[__opendkim*] FreeBSD support and minor fixes

While adding FreeBSD support to the type I noticed various issues:

- We were making sure that the KeyTable and SigningTable were created in
  __opendkim_genkey, but that was being done with the default cdist permissions
  (0400) which could result in issues when reloading the service after privilege
  drop.
  This is addressed by checking that it exists/creating it in __opendkim (just
  once, not once per __opendkim_genkey call) with laxer permissions (0444).
- In __opendkim, the service was being started after the config file was
  installed. This is insufficient as OpenDKIM will refuse to start with the
  generated config if either SigningTable or KeyTable do not exist yet.
- __opendkim_genkey had the implicit assumption that the --directory parameter
  always ended in a slash. This was not documented and error-prone; we are now
  a bit laxer and add the trailing slash if it is missing.
- __opendkim_genkey was not changing permissions for the resulting .txt file.
  This was not critical for it to function, but it was inconsistent.
- As documented in #17, __opendkim allows for a --userid parameter that might
  cause issues with keys generated by __opendkim_genkey.
  This issue has not been addressed yet, but I recommend deprecating the
  --userid parameter.

type/__opendkim/files/opendkim.conf.sh

@@ -1,6 +1,7 @@
 #!/bin/sh -e
 # Generate an opendkim.conf(5) file for opendkim(8).
 
+echo "# Managed remotely, manual changes will be lost."
 
 # Optional chdir(2)
 if [ "$BASEDIR" ];
@@ -33,8 +34,8 @@ then
 fi
 
 # Key and Domain tables
-echo 'KeyTable /etc/opendkim/KeyTable'
+echo "KeyTable ${CFG_DIR}/KeyTable"
-echo 'SigningTable /etc/opendkim/SigningTable'
+echo "SigningTable ${CFG_DIR}/SigningTable"
 
 # Required socket to listen on
 printf "Socket %s\n" "${SOCKET:?}"

type/__opendkim/man.rst

@@ -14,8 +14,8 @@ installation and basic configuration of an instance of OpenDKIM.
 Note that this type does not generate or ensure that a key is present: use
 `cdist-type__opendkim-genkey(7)` for that.
 
-Note that this type is currently only implemented for Alpine Linux. Please
+Note that this type is currently only implemented for Alpine Linux and FreeBSD.
-contribute an implementation if you can.
+Please contribute an implementation if you can.
 
 
 REQUIRED PARAMETERS
@@ -42,8 +42,9 @@ umask
   Set the umask for the socket and PID file.
 
 userid
-  Change the user the opendkim program is to run as. By default, Alpine Linux's
+  Change the user the opendkim program is to run as.
-  OpenRC service will set this to `opendkim` on the command-line.
+  By default, Alpine Linux's OpenRC service will set this to `opendkim` on the
+  command-line and FreeBSD's rc will set it to `mailnull`.
 
 custom-config
   The string following this parameter is appended as-is in the configuration, to
@@ -86,11 +87,12 @@ SEE ALSO
 AUTHORS
 -------
 Joachim Desroches <joachim.desroches@epfl.ch>
+Evilham <contact@evilham.com>
 
 
 COPYING
 -------
-Copyright \(C) 2021 Joachim Desroches. You can redistribute it
+Copyright \(C) 2022 Joachim Desroches, Evilham. You can redistribute it
 and/or modify it under the terms of the GNU General Public License as
 published by the Free Software Foundation, either version 3 of the
 License, or (at your option) any later version.

type/__opendkim/manifest

@@ -20,16 +20,23 @@
 
 os=$(cat "${__global:?}/explorer/os")
 
+CFG_DIR="/etc/opendkim"
+service="opendkim"
 case "$os" in
 'alpine')
 	:
 	;;
+'freebsd')
+	CFG_DIR="/usr/local/etc/mail"
+	service="milter-opendkim"
+	;;
 *)
 	printf "__opendkim does not yet support %s.\n" "$os" >&2
 	printf "Please contribute an implementation if you can.\n" >&2
 	exit 1
 	;;
 esac
+export CFG_DIR
 
 __package opendkim
 
@@ -68,7 +75,7 @@ fi
 
 # Generate and deploy configuration file.
 source_file="${__object:?}/files/opendkim.conf"
-target_file="/etc/opendkim/opendkim.conf"
+target_file="${CFG_DIR}/opendkim.conf"
 
 mkdir -p "${__object:?}/files"
 
@@ -83,9 +90,22 @@ fi
 require="__package/opendkim" __file "$target_file" \
 	--source "$source_file" --mode 0644
 
-require="__package/opendkim" __start_on_boot opendkim
+require="__package/opendkim" __start_on_boot "${service}"
 
-require="__file${target_file}" \
+# Ensure Key and Signing tables exist and have proper permissions
+key_table="${CFG_DIR}/KeyTable"
+signing_table="${CFG_DIR}/SigningTable"
+
+require="__package/opendkim" \
+	__file "${key_table}" \
+	--mode 444
+
+require="__package/opendkim" \
+	__file "${signing_table}" \
+	--mode 444
+
+require="__file${target_file} __file${key_table}
+		__file${signing_table} __start_on_boot/${service}" \
 	__check_messages opendkim \
 		--pattern "^__file${target_file}" \
-		--execute "service opendkim restart"
+		--execute "service ${service} restart"

type/__opendkim_genkey/gencode-remote

@@ -30,7 +30,8 @@ fi
 
 DIRECTORY="/var/db/dkim/"
 if [ -f "${__object:?}/parameter/directory" ]; then
-	DIRECTORY="$(cat "${__object:?}/parameter/directory")"
+	# Be forgiving about a lack of trailing slash
+	DIRECTORY="$(sed -E 's!([^/])$!\1/!' < "${__object:?}/parameter/directory")"
 fi
 
 # Boolean parameters
@@ -44,7 +45,12 @@ if [ -f "${__object:?}/parameters/unrestricted" ]; then
 	RESTRICTED=
 fi
 
+user="$(cat "${__object:?}/user")"
+group="$(cat "${__object:?}/group")"
+
 if ! [ -f "${DIRECTORY}${SELECTOR}.private" ]; then
 	echo "opendkim-genkey $BITS --domain=$DOMAIN --directory=$DIRECTORY $RESTRICTED --selector=$SELECTOR $SUBDOMAINS"
-	echo "chown opendkim:opendkim ${DIRECTORY}${SELECTOR}.private"
+	echo "chown ${user}:${group} ${DIRECTORY}${SELECTOR}.private"
+	# This is usually generated, if it weren't we do not want to fail
+	echo "chown ${user}:${group} ${DIRECTORY}${SELECTOR}.txt || true"
 fi

type/__opendkim_genkey/man.rst

@@ -17,8 +17,8 @@ will be added to the OpenDKIM signing table, using either the domain or the
 provided key for the `domain:selector:keyfile` value in the table. An existing
 key will not be overwritten.
 
-Currently, this type is only implemented for Alpine Linux. Please contribute an
+Currently, this type is only implemented for Alpine Linux and FreeBSD.
-implementation if you can.
+Please contribute an implementation if you can.
 
 REQUIRED PARAMETERS
 -------------------
@@ -85,11 +85,12 @@ SEE ALSO
 AUTHORS
 -------
 Joachim Desroches <joachim.desroches@epfl.ch>
+Evilham <contact@evilham.com>
 
 
 COPYING
 -------
-Copyright \(C) 2021 Joachim Desroches. You can redistribute it
+Copyright \(C) 2022 Joachim Desroches, Evilham. You can redistribute it
 and/or modify it under the terms of the GNU General Public License as
 published by the Free Software Foundation, either version 3 of the
 License, or (at your option) any later version.

type/__opendkim_genkey/manifest

@@ -21,10 +21,18 @@
 
 os=$(cat "${__global:?}/explorer/os")
 
+CFG_DIR="/etc/opendkim"
+user="opendkim"
+group="opendkim"
 case "$os" in
 'alpine')
 	:
 ;;
+'freebsd')
+	CFG_DIR="/usr/local/etc/mail"
+	user="mailnull"
+	group="mailnull"
+;;
 *)
 	cat <<- EOF >&2
 	__opendkim_genkey currently only supports Alpine Linux. Please
@@ -32,6 +40,9 @@ case "$os" in
 	EOF
 ;;
 esac
+# Persist user and group for gencode-remote
+printf '%s' "${user}" > "${__object:?}/user"
+printf '%s' "${group}" > "${__object:?}/group"
 
 SELECTOR="$(cat "${__object:?}/parameter/selector")"
 DOMAIN="$(cat "${__object:?}/parameter/domain")"
@@ -39,7 +50,8 @@ DOMAIN="$(cat "${__object:?}/parameter/domain")"
 DIRECTORY="/var/db/dkim/"
 if [ -f "${__object:?}/parameter/directory" ];
 then
-	DIRECTORY="$(cat "${__object:?}/parameter/directory")"
+	# Be forgiving about a lack of trailing slash
+	DIRECTORY="$(sed -E 's!([^/])$!\1/!' < "${__object:?}/parameter/directory")"
 fi
 
 SIGKEY="${DOMAIN:?}"
@@ -48,19 +60,26 @@ then
 	SIGKEY="$(cat "${__object:?}/parameter/sigkey")"
 fi
 
+# Ensure the key-container directory exists with the proper permissions
+__directory "${DIRECTORY}" \
+	--mode 0750 \
+	--owner "${user}" --group "${group}"
+
+# OS-specific code
+case "$os" in
+'alpine')
+	# This is needed for opendkim-genkey
 	__package opendkim-utils
+;;
+esac
 
-require='__package/opendkim-utils' \
+key_table="${CFG_DIR}/KeyTable"
-	__file /etc/opendkim/KeyTable
+signing_table="${CFG_DIR}/SigningTable"
-require='__package/opendkim-utils' \
-	__file /etc/opendkim/SigningTable
 
-require='__file/etc/opendkim/KeyTable' \
 __line "line-key-${__object_id:?}" \
-		--file /etc/opendkim/KeyTable \
+	--file "${key_table}" \
 	--line "${SELECTOR:?}._domainkey.${DOMAIN:?} ${DOMAIN:?}:${SELECTOR:?}:${DIRECTORY:?}${SELECTOR:?}.private"
 
-require='__file/etc/opendkim/SigningTable' \
 __line "line-sig-${__object_id:?}" \
-		--file /etc/opendkim/SigningTable \
+	--file "${signing_table}" \
 	--line "${SIGKEY:?} ${SELECTOR:?}._domainkey.${DOMAIN:?}"