From 2f48c4e1ae40869a1bc5dcb36557ad0a0d8a5728 Mon Sep 17 00:00:00 2001 From: Andrew Morgan <1342360+anoadragon453@users.noreply.github.com> Date: Fri, 10 May 2019 10:32:44 -0700 Subject: URL preview blacklisting fixes (#5155) Prevents a SynapseError being raised inside of a IResolutionReceiver and instead opts to just return 0 results. This thus means that we have to lump a failed lookup and a blacklisted lookup together with the same error message, but the substitute should be generic enough to cover both cases. --- synapse/rest/media/v1/preview_url_resource.py | 10 ++++++++++ 1 file changed, 10 insertions(+) (limited to 'synapse/rest/media/v1/preview_url_resource.py') diff --git a/synapse/rest/media/v1/preview_url_resource.py b/synapse/rest/media/v1/preview_url_resource.py index ba3ab1d37d..acf87709f2 100644 --- a/synapse/rest/media/v1/preview_url_resource.py +++ b/synapse/rest/media/v1/preview_url_resource.py @@ -31,6 +31,7 @@ from six.moves import urllib_parse as urlparse from canonicaljson import json from twisted.internet import defer +from twisted.internet.error import DNSLookupError from twisted.web.resource import Resource from twisted.web.server import NOT_DONE_YET @@ -328,9 +329,18 @@ class PreviewUrlResource(Resource): # handler will return a SynapseError to the client instead of # blank data or a 500. raise + except DNSLookupError: + # DNS lookup returned no results + # Note: This will also be the case if one of the resolved IP + # addresses is blacklisted + raise SynapseError( + 502, "DNS resolution failure during URL preview generation", + Codes.UNKNOWN + ) except Exception as e: # FIXME: pass through 404s and other error messages nicely logger.warn("Error downloading %s: %r", url, e) + raise SynapseError( 500, "Failed to download content: %s" % ( traceback.format_exception_only(sys.exc_info()[0], e), -- cgit 1.5.1