diff options
author | Dr. David von Oheimb <David.von.Oheimb@siemens.com> | 2021-02-16 11:17:07 +0100 |
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committer | Dr. David von Oheimb <dev@ddvo.net> | 2021-06-26 15:38:40 +0200 |
commit | 4acda8635ed55ddf831d1bb3dc6086054f01cc61 (patch) | |
tree | f366f096ef49946d775a738463cc7d89f12858e0 /doc | |
parent | 426005eea5afd64bb76006f0fda69502ab3e008d (diff) |
DOC: Clarify the role of EKUs including defaults for TLS client and server use
Reviewed-by: Paul Dale <pauli@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/14199)
Diffstat (limited to 'doc')
-rw-r--r-- | doc/man1/openssl-verification-options.pod | 27 | ||||
-rw-r--r-- | doc/man1/openssl-x509.pod.in | 10 | ||||
-rw-r--r-- | doc/man3/SSL_CTX_new.pod | 28 | ||||
-rw-r--r-- | doc/man3/SSL_CTX_set_verify.pod | 2 | ||||
-rw-r--r-- | doc/man3/SSL_new.pod | 2 | ||||
-rw-r--r-- | doc/man3/X509_STORE_CTX_new.pod | 5 | ||||
-rw-r--r-- | doc/man3/X509_VERIFY_PARAM_set_flags.pod | 2 | ||||
-rw-r--r-- | doc/man3/X509_check_purpose.pod | 3 | ||||
-rw-r--r-- | doc/man5/x509v3_config.pod | 18 |
9 files changed, 67 insertions, 30 deletions
diff --git a/doc/man1/openssl-verification-options.pod b/doc/man1/openssl-verification-options.pod index 1c91c77852..c634ccae15 100644 --- a/doc/man1/openssl-verification-options.pod +++ b/doc/man1/openssl-verification-options.pod @@ -151,10 +151,13 @@ The first step is to check that each certificate is well-formed. Part of these checks are enabled only if the B<-x509_strict> option is given. The second step is to check the extensions of every untrusted certificate -for consistency with the given purpose. -If the B<-purpose> option is not included then no such checks are done. -The target certificate must not have an EKU extension that is incompatible with -the given purpose, and all other certificates must be valid CA certificates. +for consistency with the supplied purpose. +If the B<-purpose> option is not given then no such checks are done +except for SSL/TLS connection setup, +where by default C<sslserver> or C<sslclient>, are checked. +The target or "leaf" certificate, as well as any other untrusted certificates, +must have extensions compatible with the specified purpose. +All certificates except the target or "leaf" must also be valid CA certificates. The precise extensions required are described in more detail in L<openssl-x509(1)/CERTIFICATE EXTENSIONS>. @@ -452,11 +455,17 @@ Set policy variable inhibit-policy-mapping (see RFC5280). =item B<-purpose> I<purpose> -The intended use for the certificate. If this option is not specified, this -command will not consider certificate purpose during chain verification. -Currently accepted uses are B<sslclient>, B<sslserver>, B<nssslserver>, -B<smimesign>, B<smimeencrypt>, B<crlsign>, B<ocsphelper>, B<timestampsign>, -and <any>. +The intended use for the certificate. +Currently defined purposes are C<sslclient>, C<sslserver>, C<nssslserver>, +C<smimesign>, C<smimeencrypt>, C<crlsign>, C<ocsphelper>, C<timestampsign>, +and C<any>. +If peer certificate verification is enabled, by default the TLS implementation +as well as the commands B<s_client> and B<s_server> check for consistency +with TLS server or TLS client use, respectively. + +While IETF RFC 5280 says that B<id-kp-serverAuth> and B<id-kp-clientAuth> +are only for WWW use, in practice they are used for all kinds of TLS clients +and servers, and this is what OpenSSL assumes as well. =item B<-verify_depth> I<num> diff --git a/doc/man1/openssl-x509.pod.in b/doc/man1/openssl-x509.pod.in index 0e073d6b05..9c77a216c2 100644 --- a/doc/man1/openssl-x509.pod.in +++ b/doc/man1/openssl-x509.pod.in @@ -551,10 +551,12 @@ Clears all the permitted or trusted uses of the certificate. =item B<-addtrust> I<arg> -Adds an allowed trust anchor purpose. -Any object name can be used here but currently only those -listed in L<openssl-verification-options(1)/Trust Anchors> are supported. -Other OpenSSL applications may define additional purposes. +Adds a trusted certificate use. +Any object name can be used here but currently only B<clientAuth>, +B<serverAuth>, B<emailProtection>, and B<anyExtendedKeyUsage> are defined. +As of OpenSSL 1.1.0, the last of these blocks all purposes when rejected or +enables all purposes when trusted. +Other OpenSSL applications may define additional uses. =item B<-clrreject> diff --git a/doc/man3/SSL_CTX_new.pod b/doc/man3/SSL_CTX_new.pod index 6bab45631f..61de1a6551 100644 --- a/doc/man3/SSL_CTX_new.pod +++ b/doc/man3/SSL_CTX_new.pod @@ -74,8 +74,11 @@ functions =head1 DESCRIPTION SSL_CTX_new_ex() creates a new B<SSL_CTX> object, which holds various -configuration and data relevant to TLS/SSL or DTLS session establishment. The -library context I<libctx> (see L<OSSL_LIB_CTX(3)>) is used to provide the +configuration and data relevant to SSL/TLS or DTLS session establishment. +These are later inherited by the B<SSL> object representing an active session. +The I<method> parameter specifies whether the context will be used for the +client or server side or both - for details see the L</NOTES> below. +The library context I<libctx> (see L<OSSL_LIB_CTX(3)>) is used to provide the cryptographic algorithms needed for the session. Any cryptographic algorithms that are used by any B<SSL> objects created from this B<SSL_CTX> will be fetched from the I<libctx> using the property query string I<propq> (see @@ -97,10 +100,21 @@ provide serialization of access for these cases. =head1 NOTES +On session estabilishment, by default, no peer credentials verification is done. +This must be explicitly requested, typically using L<SSL_CTX_set_verify(3)>. +For verifying peer certificates many options can be set using various functions +such as L<SSL_CTX_load_verify_locations(3)> and L<SSL_CTX_set1_param(3)>. +The L<X509_VERIFY_PARAM_set_purpose(3)> function can be used, also in conjunction +with L<SSL_CTX_get0_param(3)>, to set the intended purpose of the session. +The default is B<X509_PURPOSE_SSL_SERVER> on the client side +and B<X509_PURPOSE_SSL_CLIENT> on the server side. + The SSL_CTX object uses I<method> as the connection method. -The methods exist in a generic type (for client and server use), a server only -type, and a client only type. -B<method> can be one of the following types: +Three method variants are available: a generic method (for either client or +server use), a server-only method, and a client-only method. + +The I<method> parameter of SSL_CTX_new_ex() and SSL_CTX_new() +can be one of the following: =over 4 @@ -214,7 +228,9 @@ SSL_CTX_up_ref() returns 1 for success and 0 for failure. =head1 SEE ALSO -L<SSL_CTX_set_options(3)>, L<SSL_CTX_free(3)>, L<SSL_accept(3)>, +L<SSL_CTX_set_options(3)>, L<SSL_CTX_free(3)>, +SSL_CTX_set_verify(3), L<SSL_CTX_set1_param(3)>, L<SSL_CTX_get0_param(3)>, +L<SSL_connect(3)>, L<SSL_accept(3)>, L<SSL_CTX_set_min_proto_version(3)>, L<ssl(7)>, L<SSL_set_connect_state(3)> =head1 HISTORY diff --git a/doc/man3/SSL_CTX_set_verify.pod b/doc/man3/SSL_CTX_set_verify.pod index b72227c924..5e3ebef8e6 100644 --- a/doc/man3/SSL_CTX_set_verify.pod +++ b/doc/man3/SSL_CTX_set_verify.pod @@ -9,7 +9,7 @@ SSL_verify_cb, SSL_verify_client_post_handshake, SSL_set_post_handshake_auth, SSL_CTX_set_post_handshake_auth -- set peer certificate verification parameters +- set various SSL/TLS parameters for peer certificate verification =head1 SYNOPSIS diff --git a/doc/man3/SSL_new.pod b/doc/man3/SSL_new.pod index c7c5758cb1..02cbd036b5 100644 --- a/doc/man3/SSL_new.pod +++ b/doc/man3/SSL_new.pod @@ -61,7 +61,7 @@ L<SSL_set_tmp_dh_callback(3)>, or L<SSL_set_dh_auto(3)> L<SSL_set_min_proto_version(3)> or L<SSL_set_max_proto_version(3)> (Note: Only from OpenSSL 1.1.1h and above) -=item any Verify mode, callback or depth set via L<SSL_set_verify(3)> or +=item any verify mode, callback or depth set via L<SSL_set_verify(3)> or L<SSL_set_verify_depth(3)> or any configured X509 verification parameters =item any msg callback or info callback set via L<SSL_set_msg_callback(3)> or diff --git a/doc/man3/X509_STORE_CTX_new.pod b/doc/man3/X509_STORE_CTX_new.pod index b982dc9c7e..56a36bfecd 100644 --- a/doc/man3/X509_STORE_CTX_new.pod +++ b/doc/man3/X509_STORE_CTX_new.pod @@ -138,7 +138,10 @@ and so it should not be free'd by the caller. X509_STORE_CTX_set_default() looks up and sets the default verification method to I<name>. This uses the function X509_VERIFY_PARAM_lookup() to -find an appropriate set of parameters from I<name>. +find an appropriate set of parameters from the purpose identifier I<name>. +Currently defined purposes are C<sslclient>, C<sslserver>, C<nssslserver>, +C<smimesign>, C<smimeencrypt>, C<crlsign>, C<ocsphelper>, C<timestampsign>, +and C<any>. X509_STORE_CTX_set_verify() provides the capability for overriding the default verify function. This function is responsible for verifying chain signatures and diff --git a/doc/man3/X509_VERIFY_PARAM_set_flags.pod b/doc/man3/X509_VERIFY_PARAM_set_flags.pod index 2041176d4f..1213627be7 100644 --- a/doc/man3/X509_VERIFY_PARAM_set_flags.pod +++ b/doc/man3/X509_VERIFY_PARAM_set_flags.pod @@ -89,7 +89,7 @@ X509_VERIFY_PARAM_clear_flags() clears the flags B<flags> in B<param>. X509_VERIFY_PARAM_set_purpose() sets the verification purpose in B<param> to B<purpose>. This determines the acceptable purpose of the certificate -chain, for example SSL client or SSL server. +chain, for example B<X509_PURPOSE_SSL_CLIENT>. X509_VERIFY_PARAM_set_trust() sets the trust setting in B<param> to B<trust>. diff --git a/doc/man3/X509_check_purpose.pod b/doc/man3/X509_check_purpose.pod index e0f1353842..619ed7831a 100644 --- a/doc/man3/X509_check_purpose.pod +++ b/doc/man3/X509_check_purpose.pod @@ -29,6 +29,9 @@ Below are the potential ID's that can be checked: # define X509_PURPOSE_OCSP_HELPER 8 # define X509_PURPOSE_TIMESTAMP_SIGN 9 +The checks performed take into account the X.509 extensions +keyUsage, extendedKeyUsage, and basicConstraints. + =head1 RETURN VALUES For non-CA checks diff --git a/doc/man5/x509v3_config.pod b/doc/man5/x509v3_config.pod index f8bc6d0ff1..fb7c3aaff7 100644 --- a/doc/man5/x509v3_config.pod +++ b/doc/man5/x509v3_config.pod @@ -142,15 +142,15 @@ Examples: =head2 Extended Key Usage This extension consists of a list of values indicating purposes for which -the certificate public key can be used for, Each value can be either a -short text name or an OID. +the certificate public key can be used. +Each value can be either a short text name or an OID. The following text names, and their intended meaning, are known: - Value Meaning - ----- ------- - serverAuth SSL/TLS Web Server Authentication - clientAuth SSL/TLS Web Client Authentication - codeSigning Code signing + Value Meaning according to RFC 5280 etc. + ----- ---------------------------------- + serverAuth SSL/TLS WWW Server Authentication + clientAuth SSL/TLS WWW Client Authentication + codeSigning Code Signing emailProtection E-mail Protection (S/MIME) timeStamping Trusted Timestamping OCSPSigning OCSP Signing @@ -160,6 +160,10 @@ The following text names, and their intended meaning, are known: msCTLSign Microsoft Trust List Signing msEFS Microsoft Encrypted File System +While IETF RFC 5280 says that B<id-kp-serverAuth> and B<id-kp-clientAuth> +are only for WWW use, in practice they are used for all kinds of TLS clients +and servers, and this is what OpenSSL assumes as well. + Examples: extendedKeyUsage = critical, codeSigning, 1.2.3.4 |