Fix #180: Rename authentication methods

This is a really dirt fix for issue #180. It will replace "well-known"
enumerated plugin names with SASL mechanism names. While this is more of
a "bandage" than the actual proper fix, I have currently found no better
ways to do it.

Most likely this issue will rise up again with another SASL plugin and
we will deal with it then. At this stage, it should cover most of the
use cases transparently.

scripts/common-run.sh

@@ -418,7 +418,7 @@ postfix_setup_xoauth2_post_setup() {
 			# Ubuntu/Debian have renamed pluginviewer to saslpluginviewer so this fails with those distros.
 			plugin_viewer="saslpluginviewer"
 		fi
-		other_plugins="$(${plugin_viewer} -c | grep Plugin | cut -d\  -f2 | cut -c2- | rev | cut -c2- | rev | grep -v EXTERNAL | grep -v sasl-xoauth2 | tr '\n' ',' | rev | cut -c2- | rev)"
+		other_plugins="$(${plugin_viewer} -c | grep Plugin | cut -d\  -f2 | cut -c2- | rev | cut -c2- | rev | grep -v EXTERNAL | grep -v sasl-xoauth2 | tr '\n' ',' | rev | cut -c2- | rev | convert_plugin_names_to_filter_names)"
 		do_postconf -e "smtp_sasl_mechanism_filter=${other_plugins}"
 	fi
 }

scripts/common.sh

@@ -227,4 +227,61 @@ zone_info_dir() {
 	return
 }
 
+###################################################################
+# Remove leading and trailing whitespace from string
+###################################################################
+trim() {
+	local var
+	IFS='' read -d -r var
+	#var="$(<&1)"
+	# remove leading whitespace characters
+	var="${var#"${var%%[![:space:]]*}"}"
+	# remove trailing whitespace characters
+	var="${var%"${var##*[![:space:]]}"}"
+	printf '%s' "${var}"
+}
+
+###################################################################
+# Potential fix for #180. Plugin names do not neccessarily match 
+# filter names.
+#
+# This is an utility method which converts SASL plugin names into
+# filter names. There's no reliable way to guess this, so the names
+# have been hardcoded here.
+#
+# INPUT:
+# The method expects as an input a list of plugin names, comma
+# separated.
+#
+# OUTPUT:
+# The list of plugin names, comma separated.
+###################################################################
+convert_plugin_names_to_filter_names() {
+	local line first value lowercase
+	while IFS=$',' read -ra line; do
+		for value in "${line[@]}"; do
+			value="$(printf '%s' "${value}" | trim)"
+			if [[ -z "${value}" ]]; then
+				continue;
+			fi
+
+			if [[ -z "${first}" ]]; then
+				first="0"
+			else
+				printf '%s' ','
+			fi
+
+			lowercase="${value,,}"
+
+			if [[ "${lowercase}" == "digestmd5" ]]; then
+				printf '%s' 'DIGEST-MD5'
+			elif [[ "${lowercase}" == "crammd5" ]]; then
+				printf '%s' 'CRAM-MD5'
+			else
+				printf '%s' "${value}"
+			fi
+		done
+	done
+}
+
 export reset green yellow orange orange_emphasis lightblue red gray emphasis underline

unit-tests/027_convert_plugin_names_to_filter_names.bats

@@ -0,0 +1,35 @@
+#!/usr/bin/env bats
+
+load /code/scripts/common.sh
+
+assert_equals() {
+	local expected="$1"
+	local actual="$2"
+	if [[ "${expected}" != "${actual}" ]]; then
+		echo "Expected: \"${expected}\". Got: \"${actual}\"." >&2
+		exit 1
+	fi
+}
+
+@test "check if trim works properly" {
+	assert_equals "bar" "$(echo "bar" | trim)"
+	assert_equals "foo bar" "$(echo "foo bar" | trim)"
+	assert_equals "foo bar" "$(echo "     foo bar" | trim)"
+	assert_equals "foo bar" "$(echo "foo bar       " | trim)"
+	assert_equals "foo bar" "$(echo "          foo bar       " | trim)"
+	assert_equals "foo bar" "$(printf '%s' "			foo bar" | trim)"
+	assert_equals "foo bar" "$(printf '%s' $'\t\tfoo bar\r\n' | trim)"
+	assert_equals "foo bar" "$(printf '%s' $'		   	  foo bar\r\n' | trim)"
+}
+
+@test "check if convert_plugin_names_to_filter_names works" {
+	assert_equals "foo" "$(echo "foo" | convert_plugin_names_to_filter_names)"
+	assert_equals "foo,bar" "$(echo "foo,bar" | convert_plugin_names_to_filter_names)"
+	assert_equals "foo,bar,baz" "$(echo "foo,     bar,      baz," | convert_plugin_names_to_filter_names)"
+	assert_equals "DIGEST-MD5" "$(echo "digestmd5" | convert_plugin_names_to_filter_names)"
+	assert_equals "CRAM-MD5" "$(echo "crammd5" | convert_plugin_names_to_filter_names)"
+	assert_equals "DIGEST-MD5,ntlm,CRAM-MD5,plain,login,anonymous" "$(echo "digestmd5,ntlm,crammd5,plain,login,anonymous" | convert_plugin_names_to_filter_names)"
+	assert_equals "DIGEST-MD5,ntlm,CRAM-MD5,plain,login,anonymous" "$(echo "DIGESTMD5,ntlm,CRAMMD5,plain,login,anonymous" | convert_plugin_names_to_filter_names)"
+
+}
+

unit-tests/Dockerfile

@@ -1,4 +1,5 @@
-ARG ALPINE_VERSION=latest
+# Changed this to specific alpine version so it doesn't get refreshed / pulled from Docker hub every time.
+ARG ALPINE_VERSION=3.19
 FROM alpine:${ALPINE_VERSION} as build
 
 ARG SASL_XOAUTH2_REPO_URL=https://github.com/tarickb/sasl-xoauth2.git