[Python-checkins] bpo-40014: Fix os.getgrouplist() on macOS (GH-19118)

Mon Mar 23 15:18:49 EDT 2020

https://github.com/python/cpython/commit/21bee0bd71e1ad270274499f9f58194ebb52e236
commit: 21bee0bd71e1ad270274499f9f58194ebb52e236
branch: 3.8
author: Miss Islington (bot) <31488909+miss-islington at users.noreply.github.com>
committer: GitHub <noreply at github.com>
date: 2020年03月23日T12:18:41-07:00
summary:
bpo-40014: Fix os.getgrouplist() on macOS (GH-19118)
On macOS, getgrouplist() returns a non-zero value without setting
errno if the group list is too small. Double the list size and call
it again in this case.
(cherry picked from commit 8ec7370c89aa522602eb9604086ce9f09770953d)
Co-authored-by: Victor Stinner <vstinner at python.org>
files:
A Misc/NEWS.d/next/Library/2020-03-23-17-52-00.bpo-40014.Ya70VG.rst
M Modules/posixmodule.c

diff --git a/Misc/NEWS.d/next/Library/2020-03-23-17-52-00.bpo-40014.Ya70VG.rst b/Misc/NEWS.d/next/Library/2020-03-23-17-52-00.bpo-40014.Ya70VG.rst
new file mode 100644
index 0000000000000..58f14fa9a72d0
--- /dev/null
+++ b/Misc/NEWS.d/next/Library/2020-03-23-17-52-00.bpo-40014.Ya70VG.rst
@@ -0,0 +1,3 @@
+Fix ``os.getgrouplist()``: on macOS, the ``getgrouplist()`` function returns a
+non-zero value without setting ``errno`` if the group list is too small. Double
+the list size and call it again in this case.
diff --git a/Modules/posixmodule.c b/Modules/posixmodule.c
index 2f791d1df953a..be7ebb67d21ee 100644
--- a/Modules/posixmodule.c
+++ b/Modules/posixmodule.c
@@ -6914,10 +6914,29 @@ posix_getgrouplist(PyObject *self, PyObject *args)
 if (groups == NULL)
 return PyErr_NoMemory();
 
+#ifdef __APPLE__
+ while (getgrouplist(user, basegid, groups, &ngroups)) {
+ /* On macOS, getgrouplist() returns a non-zero value without setting
+ errno if the group list is too small. Double the list size and call
+ it again in this case. */
+ PyMem_Free(groups);
+
+ if (ngroups > INT_MAX / 2) {
+ return PyErr_NoMemory();
+ }
+ ngroups *= 2;
+
+ groups = PyMem_New(int, ngroups);
+ if (groups == NULL) {
+ return PyErr_NoMemory();
+ }
+ }
+#else
 if (getgrouplist(user, basegid, groups, &ngroups) == -1) {
 PyMem_Del(groups);
 return posix_error();
 }
+#endif
 
 #ifdef _Py_MEMORY_SANITIZER
 /* Clang memory sanitizer libc intercepts don't know getgrouplist. */
