postfix-2.8-20110103

diff --git a/postfix/HISTORY b/postfix/HISTORY
index 19eef1a2e4774b0d23cc61898684560edd2c8374..50274e0f3ab392e78e034ed1ff936736c9ef48a1 100644 (file)
--- a/postfix/HISTORY
+++ b/postfix/HISTORY
@@ -16337,5 +16337,15 @@ Apologies for any names omitted.
        TLS <=> plaintext for postscreen(8). One tlsproxy(8) process
        can translate traffic for multiple remote SMTP clients.
        With early testing feedback from Victor Duchovni and Christian
-       Roessner.  Files: util/nbbio.c, tlsproxy/starttlsd.c,
-       tlsproxy/starttlsd_state.c.
+       Roessner.  Files: util/nbbio.[hc], tlsproxy/*.[hc],
+       postscreen/postscreen_starttlsd.c, postscreen/postscreen_smtpd.c.
+
+20101103
+
+       Cleanup: missing tls_level support in tlsproxy (it has no
+       way to send plaintext, but perhaps an informative error
+       message is in order anyway).  File: tlsproxy/tlsproxy.c.
+
+       Cleanup: simplified the handling of throttled output (i.e.
+       output that can't be sent because the receiver tries to be
+       nasty).  File: postscreen/postscreen_send.c.

diff --git a/postfix/WISHLIST b/postfix/WISHLIST
index 3092ca6fce9d4586957a2e6df0cf504b32e40322..016482248bd6db892a749dad7e5f1ec6e7761939 100644 (file)
--- a/postfix/WISHLIST
+++ b/postfix/WISHLIST
@@ -4,7 +4,12 @@ Wish list:
 
        anvil rate limit for sasl_username.
 
-       encapsulate nbbio buffer access and update by tlsproxy.
+       Encapsulate nbbio buffer access and update by tlsproxy.
+
+       Full-duplex support for tlsproxy(8). This requires updating
+       events(3) and nbbio(3).
+
+       Register automagic destructor for object attached to VSTREAM.
 
        smtpd xclient option for sasl_username.
 

diff --git a/postfix/html/postscreen.8.html b/postfix/html/postscreen.8.html
index a4ab206fcb15b9598a53b2273e559e79bc533cff..4f7250d7e2a2e5412f53308706e7367afa9aa03b 100644 (file)
--- a/postfix/html/postscreen.8.html
+++ b/postfix/html/postscreen.8.html
@@ -60,98 +60,101 @@ POSTSCREEN(8)                                                    POSTSCREEN(8)
        <a href="http://tools.ietf.org/html/rfc3207">RFC 3207</a> (STARTTLS command)
        <a href="http://tools.ietf.org/html/rfc3461">RFC 3461</a> (SMTP DSN Extension)
        <a href="http://tools.ietf.org/html/rfc3463">RFC 3463</a> (Enhanced Status Codes)
-       <a href="http://tools.ietf.org/html/rfc5321">RFC 5321</a> (SMTP protocol, including multi-line 220 greetings)
+       <a href="http://tools.ietf.org/html/rfc5321">RFC 5321</a> (SMTP protocol, including multi-line 220 banners)
 
 <b>DIAGNOSTICS</b>
        Problems and transactions are logged to <b>syslogd</b>(8).
 
 <b>BUGS</b>
-       The <a href="postscreen.8.html"><b>postscreen</b>(8)</a> built-in SMTP protocol engine  currently
-       does  not  announce support for AUTH, XCLIENT or XFORWARD.
-       Support for AUTH may be added in the future.  In the  mean
+       The  <a href="postscreen.8.html"><b>postscreen</b>(8)</a>  server  does  not  yet  implement  the
+       <b><a href="postconf.5.html#soft_bounce">soft_bounce</a></b> feature.
+
+       The  <a href="postscreen.8.html"><b>postscreen</b>(8)</a> built-in SMTP protocol engine currently
+       does not announce support for AUTH, XCLIENT  or  XFORWARD.
+       Support  for AUTH may be added in the future.  In the mean
        time, if you need to make these services available on port
-       25, then do not enable  the  optional  "after  220  server
+       25,  then  do  not  enable  the optional "after 220 server
        greeting" tests.
 
-       The  optional  "after  220  server greeting" tests involve
-       <a href="postscreen.8.html"><b>postscreen</b>(8)</a>'s built-in SMTP protocol engine. When  these
+       The optional "after 220  server  greeting"  tests  involve
+       <a href="postscreen.8.html"><b>postscreen</b>(8)</a>'s  built-in SMTP protocol engine. When these
        tests succeed, <a href="postscreen.8.html"><b>postscreen</b>(8)</a> adds the client to the tempo-
-       rary whitelist but it cannot not hand off the "live"  con-
-       nection  to a Postfix SMTP server process in the middle of
-       a session.   Instead,  <a href="postscreen.8.html"><b>postscreen</b>(8)</a>  defers  attempts  to
-       deliver  mail  with a 4XX status, and waits for the client
-       to disconnect.  The next time a good client  connects,  it
-       will  be  allowed to talk to a Postfix SMTP server process
-       to deliver mail. <a href="postscreen.8.html"><b>postscreen</b>(8)</a>  mitigates  the  impact  of
-       this  limitation  by  giving  such tests a long expiration
+       rary  whitelist but it cannot not hand off the "live" con-
+       nection to a Postfix SMTP server process in the middle  of
+       a  session.   Instead,  <a href="postscreen.8.html"><b>postscreen</b>(8)</a>  defers  attempts to
+       deliver mail with a 4XX status, and waits for  the  client
+       to  disconnect.   The next time a good client connects, it
+       will be allowed to talk to a Postfix SMTP  server  process
+       to  deliver  mail.  <a href="postscreen.8.html"><b>postscreen</b>(8)</a>  mitigates the impact of
+       this limitation by giving such  tests  a  long  expiration
        time.
 
 <b>CONFIGURATION PARAMETERS</b>
-       Changes to <a href="postconf.5.html">main.cf</a> are not  picked  up  automatically,  as
-       <a href="postscreen.8.html"><b>postscreen</b>(8)</a>  processes  may  run for several hours.  Use
+       Changes  to  <a href="postconf.5.html">main.cf</a>  are  not picked up automatically, as
+       <a href="postscreen.8.html"><b>postscreen</b>(8)</a> processes may run for  several  hours.   Use
        the command "postfix reload" after a configuration change.
 
-       The  text  below  provides  only  a parameter summary. See
+       The text below provides  only  a  parameter  summary.  See
        <a href="postconf.5.html"><b>postconf</b>(5)</a> for more details including examples.
 
        NOTE:  Some  <a href="postscreen.8.html"><b>postscreen</b>(8)</a>  parameters  implement  stress-
-       dependent  behavior.   This  is  supported  only  when the
-       default parameter value is stress-dependent (that  is,  it
-       looks  like  ${stress?X}${stress:Y}, or it is the $<i>name</i> of
+       dependent behavior.   This  is  supported  only  when  the
+       default  parameter  value is stress-dependent (that is, it
+       looks like ${stress?X}${stress:Y}, or it is the  $<i>name</i>  of
        an  smtpd  parameter  with  a  stress-dependent  default).
-       Other  parameters always evaluate as if the <b>stress</b> parame-
+       Other parameters always evaluate as if the <b>stress</b>  parame-
        ter value is the empty string.
 
 <b>COMPATIBILITY CONTROLS</b>
        <b><a href="postconf.5.html#postscreen_discard_ehlo_keyword_address_maps">postscreen_discard_ehlo_keyword_address_maps</a>  ($<a href="postconf.5.html#smtpd_discard_ehlo_keyword_address_maps">smtpd_dis</a>-</b>
        <b><a href="postconf.5.html#smtpd_discard_ehlo_keyword_address_maps">card_ehlo_keyword_address_maps</a>)</b>
-              Lookup tables, indexed by the  remote  SMTP  client
-              address,  with  case insensitive lists of EHLO key-
-              words (pipelining, starttls, auth, etc.)  that  the
-              <a href="postscreen.8.html"><b>postscreen</b>(8)</a>  server  will  not  send  in the EHLO
+              Lookup  tables,  indexed  by the remote SMTP client
+              address, with case insensitive lists of  EHLO  key-
+              words  (pipelining,  starttls, auth, etc.) that the
+              <a href="postscreen.8.html"><b>postscreen</b>(8)</a> server will  not  send  in  the  EHLO
               response to a remote SMTP client.
 
        <b><a href="postconf.5.html#postscreen_discard_ehlo_keywords">postscreen_discard_ehlo_keywords</a> ($<a href="postconf.5.html#smtpd_discard_ehlo_keywords">smtpd_discard_ehlo_key</a>-</b>
        <b><a href="postconf.5.html#smtpd_discard_ehlo_keywords">words</a>)</b>
-              A case insensitive list of EHLO keywords  (pipelin-
-              ing,  starttls,  auth, etc.) that the <a href="postscreen.8.html"><b>postscreen</b>(8)</a>
-              server will not send in  the  EHLO  response  to  a
+              A  case insensitive list of EHLO keywords (pipelin-
+              ing, starttls, auth, etc.) that  the  <a href="postscreen.8.html"><b>postscreen</b>(8)</a>
+              server  will  not  send  in  the EHLO response to a
               remote SMTP client.
 
 <b>TRIAGE PARAMETERS</b>
        <b><a href="postconf.5.html#postscreen_bare_newline_action">postscreen_bare_newline_action</a> (ignore)</b>
-              The  action  that  <a href="postscreen.8.html"><b>postscreen</b>(8)</a> takes when an SMTP
-              client sends a bare newline character, that  is,  a
+              The action that <a href="postscreen.8.html"><b>postscreen</b>(8)</a> takes  when  an  SMTP
+              client  sends  a bare newline character, that is, a
               newline not preceded by carriage return.
 
        <b><a href="postconf.5.html#postscreen_bare_newline_enable">postscreen_bare_newline_enable</a> (no)</b>
-              Enable  "bare  newline"  SMTP protocol tests in the
+              Enable "bare newline" SMTP protocol  tests  in  the
               <a href="postscreen.8.html"><b>postscreen</b>(8)</a> server.
 
        <b><a href="postconf.5.html#postscreen_blacklist_action">postscreen_blacklist_action</a> (ignore)</b>
-              The action that <a href="postscreen.8.html"><b>postscreen</b>(8)</a> takes  when  an  SMTP
-              client   is   permanently   blacklisted   with  the
+              The  action  that  <a href="postscreen.8.html"><b>postscreen</b>(8)</a> takes when an SMTP
+              client  is   permanently   blacklisted   with   the
               <a href="postconf.5.html#postscreen_blacklist_networks">postscreen_blacklist_networks</a> parameter.
 
        <b><a href="postconf.5.html#postscreen_blacklist_networks">postscreen_blacklist_networks</a> (empty)</b>
               Network addresses that are permanently blacklisted;
-              see  the  <a href="postconf.5.html#postscreen_blacklist_action">postscreen_blacklist_action</a> parameter for
+              see the <a href="postconf.5.html#postscreen_blacklist_action">postscreen_blacklist_action</a>  parameter  for
               possible actions.
 
        <b><a href="postconf.5.html#postscreen_disable_vrfy_command">postscreen_disable_vrfy_command</a> ($<a href="postconf.5.html#disable_vrfy_command">disable_vrfy_command</a>)</b>
-              Disable the SMTP VRFY command in the  <a href="postscreen.8.html"><b>postscreen</b>(8)</a>
+              Disable  the SMTP VRFY command in the <a href="postscreen.8.html"><b>postscreen</b>(8)</a>
               daemon.
 
        <b><a href="postconf.5.html#postscreen_dnsbl_action">postscreen_dnsbl_action</a> (ignore)</b>
-              The  action  that  <a href="postscreen.8.html"><b>postscreen</b>(8)</a> takes when an SMTP
+              The action that <a href="postscreen.8.html"><b>postscreen</b>(8)</a> takes  when  an  SMTP
               client's  combined  DNSBL  score  is  equal  to  or
-              greater  than  a  threshold  (as  defined  with the
+              greater than  a  threshold  (as  defined  with  the
               <a href="postconf.5.html#postscreen_dnsbl_sites">postscreen_dnsbl_sites</a> and <a href="postconf.5.html#postscreen_dnsbl_threshold">postscreen_dnsbl_thresh</a>-
               <a href="postconf.5.html#postscreen_dnsbl_threshold">old</a> parameters).
 
        <b><a href="postconf.5.html#postscreen_dnsbl_reply_map">postscreen_dnsbl_reply_map</a> (empty)</b>
-              A  mapping  from  actual  DNSBL  domain  name which
-              includes a secret password,  to  the  DNSBL  domain
+              A mapping  from  actual  DNSBL  domain  name  which
+              includes  a  secret  password,  to the DNSBL domain
               name  that  postscreen  will  reply  with  when  it
               rejects mail.
 
@@ -160,16 +163,16 @@ POSTSCREEN(8)                                                    POSTSCREEN(8)
               weight factors.
 
        <b><a href="postconf.5.html#postscreen_dnsbl_threshold">postscreen_dnsbl_threshold</a> (1)</b>
-              The  inclusive  lower  bound  for  blocking an SMTP
+              The inclusive lower  bound  for  blocking  an  SMTP
               client,  based  on  its  combined  DNSBL  score  as
-              defined  with the <a href="postconf.5.html#postscreen_dnsbl_sites">postscreen_dnsbl_sites</a> parameter.
+              defined with the <a href="postconf.5.html#postscreen_dnsbl_sites">postscreen_dnsbl_sites</a>  parameter.
 
        <b><a href="postconf.5.html#postscreen_forbidden_commands">postscreen_forbidden_commands</a> ($<a href="postconf.5.html#smtpd_forbidden_commands">smtpd_forbidden_commands</a>)</b>
               List of commands that the <a href="postscreen.8.html"><b>postscreen</b>(8)</a> server con-
               siders in violation of the SMTP protocol.
 
        <b><a href="postconf.5.html#postscreen_greet_action">postscreen_greet_action</a> (ignore)</b>
-              The  action  that  <a href="postscreen.8.html"><b>postscreen</b>(8)</a> takes when an SMTP
+              The action that <a href="postscreen.8.html"><b>postscreen</b>(8)</a> takes  when  an  SMTP
               client speaks before its turn within the time spec-
               ified with the <a href="postconf.5.html#postscreen_greet_wait">postscreen_greet_wait</a> parameter.
 
@@ -177,151 +180,151 @@ POSTSCREEN(8)                                                    POSTSCREEN(8)
               The  <i>text</i>  in  the  optional  "220-<i>text</i>..."  server
               response that <a href="postscreen.8.html"><b>postscreen</b>(8)</a> sends ahead of the real
               Postfix SMTP server's "220 text..." response, in an
-              attempt to confuse bad SMTP clients  so  that  they
+              attempt  to  confuse  bad SMTP clients so that they
               speak before their turn (pre-greet).
 
        <b><a href="postconf.5.html#postscreen_greet_wait">postscreen_greet_wait</a> (${stress?2}${stress:6}s)</b>
               The amount of time that <a href="postscreen.8.html"><b>postscreen</b>(8)</a> will wait for
-              an SMTP client to send a command before  its  turn,
-              and  for  DNS  blocklist  lookup  results to arrive
-              (default: up to 2 seconds under  stress,  up  to  6
+              an  SMTP  client to send a command before its turn,
+              and for DNS  blocklist  lookup  results  to  arrive
+              (default:  up  to  2  seconds under stress, up to 6
               seconds otherwise).
 
        <b><a href="postconf.5.html#postscreen_helo_required">postscreen_helo_required</a> ($<a href="postconf.5.html#smtpd_helo_required">smtpd_helo_required</a>)</b>
-              Require  that  a  remote  SMTP client sends HELO or
+              Require that a remote SMTP  client  sends  HELO  or
               EHLO before commencing a MAIL transaction.
 
        <b><a href="postconf.5.html#postscreen_non_smtp_command_action">postscreen_non_smtp_command_action</a> (drop)</b>
-              The action that <a href="postscreen.8.html"><b>postscreen</b>(8)</a> takes  when  an  SMTP
-              client  sends  non-SMTP  commands as specified with
+              The  action  that  <a href="postscreen.8.html"><b>postscreen</b>(8)</a> takes when an SMTP
+              client sends non-SMTP commands  as  specified  with
               the <a href="postconf.5.html#postscreen_forbidden_commands">postscreen_forbidden_commands</a> parameter.
 
        <b><a href="postconf.5.html#postscreen_non_smtp_command_enable">postscreen_non_smtp_command_enable</a> (no)</b>
-              Enable   "non-SMTP   command"    tests    in    the
+              Enable    "non-SMTP    command"    tests   in   the
               <a href="postscreen.8.html"><b>postscreen</b>(8)</a> server.
 
        <b><a href="postconf.5.html#postscreen_pipelining_action">postscreen_pipelining_action</a> (enforce)</b>
-              The  action  that  <a href="postscreen.8.html"><b>postscreen</b>(8)</a> takes when an SMTP
-              client sends multiple commands instead  of  sending
-              one  command and waiting for the server to respond.
+              The action that <a href="postscreen.8.html"><b>postscreen</b>(8)</a> takes  when  an  SMTP
+              client  sends  multiple commands instead of sending
+              one command and waiting for the server to  respond.
 
        <b><a href="postconf.5.html#postscreen_pipelining_enable">postscreen_pipelining_enable</a> (no)</b>
-              Enable "pipelining"  SMTP  protocol  tests  in  the
+              Enable  "pipelining"  SMTP  protocol  tests  in the
               <a href="postscreen.8.html"><b>postscreen</b>(8)</a> server.
 
        <b><a href="postconf.5.html#postscreen_whitelist_networks">postscreen_whitelist_networks</a> ($<a href="postconf.5.html#mynetworks">mynetworks</a>)</b>
               Network addresses that are permanently whitelisted,
-              and that will not  be  subjected  to  <a href="postscreen.8.html"><b>postscreen</b>(8)</a>
+              and  that  will  not  be subjected to <a href="postscreen.8.html"><b>postscreen</b>(8)</a>
               checks.
 
        <b><a href="postconf.5.html#smtpd_service_name">smtpd_service_name</a> (smtpd)</b>
-              The  internal  service  that <a href="postscreen.8.html"><b>postscreen</b>(8)</a> forwards
+              The internal service  that  <a href="postscreen.8.html"><b>postscreen</b>(8)</a>  forwards
               allowed connections to.
 
 <b>CACHE CONTROLS</b>
        <b><a href="postconf.5.html#postscreen_cache_cleanup_interval">postscreen_cache_cleanup_interval</a> (12h)</b>
-              The amount  of  time  between  <a href="postscreen.8.html"><b>postscreen</b>(8)</a>  cache
+              The  amount  of  time  between  <a href="postscreen.8.html"><b>postscreen</b>(8)</a> cache
               cleanup runs.
 
        <b><a href="postconf.5.html#postscreen_cache_map">postscreen_cache_map</a> (btree:$<a href="postconf.5.html#data_directory">data_directory</a>/ps_cache)</b>
-              Persistent  storage  for  the  <a href="postscreen.8.html"><b>postscreen</b>(8)</a> server
+              Persistent storage  for  the  <a href="postscreen.8.html"><b>postscreen</b>(8)</a>  server
               decisions.
 
        <b><a href="postconf.5.html#postscreen_cache_retention_time">postscreen_cache_retention_time</a> (7d)</b>
               The amount of time that <a href="postscreen.8.html"><b>postscreen</b>(8)</a> will cache an
-              expired  temporary  whitelist  entry  before  it is
+              expired temporary  whitelist  entry  before  it  is
               removed.
 
        <b><a href="postconf.5.html#postscreen_bare_newline_ttl">postscreen_bare_newline_ttl</a> (30d)</b>
-              The amount of time that  <a href="postscreen.8.html"><b>postscreen</b>(8)</a>  will  cache
-              results  from a successful "bare newline" SMTP pro-
+              The  amount  of  time that <a href="postscreen.8.html"><b>postscreen</b>(8)</a> will cache
+              results from a successful "bare newline" SMTP  pro-
               tocol test.
 
        <b><a href="postconf.5.html#postscreen_dnsbl_ttl">postscreen_dnsbl_ttl</a> (1h)</b>
-              The amount of time that  <a href="postscreen.8.html"><b>postscreen</b>(8)</a>  will  cache
+              The  amount  of  time that <a href="postscreen.8.html"><b>postscreen</b>(8)</a> will cache
               results from a successful DNS blocklist test.
 
        <b><a href="postconf.5.html#postscreen_greet_ttl">postscreen_greet_ttl</a> (1d)</b>
-              The  amount  of  time that <a href="postscreen.8.html"><b>postscreen</b>(8)</a> will cache
+              The amount of time that  <a href="postscreen.8.html"><b>postscreen</b>(8)</a>  will  cache
               results from a successful PREGREET test.
 
        <b><a href="postconf.5.html#postscreen_non_smtp_command_ttl">postscreen_non_smtp_command_ttl</a> (30d)</b>
-              The amount of time that  <a href="postscreen.8.html"><b>postscreen</b>(8)</a>  will  cache
-              results  from  a successful "non_smtp_command" SMTP
+              The  amount  of  time that <a href="postscreen.8.html"><b>postscreen</b>(8)</a> will cache
+              results from a successful  "non_smtp_command"  SMTP
               protocol test.
 
        <b><a href="postconf.5.html#postscreen_pipelining_ttl">postscreen_pipelining_ttl</a> (30d)</b>
-              The amount of time that  <a href="postscreen.8.html"><b>postscreen</b>(8)</a>  will  cache
-              results  from a successful "pipelining" SMTP proto-
+              The  amount  of  time that <a href="postscreen.8.html"><b>postscreen</b>(8)</a> will cache
+              results from a successful "pipelining" SMTP  proto-
               col test.
 
 <b>RESOURCE CONTROLS</b>
        <b><a href="postconf.5.html#line_length_limit">line_length_limit</a> (2048)</b>
-              Upon input, long lines are chopped up  into  pieces
-              of  at  most this length; upon delivery, long lines
+              Upon  input,  long lines are chopped up into pieces
+              of at most this length; upon delivery,  long  lines
               are reconstructed.
 
        <b><a href="postconf.5.html#postscreen_client_connection_count_limit">postscreen_client_connection_count_limit</a></b>
        <b>($<a href="postconf.5.html#smtpd_client_connection_count_limit">smtpd_client_connection_count_limit</a>)</b>
-              How many simultaneous  connections  any  client  is
+              How  many  simultaneous  connections  any client is
               allowed to have with the <a href="postscreen.8.html"><b>postscreen</b>(8)</a> daemon.
 
        <b><a href="postconf.5.html#postscreen_command_count_limit">postscreen_command_count_limit</a> (20)</b>
-              The  limit on the total number of commands per SMTP
-              session for <a href="postscreen.8.html"><b>postscreen</b>(8)</a>'s built-in SMTP  protocol
+              The limit on the total number of commands per  SMTP
+              session  for <a href="postscreen.8.html"><b>postscreen</b>(8)</a>'s built-in SMTP protocol
               engine.
 
        <b><a href="postconf.5.html#postscreen_command_time_limit">postscreen_command_time_limit</a> (${stress?10}${stress:300}s)</b>
-              The  command  "read" time limit for <a href="postscreen.8.html"><b>postscreen</b>(8)</a>'s
+              The command "read" time limit  for  <a href="postscreen.8.html"><b>postscreen</b>(8)</a>'s
               built-in SMTP protocol engine.
 
        <b><a href="postconf.5.html#postscreen_post_queue_limit">postscreen_post_queue_limit</a> ($<a href="postconf.5.html#default_process_limit">default_process_limit</a>)</b>
-              The number of clients that can be waiting for  ser-
+              The  number of clients that can be waiting for ser-
               vice from a real SMTP server process.
 
        <b><a href="postconf.5.html#postscreen_pre_queue_limit">postscreen_pre_queue_limit</a> ($<a href="postconf.5.html#default_process_limit">default_process_limit</a>)</b>
-              The  number  of non-whitelisted clients that can be
-              waiting for a decision whether  they  will  receive
+              The number of non-whitelisted clients that  can  be
+              waiting  for  a  decision whether they will receive
               service from a real SMTP server process.
 
        <b><a href="postconf.5.html#postscreen_watchdog_timeout">postscreen_watchdog_timeout</a> (10s)</b>
-              How  much  time a <a href="postscreen.8.html"><b>postscreen</b>(8)</a> process may take to
-              respond to an SMTP client command or to  perform  a
+              How much time a <a href="postscreen.8.html"><b>postscreen</b>(8)</a> process may  take  to
+              respond  to  an SMTP client command or to perform a
               cache operation before it is terminated by a built-
               in watchdog timer.
 
 <b>STARTTLS CONTROLS</b>
        <b><a href="postconf.5.html#postscreen_tls_security_level">postscreen_tls_security_level</a> ($<a href="postconf.5.html#smtpd_tls_security_level">smtpd_tls_security_level</a>)</b>
-              The SMTP TLS security level for  the  <a href="postscreen.8.html"><b>postscreen</b>(8)</a>
-              server;  when  a non-empty value is specified, this
+              The  SMTP  TLS security level for the <a href="postscreen.8.html"><b>postscreen</b>(8)</a>
+              server; when a non-empty value is  specified,  this
               overrides       the       obsolete       parameters
               <a href="postconf.5.html#postscreen_use_tls">postscreen_use_tls</a> and <a href="postconf.5.html#postscreen_enforce_tls">postscreen_enforce_tls</a>.
 
 <b>OBSOLETE STARTTLS SUPPORT CONTROLS</b>
-       These  parameters  are  supported  for  compatibility with
+       These parameters  are  supported  for  compatibility  with
        <a href="smtpd.8.html"><b>smtpd</b>(8)</a> legacy parameters.
 
        <b><a href="postconf.5.html#postscreen_use_tls">postscreen_use_tls</a> ($<a href="postconf.5.html#smtpd_use_tls">smtpd_use_tls</a>)</b>
-              Opportunistic TLS:  announce  STARTTLS  support  to
-              SMTP  clients,  but do not require that clients use
+              Opportunistic  TLS:  announce  STARTTLS  support to
+              SMTP clients, but do not require that  clients  use
               TLS encryption.
 
        <b><a href="postconf.5.html#postscreen_enforce_tls">postscreen_enforce_tls</a> ($<a href="postconf.5.html#smtpd_enforce_tls">smtpd_enforce_tls</a>)</b>
-              Mandatory TLS: announce STARTTLS  support  to  SMTP
-              clients,  and  require that clients use TLS encryp-
+              Mandatory  TLS:  announce  STARTTLS support to SMTP
+              clients, and require that clients use  TLS  encryp-
               tion.
 
 <b>MISCELLANEOUS CONTROLS</b>
        <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#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#command_directory">command_directory</a> (see 'postconf -d' output)</b>
-              The location of  all  postfix  administrative  com-
+              The  location  of  all  postfix administrative com-
               mands.
 
        <b><a href="postconf.5.html#ipc_timeout">ipc_timeout</a> (3600s)</b>
@@ -329,24 +332,24 @@ POSTSCREEN(8)                                                    POSTSCREEN(8)
               over an internal communication channel.
 
        <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#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#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".
 
 <b>SEE ALSO</b>
@@ -359,12 +362,12 @@ POSTSCREEN(8)                                                    POSTSCREEN(8)
        <a href="POSTSCREEN_README.html">POSTSCREEN_README</a>, Postfix Postscreen Howto
 
 <b>LICENSE</b>
-       The  Secure  Mailer  license must be distributed with this
+       The Secure Mailer license must be  distributed  with  this
        software.
 
 <b>HISTORY</b>
-       Many ideas in <a href="postscreen.8.html"><b>postscreen</b>(8)</a> were explored in earlier  work
-       by  Michael Tokarev, in OpenBSD spamd, and in MailChannels
+       Many  ideas in <a href="postscreen.8.html"><b>postscreen</b>(8)</a> were explored in earlier work
+       by Michael Tokarev, in OpenBSD spamd, and in  MailChannels
        Traffic Control.
 
 <b>AUTHOR(S)</b>

diff --git a/postfix/man/man8/postscreen.8 b/postfix/man/man8/postscreen.8
index f8acab13562ccd73a68e2b2654acf0b20d6444c9..67b09c982157dd086d94e25cdbe802b9eb199a3c 100644 (file)
--- a/postfix/man/man8/postscreen.8
+++ b/postfix/man/man8/postscreen.8
@@ -63,7 +63,7 @@ RFC 2920 (SMTP Pipelining)
 RFC 3207 (STARTTLS command)
 RFC 3461 (SMTP DSN Extension)
 RFC 3463 (Enhanced Status Codes)
-RFC 5321 (SMTP protocol, including multi-line 220 greetings)
+RFC 5321 (SMTP protocol, including multi-line 220 banners)
 .SH DIAGNOSTICS
 .ad
 .fi
@@ -71,6 +71,9 @@ Problems and transactions are logged to \fBsyslogd\fR(8).
 .SH BUGS
 .ad
 .fi
+The \fBpostscreen\fR(8) server does not yet implement
+the \fBsoft_bounce\fR feature.
+
 The \fBpostscreen\fR(8) built-in SMTP protocol engine
 currently does not announce support for AUTH, XCLIENT or
 XFORWARD.

diff --git a/postfix/src/global/mail_version.h b/postfix/src/global/mail_version.h
index c1e99f217368d78cbd9bb0c57208272cc4b79ab9..c7ae8e44ef6fd230e4685c736737636a9c5d6d64 100644 (file)
--- a/postfix/src/global/mail_version.h
+++ b/postfix/src/global/mail_version.h
@@ -20,7 +20,7 @@
   * Patches change both the patchlevel and the release date. Snapshots have no
   * patchlevel; they change the release date only.
   */
-#define MAIL_RELEASE_DATE      "20110102"
+#define MAIL_RELEASE_DATE      "20110103"
 #define MAIL_VERSION_NUMBER    "2.8"
 
 #ifdef SNAPSHOT

diff --git a/postfix/src/postscreen/Makefile.in b/postfix/src/postscreen/Makefile.in
index b856fc5ff7052c4f6722be362e065439b96983a4..5e41241a9c8fc9f820d6c01076131fbbcfa8a24b 100644 (file)
--- a/postfix/src/postscreen/Makefile.in
+++ b/postfix/src/postscreen/Makefile.in
@@ -180,6 +180,7 @@ postscreen_send.o: ../../include/dict_cache.h
 postscreen_send.o: ../../include/events.h
 postscreen_send.o: ../../include/htable.h
 postscreen_send.o: ../../include/iostuff.h
+postscreen_send.o: ../../include/mail_params.h
 postscreen_send.o: ../../include/match_list.h
 postscreen_send.o: ../../include/match_ops.h
 postscreen_send.o: ../../include/msg.h

diff --git a/postfix/src/postscreen/postscreen.c b/postfix/src/postscreen/postscreen.c
index f40f25e01ece02942564149d0116b7ec04b2ebe1..5809554612db9283a27d3c54fe4828dfa2faf7cb 100644 (file)
--- a/postfix/src/postscreen/postscreen.c
+++ b/postfix/src/postscreen/postscreen.c
@@ -53,10 +53,13 @@
 /*     RFC 3207 (STARTTLS command)
 /*     RFC 3461 (SMTP DSN Extension)
 /*     RFC 3463 (Enhanced Status Codes)
-/*     RFC 5321 (SMTP protocol, including multi-line 220 greetings)
+/*     RFC 5321 (SMTP protocol, including multi-line 220 banners)
 /* DIAGNOSTICS
 /*     Problems and transactions are logged to \fBsyslogd\fR(8).
 /* BUGS
+/*     The \fBpostscreen\fR(8) server does not yet implement
+/*     the \fBsoft_bounce\fR feature.
+/*
 /*     The \fBpostscreen\fR(8) built-in SMTP protocol engine
 /*     currently does not announce support for AUTH, XCLIENT or
 /*     XFORWARD.
@@ -542,9 +545,10 @@ static void psc_service(VSTREAM *smtp_client_stream,
     if (getpeername(vstream_fileno(smtp_client_stream), (struct sockaddr *)
                    & addr_storage, &addr_storage_len) < 0) {
        msg_warn("getpeername: %m -- dropping this connection");
-       psc_send_reply(vstream_fileno(smtp_client_stream),
-                      "unknown_address", "unknown_port",
-                      "421 4.3.2 No system resources\r\n");
+       /* Best effort - if this non-blocking write(2) fails, so be it. */
+       (void) write(vstream_fileno(smtp_client_stream),
+                    "421 4.3.2 No system resources\r\n",
+                    sizeof("421 4.3.2 No system resources\r\n") - 1);
        PSC_SERVICE_DISCONNECT_AND_RETURN(smtp_client_stream);
     }
 
@@ -558,9 +562,10 @@ static void psc_service(VSTREAM *smtp_client_stream,
        msg_warn("cannot convert client address/port to string: %s"
                 " -- dropping this connection",
                 MAI_STRERROR(aierr));
-       psc_send_reply(vstream_fileno(smtp_client_stream),
-                      "unknown_address", "unknown_port",
-                      "421 4.3.2 No system resources\r\n");
+       /* Best effort - if this non-blocking write(2) fails, so be it. */
+       (void) write(vstream_fileno(smtp_client_stream),
+                    "421 4.3.2 No system resources\r\n",
+                    sizeof("421 4.3.2 No system resources\r\n") - 1);
        PSC_SERVICE_DISCONNECT_AND_RETURN(smtp_client_stream);
     }
     if (strncasecmp("::ffff:", smtp_client_addr.buf, 7) == 0)

diff --git a/postfix/src/postscreen/postscreen.h b/postfix/src/postscreen/postscreen.h
index c0885be85890656b9c57be2fd0d62f60d187ee1c..f5b894e3d93c5dbcadbafe28156796b0c422346a 100644 (file)
--- a/postfix/src/postscreen/postscreen.h
+++ b/postfix/src/postscreen/postscreen.h
@@ -44,6 +44,7 @@ typedef struct {
     char   *smtp_client_port;          /* client port */
     int     client_concurrency;                /* per-client */
     const char *final_reply;           /* cause for hanging up */
+    VSTRING *send_buf;                 /* pending output */
     /* Test context. */
     struct timeval start_time;         /* start of current test */
     const char *test_name;             /* name of current test */
@@ -438,12 +439,8 @@ extern void psc_hangup_event(PSC_STATE *);
  /*
   * postscreen_send.c
   */
-#define PSC_SEND_REPLY(state, text) \
-    psc_send_reply(vstream_fileno((state)->smtp_client_stream), \
-                 (state)->smtp_client_addr, \
-                 (state)->smtp_client_port, \
-                 (text))
-extern int psc_send_reply(int, const char *, const char *, const char *);
+#define PSC_SEND_REPLY psc_send_reply  /* legacy macro */
+extern int psc_send_reply(PSC_STATE *, const char *);
 extern void psc_send_socket(PSC_STATE *);
 
  /*

diff --git a/postfix/src/postscreen/postscreen_send.c b/postfix/src/postscreen/postscreen_send.c
index 7b7edc35004af2e08f45fcf6851511828f732449..d74e6004982bad7a1d0fdb93f8da6cf63b659563 100644 (file)
--- a/postfix/src/postscreen/postscreen_send.c
+++ b/postfix/src/postscreen/postscreen_send.c
@@ -6,13 +6,12 @@
 /* SYNOPSIS
 /*     #include <postscreen.h>
 /*
-/*     int     psc_send_reply(client_fd, client_addr, client_port, text)
-/*     int     client_fd;
-/*     const char *client_addr;
-/*     const char *client_port;
+/*     int     psc_send_reply(state, text)
+/*     PSC_STATE *state;
 /*     const char *text;
 /*
 /*     int     PSC_SEND_REPLY(state, text)
+/*     PSC_STATE *state;
 /*     const char *text;
 /*
 /*     void    psc_send_socket(state)
@@ -23,9 +22,8 @@
 /*     a warning (except EPIPE) with the client address and port,
 /*     and returns a non-zero result (all errors including EPIPE).
 /*
-/*     PSC_SEND_REPLY() is a convenience wrapper for psc_send_reply().
-/*     It is an unsafe macro that evaluates its arguments multiple
-/*     times.
+/*     PSC_SEND_REPLY() is a legacy wrapper for psc_send_reply().
+/*     It will eventually be replaced by its expansion.
 /*
 /*     psc_send_socket() sends the specified socket to the real
 /*     Postfix SMTP server. The socket is delivered in the background.
@@ -57,6 +55,10 @@
 #include <iostuff.h>
 #include <connect.h>
 
+/* Global library. */
+
+#include <mail_params.h>
+
 /* Application-specific. */
 
 #include <postscreen.h>
@@ -67,28 +69,53 @@
   */
 #define PSC_SEND_SOCK_CONNECT_TIMEOUT  1
 #define PSC_SEND_SOCK_NOTIFY_TIMEOUT   100
-#define PSC_SEND_TEXT_TIMEOUT          1
 
 /* psc_send_reply - send reply to remote SMTP client */
 
-int     psc_send_reply(int smtp_client_fd, const char *smtp_client_addr,
-                            const char *smtp_client_port, const char *text)
+int     psc_send_reply(PSC_STATE *state, const char *text)
 {
+    int     start;
     int     ret;
 
     if (msg_verbose)
-       msg_info("> [%s]:%s: %.*s", smtp_client_addr, smtp_client_port,
-                (int) strlen(text) - 2, text);
+       msg_info("> [%s]:%s: %.*s", state->smtp_client_addr,
+                state->smtp_client_port, (int) strlen(text) - 2, text);
+
+    /*
+     * Append the new text to earlier text that could not be sent because the
+     * output was throttled.
+     */
+    start = VSTRING_LEN(state->send_buf);
+    vstring_strcat(state->send_buf, text);
 
     /*
-     * XXX Need to make sure that the TCP send buffer is large enough for any
-     * response, so that a nasty client can't cause this process to block.
+     * XXX For soft_bounce support, it is not sufficient to fix replies here.
+     * We also need to fix the REJECT messages that are logged by the dummy
+     * SMTP engine. Those messages are set with the PSC_DROP_SESSION_STATE
+     * and PSC_ENFORCE_SESSION_STATE macros, and we should not mess up all
+     * the code that invokes those macros.
      */
-    ret = (write_buf(smtp_client_fd, text, strlen(text),
-                    PSC_SEND_TEXT_TIMEOUT) < 0);
-    if (ret != 0 && errno != EPIPE)
-       msg_warn("write [%s]:%s: %m", smtp_client_addr, smtp_client_port);
-    return (ret);
+#if 0
+    if (var_soft_bounce) {
+       if (text[0] == '5')
+           STR(state->send_buf)[start + 0] = '4';
+       if (text[4] == '5')
+           STR(state->send_buf)[start + 4] = '4';
+    }
+#endif
+
+    /*
+     * Do a best effort sending text, but don't block when the output is
+     * throttled by a hostile peer.
+     */
+    ret = write(vstream_fileno(state->smtp_client_stream),
+               STR(state->send_buf), LEN(state->send_buf));
+    if (ret > 0)
+       vstring_truncate(state->send_buf, ret - LEN(state->send_buf));
+    if (ret < 0 && errno != EAGAIN && errno != EPIPE)
+       msg_warn("write [%s]:%s: %m", state->smtp_client_addr,
+                state->smtp_client_port);
+    return (ret < 0 && errno != EAGAIN);
 }
 
 /* psc_send_socket_close_event - file descriptor has arrived or timeout */

diff --git a/postfix/src/postscreen/postscreen_smtpd.c b/postfix/src/postscreen/postscreen_smtpd.c
index 8b529bc773742bd5f966b4118a560f2c27f5c1f1..07ebc8ca8ea56468b6b1dda94b1db4879cb0726e 100644 (file)
--- a/postfix/src/postscreen/postscreen_smtpd.c
+++ b/postfix/src/postscreen/postscreen_smtpd.c
@@ -260,7 +260,8 @@ static int psc_helo_cmd(PSC_STATE *state, char *args)
 
 /* psc_smtpd_format_ehlo_reply - format EHLO response */
 
-static void psc_smtpd_format_ehlo_reply(VSTRING *buf, int discard_mask)
+static void psc_smtpd_format_ehlo_reply(VSTRING *buf, int discard_mask
+       /*, const char *sasl_mechanism_list */)
 {
     const char *myname = "psc_smtpd_format_ehlo_reply";
     int     saved_len = 0;
@@ -1063,6 +1064,9 @@ void    psc_smtpd_init(void)
        case TLS_LEV_SECURE:
        case TLS_LEV_VERIFY:
        case TLS_LEV_FPRINT:
+           msg_warn("%s: unsupported TLS level \"%s\", using \"encrypt\"",
+                    VAR_PSC_TLS_LEVEL, var_psc_tls_level);
+           /* FALLTHROUGH */
        case TLS_LEV_ENCRYPT:
            var_psc_enforce_tls = var_psc_use_tls = 1;
            break;

diff --git a/postfix/src/postscreen/postscreen_state.c b/postfix/src/postscreen/postscreen_state.c
index 42e2f0aed787abeadca6fde138252332e16705a1..97ffae13240c8b89097431a3064d058153437c80 100644 (file)
--- a/postfix/src/postscreen/postscreen_state.c
+++ b/postfix/src/postscreen/postscreen_state.c
@@ -153,6 +153,7 @@ PSC_STATE *psc_new_session_state(VSTREAM *stream,
     state->smtp_server_fd = (-1);
     state->smtp_client_addr = mystrdup(addr);
     state->smtp_client_port = mystrdup(port);
+    state->send_buf = vstring_alloc(100);
     state->test_name = "TEST NAME HERE";
     state->dnsbl_reply = 0;
     state->final_reply = "421 4.3.2 Service currently unavailable\r\n";
@@ -212,6 +213,8 @@ void    psc_free_session_state(PSC_STATE *state)
        close(state->smtp_server_fd);
        psc_post_queue_length--;
     }
+    if (state->send_buf != 0)
+       state->send_buf = vstring_free(state->send_buf);
     myfree(state->smtp_client_addr);
     myfree(state->smtp_client_port);
     if (state->dnsbl_reply)

diff --git a/postfix/src/tlsproxy/tlsproxy.c b/postfix/src/tlsproxy/tlsproxy.c
index 4e0b350eb81ded885feb86336682d563c23fa661..a7351e6a31d99b7a590c55474edaa07def6701cf 100644 (file)
--- a/postfix/src/tlsproxy/tlsproxy.c
+++ b/postfix/src/tlsproxy/tlsproxy.c
@@ -293,6 +293,7 @@ int     var_tlsp_watchdog;
 static TLS_APPL_STATE *tlsp_server_ctx;
 static int ask_client_cert;
 static int enforce_tls;
+static int tlsp_tls_enforce_tls;
 
  /*
   * SLMs.
@@ -625,9 +626,13 @@ static void tlsp_ciphertext_event(int event, char *context)
     if (event == EVENT_READ || event == EVENT_WRITE) {
        tlsp_strategy(state);
     } else {
-       msg_warn("read/write %s for %s",
-                event == EVENT_TIME ? "timeout" : "error",
-                state->remote_endpt);
+       if (event == EVENT_TIME && state->ssl_last_err == SSL_ERROR_NONE)
+           msg_warn("deadlock on plaintext stream for %s",
+                    state->remote_endpt);
+       else
+           msg_warn("read/write %s for %s",
+                    event == EVENT_TIME ? "timeout" : "error",
+                    state->remote_endpt);
        tlsp_state_free(state);
     }
 }
@@ -645,8 +650,6 @@ static void tlsp_start_tls(TLSP_STATE *state)
      * going to sanitize this because doing so surely will break things in
      * unexpected ways.
      */
-    state->tls_use_tls = var_tlsp_use_tls | var_tlsp_enforce_tls;
-    state->tls_enforce_tls = var_tlsp_enforce_tls;
 
     /*
      * Perform the before-handshake portion of the per-session initalization.
@@ -680,7 +683,7 @@ static void tlsp_start_tls(TLSP_STATE *state)
                         log_level = var_tlsp_tls_loglevel,
                         timeout = 0,           /* unused */
                         requirecert = (var_tlsp_tls_req_ccert
-                                       && state->tls_enforce_tls),
+                                       && tlsp_tls_enforce_tls),
                         serverid = state->service,
                         namaddr = state->remote_endpt,
                         cipher_grade = cipher_grade,
@@ -894,7 +897,39 @@ static void pre_jail_init(char *unused_name, char **unused_argv)
      * The code in this routine is pasted literally from smtpd(8). I am not
      * going to sanitize this because doing so surely will break things in
      * unexpected ways.
-     * 
+     */
+    if (*var_tlsp_tls_level) {
+       switch (tls_level_lookup(var_tlsp_tls_level)) {
+       default:
+           msg_fatal("Invalid TLS level \"%s\"", var_tlsp_tls_level);
+           /* NOTREACHED */
+           break;
+       case TLS_LEV_SECURE:
+       case TLS_LEV_VERIFY:
+       case TLS_LEV_FPRINT:
+           msg_warn("%s: unsupported TLS level \"%s\", using \"encrypt\"",
+                    VAR_TLSP_TLS_LEVEL, var_tlsp_tls_level);
+           /* FALLTHROUGH */
+       case TLS_LEV_ENCRYPT:
+           var_tlsp_enforce_tls = var_tlsp_use_tls = 1;
+           break;
+       case TLS_LEV_MAY:
+           var_tlsp_enforce_tls = 0;
+           var_tlsp_use_tls = 1;
+           break;
+       case TLS_LEV_NONE:
+           var_tlsp_enforce_tls = var_tlsp_use_tls = 0;
+           break;
+       }
+    }
+    tlsp_tls_enforce_tls = var_tlsp_enforce_tls;
+    if (!(var_tlsp_use_tls || var_tlsp_enforce_tls)) {
+       msg_warn("TLS service is requested, but disabled with %s or %s",
+                VAR_TLSP_TLS_LEVEL, VAR_TLSP_USE_TLS);
+       return;
+    }
+
+    /*
      * Load TLS keys before dropping privileges.
      * 
      * Can't use anonymous ciphers if we want client certificates. Must use

diff --git a/postfix/src/tlsproxy/tlsproxy.h b/postfix/src/tlsproxy/tlsproxy.h
index e18e38a75b88db74fc71bcc6b6a86dd769911270..0c4d129c7a7361634c3c197036bc714f58f35ad5 100644 (file)
--- a/postfix/src/tlsproxy/tlsproxy.h
+++ b/postfix/src/tlsproxy/tlsproxy.h
@@ -33,8 +33,6 @@ typedef struct {
     char   *remote_endpt;              /* printable remote endpoint */
     TLS_SESS_STATE *tls_context;       /* llibtls state */
     int     ssl_last_err;              /* TLS I/O state */
-    int     tls_use_tls;               /* legacy libtls API */
-    int     tls_enforce_tls;           /* legacy libtls API */
 } TLSP_STATE;
 
 #define TLSP_FLAG_DO_HANDSHAKE (1<<0)

diff --git a/postfix/src/util/vstring.c b/postfix/src/util/vstring.c
index 783730d9290a8de379b3280b0875772ff8861317..f7794ae7405bacd63c379901d4b246da1aba8f72 100644 (file)
--- a/postfix/src/util/vstring.c
+++ b/postfix/src/util/vstring.c
@@ -173,7 +173,8 @@
 /*     arguments more than once. The result is NOT null-terminated.
 /*
 /*     vstring_truncate() truncates the named string to the specified
-/*     length. The operation has no effect when the string is shorter.
+/*     length. If length is negative, the trailing portion is kept.
+/*     The operation has no effect when the string is shorter.
 /*     The string is not null-terminated.
 /*
 /*     VSTRING_RESET() is a macro that resets the write position of its
@@ -393,8 +394,13 @@ void    vstring_ctl(VSTRING *vp,...)
 
 VSTRING *vstring_truncate(VSTRING *vp, ssize_t len)
 {
-    if (len < 0)
-       msg_panic("vstring_truncate: bad length %ld", (long) len);
+    ssize_t move;
+
+    if (len < 0) {
+       len = (-len);
+       if ((move = VSTRING_LEN(vp) - len) > 0)
+           memmove(vstring_str(vp), vstring_str(vp) + move, len);
+    }
     if (len < VSTRING_LEN(vp))
        VSTRING_AT_OFFSET(vp, len);
     return (vp);