servo: sftpgo: allow fully-anonymous www read access to /pub

this will help me write automated tests for its availability

hosts/by-name/servo/services/export/default.nix

@@ -12,6 +12,10 @@
     device = "/var/media";
     options = [ "rbind" ];
   };
+  fileSystems."/var/export/pub" = {
+    device = "/var/www/sites/uninsane.org/share";
+    options = [ "rbind" ];
+  };
   # fileSystems."/var/export/playground" = {
   #   device = config.fileSystems."/mnt/persist/ext".device;
   #   fsType = "btrfs";
@@ -37,7 +41,8 @@
     wantedBy = [ "nfs.service" "sftpgo.service" ];
     file.text = ''
       - media/         read-only:  Videos, Music, Books, etc
-      - playground/    read-write: use it to share files with other users of this server
+      - playground/    read-write: use it to share files with other users of this server, inaccessible from the www
+      - pub/           read-only:  content made to be shared with the www
     '';
   };
 

hosts/by-name/servo/services/export/sftpgo/default.nix

@@ -103,6 +103,13 @@ in
             debug = true;
             tls_mode = 2;  # 2 = "implicit FTPS": client negotiates TLS before any FTP command.
           }
+          {
+            # binding this means any doof client can connect (TLS only)
+            address = config.sane.netns.doof.hostVethIpv4;
+            port = 990;
+            debug = true;
+            tls_mode = 2;  # 2 = "implicit FTPS": client negotiates TLS before any FTP command.
+          }
         ];
 
         # active mode is susceptible to "bounce attacks", without much benefit over passive mode
@@ -119,7 +126,7 @@ in
         banner = ''
           Welcome, friends, to Colin's FTP server! Also available via NFS on the same host, but LAN-only.
 
-          Read-only access (LAN-restricted):
+          Read-only access (LAN clients see everything; WAN clients can only see /pub):
           Username: "anonymous"
           Password: "anonymous"
 

hosts/by-name/servo/services/export/sftpgo/external_auth_hook

@@ -45,6 +45,8 @@ from hmac import compare_digest
 
 authFail = dict(username="")
 
+PERM_DENY = []
+PERM_LIST = [ "list" ]
 PERM_RO = [ "list", "download" ]
 PERM_RW = [
   # read-only:
@@ -127,12 +129,14 @@ def getAuthResponse(ip: str, username: str, password: str) -> dict:
     return mkAuthOk(username, permissions = {
       "/": PERM_RW,
       "/playground": PERM_RW,
+      "/pub": PERM_RO,
     })
   if isWireguard(ip):
     # allow any user from wireguard
     return mkAuthOk(username, permissions = {
       "/": PERM_RW,
       "/playground": PERM_RW,
+      "/pub": PERM_RO,
     })
   if isLan(ip):
     if username == "anonymous":
@@ -140,7 +144,18 @@ def getAuthResponse(ip: str, username: str, password: str) -> dict:
       return mkAuthOk("anonymous", permissions = {
         "/": PERM_RO,
         "/playground": PERM_RW,
+        "/pub": PERM_RO,
       })
+  if username == "anonymous":
+    # anonymous users from the www can have even more limited access.
+    # mostly because i need an easy way to test WAN connectivity :-)
+    return mkAuthOk("anonymous", permissions = {
+      # "/": PERM_DENY,
+      "/": PERM_LIST,  #< REQUIRED, even for lftp to list a subdir
+      "/media": PERM_DENY,
+      "/playground": PERM_DENY,
+      "/pub": PERM_RO,
+    })
 
   return authFail