Merge pull request #760 from matrix-org/matthew/preview_url_ip_whitelist

add a url_preview_ip_range_whitelist config param

1 files changed, 16 insertions, 2 deletions

diff --git a/synapse/config/repository.py b/synapse/config/repository.py

index d61e525e62..8810079848 100644
--- a/synapse/config/repository.py
+++ b/synapse/config/repository.py
@@ -100,8 +100,13 @@ class ContentRepositoryConfig(Config):
                     "to work"
                 )
 
-            if "url_preview_url_blacklist" in config:
-                self.url_preview_url_blacklist = config["url_preview_url_blacklist"]
+            self.url_preview_ip_range_whitelist = IPSet(
+                config.get("url_preview_ip_range_whitelist", ())
+            )
+
+            self.url_preview_url_blacklist = config.get(
+                "url_preview_url_blacklist", ()
+            )
 
     def default_config(self, **kwargs):
         media_store = self.default_path("media_store")
@@ -162,6 +167,15 @@ class ContentRepositoryConfig(Config):
         # - '10.0.0.0/8'
         # - '172.16.0.0/12'
         # - '192.168.0.0/16'
+        #
+        # List of IP address CIDR ranges that the URL preview spider is allowed
+        # to access even if they are specified in url_preview_ip_range_blacklist.
+        # This is useful for specifying exceptions to wide-ranging blacklisted
+        # target IP ranges - e.g. for enabling URL previews for a specific private
+        # website only visible in your network.
+        #
+        # url_preview_ip_range_whitelist:
+        # - '192.168.1.1'
 
         # Optional list of URL matches that the URL preview spider is
         # denied from accessing.  You should use url_preview_ip_range_blacklist