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authorAndrej Shadura <andrewsh@debian.org>2019-11-11 15:27:12 +0100
committerAndrej Shadura <andrewsh@debian.org>2019-11-11 15:27:12 +0100
commitc3e687e74cf69e8b60c663af1cd7a8817cbd1c82 (patch)
treee5587cacb2ad3e4364829d102b4a0b0f25b8bb5b
parent790aead4376316a1414bc48787cf84c2ee80e6f5 (diff)
New upstream version 1.5.1
-rw-r--r--CHANGES.md9
-rw-r--r--debian/changelog6
-rw-r--r--synapse/__init__.py2
-rw-r--r--synapse/rest/media/v1/preview_url_resource.py21
-rw-r--r--tests/rest/media/v1/test_url_preview.py35
5 files changed, 71 insertions, 2 deletions
diff --git a/CHANGES.md b/CHANGES.md
index 6faa4b8d..9312dc29 100644
--- a/CHANGES.md
+++ b/CHANGES.md
@@ -1,3 +1,12 @@
+Synapse 1.5.1 (2019-11-06)
+==========================
+
+Features
+--------
+
+- Limit the length of data returned by url previews, to prevent DoS attacks. ([\#6331](https://github.com/matrix-org/synapse/issues/6331), [\#6334](https://github.com/matrix-org/synapse/issues/6334))
+
+
Synapse 1.5.0 (2019-10-29)
==========================
diff --git a/debian/changelog b/debian/changelog
index acda7e5c..c4415f46 100644
--- a/debian/changelog
+++ b/debian/changelog
@@ -1,3 +1,9 @@
+matrix-synapse-py3 (1.5.1) stable; urgency=medium
+
+ * New synapse release 1.5.1.
+
+ -- Synapse Packaging team <packages@matrix.org> Wed, 06 Nov 2019 10:02:14 +0000
+
matrix-synapse-py3 (1.5.0) stable; urgency=medium
* New synapse release 1.5.0.
diff --git a/synapse/__init__.py b/synapse/__init__.py
index 8587ffa7..ec16f54a 100644
--- a/synapse/__init__.py
+++ b/synapse/__init__.py
@@ -36,7 +36,7 @@ try:
except ImportError:
pass
-__version__ = "1.5.0"
+__version__ = "1.5.1"
if bool(os.environ.get("SYNAPSE_TEST_PATCH_LOG_CONTEXTS", False)):
# We import here so that we don't have to install a bunch of deps when
diff --git a/synapse/rest/media/v1/preview_url_resource.py b/synapse/rest/media/v1/preview_url_resource.py
index 0c68c3aa..ec9c4619 100644
--- a/synapse/rest/media/v1/preview_url_resource.py
+++ b/synapse/rest/media/v1/preview_url_resource.py
@@ -56,6 +56,9 @@ logger = logging.getLogger(__name__)
_charset_match = re.compile(br"<\s*meta[^>]*charset\s*=\s*([a-z0-9-]+)", flags=re.I)
_content_type_match = re.compile(r'.*; *charset="?(.*?)"?(;|$)', flags=re.I)
+OG_TAG_NAME_MAXLEN = 50
+OG_TAG_VALUE_MAXLEN = 1000
+
class PreviewUrlResource(DirectServeResource):
isLeaf = True
@@ -167,7 +170,7 @@ class PreviewUrlResource(DirectServeResource):
ts (int):
Returns:
- Deferred[str]: json-encoded og data
+ Deferred[bytes]: json-encoded og data
"""
# check the URL cache in the DB (which will also provide us with
# historical previews, if we have any)
@@ -268,6 +271,18 @@ class PreviewUrlResource(DirectServeResource):
logger.warn("Failed to find any OG data in %s", url)
og = {}
+ # filter out any stupidly long values
+ keys_to_remove = []
+ for k, v in og.items():
+ # values can be numeric as well as strings, hence the cast to str
+ if len(k) > OG_TAG_NAME_MAXLEN or len(str(v)) > OG_TAG_VALUE_MAXLEN:
+ logger.warning(
+ "Pruning overlong tag %s from OG data", k[:OG_TAG_NAME_MAXLEN]
+ )
+ keys_to_remove.append(k)
+ for k in keys_to_remove:
+ del og[k]
+
logger.debug("Calculated OG for %s as %s" % (url, og))
jsonog = json.dumps(og)
@@ -502,6 +517,10 @@ def _calc_og(tree, media_uri):
og = {}
for tag in tree.xpath("//*/meta[starts-with(@property, 'og:')]"):
if "content" in tag.attrib:
+ # if we've got more than 50 tags, someone is taking the piss
+ if len(og) >= 50:
+ logger.warning("Skipping OG for page with too many 'og:' tags")
+ return {}
og[tag.attrib["property"]] = tag.attrib["content"]
# TODO: grab article: meta tags too, e.g.:
diff --git a/tests/rest/media/v1/test_url_preview.py b/tests/rest/media/v1/test_url_preview.py
index 976652ae..852b8ab1 100644
--- a/tests/rest/media/v1/test_url_preview.py
+++ b/tests/rest/media/v1/test_url_preview.py
@@ -247,6 +247,41 @@ class URLPreviewTests(unittest.HomeserverTestCase):
self.assertEqual(channel.code, 200)
self.assertEqual(channel.json_body["og:title"], "\u0434\u043a\u0430")
+ def test_overlong_title(self):
+ self.lookups["matrix.org"] = [(IPv4Address, "8.8.8.8")]
+
+ end_content = (
+ b"<html><head>"
+ b"<title>" + b"x" * 2000 + b"</title>"
+ b'<meta property="og:description" content="hi" />'
+ b"</head></html>"
+ )
+
+ request, channel = self.make_request(
+ "GET", "url_preview?url=http://matrix.org", shorthand=False
+ )
+ request.render(self.preview_url)
+ self.pump()
+
+ client = self.reactor.tcpClients[0][2].buildProtocol(None)
+ server = AccumulatingProtocol()
+ server.makeConnection(FakeTransport(client, self.reactor))
+ client.makeConnection(FakeTransport(server, self.reactor))
+ client.dataReceived(
+ (
+ b"HTTP/1.0 200 OK\r\nContent-Length: %d\r\n"
+ b'Content-Type: text/html; charset="windows-1251"\r\n\r\n'
+ )
+ % (len(end_content),)
+ + end_content
+ )
+
+ self.pump()
+ self.assertEqual(channel.code, 200)
+ res = channel.json_body
+ # We should only see the `og:description` field, as `title` is too long and should be stripped out
+ self.assertCountEqual(["og:description"], res.keys())
+
def test_ipaddr(self):
"""
IP addresses can be previewed directly.