Apache Module mod_ssl

Available Languages: en

+ + + +

Description:	Strong cryptography using the Secure Sockets +Layer (SSL) and Transport Layer Security (TLS) protocols
Status:	Extension
Module Identifier:	ssl_module
Source File:	mod_ssl.c

Summary

+ +

This module provides SSL v2/v3 and TLS v1 support for the Apache +HTTP Server. It was contributed by Ralf S. Engeschall based on his +mod_ssl project and originally derived from work by Ben Laurie.

+ +

This module relies on OpenSSL +to provide the cryptography engine.

+ +

Further details, discussion, and examples are provided in the +SSL documentation.

+ +

Environment Variables

+ +

This module provides a lot of SSL information as additional environment +variables to the SSI and CGI namespace. The generated variables are listed in +the table below. For backward compatibility the information can +be made available under different names, too. Look in the Compatibility chapter for details on the +compatibility variables.

+ + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + +

Variable Name:	Value Type:	Description:
`HTTPS`	flag	HTTPS is being used.
`SSL_PROTOCOL`	string	The SSL protocol version (SSLv2, SSLv3, TLSv1)
`SSL_SESSION_ID`	string	The hex-encoded SSL session id
`SSL_CIPHER`	string	The cipher specification name
`SSL_CIPHER_EXPORT`	string	`true` if cipher is an export cipher
`SSL_CIPHER_USEKEYSIZE`	number	Number of cipher bits (actually used)
`SSL_CIPHER_ALGKEYSIZE`	number	Number of cipher bits (possible)
`SSL_VERSION_INTERFACE`	string	The mod_ssl program version
`SSL_VERSION_LIBRARY`	string	The OpenSSL program version
`SSL_CLIENT_M_VERSION`	string	The version of the client certificate
`SSL_CLIENT_M_SERIAL`	string	The serial of the client certificate
`SSL_CLIENT_S_DN`	string	Subject DN in client's certificate
`SSL_CLIENT_S_DN_`x509	string	Component of client's Subject DN
`SSL_CLIENT_I_DN`	string	Issuer DN of client's certificate
`SSL_CLIENT_I_DN_`x509	string	Component of client's Issuer DN
`SSL_CLIENT_V_START`	string	Validity of client's certificate (start time)
`SSL_CLIENT_V_END`	string	Validity of client's certificate (end time)
`SSL_CLIENT_A_SIG`	string	Algorithm used for the signature of client's certificate
`SSL_CLIENT_A_KEY`	string	Algorithm used for the public key of client's certificate
`SSL_CLIENT_CERT`	string	PEM-encoded client certificate
`SSL_CLIENT_CERT_CHAIN`n	string	PEM-encoded certificates in client certificate chain
`SSL_CLIENT_VERIFY`	string	`NONE`, `SUCCESS`, `GENEROUS` or `FAILED:`reason
`SSL_SERVER_M_VERSION`	string	The version of the server certificate
`SSL_SERVER_M_SERIAL`	string	The serial of the server certificate
`SSL_SERVER_S_DN`	string	Subject DN in server's certificate
`SSL_SERVER_S_DN_`x509	string	Component of server's Subject DN
`SSL_SERVER_I_DN`	string	Issuer DN of server's certificate
`SSL_SERVER_I_DN_`x509	string	Component of server's Issuer DN
`SSL_SERVER_V_START`	string	Validity of server's certificate (start time)
`SSL_SERVER_V_END`	string	Validity of server's certificate (end time)
`SSL_SERVER_A_SIG`	string	Algorithm used for the signature of server's certificate
`SSL_SERVER_A_KEY`	string	Algorithm used for the public key of server's certificate
`SSL_SERVER_CERT`	string	PEM-encoded server certificate

[ where x509 is a component of a X.509 DN: + C,ST,L,O,OU,CN,T,I,G,S,D,UID,Email ]

Custom Log Formats

+ +

When mod_ssl is built into Apache or at least +loaded (under DSO situation) additional functions exist for the Custom Log Format of +mod_log_config. First there is an +additional ``%{varname}x'' +eXtension format function which can be used to expand any variables +provided by any module, especially those provided by mod_ssl which can +you find in the above table.

+For backward compatibility there is additionally a special +``%{name}c'' cryptography format function +provided. Information about this function is provided in the Compatibility chapter.

+Example:

+CustomLog logs/ssl_request_log \ + "%t %h %{SSL_PROTOCOL}x %{SSL_CIPHER}x \"%r\" %b" +

SSLCACertificateFile Directive

+ + + + + + +

Description:	File of concatenated PEM-encoded CA Certificates +for Client Auth
Syntax:	`SSLCACertificateFile file-path`
Context:	server config, virtual host
Status:	Extension
Module:	mod_ssl

+This directive sets the all-in-one file where you can assemble the +Certificates of Certification Authorities (CA) whose clients you deal +with. These are used for Client Authentication. Such a file is simply the +concatenation of the various PEM-encoded Certificate files, in order of +preference. This can be used alternatively and/or additionally to +SSLCACertificatePath.

Example

+SSLCACertificateFile /usr/local/apache2/conf/ssl.crt/ca-bundle-client.crt +

+ +

SSLCACertificatePath Directive

+ + + + + + +

Description:	Directory of PEM-encoded CA Certificates for +Client Auth
Syntax:	`SSLCACertificatePath directory-path`
Context:	server config, virtual host
Status:	Extension
Module:	mod_ssl

+This directive sets the directory where you keep the Certificates of +Certification Authorities (CAs) whose clients you deal with. These are used to +verify the client certificate on Client Authentication.

+The files in this directory have to be PEM-encoded and are accessed through +hash filenames. So usually you can't just place the Certificate files +there: you also have to create symbolic links named +hash-value.N. And you should always make sure this directory +contains the appropriate symbolic links.

Example

+SSLCACertificatePath /usr/local/apache2/conf/ssl.crt/ +

+ +

SSLCARevocationFile Directive

+ + + + + + +

Description:	File of concatenated PEM-encoded CA CRLs for +Client Auth
Syntax:	`SSLCARevocationFile file-path`
Context:	server config, virtual host
Status:	Extension
Module:	mod_ssl

+This directive sets the all-in-one file where you can +assemble the Certificate Revocation Lists (CRL) of Certification +Authorities (CA) whose clients you deal with. These are used +for Client Authentication. Such a file is simply the concatenation of +the various PEM-encoded CRL files, in order of preference. This can be +used alternatively and/or additionally to SSLCARevocationPath.

Example

+SSLCARevocationFile /usr/local/apache2/conf/ssl.crl/ca-bundle-client.crl +

+ +

SSLCARevocationPath Directive

+ + + + + + +

Description:	Directory of PEM-encoded CA CRLs for +Client Auth
Syntax:	`SSLCARevocationPath directory-path`
Context:	server config, virtual host
Status:	Extension
Module:	mod_ssl

+This directive sets the directory where you keep the Certificate Revocation +Lists (CRL) of Certification Authorities (CAs) whose clients you deal with. +These are used to revoke the client certificate on Client Authentication.

+The files in this directory have to be PEM-encoded and are accessed through +hash filenames. So usually you have not only to place the CRL files there. +Additionally you have to create symbolic links named +hash-value.rN. And you should always make sure this directory +contains the appropriate symbolic links.

Example

+SSLCARevocationPath /usr/local/apache2/conf/ssl.crl/ +

+ +

SSLCertificateChainFile Directive

+ + + + + + +

Description:	File of PEM-encoded Server CA Certificates
Syntax:	`SSLCertificateChainFile file-path`
Context:	server config, virtual host
Status:	Extension
Module:	mod_ssl

+This directive sets the optional all-in-one file where you can +assemble the certificates of Certification Authorities (CA) which form the +certificate chain of the server certificate. This starts with the issuing CA +certificate of of the server certificate and can range up to the root CA +certificate. Such a file is simply the concatenation of the various +PEM-encoded CA Certificate files, usually in certificate chain order.

+This should be used alternatively and/or additionally to SSLCACertificatePath for explicitly +constructing the server certificate chain which is sent to the browser +in addition to the server certificate. It is especially useful to +avoid conflicts with CA certificates when using client +authentication. Because although placing a CA certificate of the +server certificate chain into SSLCACertificatePath has the same effect +for the certificate chain construction, it has the side-effect that +client certificates issued by this same CA certificate are also +accepted on client authentication. That's usually not one expect.

+But be careful: Providing the certificate chain works only if you are using a +single (either RSA or DSA) based server certificate. If you are +using a coupled RSA+DSA certificate pair, this will work only if actually both +certificates use the same certificate chain. Else the browsers will be +confused in this situation.

Example

+SSLCertificateChainFile /usr/local/apache2/conf/ssl.crt/ca.crt +

+ +

SSLCertificateFile Directive

+ + + + + + +

Description:	Server PEM-encoded X.509 Certificate file
Syntax:	`SSLCertificateFile file-path`
Context:	server config, virtual host
Status:	Extension
Module:	mod_ssl

+This directive points to the PEM-encoded Certificate file for the server and +optionally also to the corresponding RSA or DSA Private Key file for it +(contained in the same file). If the contained Private Key is encrypted the +Pass Phrase dialog is forced at startup time. This directive can be used up to +two times (referencing different filenames) when both a RSA and a DSA based +server certificate is used in parallel.

Example

+SSLCertificateFile /usr/local/apache2/conf/ssl.crt/server.crt +

+ +

SSLCertificateKeyFile Directive

+ + + + + + +

Description:	Server PEM-encoded Private Key file
Syntax:	`SSLCertificateKeyFile file-path`
Context:	server config, virtual host
Status:	Extension
Module:	mod_ssl

+This directive points to the PEM-encoded Private Key file for the +server. If the Private Key is not combined with the Certificate in the +SSLCertificateFile, use this additional directive to +point to the file with the stand-alone Private Key. When +SSLCertificateFile is used and the file +contains both the Certificate and the Private Key this directive need +not be used. But we strongly discourage this practice. Instead we +recommend you to separate the Certificate and the Private Key. If the +contained Private Key is encrypted, the Pass Phrase dialog is forced +at startup time. This directive can be used up to two times +(referencing different filenames) when both a RSA and a DSA based +private key is used in parallel.

Example

+SSLCertificateKeyFile /usr/local/apache2/conf/ssl.key/server.key +

+ +

SSLCipherSuite Directive

+ + + + + + + + +

Description:	Cipher Suite available for negotiation in SSL +handshake
Syntax:	`SSLCipherSuite cipher-spec`
Default:	`SSLCipherSuite ALL:!ADH:RC4+RSA:+HIGH:+MEDIUM:+LOW:+SSLv2:+EXP`
Context:	server config, virtual host, directory, .htaccess
Override:	AuthConfig
Status:	Extension
Module:	mod_ssl

+This complex directive uses a colon-separated cipher-spec string +consisting of OpenSSL cipher specifications to configure the Cipher Suite the +client is permitted to negotiate in the SSL handshake phase. Notice that this +directive can be used both in per-server and per-directory context. In +per-server context it applies to the standard SSL handshake when a connection +is established. In per-directory context it forces a SSL renegotation with the +reconfigured Cipher Suite after the HTTP request was read but before the HTTP +response is sent.

+An SSL cipher specification in cipher-spec is composed of 4 major +attributes plus a few extra minor ones:

Key Exchange Algorithm:
+ RSA or Diffie-Hellman variants. +
Authentication Algorithm:
+ RSA, Diffie-Hellman, DSS or none. +
Cipher/Encryption Algorithm:
+ DES, Triple-DES, RC4, RC2, IDEA or none. +
MAC Digest Algorithm:
+ MD5, SHA or SHA1. +

An SSL cipher can also be an export cipher and is either a SSLv2 or SSLv3/TLSv1 +cipher (here TLSv1 is equivalent to SSLv3). To specify which ciphers to use, +one can either specify all the Ciphers, one at a time, or use aliases to +specify the preference and order for the ciphers (see Table +1).

+ + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + +

Tag	Description
Key Exchange Algorithm:
`kRSA`	RSA key exchange
`kDHr`	Diffie-Hellman key exchange with RSA key
`kDHd`	Diffie-Hellman key exchange with DSA key
`kEDH`	Ephemeral (temp.key) Diffie-Hellman key exchange (no cert)
Authentication Algorithm:
`aNULL`	No authentication
`aRSA`	RSA authentication
`aDSS`	DSS authentication
`aDH`	Diffie-Hellman authentication
Cipher Encoding Algorithm:
`eNULL`	No encoding
`DES`	DES encoding
`3DES`	Triple-DES encoding
`RC4`	RC4 encoding
`RC2`	RC2 encoding
`IDEA`	IDEA encoding
MAC Digest Algorithm:
`MD5`	MD5 hash function
`SHA1`	SHA1 hash function
`SHA`	SHA hash function
Aliases:
`SSLv2`	all SSL version 2.0 ciphers
`SSLv3`	all SSL version 3.0 ciphers
`TLSv1`	all TLS version 1.0 ciphers
`EXP`	all export ciphers
`EXPORT40`	all 40-bit export ciphers only
`EXPORT56`	all 56-bit export ciphers only
`LOW`	all low strength ciphers (no export, single DES)
`MEDIUM`	all ciphers with 128 bit encryption
`HIGH`	all ciphers using Triple-DES
`RSA`	all ciphers using RSA key exchange
`DH`	all ciphers using Diffie-Hellman key exchange
`EDH`	all ciphers using Ephemeral Diffie-Hellman key exchange
`ADH`	all ciphers using Anonymous Diffie-Hellman key exchange
`DSS`	all ciphers using DSS authentication
`NULL`	all ciphers using no encryption

+Now where this becomes interesting is that these can be put together +to specify the order and ciphers you wish to use. To speed this up +there are also aliases (SSLv2, SSLv3, TLSv1, EXP, LOW, MEDIUM, +HIGH) for certain groups of ciphers. These tags can be joined +together with prefixes to form the cipher-spec. Available +prefixes are:

none: add cipher to list
+: add ciphers to list and pull them to current location in list
-: remove cipher from list (can be added later again)
!: kill cipher from list completely (can not be added later again)

A simpler way to look at all of this is to use the ``openssl ciphers +-v'' command which provides a nice way to successively create the +correct cipher-spec string. The default cipher-spec string +is ``ALL:!ADH:RC4+RSA:+HIGH:+MEDIUM:+LOW:+SSLv2:+EXP'' which +means the following: first, remove from consideration any ciphers that do not +authenticate, i.e. for SSL only the Anonymous Diffie-Hellman ciphers. Next, +use ciphers using RC4 and RSA. Next include the high, medium and then the low +security ciphers. Finally pull all SSLv2 and export ciphers to the +end of the list.

+$ openssl ciphers -v 'ALL:!ADH:RC4+RSA:+HIGH:+MEDIUM:+LOW:+SSLv2:+EXP'
+NULL-SHA                SSLv3 Kx=RSA      Au=RSA  Enc=None      Mac=SHA1
+NULL-MD5                SSLv3 Kx=RSA      Au=RSA  Enc=None      Mac=MD5
+EDH-RSA-DES-CBC3-SHA    SSLv3 Kx=DH       Au=RSA  Enc=3DES(168) Mac=SHA1
+...                     ...               ...     ...           ...
+EXP-RC4-MD5             SSLv3 Kx=RSA(512) Au=RSA  Enc=RC4(40)   Mac=MD5  export
+EXP-RC2-CBC-MD5         SSLv2 Kx=RSA(512) Au=RSA  Enc=RC2(40)   Mac=MD5  export
+EXP-RC4-MD5             SSLv2 Kx=RSA(512) Au=RSA  Enc=RC4(40)   Mac=MD5  export
+

The complete list of particular RSA & DH ciphers for SSL is given in Table 2.

Example

+SSLCipherSuite RSA:!EXP:!NULL:+HIGH:+MEDIUM:-LOW +

+ + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + +

Cipher-Tag	Protocol	Key Ex.	Auth.	Enc.	MAC	Type
RSA Ciphers:
`DES-CBC3-SHA`	SSLv3	RSA	RSA	3DES(168)	SHA1
`DES-CBC3-MD5`	SSLv2	RSA	RSA	3DES(168)	MD5
`IDEA-CBC-SHA`	SSLv3	RSA	RSA	IDEA(128)	SHA1
`RC4-SHA`	SSLv3	RSA	RSA	RC4(128)	SHA1
`RC4-MD5`	SSLv3	RSA	RSA	RC4(128)	MD5
`IDEA-CBC-MD5`	SSLv2	RSA	RSA	IDEA(128)	MD5
`RC2-CBC-MD5`	SSLv2	RSA	RSA	RC2(128)	MD5
`RC4-MD5`	SSLv2	RSA	RSA	RC4(128)	MD5
`DES-CBC-SHA`	SSLv3	RSA	RSA	DES(56)	SHA1
`RC4-64-MD5`	SSLv2	RSA	RSA	RC4(64)	MD5
`DES-CBC-MD5`	SSLv2	RSA	RSA	DES(56)	MD5
`EXP-DES-CBC-SHA`	SSLv3	RSA(512)	RSA	DES(40)	SHA1	export
`EXP-RC2-CBC-MD5`	SSLv3	RSA(512)	RSA	RC2(40)	MD5	export
`EXP-RC4-MD5`	SSLv3	RSA(512)	RSA	RC4(40)	MD5	export
`EXP-RC2-CBC-MD5`	SSLv2	RSA(512)	RSA	RC2(40)	MD5	export
`EXP-RC4-MD5`	SSLv2	RSA(512)	RSA	RC4(40)	MD5	export
`NULL-SHA`	SSLv3	RSA	RSA	None	SHA1
`NULL-MD5`	SSLv3	RSA	RSA	None	MD5
Diffie-Hellman Ciphers:
`ADH-DES-CBC3-SHA`	SSLv3	DH	None	3DES(168)	SHA1
`ADH-DES-CBC-SHA`	SSLv3	DH	None	DES(56)	SHA1
`ADH-RC4-MD5`	SSLv3	DH	None	RC4(128)	MD5
`EDH-RSA-DES-CBC3-SHA`	SSLv3	DH	RSA	3DES(168)	SHA1
`EDH-DSS-DES-CBC3-SHA`	SSLv3	DH	DSS	3DES(168)	SHA1
`EDH-RSA-DES-CBC-SHA`	SSLv3	DH	RSA	DES(56)	SHA1
`EDH-DSS-DES-CBC-SHA`	SSLv3	DH	DSS	DES(56)	SHA1
`EXP-EDH-RSA-DES-CBC-SHA`	SSLv3	DH(512)	RSA	DES(40)	SHA1	export
`EXP-EDH-DSS-DES-CBC-SHA`	SSLv3	DH(512)	DSS	DES(40)	SHA1	export
`EXP-ADH-DES-CBC-SHA`	SSLv3	DH(512)	None	DES(40)	SHA1	export
`EXP-ADH-RC4-MD5`	SSLv3	DH(512)	None	RC4(40)	MD5	export

+ +

SSLEngine Directive

+ + + + + + + +

Description:	SSL Engine Operation Switch
Syntax:	`SSLEngine on\|off`
Default:	`SSLEngine off`
Context:	server config, virtual host
Status:	Extension
Module:	mod_ssl

+This directive toggles the usage of the SSL/TLS Protocol Engine. This +is usually used inside a <VirtualHost> section to enable SSL/TLS for a +particular virtual host. By default the SSL/TLS Protocol Engine is +disabled for both the main server and all configured virtual hosts.

Example

+<VirtualHost _default_:443> +SSLEngine on +... +</VirtualHost> +

+ +

SSLInsecureRenegotiation Directive

+ + + + + + + + +

Description:	Option to enable support for insecure renegotiation
Syntax:	`SSLInsecureRenegotiation flag`
Default:	`SSLInsecureRenegotiation off`
Context:	server config, virtual host
Status:	Extension
Module:	mod_ssl
Compatibility:	Available in httpd 2.0.64 and later, if using OpenSSL 0.9.8m or later

As originally specified, all versions of the SSL and TLS protocols +(up to and including TLS/1.2) were vulnerable to a Man-in-the-Middle +attack +(CVE-2009-3555) +during a renegotiation. This vulnerability allowed an attacker to +"prefix" a chosen plaintext to the HTTP request as seen by the web +server. A protocol extension was developed which fixed this +vulnerability if supported by both client and server.

+ +

If mod_ssl is linked against OpenSSL version 0.9.8m +or later, by default renegotiation is only supported with +clients supporting the new protocol extension. If this directive is +enabled, renegotiation will be allowed with old (unpatched) clients, +albeit insecurely.

+ +

Security warning

If this directive is enabled, SSL connections will be vulnerable to +the Man-in-the-Middle prefix attack as described +in CVE-2009-3555.

+ +

Example

+SSLInsecureRenegotiation on +

+ +

The SSL_SECURE_RENEG environment variable can be used +from an SSI or CGI script to determine whether secure renegotiation is +supported for a given SSL connection.

+ + +

SSLMutex Directive

+ + + + + + + +

Description:	Semaphore for internal mutual exclusion of +operations
Syntax:	`SSLMutex type`
Default:	`SSLMutex none`
Context:	server config
Status:	Extension
Module:	mod_ssl

+This configures the SSL engine's semaphore (aka. lock) which is used for mutual +exclusion of operations which have to be done in a synchronized way between the +pre-forked Apache server processes. This directive can only be used in the +global server context because it's only useful to have one global mutex. +This directive is designed to closely match the +AcceptMutex directive

+The following Mutex types are available:

none | no +
+ This is the default where no Mutex is used at all. Use it at your own + risk. But because currently the Mutex is mainly used for synchronizing + write access to the SSL Session Cache you can live without it as long + as you accept a sometimes garbled Session Cache. So it's not recommended + to leave this the default. Instead configure a real Mutex.
posixsem +
+ This is an elegant Mutex variant where a Posix Semaphore is used when possible. + It is only available when the underlying platform + and APR supports it.
sysvsem +
+ This is a somewhat elegant Mutex variant where a SystemV IPC Semaphore is used when + possible. It is possible to "leak" SysV semaphores if processes crash before + the semaphore is removed. It is only available when the underlying platform + and APR supports it.
sem +
+ This directive tells the SSL Module to pick the "best" semaphore implementation + available to it, choosing between Posix and SystemV IPC, in that order. It is only + available when the underlying platform and APR supports at least one of the 2.
pthread +
+ This directive tells the SSL Module to use Posix thread mutexes. It is only available + if the underlying platform and APR supports it.
fcntl:/path/to/mutex +
+ This is a portable Mutex variant where a physical (lock-)file and the fcntl() + fucntion are used as the Mutex. + Always use a local disk filesystem for /path/to/mutex and never a file + residing on a NFS- or AFS-filesystem. It is only available when the underlying platform + and APR supports it. Note: Internally, the Process ID (PID) of the + Apache parent process is automatically appended to + /path/to/mutex to make it unique, so you don't have to worry + about conflicts yourself. Notice that this type of mutex is not available + under the Win32 environment. There you have to use the semaphore + mutex.
flock:/path/to/mutex +
+ This is similar to the fcntl:/path/to/mutex method with the + exception that the flock() function is used to provide file + locking. It is only available when the underlying platform + and APR supports it.
file:/path/to/mutex +
+ This directive tells the SSL Module to pick the "best" file locking implementation + available to it, choosing between fcntl and flock, + in that order. It is only available when the underlying platform and APR supports + at least one of the 2.
default | yes +
+ This directive tells the SSL Module to pick the default locking implementation + as determined by the platform and APR.

Example

+SSLMutex file:/usr/local/apache/logs/ssl_mutex +

+ +

SSLOptions Directive

+ + + + + + + +

Description:	Configure various SSL engine run-time options
Syntax:	`SSLOptions [+\|-]option ...`
Context:	server config, virtual host, directory, .htaccess
Override:	Options
Status:	Extension
Module:	mod_ssl

+This directive can be used to control various run-time options on a +per-directory basis. Normally, if multiple SSLOptions +could apply to a directory, then the most specific one is taken +completely; the options are not merged. However if all the +options on the SSLOptions directive are preceded by a +plus (+) or minus (-) symbol, the options +are merged. Any options preceded by a + are added to the +options currently in force, and any options preceded by a +- are removed from the options currently in force.

+The available options are:

StdEnvVars +
+ When this option is enabled, the standard set of SSL related CGI/SSI + environment variables are created. This per default is disabled for + performance reasons, because the information extraction step is a + rather expensive operation. So one usually enables this option for + CGI and SSI requests only.
+
CompatEnvVars +
+ When this option is enabled, additional CGI/SSI environment variables are + created for backward compatibility to other Apache SSL solutions. Look in + the Compatibility chapter for details + on the particular variables generated.
+
ExportCertData +
+ When this option is enabled, additional CGI/SSI environment variables are + created: SSL_SERVER_CERT, SSL_CLIENT_CERT and + SSL_CLIENT_CERT_CHAINn (with n = 0,1,2,..). + These contain the PEM-encoded X.509 Certificates of server and client for + the current HTTPS connection and can be used by CGI scripts for deeper + Certificate checking. Additionally all other certificates of the client + certificate chain are provided, too. This bloats up the environment a + little bit which is why you have to use this option to enable it on + demand.
+
FakeBasicAuth +
+ When this option is enabled, the Subject Distinguished Name (DN) of the + Client X509 Certificate is translated into a HTTP Basic Authorization + username. This means that the standard Apache authentication methods can + be used for access control. The user name is just the Subject of the + Client's X509 Certificate (can be determined by running OpenSSL's + openssl x509 command: openssl x509 -noout -subject -in +certificate.crt). Note that no password is + obtained from the user. Every entry in the user file needs this password: + ``xxj31ZMTZzkVA'', which is the DES-encrypted version of the + word `password''. Those who live under MD5-based encryption + (for instance under FreeBSD or BSD/OS, etc.) should use the following MD5 + hash of the same word: ``$1$OXLyS...$Owx8s2/m9/gfkcRVXzgoE/''.
+
StrictRequire +
+ This forces forbidden access when SSLRequireSSL or + SSLRequire successfully decided that access should be + forbidden. Usually the default is that in the case where a ``Satisfy + any'' directive is used, and other access restrictions are passed, + denial of access due to SSLRequireSSL or + SSLRequire is overridden (because that's how the Apache + Satisfy mechanism should work.) But for strict access restriction + you can use SSLRequireSSL and/or SSLRequire in + combination with an ``SSLOptions +StrictRequire''. Then an + additional ``Satisfy Any'' has no chance once mod_ssl has + decided to deny access.
+
OptRenegotiate +
+ This enables optimized SSL connection renegotiation handling when SSL + directives are used in per-directory context. By default a strict + scheme is enabled where every per-directory reconfiguration of + SSL parameters causes a full SSL renegotiation handshake. When this + option is used mod_ssl tries to avoid unnecessary handshakes by doing more + granular (but still safe) parameter checks. Nevertheless these granular + checks sometimes maybe not what the user expects, so enable this on a + per-directory basis only, please.
+

Example

+SSLOptions +FakeBasicAuth -StrictRequire +<Files ~ "\.(cgi|shtml)$"> + SSLOptions +StdEnvVars +CompatEnvVars -ExportCertData +<Files> +

+ +

SSLPassPhraseDialog Directive

+ + + + + + + +

Description:	Type of pass phrase dialog for encrypted private +keys
Syntax:	`SSLPassPhraseDialog type`
Default:	`SSLPassPhraseDialog builtin`
Context:	server config
Status:	Extension
Module:	mod_ssl

+When Apache starts up it has to read the various Certificate (see +SSLCertificateFile) and +Private Key (see SSLCertificateKeyFile) files of the +SSL-enabled virtual servers. Because for security reasons the Private +Key files are usually encrypted, mod_ssl needs to query the +administrator for a Pass Phrase in order to decrypt those files. This +query can be done in two ways which can be configured by +type:

builtin +
+ This is the default where an interactive terminal dialog occurs at startup + time just before Apache detaches from the terminal. Here the administrator + has to manually enter the Pass Phrase for each encrypted Private Key file. + Because a lot of SSL-enabled virtual hosts can be configured, the + following reuse-scheme is used to minimize the dialog: When a Private Key + file is encrypted, all known Pass Phrases (at the beginning there are + none, of course) are tried. If one of those known Pass Phrases succeeds no + dialog pops up for this particular Private Key file. If none succeeded, + another Pass Phrase is queried on the terminal and remembered for the next + round (where it perhaps can be reused).
+
+ This scheme allows mod_ssl to be maximally flexible (because for N encrypted + Private Key files you can use N different Pass Phrases - but then + you have to enter all of them, of course) while minimizing the terminal + dialog (i.e. when you use a single Pass Phrase for all N Private Key files + this Pass Phrase is queried only once).
exec:/path/to/program +
+ Here an external program is configured which is called at startup for each + encrypted Private Key file. It is called with two arguments (the first is + of the form ``servername:portnumber'', the second is either + ``RSA'' or ``DSA''), which indicate for which + server and algorithm it has to print the corresponding Pass Phrase to + stdout. The intent is that this external program first runs + security checks to make sure that the system is not compromised by an + attacker, and only when these checks were passed successfully it provides + the Pass Phrase.
+
+ Both these security checks, and the way the Pass Phrase is determined, can + be as complex as you like. Mod_ssl just defines the interface: an + executable program which provides the Pass Phrase on stdout. + Nothing more or less! So, if you're really paranoid about security, here + is your interface. Anything else has to be left as an exercise to the + administrator, because local security requirements are so different.
+
+ The reuse-algorithm above is used here, too. In other words: The external + program is called only once per unique Pass Phrase.

+Example:

+SSLPassPhraseDialog exec:/usr/local/apache/sbin/pp-filter +

+ +

SSLProtocol Directive

+ + + + + + + + +

Description:	Configure usable SSL protocol flavors
Syntax:	`SSLProtocol [+\|-]protocol ...`
Default:	`SSLProtocol all`
Context:	server config, virtual host
Override:	Options
Status:	Extension
Module:	mod_ssl

+This directive can be used to control the SSL protocol flavors mod_ssl should +use when establishing its server environment. Clients then can only connect +with one of the provided protocols.

+The available (case-insensitive) protocols are:

SSLv2 +
+ This is the Secure Sockets Layer (SSL) protocol, version 2.0. It is the + original SSL protocol as designed by Netscape Corporation.
SSLv3 +
+ This is the Secure Sockets Layer (SSL) protocol, version 3.0. It is the + successor to SSLv2 and the currently (as of February 1999) de-facto + standardized SSL protocol from Netscape Corporation. It's supported by + almost all popular browsers.
TLSv1 +
+ This is the Transport Layer Security (TLS) protocol, version 1.0. It is the + successor to SSLv3 and currently (as of February 1999) still under + construction by the Internet Engineering Task Force (IETF). It's still + not supported by any popular browsers.
All +
+ This is a shortcut for ``+SSLv2 +SSLv3 +TLSv1'' and a + convinient way for enabling all protocols except one when used in + combination with the minus sign on a protocol as the example above + shows.

Example

+# enable SSLv3 and TLSv1, but not SSLv2 +SSLProtocol all -SSLv2 +

+ +

SSLProxyCACertificateFile Directive

+ + + + + + +

Description:	File of concatenated PEM-encoded CA Certificates +for Remote Server Auth
Syntax:	`SSLProxyCACertificateFile file-path`
Context:	server config, virtual host
Status:	Extension
Module:	mod_ssl

+This directive sets the all-in-one file where you can assemble the +Certificates of Certification Authorities (CA) whose remote servers you deal +with. These are used for Remote Server Authentication. Such a file is simply the +concatenation of the various PEM-encoded Certificate files, in order of +preference. This can be used alternatively and/or additionally to +SSLProxyCACertificatePath.

Example

+SSLProxyCACertificateFile /usr/local/apache2/conf/ssl.crt/ca-bundle-remote-server.crt +

+ +

SSLProxyCACertificatePath Directive

+ + + + + + +

Description:	Directory of PEM-encoded CA Certificates for +Remote Server Auth
Syntax:	`SSLProxyCACertificatePath directory-path`
Context:	server config, virtual host
Status:	Extension
Module:	mod_ssl

+This directive sets the directory where you keep the Certificates of +Certification Authorities (CAs) whose remote servers you deal with. These are used to +verify the remote server certificate on Remote Server Authentication.

Example

+SSLProxyCACertificatePath /usr/local/apache2/conf/ssl.crt/ +

+ +

SSLProxyCARevocationFile Directive

+ + + + + + +

Description:	File of concatenated PEM-encoded CA CRLs for +Remote Server Auth
Syntax:	`SSLProxyCARevocationFile file-path`
Context:	server config, virtual host
Status:	Extension
Module:	mod_ssl

+This directive sets the all-in-one file where you can +assemble the Certificate Revocation Lists (CRL) of Certification +Authorities (CA) whose remote servers you deal with. These are used +for Remote Server Authentication. Such a file is simply the concatenation of +the various PEM-encoded CRL files, in order of preference. This can be +used alternatively and/or additionally to SSLProxyCARevocationPath.

Example

+SSLProxyCARevocationFile /usr/local/apache2/conf/ssl.crl/ca-bundle-remote-server.crl +

+ +

SSLProxyCARevocationPath Directive

+ + + + + + +

Description:	Directory of PEM-encoded CA CRLs for +Remote Server Auth
Syntax:	`SSLProxyCARevocationPath directory-path`
Context:	server config, virtual host
Status:	Extension
Module:	mod_ssl

+This directive sets the directory where you keep the Certificate Revocation +Lists (CRL) of Certification Authorities (CAs) whose remote servers you deal with. +These are used to revoke the remote server certificate on Remote Server Authentication.

Example

+SSLProxyCARevocationPath /usr/local/apache2/conf/ssl.crl/ +

+ +

SSLProxyCipherSuite Directive

+ + + + + + + + +

Description:	Cipher Suite available for negotiation in SSL +proxy handshake
Syntax:	`SSLProxyCipherSuite cipher-spec`
Default:	`SSLProxyCipherSuite ALL:!ADH:RC4+RSA:+HIGH:+MEDIUM:+LOW:+SSLv2:+EXP`
Context:	server config, virtual host, directory, .htaccess
Override:	AuthConfig
Status:	Extension
Module:	mod_ssl

Equivalent to SSLCipherSuite, but for the proxy connection. +Please refer to SSLCipherSuite +for additional information.

+ +

SSLProxyEngine Directive

+ + + + + + + +

Description:	SSL Proxy Engine Operation Switch
Syntax:	`SSLProxyEngine on\|off`
Default:	`SSLProxyEngine off`
Context:	server config, virtual host
Status:	Extension
Module:	mod_ssl

+This directive toggles the usage of the SSL/TLS Protocol Engine for proxy. This +is usually used inside a <VirtualHost> section to enable SSL/TLS for proxy +usage in a particular virtual host. By default the SSL/TLS Protocol Engine is +disabled for proxy image both for the main server and all configured virtual hosts.

Example

+<VirtualHost _default_:443> +SSLProxyEngine on +... +</VirtualHost> +

+ +

SSLProxyMachineCertificateFile Directive

+ + + + + + + +

Description:	File of concatenated PEM-encoded client certificates and keys to be used by the proxy
Syntax:	`SSLProxyMachineCertificateFile filename`
Context:	server config
Override:	Not applicable
Status:	Extension
Module:	mod_ssl

+This directive sets the all-in-one file where you keep the certificates and +keys used for authentication of the proxy server to remote servers. +

+This referenced file is simply the concatenation of the various PEM-encoded +certificate files, in order of preference. Use this directive alternatively +or additionally to SSLProxyMachineCertificatePath. +

Currently there is no support for encrypted private keys

+Example:

+SSLProxyMachineCertificateFile /usr/local/apache2/conf/ssl.crt/proxy.pem +

+ +

SSLProxyMachineCertificatePath Directive

+ + + + + + + +

Description:	Directory of PEM-encoded client certificates and keys to be used by the proxy
Syntax:	`SSLProxyMachineCertificatePath directory`
Context:	server config
Override:	Not applicable
Status:	Extension
Module:	mod_ssl

+This directive sets the directory where you keep the certificates and +keys used for authentication of the proxy server to remote servers. +

The files in this directory must be PEM-encoded and are accessed through +hash filenames. Additionally, you must create symbolic links named +hash-value.N. And you should always make sure this +directory contains the appropriate symbolic links. Use the Makefile which +comes with mod_ssl to accomplish this task. +

Currently there is no support for encrypted private keys

+Example:

+SSLProxyMachineCertificatePath /usr/local/apache2/conf/proxy.crt/ +

+ +

SSLProxyProtocol Directive

+ + + + + + + + +

Description:	Configure usable SSL protocol flavors for proxy usage
Syntax:	`SSLProxyProtocol [+\|-]protocol ...`
Default:	`SSLProxyProtocol all`
Context:	server config, virtual host
Override:	Options
Status:	Extension
Module:	mod_ssl

+ +

+This directive can be used to control the SSL protocol flavors mod_ssl should +use when establishing its server environment for proxy . It will only connect +to servers using one of the provided protocols.

Please refer to SSLProtocol +for additional information. +

+ +

SSLProxyVerify Directive

+ + + + + + + + +

Description:	Type of remote server Certificate verification
Syntax:	`SSLProxyVerify level`
Default:	`SSLProxyVerify none`
Context:	server config, virtual host, directory, .htaccess
Override:	AuthConfig
Status:	Extension
Module:	mod_ssl

+This directive sets the Certificate verification level for the remote server +Authentication. Notice that this directive can be used both in per-server and +per-directory context. In per-server context it applies to the remote server +authentication process used in the standard SSL handshake when a connection is +established. In per-directory context it forces a SSL renegotation with the +reconfigured remote server verification level after the HTTP request was read but +before the HTTP response is sent.

+The following levels are available for level:

none: + no remote server Certificate is required at all
optional: + the remote server may present a valid Certificate
require: + the remote server has to present a valid Certificate
optional_no_ca: + the remote server may present a valid Certificate
+ but it need not to be (successfully) verifiable.

In practice only levels none and +require are really interesting, because level +optional doesn't work with all servers and level +optional_no_ca is actually against the idea of +authentication (but can be used to establish SSL test pages, etc.)

Example

+SSLProxyVerify require +

+ +

SSLProxyVerifyDepth Directive

+ + + + + + + + +

Description:	Maximum depth of CA Certificates in Remote Server +Certificate verification
Syntax:	`SSLProxyVerifyDepth number`
Default:	`SSLProxyVerifyDepth 1`
Context:	server config, virtual host, directory, .htaccess
Override:	AuthConfig
Status:	Extension
Module:	mod_ssl

+This directive sets how deeply mod_ssl should verify before deciding that the +remote server does not have a valid certificate. Notice that this directive can be +used both in per-server and per-directory context. In per-server context it +applies to the client authentication process used in the standard SSL +handshake when a connection is established. In per-directory context it forces +a SSL renegotation with the reconfigured remote server verification depth after the +HTTP request was read but before the HTTP response is sent.

+The depth actually is the maximum number of intermediate certificate issuers, +i.e. the number of CA certificates which are max allowed to be followed while +verifying the remote server certificate. A depth of 0 means that self-signed +remote server certificates are accepted only, the default depth of 1 means +the remote server certificate can be self-signed or has to be signed by a CA +which is directly known to the server (i.e. the CA's certificate is under +SSLProxyCACertificatePath), etc.

Example

+SSLProxyVerifyDepth 10 +

+ +

SSLRandomSeed Directive

+ + + + + + +

Description:	Pseudo Random Number Generator (PRNG) seeding +source
Syntax:	`SSLRandomSeed context source +[bytes]`
Context:	server config
Status:	Extension
Module:	mod_ssl

+This configures one or more sources for seeding the Pseudo Random Number +Generator (PRNG) in OpenSSL at startup time (context is +startup) and/or just before a new SSL connection is established +(context is connect). This directive can only be used +in the global server context because the PRNG is a global facility.

+The following source variants are available:

builtin +
This is the always available builtin seeding source. It's usage + consumes minimum CPU cycles under runtime and hence can be always used + without drawbacks. The source used for seeding the PRNG contains of the + current time, the current process id and (when applicable) a randomly + choosen 1KB extract of the inter-process scoreboard structure of Apache. + The drawback is that this is not really a strong source and at startup + time (where the scoreboard is still not available) this source just + produces a few bytes of entropy. So you should always, at least for the + startup, use an additional seeding source.
file:/path/to/source +
+ This variant uses an external file /path/to/source as the + source for seeding the PRNG. When bytes is specified, only the + first bytes number of bytes of the file form the entropy (and + bytes is given to /path/to/source as the first + argument). When bytes is not specified the whole file forms the + entropy (and 0 is given to /path/to/source as + the first argument). Use this especially at startup time, for instance + with an available /dev/random and/or + /dev/urandom devices (which usually exist on modern Unix + derivates like FreeBSD and Linux).
+
+ But be careful: Usually /dev/random provides only as + much entropy data as it actually has, i.e. when you request 512 bytes of + entropy, but the device currently has only 100 bytes available two things + can happen: On some platforms you receive only the 100 bytes while on + other platforms the read blocks until enough bytes are available (which + can take a long time). Here using an existing /dev/urandom is + better, because it never blocks and actually gives the amount of requested + data. The drawback is just that the quality of the received data may not + be the best.
+
+ On some platforms like FreeBSD one can even control how the entropy is + actually generated, i.e. by which system interrupts. More details one can + find under rndcontrol(8) on those platforms. Alternatively, when + your system lacks such a random device, you can use tool + like EGD + (Entropy Gathering Daemon) and run it's client program with the + exec:/path/to/program/ variant (see below) or use + egd:/path/to/egd-socket (see below).
exec:/path/to/program +
+ This variant uses an external executable + /path/to/program as the source for seeding the + PRNG. When bytes is specified, only the first + bytes number of bytes of its stdout contents + form the entropy. When bytes is not specified, the + entirety of the data produced on stdout form the + entropy. Use this only at startup time when you need a very strong + seeding with the help of an external program (for instance as in + the example above with the truerand utility you can + find in the mod_ssl distribution which is based on the AT&T + truerand library). Using this in the connection context + slows down the server too dramatically, of course. So usually you + should avoid using external programs in that context.
egd:/path/to/egd-socket (Unix only) +
+ This variant uses the Unix domain socket of the + external Entropy Gathering Daemon (EGD) (see http://www.lothar.com/tech + /crypto/) to seed the PRNG. Use this if no random device exists + on your platform.

Example

+SSLRandomSeed startup builtin +SSLRandomSeed startup file:/dev/random +SSLRandomSeed startup file:/dev/urandom 1024 +SSLRandomSeed startup exec:/usr/local/bin/truerand 16 +SSLRandomSeed connect builtin +SSLRandomSeed connect file:/dev/random +SSLRandomSeed connect file:/dev/urandom 1024 +

+ +

SSLRequire Directive

+ + + + + + + +

Description:	Allow access only when an arbitrarily complex +boolean expression is true
Syntax:	`SSLRequire expression`
Context:	directory, .htaccess
Override:	AuthConfig
Status:	Extension
Module:	mod_ssl

+This directive specifies a general access requirement which has to be +fulfilled in order to allow access. It's a very powerful directive because the +requirement specification is an arbitrarily complex boolean expression +containing any number of access checks.

+The expression must match the following syntax (given as a BNF +grammar notation):

+expr     ::= "true" | "false"
+           | "!" expr
+           | expr "&&" expr
+           | expr "||" expr
+           | "(" expr ")"
+           | comp
+
+comp     ::= word "==" word | word "eq" word
+           | word "!=" word | word "ne" word
+           | word "<"  word | word "lt" word
+           | word "<=" word | word "le" word
+           | word ">"  word | word "gt" word
+           | word ">=" word | word "ge" word
+           | word "in" "{" wordlist "}"
+           | word "=~" regex
+           | word "!~" regex
+
+wordlist ::= word
+           | wordlist "," word
+
+word     ::= digit
+           | cstring
+           | variable
+           | function
+
+digit    ::= [0-9]+
+cstring  ::= "..."
+variable ::= "%{" varname "}"
+function ::= funcname "(" funcargs ")"
+

while for varname any variable from Table 3 can be used. Finally for +funcname the following functions are available:

file(filename) +
+ This function takes one string argument and expands to the contents of the + file. This is especially useful for matching this contents against a + regular expression, etc.
+

Notice that expression is first parsed into an internal machine +representation and then evaluated in a second step. Actually, in Global and +Per-Server Class context expression is parsed at startup time and +at runtime only the machine representation is executed. For Per-Directory +context this is different: here expression has to be parsed and +immediately executed for every request.

Example

+SSLRequire ( %{SSL_CIPHER} !~ m/^(EXP|NULL)-/ \ + and %{SSL_CLIENT_S_DN_O} eq "Snake Oil, Ltd." \ + and %{SSL_CLIENT_S_DN_OU} in {"Staff", "CA", "Dev"} \ + and %{TIME_WDAY} >= 1 and %{TIME_WDAY} <= 5 \ + and %{TIME_HOUR} >= 8 and %{TIME_HOUR} <= 20 ) \ + or %{REMOTE_ADDR} =~ m/^192\.76\.162\.[0-9]+$/ +

+ +

Standard CGI/1.0 and Apache variables:

+HTTP_USER_AGENT        PATH_INFO             AUTH_TYPE
+HTTP_REFERER           QUERY_STRING          SERVER_SOFTWARE
+HTTP_COOKIE            REMOTE_HOST           API_VERSION
+HTTP_FORWARDED         REMOTE_IDENT          TIME_YEAR
+HTTP_HOST              IS_SUBREQ             TIME_MON
+HTTP_PROXY_CONNECTION  DOCUMENT_ROOT         TIME_DAY
+HTTP_ACCEPT            SERVER_ADMIN          TIME_HOUR
+HTTP:headername        SERVER_NAME           TIME_MIN
+THE_REQUEST            SERVER_PORT           TIME_SEC
+REQUEST_METHOD         SERVER_PROTOCOL       TIME_WDAY
+REQUEST_SCHEME         REMOTE_ADDR           TIME
+REQUEST_URI            REMOTE_USER           ENV:variablename
+REQUEST_FILENAME
+

SSL-related variables:

+HTTPS                  SSL_CLIENT_M_VERSION   SSL_SERVER_M_VERSION
+                       SSL_CLIENT_M_SERIAL    SSL_SERVER_M_SERIAL
+SSL_PROTOCOL           SSL_CLIENT_V_START     SSL_SERVER_V_START
+SSL_SESSION_ID         SSL_CLIENT_V_END       SSL_SERVER_V_END
+SSL_CIPHER             SSL_CLIENT_S_DN        SSL_SERVER_S_DN
+SSL_CIPHER_EXPORT      SSL_CLIENT_S_DN_C      SSL_SERVER_S_DN_C
+SSL_CIPHER_ALGKEYSIZE  SSL_CLIENT_S_DN_ST     SSL_SERVER_S_DN_ST
+SSL_CIPHER_USEKEYSIZE  SSL_CLIENT_S_DN_L      SSL_SERVER_S_DN_L
+SSL_VERSION_LIBRARY    SSL_CLIENT_S_DN_O      SSL_SERVER_S_DN_O
+SSL_VERSION_INTERFACE  SSL_CLIENT_S_DN_OU     SSL_SERVER_S_DN_OU
+                       SSL_CLIENT_S_DN_CN     SSL_SERVER_S_DN_CN
+                       SSL_CLIENT_S_DN_T      SSL_SERVER_S_DN_T
+                       SSL_CLIENT_S_DN_I      SSL_SERVER_S_DN_I
+                       SSL_CLIENT_S_DN_G      SSL_SERVER_S_DN_G
+                       SSL_CLIENT_S_DN_S      SSL_SERVER_S_DN_S
+                       SSL_CLIENT_S_DN_D      SSL_SERVER_S_DN_D
+                       SSL_CLIENT_S_DN_UID    SSL_SERVER_S_DN_UID
+                       SSL_CLIENT_S_DN_Email  SSL_SERVER_S_DN_Email
+                       SSL_CLIENT_I_DN        SSL_SERVER_I_DN
+                       SSL_CLIENT_I_DN_C      SSL_SERVER_I_DN_C
+                       SSL_CLIENT_I_DN_ST     SSL_SERVER_I_DN_ST
+                       SSL_CLIENT_I_DN_L      SSL_SERVER_I_DN_L
+                       SSL_CLIENT_I_DN_O      SSL_SERVER_I_DN_O
+                       SSL_CLIENT_I_DN_OU     SSL_SERVER_I_DN_OU
+                       SSL_CLIENT_I_DN_CN     SSL_SERVER_I_DN_CN
+                       SSL_CLIENT_I_DN_T      SSL_SERVER_I_DN_T
+                       SSL_CLIENT_I_DN_I      SSL_SERVER_I_DN_I
+                       SSL_CLIENT_I_DN_G      SSL_SERVER_I_DN_G
+                       SSL_CLIENT_I_DN_S      SSL_SERVER_I_DN_S
+                       SSL_CLIENT_I_DN_D      SSL_SERVER_I_DN_D
+                       SSL_CLIENT_I_DN_UID    SSL_SERVER_I_DN_UID
+                       SSL_CLIENT_I_DN_Email  SSL_SERVER_I_DN_Email
+                       SSL_CLIENT_A_SIG       SSL_SERVER_A_SIG
+                       SSL_CLIENT_A_KEY       SSL_SERVER_A_KEY
+                       SSL_CLIENT_CERT        SSL_SERVER_CERT
+                       SSL_CLIENT_CERT_CHAINn
+                       SSL_CLIENT_VERIFY
+

+ +

SSLRequireSSL Directive

+ + + + + + + +

Description:	Deny access when SSL is not used for the +HTTP request
Syntax:	`SSLRequireSSL`
Context:	directory, .htaccess
Override:	AuthConfig
Status:	Extension
Module:	mod_ssl

+This directive forbids access unless HTTP over SSL (i.e. HTTPS) is enabled for +the current connection. This is very handy inside the SSL-enabled virtual +host or directories for defending against configuration errors that expose +stuff that should be protected. When this directive is present all requests +are denied which are not using SSL.

Example

+SSLRequireSSL +

+ +

SSLSessionCache Directive

+ + + + + + + +

Description:	Type of the global/inter-process SSL Session +Cache
Syntax:	`SSLSessionCache type`
Default:	`SSLSessionCache none`
Context:	server config
Status:	Extension
Module:	mod_ssl

+This configures the storage type of the global/inter-process SSL Session +Cache. This cache is an optional facility which speeds up parallel request +processing. For requests to the same server process (via HTTP keep-alive), +OpenSSL already caches the SSL session information locally. But because modern +clients request inlined images and other data via parallel requests (usually +up to four parallel requests are common) those requests are served by +different pre-forked server processes. Here an inter-process cache +helps to avoid unneccessary session handshakes.

+The following two storage types are currently supported:

none +
+ This is the default and just disables the global/inter-process Session + Cache. There is no drawback in functionality, but a noticeable speed + penalty can be observed.
dbm:/path/to/datafile +
+ This makes use of a DBM hashfile on the local disk to synchronize the + local OpenSSL memory caches of the server processes. The slight increase + in I/O on the server results in a visible request speedup for your + clients, so this type of storage is generally recommended.
shm:/path/to/datafile[(size)] +
+ This makes use of a high-performance hash table (approx. size bytes + in size) inside a shared memory segment in RAM (established via + /path/to/datafile) to synchronize the local OpenSSL memory + caches of the server processes. This storage type is not available on all + platforms.

Examples

+SSLSessionCache dbm:/usr/local/apache/logs/ssl_gcache_data +SSLSessionCache shm:/usr/local/apache/logs/ssl_gcache_data(512000) +

+ +

SSLSessionCacheTimeout Directive

+ + + + + + + +

Description:	Number of seconds before an SSL session expires +in the Session Cache
Syntax:	`SSLSessionCacheTimeout seconds`
Default:	`SSLSessionCacheTimeout 300`
Context:	server config, virtual host
Status:	Extension
Module:	mod_ssl

+This directive sets the timeout in seconds for the information stored in the +global/inter-process SSL Session Cache and the OpenSSL internal memory cache. +It can be set as low as 15 for testing, but should be set to higher +values like 300 in real life.

Example

+SSLSessionCacheTimeout 600 +

+ +

SSLUserName Directive

+ + + + + + + + +

Description:	Variable name to determine user name
Syntax:	`SSLUserName varname`
Context:	server config, directory, .htaccess
Override:	AuthConfig
Status:	Extension
Module:	mod_ssl
Compatibility:	Available in Apache 2.0.51 and later

+This directive sets the "user" field in the Apache request object. +This is used by lower modules to identify the user with a character +string. In particular, this may cause the environment variable +REMOTE_USER to be set. The varname can be +any of the SSL environment variables.

Example

+SSLUserName SSL_CLIENT_S_DN_CN +

+ +

SSLVerifyClient Directive

+ + + + + + + + +

Description:	Type of Client Certificate verification
Syntax:	`SSLVerifyClient level`
Default:	`SSLVerifyClient none`
Context:	server config, virtual host, directory, .htaccess
Override:	AuthConfig
Status:	Extension
Module:	mod_ssl

+This directive sets the Certificate verification level for the Client +Authentication. Notice that this directive can be used both in per-server and +per-directory context. In per-server context it applies to the client +authentication process used in the standard SSL handshake when a connection is +established. In per-directory context it forces a SSL renegotation with the +reconfigured client verification level after the HTTP request was read but +before the HTTP response is sent.

+The following levels are available for level:

none: + no client Certificate is required at all
optional: + the client may present a valid Certificate
require: + the client has to present a valid Certificate
optional_no_ca: + the client may present a valid Certificate
+ but it need not to be (successfully) verifiable.

In practice only levels none and +require are really interesting, because level +optional doesn't work with all browsers and level +optional_no_ca is actually against the idea of +authentication (but can be used to establish SSL test pages, etc.)

Example

+SSLVerifyClient require +

+ +

SSLVerifyDepth Directive

+ + + + + + + + +

Description:	Maximum depth of CA Certificates in Client +Certificate verification
Syntax:	`SSLVerifyDepth number`
Default:	`SSLVerifyDepth 1`
Context:	server config, virtual host, directory, .htaccess
Override:	AuthConfig
Status:	Extension
Module:	mod_ssl

+This directive sets how deeply mod_ssl should verify before deciding that the +clients don't have a valid certificate. Notice that this directive can be +used both in per-server and per-directory context. In per-server context it +applies to the client authentication process used in the standard SSL +handshake when a connection is established. In per-directory context it forces +a SSL renegotation with the reconfigured client verification depth after the +HTTP request was read but before the HTTP response is sent.

+The depth actually is the maximum number of intermediate certificate issuers, +i.e. the number of CA certificates which are max allowed to be followed while +verifying the client certificate. A depth of 0 means that self-signed client +certificates are accepted only, the default depth of 1 means the client +certificate can be self-signed or has to be signed by a CA which is directly +known to the server (i.e. the CA's certificate is under +SSLCACertificatePath), etc.

Example

+SSLVerifyDepth 10 +

+ +

Apache Module mod_ssl

Summary

Directives

Topics

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Security warning

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