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Merge commit 'a845abbf3' into matrix-org-hotfixes

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Richard van der Hoff 2019-05-03 17:12:28 +01:00
parent 7467738834 a845abbf3a
commit e7dcee13da
5 changed files with 42 additions and 17 deletions
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1
changelog.d/5133.bugfix Normal file
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@ -0,0 +1 @@
Switch to using a cryptographically-secure random number generator for token strings, ensuring they cannot be predicted by an attacker. Thanks to @opnsec for identifying and responsibly disclosing this issue!

1
changelog.d/5134.bugfix Normal file
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@ -0,0 +1 @@
Blacklist 0.0.0.0 and :: by default for URL previews. Thanks to @opnsec for identifying and responsibly disclosing this issue too!

17
docs/sample_config.yaml
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@ -548,11 +548,12 @@ uploads_path: "DATADIR/uploads"
# height: 600
# method: scale
# 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
@ -562,6 +563,12 @@ uploads_path: "DATADIR/uploads"
# synapse to issue arbitrary GET requests to your internal services,
# causing serious security issues.
#
# (0.0.0.0 and :: are always blacklisted, whether or not they are explicitly
# listed here, since they correspond to unroutable addresses.)
#
# This must be specified if url_preview_enabled is set. 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'
@ -572,7 +579,7 @@ uploads_path: "DATADIR/uploads"
# - '::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

31
synapse/config/repository.py
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@ -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 +279,12 @@ class ContentRepositoryConfig(Config):
# synapse to issue arbitrary GET requests to your internal services,
# causing serious security issues.
#
# (0.0.0.0 and :: are always blacklisted, whether or not they are explicitly
# listed here, since they correspond to unroutable addresses.)
#
# This must be specified if url_preview_enabled is set. 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 +295,7 @@ 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

9
synapse/util/stringutils.py
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@ -24,14 +24,19 @@ _string_with_symbols = (
string.digits + string.ascii_letters + ".,;:^&*-_+=#~@"
)
# random_string and random_string_with_symbols are used for a range of things,
# some cryptographically important, some less so. We use SystemRandom to make sure
# we get cryptographically-secure randoms.
rand = random.SystemRandom()
def random_string(length):
return ''.join(random.choice(string.ascii_letters) for _ in range(length))
return ''.join(rand.choice(string.ascii_letters) for _ in range(length))
def random_string_with_symbols(length):
return ''.join(
random.choice(_string_with_symbols) for _ in range(length)
rand.choice(_string_with_symbols) for _ in range(length)
)