Class: Asciidoctor::PathResolver

Inherits:
Object
  • Object
show all
Includes:
Logging
Defined in:
lib/asciidoctor/path_resolver.rb

Overview

> start path /etc is outside of jail: /path/to/docs’

Constant Summary collapse

DOT = 
'.'
DOT_DOT = 
'..'
DOT_SLASH = 
'./'
SLASH = 
'/'
BACKSLASH = 
'\\'
DOUBLE_SLASH = 
'//'
URI_CLASSLOADER = 
'uri:classloader:'
WindowsRootRx = 
%r(^(?:[a-zA-Z]:)?[\\/])

Instance Attribute Summary collapse

Instance Method Summary collapse

Methods included from Logging

#logger, #message_with_context

Constructor Details

#initialize(file_separator = nil, working_dir = nil) ⇒ PathResolver

Construct a new instance of PathResolver, optionally specifying the file separator (to override the system default) and the working directory (to override the present working directory). The working directory will be expanded to an absolute path inside the constructor.

Parameters:

  • file_separator (defaults to: nil) —

    the String file separator to use for path operations (optional, default: File::ALT_SEPARATOR or File::SEPARATOR)

  • working_dir (defaults to: nil) —

    the String working directory (optional, default: Dir.pwd)



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# File 'lib/asciidoctor/path_resolver.rb', line 127

def initialize file_separator = nil, working_dir = nil
  @file_separator = file_separator || ::File::ALT_SEPARATOR || ::File::SEPARATOR
  @working_dir = working_dir ? ((root? working_dir) ? (posixify working_dir) : (::File.expand_path working_dir)) : ::Dir.pwd
  @_partition_path_sys = {}
  @_partition_path_web = {}
end

Instance Attribute Details

#file_separator ⇒ Object 



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# File 'lib/asciidoctor/path_resolver.rb', line 115

def file_separator
  @file_separator
end

#working_dir ⇒ Object 



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# File 'lib/asciidoctor/path_resolver.rb', line 116

def working_dir
  @working_dir
end

Instance Method Details

#absolute_path?(path) ⇒ Boolean Also known as: root?

Check whether the specified path is an absolute path.

This operation considers both posix paths and Windows paths. The path does not have to be posixified beforehand. This operation does not handle URIs.

Unix absolute paths start with a slash. UNC paths can start with a slash or backslash. Windows roots can start with a drive letter.

Parameters:

  • path —

    the String path to check

  • returns —

    a Boolean indicating whether the path is an absolute root path

Returns:

  • (Boolean) 


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# File 'lib/asciidoctor/path_resolver.rb', line 145

def absolute_path? path
  (path.start_with? SLASH) || (@file_separator == BACKSLASH && (WindowsRootRx.match? path))
end

#descends_from?(path, base) ⇒ Boolean

Determine whether path descends from base.

If path equals base, or base is a parent of path, return true.

Parameters:

  • path —

    The String path to check. Can be relative.

  • base —

    The String base path to check against. Can be relative.

  • returns —

    If path descends from base, return the offset, otherwise false.

Returns:

  • (Boolean) 


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# File 'lib/asciidoctor/path_resolver.rb', line 203

def descends_from? path, base
  if base == path
    0
  elsif base == SLASH
    (path.start_with? SLASH) && 1
  else
    (path.start_with? base + SLASH) && (base.length + 1)
  end
end

#expand_path(path) ⇒ Object

Expand the specified path by converting the path to a posix path, resolving parent references (..), and removing self references (.).

Parameters:

  • path —

    the String path to expand

  • returns —

    a String path as a posix path with parent references resolved and self references removed.

  • The —

    result will be relative if the path is relative and absolute if the path is absolute.



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# File 'lib/asciidoctor/path_resolver.rb', line 260

def expand_path path
  path_segments, path_root = partition_path path
  if path.include? DOT_DOT
    resolved_segments = []
    path_segments.each do |segment|
      segment == DOT_DOT ? resolved_segments.pop : resolved_segments << segment
    end
    join_path resolved_segments, path_root
  else
    join_path path_segments, path_root
  end
end

#join_path(segments, root = nil) ⇒ Object

Join the segments using the posix file separator (since Ruby knows how to work with paths specified this way, regardless of OS). Use the root, if specified, to construct an absolute path. Otherwise join the segments as a relative path.

Parameters:

  • segments —

    a String Array of path segments

  • root (defaults to: nil) —

    a String path root (optional, default: nil)

  • returns —

    a String path formed by joining the segments using the posix file

  • separator —

    and prepending the root, if specified



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# File 'lib/asciidoctor/path_resolver.rb', line 337

def join_path segments, root = nil
  root ? %(#{root}#{segments.join SLASH}) : (segments.join SLASH)
end

#partition_path(path, web = nil) ⇒ Object

Partition the path into path segments and remove self references (.) and the trailing slash, if present. Prior to being partitioned, the path is converted to a posix path.

Parent references are not resolved by this method since the consumer often needs to handle this resolution in a certain context (checking for the breach of a jail, for instance).

Parameters:

  • path —

    the String path to partition

  • web (defaults to: nil) —

    a Boolean indicating whether the path should be handled as a web path (optional, default: false)

Returns:

  • a 2-item Array containing the Array of String path segments and the path root (e.g., ‘/’, ‘./’, ‘c:/’, or ‘//’), which is nil unless the path is absolute.



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# File 'lib/asciidoctor/path_resolver.rb', line 285

def partition_path path, web = nil
  if (result = (cache = web ? @_partition_path_web : @_partition_path_sys)[path])
    return result
  end

  posix_path = posixify path

  if web
    # ex. /sample/path
    if web_root? posix_path
      root = SLASH
    # ex. ./sample/path
    elsif posix_path.start_with? DOT_SLASH
      root = DOT_SLASH
    end
    # otherwise ex. sample/path
  elsif root? posix_path
    # ex. //sample/path
    if unc? posix_path
      root = DOUBLE_SLASH
    # ex. /sample/path
    elsif posix_path.start_with? SLASH
      root = SLASH
    # ex. uri:classloader:sample/path (or uri:classloader:/sample/path)
    elsif posix_path.start_with? URI_CLASSLOADER
      root = posix_path.slice 0, URI_CLASSLOADER.length
    # ex. C:/sample/path (or file:///sample/path in browser environment)
    else
      root = posix_path.slice 0, (posix_path.index SLASH) + 1
    end
  # ex. ./sample/path
  elsif posix_path.start_with? DOT_SLASH
    root = DOT_SLASH
  end
  # otherwise ex. sample/path

  path_segments = (root ? (posix_path.slice root.length, posix_path.length) : posix_path).split SLASH
  # strip out all dot entries
  path_segments.delete DOT
  cache[path] = [path_segments, root]
end

#posixify(path) ⇒ Object Also known as: posixfy

Normalize path by converting any backslashes to forward slashes

Parameters:

  • path —

    the String path to normalize

  • returns —

    a String path with any backslashes replaced with forward slashes



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# File 'lib/asciidoctor/path_resolver.rb', line 244

def posixify path
  if path
    @file_separator == BACKSLASH && (path.include? BACKSLASH) ? (path.tr BACKSLASH, SLASH) : path
  else
    ''
  end
end

#relative_path(path, base) ⇒ String

Calculate the relative path to this absolute path from the specified base directory

If neither path or base are absolute paths, the path is not contained within the base directory, or the relative path cannot be computed, the original path is returned work is done.

Parameters:

  • path (String) —

    an absolute filename.

  • base (String) —

    an absolute base directory.

Returns:

  • (String) —

    Return the String relative path of the specified path calculated from the base directory.



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# File 'lib/asciidoctor/path_resolver.rb', line 223

def relative_path path, base
  if root? path
    if (offset = descends_from? path, base)
      path.slice offset, path.length
    else
      begin
        (Pathname.new path).relative_path_from(Pathname.new base).to_s
      rescue
        path
      end
    end
  else
    path
  end
end

#system_path(target, start = nil, jail = nil, opts = {}) ⇒ Object

Securely resolve a system path

Resolves the target to an absolute path on the current filesystem. The target is assumed to be relative to the start path, jail path, or working directory (specified in the constructor), in that order. If a jail path is specified, the resolved path is forced to descend from the jail path. If a jail path is not provided, the resolved path may be any location on the system. If the target is an absolute path, use it as is (unless it breaches the jail path). Expands all parent and self references in the resolved path.

Parameters:

  • target —

    the String target path

  • start (defaults to: nil) —

    the String start path from which to resolve a relative target; falls back to jail, if specified, or the working directory specified in the constructor (default: nil)

  • jail (defaults to: nil) —

    the String jail path to which to confine the resolved path, if specified; must be an absolute path (default: nil)

  • opts (defaults to: {}) —

    an optional Hash of options to control processing (default: {}): * :recover is used to control whether the processor should automatically recover when an illegal path is encountered * :target_name is used in messages to refer to the path being resolved

Returns:

  • an absolute String path relative to the start path, if specified, and confined to the jail path, if specified. The path is posixified and all parent and self references in the path are expanded.



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# File 'lib/asciidoctor/path_resolver.rb', line 363

def system_path target, start = nil, jail = nil, opts = {}
  if jail
    raise ::SecurityError, %(Jail is not an absolute path: #{jail}) unless root? jail
    #raise ::SecurityError, %(Jail is not a canonical path: #{jail}) if jail.include? DOT_DOT
    jail = posixify jail
  end

  if target
    if root? target
      target_path = expand_path target
      if jail && !(descends_from? target_path, jail)
        if opts.fetch :recover, true
          logger.warn %(#{opts[:target_name] || 'path'} is outside of jail; recovering automatically)
          target_segments, = partition_path target_path
          jail_segments, jail_root = partition_path jail
          return join_path jail_segments + target_segments, jail_root
        else
          raise ::SecurityError, %(#{opts[:target_name] || 'path'} #{target} is outside of jail: #{jail} (disallowed in safe mode))
        end
      end
      return target_path
    else
      target_segments, = partition_path target
    end
  else
    target_segments = []
  end

  if target_segments.empty?
    if start.nil_or_empty?
      return jail || @working_dir
    elsif root? start
      if jail
        start = posixify start
      else
        return expand_path start
      end
    else
      target_segments, = partition_path start
      start = jail || @working_dir
    end
  elsif start.nil_or_empty?
    start = jail || @working_dir
  elsif root? start
    start = posixify start if jail
  else
    #start = system_path start, jail, jail, opts
    start = %(#{(jail || @working_dir).chomp '/'}/#{start})
  end

  # both jail and start have been posixified at this point if jail is set
  if jail && (recheck = !(descends_from? start, jail)) && @file_separator == BACKSLASH
    start_segments, start_root = partition_path start
    jail_segments, jail_root = partition_path jail
    if start_root != jail_root
      if opts.fetch :recover, true
        logger.warn %(start path for #{opts[:target_name] || 'path'} is outside of jail root; recovering automatically)
        start_segments = jail_segments
        recheck = false
      else
        raise ::SecurityError, %(start path for #{opts[:target_name] || 'path'} #{start} refers to location outside jail root: #{jail} (disallowed in safe mode))
      end
    end
  else
    start_segments, jail_root = partition_path start
  end

  if (resolved_segments = start_segments + target_segments).include? DOT_DOT
    unresolved_segments, resolved_segments = resolved_segments, []
    if jail
      jail_segments, = partition_path jail unless jail_segments
      warned = false
      unresolved_segments.each do |segment|
        if segment == DOT_DOT
          if resolved_segments.size > jail_segments.size
            resolved_segments.pop
          elsif opts.fetch :recover, true
            unless warned
              logger.warn %(#{opts[:target_name] || 'path'} has illegal reference to ancestor of jail; recovering automatically)
              warned = true
            end
          else
            raise ::SecurityError, %(#{opts[:target_name] || 'path'} #{target} refers to location outside jail: #{jail} (disallowed in safe mode))
          end
        else
          resolved_segments << segment
        end
      end
    else
      unresolved_segments.each do |segment|
        segment == DOT_DOT ? resolved_segments.pop : resolved_segments << segment
      end
    end
  end

  if recheck
    target_path = join_path resolved_segments, jail_root
    if descends_from? target_path, jail
      target_path
    elsif opts.fetch :recover, true
      logger.warn %(#{opts[:target_name] || 'path'} is outside of jail; recovering automatically)
      jail_segments, = partition_path jail unless jail_segments
      join_path jail_segments + target_segments, jail_root
    else
      raise ::SecurityError, %(#{opts[:target_name] || 'path'} #{target} is outside of jail: #{jail} (disallowed in safe mode))
    end
  else
    join_path resolved_segments, jail_root
  end
end

#unc?(path) ⇒ Boolean

Determine if the path is a UNC (root) path

Parameters:

  • path —

    the String path to check

  • returns —

    a Boolean indicating whether the path is a UNC path

Returns:

  • (Boolean) 


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# File 'lib/asciidoctor/path_resolver.rb', line 182

def unc? path
  path.start_with? DOUBLE_SLASH
end

#web_path(target, start = nil) ⇒ Object

Resolve a web path from the target and start paths. The main function of this operation is to resolve any parent references and remove any self references.

The target is assumed to be a path, not a qualified URI. That check should happen before this method is invoked.

Parameters:

  • target —

    the String target path

  • start (defaults to: nil) —

    the String start (i.e., parent) path

  • returns —

    a String path that joins the target path with the

  • start (defaults to: nil) —

    path with any parent references resolved and self

  • references —

    removed



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# File 'lib/asciidoctor/path_resolver.rb', line 487

def web_path target, start = nil
  target = posixify target
  start = posixify start

  unless start.nil_or_empty? || (web_root? target)
    target, uri_prefix = extract_uri_prefix %(#{start}#{(start.end_with? SLASH) ? '' : SLASH}#{target})
  end

  # use this logic instead if we want to normalize target if it contains a URI
  #unless web_root? target
  #  target, uri_prefix = extract_uri_prefix target if preserve_uri_target
  #  target, uri_prefix = extract_uri_prefix %(#{start}#{SLASH}#{target}) unless uri_prefix || start.nil_or_empty?
  #end

  target_segments, target_root = partition_path target, true
  resolved_segments = []
  target_segments.each do |segment|
    if segment == DOT_DOT
      if resolved_segments.empty?
        resolved_segments << segment unless target_root && target_root != DOT_SLASH
      elsif resolved_segments[-1] == DOT_DOT
        resolved_segments << segment
      else
        resolved_segments.pop
      end
    else
      resolved_segments << segment
      # checking for empty would eliminate repeating forward slashes
      #resolved_segments << segment unless segment.empty?
    end
  end

  if (resolved_path = join_path resolved_segments, target_root).include? ' '
    resolved_path = resolved_path.gsub ' ', '%20'
  end

  uri_prefix ? %(#{uri_prefix}#{resolved_path}) : resolved_path
end

#web_root?(path) ⇒ Boolean

Determine if the path is an absolute (root) web path

Parameters:

  • path —

    the String path to check

  • returns —

    a Boolean indicating whether the path is an absolute (root) web path

Returns:

  • (Boolean) 


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# File 'lib/asciidoctor/path_resolver.rb', line 191

def web_root? path
  path.start_with? SLASH
end