Add warnings to ip_range_blacklist usage with proxies (#10129)

Per issue #9812 using `url_preview_ip_range_blacklist` with a proxy via `HTTPS_PROXY` or `HTTP_PROXY` environment variables has some inconsistent bahavior than mentioned. This PR changes the following:

- Changes the Sample Config file to include a note mentioning that `url_preview_ip_range_blacklist` and `ip_range_blacklist` is ignored when using a proxy
- Changes some logic in synapse/config/repository.py to send a warning when both `*ip_range_blacklist` configs and a proxy environment variable are set and but no longer throws an error.

Signed-off-by: Kento Okamoto <kentokamoto@protonmail.com>
This commit is contained in:
Kento Okamoto 2021-08-03 11:13:34 -07:00 committed by GitHub
parent 951648f26a
commit 72935b7c50
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4 changed files with 26 additions and 5 deletions

1
changelog.d/10129.bugfix Normal file
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@ -0,0 +1 @@
Add some clarification to the sample config file. Contributed by @Kentokamoto.

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@ -210,6 +210,8 @@ presence:
#
# This option replaces federation_ip_range_blacklist in Synapse v1.25.0.
#
# Note: The value is ignored when an HTTP proxy is in use
#
#ip_range_blacklist:
# - '127.0.0.0/8'
# - '10.0.0.0/8'
@ -972,6 +974,8 @@ media_store_path: "DATADIR/media_store"
# This must be specified if url_preview_enabled is set. It is recommended that
# you uncomment the following list as a starting point.
#
# Note: The value is ignored when an HTTP proxy is in use
#
#url_preview_ip_range_blacklist:
# - '127.0.0.0/8'
# - '10.0.0.0/8'

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@ -12,9 +12,11 @@
# See the License for the specific language governing permissions and
# limitations under the License.
import logging
import os
from collections import namedtuple
from typing import Dict, List
from urllib.request import getproxies_environment # type: ignore
from synapse.config.server import DEFAULT_IP_RANGE_BLACKLIST, generate_ip_set
from synapse.python_dependencies import DependencyException, check_requirements
@ -22,6 +24,8 @@ from synapse.util.module_loader import load_module
from ._base import Config, ConfigError
logger = logging.getLogger(__name__)
DEFAULT_THUMBNAIL_SIZES = [
{"width": 32, "height": 32, "method": "crop"},
{"width": 96, "height": 96, "method": "crop"},
@ -36,6 +40,9 @@ THUMBNAIL_SIZE_YAML = """\
# method: %(method)s
"""
HTTP_PROXY_SET_WARNING = """\
The Synapse config url_preview_ip_range_blacklist will be ignored as an HTTP(s) proxy is configured."""
ThumbnailRequirement = namedtuple(
"ThumbnailRequirement", ["width", "height", "method", "media_type"]
)
@ -180,12 +187,17 @@ class ContentRepositoryConfig(Config):
e.message # noqa: B306, DependencyException.message is a property
)
proxy_env = getproxies_environment()
if "url_preview_ip_range_blacklist" not in config:
if "http" not in proxy_env or "https" not in proxy_env:
raise ConfigError(
"For security, you must specify an explicit target IP address "
"blacklist in url_preview_ip_range_blacklist for url previewing "
"to work"
)
else:
if "http" in proxy_env or "https" in proxy_env:
logger.warning("".join(HTTP_PROXY_SET_WARNING))
# we always blacklist '0.0.0.0' and '::', which are supposed to be
# unroutable addresses.
@ -292,6 +304,8 @@ class ContentRepositoryConfig(Config):
# This must be specified if url_preview_enabled is set. It is recommended that
# you uncomment the following list as a starting point.
#
# Note: The value is ignored when an HTTP proxy is in use
#
#url_preview_ip_range_blacklist:
%(ip_range_blacklist)s

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@ -960,6 +960,8 @@ class ServerConfig(Config):
#
# This option replaces federation_ip_range_blacklist in Synapse v1.25.0.
#
# Note: The value is ignored when an HTTP proxy is in use
#
#ip_range_blacklist:
%(ip_range_blacklist)s