Module: Puppet::Util::SELinux

Included in:
SELFileContext, FileType
Defined in:
lib/puppet/util/selinux.rb

Instance Method Summary collapse

Instance Method Details

#get_selinux_current_context(file) ⇒ Object

Retrieve and return the full context of the file. If we don’t have SELinux support or if the SELinux call fails then return nil.



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# File 'lib/puppet/util/selinux.rb', line 26

def get_selinux_current_context(file)
  return nil unless selinux_support?
  retval = Selinux.lgetfilecon(file)
  if retval == -1
    return nil
  end
  retval[1]
end

#get_selinux_default_context(file) ⇒ Object

Retrieve and return the default context of the file. If we don’t have SELinux support or if the SELinux call fails to file a default then return nil.



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# File 'lib/puppet/util/selinux.rb', line 37

def get_selinux_default_context(file)
  return nil unless selinux_support?
  # If the filesystem has no support for SELinux labels, return a default of nil
  # instead of what matchpathcon would return
  return nil unless selinux_label_support?(file)
  # If the file exists we should pass the mode to matchpathcon for the most specific
  # matching.  If not, we can pass a mode of 0.
  begin
    filestat = file_lstat(file)
    mode = filestat.mode
  rescue Errno::EACCES, Errno::ENOENT
    mode = 0
  end

  retval = Selinux.matchpathcon(file, mode)
  if retval == -1
    return nil
  end
  retval[1]
end

#parse_selinux_context(component, context) ⇒ Object

Take the full SELinux context returned from the tools and parse it out to the three (or four) component parts. Supports :seluser, :selrole, :seltype, and on systems with range support, :selrange.



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# File 'lib/puppet/util/selinux.rb', line 61

def parse_selinux_context(component, context)
  if context.nil? or context == "unlabeled"
    return nil
  end
  components = /^([^\s:]+):([^\s:]+):([^\s:]+)(?::([\sa-zA-Z0-9:,._-]+))?$/.match(context)
  unless components
    raise Puppet::Error, _("Invalid context to parse: %{context}") % { context: context }
  end
  case component
  when :seluser
    components[1]
  when :selrole
    components[2]
  when :seltype
    components[3]
  when :selrange
    components[4]
  else
    raise Puppet::Error, _("Invalid SELinux parameter type")
  end
end

#selinux_category_to_label(category) ⇒ String

selinux_category_to_label is an internal method that converts all selinux categories to their internal representation, avoiding potential issues when mcstransd is not functional.

It is not marked private because it is needed by File’s selcontext.rb, but it is not intended for use outside of Puppet’s code.

Parameters:

  • category (String) —

    An selinux category, such as “s0” or “SystemLow”

Returns:

  • (String) —

    the numeric category name, such as “s0”



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# File 'lib/puppet/util/selinux.rb', line 158

def selinux_category_to_label(category)
  # We don't cache this, but there's already a ton of duplicate work
  # in the selinux handling code.

  path = Selinux.selinux_translations_path
  begin
    File.open(path).each do |line|
      line.strip!
      next if line.empty?
      next if line[0] == "#" # skip comments
      line.gsub!(/[[:space:]]+/m, '')
      mapping = line.split("=", 2)
      if category == mapping[1]
        return mapping[0]
      end
    end
  rescue SystemCallError => ex
    log_exception(ex)
    raise Puppet::Error, _("Could not open SELinux category translation file %{path}.") % { context: context }
  end

  category
end

#selinux_support? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/puppet/util/selinux.rb', line 16

def selinux_support?
  return false unless defined?(Selinux)
  if Selinux.is_selinux_enabled == 1
    return true
  end
  false
end

#set_selinux_context(file, value, component = false) ⇒ Object

This updates the actual SELinux label on the file. You can update only a single component or update the entire context. The caveat is that since setting a partial context makes no sense the file has to already exist. Puppet (via the File resource) will always just try to set components, even if all values are specified by the manifest. I believe that the OS should always provide at least a fall-through context though on any well-running system.



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# File 'lib/puppet/util/selinux.rb', line 90

def set_selinux_context(file, value, component = false)
  return nil unless selinux_support? && selinux_label_support?(file)

  if component
    # Must first get existing context to replace a single component
    context = Selinux.lgetfilecon(file)[1]
    if context == -1
      # We can't set partial context components when no context exists
      # unless/until we can find a way to make Puppet call this method
      # once for all selinux file label attributes.
      Puppet.warning _("Can't set SELinux context on file unless the file already has some kind of context")
      return nil
    end
    context = context.split(':')
    case component
      when :seluser
        context[0] = value
      when :selrole
        context[1] = value
      when :seltype
        context[2] = value
      when :selrange
        context[3] = value
      else
        raise ArgumentError, _("set_selinux_context component must be one of :seluser, :selrole, :seltype, or :selrange")
    end
    context = context.join(':')
  else
    context = value
  end

  retval = Selinux.lsetfilecon(file, context)
  if retval == 0
    return true
  else
    Puppet.warning _("Failed to set SELinux context %{context} on %{file}") % { context: context, file: file }
    return false
  end
end

#set_selinux_default_context(file) ⇒ Object

Since this call relies on get_selinux_default_context it also needs a full non-relative path to the file. Fortunately, that seems to be all Puppet uses. This will set the file’s SELinux context to the policy’s default context (if any) if it differs from the context currently on the file.



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# File 'lib/puppet/util/selinux.rb', line 135

def set_selinux_default_context(file)
  new_context = get_selinux_default_context(file)
  return nil unless new_context
  cur_context = get_selinux_current_context(file)
  if new_context != cur_context
    set_selinux_context(file, new_context)
    return new_context
  end
  nil
end