| Oracle® Database Advanced Security Administrator's Guide 10g Release 1 (10.1) Part Number B10772-01 |
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View PDF |
| Oracle® Database Advanced Security Administrator's Guide 10g Release 1 (10.1) Part Number B10772-01 |
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View PDF |
This chapter describes how to configure and use the Secure Sockets Layer (SSL) and Transport Layer Security (TLS) protocols which are supported by Oracle Advanced Security. It contains the following topics:
Secure Sockets Layer (SSL) is an industry standard protocol originally designed by Netscape Communications Corporation for securing network connections. SSL uses RSA public key cryptography in conjunction with symmetric key cryptography to provide authentication, encryption, and data integrity.
This section discusses the following topics:
Although SSL was primarily developed by Netscape Communications Corporation, the Internet Engineering Task Force (IETF) took over development of it, with Netscape's blessing, and renamed it Transport Layer Security (TLS). Essentially, TLS is an incremental improvement to SSL version 3.0.
| See Also:
The TLS Protocol Version 1.0 [RFC 2246] at the IETF Web site, which can be found at the following URL: |
Oracle Advanced Security supports authentication by using digital certificates over SSL in addition to the native encryption and data integrity capabilities of these protocols.
By using Oracle Advanced Security SSL functionality to secure communications between clients and servers, you can
You can use SSL features by themselves or in combination with other authentication methods supported by Oracle Advanced Security. For example, you can use the encryption provided by SSL in combination with the authentication provided by Kerberos. SSL supports any of the following authentication modes:
See Also:
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When a network connection over SSL is initiated, the client and server perform an SSL handshake that includes the following steps:
The authentication process consists of the following steps:
A public key infrastructure (PKI) is a substrate of network components that provide a security underpinning, based on trust assertions, for an entire organization. A PKI exists so that disparate network entities can access its security services, which use public-key cryptography, on an as-needed basis. Oracle provides a complete PKI that is based on RSA Security, Inc., Public-Key Cryptography Standards, and which interoperates with Oracle servers and clients.
Traditional private-key or symmetric-key cryptography requires a single, secret key that is shared by two or more parties to a secure communication. This key is used to both encrypt and decrypt secure messages sent between the parties, requiring prior, secure distribution of the key to each party. The problem with this method is that it is difficult to securely transmit and store the key.
Public-key cryptography provides a solution to this problem, by employing public and private key pairs and a secure method for key distribution. The freely available public key is used to encrypt messages that can only be decrypted by the holder of the associated private key. The private key is securely stored, together with other security credentials, in an encrypted container called a wallet.
Public-key algorithms can guarantee the secrecy of a message, but they don't necessarily guarantee secure communications because they don't verify the identities of the communicating parties. In order to establish secure communications, it is important to verify that the public key used to encrypt a message does in fact belong to the target recipient. Otherwise, a third party can potentially eavesdrop on the communication and intercept public key requests, substituting its own public key for a legitimate key (the man-in-the-middle attack).
In order to avoid such an attack, it is necessary to verify the owner of the public key, a process called authentication. Authentication can be accomplished through a certificate authority (CA), which is a third party that is trusted by both of the communicating parties.
The CA issues public key certificates that contain an entity's name, public key, and certain other security credentials. Such credentials typically include the CA name, the CA signature, and the certificate effective dates (From Date, To Date).
The CA uses its private key to encrypt a message, while the public key is used to decrypt it, thus verifying that the message was encrypted by the CA. The CA public key is well known, and does not have to be authenticated each time it is accessed. Such CA public keys are stored in wallets.
Public key infrastructure (PKI) components in an Oracle environment include the following:
A certificate authority (CA) is a trusted third party that certifies the identity of entities, such as users, databases, administrators, clients, and servers. When an entity requests certification, the CA verifies its identity and grants a certificate, which is signed with the CA's private key.
Different CAs may have different identification requirements when issuing certificates. Some CAs may verify a requester's identity with a driver's license, some may verify identity with the requester's fingerprints, while others may require that requesters have their certificate request form notarized.
The CA publishes its own certificate, which includes its public key. Each network entity has a list of trusted CA certificates. Before communicating, network entities exchange certificates and check that each other's certificate is signed by one of the CAs on their respective trusted CA certificate lists.
Network entities can obtain their certificates from the same or different CAs. By default, Oracle Advanced Security automatically installs trusted certificates from VeriSign, RSA, Entrust, and GTE CyberTrust when you create a new wallet.
Oracle Application Server Certificate Authority, part of Oracle Identity Management Infrastructure, is a new Oracle PKI component available in Oracle Application Server 10g (9.0.4).
A certificate is created when an entity's public key is signed by a trusted certificate authority (CA). A certificate ensures that an entity's identification information is correct and that the public key actually belongs to that entity.
A certificate contains the entity's name, public key, and an expiration date--as well as a serial number and certificate chain information. It can also contain information about the privileges associated with the certificate.
When a network entity receives a certificate, it verifies that it is a trusted certificate, that is, one that has been issued and signed by a trusted certificate authority. A certificate remains valid until it expires or until it is revoked.
Typically, when a CA signs a certificate binding a public key pair to a user identity, the certificate is valid for a specified period of time. However, certain events, such as user name changes or compromised private keys, can render a certificate invalid before the validity period expires. When this happens, the CA revokes the certificate and adds its serial number to a Certificate Revocation List (CRL). CAs periodically publish CRLs to alert the user population when it is no longer acceptable to use a particular public key to verify its associated user identity.
When servers or clients receive user certificates in an Oracle environment, they can validate the certificate by checking its expiration date, signature, and revocation status. Certificate revocation status is checked by validating it against published CRLs. If certificate revocation status checking is turned on, then the server searches for the appropriate CRL depending on how this feature has been configured. The server searches for CRLs in the following locations:
| See Also:
"Certificate Validation with Certificate Revocation Lists" for information about configuring and managing this PKI component |
A wallet is a container that is used to store authentication and signing credentials, including private keys, certificates, and trusted certificates needed by SSL. In an Oracle environment, every entity that communicates over SSL must have a wallet containing an X.509 version 3 certificate, private key, and list of trusted certificates (with the exception of Diffie-Hellman).
Security administrators use Oracle Wallet Manager to manage security credentials on the server. Wallet owners use it to manage security credentials on clients. Specifically, you use Oracle Wallet Manager to do the following:
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Note: Installation of Oracle Advanced Security 10g Release 1 (10.1) also installs Oracle Wallet Manager release 10.1. |
Oracle Advanced Security uses these devices for the following functions:
Cryptographic information can be stored on two types of hardware devices:
An Oracle environment supports hardware devices using APIs that conform to the RSA Security, Inc., Public-Key Cryptography Standards (PKCS) #11 specification.
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Note: Currently only nCipher devices are certified with Oracle Advanced Security. Certificate with other vendors is in progress. |
| See Also:
"Configuring Your System to Use Hardware Security Modules" for details configuration details. |
You can configure Oracle Advanced Security to use SSL concurrently with database usernames and passwords, RADIUS, and Kerberos, which are discussed in the following sections:
| See Also:
Appendix A, "Data Encryption and Integrity Parameters" for information about how to configure SSL with other supported authentication methods, including an example of a |
Figure 1-5, which displays the Oracle Advanced Security implementation architecture, shows that Oracle Advanced Security operates at the session layer on top of SSL and uses TCP/IP at the transport layer. This separation of functionality lets you employ SSL concurrently with other supported protocols.
| See Also:
Oracle Net Services Administrator's Guide, for information about stack communications in an Oracle networking environment |
Figure 7-1 illustrates a configuration in which SSL is used in combination with another authentication method supported by Oracle Advanced Security. In this example, SSL is used to establish the initial handshake (server authentication), and an alternative authentication method is used to authenticate the client.
Text description of the illustration asoag018.gif
Oracle Advanced Security supports two types of firewalls:
When you enable SSL, stateful inspection firewalls behave like application proxy firewalls because they do not decrypt encrypted packets.
Firewalls do not inspect encrypted traffic. When a firewall encounters data addressed to an SSL port on an intranet server, it checks the target IP address against its access rules and lets the SSL packet pass through to permitted SSL ports, rejecting all others.
With the Oracle Net Firewall Proxy kit, a product offered by some firewall vendors, firewall applications can provide specific support for database network traffic. If the proxy kit is implemented in the firewall, the following processing takes place:
Oracle Connection Manager lets you route client connections over multiple Oracle Net protocols. Each client connection request establishes an SSL connection between the client and Oracle Connection Manager, which in turn establishes a TCP/IP connection with the target database. Multiple clients can thus connect to multiple databases behind the firewall, using a single SSL port through the firewall.
| See Also:
Oracle Net Services Administrator's Guide for information about Oracle Connection Manager |
Consider the following issues when using SSL:
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Note:
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See Also:
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To enable SSL:
Install Oracle Advanced Security on both the client and server. When you do this, the Oracle Universal Installer automatically installs SSL libraries and Oracle Wallet Manager on your system.
During installation, Oracle sets defaults on both the Oracle database server and on the Oracle client for all SSL parameters except the location of the Oracle wallet. To configure SSL on the server, perform these steps:
| See Also:
Appendix B, "Authentication Parameters" for the dynamic parameter names |
Before proceeding with the next step, you must confirm that a wallet has been created. To confirm that your wallet is ready, open it by using Oracle Wallet Manager. The wallet should contain a certificate with a status of "Ready" and auto login turned on. If auto login is not on, then select it from the Wallet menu and re-save the wallet. This turns auto login on.
Use Oracle Net Manager to specify required configuration parameters for the server (See "Starting Oracle Net Manager"):
Note that if you are configuring the database-to-directory SSL connection for Enterprise User Security, then Database Configuration Assistant automatically creates a database wallet while registering the database with the directory. You must use that wallet to store the database PKI credentials for SSL-authenticated Enterprise User Security.
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Important:
Be sure to enter the same wallet location when you create it and when you set the location in the |
The sqlnet.ora and listener.ora files are updated with the following entries:
wallet_location = (SOURCE= (METHOD=File) (METHOD_DATA= (DIRECTORY=wallet_location)))
A cipher suite is a set of authentication, encryption, and data integrity algorithms used for exchanging messages between network entities. During an SSL handshake, two entities negotiate to see which cipher suite they will use when transmitting messages back and forth.
When you install Oracle Advanced Security, the SSL cipher suites listed in Table 7-1 are set for you by default and negotiated in the order they are listed. You can override the default order by setting the SSL_CIPHER_SUITES parameter. For example, if you use Oracle Net Manager to add the cipher suite SSL_RSA_WITH_RC4_128_SHA, all other cipher suites in the default setting are ignored.
You can prioritize the cipher suites. When the client negotiates with servers regarding which cipher suite to use, it follows the prioritization you set. When you prioritize the cipher suites, consider the following:
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Note: If you set a cipher suite employing Diffie-Hellman anonymous authentication on the server, then you must also set the same cipher suite on the client. Otherwise, the connection fails. If you use a cipher suite employing Diffie-Hellman anonymous, then you must set the |
Table 7-1 lists the SSL cipher suites supported in the current release of Oracle Advanced Security. These cipher suites are set by default when you install Oracle Advanced Security. This table also lists the authentication, encryption, and data integrity types each cipher suite uses.
| Cipher Suites | Authentication | Encryption | Data Integrity |
|---|---|---|---|
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SSL_RSA_WITH_3DES_EDE_CBC_SHA |
RSA |
3DES EDE CBC |
SHA-1 |
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SSL_RSA_WITH_RC4_128_SHA |
RSA |
RC4 128 |
SHA-1 |
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SSL_RSA_WITH_RC4_128_MD5 |
RSA |
RC4 128 |
MD5 |
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SSL_RSA_WITH_DES_CBC_SHA |
RSA |
DES CBC |
SHA-1 |
|
SSL_DH_anon_WITH_3DES_EDE_CBC_SHA |
DH anon |
3DES EDE CBC |
SHA-1 |
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SSL_DH_anon_WITH_RC4_128_MD5 |
DH anon |
RC4 128 |
MD5 |
|
SSL_DH_anon_WITH_DES_CBC_SHA |
DH anon |
DES CBC |
SHA-1 |
|
SSL_RSA_EXPORT_WITH_RC4_40_MD5 |
RSA |
RC4 40 |
MD5 |
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SSL_RSA_EXPORT_WITH_DES40_CBC_SHA |
RSA |
DES40 CBC |
SHA-1 |
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SSL_RSA_WITH_AES_128_CBC_SHAFoot 1 |
RSA |
AES 128 CBC |
SHA-1 |
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SSL_RSA_WITH_AES_256_CBC_SHAFootref 1 |
RSA |
AES 256 CBC |
SHA-1 |
| 1 AES ciphers work with Transport Layer Security (TLS 1.0) only |
Text description of the illustration ssl0002.gif
Text description of the illustration ssl0004.gif
The sqlnet.ora file is updated with the following entry:
SSL_CIPHER_SUITES= (SSL_cipher_suite1 [,SSL_cipher_suite2])
You can set the SSL_VERSION parameter in the sqlnet.ora file. This parameter defines the version of SSL that must run on the systems with which the server communicates. You can require these systems to use any valid version. The default setting for this parameter in sqlnet.ora is undetermined, which is set by selecting Any from the list in the SSL tab of the Oracle Advanced Security window.
If you chose Any, then the sqlnet.ora file is updated with the following entry:
SSL_VERSION=UNDETERMINED
The SSL_CLIENT_AUTHENTICATION parameter in the sqlnet.ora file controls whether the client is authenticated using SSL. The default value is TRUE.
You must set this parameter to FALSE if you are using a cipher suite that contains Diffie-Hellman anonymous authentication (DH_anon). Also, you can set this parameter to FALSE for the client to authenticate itself to the server by using any of the non-SSL authentication methods supported by Oracle Advanced Security, such as Kerberos or RADIUS.
Text description of the illustration ssl0005.gif
The sqlnet.ora file is updated with the following entry:
SSL_CLIENT_AUTHENTICATION=FALSE
The SQLNET.AUTHENTICATION_SERVICES parameter in the sqlnet.ora file sets the SSL authentication service.
Set this parameter if you want to use SSL authentication in conjunction with another authentication method supported by Oracle Advanced Security. For example, use this parameter if you want the server to authenticate itself to the client by using SSL and the client to authenticate itself to the server by using Kerberos.
Add TCP/IP with SSL (TCPS) to this parameter in the sqlnet.ora file by using a text editor. For example, if you want to use SSL authentication in conjunction with RADIUS authentication, set this parameter as follows:
SQLNET.AUTHENTICATION_SERVICES = (TCPS, radius)
If you do not want to use SSL authentication in conjunction with another authentication method, then do not set this parameter.
Configure the listener with a TCP/IP with SSL listening endpoint in the listener.ora file. Oracle Corporation recommends using port number 2484 for typical Oracle Net clients.
See Also:
|
To configure SSL on the client:
| See Also:
Appendix B, "Authentication Parameters", for the dynamic parameter names. |
Before proceeding with the next step, you must confirm that a wallet has been created on the client and that the client has a valid certificate.
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Note: Oracle Corporation recommends that you use Oracle Wallet Manager to remove the trusted certificate in your Oracle wallet associated with each certificate authority that you do not use. |
See Also:
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You must specify the server's distinguished name (DN) and TCPS as the protocol in the client network configuration files to enable server DN matching and TCP/IP with SSL connections. Server DN matching prevents the database server from faking its identity to the client during connections by matching the server's global database name against the DN from the server certificate.
You must manually edit the client network configuration files, tnsnames.ora and listener.ora, to specify the server's DN and the TCP/IP with SSL protocol. The tnsnames.ora file can be located on the client or in the LDAP directory. If it is located on the client, then it typically resides in the same directory as the listener.ora file. Depending on your operating system, these files reside in the following directory locations:
To edit the tnsnames.ora and listener.ora files, use the following steps:
tnsnames.ora file, add the SSL_SERVER_CERT_DN parameter and specify the database server's DN as follows:
(SECURITY=
(SSL_SERVER_CERT_DN="cn=finance,cn=OracleContext,c=us,o=acme"))
The client uses this information to obtain the list of DNs it expects for each of the servers, enforcing the server's DN to match its service name. Example 7-1 shows an entry for the Finance database in the tnsnames.ora file.
Alternatively, the administrator can ensure that the common name (CN) portion of the server's DN matches the service name.
tnsnames.ora file, enter tcps as the PROTOCOL in the ADDRESS parameter. This specifies that the client will use TCP/IP with SSL to connect to the database that is identified in the SERVICE_NAME parameter. Example 7-1 also shows an entry that specifies TCP/IP with SSL as the connecting protocol in the tnsnames.ora file.listener.ora file, enter tcps as the PROTOCOL in the ADDRESS parameter. Example 7-2 shows an entry that specifies TCP/IP with SSL as the protocol.finance= (DESCRIPTION= (ADDRESS_LIST=
(ADDRESS= (PROTOCOL = tcps) (HOST = finance_server) (PORT = 1575)))
(CONNECT_DATA=
(SERVICE_NAME= Finance.us.acme.com))
(SECURITY=
(SSL_SERVER_CERT_DN="cn=finance,cn=OracleContext,c=us,o=acme"))
LISTENER= (DESCRIPTION_LIST=
(DESCRIPTION=
(ADDRESS= (PROTOCOL = tcps) (HOST = finance_server) (PORT = 1575))))
Use Oracle Net Manager to specify required configuration parameters for the client (See "Starting Oracle Net Manager"):
Text description of the illustration ssl0001.gif
The sqlnet.ora file on the client is updated with the following entries:
SSL_CLIENT_AUTHENTICATION =TRUE wallet_location = (SOURCE= (METHOD=File) (METHOD_DATA= (DIRECTORY=wallet_location))) SSL_SERVER_DN_MATCH=(ON/OFF)
A cipher suite is a set of authentication, encryption, and data integrity algorithms used for exchanging messages between network entities. During an SSL handshake, two entities negotiate to see which cipher suite they will use when transmitting messages back and forth.
When you install Oracle Advanced Security,the SSL cipher suites listed in Table 7-1 are set for you by default. This table lists them in the order they are tried when two entities are negotiating a connection. You can override the default by setting the SSL_CIPHER_SUITES parameter. For example, if you use Oracle Net Manager to add the cipher suite SSL_RSA_WITH_RC4_128_SHA, all other cipher suites in the default setting are ignored.
You can prioritize the cipher suites. When the client negotiates with servers regarding which cipher suite to use, it follows the prioritization you set. When you prioritize the cipher suites, consider the following:
The cipher suites selected for a client must be compatible with those required by the server. For example, in the case of an Oracle Call Interface (OCI) user, the server requires the client to authenticate itself. You cannot, in this case, use a cipher suite employing Diffie-Hellman anonymous authentication which disallows the exchange of certificates.
You typically prioritize cipher suites starting with the strongest and moving to the weakest.
Table 7-1 lists the SSL cipher suites supported in the current release of Oracle Advanced Security. These cipher suites are set by default when you install Oracle Advanced Security. This table also lists the authentication, encryption, and data integrity types each cipher suite uses.
Text description of the illustration ssl0003.gif
The sqlnet.ora file is updated with the following entry:
SSL_CIPHER_SUITES= (SSL_cipher_suite1 [,SSL_cipher_suite2])
You can set the SSL_VERSION parameter in the sqlnet.ora file. This parameter defines the version of SSL that must run on the systems with which the client communicates. You can require these systems to use any valid version. The default setting for this parameter in sqlnet.ora is undetermined, which is set by selecting Any from the list in the SSL tab of the Oracle Advanced Security window. When Any is selected, TLS 1.0 is tried first, then SSL 3.0 and SSL 2.0 are tried in that order. Ensure that the client SSL version is compatible with the version the server uses.
The sqlnet.ora file is updated. If you selected Any, then it is updated with the following entry:
SSL_VERSION=UNDETERMINED
The SQLNET.AUTHENTICATION_SERVICES parameter in the sqlnet.ora file sets the SSL authentication service. Typically, the sqlnet.ora file is located in the same directory as the other network configuration files. Depending on your platform, the sqlnet.ora file is in the following directory location:
Set the SQLNET.AUTHENTICATION_SERVICES parameter if you want to use SSL authentication in conjunction with another authentication method supported by Oracle Advanced Security. For example, use this parameter if you want the server to authenticate itself to the client by using SSL and the client to authenticate itself to the server by using RADIUS.
Add TCP/IP with SSL (TCPS) to this parameter in the sqlnet.ora file by using a text editor. For example, if you want to use SSL authentication in conjunction with RADIUS authentication, set this parameter as follows:
SQLNET.AUTHENTICATION_SERVICES = (TCPS, radius)
If you do not want to use SSL authentication in conjunction with another authentication method, then do not set this parameter.
If you are using SSL authentication for the client (SSL_CLIENT_AUTHENTICATION=true in the listener.ora file), then launch SQL*Plus and enter the following:
CONNECT/@net_service_name
If you are not using SSL authentication (SSL_CLIENT_AUTHENTICATION=false in the listener.ora file), launch SQL*Plus and enter the following:
CONNECT username/password@net_service_name
| See Also:
"Certificate Validation with Certificate Revocation Lists" for information about configuring the client for certificate validation with certificate revocation lists |
The following section lists the most common errors you may receive while using the Oracle Advanced Security SSL adapter.
It may be necessary to enable Oracle Net tracing to determine the cause of an error. For information about setting tracing parameters to enable Oracle Net tracing, see Oracle Net Services Administrator's Guide.
Cause: The system could not open the specified file. Typically, this error occurs because the wallet cannot be found.
Action: Check the following:
sqlnet.ora file. Note: this should be the same directory location where you saved the wallet.Cause: An incorrect password was used to decrypt an encrypted private key. Frequently, this happens because an auto login wallet is not being used.
Action: Use Oracle Wallet Manager to turn the auto login feature on for the wallet. Then re-save the wallet. See "Using Auto Login".
Cause: This is a generic error that can occur during SSL handshake negotiation between two processes.
Action: Enable Oracle Net tracing and attempt the connection again to produce trace output. Then contact Oracle customer support with the trace output.
Cause: An error occurred during the negotiation between two processes as part of the SSL protocol. This error can occur when two sides of the connection do not support a common cipher suite.
Action: Check the following:
Cause: This error occurred because the peer closed the connection.
Action: Check the following:
sqlnet.ora file so the system can find the wallet.sqlnet.ora file. (Sometimes this error occurs because the sqlnet.ora has been manually edited and the cipher suite names are misspelled. Note that case sensitive string matching is used with cipher suite names.)Cause: The SSL connection closed because of an error in the underlying transport layer, or because the peer process quit unexpectedly.
Action: Check the following:
SSL_CLIENT_AUTHENTICATION parameter is set to true in the server's listener.ora file, then the client does not pass its certificate to the server. When the server does not receive the client's certificate, it (the server) cannot authenticate the client so the connection is closed. To resolve this use another cipher suite, or set this listener.ora parameter to false.Cause: When the peer presented the certificate chain, it was checked and that check failed. This failure can be caused by a number of problems, including:
Action: See "Opening an Existing Wallet" to use Oracle Wallet Manager to open your wallet and check the following:
Cause: Your certificate was not created with the appropriate X.509 Version 3 key usage extension.
Action: Use Oracle Wallet Manager to check the certificate's key usage. See Table 8-1, "KeyUsage Values".
Cause: The certificate sent by the other side could not be validated. This may occur if the certificate has expired, has been revoked, or is invalid for another reason.
Action: Check the following:
Cause: A certificate chain cannot be created with the existing trust points for the certificate being installed. Typically, this error is returned when the peer does not give the complete chain and you do not have the appropriate trust points to complete it.
Action: Use Oracle Wallet Manager to install the trust points that are required to complete the chain. See "Importing a Trusted Certificate"
The process of determining whether a given certificate can be used in a given context is referred to as certificate validation. Certificate validation includes determining that
The SSL network layer automatically performs the first three validation checks, but you must configure certificate revocation list (CRL) checking to ensure that certificates have not been revoked. CRLs are signed data structures that contain a list of revoked certificates. They are usually issued and signed by the same entity who issued the original certificate. (See certificate revocation lists)
This section contains the following topics:
You should have CRLs for all of the trust points that you honor. The trust points are the trusted certificates from a third party identity that is qualified with a level of trust. Typically, the certificate authorities you trust are called trust points.
Certificate revocation status is checked against CRLs which are located in file system directories, Oracle Internet Directory, or downloaded from the location specified in the CRL Distribution Point (CRL DP) extension on the certificate. Typically, CRL definitions are valid for a few days. If you store your CRLs on the local file system or in the directory, then you must update them regularly. If you use CRL DPs then CRLs are downloaded each time a certificate is used so there is no need to regularly refresh the CRLs.
The server searches for CRLs in the following locations in the order listed. When the system finds a CRL that matches the certificate CA's DN, it stops searching.
The system checks the sqlnet.ora file for the SSL_CRL_FILE parameter first, followed by the SSL_CRL_PATH parameter. If these two parameters are not specified, then the system checks the wallet location for any CRLs.
Note: if you store CRLs on your local file system, then you must use the orapki utility to periodically update them. See "Renaming CRLs with a Hash Value for Certificate Validation"
If the server cannot locate the CRL on the local file system and directory connection information has been configured in an ldap.ora file, then the server searches in the directory. It searches the CRL subtree by using the CA's distinguished name (DN) and the DN of the CRL subtree.
See "To create an ldap.ora file for your Oracle home:" (The server must have a properly configured ldap.ora file to search for CRLs in the directory. It cannot use the Domain Name System (DNS) discovery feature of Oracle Internet Directory.) Also note that if you store CRLs in the directory, then you must use the orapki utility to periodically update them. See "Uploading CRLs to Oracle Internet Directory"
If the CA specifies a location in the CRL DP X.509, version 3, certificate extension when the certificate is issued, then the appropriate CRL that contains revocation information for that certificate is downloaded. Currently, Oracle Advanced Security supports downloading CRLs over HTTP and LDAP.
The SSL_CERT_REVOCATION parameter must be set to REQUIRED or REQUESTED in the sqlnet.ora file to enable certificate revocation status checking. By default this parameter is set to NONE indicating that certificate revocation status checking is turned off.
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Note: If you want to store CRLs on your local file system or in Oracle Internet Directory, then you must use the command line utility, |
Text description of the illustration ssl0006.gif
Requires certificate revocation status checking. The SSL connection is rejected if a certificate is revoked or no CRL is found. SSL connections are accepted only if it can be verified that the certificate has not been revoked.
Performs certificate revocation status checking if a CRL is available. The SSL connection is rejected if a certificate is revoked. SSL connections are accepted if no CRL is found or if the certificate has not been revoked.
Enter the path to the directory where CRLs are stored, or click Browse to find it by searching the file system. Specifying this path sets the SSL_CRL_PATH parameter in the sqlnet.ora file. If a path is not specified for this parameter, then the default is the wallet directory. Both DER-encoded (binary format) and PEM-encoded (BASE64) CRLs are supported.
Enter the path to a comprehensive CRL file (where PEM-encoded (BASE64) CRLs are concatenated in order of preference in one file), or click Browse to find it by searching the file system. Specifying this file sets the SSL_CRL_FILE parameter in the sqlnet.ora file. If this parameter is set, then the file must be present in the specified location, or else the application will error out during startup.
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Note: If you want to store CRLs in a local file system directory by setting the Certificate Revocation Lists Path, then you must use the |
ldap.ora file. See "To create an ldap.ora file for your Oracle home:"
sqlnet.ora file is updated with the following entry:
SSL_CERT_REVOCATION=NONE
| See Also:
"Troubleshooting Certificate Validation" for information about resolving certificate validation errors. |
Before you can enable certificate revocation status checking, you must ensure that the CRLs you receive from the CAs you use are in a form (renamed with a hash value) or in a location (uploaded to the directory) where your system can use them. Oracle Advanced Security provides a command-line utility, orapki, that you can use to perform the following tasks:
You can also use LDAP command-line tools to manage CRLs in Oracle Internet Directory.
| See Also:
Appendix A, "Syntax for Command-Line Tools" in Oracle Internet Directory Application Developer's Guide for information about LDAP command-line tools and their syntax. |
You can display all the orapki commands that are available for managing CRLs by entering the following at the command line:
orapki crl help
This command displays all available CRL management commands and their options.
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Note: Using the |
When the system validates a certificate, it must locate the CRL issued by the CA who created the certificate. The system locates the appropriate CRL by matching the issuer name in the certificate with the issuer name in the CRL.
When you specify a CRL storage location for the Certificate Revocation Lists Path field in Oracle Net Manager (sets the SSL_CRL_PATH parameter in the sqlnet.ora file), use the orapki utility to rename CRLs with a hash value that represents the issuer's name. Creating the hash value enables the server to load the CRLs.
On UNIX operating systems, orapki creates a symbolic link to the CRL. On Windows operating systems, it creates a copy of the CRL file. In either case, the symbolic link or the copy created by orapki are named with a hash value of the issuer's name. Then when the system validates a certificate, the same hash function is used to calculate the link (or copy) name so the appropriate CRL can be loaded.
Depending on your operating system, enter one of the following commands to rename CRLs stored in the file system.
orapki crl hash -crl crl_filename [-wallet wallet_location] -symlink crl_ directory [-summary]
orapki crl hash -crl crl_filename [-wallet wallet_location] -copy crl_directory [-summary]
where crl_filename is the name of the CRL file, wallet_location is the location of a wallet that contains the certificate of the CA that issued the CRL, and crl_directory is the directory where the CRL is located.
Using -wallet and -summary are optional. Specifying -wallet causes the tool to verify the validity of the CRL against the CA's certificate prior to renaming the CRL. Specifying the -summary option causes the tool to display the CRL issuer's name.
Publishing CRLs in the directory enables CRL validation throughout your enterprise, eliminating the need for individual applications to configure their own CRLs. All applications can use the CRLs stored in the directory where they can be centrally managed, greatly reducing the administrative overhead of CRL management and use.
The user who uploads CRLs to the directory by using orapki must be a member of the directory group CRLAdmins (cn=CRLAdmins,cn=groups,%s_OracleContextDN%). This is a privileged operation because these CRLs are accessible to the entire enterprise. Contact your directory administrator to be added to this administrative directory group.
orapki crl upload -crl crl_location -ldap hostname:ssl_port -user username [-wallet wallet_location] [-summary]
where crl_location is the file name or URL where the CRL is located, hostname and ssl_port (SSL port with no authentication) are for the system on which your directory is installed, username is the directory user who has permission to add CRLs to the CRL subtree, and wallet_location is the location of a wallet that contains the certificate of the CA that issued the CRL.
Using -wallet and -summary are optional. Specifying -wallet causes the tool to verify the validity of the CRL against the CA's certificate prior to uploading it to the directory. Specifying the -summary option causes the tool to print the CRL issuer's name and the LDAP entry where the CRL is stored in the directory.
You can display a list of all CRLs stored in the directory with orapki, which is useful for browsing to locate a particular CRL to view or download to your local system. This command displays the CA who issued the CRL (Issuer) and its location (DN) in the CRL subtree of your directory.
orapki crl list -ldap hostname:ssl_port
where the hostname and ssl_port are for the system on which your directory is installed. Note that this is the directory SSL port with no authentication as described in the preceding section.
You can view specific CRLs that are stored in Oracle Internet Directory in a summarized format or you can request a complete listing of revoked certificates for the specified CRL. A summary listing provides the CRL issuer's name and its validity period. A complete listing provides a list of all revoked certificates contained in the CRL.
orapki crl display -crl crl_location [-wallet wallet_location] -summary
where crl_location is the location of the CRL in the directory. It is convenient to paste the CRL location from the list that displays when you use the orapki crl list command. See: "Listing CRLs Stored in Oracle Internet Directory".
orapki crl display -crl crl_location [-wallet wallet_location] -complete
For example, the following orapki command:
orapki crl display -crl $T_WORK/pki/wlt_crl/nzcrl.txt -wallet $T_WORK/pki/wlt_ crl -complete
produces the following output, which lists the CRL issuer's DN, its publication date, date of its next update, and the revoked certificates it contains:
issuer = CN=root,C=us, thisUpdate = Sun Nov 16 10:56:58 PST 2003, nextUpdate = Mon Sep 30 11:56:58 PDT 2013, revokedCertificates = {(serialNo = 153328337133459399575438325845117876415, revocationDate - Sun Nov 16 10:56:58 PST 2003)} CRL is valid
Using the -wallet option causes the orapki crl display command to validate the CRL against the CA's certificate.
Depending on the size of your CRL, choosing the -complete option may take a long time to display.
You can also use Oracle Directory Manager, a graphical user interface tool that is provided with Oracle Internet Directory, to view CRLs in the directory. CRLs are stored in the following directory location:
cn=CRLValidation,cn=Validation,cn=PKI,cn=Products,cn=OracleContext
The user who deletes CRLs from the directory by using orapki must be a member of the directory group CRLAdmins. See "Uploading CRLs to Oracle Internet Directory" for information about this directory administrative group.
orapki crl delete -issuer issuer_name -ldap host:ssl_port -user username [-summary]
where issuer_name is the name of the CA who issued the CRL, the hostname and ssl_port are for the system on which your directory is installed, and username is the directory user who has permission to delete CRLs from the CRL subtree. Note that this must be a directory SSL port with no authentication. See "Uploading CRLs to Oracle Internet Directory" for more information about this port.
Using the -summary option causes the tool to print the CRL LDAP entry that was deleted.
For example, the following orapki command:
orapki crl delete -issuer "CN=root,C=us" -ldap machine1:3500 -user cn=orcladmin -summary
produces the following output, which lists the location of the deleted CRL in the directory:
Deleted CRL at cn=root cd45860c.rN,cn=CRLValidation,cn=Validation,cn=PKI,cn=Products,cn=OracleContext
To determine whether certificates are being validated against CRLs, you can enable Oracle Net tracing. When a revoked certificate is validated by using CRLs, then you will see the following entries in the Oracle Net tracing file without error messages logged between entry and exit:
nzcrlVCS_VerifyCRLSignature: entry nzcrlVCS_VerifyCRLSignature: exit nzcrlVCD_VerifyCRLDate: entry nzcrlVCD_VerifyCRLDate: exit nzcrlCCS_CheckCertStatus: entry nzcrlCCS_CheckCertStatus: Certificate is listed in CRL nzcrlCCS_CheckCertStatus: exit
Note that when certificate validation fails, the peer in the SSL handshake sees an ORA-29024: Certificate Validation Failure. If this message displays, see "ORA-29024: Certificate Validation Failure" for information about how to resolve the error.
| See Also:
Oracle Net Services Administrator's Guide for information about setting tracing parameters to enable Oracle Net tracing |
The following trace messages, relevant to certificate validation, may be logged between the entry and exit entries in the Oracle Net tracing file. Oracle SSL looks for CRLs in multiple locations, so there may be multiple errors in the trace.
Check the following list of possible error messages for information about how to resolve them.
Cause: The CRL signature cannot be verified.
Action: Ensure that the downloaded CRL is issued by the peer's CA and that the CRL was not corrupted when it was downloaded. Note that the orapki utility verifies the CRL before renaming it with a hash value or before uploading it to the directory. See "Certificate Revocation List Management" for information about using orapki for CRL management.
Cause: The current time is later than the time listed in the next update field. You should not see this error if CRL DP is used. The systems searches for the CRL in the following order:
The first CRL found in this search may not be the latest.
Action: Update the CRL with the most recent copy.
Cause: The CRL could not be found at the configured locations. This will return error ORA-29024 if the configuration specifies that certificate validation is require.
Action: Ensure that the CRL locations specified in the configuration are correct by performing the following steps:
orapki utility to configure CRLs for system use as follows:
Cause: Oracle Internet Directory (OID) connection information is not set. Note that this is not a fatal error. The search continues with CRL DP.
Action: If you want to store the CRLs in Oracle Internet Directory, then use Oracle Net Configuration Assistant to create and configure an ldap.ora file for your Oracle home. See "To create an ldap.ora file for your Oracle home:"
Cause: The CRL could not be fetched by using the CRL DP. This happens if the certificate does not have a location specified in its CRL DP extension, or if the URL specified in the CRL DP extension is incorrect.
Action: Manually download the CRL. Then depending on whether you want to store it on your local file system or in Oracle Internet Directory, perform the following steps:
If you want to store the CRL on your local file system:
orapki utility to configure the CRL for system use. See "Renaming CRLs with a Hash Value for Certificate Validation"If you want to store the CRL in Oracle Internet Directory:
ldap.ora file with directory connection information. See "To create an ldap.ora file for your Oracle home:"orapki utility to upload the CRL to the directory. See "Uploading CRLs to Oracle Internet Directory"Oracle Advanced Security supports hardware security modules that use APIs which conform to the RSA Security, Inc., PKCS #11 specification. Typically, these hardware devices are used to securely store and manage private keys in tokens or smart cards, or to accelerate cryptographic processing.
This section contains the following topics:
The following general guidelines apply if you are using a hardware security module with Oracle Advanced Security:
PKCS11 by using Oracle Wallet Manager and specify the absolute path to the PKCS #11 library (including the library name) if you wish to store the private key in the token. Oracle PKCS11 wallets contain information that points to the token for private key access.You can use the wallet containing PKCS #11 information just as you would use any Oracle wallet, except the private keys are stored on the hardware device and the cryptographic operations are performed on the device as well.
Hardware security modules made by nCipher Corporation are certified to operate with Oracle Advanced Security. These modules provide a secure way to store keys and off load cryptographic processing. Primarily, these devices provide the following benefits:
To use an nCipher hardware security module, you need the following components:
To use the secure accelerator, you must provide the absolute path to the directory that contains the nCipher PKCS #11 library (including the library name) when you create the wallet by using Oracle Wallet Manager. This enables the library to be loaded at runtime. Typically, the nCipher card is installed at the following locations:
The nCipher PKCS #11 library is located at the following file system directory locations for typical installations:
/opt/nfast/toolkits/pkcs11/libcknfast.so/opt/nfast/toolkits/pkcs11/libcknfast-64.soC:\nfast\toolkits\pkcs11\cknfast.dll
To detect whether the module is being used, you can turn on Oracle Net tracing. If the wallet contains PKCS #11 information and the private key on the module is being used, then you will see the following entries in the Oracle Net tracing file without error messages logged between entry and exit:
nzpkcs11_Init: entry nzpkcs11CP_ChangeProviders: entry nzpkcs11CP_ChangeProviders: exit nzpkcs11GPK_GetPrivateKey: entry nzpkcs11GPK_GetPrivateKey: exit nzpkcs11_Init: exit ... nzpkcs11_Decrypt: entry nzpkcs11_Decrypt: exit nzpkcs11_Sign: entry nzpkcs11_Sign: exit
| See Also:
Oracle Net Services Administrator's Guide for information about setting tracing parameters to enable Oracle Net tracing |
The following errors are associated with using PKCS #11 hardware security modules:
Cause: The system cannot locate the PKCS #11 library at the location specified when the wallet was created. This happens only when the library is moved after the wallet is created.
Action: Copy the PKCS #11 library back to its original location (where it was when the wallet was created).
Cause: The smart card that was used to create the wallet is not present in the hardware security module slot.
Action: Ensure that the smart card that was used when the wallet was created is present in the hardware security module slot.
Cause: This can occur when
Action: Depending on the cause, take one of the following actions:
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Note: The nCipher log file is in the directory where the module is installed at the following location:
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