ProFTPD module mod_wrap2_sql

This mod_wrap2 submodule is contained in the mod_wrap2_sql.c file, and is not compiled by default. See the mod_wrap2 installation instructions.

This submodule provides the SQL database "driver" for storing IP/DNS-based access control information in SQL tables.


Please contact TJ Saunders <tj at> with any questions, concerns, or suggestions regarding this module.

SQL Access Tables

The mod_wrap2_sql module supports the "sql" string for the source-type parameter of the WrapUserTables, WrapGroupTables, and WrapTables, configuration directives. If the "sql" source-type is used, then the source-info parameter must be as described below. Note that support for SQL-based access tables requires the use of mod_sql.

mod_wrap2_sql requires two to four SQL-related configuration directives: SQLConnectInfo, and two, possibly four, SQLNamedQuery directives. The SQLConnectInfo is necessary to allow the module to connect to the SQL database. The other directives define the SQL queries that will be used by mod_wrap2 for its retrieval operations involving access data.

When using SQL tables and mod_sql, the access tables should appear in the database named by the SQLConnectInfo directive, which will probably also contain the authentication information tables. This way your proftpd-specific tables are kept together. Also, it is probably better to use a connection policy of PERSESSION, otherwise there will be more overhead associated with each new connection made to the database for each transaction.

One SQLNamedQuery is needed to SELECT access information from the allow table, and one to SELECT access information from the deny table. These queries should return a list of words, where each word is a host name, host address, pattern, or wildcard (see here for how these things are defined). Failure to define either of these SQLNamedQuery directives will cause an error during mod_wrap2_sql's operation.

Optionally, other SQLNamedQuery directives can be defined to look up access options from the allow and deny tables.

For SQL tables, the format for the WrapUserTables, WrapGroupTables, and WrapTables directives is:

  WrapTables sql:/allow-SQLNamedQuery[/allow-options-SQLNamedQuery] \
where the allow-options-SQLNamedQuery and deny-options-SQLNamedQuery portions of the string are optional.

SQL Access Tables Example
Here are example SQLNamedQuery directives to help demonstrate how the mod_sql hooks are used by mod_wrap2. These example SQL statements assume the existence of two tables: a wrapallow table that defines allowed clients, and a wrapdeny table that defines the denied clients.

  SQLNamedQuery get-allowed-clients SELECT "allowed FROM wrapallow WHERE name = '%{0}'"
  SQLNamedQuery get-denied-clients SELECT "denied FROM wrapdeny WHERE name = '%{0}'"
  SQLNamedQuery get-all-allowed-clients SELECT "allowed FROM wrapallow"
  SQLNamedQuery get-all-denied-clients SELET "denied FROM wrapdeny"
These define the SQL statements to return the required list of words. The %{0} meta sequence will be substituted with the name being looked up (e.g. user name for WrapUserTables, primary group name for WrapGroupTables, or the empty string for WrapTables). If the administrator wants to make use of access options, then queries for those options would need to be similarly defined:
  SQLNamedQuery get-allowed-options SELECT "options FROM wrapallow WHERE name = '%{0}'"
  SQLNamedQuery get-denied-options SELECT "options FROM wrapdeny WHERE name = '%{0}'"

Now, using the above defined queries, the table configuration directives would be:

  # Access tables for users (with options)
  WrapUserTables user1,user2 sql:/get-allowed-clients/get-allowed-options \

  # Access tables for groups (with options).  Note that this directive
  # uses the same SELECT queries used for looking up users.  If group
  # access information is in a different table, then separate group-specific
  # SQLNamedQuery directives will need to be used.
  WrapGroupTables group1,group2 sql:/get-allowed-clients/get-allowed-options \

  # Access tables for everyone else (without options).  Note that these
  # query names are different, since these tables are global, not
  # per-user/group.
  WrapTables sql:/get-all-allowed-clients sql:/get-all-denied-clients
One thing to keep in mind, however, is that the %{0} part of an SQL query will only be expanded with the client's USER argument for WrapUserTables queries. For WrapGroupTables queries, that %{0} will be expanded to contain the primary group name of the connecting client's USER. For WrapTables queries, an empty string is used. This means that the same query cannot often be easily reused.

Example Schema
Here are some example table schema for SQL-based access tables:

When constructing the client and options lists to return to mod_wrap2's access control engine, mod_wrap2_sql will parse each returned row separately, handling both comma- and space-limited names in a row, into client list items. This means that the administrator can store multiple client and option tokens in multiple rows, as in the above schema, or the administrator can choose to store all of the clients and/or options in a single row, in an appropriately formatted string.

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