# -*- ruby encoding: utf-8 -*-
##
# Class Net::LDAP::Filter is used to constrain LDAP searches. An object of
# this class is passed to Net::LDAP#search in the parameter :filter.
#
# Net::LDAP::Filter supports the complete set of search filters available in
# LDAP, including conjunction, disjunction and negation (AND, OR, and NOT).
# This class supplants the (infamous) RFC 2254 standard notation for
# specifying LDAP search filters.
#--
# NOTE: This wording needs to change as we will be supporting LDAPv3 search
# filter strings (RFC 4515).
#++
#
# Here's how to code the familiar "objectclass is present" filter:
# f = Net::LDAP::Filter.present("objectclass")
#
# The object returned by this code can be passed directly to the
# <tt>:filter</tt> parameter of Net::LDAP#search.
#
# See the individual class and instance methods below for more examples.
class Net::LDAP::Filter
##
# Known filter types.
FilterTypes = [:ne, :eq, :ge, :le, :and, :or, :not, :ex, :bineq]
def initialize(op, left, right) #:nodoc:
unless FilterTypes.include?(op)
raise Net::LDAP::OperatorError, "Invalid or unsupported operator #{op.inspect} in LDAP Filter."
end
@op = op
@left = left
@right = right
end
class << self
# We don't want filters created except using our custom constructors.
private :new
##
# Creates a Filter object indicating that the value of a particular
# attribute must either be present or match a particular string.
#
# Specifying that an attribute is 'present' means only directory entries
# which contain a value for the particular attribute will be selected by
# the filter. This is useful in case of optional attributes such as
# <tt>mail.</tt> Presence is indicated by giving the value "*" in the
# second parameter to #eq. This example selects only entries that have
# one or more values for <tt>sAMAccountName:</tt>
#
# f = Net::LDAP::Filter.eq("sAMAccountName", "*")
#
# To match a particular range of values, pass a string as the second
# parameter to #eq. The string may contain one or more "*" characters as
# wildcards: these match zero or more occurrences of any character. Full
# regular-expressions are <i>not</i> supported due to limitations in the
# underlying LDAP protocol. This example selects any entry with a
# <tt>mail</tt> value containing the substring "anderson":
#
# f = Net::LDAP::Filter.eq("mail", "*anderson*")
#
# This filter does not perform any escaping
def eq(attribute, value)
new(:eq, attribute, value)
end
##
# Creates a Filter object indicating a binary comparison.
# this prevents the search data from being forced into a UTF-8 string.
#
# This is primarily used for Microsoft Active Directory to compare
# GUID values.
#
# # for guid represented as hex charecters
# guid = "6a31b4a12aa27a41aca9603f27dd5116"
# guid_bin = [guid].pack("H*")
# f = Net::LDAP::Filter.bineq("objectGUID", guid_bin)
#
# This filter does not perform any escaping.
def bineq(attribute, value)
new(:bineq, attribute, value)
end
##
# Creates a Filter object indicating extensible comparison. This Filter
# object is currently considered EXPERIMENTAL.
#
# sample_attributes = ['cn:fr', 'cn:fr.eq',
# 'cn:1.3.6.1.4.1.42.2.27.9.4.49.1.3', 'cn:dn:fr', 'cn:dn:fr.eq']
# attr = sample_attributes.first # Pick an extensible attribute
# value = 'roberts'
#
# filter = "#{attr}:=#{value}" # Basic String Filter
# filter = Net::LDAP::Filter.ex(attr, value) # Net::LDAP::Filter
#
# # Perform a search with the Extensible Match Filter
# Net::LDAP.search(:filter => filter)
#--
# The LDIF required to support the above examples on the OpenDS LDAP
# server:
#
# version: 1
#
# dn: dc=example,dc=com
# objectClass: domain
# objectClass: top
# dc: example
#
# dn: ou=People,dc=example,dc=com
# objectClass: organizationalUnit
# objectClass: top
# ou: People
#
# dn: uid=1,ou=People,dc=example,dc=com
# objectClass: person
# objectClass: organizationalPerson
# objectClass: inetOrgPerson
# objectClass: top
# cn:: csO0YsOpcnRz
# sn:: YsO0YiByw7Riw6lydHM=
# givenName:: YsO0Yg==
# uid: 1
#
# =Refs:
# * http://www.ietf.org/rfc/rfc2251.txt
# * http://www.novell.com/documentation/edir88/edir88/?page=/documentation/edir88/edir88/data/agazepd.html
# * https://docs.opends.org/2.0/page/SearchingUsingInternationalCollationRules
#++
def ex(attribute, value)
new(:ex, attribute, value)
end
##
# Creates a Filter object indicating that a particular attribute value
# is either not present or does not match a particular string; see
# Filter::eq for more information.
#
# This filter does not perform any escaping
def ne(attribute, value)
new(:ne, attribute, value)
end
##
# Creates a Filter object indicating that the value of a particular
# attribute must match a particular string. The attribute value is
# escaped, so the "*" character is interpreted literally.
def equals(attribute, value)
new(:eq, attribute, escape(value))
end
##
# Creates a Filter object indicating that the value of a particular
# attribute must begin with a particular string. The attribute value is
# escaped, so the "*" character is interpreted literally.
def begins(attribute, value)
new(:eq, attribute, escape(value) + "*")
end
##
# Creates a Filter object indicating that the value of a particular
# attribute must end with a particular string. The attribute value is
# escaped, so the "*" character is interpreted literally.
def ends(attribute, value)
new(:eq, attribute, "*" + escape(value))
end
##
# Creates a Filter object indicating that the value of a particular
# attribute must contain a particular string. The attribute value is
# escaped, so the "*" character is interpreted literally.
def contains(attribute, value)
new(:eq, attribute, "*" + escape(value) + "*")
end
##
# Creates a Filter object indicating that a particular attribute value
# is greater than or equal to the specified value.
def ge(attribute, value)
new(:ge, attribute, value)
end
##
# Creates a Filter object indicating that a particular attribute value
# is less than or equal to the specified value.
def le(attribute, value)
new(:le, attribute, value)
end
##
# Joins two or more filters so that all conditions must be true. Calling
# <tt>Filter.join(left, right)</tt> is the same as <tt>left &
# right</tt>.
#
# # Selects only entries that have an <tt>objectclass</tt> attribute.
# x = Net::LDAP::Filter.present("objectclass")
# # Selects only entries that have a <tt>mail</tt> attribute that begins
# # with "George".
# y = Net::LDAP::Filter.eq("mail", "George*")
# # Selects only entries that meet both conditions above.
# z = Net::LDAP::Filter.join(x, y)
def join(left, right)
new(:and, left, right)
end
##
# Creates a disjoint comparison between two or more filters. Selects
# entries where either the left or right side are true. Calling
# <tt>Filter.intersect(left, right)</tt> is the same as <tt>left |
# right</tt>.
#
# # Selects only entries that have an <tt>objectclass</tt> attribute.
# x = Net::LDAP::Filter.present("objectclass")
# # Selects only entries that have a <tt>mail</tt> attribute that begins
# # with "George".
# y = Net::LDAP::Filter.eq("mail", "George*")
# # Selects only entries that meet either condition above.
# z = x | y
def intersect(left, right)
new(:or, left, right)
end
##
# Negates a filter. Calling <tt>Fitler.negate(filter)</tt> i s the same
# as <tt>~filter</tt>.
#
# # Selects only entries that do not have an <tt>objectclass</tt>
# # attribute.
# x = ~Net::LDAP::Filter.present("objectclass")
def negate(filter)
new(:not, filter, nil)
end
##
# This is a synonym for #eq(attribute, "*"). Also known as #present and
# #pres.
def present?(attribute)
eq(attribute, "*")
end
alias_method :present, :present?
alias_method :pres, :present?
# http://tools.ietf.org/html/rfc4515 lists these exceptions from UTF1
# charset for filters. All of the following must be escaped in any normal
# string using a single backslash ('\') as escape.
#
ESCAPES = {
"\0" => '00', # NUL = %x00 ; null character
'*' => '2A', # ASTERISK = %x2A ; asterisk ("*")
'(' => '28', # LPARENS = %x28 ; left parenthesis ("(")
')' => '29', # RPARENS = %x29 ; right parenthesis (")")
'\\' => '5C', # ESC = %x5C ; esc (or backslash) ("\")
}
# Compiled character class regexp using the keys from the above hash.
ESCAPE_RE = Regexp.new(
"[" +
ESCAPES.keys.map { |e| Regexp.escape(e) }.join +
"]")
##
# Escape a string for use in an LDAP filter
def escape(string)
string.gsub(ESCAPE_RE) { |char| "\\" + ESCAPES[char] }
end
##
# Converts an LDAP search filter in BER format to an Net::LDAP::Filter
# object. The incoming BER object most likely came to us by parsing an
# LDAP searchRequest PDU. See also the comments under #to_ber, including
# the grammar snippet from the RFC.
#--
# We're hardcoding the BER constants from the RFC. These should be
# broken out insto constants.
def parse_ber(ber)
case ber.ber_identifier
when 0xa0 # context-specific constructed 0, "and"
ber.map { |b| parse_ber(b) }.inject { |memo, obj| memo & obj }
when 0xa1 # context-specific constructed 1, "or"
ber.map { |b| parse_ber(b) }.inject { |memo, obj| memo | obj }
when 0xa2 # context-specific constructed 2, "not"
~parse_ber(ber.first)
when 0xa3 # context-specific constructed 3, "equalityMatch"
if ber.last == "*"
else
eq(ber.first, ber.last)
end
when 0xa4 # context-specific constructed 4, "substring"
str = ""
final = false
ber.last.each do |b|
case b.ber_identifier
when 0x80 # context-specific primitive 0, SubstringFilter "initial"
raise Net::LDAP::SubstringFilterError, "Unrecognized substring filter; bad initial value." if str.length > 0
str += escape(b)
when 0x81 # context-specific primitive 0, SubstringFilter "any"
str += "*#{escape(b)}"
when 0x82 # context-specific primitive 0, SubstringFilter "final"
str += "*#{escape(b)}"
final = true
end
end
str += "*" unless final
eq(ber.first.to_s, str)
when 0xa5 # context-specific constructed 5, "greaterOrEqual"
ge(ber.first.to_s, ber.last.to_s)
when 0xa6 # context-specific constructed 6, "lessOrEqual"
le(ber.first.to_s, ber.last.to_s)
when 0x87 # context-specific primitive 7, "present"
# call to_s to get rid of the BER-identifiedness of the incoming string.
present?(ber.to_s)
when 0xa9 # context-specific constructed 9, "extensible comparison"
raise Net::LDAP::SearchFilterError, "Invalid extensible search filter, should be at least two elements" if ber.size < 2
# Reassembles the extensible filter parts
# (["sn", "2.4.6.8.10", "Barbara Jones", '1'])
type = value = dn = rule = nil
ber.each do |element|
case element.ber_identifier
when 0x81 then rule=element
when 0x82 then type=element
when 0x83 then value=element
when 0x84 then dn='dn'
end
end
attribute = ''
attribute << type if type
attribute << ":#{dn}" if dn
attribute << ":#{rule}" if rule
ex(attribute, value)
else
raise Net::LDAP::BERInvalidError, "Invalid BER tag-value (#{ber.ber_identifier}) in search filter."
end
end
##
# Converts an LDAP filter-string (in the prefix syntax specified in RFC-2254)
# to a Net::LDAP::Filter.
def construct(ldap_filter_string)
FilterParser.parse(ldap_filter_string)
end
alias_method :from_rfc2254, :construct
alias_method :from_rfc4515, :construct
##
# Convert an RFC-1777 LDAP/BER "Filter" object to a Net::LDAP::Filter
# object.
#--
# TODO, we're hardcoding the RFC-1777 BER-encodings of the various
# filter types. Could pull them out into a constant.
#++
def parse_ldap_filter(obj)
case obj.ber_identifier
when 0x87 # present. context-specific primitive 7.
eq(obj.to_s, "*")
when 0xa3 # equalityMatch. context-specific constructed 3.
eq(obj[0], obj[1])
else
raise Net::LDAP::SearchFilterTypeUnknownError, "Unknown LDAP search-filter type: #{obj.ber_identifier}"
end
end
end
##
# Joins two or more filters so that all conditions must be true.
#
# # Selects only entries that have an <tt>objectclass</tt> attribute.
# x = Net::LDAP::Filter.present("objectclass")
# # Selects only entries that have a <tt>mail</tt> attribute that begins
# # with "George".
# y = Net::LDAP::Filter.eq("mail", "George*")
# # Selects only entries that meet both conditions above.
# z = x & y
def &(filter)
self.class.join(self, filter)
end
##
# Creates a disjoint comparison between two or more filters. Selects
# entries where either the left or right side are true.
#
# # Selects only entries that have an <tt>objectclass</tt> attribute.
# x = Net::LDAP::Filter.present("objectclass")
# # Selects only entries that have a <tt>mail</tt> attribute that begins
# # with "George".
# y = Net::LDAP::Filter.eq("mail", "George*")
# # Selects only entries that meet either condition above.
# z = x | y
def |(filter)
self.class.intersect(self, filter)
end
##
# Negates a filter.
#
# # Selects only entries that do not have an <tt>objectclass</tt>
# # attribute.
# x = ~Net::LDAP::Filter.present("objectclass")
def ~@
self.class.negate(self)
end
##
# Equality operator for filters, useful primarily for constructing unit tests.
def ==(filter)
# 20100320 AZ: We need to come up with a better way of doing this. This
# is just nasty.
str = "[@op,@left,@right]"
self.instance_eval(str) == filter.instance_eval(str)
end
def to_raw_rfc2254
case @op
when :ne
"!(#{@left}=#{@right})"
when :eq, :bineq
"#{@left}=#{@right}"
when :ex
"#{@left}:=#{@right}"
when :ge
"#{@left}>=#{@right}"
when :le
"#{@left}<=#{@right}"
when :and
"&(#{@left.to_raw_rfc2254})(#{@right.to_raw_rfc2254})"
when :or
"|(#{@left.to_raw_rfc2254})(#{@right.to_raw_rfc2254})"
when :not
"!(#{@left.to_raw_rfc2254})"
end
end
##
# Converts the Filter object to an RFC 2254-compatible text format.
def to_rfc2254
"(#{to_raw_rfc2254})"
end
def to_s
to_rfc2254
end
##
# Converts the filter to BER format.
#--
# Filter ::=
# CHOICE {
# and [0] SET OF Filter,
# or [1] SET OF Filter,
# not [2] Filter,
# equalityMatch [3] AttributeValueAssertion,
# substrings [4] SubstringFilter,
# greaterOrEqual [5] AttributeValueAssertion,
# lessOrEqual [6] AttributeValueAssertion,
# present [7] AttributeType,
# approxMatch [8] AttributeValueAssertion,
# extensibleMatch [9] MatchingRuleAssertion
# }
#
# SubstringFilter ::=
# SEQUENCE {
# type AttributeType,
# SEQUENCE OF CHOICE {
# initial [0] LDAPString,
# any [1] LDAPString,
# final [2] LDAPString
# }
# }
#
# MatchingRuleAssertion ::=
# SEQUENCE {
# matchingRule [1] MatchingRuleId OPTIONAL,
# type [2] AttributeDescription OPTIONAL,
# matchValue [3] AssertionValue,
# dnAttributes [4] BOOLEAN DEFAULT FALSE
# }
#
# Matching Rule Suffixes
# Less than [.1] or .[lt]
# Less than or equal to [.2] or [.lte]
# Equality [.3] or [.eq] (default)
# Greater than or equal to [.4] or [.gte]
# Greater than [.5] or [.gt]
# Substring [.6] or [.sub]
#
#++
def to_ber
case @op
when :eq
if @right == "*" # presence test
@left.to_s.to_ber_contextspecific(7)
elsif @right.to_s =~ /[*]/ # substring
# Parsing substrings is a little tricky. We use String#split to
# break a string into substrings delimited by the * (star)
# character. But we also need to know whether there is a star at the
# head and tail of the string, so we use a limit parameter value of
# -1: "If negative, there is no limit to the number of fields
# returned, and trailing null fields are not suppressed."
#
# 20100320 AZ: This is much simpler than the previous verison. Also,
# unnecessary regex escaping has been removed.
ary = @right.split(/[*]+/, -1)
if ary.first.empty?
first = nil
ary.shift
else
first = unescape(ary.shift).to_ber_contextspecific(0)
end
if ary.last.empty?
last = nil
ary.pop
else
last = unescape(ary.pop).to_ber_contextspecific(2)
end
seq = ary.map { |e| unescape(e).to_ber_contextspecific(1) }
seq.unshift first if first
seq.push last if last
[@left.to_s.to_ber, seq.to_ber].to_ber_contextspecific(4)
else # equality
[@left.to_s.to_ber, unescape(@right).to_ber].to_ber_contextspecific(3)
end
when :bineq
# make sure data is not forced to UTF-8
[@left.to_s.to_ber, unescape(@right).to_ber_bin].to_ber_contextspecific(3)
when :ex
seq = []
unless @left =~ /^([-;\w]*)(:dn)?(:(\w+|[.\w]+))?$/
raise Net::LDAP::BadAttributeError, "Bad attribute #{@left}"
end
type, dn, rule = $1, $2, $4
seq << rule.to_ber_contextspecific(1) unless rule.to_s.empty? # matchingRule
seq << type.to_ber_contextspecific(2) unless type.to_s.empty? # type
seq << unescape(@right).to_ber_contextspecific(3) # matchingValue
seq << "1".to_ber_contextspecific(4) unless dn.to_s.empty? # dnAttributes
seq.to_ber_contextspecific(9)
when :ge
[@left.to_s.to_ber, unescape(@right).to_ber].to_ber_contextspecific(5)
when :le
[@left.to_s.to_ber, unescape(@right).to_ber].to_ber_contextspecific(6)
when :ne
[self.class.eq(@left, @right).to_ber].to_ber_contextspecific(2)
when :and
ary = [@left.coalesce(:and), @right.coalesce(:and)].flatten
ary.map(&:to_ber).to_ber_contextspecific(0)
when :or
ary = [@left.coalesce(:or), @right.coalesce(:or)].flatten
ary.map(&:to_ber).to_ber_contextspecific(1)
when :not
[@left.to_ber].to_ber_contextspecific(2)
end
end
##
# Perform filter operations against a user-supplied block. This is useful
# when implementing an LDAP directory server. The caller's block will be
# called with two arguments: first, a symbol denoting the "operation" of
# the filter; and second, an array consisting of arguments to the
# operation. The user-supplied block (which is MANDATORY) should perform
# some desired application-defined processing, and may return a
# locally-meaningful object that will appear as a parameter in the :and,
# :or and :not operations detailed below.
#
# A typical object to return from the user-supplied block is an array of
# Net::LDAP::Filter objects.
#
# These are the possible values that may be passed to the user-supplied
# block:
# * :equalityMatch (the arguments will be an attribute name and a value
# to be matched);
# * :substrings (two arguments: an attribute name and a value containing
# one or more "*" characters);
# * :present (one argument: an attribute name);
# * :greaterOrEqual (two arguments: an attribute name and a value to be
# compared against);
# * :lessOrEqual (two arguments: an attribute name and a value to be
# compared against);
# * :and (two or more arguments, each of which is an object returned
# from a recursive call to #execute, with the same block;
# * :or (two or more arguments, each of which is an object returned from
# a recursive call to #execute, with the same block; and
# * :not (one argument, which is an object returned from a recursive
# call to #execute with the the same block.
def execute(&block)
case @op
when :eq
if @right == "*"
yield :present, @left
elsif @right.index '*'
yield :substrings, @left, @right
else
yield :equalityMatch, @left, @right
end
when :ge
yield :greaterOrEqual, @left, @right
when :le
yield :lessOrEqual, @left, @right
when :or, :and
yield @op, (@left.execute(&block)), (@right.execute(&block))
when :not
yield @op, (@left.execute(&block))
end || []
end
##
# This is a private helper method for dealing with chains of ANDs and ORs
# that are longer than two. If BOTH of our branches are of the specified
# type of joining operator, then return both of them as an array (calling
# coalesce recursively). If they're not, then return an array consisting
# only of self.
def coalesce(operator) #:nodoc:
if @op == operator
[@left.coalesce(operator), @right.coalesce(operator)]
else
[self]
end
end
##
#--
# We got a hash of attribute values.
# Do we match the attributes?
# Return T/F, and call match recursively as necessary.
#++
def match(entry)
case @op
when :eq
if @right == "*"
l = entry[@left] and l.length > 0
else
l = entry[@left] and l = Array(l) and l.index(@right)
end
else
raise Net::LDAP::FilterTypeUnknownError, "Unknown filter type in match: #{@op}"
end
end
##
# Converts escaped characters (e.g., "\\28") to unescaped characters
# @note slawson20170317: Don't attempt to unescape 16 byte binary data which we assume are objectGUIDs
# The binary form of 5936AE79-664F-44EA-BCCB-5C39399514C6 triggers a BINARY -> UTF-8 conversion error
def unescape(right)
right = right.to_s
if right.length == 16 && right.encoding == Encoding::BINARY
right
else
right.to_s.gsub(/\\([a-fA-F\d]{2})/) { [$1.hex].pack("U") }
end
end
private :unescape
##
# Parses RFC 2254-style string representations of LDAP filters into Filter
# object hierarchies.
class FilterParser #:nodoc:
##
# The constructed filter.
attr_reader :filter
class << self
private :new
##
# Construct a filter tree from the provided string and return it.
def parse(ldap_filter_string)
new(ldap_filter_string).filter
end
end
def initialize(str)
require 'strscan' # Don't load strscan until we need it.
@filter = parse(StringScanner.new(str))
raise Net::LDAP::FilterSyntaxInvalidError, "Invalid filter syntax." unless @filter
end
##
# Parse the string contained in the StringScanner provided. Parsing
# tries to parse a standalone expression first. If that fails, it tries
# to parse a parenthesized expression.
def parse(scanner)
parse_filter_branch(scanner) or parse_paren_expression(scanner)
end
private :parse
##
# Join ("&") and intersect ("|") operations are presented in branches.
# That is, the expression <tt>(&(test1)(test2)</tt> has two branches:
# test1 and test2. Each of these is parsed separately and then pushed
# into a branch array for filter merging using the parent operation.
#
# This method parses the branch text out into an array of filter
# objects.
def parse_branches(scanner)
branches = []
while branch = parse_paren_expression(scanner)
branches << branch
end
branches
end
private :parse_branches
##
# Join ("&") and intersect ("|") operations are presented in branches.
# That is, the expression <tt>(&(test1)(test2)</tt> has two branches:
# test1 and test2. Each of these is parsed separately and then pushed
# into a branch array for filter merging using the parent operation.
#
# This method calls #parse_branches to generate the branch list and then
# merges them into a single Filter tree by calling the provided
# operation.
def merge_branches(op, scanner)
filter = nil
branches = parse_branches(scanner)
if branches.size >= 1
filter = branches.shift
while not branches.empty?
filter = filter.__send__(op, branches.shift)
end
end
filter
end
private :merge_branches
def parse_paren_expression(scanner)
if scanner.scan(/\s*\(\s*/)
expr = if scanner.scan(/\s*\&\s*/)
merge_branches(:&, scanner)
elsif scanner.scan(/\s*\|\s*/)
merge_branches(:|, scanner)
elsif scanner.scan(/\s*\!\s*/)
br = parse_paren_expression(scanner)
~br if br
else
parse_filter_branch(scanner)
end
if expr and scanner.scan(/\s*\)\s*/)
expr
end
end
end
private :parse_paren_expression
##
# This parses a given expression inside of parentheses.
def parse_filter_branch(scanner)
scanner.scan(/\s*/)
if token = scanner.scan(/[-\w:.;]*[\w]/)
scanner.scan(/\s*/)
if op = scanner.scan(/<=|>=|!=|:=|=/)
scanner.scan(/\s*/)
if value = scanner.scan(/(?:[-\[\]{}\w*.+\/:@=,#\$%&!'^~\s\xC3\x80-\xCA\xAF]|[^\x00-\x7F]|\\[a-fA-F\d]{2})+/u)
# 20100313 AZ: Assumes that "(uid=george*)" is the same as
# "(uid=george* )". The standard doesn't specify, but I can find
# no examples that suggest otherwise.
value.strip!
case op
when "="
Net::LDAP::Filter.eq(token, value)
when "!="
Net::LDAP::Filter.ne(token, value)
when "<="
Net::LDAP::Filter.le(token, value)
when ">="
Net::LDAP::Filter.ge(token, value)
when ":="
Net::LDAP::Filter.ex(token, value)
end
end
end
end
end
private :parse_filter_branch
end # class Net::LDAP::FilterParser
end # class Net::LDAP::Filter