135 lines
4.3 KiB
HTML
135 lines
4.3 KiB
HTML
<html> <head> </head> <body> <pre>
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SPAWN(8) SPAWN(8)
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<b>NAME</b>
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spawn - Postfix external command spawner
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<b>SYNOPSIS</b>
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<b>spawn</b> [generic Postfix daemon options] command_attributes...
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<b>DESCRIPTION</b>
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The <b>spawn</b> daemon provides the Postfix equivalent of <b>inetd</b>.
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It listens on a port as specified in the Postfix <b>master.cf</b>
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file and spawns an external command whenever a connection
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is established. The connection can be made over local IPC
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(such as UNIX-domain sockets) or over non-local IPC (such
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as TCP sockets). The command's standard input, output and
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error streams are connected directly to the communication
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endpoint.
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This daemon expects to be run from the <a href="master.8.html"><b>master</b>(8)</a> process
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manager.
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<b>COMMAND</b> <b>ATTRIBUTE</b> <b>SYNTAX</b>
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The external command attributes are given in the <b>master.cf</b>
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file at the end of a service definition. The syntax is as
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follows:
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<b>user</b>=<i>username</i> (required)
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<b>user</b>=<i>username</i>:<i>groupname</i>
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The external command is executed with the rights of
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the specified <i>username</i>. The software refuses to
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execute commands with root privileges, or with the
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privileges of the mail system owner. If <i>groupname</i>
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is specified, the corresponding group ID is used
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instead of the group ID of of <i>username</i>.
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<b>argv</b>=<i>command</i>... (required)
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The command to be executed. This must be specified
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as the last command attribute. The command is exe-
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cuted directly, i.e. without interpretation of
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shell meta characters by a shell command inter-
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preter.
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<b>BUGS</b>
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In order to enforce standard Postfix process resource con-
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trols, the <b>spawn</b> daemon runs only one external command at
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a time. As such, it presents a noticeable overhead by
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wasting precious process resources. The <b>spawn</b> daemon is
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expected to be replaced by a more structural solution.
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<b>DIAGNOSTICS</b>
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The <b>spawn</b> daemon reports abnormal child exits. Problems
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are logged to <b>syslogd</b>(8).
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<b>SECURITY</b>
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This program needs root privilege in order to execute
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1
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SPAWN(8) SPAWN(8)
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external commands as the specified user. It is therefore
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security sensitive. However the <b>spawn</b> daemon does not
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talk to the external command and thus is not vulnerable to
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data-driven attacks.
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<b>CONFIGURATION</b> <b>PARAMETERS</b>
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The following <b>main.cf</b> parameters are especially relevant
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to this program. See the Postfix <b>main.cf</b> file for syntax
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details and for default values. Use the <b>postfix</b> <b>reload</b>
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command after a configuration change.
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<b>Miscellaneous</b>
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<b>export</b><i>_</i><b>environment</b>
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List of names of environment parameters that can be
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exported to non-Postfix processes.
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<b>mail</b><i>_</i><b>owner</b>
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The process privileges used while not running an
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external command.
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<b>Resource</b> <b>control</b>
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<i>service_</i><b>command</b><i>_</i><b>time</b><i>_</i><b>limit</b>
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The amount of time the command is allowed to run
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before it is killed with force. The <i>service</i> name is
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the name of the entry in the <b>master.cf</b> file. The
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default time limit is given by the global <b>com-</b>
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<b>mand</b><i>_</i><b>time</b><i>_</i><b>limit</b> configuration parameter.
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<b>SEE</b> <b>ALSO</b>
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<a href="master.8.html">master(8)</a> process manager
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syslogd(8) system logging
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<b>LICENSE</b>
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The Secure Mailer license must be distributed with this
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software.
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<b>AUTHOR(S)</b>
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Wietse Venema
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IBM T.J. Watson Research
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P.O. Box 704
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Yorktown Heights, NY 10598, USA
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</pre> </body> </html>
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