Fix acme certificate generation

1 files changed, 110 insertions, 41 deletions

diff --git a/modules/private/certificates.nix b/modules/private/certificates.nix
index bbe4c3b..c568783 100644
--- a/modules/private/certificates.nix
+++ b/modules/private/certificates.nix
@@ -2,9 +2,13 @@
 {
   options.myServices.certificates = {
     enable = lib.mkEnableOption "enable certificates";
+    webroot = lib.mkOption {
+      readOnly = true;
+      default = "/var/lib/acme/acme-challenges";
+    };
     certConfig = lib.mkOption {
       default = {
-        webroot = "/var/lib/acme/acme-challenges";
+        webroot = lib.mkForce null; # avoids creation of tmpfiles
         email = "ismael@bouya.org";
         postRun = builtins.concatStringsSep "\n" [
           (lib.optionalString config.services.httpd.Prod.enable "systemctl reload httpdProd.service")
@@ -13,6 +17,7 @@
           (lib.optionalString config.services.nginx.enable "systemctl reload nginx.service")
         ];
         extraLegoRenewFlags = [ "--reuse-key" ];
+        keyType = lib.mkDefault "ec256"; # https://github.com/NixOS/nixpkgs/pull/83121
       };
       description = "Default configuration for certificates";
     };
@@ -20,13 +25,13 @@
 
   config = lib.mkIf config.myServices.certificates.enable {
     services.duplyBackup.profiles.system.excludeFile = ''
-      + /var/lib/acme/acme-challenges
+      + ${config.myServices.certificates.webroot}
       '';
     services.nginx = {
       recommendedTlsSettings = true;
       virtualHosts = {
         "${config.hostEnv.fqdn}" = {
-          acmeRoot = config.security.acme.certs."${name}".webroot;
+          acmeRoot = config.myServices.certificates.webroot;
           useACMEHost = name;
           forceSSL = true;
         };
@@ -45,6 +50,15 @@
       };
     };
 
+    users.users.acme = {
+      uid = config.ids.uids.acme;
+      group = "acme";
+      description = "Acme user";
+    };
+    users.groups.acme = {
+      gid = config.ids.gids.acme;
+    };
+
     systemd.services = lib.attrsets.mapAttrs' (k: v:
       lib.attrsets.nameValuePair "acme-selfsigned-${k}" {
           wantedBy = [ "acme-selfsigned-certificates.target" ];
@@ -62,50 +76,105 @@
     lib.attrsets.mapAttrs' (k: data:
       lib.attrsets.nameValuePair "acme-${k}" {
         after = lib.mkAfter [ "bind.service" ];
-        serviceConfig.ExecStartPre =
-          let
-            script = pkgs.writeScript "acme-pre-start" ''
-              #!${pkgs.runtimeShell} -e
-              mkdir -p '${data.webroot}/.well-known/acme-challenge'
-              chmod a+w '${data.webroot}/.well-known/acme-challenge'
-              #doesn't work for multiple concurrent runs
-              #chown -R '${data.user}:${data.group}' '${data.webroot}/.well-known/acme-challenge'
-            '';
-          in
-          "+${script}";
-        # This is a workaround to
-        # https://github.com/NixOS/nixpkgs/issues/84409
-        # https://github.com/NixOS/nixpkgs/issues/84633
-        serviceConfig.RemainAfterExit = lib.mkForce false;
-        serviceConfig.WorkingDirectory = lib.mkForce "/var/lib/acme/${k}/.lego";
-        serviceConfig.StateDirectory = lib.mkForce "acme/${k}/.lego acme/${k} acme/.lego/${k} acme/.lego/accounts";
-        serviceConfig.ExecStartPost =
+        serviceConfig =
           let
-            keyName = builtins.replaceStrings ["*"] ["_"] data.domain;
+            cfg = config.security.acme;
+            hashOptions = let
+              domains = builtins.concatStringsSep "," (
+                [ data.domain ] ++ (builtins.attrNames data.extraDomains)
+              );
+              certOptions = builtins.concatStringsSep "," [
+                (if data.ocspMustStaple then "must-staple" else "no-must-staple")
+              ];
+            in
+              builtins.hashString "sha256" (builtins.concatStringsSep ";" [ data.keyType domains certOptions ]);
+            accountsDir = "accounts-${data.keyType}";
+            lpath = "acme/${k}";
+            apath = "/var/lib/${lpath}";
+            spath = "/var/lib/acme/.lego/${k}";
             fileMode = if data.allowKeysForGroup then "640" else "600";
-            spath = "/var/lib/acme/${k}/.lego";
-            script = pkgs.writeScript "acme-post-start" ''
+            dirFileMode = if data.allowKeysForGroup then "750" else "700";
+            globalOpts = [ "-d" data.domain "--email" data.email "--path" "." "--key-type" data.keyType ]
+              ++ lib.optionals (cfg.acceptTerms) [ "--accept-tos" ]
+              ++ lib.optionals (data.dnsProvider != null && !data.dnsPropagationCheck) [ "--dns.disable-cp" ]
+              ++ lib.concatLists (lib.mapAttrsToList (name: root: [ "-d" name ]) data.extraDomains)
+              ++ (if data.dnsProvider != null then [ "--dns" data.dnsProvider ] else [ "--http" "--http.webroot" config.myServices.certificates.webroot ])
+              ++ lib.optionals (cfg.server != null || data.server != null) ["--server" (if data.server == null then cfg.server else data.server)];
+            certOpts = lib.optionals data.ocspMustStaple [ "--must-staple" ];
+            runOpts = lib.escapeShellArgs (globalOpts ++ [ "run" ] ++ certOpts);
+            renewOpts = lib.escapeShellArgs (globalOpts ++
+              [ "renew" "--days" (builtins.toString cfg.validMinDays) ] ++
+              certOpts ++ data.extraLegoRenewFlags);
+            forceRenewOpts = lib.escapeShellArgs (globalOpts ++
+              [ "renew" "--days" "999" ] ++
+              certOpts ++ data.extraLegoRenewFlags);
+            keyName = builtins.replaceStrings ["*"] ["_"] data.domain;
+          in {
+            User = lib.mkForce "acme";
+            Group = lib.mkForce "acme";
+            WorkingDirectory = lib.mkForce spath;
+            StateDirectory = lib.mkForce "acme/.lego/${k} acme/.lego/${accountsDir}";
+            ExecStartPre =
+              let
+                script = pkgs.writeScript "acme-prestart" ''
+                  #!${pkgs.runtimeShell} -e
+                  install -m 0755 -o acme -g acme -d ${config.myServices.certificates.webroot}
+                '';
+              in
+                lib.mkForce "+${script}";
+            ExecStart = lib.mkForce (pkgs.writeScript "acme-start" ''
               #!${pkgs.runtimeShell} -e
-              cd /var/lib/acme/${k}
-
-              # Test that existing cert is older than new cert
-              KEY=${spath}/certificates/${keyName}.key
-              if [ -e $KEY -a $KEY -nt key.pem ]; then
-                cp -p ${spath}/certificates/${keyName}.key key.pem
-                cp -p ${spath}/certificates/${keyName}.crt fullchain.pem
-                cp -p ${spath}/certificates/${keyName}.issuer.crt chain.pem
-                ln -sf fullchain.pem cert.pem
-                cat key.pem fullchain.pem > full.pem
-
-                ${data.postRun}
+              # lego doesn't check key type after initial creation, we
+              # need to check for him
+              if [ -L ${spath}/accounts -o -d ${spath}/accounts ]; then
+                if [ -L ${spath}/accounts -a "$(readlink ${spath}/accounts)" != ../${accountsDir} ]; then
+                  ln -sfn ../${accountsDir} ${spath}/accounts
+                  mv -f ${spath}/certificates/${keyName}.key ${spath}/certificates/${keyName}.key.old
+                fi
+              else
+                ln -s ../${accountsDir} ${spath}/accounts
+              fi
+              # check if domain changed: lego doesn't check by itself
+              if [ ! -e ${spath}/certificates/${keyName}.crt -o ! -e ${spath}/certificates/${keyName}.key -o ! -e "${spath}/accounts/acme-v02.api.letsencrypt.org/${data.email}/account.json" ]; then
+                ${pkgs.lego}/bin/lego ${runOpts}
+              elif [ ! -f ${spath}/currentDomains -o "$(cat ${spath}/currentDomains)" != "${hashOptions}" ]; then
+                ${pkgs.lego}/bin/lego ${forceRenewOpts}
+              else
+                ${pkgs.lego}/bin/lego ${renewOpts}
               fi
+            '');
+            ExecStartPost =
+              let
+                script = pkgs.writeScript "acme-post-start" ''
+                  #!${pkgs.runtimeShell} -e
+                  install -m 0755 -o root -g root -d /var/lib/acme
+                  install -m 0${dirFileMode} -o ${data.user} -g ${data.group} -d /var/lib/acme/${k}
+                  cd /var/lib/acme/${k}
+
+                  # Test that existing cert is older than new cert
+                  KEY=${spath}/certificates/${keyName}.key
+                  KEY_CHANGED=no
+                  if [ -e $KEY -a $KEY -nt key.pem ]; then
+                    KEY_CHANGED=yes
+                    cp -p ${spath}/certificates/${keyName}.key key.pem
+                    cp -p ${spath}/certificates/${keyName}.crt fullchain.pem
+                    cp -p ${spath}/certificates/${keyName}.issuer.crt chain.pem
+                    ln -sf fullchain.pem cert.pem
+                    cat key.pem fullchain.pem > full.pem
+                    echo -n "${hashOptions}" > ${spath}/currentDomains
+                  fi
 
-              chmod ${fileMode} *.pem
-              chown '${data.user}:${data.group}' *.pem
-            '';
-          in
-            lib.mkForce "+${script}";
+                  chmod ${fileMode} *.pem
+                  chown '${data.user}:${data.group}' *.pem
 
+                  if [ "$KEY_CHANGED" = "yes" ]; then
+                    : # noop in case postRun is empty
+                    ${data.postRun}
+                  fi
+                '';
+              in
+                lib.mkForce "+${script}";
+          };
       }
     ) config.security.acme.certs //
     {