Class: Rex::Proto::MsDtyp::MsDtypAccessMask

Inherits:
BinData::Record
  • Object
show all
Defined in:
lib/rex/proto/ms_dtyp.rb

Overview

[2.4.3 ACCESS_MASK](learn.microsoft.com/en-us/openspecs/windows_protocols/ms-dtyp/7a53f60e-e730-4dfe-bbe9-b21b62eb790b)

Constant Summary collapse

ALL = 
MsDtypAccessMask.new({ gr: 1, gw: 1, gx: 1, ga: 1, ma: 1, as: 1, sy: 1, wo: 1, wd: 1, rc: 1, de: 1, protocol: 0xffff })
NONE = 
MsDtypAccessMask.new({ gr: 0, gw: 0, gx: 0, ga: 0, ma: 0, as: 0, sy: 0, wo: 0, wd: 0, rc: 0, de: 0, protocol: 0 })

Class Method Summary collapse

Instance Method Summary collapse

Class Method Details

.from_sddl_text(sddl_text) ⇒ Object 



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# File 'lib/rex/proto/ms_dtyp.rb', line 90

def self.from_sddl_text(sddl_text)
  if sddl_text =~ /\A0x[0-9a-fA-F]{1,8}\Z/
    return self.read([sddl_text.delete_prefix('0x').to_i(16)].pack('L<'))
  end

  access_mask = self.new
  sddl_text.split(/(G[ARWX]|RC|SD|WD|WO|RP|WP|CC|DC|LC|SW|LO|DT|CR|F[ARWX]|K[ARWX]|N[RWX])/).each do |right|
    case right
    # generic access rights
    when 'GA', 'GR', 'GW', 'GX'
      access_mask.send("#{right.downcase}=", true)
    # standard access rights
    when 'RC'
      access_mask.rc = true
    when 'SD'
      access_mask.de = true
    when 'WD', 'WO'
      access_mask.send("#{right.downcase}=", true)
    # directory service object access rights
    when 'RP'
      access_mask.protocol |= 16
    when 'WP'
      access_mask.protocol |= 32
    when 'CC'
      access_mask.protocol |= 1
    when 'DC'
      access_mask.protocol |= 2
    when 'LC'
      access_mask.protocol |= 4
    when 'SW'
      access_mask.protocol |= 8
    when 'LO'
      access_mask.protocol |= 128
    when 'DT'
      access_mask.protocol |= 64
    when 'CR'
      access_mask.protocol |= 256
    # file access rights
    when 'FA'
      access_mask.protocol |= 0x1ff
      access_mask.de = true
      access_mask.rc = true
      access_mask.wd = true
      access_mask.wo = true
      access_mask.sy = true
    when 'FR'
      access_mask.protocol |= 0x89
    when 'FW'
      access_mask.protocol |= 0x116
    when 'FX'
      access_mask.protocol |= 0xa0
    # registry key access rights
    when 'KA'
      access_mask.protocol |= 0x3f
      access_mask.de = true
      access_mask.rc = true
      access_mask.wd = true
      access_mask.wo = true
    when 'KR'
      access_mask.protocol |= 0x19
    when 'KW'
      access_mask.protocol |= 0x06
    when 'KX'
      access_mask.protocol |= 0x19
    when 'NR', 'NW', 'NX'
      raise SDDLParseError.new('unsupported ACE access right: ' + right)
    when ''
    else
      raise SDDLParseError.new('unknown ACE access right: ' + right)
    end
  end

  access_mask
end

Instance Method Details

#permissions ⇒ Object

Obtain an array of the abbreviated names of permissions that the access mask specifies.

Returns:

  • Returns nil if the permissions can't be represented as an array of abbreviations.



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# File 'lib/rex/proto/ms_dtyp.rb', line 41

def permissions
  if (protocol & 0b1111111000000000) != 0 || ma == 1 || as == 1
    return nil
  end

  permissions = []
  permissions << :GA if ga == 1
  permissions << :GR if gr == 1
  permissions << :GW if gw == 1
  permissions << :GX if gx == 1

  file_access_mask = protocol & 0b000111111111
  permissions << :FA if file_access_mask == 0b000111111111 && de == 1 && rc == 1 && wd == 1 && wo == 1 && sy == 1
  permissions << :FR if file_access_mask == 0b000010001001
  permissions << :FW if file_access_mask == 0b000100010110
  permissions << :FX if file_access_mask == 0b000010100000

  # windows does not reduce registry access flags (i.e. KA, KR, KW) so ignore them here to match it

  permissions << :CC if (protocol & 0b000000000001) != 0 && !permissions.include?(:FA) && !permissions.include?(:FR)
  permissions << :DC if (protocol & 0b000000000010) != 0 && !permissions.include?(:FA) && !permissions.include?(:FW)
  permissions << :LC if (protocol & 0b000000000100) != 0 && !permissions.include?(:FA) && !permissions.include?(:FW)
  permissions << :SW if (protocol & 0b000000001000) != 0 && !permissions.include?(:FA) && !permissions.include?(:FR)
  permissions << :RP if (protocol & 0b000000010000) != 0 && !permissions.include?(:FA) && !permissions.include?(:FW)
  permissions << :WP if (protocol & 0b000000100000) != 0 && !permissions.include?(:FA) && !permissions.include?(:FX)
  permissions << :DT if (protocol & 0b000001000000) != 0 && !permissions.include?(:FA)
  permissions << :LO if (protocol & 0b000010000000) != 0 && !permissions.include?(:FA)
  permissions << :CR if (protocol & 0b000100000000) != 0 && !permissions.include?(:FA)

  permissions << :SD if de == 1 && !permissions.include?(:FA)
  permissions << :RC if rc == 1 && !permissions.include?(:FA)
  permissions << :WD if wd == 1 && !permissions.include?(:FA)
  permissions << :WO if wo == 1 && !permissions.include?(:FA)

  permissions
end

#to_sddl_text ⇒ Object 



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# File 'lib/rex/proto/ms_dtyp.rb', line 78

def to_sddl_text
  perms = permissions

  if perms.nil?
    # if one of these conditions are true, we can't reduce this to a set of flags so dump it as hex
    return "0x#{to_binary_s.unpack1('L<').to_s(16).rjust(8, '0')}"
  end


  permissions.map(&:to_s).join
end