Skip to content

Commit

Permalink
GH-118447: Fix handling of unreadable symlinks in os.path.realpath() (
Browse files Browse the repository at this point in the history
#118489)

Co-authored-by: Nice Zombies <nineteendo19d0@gmail.com>
  • Loading branch information
barneygale and nineteendo authored May 18, 2024
1 parent 30b4e9f commit caf6064
Show file tree
Hide file tree
Showing 3 changed files with 32 additions and 13 deletions.
26 changes: 13 additions & 13 deletions Lib/posixpath.py
Original file line number Diff line number Diff line change
Expand Up @@ -471,26 +471,26 @@ def realpath(filename, *, strict=False):
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
Expand Down
17 changes: 17 additions & 0 deletions Lib/test/test_posixpath.py
Original file line number Diff line number Diff line change
Expand Up @@ -660,6 +660,23 @@ def test_realpath_resolve_first(self):
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:
Expand Down
Original file line number Diff line number Diff line change
@@ -0,0 +1,2 @@
:func:`os.path.realpath` now suppresses any :exc:`OSError` from
:func:`os.readlink` when *strict* mode is disabled (the default).

0 comments on commit caf6064

Please sign in to comment.