sslinfo
sslinfo
The sslinfo> module provides information about the SSL
certificate that the current client provided when connecting to
PostgreSQL>. The module is useless (most functions
will return NULL) if the current connection does not use SSL.
This extension won't build at all unless the installation was
configured with --with-openssl>.
Functions Provided
ssl_is_used() returns boolean
Returns TRUE if current connection to server uses SSL, and FALSE
otherwise.
ssl_client_cert_present() returns boolean
Returns TRUE if current client has presented a valid SSL client
certificate to the server, and FALSE otherwise. (The server
might or might not be configured to require a client certificate.)
ssl_client_serial() returns numeric
Returns serial number of current client certificate. The combination of
certificate serial number and certificate issuer is guaranteed to
uniquely identify a certificate (but not its owner — the owner
ought to regularly change his keys, and get new certificates from the
issuer).
So, if you run your own CA and allow only certificates from this CA to
be accepted by the server, the serial number is the most reliable (albeit
not very mnemonic) means to identify a user.
ssl_client_dn() returns text
Returns the full subject of the current client certificate, converting
character data into the current database encoding. It is assumed that
if you use non-ASCII characters in the certificate names, your
database is able to represent these characters, too. If your database
uses the SQL_ASCII encoding, non-ASCII characters in the name will be
represented as UTF-8 sequences.
The result looks like /CN=Somebody /C=Some country/O=Some organization>.
ssl_issuer_dn() returns text
Returns the full issuer name of the current client certificate, converting
character data into the current database encoding. Encoding conversions
are handled the same as for ssl_client_dn>.
The combination of the return value of this function with the
certificate serial number uniquely identifies the certificate.
This function is really useful only if you have more than one trusted CA
certificate in your server's root.crt> file, or if this CA
has issued some intermediate certificate authority certificates.
ssl_client_dn_field(fieldname text) returns text
This function returns the value of the specified field in the
certificate subject, or NULL if the field is not present.
Field names are string constants that are
converted into ASN1 object identifiers using the OpenSSL object
database. The following values are acceptable:
commonName (alias CN)
surname (alias SN)
name
givenName (alias GN)
countryName (alias C)
localityName (alias L)
stateOrProvinceName (alias ST)
organizationName (alias O)
organizationUnitName (alias OU)
title
description
initials
postalCode
streetAddress
generationQualifier
description
dnQualifier
x500UniqueIdentifier
pseudonym
role
emailAddress
All of these fields are optional, except commonName>.
It depends
entirely on your CA's policy which of them would be included and which
wouldn't. The meaning of these fields, however, is strictly defined by
the X.500 and X.509 standards, so you cannot just assign arbitrary
meaning to them.
ssl_issuer_field(fieldname text) returns text
Same as ssl_client_dn_field>, but for the certificate issuer
rather than the certificate subject.
Author
Victor Wagner vitus@cryptocom.ru, Cryptocom LTD
E-Mail of Cryptocom OpenSSL development group:
openssl@cryptocom.ru