Security Advisories (1)
CVE-2025-40909 (2025-05-30)

Perl threads have a working directory race condition where file operations may target unintended paths. If a directory handle is open at thread creation, the process-wide current working directory is temporarily changed in order to clone that handle for the new thread, which is visible from any third (or more) thread already running. This may lead to unintended operations such as loading code or accessing files from unexpected locations, which a local attacker may be able to exploit. The bug was introduced in commit 11a11ecf4bea72b17d250cfb43c897be1341861e and released in Perl version 5.13.6

NAME

ExtUtils::ParseXS::Utilities - Subroutines used with ExtUtils::ParseXS

SYNOPSIS

use ExtUtils::ParseXS::Utilities qw(
  standard_typemap_locations
  trim_whitespace
  C_string
  valid_proto_string
  process_typemaps
  map_type
  standard_XS_defs
  assign_func_args
  analyze_preprocessor_statements
  set_cond
  Warn
  blurt
  death
  check_conditional_preprocessor_statements
  escape_file_for_line_directive
  report_typemap_failure
);

SUBROUTINES

The following functions are not considered to be part of the public interface. They are documented here for the benefit of future maintainers of this module.

standard_typemap_locations()

  • Purpose

    Provide a list of filepaths where typemap files may be found. The filepaths -- relative paths to files (not just directory paths) -- appear in this list in lowest-to-highest priority.

    The highest priority is to look in the current directory.

    'typemap'

    The second and third highest priorities are to look in the parent of the current directory and a directory called lib/ExtUtils underneath the parent directory.

    '../typemap',
    '../lib/ExtUtils/typemap',

    The fourth through ninth highest priorities are to look in the corresponding grandparent, great-grandparent and great-great-grandparent directories.

    '../../typemap',
    '../../lib/ExtUtils/typemap',
    '../../../typemap',
    '../../../lib/ExtUtils/typemap',
    '../../../../typemap',
    '../../../../lib/ExtUtils/typemap',

    The tenth and subsequent priorities are to look in directories named ExtUtils which are subdirectories of directories found in @INC -- provided a file named typemap actually exists in such a directory. Example:

    '/usr/local/lib/perl5/5.10.1/ExtUtils/typemap',

    However, these filepaths appear in the list returned by standard_typemap_locations() in reverse order, i.e., lowest-to-highest.

    '/usr/local/lib/perl5/5.10.1/ExtUtils/typemap',
    '../../../../lib/ExtUtils/typemap',
    '../../../../typemap',
    '../../../lib/ExtUtils/typemap',
    '../../../typemap',
    '../../lib/ExtUtils/typemap',
    '../../typemap',
    '../lib/ExtUtils/typemap',
    '../typemap',
    'typemap'
  • Arguments

    my @stl = standard_typemap_locations( \@INC );

    Reference to @INC.

  • Return Value

    Array holding list of directories to be searched for typemap files.

trim_whitespace()

  • Purpose

    Perform an in-place trimming of leading and trailing whitespace from the first argument provided to the function.

  • Argument

    trim_whitespace($arg);
  • Return Value

    None. Remember: this is an in-place modification of the argument.

C_string()

  • Purpose

    Escape backslashes (\) in prototype strings.

  • Arguments

    $ProtoThisXSUB = C_string($_);

    String needing escaping.

  • Return Value

    Properly escaped string.

valid_proto_string()

  • Purpose

    Validate prototype string.

  • Arguments

    String needing checking.

  • Return Value

    Upon success, returns the same string passed as argument.

    Upon failure, returns 0.

process_typemaps()

  • Purpose

    Process all typemap files.

  • Arguments

    my $typemaps_object = process_typemaps( $args{typemap}, $pwd );

    List of two elements: typemap element from %args; current working directory.

  • Return Value

    Upon success, returns an ExtUtils::Typemaps object.

map_type()

  • Purpose

    Performs a mapping at several places inside PARAGRAPH loop.

  • Arguments

    $type = map_type($self, $type, $varname);

    List of three arguments.

  • Return Value

    String holding augmented version of second argument.

standard_XS_defs()

  • Purpose

    Writes to the .c output file certain preprocessor directives and function headers needed in all such files.

  • Arguments

    None.

  • Return Value

    Returns true.

assign_func_args()

  • Purpose

    Perform assignment to the func_args attribute.

  • Arguments

    $string = assign_func_args($self, $argsref, $class);

    List of three elements. Second is an array reference; third is a string.

  • Return Value

    String.

analyze_preprocessor_statements()

  • Purpose

    Within each function inside each Xsub, print to the .c output file certain preprocessor statements.

  • Arguments

    ( $self, $XSS_work_idx, $BootCode_ref ) =
      analyze_preprocessor_statements(
        $self, $statement, $XSS_work_idx, $BootCode_ref
      );

    List of four elements.

  • Return Value

    Modifed values of three of the arguments passed to the function. In particular, the XSStack and InitFileCode attributes are modified.

set_cond()

  • Purpose

  • Arguments

  • Return Value

current_line_number()

  • Purpose

    Figures out the current line number in the XS file.

  • Arguments

    $self

  • Return Value

    The current line number.

Warn()

  • Purpose

    Print warnings with line number details at the end.

  • Arguments

    List of text to output.

  • Return Value

    None.

WarnHint()

  • Purpose

    Prints warning with line number details. The last argument is assumed to be a hint string.

  • Arguments

    List of strings to warn, followed by one argument representing a hint. If that argument is defined then it will be split on newlines and output line by line after the main warning.

  • Return Value

    None.

_MsgHint()

  • Purpose

    Constructs an exception message with line number details. The last argument is assumed to be a hint string.

  • Arguments

    List of strings to warn, followed by one argument representing a hint. If that argument is defined then it will be split on newlines and concatenated line by line (parenthesized) after the main message.

  • Return Value

    The constructed string.

blurt()

  • Purpose

  • Arguments

  • Return Value

death()

  • Purpose

  • Arguments

  • Return Value

check_conditional_preprocessor_statements()

  • Purpose

  • Arguments

  • Return Value

escape_file_for_line_directive()

  • Purpose

    Escapes a given code source name (typically a file name but can also be a command that was read from) so that double-quotes and backslashes are escaped.

  • Arguments

    A string.

  • Return Value

    A string with escapes for double-quotes and backslashes.

report_typemap_failure

  • Purpose

    Do error reporting for missing typemaps.

  • Arguments

    The ExtUtils::ParseXS object.

    An ExtUtils::Typemaps object.

    The string that represents the C type that was not found in the typemap.

    Optionally, the string death or blurt to choose whether the error is immediately fatal or not. Default: blurt

  • Return Value

    Returns nothing. Depending on the arguments, this may call death or blurt, the former of which is fatal.