DKIM: also include the "d=" tag in key filenames, not only the "s=" tag.

While the combination of "s=" tag (selector) & "d=" tag signing domain
maps to a unique key, the selector alone doesn't necessarily.

7 files changed, 13 insertions, 24 deletions

diff --git a/certs/dkim/8f00fb94ec6c37aacb48bd43e073f9b7.pub b/certs/dkim/8f00fb94ec6c37aacb48bd43e073f9b7:fripost.org.pub
index ef400f4..ef400f4 100644
--- a/certs/dkim/8f00fb94ec6c37aacb48bd43e073f9b7.pub
+++ b/certs/dkim/8f00fb94ec6c37aacb48bd43e073f9b7:fripost.org.pub
diff --git a/certs/dkim/9df9cdc7e101629b5003b587945afa70.pub b/certs/dkim/9df9cdc7e101629b5003b587945afa70:x.fripost.org.pub
index 2574f71..2574f71 100644
--- a/certs/dkim/9df9cdc7e101629b5003b587945afa70.pub
+++ b/certs/dkim/9df9cdc7e101629b5003b587945afa70:x.fripost.org.pub
diff --git a/certs/dkim/README b/certs/dkim/README
index e5addf9..2137a8d 100644
--- a/certs/dkim/README
+++ b/certs/dkim/README
@@ -1,10 +1,11 @@
-To convert a PEM-encoded public key to a TXT record, run
+To convert the PEM-encoded public keys from this directory to TXT
+records, run
 
     $ SELECTOR="8f00fb94ec6c37aacb48bd43e073f9b7"
     $ DOMAIN="fripost.org"
-    $ printf "%s._domainkey%s    IN TXT    (\n" "$SELECTOR" "${DOMAIN:+.$DOMAIN.}"; \
+    $ printf "%s._domainkey.%s    IN TXT    (\n" "$SELECTOR" "$DOMAIN"; \
       { printf "v=DKIM1; k=rsa; t=s; s=email; p=";
-        sed '/^--.*--$/d' <"./certs/dkim/$SELECTOR.pub" | tr -d '\n';
+        openssl pkey -pubin -in "./certs/dkim/$SELECTOR:$DOMAIN.pub" -outform DER | base64 -w0
       } | fold -w64 | sed 's/.*/    "&"/; $s/$/ )\n/'
 
 Remove the "t=s" tag if subdomaining or third-party signature (hosted
diff --git a/group_vars/all.yml b/group_vars/all.yml
index f222b56..4fcfc39 100644
--- a/group_vars/all.yml
+++ b/group_vars/all.yml
@@ -53,7 +53,7 @@ dkim_keys:
     "fripost.org":
       # domain of the entity signing the message (should be unique accross match keys)
       d: fripost.org
-      # selector (should be globally unique and random)
+      # selector (randomly generated with `xxd -p -l16 </dev/urandom`)
       s: 8f00fb94ec6c37aacb48bd43e073f9b7
     "~": # catch-all, for our virtual domains
       d: x.fripost.org
diff --git a/roles/amavis/tasks/main.yml b/roles/amavis/tasks/main.yml
index 92a0e81..3036c52 100644
--- a/roles/amavis/tasks/main.yml
+++ b/roles/amavis/tasks/main.yml
@@ -52,8 +52,8 @@
     - dkim
 
 - name: Generate a private key for DKIM signing
-  command: genkeypair.sh dkim --privkey=/etc/amavis/dkim/{{ item }}.pem -t rsa -b 2048
-  with_items: "{{ (dkim_keys[inventory_hostname_short] | default({})).values() | map(attribute='s') | list }}"
+  command: genkeypair.sh dkim --privkey="/etc/amavis/dkim/{{ item.s }}:{{ item.d }}.pem" -t rsa -b 2048
+  with_items: "{{ (dkim_keys[inventory_hostname_short] | default({})).values() | list }}"
   register: dkim
   changed_when: dkim.rc == 0
   failed_when: dkim.rc > 1
@@ -66,9 +66,9 @@
 
 - name: Fetch DKIM keys
   fetch_cmd: cmd="openssl pkey -pubout -outform PEM"
-             stdin=/etc/amavis/dkim/{{ item }}.pem
-             dest=certs/dkim/{{ item }}.pub
-  with_items: "{{ (dkim_keys[inventory_hostname_short] | default({})).values() | map(attribute='s') | list }}"
+             stdin="/etc/amavis/dkim/{{ item.s }}:{{ item.d }}.pem"
+             dest="certs/dkim/{{ item.s }}:{{ item.d }}.pub"
+  with_items: "{{ (dkim_keys[inventory_hostname_short] | default({})).values() | list }}"
   tags:
     - genkey
     - dkim
diff --git a/roles/amavis/templates/etc/amavis/conf.d/50-user.j2 b/roles/amavis/templates/etc/amavis/conf.d/50-user.j2
index f3ff416..a09c366 100644
--- a/roles/amavis/templates/etc/amavis/conf.d/50-user.j2
+++ b/roles/amavis/templates/etc/amavis/conf.d/50-user.j2
@@ -33,7 +33,7 @@ $enable_dkim_signing = 1;
 # Sign *all* outgoing mails with *our* key (yes, amavis complains, but this is
 # safe as we force our domain with the 'd' tag).
 {% for x,k in dkim_keys[inventory_hostname_short] | default({}) | dictsort() -%}
-dkim_key({{ (x == "~") | ternary('qr/./', "'"+x+"'") }}, '{{ k.s }}', '/etc/amavis/dkim/{{ k.s }}.pem');
+dkim_key({{ (x == "~") | ternary('qr/./', "'"+x+"'") }}, '{{ k.s }}', '/etc/amavis/dkim/{{ k.s }}:{{ k.d }}.pem');
 {% endfor -%}
 @dkim_signature_options_bysender_maps = (
 {% for x,k in dkim_keys[inventory_hostname_short] | default({}) | dictsort() %}
diff --git a/roles/common/files/usr/local/bin/genkeypair.sh b/roles/common/files/usr/local/bin/genkeypair.sh
index 01b279a..ad65aef 100755
--- a/roles/common/files/usr/local/bin/genkeypair.sh
+++ b/roles/common/files/usr/local/bin/genkeypair.sh
@@ -21,6 +21,7 @@
 
 set -ue
 PATH=/usr/bin:/bin
+export PATH
 
 # Default values
 type=rsa
@@ -74,18 +75,6 @@ usage() {
 	EOF
 }
 
-dkiminfo() {
-    echo "Add the following TXT record to your DNS zone:"
-    echo "${cn:-$(date +%Y%m%d)}._domainkey\tIN\tTXT ( "
-    # See https://tools.ietf.org/html/rfc4871#section-3.6.1
-    # t=s:      the "i=" domain in signature headers MUST NOT be a subdomain of "d="
-    # s=email:  limit DKIM signing to email
-    openssl pkey -pubout <"$privkey" | sed '/^--.*--$/d' \
-    | { echo -n "v=DKIM1; k=$type; t=s; s=email; p="; tr -d '\n'; } \
-    | fold -w 250 \
-    | { sed 's/.*/\t"&"/'; echo ' )'; }
-}
-
 [ $# -gt 0 ] || { usage; exit 2; }
 cmd="$1"; shift
 case "$cmd" in
@@ -181,12 +170,11 @@ fi
 
 if [ -s "$privkey" -a $force -eq 0 ]; then
     echo "Error: private key exists: $privkey" >&2
-    [ "$cmd" = dkim ] && dkiminfo
     exit 1
 elif [ ! -s "$privkey" -o $force -ge 2 ]; then
     install --mode="${mode:-0600}" ${owner:+--owner="$owner"} ${group:+--group="$group"} /dev/null "$privkey" || exit 2
     openssl $genkey -rand /dev/urandom $genkeyargs >"$privkey" || exit 2
-    [ "$cmd" = dkim ] && { dkiminfo; exit; }
+    [ "$cmd" = dkim ] && exit
 fi
 
 if [ "$cmd" = x509 -a "$pubkey" = "$privkey" ]; then