(Defaults.py.in): Added USE_ENVELOPE_SENDER variable, which is set to

1 by default.  This instructs the MailList.Post() method to use first
the envelope sender (i.e. Unix "From " line) and then the From:
header.  However, this breaks member_only_posting on some systems (for
reasons unknown).  Set this variable to 0 in mm_cfg.py to use only the
From: header, although this can open the list up to spam.

(MailList.py): in Post(), check USE_ENVELOPE_SENDER to see if
GetEnvelopeSender() should be called.

(FAQ): Add a question refering to USE_ENVELOPE_SENDER.

3 files changed, 44 insertions, 4 deletions

diff --git a/FAQ b/FAQ
index a4c82babe..9dd1ec71d 100644
--- a/FAQ
+++ b/FAQ
@@ -108,6 +108,28 @@ FREQUENTLY ASKED QUESTIONS
      . run $prefix/bin/arch <listname> 
 	   $prefix/archives/private/<listname>.mbox/<listname>.mbox
 
+9. I set member_posting_only to yes because I want to limit posts to
+   members only, however it seems like all messages coming from
+   members are held for approval.
+
+   There appears to be a problem on some systems where the envelope
+   sender (e.g. the Unix "From " line) is set incorrectly.  This will
+   cause a negative match when checking to see if the sender is a
+   member of the list.  Mailman defaults to using the envelope sender
+   before the sender (i.e. "From:" header) because the former is set
+   by the SMTP agent while the latter is easily spoofable by the end
+   user.
+
+   However, if you are having this problem, you may opt to favor the
+   From: header over the envelope sender.  Do this by adding the
+   following line to your mm_cfg.py file:
+
+   USE_ENVELOPE_SENDER=0
+
+   However, read the comments about this variable in the Defaults.py
+   file first.
+
+
 
 Local Variables:
 mode: text
diff --git a/Mailman/Defaults.py.in b/Mailman/Defaults.py.in
index aca288181..a281b2890 100644
--- a/Mailman/Defaults.py.in
+++ b/Mailman/Defaults.py.in
@@ -81,6 +81,20 @@ USE_CRYPT         = 1
 
 			 # General Defaults #
 
+# When allowing only members to post to a mailing list, how is the sender of
+# the message determined?  If this variable is set to 1, then first the
+# message's envelope sender is used, with a fallback to the sender if there is 
+# no envelope sender.  Set this variable to 0 to always use the sender.
+#
+# The envelope sender is set by the SMTP delivery and is thus less easily
+# spoofed than the sender, which is typically just taken from the From: header 
+# and thus easily spoofed by the end-user.  However, sometimes the envelope
+# sender isn't set correctly and this will manifest itself by postings being
+# held for approval even if they appear to come from a list member.  If you
+# are having this problem, set this variable to 0, but understand that some
+# spoofed messages may get through.
+USE_ENVELOPE_SENDER = 1
+
 # When true, mailman will consider user@host.domain to be the same address
 # as user@domain.  If set to 0, mailman will consider user@host.domain to 
 # be the same address as user@Host.DoMain, but different than user@domain.
diff --git a/Mailman/MailList.py b/Mailman/MailList.py
index acb2a12b5..733d67e0e 100644
--- a/Mailman/MailList.py
+++ b/Mailman/MailList.py
@@ -1041,9 +1041,13 @@ class MailList(MailCommandHandler, HTMLFormatter, Deliverer, ListAdmin,
         msgapproved = self.ExtractApproval(msg)
         if not approved:
             approved = msgapproved
-        sender = msg.GetEnvelopeSender()
+        sender = None
+        if mm_cfg.USE_ENVELOPE_SENDER:
+            sender = msg.GetEnvelopeSender()
         if not sender:
             sender = msg.GetSender()
+##        sys.stderr.write('envsend: %s, sender: %s\n' %
+##                         (msg.GetEnvelopeSender(), msg.GetSender()))
 	# If it's the admin, which we know by the approved variable,
 	# we can skip a large number of checks.
 	if not approved:
@@ -1139,9 +1143,9 @@ class MailList(MailCommandHandler, HTMLFormatter, Deliverer, ListAdmin,
 			  subj, re.I):
 	    msg.SetHeader('Subject', '%s%s' % (prefix, subj))
         if self.anonymous_list:
-	  del msg['reply-to']
-	  del msg['sender']
-	  msg.SetHeader('From', self.GetAdminEmail())
+            del msg['reply-to']
+            del msg['sender']
+            msg.SetHeader('From', self.GetAdminEmail())
 	if self.digestable:
 	    self.SaveForDigest(msg)
 	if self.archive: