milter-length/0.9
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| text!/path/map.txt | R/O text file, memory hash |
| /path/map.db | Berkeley DB hash format |
| db!/path/map.db | Berkeley DB hash format |
| db!btree!/path/map.db | Berkeley DB btree format |
| sql!/path/database | An SQLite3 database |
| socketmap!host:port | Sendmail style socket-map |
| socketmap!/path/local/socket | Sendmail style socket-map |
| socketmap!123.45.67.89:port | Sendmail style socket-map |
| socketmap![2001:0DB8::1234]:port | Sendmail style socket-map |
If :port is omitted, the default is 7953.
The access-db contains key-value pairs. Lookups are performed from most to least specific, stopping on the first entry found. Keys are case-insensitive.
An IPv4 lookup is repeated several times reducing the IP address by one octet from right to left until a match is found.
tag:192.0.2.9 tag:192.0.2 tag:192.0 tag:192
An IPv6 lookup is repeated several times reducing the IP address by one 16-bit word from right to left until a match is found.
tag:2001:0DB8:0:0:0:0:1234:5678 tag:2001:0DB8:0:0:0:0:1234 tag:2001:0DB8:0:0:0:0 tag:2001:0DB8:0:0:0 tag:2001:0DB8:0:0 tag:2001:0DB8:0:0 tag:2001:0DB8:0 tag:2001:0DB8 tag:2001
A domain lookup is repeated several times reducing the domain by one label from left to right until a match is found.
tag:[ipv6:2001:0DB8::1234:5678] tag:[192.0.2.9] tag:sub.domain.tld tag:domain.tld tag:tld tag:
An email lookup is similar to a domain lookup, the exact address is first tried, then the address's domain, and finally the local part of the address.
tag:account@sub.domain.tld tag:sub.domain.tld tag:domain.tld tag:tld tag:account@ tag:
If a key is found and is a milter specific tag (ie. milter-length-Connect, milter-length-From, milter-length-Auth, milter-length-To), then the value is processed as a pattern list and the result returned. A pattern list is a whitespace separated list of pattern-size pairs followed by an optional default size. The supported patterns are:
[network/cidr]size Classless Inter-Domain Routing !pattern!size Simple fast text matching. /regex/size POSIX Extended Regular Expressions
The CIDR will only ever match for IP address related lookups.
A !pattern! uses an astrisk (*) for a wildcard, scanning over zero or more characters; a question-mark (?) matches any single character; a backslash followed by any character treats it as a literal (it loses any special meaning).
!abc! exact match for 'abc' !abc*! match 'abc' at start of string !*abc! match 'abc' at the end of string !abc*def! match 'abc' at the start and match 'def' at the end, maybe with stuff in between. !*abc*def*! find 'abc', then find 'def'
For black-white lookups, the following actions are recognised: OK or RELAY (white list), REJECT or ERROR (black list), DISCARD (accept & discard), SKIP or DUNNO (stop lookup, no result), and NEXT (opposite of SKIP, resume lookup). Its possible to specify an empty action after a pattern, which is treated like SKIP returning an undefined result. Other options may specify other actions.
Below is a list of supported tags. Other options may specify additional tags.
milter-length-Connect:client-ip value § Can be a pattern list. milter-length-Connect:[client-ip] value § Can be a pattern list. milter-length-Connect:client-domain value § Can be a pattern list. milter-length-Connect: value § Can be a pattern list. All mail sent by a connecting client-ip, unresolved client-ip address or IP addresses that resolve to a client-domain are black or white-listed. These allows you to white-list your network for mail sent internally and off-site, or connections from outside networks. milter-length-From:sender-address value § Can be a pattern list. milter-length-From:sender-domain value § Can be a pattern list. milter-length-From:sender@ value § Can be a pattern list. milter-length-From: value § Can be a pattern list. All mail from the sender-address, sender-domain, or that begins with sender is black or white-listed. In the case of a +detailed email address, the left hand side of the +detail is used for the sender@ lookup. milter-length-Auth:auth_authen value § Can be a pattern list. milter-length-Auth: value § Can be a pattern list. All mail from the authenticated sender, as given by sendmail's {auth_authen} macro, is black or white-listed. The string searched by the pattern list will be the sender-address. The empty form of milter-length-Auth: allows for a milter specific default only when {auth_authen} is defined.milter-length-To:recipient-address value § Can be a pattern list. milter-length-To:recipient-domain value § Can be a pattern list. milter-length-To:recipient@ value § Can be a pattern list. milter-length-To: value § Can be a pattern list. All mail to the recipient-address, recipient-domain, or that begins with recipient is black or white-listed. In the case of a +detailed email address, the left hand side of the +detail is used for the recipient@ lookup.
The size is the maximum number of octets permitted in a message and is expressed as a number with an optional scale suffix: K (kilo), M (mega), or G (giga). If no size is specified (or -1), then the message can be any length (ULONG_MAX).
When there are multiple message size limits assigned, then the limit applied, in order of precedence, will be: the maximum value of all relevant milter-length-to:, milter-length-auth:, milter-length-from:, milter-length-connection:, or an unlimited default. Essentially each matching milter tag replaces the previous value. When there are multiple recipients with one or more possible milter-length-to: entries, then maximum length limit found is applied.
Below are only some examples of what is possible:
milter-length-Connect:80.94 [80.94.96.0/20]2M 500K All the mail from netblock 80.94.96.0/20 (80.94.96.0 through to 80.94.111.255) is limited to 2 megabytes, while anything else in 80.94.0.0/16 is limited to 500 kilobytes. milter-length-Connect:192.0.2 10M All the mail from the network in 192.0.2.0/24 is limited to 10 megabytes. milter-length-Connect:192.0.2 /^192\.0\.2\.8[0-9]/1M 10M Mail sent from IP addresses 192.0.2.80 through to 192.0.2.89 is limited to 1 megabyte, while the rest of the network in 192.0.2.0/24 is limited to 10 megabytes.
This example is rather contrived to show some of what is possible with patterns and is the equivalent of ten simple milter-length-connect: entries. When using patterns, weigh the need vs. simplicity, readability, and administration.milter-length-From:example.com /^[^+]+@/500K Mail from within example.com, where the sender's address does not contain a plus-detail, is limited to 500 kilobytes, otherwise no limit is imposed. milter-length-To:example.net !*+*@*! /^[0-9].*/20K !*smith*@*!1M 4M Mail to addresses within example.net containing a plus-detail have no limit; those starting with a digit are limited to 20 kilobytes; mail to anyone with "smith" as part of their address is limited to 1 megabyte, while the rest of the domain is limited to 4 megabytes.
milter-length.
Typically a unix named socket or a host:port. This value must match the value specified for
the INPUT_MAIL_FILTER() macro in the sendmail.mc file. The accepted syntax is:
{unix|local}:/path/to/file- A named pipe. (default)
inet:port@{hostname|ip-address}- An IPV4 socket.
inet6:port@{hostname|ip-address}- An IPV6 socket.
kill -QUIT `cat /var/run/milter/milter-length.pid`milter-length-auth: tag (access-db=)
for finer granularity of control.
§ all All messages § 0 Log nothing. § info General info messages. (default) § trace Trace progress through the milter. § parse Details from parsing addresses or special strings. debug Lots of debug messages. dialog I/O from Communications dialog state State transitions of message body scanner. dns Trace & debug of DNS operations cache Cache get/put/gc operations. § database Sendmail database lookups. socket-fd Socket open & close calls socket-all All socket operations & I/O § libmilter libmilter engine diagnostics
SMTP Responses
This is the list of possible SMTP responses generated by milter-length.
- 550 5.7.1 max. message size \([0-9]+\) exceeded
- The message body, not counting the headers, is too big.
- 553 5.1.0 imbalanced angle brackets in path
- The path given for a MAIL or RCPT command is missing a closing angle bracket
- 553 5.1.0 address does not conform to RFC 2821 syntax
- The address is missing the angle brackets, < and >, as required by the RFC grammar.
- 553 5.1.0 local-part too long
- The stuff before the @ is too long.
- 553 5.1.[37] invalid local part
- The stuff before the @ sign contains unacceptable characters.
- 553 5.1.0 domain name too long
- The stuff after the @ is too long.
- 553 5.1.7 address incomplete
- Expecting a domain.tld after the @ sign and found none.
- 553 5.1.[37] invalid domain name
- The domain after the @ sign contains unacceptable characters.
Installation
Download:
milter-length/0.9 md5sum Change Log LibSnert md5sum Change Log Sendmail 8.13 http://www.sendmail.org/ Berkeley DB http://www.sleepycat.com/ -
In order to support the access database
milter-lengthrequires Berkeley DB. You should build and install Berkeley DB library first, if you do not already have it. Please read the Berkeley DB documentation on how to build the library. Briefly, it should be something like this:cd (path to)/db-4.2.52/build_unix ../dist/configure make make install
If your system is Linux and you install Berkeley DB in the default, non- standard, location then you must remember to update
/etc/ld.so.confand runldconfig. You can change the default install location by specifying the../dist/configureoption--prefix=/usr/localfor example. -
If you have never built a milter for Sendmail, then please make sure that you build and install
libmilter, which is not built by default when you build Sendmail prior to 8.13.0. Please read thelibmilterdocumentation. Briefly, it should be something like this:cd (path to)/sendmail-8.12.11/libmilter sh Build -c sh Build install
-
The build process for
libsnertandmilter-lengthis pretty straight forward once you havelibmilterinstalled:cd (path to)/com/snert/src/lib ./configure make build cd ../milter-length ./configure make build make install
Both configuration scripts have some options that allow you to override defaults. Those options are listed with:
./configure --help
-
An example
${prefix}/share/examples/milter-length/milter-length.mcis supplied. This file should be reviewed and the necessary elements inserted into your Sendmail.mcfile andsendmail.cfrebuilt. Please note the comments on the general milter flags.dnl ------------------------------------------------------------------- dnl milter-length.mc dnl ------------------------------------------------------------------- dnl Example configuration to be added to sendmail.mc. dnl dnl Copyright 2005, 2007 by Anthony Howe. All rights reserved. dnl dnl $OpenBSD$ dnl define(`_FFR_MILTER', `1')dnl dnl ------------------------------------------------------------------- dnl Enable this for debug output from Sendmail. dnl define(`confLOG_LEVEL', `14')dnl dnl ------------------------------------------------------------------- dnl Enable this to see even more debug output. dnl Defaults to confLOG_LEVEL. dnl dnl If Milter.LogLevel is greater-than: dnl dnl 0 Communication errors dnl 8 Header & RCPT modification messages dnl 9 Connect to info dnl 10 Milter error return codes, abort messages dnl 12 More return code info, connection/open errors dnl 14 grey & rcpts info dnl 17 Show headers & body sent to a milter. dnl 18 Quit dnl 21 Time a milter dnl define(`confMILTER_LOG_LEVEL', 14)dnl dnl ------------------------------------------------------------------- dnl The S= by default specifies a unix domain socket to be used between dnl sendmail and the milter. It can also be an Internet domain socket. dnl The accepted forms are: dnl dnl {unix|local}:/path/to/file A named pipe. (default) dnl inet:port@{hostname|ip-address} An IPv4 socket. dnl inet6:port@{hostname|ip-address} An IPv6 socket. dnl dnl Note that the F= says what to do with the message if the milter dnl is not running. dnl dnl F=T Temporary fail connection if filter unavailable dnl F=R Reject connection if filter unavailable dnl dnl If no F= specified and there is a problem with the milter, then dnl the default is to continue normal handling, skipping the milter. dnl dnl Note that the T= specifies timeouts for communication. The dnl following fields are defined: dnl dnl C Timeout for connecting to a filter. If set to zero (0), dnl the system's connect() timeout will be used. Default: 5m dnl S Timeout for sending information from the MTA to a dnl filter. Default: 10s dnl R Timeout for reading reply from the filter. Default: 10s dnl E Overall timeout between sending end-of-message to filter dnl and waiting for the final acknowledgment. Default: 5m dnl dnl So the Sendmail default values are equivalent to: dnl dnl T=C:5m;S=10s;R=10s;E:5m dnl INPUT_MAIL_FILTER( `milter-length', `S=unix:/var/run/milter/milter-length.socket, T=C:1m;S:10s;R:10s;E:1m' )dnl dnl ------------------------------------------------------------------- dnl End milter-length.mc dnl ------------------------------------------------------------------- -
Once installed and configured, start
milter-lengthand then restart Sendmail. An example startup script is provided in${prefix}/share/examples/milter-length/milter-length.sh. The default options can be altered by specifying them on the command-line or within a/etc/mail/milter-length.cf. Themilter-length.cfis parsed first followed by the command-line options.
Notes
Currently tested platforms:
Cobalt Qube 1 with Linux RH 5.1 (mips 2.0.34 kernel);Linux RH 5.1 (Intel x386 2.2.25 kernel);FreeBSD 4.8, 4.9 (Intel x386);OpenBSD 3.6 (Intel x386)-
The minimum desired file ownership and permissions are as follows for a typical Linux system. For FreeBSD, NetBSD, and OpenBSD the binary and cache locations may differ, but have the same permissions.
Process user ``milter'' is primary member of group ``milter'' and secondary member of group ``smmsp''. Note that the milter should be started as root, so that it can create a .pid file and .socket file in /var/run; after which it will switch process ownership to milter:milter before starting the accept socket thread.
/etc/mail/ root:smmsp 0750 drwxr-x--- /etc/mail/access.db root:smmsp 0640 -rw-r----- /etc/mail/sendmail.cf root:smmsp 0640 -rw-r----- /etc/mail/milter-length.cf root:root 0644 -rw-r--r-- /var/run/milter/milter-length.pid milter:milter 0644 -rw-r--r-- /var/run/milter/milter-length.socket milter:milter 0644 srw-r--r-- /var/db/milter-length milter:milter 0644 -rw-r--r-- (*BSD) /var/cache/milter-length milter:milter 0644 -rw-r--r-- (linux) /usr/local/libexec/milter-length root:milter 0550 -r-xr-x--- I would like to express my thanks to Derek Balling for his support at http://www.milter.org/.
License Agreement 1.4
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``Package'' means the identified above in source and/or binary form, any other machine readable materials provided (including, but not limited to documentation, sample files, data files), any updates or error corrections, and its derivative works.
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``You'' (or ``Your'') means a Private Individual or Organisation exercising rights under, and complying with all of the terms of, this License or a future version of this License issued under Section 5.1. For legal entities, ``You'' includes any entity which controls, is controlled by, or is under common control with You. For purposes of this definition,``control'' means (a) the power, direct or indirect, to cause the direction or management of such entity, whether by contract or otherwise, or (b) ownership of more than fifty percent (50%) of the outstanding shares or beneficial ownership of such entity.
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