closes bpo-34540: Convert shutil._call_external_zip to use subprocess rather than distutils.spawn. (GH-8985)

Lib/shutil.py

@@ -413,17 +413,21 @@ def _make_tarball(base_name, base_dir, compress="gzip", verbose=0, dry_run=0,
 
     return archive_name
 
-def _call_external_zip(base_dir, zip_filename, verbose=False, dry_run=False):
+def _call_external_zip(base_dir, zip_filename, verbose, dry_run, logger):
     # XXX see if we want to keep an external call here
     if verbose:
         zipoptions = "-r"
     else:
         zipoptions = "-rq"
-    from distutils.errors import DistutilsExecError
-    from distutils.spawn import spawn
+    cmd = ["zip", zipoptions, zip_filename, base_dir]
+    if logger is not None:
+        logger.info(' '.join(cmd))
+    if dry_run:
+        return
+    import subprocess
     try:
-        spawn(["zip", zipoptions, zip_filename, base_dir], dry_run=dry_run)
-    except DistutilsExecError:
+        subprocess.check_call(cmd)
+    except subprocess.CalledProcessError:
         # XXX really should distinguish between "couldn't find
         # external 'zip' command" and "zip failed".
         raise ExecError, \
@@ -458,7 +462,7 @@ def _make_zipfile(base_name, base_dir, verbose=0, dry_run=0, logger=None):
         zipfile = None
 
     if zipfile is None:
-        _call_external_zip(base_dir, zip_filename, verbose, dry_run)
+        _call_external_zip(base_dir, zip_filename, verbose, dry_run, logger)
     else:
         if logger is not None:
             logger.info("creating '%s' and adding '%s' to it",

Misc/NEWS.d/next/Security/2018-08-28-22-11-54.bpo-34540.gfQ0TM.rst

@@ -0,0 +1,3 @@
+When ``shutil.make_archive`` falls back to the external ``zip`` problem, it
+uses :mod:`subprocess` to invoke it rather than :mod:`distutils.spawn`. This
+closes a possible shell injection vector.