2018-10-22 07:00:50 +00:00
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# frozen_string_literal: true
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2017-03-15 20:09:08 +00:00
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require 'resolv'
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2018-11-26 08:45:38 +00:00
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require 'ipaddress'
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2017-03-15 20:09:08 +00:00
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module Gitlab
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class UrlBlocker
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2018-03-28 17:27:16 +00:00
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BlockedUrlError = Class.new(StandardError)
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2017-03-18 17:56:05 +00:00
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2018-03-28 17:27:16 +00:00
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class << self
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2019-04-21 10:03:26 +00:00
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# Validates the given url according to the constraints specified by arguments.
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#
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# ports - Raises error if the given URL port does is not between given ports.
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# allow_localhost - Raises error if URL resolves to a localhost IP address and argument is true.
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# allow_local_network - Raises error if URL resolves to a link-local address and argument is true.
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# ascii_only - Raises error if URL has unicode characters and argument is true.
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# enforce_user - Raises error if URL user doesn't start with alphanumeric characters and argument is true.
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# enforce_sanitization - Raises error if URL includes any HTML/CSS/JS tags and argument is true.
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#
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# Returns an array with [<uri>, <original-hostname>].
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2019-05-29 16:43:07 +00:00
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# rubocop:disable Metrics/CyclomaticComplexity
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# rubocop:disable Metrics/ParameterLists
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def validate!(
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url,
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ports: [],
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schemes: [],
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allow_localhost: false,
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allow_local_network: true,
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ascii_only: false,
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enforce_user: false,
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enforce_sanitization: false,
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dns_rebind_protection: true)
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# rubocop:enable Metrics/CyclomaticComplexity
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# rubocop:enable Metrics/ParameterLists
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2019-04-21 10:03:26 +00:00
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return [nil, nil] if url.nil?
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2017-03-15 20:09:08 +00:00
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2018-11-28 19:06:44 +00:00
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# Param url can be a string, URI or Addressable::URI
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uri = parse_url(url)
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2017-03-15 20:09:08 +00:00
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2019-01-07 17:55:21 +00:00
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validate_html_tags!(uri) if enforce_sanitization
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2019-04-21 10:03:26 +00:00
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hostname = uri.hostname
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2019-01-07 17:55:21 +00:00
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port = get_port(uri)
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2019-04-21 10:03:26 +00:00
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unless internal?(uri)
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validate_scheme!(uri.scheme, schemes)
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validate_port!(port, ports) if ports.any?
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validate_user!(uri.user) if enforce_user
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validate_hostname!(hostname)
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validate_unicode_restriction!(uri) if ascii_only
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end
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2018-03-28 17:27:16 +00:00
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2018-04-02 15:13:23 +00:00
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begin
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2019-04-21 10:03:26 +00:00
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addrs_info = Addrinfo.getaddrinfo(hostname, port, nil, :STREAM).map do |addr|
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2018-11-26 08:45:38 +00:00
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addr.ipv6_v4mapped? ? addr.ipv6_to_ipv4 : addr
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end
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2017-11-07 08:30:38 +00:00
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rescue SocketError
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2019-04-21 10:03:26 +00:00
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return [uri, nil]
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2017-03-15 20:09:08 +00:00
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end
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2019-05-29 16:43:07 +00:00
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protected_uri_with_hostname = enforce_uri_hostname(addrs_info, uri, hostname, dns_rebind_protection)
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2019-04-21 10:03:26 +00:00
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# Allow url from the GitLab instance itself but only for the configured hostname and ports
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2019-05-29 16:43:07 +00:00
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return protected_uri_with_hostname if internal?(uri)
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2019-04-21 10:03:26 +00:00
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2018-04-02 15:13:23 +00:00
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validate_localhost!(addrs_info) unless allow_localhost
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2018-09-06 04:41:59 +00:00
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validate_loopback!(addrs_info) unless allow_localhost
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2018-04-02 15:13:47 +00:00
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validate_local_network!(addrs_info) unless allow_local_network
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2018-08-11 10:38:21 +00:00
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validate_link_local!(addrs_info) unless allow_local_network
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2018-04-02 15:13:23 +00:00
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2019-05-29 16:43:07 +00:00
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protected_uri_with_hostname
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2018-03-28 17:27:16 +00:00
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end
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def blocked_url?(*args)
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validate!(*args)
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2017-03-15 20:09:08 +00:00
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false
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2018-03-28 17:27:16 +00:00
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rescue BlockedUrlError
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true
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2017-03-15 20:09:08 +00:00
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end
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private
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2019-04-21 10:03:26 +00:00
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# Returns the given URI with IP address as hostname and the original hostname respectively
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# in an Array.
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#
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# It checks whether the resolved IP address matches with the hostname. If not, it changes
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# the hostname to the resolved IP address.
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#
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# The original hostname is used to validate the SSL, given in that scenario
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# we'll be making the request to the IP address, instead of using the hostname.
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2019-05-29 16:43:07 +00:00
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def enforce_uri_hostname(addrs_info, uri, hostname, dns_rebind_protection)
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2019-04-21 10:03:26 +00:00
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address = addrs_info.first
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ip_address = address&.ip_address
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2019-05-29 16:43:07 +00:00
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return [uri, nil] unless dns_rebind_protection && ip_address && ip_address != hostname
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2019-04-21 10:03:26 +00:00
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2019-05-29 16:43:07 +00:00
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uri = uri.dup
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uri.hostname = ip_address
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[uri, hostname]
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2019-04-21 10:03:26 +00:00
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end
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2019-01-07 17:55:21 +00:00
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def get_port(uri)
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uri.port || uri.default_port
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end
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def validate_html_tags!(uri)
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uri_str = uri.to_s
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sanitized_uri = ActionController::Base.helpers.sanitize(uri_str, tags: [])
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if sanitized_uri != uri_str
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raise BlockedUrlError, 'HTML/CSS/JS tags are not allowed'
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end
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end
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2018-11-28 19:06:44 +00:00
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def parse_url(url)
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raise Addressable::URI::InvalidURIError if multiline?(url)
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Addressable::URI.parse(url)
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rescue Addressable::URI::InvalidURIError, URI::InvalidURIError
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raise BlockedUrlError, 'URI is invalid'
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end
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def multiline?(url)
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CGI.unescape(url.to_s) =~ /\n|\r/
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end
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2018-06-01 11:43:53 +00:00
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def validate_port!(port, ports)
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2018-04-02 15:13:23 +00:00
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return if port.blank?
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# Only ports under 1024 are restricted
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return if port >= 1024
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2018-06-01 11:43:53 +00:00
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return if ports.include?(port)
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2018-04-02 15:13:23 +00:00
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2018-06-01 11:43:53 +00:00
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raise BlockedUrlError, "Only allowed ports are #{ports.join(', ')}, and any over 1024"
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end
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2019-04-11 06:29:07 +00:00
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def validate_scheme!(scheme, schemes)
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if scheme.blank? || (schemes.any? && !schemes.include?(scheme))
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raise BlockedUrlError, "Only allowed schemes are #{schemes.join(', ')}"
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2018-06-01 11:43:53 +00:00
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end
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2018-04-02 15:13:23 +00:00
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end
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def validate_user!(value)
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return if value.blank?
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return if value =~ /\A\p{Alnum}/
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2017-03-15 20:09:08 +00:00
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2018-04-02 15:13:23 +00:00
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raise BlockedUrlError, "Username needs to start with an alphanumeric character"
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2017-03-15 20:09:08 +00:00
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end
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2018-04-02 15:13:23 +00:00
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def validate_hostname!(value)
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return if value.blank?
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2018-11-26 08:45:38 +00:00
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return if IPAddress.valid?(value)
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2018-04-02 15:13:23 +00:00
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return if value =~ /\A\p{Alnum}/
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2017-08-08 17:36:24 +00:00
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2018-11-26 08:45:38 +00:00
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raise BlockedUrlError, "Hostname or IP address invalid"
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2018-04-02 15:13:23 +00:00
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end
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2018-12-05 20:14:09 +00:00
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def validate_unicode_restriction!(uri)
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return if uri.to_s.ascii_only?
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raise BlockedUrlError, "URI must be ascii only #{uri.to_s.dump}"
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end
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2018-04-02 15:13:23 +00:00
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def validate_localhost!(addrs_info)
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2018-11-26 08:45:38 +00:00
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local_ips = ["::", "0.0.0.0"]
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2018-04-02 15:13:23 +00:00
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local_ips.concat(Socket.ip_address_list.map(&:ip_address))
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return if (local_ips & addrs_info.map(&:ip_address)).empty?
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raise BlockedUrlError, "Requests to localhost are not allowed"
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end
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2018-09-06 04:41:59 +00:00
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def validate_loopback!(addrs_info)
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return unless addrs_info.any? { |addr| addr.ipv4_loopback? || addr.ipv6_loopback? }
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raise BlockedUrlError, "Requests to loopback addresses are not allowed"
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end
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2018-04-02 15:13:23 +00:00
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def validate_local_network!(addrs_info)
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2018-11-26 08:45:38 +00:00
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return unless addrs_info.any? { |addr| addr.ipv4_private? || addr.ipv6_sitelocal? || addr.ipv6_unique_local? }
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2018-04-02 15:13:23 +00:00
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raise BlockedUrlError, "Requests to the local network are not allowed"
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2017-08-08 17:36:24 +00:00
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end
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2018-08-11 10:38:21 +00:00
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def validate_link_local!(addrs_info)
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netmask = IPAddr.new('169.254.0.0/16')
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return unless addrs_info.any? { |addr| addr.ipv6_linklocal? || netmask.include?(addr.ip_address) }
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raise BlockedUrlError, "Requests to the link local network are not allowed"
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end
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2017-03-15 20:09:08 +00:00
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def internal?(uri)
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internal_web?(uri) || internal_shell?(uri)
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end
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def internal_web?(uri)
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2018-11-28 18:37:12 +00:00
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uri.scheme == config.gitlab.protocol &&
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uri.hostname == config.gitlab.host &&
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2017-03-15 20:09:08 +00:00
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(uri.port.blank? || uri.port == config.gitlab.port)
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end
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def internal_shell?(uri)
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2018-11-28 18:37:12 +00:00
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uri.scheme == 'ssh' &&
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uri.hostname == config.gitlab_shell.ssh_host &&
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2017-03-15 20:09:08 +00:00
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(uri.port.blank? || uri.port == config.gitlab_shell.ssh_port)
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end
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def config
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Gitlab.config
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end
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end
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end
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end
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