pullimap: Fix mangling of data lines starting with a dot.

Some LMTP servers, Dovecot's in particular, trims leading dots that are
not doubled (e.g. “.foo” would become “foo”).  In RFC 5322 sec. 4.5.2
explicitly says that when an RFC 5322 line starts with a '.', the
character needs to be doubled.

4 files changed, 65 insertions, 15 deletions

diff --git a/Changelog b/Changelog
index 1a80ebf..4a18c52 100644
--- a/Changelog
+++ b/Changelog
@@ -107,6 +107,8 @@ interimap (0.5) upstream;
    for other servers the number remains 1).
  - interimap: gracefully ignore messages with a NIL RFC822 attribute.
  - pullimap: treat messages with a NIL RFC822 attribute as empty.
+ - pullimap: fix mangling of data lines starting with a dot (when an RFC
+   5322 line starts with a '.', double it).
 
  -- Guilhem Moulin <guilhem@fripost.org>  Fri, 10 May 2019 00:58:14 +0200
 
diff --git a/pullimap b/pullimap
index fbe300e..ee2168d 100755
--- a/pullimap
+++ b/pullimap
@@ -175,17 +175,18 @@ sub sendmail($$) {
         my $length = length($$rfc822);
         while ((my $end = index($$rfc822, "\r\n", $offset) + 2) != 1) {
             my $line = substr($$rfc822, $offset, $end-$offset);
-            # RFC 5321 section 4.5.2: the character sequence "\r\n.\r\n"
-            # ends the mail text and cannot be sent by the user
-            $SMTP->print($line eq ".\r\n" ? "..\r\n" : $line) or die;
+            # RFC 5321 sec. 4.5.2: if the line starts with a dot, double it
+            $line = ".".$line if substr($line, 0, 1) eq ".";
+            $SMTP->print($line) or die;
             $offset = $end;
         }
         if ($offset < $length) {
             # the last line did not end with "\r\n"; add it in order to
             # have the receiving SMTP server recognize the "end of data"
-            # condition.  See RFC 5321 section 4.1.1.4
+            # condition.  See RFC 5321 sec. 4.1.1.4
             my $line = substr($$rfc822, $offset);
-            $SMTP->print(($line eq "." ? ".." : $line), "\r\n") or die;
+            $line = ".".$line if substr($line, 0, 1) eq ".";
+            $SMTP->print($line, "\r\n") or die;
         }
         $SMTP->printflush(".\r\n") or die;
     }
diff --git a/tests/pullimap/t b/tests/pullimap/t
index 7ae0c5f..79da3e0 100644
--- a/tests/pullimap/t
+++ b/tests/pullimap/t
@@ -6,12 +6,9 @@ step_start "\`pullimap --idle\` refuses to create the state file"
 ! pullimap --idle "remote" || error
 step_done
 
-# make sure remote UIDs are 11-bytes long
-doveadm -u "remote" mailbox update --min-next-uid 1000000000 "$MAILBOX"
-
 # compare mailboxes; can't compare the RFC 3501 TEXT as LMTP adds a
 # Received: header.
-# TODO unset lmtp_add_received_header once avaisable in Sid:
+# TODO unset lmtp_add_received_header once available in sid:
 # https://doc.dovecot.org/settings/dovecot_core_settings/#lmtp-add-received-header
 list_mails_sha256() {
     local u="$1" guid uid
@@ -26,7 +23,59 @@ check() {
         <( list_mails_sha256 "remote" ) \
         || error "mailboxes differ"
 }
+message_from() {
+    local date="$(date +"%s.%N")" sender="$1"
+    cat <<-EOF
+		From: $sender
+		To: <me@example.net>
+		Date: $(date -R -d@"$date")
+		Message-ID: <$date@example.net>
+
+	EOF
+    xxd -ps -l8 /dev/urandom
+}
 
+step_start "Quote envelope sender address"
+declare -a senders=("sender" "first.last" "foo-bar" \"\" "\"x\\\" #&\\\\y\"")
+for s in "${senders[@]}"; do
+    message_from "$s@example.net" | deliver -u "remote" -- -m "$MAILBOX"
+done
+pullimap "remote" || error
+check
+for s in "${senders[@]}"; do
+    grep -F " from <$s@example.net> " <"$STDERR" || error "$s"
+done
+step_done
+
+step_start "Mail without data"
+deliver -u "remote" -- -m "$MAILBOX" </dev/null
+pullimap "remote" || error
+check
+step_done
+
+step_start "Dot-leading lines"
+deliver -u "remote" -- -m "$MAILBOX" <<-EOF
+	From: alice@example.net
+	To: bob@example.net
+	Date: $(date -R)
+    Message-ID: <$(xxd -ps -l8 /dev/urandom)@example.net>
+
+	foo
+	.
+	.bar
+	..baz
+EOF
+# we can't add a test for message data not ending with CRLF, because the
+# LMTP/SMTP client needs to add a CRLF so local and remote message
+# bodies would differ.  that said, while such a message could be added
+# by IMAP and LDA, it's not valid for SMTP (RFC 5321 sec. 4.1.1.4)
+pullimap "remote" || error
+check
+step_done
+
+
+# make sure remote UIDs are 11-bytes long
+doveadm -u "remote" mailbox update --min-next-uid 1000000000 "$MAILBOX"
 
 # Add some messages and sync
 step_start "Fetching messages"
@@ -40,11 +89,11 @@ check
 # same thing, but with some missing messages
 for ((i = 0; i < N; i+=2)); do
     sample_message | deliver -u "remote" -- -m "$MAILBOX"
-    deliver -u "remote" -- -m "$MAILBOX" </dev/null # even seqnum
+    deliver -u "remote" -- -m "$MAILBOX" </dev/null # odd seqnum
 done
 for ((i = 0; i < N; i+=2)); do
     # expunge every other message
-    doveadm -u "remote" expunge mailbox "$MAILBOX" $((N-i+32))
+    doveadm -u "remote" expunge mailbox "$MAILBOX" $((N-i+32+7))
     sample_message | deliver -u "remote" -- -m "$MAILBOX"
 done
 
diff --git a/tests/run b/tests/run
index 30d20f9..a34e4a9 100755
--- a/tests/run
+++ b/tests/run
@@ -235,11 +235,9 @@ sqlite3() {
 # Sample (random) message
 sample_message() {
     local date="$(date +"%s.%N")"
-    # also try non-conventional addresses for pullimap
-    local sender="$(shuf -n1 -e "sender" "first.last" "foo-bar" \"\" "\"x\\\" #&\\\\y\"" )"
     cat <<-EOF
-		From: <$sender@example.net>
-		To: <recipient@example.net>
+		From: <$(xxd -ps -l6 /dev/urandom)@example.net>
+		To: <me@example.net>
 		Date: $(date -R -d@"$date")
 		Message-ID: <$date@example.net>