From 1a7104fde3abc5392b90ca084efa896d46e24f91 Mon Sep 17 00:00:00 2001 From: Richard van der Hoff Date: Fri, 3 May 2019 13:46:50 +0100 Subject: Blacklist 0.0.0.0 and :: by default for URL previews --- synapse/config/repository.py | 28 ++++++++++++++++++---------- 1 file changed, 18 insertions(+), 10 deletions(-) (limited to 'synapse/config') diff --git a/synapse/config/repository.py b/synapse/config/repository.py index 3f34ad9b2a..d155d69d8a 100644 --- a/synapse/config/repository.py +++ b/synapse/config/repository.py @@ -186,17 +186,21 @@ class ContentRepositoryConfig(Config): except ImportError: raise ConfigError(MISSING_NETADDR) - if "url_preview_ip_range_blacklist" in config: - self.url_preview_ip_range_blacklist = IPSet( - config["url_preview_ip_range_blacklist"] - ) - else: + if "url_preview_ip_range_blacklist" not in config: raise ConfigError( "For security, you must specify an explicit target IP address " "blacklist in url_preview_ip_range_blacklist for url previewing " "to work" ) + self.url_preview_ip_range_blacklist = IPSet( + config["url_preview_ip_range_blacklist"] + ) + + # we always blacklist '0.0.0.0' and '::', which are supposed to be + # unroutable addresses. + self.url_preview_ip_range_blacklist.update(['0.0.0.0', '::']) + self.url_preview_ip_range_whitelist = IPSet( config.get("url_preview_ip_range_whitelist", ()) ) @@ -260,11 +264,12 @@ class ContentRepositoryConfig(Config): #thumbnail_sizes: %(formatted_thumbnail_sizes)s - # Is the preview URL API enabled? If enabled, you *must* specify - # an explicit url_preview_ip_range_blacklist of IPs that the spider is - # denied from accessing. + # Is the preview URL API enabled? # - #url_preview_enabled: false + # 'false' by default: uncomment the following to enable it (and specify a + # url_preview_ip_range_blacklist blacklist). + # + #url_preview_enabled: true # List of IP address CIDR ranges that the URL preview spider is denied # from accessing. There are no defaults: you must explicitly @@ -274,6 +279,9 @@ class ContentRepositoryConfig(Config): # synapse to issue arbitrary GET requests to your internal services, # causing serious security issues. # + # This must be specified if url_preview_enabled. It is recommended that you + # uncomment the following list as a starting point. + # #url_preview_ip_range_blacklist: # - '127.0.0.0/8' # - '10.0.0.0/8' @@ -284,7 +292,7 @@ class ContentRepositoryConfig(Config): # - '::1/128' # - 'fe80::/64' # - 'fc00::/7' - # + # 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 -- cgit 1.4.1