exchange mode on
|
||
|
|
resumption. This means that there will be no forward secrecy for the resumed
|
||
|
|
session. Equivalent to \fB\s-1SSL_OP_ALLOW_NO_DHE_KEX\s0\fR.
|
||
|
|
.Sp
|
||
|
|
\&\fBMiddleboxCompat\fR: If set then dummy Change Cipher Spec (\s-1CCS\s0) messages are sent
|
||
|
|
in TLSv1.3. This has the effect of making TLSv1.3 look more like TLSv1.2 so that
|
||
|
|
middleboxes that do not understand TLSv1.3 will not drop the connection. This
|
||
|
|
option is set by default. A future version of OpenSSL may not set this by
|
||
|
|
default. Equivalent to \fB\s-1SSL_OP_ENABLE_MIDDLEBOX_COMPAT\s0\fR.
|
||
|
|
.Sp
|
||
|
|
\&\fBAntiReplay\fR: If set then OpenSSL will automatically detect if a session ticket
|
||
|
|
has been used more than once, TLSv1.3 has been negotiated, and early data is
|
||
|
|
enabled on the server. A full handshake is forced if a session ticket is used a
|
||
|
|
second or subsequent time. This option is set by default and is only used by
|
||
|
|
servers. Anti-replay measures are required to comply with the TLSv1.3
|
||
|
|
specification. Some applications may be able to mitigate the replay risks in
|
||
|
|
other ways and in such cases the built-in OpenSSL functionality is not required.
|
||
|
|
Disabling anti-replay is equivalent to setting \fB\s-1SSL_OP_NO_ANTI_REPLAY\s0\fR.
|
||
|
|
.IP "\fBVerifyMode\fR" 4
|
||
|
|
.IX Item "VerifyMode"
|
||
|
|
The \fBvalue\fR argument is a comma separated list of flags to set.
|
||
|
|
.Sp
|
||
|
|
\&\fBPeer\fR enables peer verification: for clients only.
|
||
|
|
.Sp
|
||
|
|
\&\fBRequest\fR requests but does not require a certificate from the client.
|
||
|
|
Servers only.
|
||
|
|
.Sp
|
||
|
|
\&\fBRequire\fR requests and requires a certificate from the client: an error
|
||
|
|
occurs if the client does not present a certificate. Servers only.
|
||
|
|
.Sp
|
||
|
|
\&\fBOnce\fR requests a certificate from a client only on the initial connection:
|
||
|
|
not when renegotiating. Servers only.
|
||
|
|
.Sp
|
||
|
|
\&\fBRequestPostHandshake\fR configures the connection to support requests but does
|
||
|
|
not require a certificate from the client post-handshake. A certificate will
|
||
|
|
not be requested during the initial handshake. The server application must
|
||
|
|
provide a mechanism to request a certificate post-handshake. Servers only.
|
||
|
|
TLSv1.3 only.
|
||
|
|
.Sp
|
||
|
|
\&\fBRequiresPostHandshake\fR configures the connection to support requests and
|
||
|
|
requires a certificate from the client post-handshake: an error occurs if the
|
||
|
|
client does not present a certificate. A certificate will not be requested
|
||
|
|
during the initial handshake. The server application must provide a mechanism
|
||
|
|
to request a certificate post-handshake. Servers only. TLSv1.3 only.
|
||
|
|
.IP "\fBClientCAFile\fR, \fBClientCAPath\fR" 4
|
||
|
|
.IX Item "ClientCAFile, ClientCAPath"
|
||
|
|
A file or directory of certificates in \s-1PEM\s0 format whose names are used as the
|
||
|
|
set of acceptable names for client CAs. Servers only. This option is only
|
||
|
|
supported if certificate operations are permitted.
|
||
|
|
.SH "SUPPORTED COMMAND TYPES"
|
||
|
|
.IX Header "SUPPORTED COMMAND TYPES"
|
||
|
|
The function \fBSSL_CONF_cmd_value_type()\fR currently returns one of the following
|
||
|
|
types:
|
||
|
|
.IP "\fB\s-1SSL_CONF_TYPE_UNKNOWN\s0\fR" 4
|
||
|
|
.IX Item "SSL_CONF_TYPE_UNKNOWN"
|
||
|
|
The \fBcmd\fR string is unrecognised, this return value can be use to flag
|
||
|
|
syntax errors.
|
||
|
|
.IP "\fB\s-1SSL_CONF_TYPE_STRING\s0\fR" 4
|
||
|
|
.IX Item "SSL_CONF_TYPE_STRING"
|
||
|
|
The value is a string without any specific structure.
|
||
|
|
.IP "\fB\s-1SSL_CONF_TYPE_FILE\s0\fR" 4
|
||
|
|
.IX Item "SSL_CONF_TYPE_FILE"
|
||
|
|
The value is a file name.
|
||
|
|
.IP "\fB\s-1SSL_CONF_TYPE_DIR\s0\fR" 4
|
||
|
|
.IX Item "SSL_CONF_TYPE_DIR"
|
||
|
|
The value is a directory name.
|
||
|
|
.IP "\fB\s-1SSL_CONF_TYPE_NONE\s0\fR" 4
|
||
|
|
.IX Item "SSL_CONF_TYPE_NONE"
|
||
|
|
The value string is not used e.g. a command line option which doesn't take an
|
||
|
|
argument.
|
||
|
|
.SH "NOTES"
|
||
|
|
.IX Header "NOTES"
|
||
|
|
The order of operations is significant. This can be used to set either defaults
|
||
|
|
or values which cannot be overridden. For example if an application calls:
|
||
|
|
.PP
|
||
|
|
.Vb 2
|
||
|
|
\& SSL_CONF_cmd(ctx, "Protocol", "\-SSLv3");
|
||
|
|
\& SSL_CONF_cmd(ctx, userparam, uservalue);
|
||
|
|
.Ve
|
||
|
|
.PP
|
||
|
|
it will disable SSLv3 support by default but the user can override it. If
|
||
|
|
however the call sequence is:
|
||
|
|
.PP
|
||
|
|
.Vb 2
|
||
|
|
\& SSL_CONF_cmd(ctx, userparam, uservalue);
|
||
|
|
\& SSL_CONF_cmd(ctx, "Protocol", "\-SSLv3");
|
||
|
|
.Ve
|
||
|
|
.PP
|
||
|
|
SSLv3 is \fBalways\fR disabled and attempt to override this by the user are
|
||
|
|
ignored.
|
||
|
|
.PP
|
||
|
|
By checking the return code of \fBSSL_CONF_cmd()\fR it is possible to query if a
|
||
|
|
given \fBcmd\fR is recognised, this is useful if \fBSSL_CONF_cmd()\fR values are
|
||
|
|
mixed with additional application specific operations.
|
||
|
|
.PP
|
||
|
|
For example an application might call \fBSSL_CONF_cmd()\fR and if it returns
|
||
|
|
\&\-2 (unrecognised command) continue with processing of application specific
|
||
|
|
commands.
|
||
|
|
.PP
|
||
|
|
Applications can also use \fBSSL_CONF_cmd()\fR to process command lines though the
|
||
|
|
utility function \fBSSL_CONF_cmd_argv()\fR is normally used instead. One way
|
||
|
|
to do this is to set the prefix to an appropriate value using
|
||
|
|
\&\fBSSL_CONF_CTX_set1_prefix()\fR, pass the current argument to \fBcmd\fR and the
|
||
|
|
following argument to \fBvalue\fR (which may be \s-1NULL\s0).
|
||
|
|
.PP
|
||
|
|
In this case if the return value is positive then it is used to skip that
|
||
|
|
number of arguments as they have been processed by \fBSSL_CONF_cmd()\fR. If \-2 is
|
||
|
|
returned then \fBcmd\fR is not recognised and application specific arguments
|
||
|
|
can be checked instead. If \-3 is returned a required argument is missing
|
||
|
|
and an error is indicated. If 0 is returned some other error occurred and
|
||
|
|
this can be reported back to the user.
|
||
|
|
.PP
|
||
|
|
The function \fBSSL_CONF_cmd_value_type()\fR can be used by applications to
|
||
|
|
check for the existence of a command or to perform additional syntax
|
||
|
|
checking or translation of the command value. For example if the return
|
||
|
|
value is \fB\s-1SSL_CONF_TYPE_FILE\s0\fR an application could translate a relative
|
||
|
|
pathname to an absolute pathname.
|
||
|
|
.SH "RETURN VALUES"
|
||
|
|
.IX Header "RETURN VALUES"
|
||
|
|
\&\fBSSL_CONF_cmd()\fR returns 1 if the value of \fBcmd\fR is recognised and \fBvalue\fR is
|
||
|
|
\&\fB\s-1NOT\s0\fR used and 2 if both \fBcmd\fR and \fBvalue\fR are used. In other words it
|
||
|
|
returns the number of arguments processed. This is useful when processing
|
||
|
|
command lines.
|
||
|
|
.PP
|
||
|
|
A return value of \-2 means \fBcmd\fR is not recognised.
|
||
|
|
.PP
|
||
|
|
A return value of \-3 means \fBcmd\fR is recognised and the command requires a
|
||
|
|
value but \fBvalue\fR is \s-1NULL.\s0
|
||
|
|
.PP
|
||
|
|
A return code of 0 indicates that both \fBcmd\fR and \fBvalue\fR are valid but an
|
||
|
|
error occurred attempting to perform the operation: for example due to an
|
||
|
|
error in the syntax of \fBvalue\fR in this case the error queue may provide
|
||
|
|
additional information.
|
||
|
|
.SH "EXAMPLES"
|
||
|
|
.IX Header "EXAMPLES"
|
||
|
|
Set supported signature algorithms:
|
||
|
|
.PP
|
||
|
|
.Vb 1
|
||
|
|
\& SSL_CONF_cmd(ctx, "SignatureAlgorithms", "ECDSA+SHA256:RSA+SHA256:DSA+SHA256");
|
||
|
|
.Ve
|
||
|
|
.PP
|
||
|
|
There are various ways to select the supported protocols.
|
||
|
|
.PP
|
||
|
|
This set the minimum protocol version to TLSv1, and so disables SSLv3.
|
||
|
|
This is the recommended way to disable protocols.
|
||
|
|
.PP
|
||
|
|
.Vb 1
|
||
|
|
\& SSL_CONF_cmd(ctx, "MinProtocol", "TLSv1");
|
||
|
|
.Ve
|
||
|
|
.PP
|
||
|
|
The following also disables SSLv3:
|
||
|
|
.PP
|
||
|
|
.Vb 1
|
||
|
|
\& SSL_CONF_cmd(ctx, "Protocol", "\-SSLv3");
|
||
|
|
.Ve
|
||
|
|
.PP
|
||
|
|
The following will first enable all protocols, and then disable
|
||
|
|
SSLv3.
|
||
|
|
If no protocol versions were disabled before this has the same effect as
|
||
|
|
\&\*(L"\-SSLv3\*(R", but if some versions were disables this will re-enable them before
|
||
|
|
disabling SSLv3.
|
||
|
|
.PP
|
||
|
|
.Vb 1
|
||
|
|
\& SSL_CONF_cmd(ctx, "Protocol", "ALL,\-SSLv3");
|
||
|
|
.Ve
|
||
|
|
.PP
|
||
|
|
Only enable TLSv1.2:
|
||
|
|
.PP
|
||
|
|
.Vb 2
|
||
|
|
\& SSL_CONF_cmd(ctx, "MinProtocol", "TLSv1.2");
|
||
|
|
\& SSL_CONF_cmd(ctx, "MaxProtocol", "TLSv1.2");
|
||
|
|
.Ve
|
||
|
|
.PP
|
||
|
|
This also only enables TLSv1.2:
|
||
|
|
.PP
|
||
|
|
.Vb 1
|
||
|
|
\& SSL_CONF_cmd(ctx, "Protocol", "\-ALL,TLSv1.2");
|
||
|
|
.Ve
|
||
|
|
.PP
|
||
|
|
Disable \s-1TLS\s0 session tickets:
|
||
|
|
.PP
|
||
|
|
.Vb 1
|
||
|
|
\& SSL_CONF_cmd(ctx, "Options", "\-SessionTicket");
|
||
|
|
.Ve
|
||
|
|
.PP
|
||
|
|
Enable compression:
|
||
|
|
.PP
|
||
|
|
.Vb 1
|
||
|
|
\& SSL_CONF_cmd(ctx, "Options", "Compression");
|
||
|
|
.Ve
|
||
|
|
.PP
|
||
|
|
Set supported curves to P\-256, P\-384:
|
||
|
|
.PP
|
||
|
|
.Vb 1
|
||
|
|
\& SSL_CONF_cmd(ctx, "Curves", "P\-256:P\-384");
|
||
|
|
.Ve
|
||
|
|
.SH "SEE ALSO"
|
||
|
|
.IX Header "SEE ALSO"
|
||
|
|
\&\fBSSL_CONF_CTX_new\fR\|(3),
|
||
|
|
\&\fBSSL_CONF_CTX_set_flags\fR\|(3),
|
||
|
|
\&\fBSSL_CONF_CTX_set1_prefix\fR\|(3),
|
||
|
|
\&\fBSSL_CONF_CTX_set_ssl_ctx\fR\|(3),
|
||
|
|
\&\fBSSL_CONF_cmd_argv\fR\|(3),
|
||
|
|
\&\fBSSL_CTX_set_options\fR\|(3)
|
||
|
|
.SH "HISTORY"
|
||
|
|
.IX Header "HISTORY"
|
||
|
|
The \fBSSL_CONF_cmd()\fR function was added in OpenSSL 1.0.2.
|
||
|
|
.PP
|
||
|
|
The \fB\s-1SSL_OP_NO_SSL2\s0\fR option doesn't have effect since 1.1.0, but the macro
|
||
|
|
is retained for backwards compatibility.
|
||
|
|
.PP
|
||
|
|
The \fB\s-1SSL_CONF_TYPE_NONE\s0\fR was added in OpenSSL 1.1.0. In earlier versions of
|
||
|
|
OpenSSL passing a command which didn't take an argument would return
|
||
|
|
\&\fB\s-1SSL_CONF_TYPE_UNKNOWN\s0\fR.
|
||
|
|
.PP
|
||
|
|
\&\fBMinProtocol\fR and \fBMaxProtocol\fR where added in OpenSSL 1.1.0.
|
||
|
|
.PP
|
||
|
|
\&\fBAllowNoDHEKEX\fR and \fBPrioritizeChaCha\fR were added in OpenSSL 1.1.1.
|
||
|
|
.SH "COPYRIGHT"
|
||
|
|
.IX Header "COPYRIGHT"
|
||
|
|
Copyright 2012\-2019 The OpenSSL Project Authors. All Rights Reserved.
|
||
|
|
.PP
|
||
|
|
Licensed under the OpenSSL license (the \*(L"License\*(R"). You may not use
|
||
|
|
this file except in compliance with the License. You can obtain a copy
|
||
|
|
in the file \s-1LICENSE\s0 in the source distribution or at
|
||
|
|
<https://www.openssl.org/source/license.html>.
|