Class: Rex::Socket::RangeWalker

Inherits:
Object
  • Object
show all
Defined in:
lib/rex/socket/range_walker.rb

Overview

This class provides an interface to enumerating an IP range

This class uses start,stop pairs to represent ranges of addresses. This is very efficient for large numbers of consecutive addresses, and not show-stoppingly inefficient when storing a bunch of non-consecutive addresses, which should be a somewhat unusual case.

Examples:

r = RangeWalker.new("10.1,3.1-7.1-255")
r.include?("10.3.7.255") #=> true
r.length #=> 3570
r.each do |addr|
  # do something with the address
end

Instance Attribute Summary collapse

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(parseme) ⇒ RangeWalker

Initializes a walker instance using the supplied range


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# File 'lib/rex/socket/range_walker.rb', line 41

def initialize(parseme)
  if parseme.is_a? RangeWalker
    @ranges = parseme.ranges.dup
  else
    @ranges = parse(parseme)
  end
  reset
end

Instance Attribute Details

#lengthFixnum (readonly) Also known as: num_ips

The total number of IPs within the range


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# File 'lib/rex/socket/range_walker.rb', line 29

def length
  @length
end

#rangesArray (readonly)

A list of the ranges held in this RangeWalker


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# File 'lib/rex/socket/range_walker.rb', line 36

def ranges
  @ranges
end

Class Method Details

.parse(parseme) ⇒ self, false

Calls the instance method

This is basically only useful for determining if a range can be parsed


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# File 'lib/rex/socket/range_walker.rb', line 56

def self.parse(parseme)
  self.new.parse(parseme)
end

Instance Method Details

#each(&block) ⇒ self

Calls the given block with each address. This is basically a wrapper for #next_ip


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# File 'lib/rex/socket/range_walker.rb', line 263

def each(&block)
  while (ip = next_ip)
    block.call(ip)
  end
  reset

  self
end

#expand_cidr(arg) ⇒ Range, false

Returns an Array with one element, a Rex::Socket::Range defined by the given CIDR block.


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# File 'lib/rex/socket/range_walker.rb', line 280

def expand_cidr(arg)
  start,stop = Rex::Socket.cidr_crack(arg)
  if !start or !stop
    return false
  end
  range = Range.new
  range.start = Rex::Socket.addr_atoi(start)
  range.stop = Rex::Socket.addr_atoi(stop)
  range.options = { :ipv6 => (arg.include?(":")) }

  return range
end

#expand_nmap(arg) ⇒ Object

Expands an nmap-style host range x.x.x.x where x can be simply “*” which means 0-255 or any combination and repitition of:

i,n
n-m
i,n-m
n-m,i

ensuring that n is never greater than m.

non-unique elements will be removed

e.g.:
  10.1.1.1-3,2-2,2 =>  ["10.1.1.1", "10.1.1.2", "10.1.1.3"]
  10.1.1.1-3,7 =>  ["10.1.1.1", "10.1.1.2", "10.1.1.3", "10.1.1.7"]

Returns an array of Ranges


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# File 'lib/rex/socket/range_walker.rb', line 309

def expand_nmap(arg)
  # Can't really do anything with IPv6
  return false if arg.include?(":")

  # nmap calls these errors, but it's hard to catch them with our
  # splitting below, so short-cut them here
  return false if arg.include?(",-") or arg.include?("-,")

  bytes = []
  sections = arg.split('.')
  if sections.length != 4
    # Too many or not enough dots
    return false
  end
  sections.each { |section|
    if section.empty?
      # pretty sure this is an unintentional artifact of the C
      # functions that turn strings into ints, but it sort of makes
      # sense, so why not
      #   "10...1" => "10.0.0.1"
      section = "0"
    end

    if section == "*"
      # I think this ought to be 1-254, but this is how nmap does it.
      section = "0-255"
    elsif section.include?("*")
      return false
    end

    # Break down the sections into ranges like so
    # "1-3,5-7" => ["1-3", "5-7"]
    ranges = section.split(',', -1)
    sets = []
    ranges.each { |r|
      bounds = []
      if r.include?('-')
        # Then it's an actual range, break it down into start,stop
        # pairs:
        #   "1-3" => [ 1, 3 ]
        # if the lower bound is empty, start at 0
        # if the upper bound is empty, stop at 255
        #
        bounds = r.split('-', -1)
        return false if (bounds.length > 2)

        bounds[0] = 0   if bounds[0].nil? or bounds[0].empty?
        bounds[1] = 255 if bounds[1].nil? or bounds[1].empty?
        bounds.map!{|b| b.to_i}
        return false if bounds[0] > bounds[1]
      else
        # Then it's a single value
        bounds[0] = r.to_i
      end
      return false if bounds[0] > 255 or (bounds[1] and bounds[1] > 255)
      return false if bounds[1] and bounds[0] > bounds[1]
      if bounds[1]
        bounds[0].upto(bounds[1]) do |i|
          sets.push(i)
        end
      elsif bounds[0]
        sets.push(bounds[0])
      end
    }
    bytes.push(sets.sort.uniq)
  }

  #
  # Combinitorically squish all of the quads together into a big list of
  # ip addresses, stored as ints
  #
  # e.g.:
  #  [[1],[1],[1,2],[1,2]]
  #  =>
  #  [atoi("1.1.1.1"),atoi("1.1.1.2"),atoi("1.1.2.1"),atoi("1.1.2.2")]
  addrs = []
  for a in bytes[0]
    for b in bytes[1]
      for c in bytes[2]
        for d in bytes[3]
          ip = (a << 24) + (b << 16) + (c << 8) + d
          addrs.push ip
        end
      end
    end
  end

  addrs.sort!
  addrs.uniq!

  rng = Range.new
  rng.options = { :ipv6 => false }
  rng.start = addrs[0]

  ranges = []
  1.upto(addrs.length - 1) do |idx|
    if addrs[idx - 1] + 1 == addrs[idx]
      # Then this address is contained in the current range
      next
    else
      # Then this address is the upper bound for the current range
      rng.stop = addrs[idx - 1]
      ranges.push(rng.dup)
      rng.start = addrs[idx]
    end
  end
  rng.stop = addrs[addrs.length - 1]
  ranges.push(rng.dup)
  return ranges
end

#include?(addr) ⇒ true, false

Returns true if the argument is an ip address that falls within any of the stored ranges.


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# File 'lib/rex/socket/range_walker.rb', line 227

def include?(addr)
  return false if not @ranges
  if (addr.is_a? String)
    addr = Rex::Socket.addr_atoi(addr)
  end
  @ranges.map { |r|
    if addr.between?(r.start, r.stop)
      return true
    end
  }
  return false
end

#include_range?(other) ⇒ Boolean

Returns true if this RangeWalker includes all of the addresses in the given RangeWalker


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# File 'lib/rex/socket/range_walker.rb', line 245

def include_range?(other)
  return false if (!@ranges || @ranges.empty?)
  return false if !other.ranges || other.ranges.empty?

  # Check that all the ranges in +other+ fall within at least one of
  # our ranges.
  other.ranges.all? do |other_range|
    ranges.any? do |range|
      other_range.start.between?(range.start, range.stop) && other_range.stop.between?(range.start, range.stop)
    end
  end
end

#next_ipString Also known as: next

Returns the next IP address.


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# File 'lib/rex/socket/range_walker.rb', line 193

def next_ip
  return false if not valid?
  if (@curr_addr > @ranges[@curr_range_index].stop)
    # Then we are at the end of this range. Grab the next one.

    # Bail if there are no more ranges
    return nil if (@ranges[@curr_range_index+1].nil?)

    @curr_range_index += 1

    @curr_addr = @ranges[@curr_range_index].start
  end
  addr = Rex::Socket.addr_itoa(@curr_addr, @ranges[@curr_range_index].ipv6?)

  if @ranges[@curr_range_index].options[:scope_id]
    addr = addr + '%' + @ranges[@curr_range_index].options[:scope_id]
  end

  @curr_addr += 1
  return addr
end

#parse(parseme) ⇒ self, false

Turn a human-readable range string into ranges we can step through one address at a time.

Allow the following formats:

"a.b.c.d e.f.g.h"
"a.b.c.d, e.f.g.h"

where each chunk is CIDR notation, (e.g. '10.1.1.0/24') or a range in nmap format (see #expand_nmap)

OR this format

"a.b.c.d-e.f.g.h"

where a.b.c.d and e.f.g.h are single IPs and the second must be bigger than the first.


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# File 'lib/rex/socket/range_walker.rb', line 76

def parse(parseme)
  return nil if not parseme
  ranges = []
  parseme.split(', ').map{ |a| a.split(' ') }.flatten.each do |arg|
    opts = {}

    # Handle IPv6 first (support ranges, but not CIDR)
    if arg.include?(":")
      addrs = arg.split('-', 2)

      # Handle a single address
      if addrs.length == 1
        addr, scope_id = addrs[0].split('%')
        opts[:scope_id] = scope_id if scope_id
        opts[:ipv6] = true

        return false unless Rex::Socket.is_ipv6?(addr)
        addr = Rex::Socket.addr_atoi(addr)
        ranges.push(Range.new(addr, addr, opts))
        next
      end

      addr1, scope_id = addrs[0].split('%')
      opts[:scope_id] = scope_id if scope_id

      addr2, scope_id = addrs[0].split('%')
      ( opts[:scope_id] ||= scope_id ) if scope_id

      # Both have to be IPv6 for this to work
      return false unless (Rex::Socket.is_ipv6?(addr1) && Rex::Socket.is_ipv6?(addr2))

      # Handle IPv6 ranges in the form of 2001::1-2001::10
      addr1 = Rex::Socket.addr_atoi(addr1)
      addr2 = Rex::Socket.addr_atoi(addr2)

      ranges.push(Range.new(addr1, addr2, opts))
      next

    # Handle IPv4 CIDR
    elsif arg.include?("/")
      # Then it's CIDR notation and needs special case
      return false if arg =~ /[,-]/ # Improper CIDR notation (can't mix with 1,3 or 1-3 style IP ranges)
      return false if arg.scan("/").size > 1 # ..but there are too many slashes
      ip_part,mask_part = arg.split("/")
      return false if ip_part.nil? or ip_part.empty? or mask_part.nil? or mask_part.empty?
      return false if mask_part !~ /^[0-9]{1,2}$/ # Illegal mask -- numerals only
      return false if mask_part.to_i > 32 # This too -- between 0 and 32.
      if ip_part =~ /^\d{1,3}(\.\d{1,3}){1,3}$/
        return false unless ip_part =~ Rex::Socket::MATCH_IPV4
      end
      begin
        Rex::Socket.getaddress(ip_part) # This allows for "www.metasploit.com/24" which is fun.
      rescue Resolv::ResolvError, ::SocketError, Errno::ENOENT
        return false # Can't resolve the ip_part, so bail.
      end

      expanded = expand_cidr(arg)
      if expanded
        ranges.push(expanded)
      else
        return false
      end

    # Handle hostnames
    elsif arg =~ /[^-0-9,.*]/
      # Then it's a domain name and we should send it on to addr_atoi
      # unmolested to force a DNS lookup.
      begin
        ranges += Rex::Socket.addr_atoi_list(arg).map { |a| Range.new(a, a, opts) }
      rescue Resolv::ResolvError, ::SocketError, Errno::ENOENT
        return false
      end

    # Handle IPv4 ranges
    elsif arg =~ /^([0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3})-([0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3})$/

      # Then it's in the format of 1.2.3.4-5.6.7.8
      # Note, this will /not/ deal with DNS names, or the fancy/obscure 10...1-10...2
      begin
        start, stop = Rex::Socket.addr_atoi($1), Rex::Socket.addr_atoi($2)
        return false if start > stop # The end is greater than the beginning.
        ranges.push(Range.new(start, stop, opts))
      rescue Resolv::ResolvError, ::SocketError, Errno::ENOENT
        return false
      end
    else
      # Returns an array of ranges
      expanded = expand_nmap(arg)
      if expanded
        expanded.each { |r| ranges.push(r) }
      end
    end
  end

  # Remove any duplicate ranges
  ranges = ranges.uniq

  return ranges
end

#resetself

Resets the subnet walker back to its original state.


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# File 'lib/rex/socket/range_walker.rb', line 180

def reset
  return false if not valid?
  @curr_range_index = 0
  @curr_addr = @ranges.first.start
  @length = 0
  @ranges.each { |r| @length += r.length }

  self
end

#valid?Boolean

Whether this RangeWalker's ranges are valid


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# File 'lib/rex/socket/range_walker.rb', line 218

def valid?
  (@ranges && !@ranges.empty?)
end