GH-118447: Fix handling of unreadable symlinks in os.path.realpath() (#118489)

Co-authored-by: Nice Zombies <nineteendo19d0@gmail.com>
This commit is contained in:
Barney Gale 2024-05-18 23:40:51 +01:00 committed by GitHub
parent 30b4e9f9c4
commit caf6064a1b
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3 changed files with 32 additions and 13 deletions

View file

@ -471,26 +471,26 @@ symbolic links encountered in the path."""
if not stat.S_ISLNK(st.st_mode):
path = newpath
continue
if newpath in seen:
# Already seen this path
path = seen[newpath]
if path is not None:
# use cached value
continue
# The symlink is not resolved, so we must have a symlink loop.
if strict:
# Raise OSError(errno.ELOOP)
os.stat(newpath)
path = newpath
continue
target = os.readlink(newpath)
except OSError:
if strict:
raise
path = newpath
continue
# Resolve the symbolic link
if newpath in seen:
# Already seen this path
path = seen[newpath]
if path is not None:
# use cached value
continue
# The symlink is not resolved, so we must have a symlink loop.
if strict:
# Raise OSError(errno.ELOOP)
os.stat(newpath)
path = newpath
continue
seen[newpath] = None # not resolved symlink
target = os.readlink(newpath)
if target.startswith(sep):
# Symlink target is absolute; reset resolved path.
path = sep

View file

@ -660,6 +660,23 @@ class PosixPathTest(unittest.TestCase):
safe_rmdir(ABSTFN + "/k")
safe_rmdir(ABSTFN)
@os_helper.skip_unless_symlink
@skip_if_ABSTFN_contains_backslash
@unittest.skipIf(os.chmod not in os.supports_follow_symlinks, "Can't set symlink permissions")
def test_realpath_unreadable_symlink(self):
try:
os.symlink(ABSTFN+"1", ABSTFN)
os.chmod(ABSTFN, 0o000, follow_symlinks=False)
self.assertEqual(realpath(ABSTFN), ABSTFN)
self.assertEqual(realpath(ABSTFN + '/foo'), ABSTFN + '/foo')
self.assertEqual(realpath(ABSTFN + '/../foo'), dirname(ABSTFN) + '/foo')
self.assertEqual(realpath(ABSTFN + '/foo/..'), ABSTFN)
with self.assertRaises(PermissionError):
realpath(ABSTFN, strict=True)
finally:
os.chmod(ABSTFN, 0o755, follow_symlinks=False)
os.unlink(ABSTFN)
def test_relpath(self):
(real_getcwd, os.getcwd) = (os.getcwd, lambda: r"/home/user/bar")
try:

View file

@ -0,0 +1,2 @@
:func:`os.path.realpath` now suppresses any :exc:`OSError` from
:func:`os.readlink` when *strict* mode is disabled (the default).