caused by an incomplete API change; refined the queue space
check; release scratch space immediately after delivering
mail to the before-queue filter. Files: smtpd.c, smtpd_proxy.c.
+
+20091110
+
+ Workaround: specify "smtp_tls_block_early_mail_reply = yes"
+ to detect a mail hijacking attack based on a TLS protocol
+ vulnerability (CVE-2009-3555). The attack involves prepending
+ malicious HELO/MAIL/RCPT/DATA commands to a Postfix SMTP
+ client TLS session. The attack would succeed with non-Postfix
+ SMTP servers that reply to the malicious commands after
+ negotiating the Postfix SMTP client TLS session. File:
+ smtp/smtp_proto.c.
File with the Postfix SMTP client ECDSA private key
in PEM format.
+ Available in Postfix version 2.7 and later:
+
+ <b><a href="postconf.5.html#smtp_tls_block_early_mail_reply">smtp_tls_block_early_mail_reply</a> (no)</b>
+ Try to detect a mail hijacking attack based on a
+ TLS protocol vulnerability (CVE-2009-3555), where
+ an attacker prepends malicious HELO/MAIL/RCPT/DATA
+ commands to a Postfix client TLS session.
+
<b>OBSOLETE STARTTLS CONTROLS</b>
- The following configuration parameters exist for compati-
+ The following configuration parameters exist for compati-
bility with Postfix versions before 2.3. Support for these
will be removed in a future release.
<b><a href="postconf.5.html#smtp_use_tls">smtp_use_tls</a> (no)</b>
- Opportunistic mode: use TLS when a remote SMTP
- server announces STARTTLS support, otherwise send
+ Opportunistic mode: use TLS when a remote SMTP
+ server announces STARTTLS support, otherwise send
the mail in the clear.
<b><a href="postconf.5.html#smtp_enforce_tls">smtp_enforce_tls</a> (no)</b>
- Enforcement mode: require that remote SMTP servers
- use TLS encryption, and never send mail in the
+ Enforcement mode: require that remote SMTP servers
+ use TLS encryption, and never send mail in the
clear.
<b><a href="postconf.5.html#smtp_tls_enforce_peername">smtp_tls_enforce_peername</a> (yes)</b>
- With mandatory TLS encryption, require that the
+ With mandatory TLS encryption, require that the
remote SMTP server hostname matches the information
in the remote SMTP server certificate.
<b><a href="postconf.5.html#smtp_tls_per_site">smtp_tls_per_site</a> (empty)</b>
Optional lookup tables with the Postfix SMTP client
- TLS usage policy by next-hop destination and by
+ TLS usage policy by next-hop destination and by
remote SMTP server hostname.
<b><a href="postconf.5.html#smtp_tls_cipherlist">smtp_tls_cipherlist</a> (empty)</b>
<b>RESOURCE AND RATE CONTROLS</b>
<b><a href="postconf.5.html#smtp_destination_concurrency_limit">smtp_destination_concurrency_limit</a> ($<a href="postconf.5.html#default_destination_concurrency_limit">default_destina</a>-</b>
<b><a href="postconf.5.html#default_destination_concurrency_limit">tion_concurrency_limit</a>)</b>
- The maximal number of parallel deliveries to the
- same destination via the smtp message delivery
+ The maximal number of parallel deliveries to the
+ same destination via the smtp message delivery
transport.
<b><a href="postconf.5.html#smtp_destination_recipient_limit">smtp_destination_recipient_limit</a> ($<a href="postconf.5.html#default_destination_recipient_limit">default_destina</a>-</b>
<b><a href="postconf.5.html#default_destination_recipient_limit">tion_recipient_limit</a>)</b>
- The maximal number of recipients per message for
+ The maximal number of recipients per message for
the smtp message delivery transport.
<b><a href="postconf.5.html#smtp_connect_timeout">smtp_connect_timeout</a> (30s)</b>
- The SMTP client time limit for completing a TCP
+ The SMTP client time limit for completing a TCP
connection, or zero (use the operating system
built-in time limit).
<b><a href="postconf.5.html#smtp_helo_timeout">smtp_helo_timeout</a> (300s)</b>
- The SMTP client time limit for sending the HELO or
- EHLO command, and for receiving the initial server
+ The SMTP client time limit for sending the HELO or
+ EHLO command, and for receiving the initial server
response.
<b><a href="postconf.5.html#lmtp_lhlo_timeout">lmtp_lhlo_timeout</a> (300s)</b>
- The LMTP client time limit for sending the LHLO
+ The LMTP client time limit for sending the LHLO
command, and for receiving the initial server
response.
command, and for receiving the server response.
<b><a href="postconf.5.html#smtp_mail_timeout">smtp_mail_timeout</a> (300s)</b>
- The SMTP client time limit for sending the MAIL
- FROM command, and for receiving the server
+ The SMTP client time limit for sending the MAIL
+ FROM command, and for receiving the server
response.
<b><a href="postconf.5.html#smtp_rcpt_timeout">smtp_rcpt_timeout</a> (300s)</b>
- The SMTP client time limit for sending the SMTP
- RCPT TO command, and for receiving the server
+ The SMTP client time limit for sending the SMTP
+ RCPT TO command, and for receiving the server
response.
<b><a href="postconf.5.html#smtp_data_init_timeout">smtp_data_init_timeout</a> (120s)</b>
- The SMTP client time limit for sending the SMTP
- DATA command, and for receiving the server
+ The SMTP client time limit for sending the SMTP
+ DATA command, and for receiving the server
response.
<b><a href="postconf.5.html#smtp_data_xfer_timeout">smtp_data_xfer_timeout</a> (180s)</b>
- The SMTP client time limit for sending the SMTP
+ The SMTP client time limit for sending the SMTP
message content.
<b><a href="postconf.5.html#smtp_data_done_timeout">smtp_data_done_timeout</a> (600s)</b>
- The SMTP client time limit for sending the SMTP
+ The SMTP client time limit for sending the SMTP
".", and for receiving the server response.
<b><a href="postconf.5.html#smtp_quit_timeout">smtp_quit_timeout</a> (300s)</b>
- The SMTP client time limit for sending the QUIT
+ The SMTP client time limit for sending the QUIT
command, and for receiving the server response.
Available in Postfix version 2.1 and later:
lookups, or zero (no limit).
<b><a href="postconf.5.html#smtp_mx_session_limit">smtp_mx_session_limit</a> (2)</b>
- The maximal number of SMTP sessions per delivery
- request before giving up or delivering to a fall-
+ The maximal number of SMTP sessions per delivery
+ request before giving up or delivering to a fall-
back <a href="postconf.5.html#relayhost">relay host</a>, or zero (no limit).
<b><a href="postconf.5.html#smtp_rset_timeout">smtp_rset_timeout</a> (20s)</b>
- The SMTP client time limit for sending the RSET
+ The SMTP client time limit for sending the RSET
command, and for receiving the server response.
Available in Postfix version 2.2 and earlier:
Available in Postfix version 2.2 and later:
<b><a href="postconf.5.html#smtp_connection_cache_destinations">smtp_connection_cache_destinations</a> (empty)</b>
- Permanently enable SMTP connection caching for the
+ Permanently enable SMTP connection caching for the
specified destinations.
<b><a href="postconf.5.html#smtp_connection_cache_on_demand">smtp_connection_cache_on_demand</a> (yes)</b>
- Temporarily enable SMTP connection caching while a
+ Temporarily enable SMTP connection caching while a
destination has a high volume of mail in the active
queue.
<b><a href="postconf.5.html#smtp_connection_cache_time_limit">smtp_connection_cache_time_limit</a> (2s)</b>
When SMTP connection caching is enabled, the amount
- of time that an unused SMTP client socket is kept
+ of time that an unused SMTP client socket is kept
open before it is closed.
Available in Postfix version 2.3 and later:
<b><a href="postconf.5.html#connection_cache_protocol_timeout">connection_cache_protocol_timeout</a> (5s)</b>
- Time limit for connection cache connect, send or
+ Time limit for connection cache connect, send or
receive operations.
<b>TROUBLE SHOOTING CONTROLS</b>
<b><a href="postconf.5.html#debug_peer_level">debug_peer_level</a> (2)</b>
- The increment in verbose logging level when a
- remote client or server matches a pattern in the
+ The increment in verbose logging level when a
+ remote client or server matches a pattern in the
<a href="postconf.5.html#debug_peer_list">debug_peer_list</a> parameter.
<b><a href="postconf.5.html#debug_peer_list">debug_peer_list</a> (empty)</b>
- Optional list of remote client or server hostname
- or network address patterns that cause the verbose
- logging level to increase by the amount specified
+ Optional list of remote client or server hostname
+ or network address patterns that cause the verbose
+ logging level to increase by the amount specified
in $<a href="postconf.5.html#debug_peer_level">debug_peer_level</a>.
<b><a href="postconf.5.html#error_notice_recipient">error_notice_recipient</a> (postmaster)</b>
- The recipient of postmaster notifications about
- mail delivery problems that are caused by policy,
+ The recipient of postmaster notifications about
+ mail delivery problems that are caused by policy,
resource, software or protocol errors.
<b><a href="postconf.5.html#internal_mail_filter_classes">internal_mail_filter_classes</a> (empty)</b>
- What categories of Postfix-generated mail are sub-
- ject to before-queue content inspection by
+ What categories of Postfix-generated mail are sub-
+ ject to before-queue content inspection by
<a href="postconf.5.html#non_smtpd_milters">non_smtpd_milters</a>, <a href="postconf.5.html#header_checks">header_checks</a> and <a href="postconf.5.html#body_checks">body_checks</a>.
<b><a href="postconf.5.html#notify_classes">notify_classes</a> (resource, software)</b>
- The list of error classes that are reported to the
+ The list of error classes that are reported to the
postmaster.
<b>MISCELLANEOUS CONTROLS</b>
<b><a href="postconf.5.html#best_mx_transport">best_mx_transport</a> (empty)</b>
- Where the Postfix SMTP client should deliver mail
+ Where the Postfix SMTP client should deliver mail
when it detects a "mail loops back to myself" error
condition.
<b><a href="postconf.5.html#config_directory">config_directory</a> (see 'postconf -d' output)</b>
- The default location of the Postfix <a href="postconf.5.html">main.cf</a> and
+ The default location of the Postfix <a href="postconf.5.html">main.cf</a> and
<a href="master.5.html">master.cf</a> configuration files.
<b><a href="postconf.5.html#daemon_timeout">daemon_timeout</a> (18000s)</b>
- How much time a Postfix daemon process may take to
- handle a request before it is terminated by a
+ How much time a Postfix daemon process may take to
+ handle a request before it is terminated by a
built-in watchdog timer.
<b><a href="postconf.5.html#delay_logging_resolution_limit">delay_logging_resolution_limit</a> (2)</b>
- The maximal number of digits after the decimal
+ The maximal number of digits after the decimal
point when logging sub-second delay values.
<b><a href="postconf.5.html#disable_dns_lookups">disable_dns_lookups</a> (no)</b>
- Disable DNS lookups in the Postfix SMTP and LMTP
+ Disable DNS lookups in the Postfix SMTP and LMTP
clients.
<b><a href="postconf.5.html#inet_interfaces">inet_interfaces</a> (all)</b>
tem receives mail on.
<b><a href="postconf.5.html#inet_protocols">inet_protocols</a> (ipv4)</b>
- The Internet protocols Postfix will attempt to use
+ The Internet protocols Postfix will attempt to use
when making or accepting connections.
<b><a href="postconf.5.html#ipc_timeout">ipc_timeout</a> (3600s)</b>
over an internal communication channel.
<b><a href="postconf.5.html#lmtp_assume_final">lmtp_assume_final</a> (no)</b>
- When an LMTP server announces no DSN support,
+ When an LMTP server announces no DSN support,
assume that the server performs final delivery, and
- send "delivered" delivery status notifications
+ send "delivered" delivery status notifications
instead of "relayed".
<b><a href="postconf.5.html#lmtp_tcp_port">lmtp_tcp_port</a> (24)</b>
- The default TCP port that the Postfix LMTP client
+ The default TCP port that the Postfix LMTP client
connects to.
<b><a href="postconf.5.html#max_idle">max_idle</a> (100s)</b>
- The maximum amount of time that an idle Postfix
- daemon process waits for an incoming connection
+ The maximum amount of time that an idle Postfix
+ daemon process waits for an incoming connection
before terminating voluntarily.
<b><a href="postconf.5.html#max_use">max_use</a> (100)</b>
- The maximal number of incoming connections that a
- Postfix daemon process will service before termi-
+ The maximal number of incoming connections that a
+ Postfix daemon process will service before termi-
nating voluntarily.
<b><a href="postconf.5.html#process_id">process_id</a> (read-only)</b>
- The process ID of a Postfix command or daemon
+ The process ID of a Postfix command or daemon
process.
<b><a href="postconf.5.html#process_name">process_name</a> (read-only)</b>
- The process name of a Postfix command or daemon
+ The process name of a Postfix command or daemon
process.
<b><a href="postconf.5.html#proxy_interfaces">proxy_interfaces</a> (empty)</b>
The network interface addresses that this mail sys-
- tem receives mail on by way of a proxy or network
+ tem receives mail on by way of a proxy or network
address translation unit.
<b><a href="postconf.5.html#smtp_bind_address">smtp_bind_address</a> (empty)</b>
- An optional numerical network address that the
- Postfix SMTP client should bind to when making an
+ An optional numerical network address that the
+ Postfix SMTP client should bind to when making an
IPv4 connection.
<b><a href="postconf.5.html#smtp_bind_address6">smtp_bind_address6</a> (empty)</b>
- An optional numerical network address that the
- Postfix SMTP client should bind to when making an
+ An optional numerical network address that the
+ Postfix SMTP client should bind to when making an
IPv6 connection.
<b><a href="postconf.5.html#smtp_helo_name">smtp_helo_name</a> ($<a href="postconf.5.html#myhostname">myhostname</a>)</b>
- The hostname to send in the SMTP EHLO or HELO com-
+ The hostname to send in the SMTP EHLO or HELO com-
mand.
<b><a href="postconf.5.html#lmtp_lhlo_name">lmtp_lhlo_name</a> ($<a href="postconf.5.html#myhostname">myhostname</a>)</b>
The hostname to send in the LMTP LHLO command.
<b><a href="postconf.5.html#smtp_host_lookup">smtp_host_lookup</a> (dns)</b>
- What mechanisms when the Postfix SMTP client uses
- to look up a host's IP address.
+ What mechanisms the Postfix SMTP client uses to
+ look up a host's IP address.
<b><a href="postconf.5.html#smtp_randomize_addresses">smtp_randomize_addresses</a> (yes)</b>
- Randomize the order of equal-preference MX host
+ Randomize the order of equal-preference MX host
addresses.
<b><a href="postconf.5.html#syslog_facility">syslog_facility</a> (mail)</b>
The syslog facility of Postfix logging.
<b><a href="postconf.5.html#syslog_name">syslog_name</a> (see 'postconf -d' output)</b>
- The mail system name that is prepended to the
- process name in syslog records, so that "smtpd"
+ The mail system name that is prepended to the
+ process name in syslog records, so that "smtpd"
becomes, for example, "postfix/smtpd".
Available with Postfix 2.2 and earlier:
<b><a href="postconf.5.html#fallback_relay">fallback_relay</a> (empty)</b>
- Optional list of relay hosts for SMTP destinations
+ Optional list of relay hosts for SMTP destinations
that can't be found or that are unreachable.
Available with Postfix 2.3 and later:
<b><a href="postconf.5.html#smtp_fallback_relay">smtp_fallback_relay</a> ($<a href="postconf.5.html#fallback_relay">fallback_relay</a>)</b>
- Optional list of relay hosts for SMTP destinations
+ Optional list of relay hosts for SMTP destinations
that can't be found or that are unreachable.
<b>SEE ALSO</b>
<a href="TLS_README.html">TLS_README</a>, Postfix STARTTLS howto
<b>LICENSE</b>
- The Secure Mailer license must be distributed with this
+ The Secure Mailer license must be distributed with this
software.
<b>AUTHOR(S)</b>
<p> This feature is available in Postfix 2.2 and later. </p>
+</DD>
+
+<DT><b><a name="smtp_tls_block_early_mail_reply">smtp_tls_block_early_mail_reply</a>
+(default: no)</b></DT><DD>
+
+<p> Try to detect a mail hijacking attack based on a TLS protocol
+vulnerability (CVE-2009-3555), where an attacker prepends malicious
+HELO/MAIL/RCPT/DATA commands to a Postfix client TLS session. The
+attack would succeed with non-Postfix SMTP servers that reply to
+the malicious HELO/MAIL/RCPT/DATA commands after negotiating the
+Postfix SMTP client TLS session. </p>
+
+<p> This feature is available in Postfix 2.7. </p>
+
+
</DD>
<DT><b><a name="smtp_tls_cert_file">smtp_tls_cert_file</a>
File with the Postfix SMTP client ECDSA private key
in PEM format.
+ Available in Postfix version 2.7 and later:
+
+ <b><a href="postconf.5.html#smtp_tls_block_early_mail_reply">smtp_tls_block_early_mail_reply</a> (no)</b>
+ Try to detect a mail hijacking attack based on a
+ TLS protocol vulnerability (CVE-2009-3555), where
+ an attacker prepends malicious HELO/MAIL/RCPT/DATA
+ commands to a Postfix client TLS session.
+
<b>OBSOLETE STARTTLS CONTROLS</b>
- The following configuration parameters exist for compati-
+ The following configuration parameters exist for compati-
bility with Postfix versions before 2.3. Support for these
will be removed in a future release.
<b><a href="postconf.5.html#smtp_use_tls">smtp_use_tls</a> (no)</b>
- Opportunistic mode: use TLS when a remote SMTP
- server announces STARTTLS support, otherwise send
+ Opportunistic mode: use TLS when a remote SMTP
+ server announces STARTTLS support, otherwise send
the mail in the clear.
<b><a href="postconf.5.html#smtp_enforce_tls">smtp_enforce_tls</a> (no)</b>
- Enforcement mode: require that remote SMTP servers
- use TLS encryption, and never send mail in the
+ Enforcement mode: require that remote SMTP servers
+ use TLS encryption, and never send mail in the
clear.
<b><a href="postconf.5.html#smtp_tls_enforce_peername">smtp_tls_enforce_peername</a> (yes)</b>
- With mandatory TLS encryption, require that the
+ With mandatory TLS encryption, require that the
remote SMTP server hostname matches the information
in the remote SMTP server certificate.
<b><a href="postconf.5.html#smtp_tls_per_site">smtp_tls_per_site</a> (empty)</b>
Optional lookup tables with the Postfix SMTP client
- TLS usage policy by next-hop destination and by
+ TLS usage policy by next-hop destination and by
remote SMTP server hostname.
<b><a href="postconf.5.html#smtp_tls_cipherlist">smtp_tls_cipherlist</a> (empty)</b>
<b>RESOURCE AND RATE CONTROLS</b>
<b><a href="postconf.5.html#smtp_destination_concurrency_limit">smtp_destination_concurrency_limit</a> ($<a href="postconf.5.html#default_destination_concurrency_limit">default_destina</a>-</b>
<b><a href="postconf.5.html#default_destination_concurrency_limit">tion_concurrency_limit</a>)</b>
- The maximal number of parallel deliveries to the
- same destination via the smtp message delivery
+ The maximal number of parallel deliveries to the
+ same destination via the smtp message delivery
transport.
<b><a href="postconf.5.html#smtp_destination_recipient_limit">smtp_destination_recipient_limit</a> ($<a href="postconf.5.html#default_destination_recipient_limit">default_destina</a>-</b>
<b><a href="postconf.5.html#default_destination_recipient_limit">tion_recipient_limit</a>)</b>
- The maximal number of recipients per message for
+ The maximal number of recipients per message for
the smtp message delivery transport.
<b><a href="postconf.5.html#smtp_connect_timeout">smtp_connect_timeout</a> (30s)</b>
- The SMTP client time limit for completing a TCP
+ The SMTP client time limit for completing a TCP
connection, or zero (use the operating system
built-in time limit).
<b><a href="postconf.5.html#smtp_helo_timeout">smtp_helo_timeout</a> (300s)</b>
- The SMTP client time limit for sending the HELO or
- EHLO command, and for receiving the initial server
+ The SMTP client time limit for sending the HELO or
+ EHLO command, and for receiving the initial server
response.
<b><a href="postconf.5.html#lmtp_lhlo_timeout">lmtp_lhlo_timeout</a> (300s)</b>
- The LMTP client time limit for sending the LHLO
+ The LMTP client time limit for sending the LHLO
command, and for receiving the initial server
response.
command, and for receiving the server response.
<b><a href="postconf.5.html#smtp_mail_timeout">smtp_mail_timeout</a> (300s)</b>
- The SMTP client time limit for sending the MAIL
- FROM command, and for receiving the server
+ The SMTP client time limit for sending the MAIL
+ FROM command, and for receiving the server
response.
<b><a href="postconf.5.html#smtp_rcpt_timeout">smtp_rcpt_timeout</a> (300s)</b>
- The SMTP client time limit for sending the SMTP
- RCPT TO command, and for receiving the server
+ The SMTP client time limit for sending the SMTP
+ RCPT TO command, and for receiving the server
response.
<b><a href="postconf.5.html#smtp_data_init_timeout">smtp_data_init_timeout</a> (120s)</b>
- The SMTP client time limit for sending the SMTP
- DATA command, and for receiving the server
+ The SMTP client time limit for sending the SMTP
+ DATA command, and for receiving the server
response.
<b><a href="postconf.5.html#smtp_data_xfer_timeout">smtp_data_xfer_timeout</a> (180s)</b>
- The SMTP client time limit for sending the SMTP
+ The SMTP client time limit for sending the SMTP
message content.
<b><a href="postconf.5.html#smtp_data_done_timeout">smtp_data_done_timeout</a> (600s)</b>
- The SMTP client time limit for sending the SMTP
+ The SMTP client time limit for sending the SMTP
".", and for receiving the server response.
<b><a href="postconf.5.html#smtp_quit_timeout">smtp_quit_timeout</a> (300s)</b>
- The SMTP client time limit for sending the QUIT
+ The SMTP client time limit for sending the QUIT
command, and for receiving the server response.
Available in Postfix version 2.1 and later:
lookups, or zero (no limit).
<b><a href="postconf.5.html#smtp_mx_session_limit">smtp_mx_session_limit</a> (2)</b>
- The maximal number of SMTP sessions per delivery
- request before giving up or delivering to a fall-
+ The maximal number of SMTP sessions per delivery
+ request before giving up or delivering to a fall-
back <a href="postconf.5.html#relayhost">relay host</a>, or zero (no limit).
<b><a href="postconf.5.html#smtp_rset_timeout">smtp_rset_timeout</a> (20s)</b>
- The SMTP client time limit for sending the RSET
+ The SMTP client time limit for sending the RSET
command, and for receiving the server response.
Available in Postfix version 2.2 and earlier:
Available in Postfix version 2.2 and later:
<b><a href="postconf.5.html#smtp_connection_cache_destinations">smtp_connection_cache_destinations</a> (empty)</b>
- Permanently enable SMTP connection caching for the
+ Permanently enable SMTP connection caching for the
specified destinations.
<b><a href="postconf.5.html#smtp_connection_cache_on_demand">smtp_connection_cache_on_demand</a> (yes)</b>
- Temporarily enable SMTP connection caching while a
+ Temporarily enable SMTP connection caching while a
destination has a high volume of mail in the active
queue.
<b><a href="postconf.5.html#smtp_connection_cache_time_limit">smtp_connection_cache_time_limit</a> (2s)</b>
When SMTP connection caching is enabled, the amount
- of time that an unused SMTP client socket is kept
+ of time that an unused SMTP client socket is kept
open before it is closed.
Available in Postfix version 2.3 and later:
<b><a href="postconf.5.html#connection_cache_protocol_timeout">connection_cache_protocol_timeout</a> (5s)</b>
- Time limit for connection cache connect, send or
+ Time limit for connection cache connect, send or
receive operations.
<b>TROUBLE SHOOTING CONTROLS</b>
<b><a href="postconf.5.html#debug_peer_level">debug_peer_level</a> (2)</b>
- The increment in verbose logging level when a
- remote client or server matches a pattern in the
+ The increment in verbose logging level when a
+ remote client or server matches a pattern in the
<a href="postconf.5.html#debug_peer_list">debug_peer_list</a> parameter.
<b><a href="postconf.5.html#debug_peer_list">debug_peer_list</a> (empty)</b>
- Optional list of remote client or server hostname
- or network address patterns that cause the verbose
- logging level to increase by the amount specified
+ Optional list of remote client or server hostname
+ or network address patterns that cause the verbose
+ logging level to increase by the amount specified
in $<a href="postconf.5.html#debug_peer_level">debug_peer_level</a>.
<b><a href="postconf.5.html#error_notice_recipient">error_notice_recipient</a> (postmaster)</b>
- The recipient of postmaster notifications about
- mail delivery problems that are caused by policy,
+ The recipient of postmaster notifications about
+ mail delivery problems that are caused by policy,
resource, software or protocol errors.
<b><a href="postconf.5.html#internal_mail_filter_classes">internal_mail_filter_classes</a> (empty)</b>
- What categories of Postfix-generated mail are sub-
- ject to before-queue content inspection by
+ What categories of Postfix-generated mail are sub-
+ ject to before-queue content inspection by
<a href="postconf.5.html#non_smtpd_milters">non_smtpd_milters</a>, <a href="postconf.5.html#header_checks">header_checks</a> and <a href="postconf.5.html#body_checks">body_checks</a>.
<b><a href="postconf.5.html#notify_classes">notify_classes</a> (resource, software)</b>
- The list of error classes that are reported to the
+ The list of error classes that are reported to the
postmaster.
<b>MISCELLANEOUS CONTROLS</b>
<b><a href="postconf.5.html#best_mx_transport">best_mx_transport</a> (empty)</b>
- Where the Postfix SMTP client should deliver mail
+ Where the Postfix SMTP client should deliver mail
when it detects a "mail loops back to myself" error
condition.
<b><a href="postconf.5.html#config_directory">config_directory</a> (see 'postconf -d' output)</b>
- The default location of the Postfix <a href="postconf.5.html">main.cf</a> and
+ The default location of the Postfix <a href="postconf.5.html">main.cf</a> and
<a href="master.5.html">master.cf</a> configuration files.
<b><a href="postconf.5.html#daemon_timeout">daemon_timeout</a> (18000s)</b>
- How much time a Postfix daemon process may take to
- handle a request before it is terminated by a
+ How much time a Postfix daemon process may take to
+ handle a request before it is terminated by a
built-in watchdog timer.
<b><a href="postconf.5.html#delay_logging_resolution_limit">delay_logging_resolution_limit</a> (2)</b>
- The maximal number of digits after the decimal
+ The maximal number of digits after the decimal
point when logging sub-second delay values.
<b><a href="postconf.5.html#disable_dns_lookups">disable_dns_lookups</a> (no)</b>
- Disable DNS lookups in the Postfix SMTP and LMTP
+ Disable DNS lookups in the Postfix SMTP and LMTP
clients.
<b><a href="postconf.5.html#inet_interfaces">inet_interfaces</a> (all)</b>
tem receives mail on.
<b><a href="postconf.5.html#inet_protocols">inet_protocols</a> (ipv4)</b>
- The Internet protocols Postfix will attempt to use
+ The Internet protocols Postfix will attempt to use
when making or accepting connections.
<b><a href="postconf.5.html#ipc_timeout">ipc_timeout</a> (3600s)</b>
over an internal communication channel.
<b><a href="postconf.5.html#lmtp_assume_final">lmtp_assume_final</a> (no)</b>
- When an LMTP server announces no DSN support,
+ When an LMTP server announces no DSN support,
assume that the server performs final delivery, and
- send "delivered" delivery status notifications
+ send "delivered" delivery status notifications
instead of "relayed".
<b><a href="postconf.5.html#lmtp_tcp_port">lmtp_tcp_port</a> (24)</b>
- The default TCP port that the Postfix LMTP client
+ The default TCP port that the Postfix LMTP client
connects to.
<b><a href="postconf.5.html#max_idle">max_idle</a> (100s)</b>
- The maximum amount of time that an idle Postfix
- daemon process waits for an incoming connection
+ The maximum amount of time that an idle Postfix
+ daemon process waits for an incoming connection
before terminating voluntarily.
<b><a href="postconf.5.html#max_use">max_use</a> (100)</b>
- The maximal number of incoming connections that a
- Postfix daemon process will service before termi-
+ The maximal number of incoming connections that a
+ Postfix daemon process will service before termi-
nating voluntarily.
<b><a href="postconf.5.html#process_id">process_id</a> (read-only)</b>
- The process ID of a Postfix command or daemon
+ The process ID of a Postfix command or daemon
process.
<b><a href="postconf.5.html#process_name">process_name</a> (read-only)</b>
- The process name of a Postfix command or daemon
+ The process name of a Postfix command or daemon
process.
<b><a href="postconf.5.html#proxy_interfaces">proxy_interfaces</a> (empty)</b>
The network interface addresses that this mail sys-
- tem receives mail on by way of a proxy or network
+ tem receives mail on by way of a proxy or network
address translation unit.
<b><a href="postconf.5.html#smtp_bind_address">smtp_bind_address</a> (empty)</b>
- An optional numerical network address that the
- Postfix SMTP client should bind to when making an
+ An optional numerical network address that the
+ Postfix SMTP client should bind to when making an
IPv4 connection.
<b><a href="postconf.5.html#smtp_bind_address6">smtp_bind_address6</a> (empty)</b>
- An optional numerical network address that the
- Postfix SMTP client should bind to when making an
+ An optional numerical network address that the
+ Postfix SMTP client should bind to when making an
IPv6 connection.
<b><a href="postconf.5.html#smtp_helo_name">smtp_helo_name</a> ($<a href="postconf.5.html#myhostname">myhostname</a>)</b>
- The hostname to send in the SMTP EHLO or HELO com-
+ The hostname to send in the SMTP EHLO or HELO com-
mand.
<b><a href="postconf.5.html#lmtp_lhlo_name">lmtp_lhlo_name</a> ($<a href="postconf.5.html#myhostname">myhostname</a>)</b>
The hostname to send in the LMTP LHLO command.
<b><a href="postconf.5.html#smtp_host_lookup">smtp_host_lookup</a> (dns)</b>
- What mechanisms when the Postfix SMTP client uses
- to look up a host's IP address.
+ What mechanisms the Postfix SMTP client uses to
+ look up a host's IP address.
<b><a href="postconf.5.html#smtp_randomize_addresses">smtp_randomize_addresses</a> (yes)</b>
- Randomize the order of equal-preference MX host
+ Randomize the order of equal-preference MX host
addresses.
<b><a href="postconf.5.html#syslog_facility">syslog_facility</a> (mail)</b>
The syslog facility of Postfix logging.
<b><a href="postconf.5.html#syslog_name">syslog_name</a> (see 'postconf -d' output)</b>
- The mail system name that is prepended to the
- process name in syslog records, so that "smtpd"
+ The mail system name that is prepended to the
+ process name in syslog records, so that "smtpd"
becomes, for example, "postfix/smtpd".
Available with Postfix 2.2 and earlier:
<b><a href="postconf.5.html#fallback_relay">fallback_relay</a> (empty)</b>
- Optional list of relay hosts for SMTP destinations
+ Optional list of relay hosts for SMTP destinations
that can't be found or that are unreachable.
Available with Postfix 2.3 and later:
<b><a href="postconf.5.html#smtp_fallback_relay">smtp_fallback_relay</a> ($<a href="postconf.5.html#fallback_relay">fallback_relay</a>)</b>
- Optional list of relay hosts for SMTP destinations
+ Optional list of relay hosts for SMTP destinations
that can't be found or that are unreachable.
<b>SEE ALSO</b>
<a href="TLS_README.html">TLS_README</a>, Postfix STARTTLS howto
<b>LICENSE</b>
- The Secure Mailer license must be distributed with this
+ The Secure Mailer license must be distributed with this
software.
<b>AUTHOR(S)</b>
.ft R
.PP
This feature is available in Postfix 2.2 and later.
+.SH smtp_tls_block_early_mail_reply (default: no)
+Try to detect a mail hijacking attack based on a TLS protocol
+vulnerability (CVE-2009-3555), where an attacker prepends malicious
+HELO/MAIL/RCPT/DATA commands to a Postfix client TLS session. The
+attack would succeed with non-Postfix SMTP servers that reply to
+the malicious HELO/MAIL/RCPT/DATA commands after negotiating the
+Postfix SMTP client TLS session.
+.PP
+This feature is available in Postfix 2.7.
.SH smtp_tls_cert_file (default: empty)
File with the Postfix SMTP client RSA certificate in PEM format.
This file may also contain the Postfix SMTP client private RSA key,
File with the Postfix SMTP client ECDSA certificate in PEM format.
.IP "\fBsmtp_tls_eckey_file ($smtp_tls_eccert_file)\fR"
File with the Postfix SMTP client ECDSA private key in PEM format.
+.PP
+Available in Postfix version 2.7 and later:
+.IP "\fBsmtp_tls_block_early_mail_reply (no)\fR"
+Try to detect a mail hijacking attack based on a TLS protocol
+vulnerability (CVE-2009-3555), where an attacker prepends malicious
+HELO/MAIL/RCPT/DATA commands to a Postfix client TLS session.
.SH "OBSOLETE STARTTLS CONTROLS"
.na
.nf
.IP "\fBlmtp_lhlo_name ($myhostname)\fR"
The hostname to send in the LMTP LHLO command.
.IP "\fBsmtp_host_lookup (dns)\fR"
-What mechanisms when the Postfix SMTP client uses to look up a host's IP
+What mechanisms the Postfix SMTP client uses to look up a host's IP
address.
.IP "\fBsmtp_randomize_addresses (yes)\fR"
Randomize the order of equal-preference MX host addresses.
s;\blmtp_enforce_tls\b;<a href="postconf.5.html#lmtp_enforce_tls">$&</a>;g;
s;\blmtp_tls_enforce_peername\b;<a href="postconf.5.html#lmtp_tls_enforce_peername">$&</a>;g;
s;\blmtp_tls_note_starttls_offer\b;<a href="postconf.5.html#lmtp_tls_note_starttls_offer">$&</a>;g;
+ s;\blmtp_tls_block_early_mail_reply\b;<a href="postconf.5.html#lmtp_tls_block_early_mail_reply">$&</a>;g;
s;\blmtp_sender_dependent_authentication\b;<a href="postconf.5.html#lmtp_sender_dependent_authentication">$&</a>;g;
s;\blmtp_sasl_path\b;<a href="postconf.5.html#lmtp_sasl_path">$&</a>;g;
s;\blmtp_lhlo_name\b;<a href="postconf.5.html#lmtp_lhlo_name">$&</a>;g;
s;\bsmtp_tls_security_level\b;<a href="postconf.5.html#smtp_tls_security_level">$&</a>;g;
s;\bsmtp_tls_session_cache_database\b;<a href="postconf.5.html#smtp_tls_session_cache_database">$&</a>;g;
s;\bsmtp_tls_session_cache_timeout\b;<a href="postconf.5.html#smtp_tls_session_cache_timeout">$&</a>;g;
+ s;\bsmtp_tls_block_early_mail_reply\b;<a href="postconf.5.html#smtp_tls_block_early_mail_reply">$&</a>;g;
s;\bsmtp_use_tls\b;<a href="postconf.5.html#smtp_use_tls">$&</a>;g;
s;\bsmtp_header_checks\b;<a href="postconf.5.html#smtp_header_checks">$&</a>;g;
s;\bsmtp_mime_header_checks\b;<a href="postconf.5.html#smtp_mime_header_checks">$&</a>;g;
</pre>
<p> This feature is available in Postfix 2.7. </p>
+
+%PARAM smtp_tls_block_early_mail_reply no
+
+<p> Try to detect a mail hijacking attack based on a TLS protocol
+vulnerability (CVE-2009-3555), where an attacker prepends malicious
+HELO/MAIL/RCPT/DATA commands to a Postfix client TLS session. The
+attack would succeed with non-Postfix SMTP servers that reply to
+the malicious HELO/MAIL/RCPT/DATA commands after negotiating the
+Postfix SMTP client TLS session. </p>
+
+<p> This feature is available in Postfix 2.7. </p>
#define DEF_LMTP_TLS_FPT_CMATCH ""
extern char *var_smtp_tls_fpt_cmatch;
+#define VAR_SMTP_TLS_BLK_EARLY_MAIL_REPLY "smtp_tls_block_early_mail_reply"
+#define DEF_SMTP_TLS_BLK_EARLY_MAIL_REPLY 0
+#define VAR_LMTP_TLS_BLK_EARLY_MAIL_REPLY "lmtp_tls_block_early_mail_reply"
+#define DEF_LMTP_TLS_BLK_EARLY_MAIL_REPLY 0
+extern bool var_smtp_tls_blk_early_mail_reply;
+
/*
* SASL authentication support, SMTP server side.
*/
* Patches change both the patchlevel and the release date. Snapshots have no
* patchlevel; they change the release date only.
*/
-#define MAIL_RELEASE_DATE "20091109"
+#define MAIL_RELEASE_DATE "20091110"
#define MAIL_VERSION_NUMBER "2.7"
#ifdef SNAPSHOT
#ifdef USE_TLS
VAR_LMTP_TLS_ENFORCE_PN, DEF_LMTP_TLS_ENFORCE_PN, &var_smtp_tls_enforce_peername,
VAR_LMTP_TLS_NOTEOFFER, DEF_LMTP_TLS_NOTEOFFER, &var_smtp_tls_note_starttls_offer,
+ VAR_LMTP_TLS_BLK_EARLY_MAIL_REPLY, DEF_LMTP_TLS_BLK_EARLY_MAIL_REPLY, &var_smtp_tls_blk_early_mail_reply,
#endif
VAR_LMTP_SENDER_AUTH, DEF_LMTP_SENDER_AUTH, &var_smtp_sender_auth,
VAR_LMTP_CNAME_OVERR, DEF_LMTP_CNAME_OVERR, &var_smtp_cname_overr,
/* File with the Postfix SMTP client ECDSA certificate in PEM format.
/* .IP "\fBsmtp_tls_eckey_file ($smtp_tls_eccert_file)\fR"
/* File with the Postfix SMTP client ECDSA private key in PEM format.
+/* .PP
+/* Available in Postfix version 2.7 and later:
+/* .IP "\fBsmtp_tls_block_early_mail_reply (no)\fR"
+/* Try to detect a mail hijacking attack based on a TLS protocol
+/* vulnerability (CVE-2009-3555), where an attacker prepends malicious
+/* HELO/MAIL/RCPT/DATA commands to a Postfix client TLS session.
/* OBSOLETE STARTTLS CONTROLS
/* .ad
/* .fi
/* .IP "\fBlmtp_lhlo_name ($myhostname)\fR"
/* The hostname to send in the LMTP LHLO command.
/* .IP "\fBsmtp_host_lookup (dns)\fR"
-/* What mechanisms when the Postfix SMTP client uses to look up a host's IP
+/* What mechanisms the Postfix SMTP client uses to look up a host's IP
/* address.
/* .IP "\fBsmtp_randomize_addresses (yes)\fR"
/* Randomize the order of equal-preference MX host addresses.
char *var_smtp_tls_ciph;
char *var_smtp_tls_eccert_file;
char *var_smtp_tls_eckey_file;
+bool var_smtp_tls_blk_early_mail_reply;
#endif
#define SMTP_FEATURE_PIX_NO_ESMTP (1<<16) /* PIX smtp fixup mode */
#define SMTP_FEATURE_PIX_DELAY_DOTCRLF (1<<17) /* PIX smtp fixup mode */
#define SMTP_FEATURE_XFORWARD_PORT (1<<18)
+#define SMTP_FEATURE_EARLY_TLS_MAIL_REPLY (1<<19) /* CVE-2009-3555 */
/*
* Features that passivate under the endpoint.
#ifdef USE_TLS
VAR_SMTP_TLS_ENFORCE_PN, DEF_SMTP_TLS_ENFORCE_PN, &var_smtp_tls_enforce_peername,
VAR_SMTP_TLS_NOTEOFFER, DEF_SMTP_TLS_NOTEOFFER, &var_smtp_tls_note_starttls_offer,
+ VAR_SMTP_TLS_BLK_EARLY_MAIL_REPLY, DEF_SMTP_TLS_BLK_EARLY_MAIL_REPLY, &var_smtp_tls_blk_early_mail_reply,
#endif
VAR_SMTP_SENDER_AUTH, DEF_SMTP_SENDER_AUTH, &var_smtp_sender_auth,
VAR_SMTP_CNAME_OVERR, DEF_SMTP_CNAME_OVERR, &var_smtp_cname_overr,
&& (session->features & SMTP_FEATURE_AUTH))
vstring_strcat(next_command, " AUTH=<>");
#endif
+
+ /*
+ * CVE-2009-3555 (TLS renegotiation). Try to detect a mail
+ * hijacking attack that prepends malicious EHLO/MAIL/RCPT/DATA
+ * commands to our TLS session.
+ *
+ * For the attack to succeed, the remote SMTP server must reply to
+ * the malicious EHLO/MAIL/RCPT/DATA commands after completing
+ * TLS (re)negotiation, so that the replies arrive in our TLS
+ * session (otherwise the Postfix SMTP client would time out
+ * waiting for an answer). With some luck we can detect this
+ * specific attack as a server MAIL reply that arrives before we
+ * send our own MAIL command.
+ *
+ * We don't apply this test to the HELO command because the result
+ * would be very timing sensitive, and we don't apply this test
+ * to RCPT and DATA replies because these may be pipelined for
+ * legitimate reasons.
+ */
+#ifdef USE_TLS
+ if (var_smtp_tls_blk_early_mail_reply
+ && (state->misc_flags & SMTP_MISC_FLAG_IN_STARTTLS) != 0
+ && (vstream_peek(session->stream) > 0
+ || peekfd(vstream_fileno(session->stream)) > 0))
+ session->features |= SMTP_FEATURE_EARLY_TLS_MAIL_REPLY;
+#endif
+
+ /*
+ * We now return to our regular broadcast.
+ */
next_state = SMTP_STATE_RCPT;
break;
xfer_request[SMTP_STATE_MAIL]);
mail_from_rejected = 1;
}
+
+ /*
+ * CVE-2009-3555 (TLS renegotiation). Whatever it was
+ * that arrived before we sent our MAIL FROM command, it
+ * was not a fatal-level TLS alert message. It could be a
+ * warning-level TLS alert message, or a ChangeCipherSpec
+ * message, but such messages are not normally sent in
+ * the middle of a TLS session. We disconnect and try
+ * again later.
+ */
+#ifdef USE_TLS
+ if (var_smtp_tls_blk_early_mail_reply
+ && (session->features & SMTP_FEATURE_EARLY_TLS_MAIL_REPLY)) {
+ smtp_site_fail(state, DSN_BY_LOCAL_MTA,
+ SMTP_RESP_FAKE(&fake, "4.7.0"),
+ "unexpected server message");
+ msg_warn("server %s violates %s policy",
+ session->namaddr,
+ VAR_SMTP_TLS_BLK_EARLY_MAIL_REPLY);
+ mail_from_rejected = 1;
+ }
+#endif
+
+ /*
+ * We now return to our regular broadcast.
+ */
recv_state = SMTP_STATE_RCPT;
break;
for (ifa = ifap; ifa; ifa = ifa->ifa_next) {
if (!(ifa->ifa_flags & IFF_UP) || ifa->ifa_addr == 0)
continue;
+ /* XXX Should we cons up a default mask instead? */
+ if (ifa->ifa_netmask == 0)
+ continue;
sa = ifa->ifa_addr;
sam = ifa->ifa_netmask;
if (af != AF_UNSPEC && sa->sa_family != af)
projects / thirdparty / postfix.git / commitdiff
