The explanations before were a bit thin and people not familiar with
setgid inheritance might get confused. Make it easier to understand the
tests.
Cc: Seth Forshee <sforshee@xxxxxxxxxxxxxxxx>
Cc: Eryu Guan <guaneryu@xxxxxxxxx>
Cc: Christoph Hellwig <hch@xxxxxx>
Cc: fstests@xxxxxxxxxxxxxxx
Signed-off-by: Christian Brauner <christian.brauner@xxxxxxxxxx>
---
/* v2 */
- Christian Brauner <brauner@xxxxxxxxxx>:
- fix Seth's mail address in commit message
---
src/idmapped-mounts/idmapped-mounts.c | 19 +++++++++++++++++--
1 file changed, 17 insertions(+), 2 deletions(-)
diff --git a/src/idmapped-mounts/idmapped-mounts.c b/src/idmapped-mounts/idmapped-mounts.c
index 56b26b0c..c53e1942 100644
--- a/src/idmapped-mounts/idmapped-mounts.c
+++ b/src/idmapped-mounts/idmapped-mounts.c
@@ -8128,6 +8128,14 @@ static int setgid_create_idmapped_in_userns(void)
if (wait_for_pid(pid))
goto out;
+ /*
+ * Below we verify that setgid inheritance for a newly created file or
+ * directory works correctly. As part of this we need to verify that
+ * newly created files or directories inherit their gid from their
+ * parent directory. So we change the parent directorie's gid to 1000
+ * and create a file with fs{g,u}id 0 and verify that the newly created
+ * file and directory inherit gid 1000, not 0.
+ */
if (fchownat(t_dir1_fd, "", -1, 1000, AT_SYMLINK_NOFOLLOW | AT_EMPTY_PATH)) {
log_stderr("failure: fchownat");
goto out;
@@ -8172,12 +8180,19 @@ static int setgid_create_idmapped_in_userns(void)
die("failure: is_setgid");
}
- /* Files and directories created in setgid directories inherit
- * the i_gid of the parent directory.
+ /*
+ * In setgid directories newly created files always inherit the
+ * gid from the parent directory. Verify that the file is owned
+ * by gid 1000, not by gid 0.
*/
if (!expected_uid_gid(open_tree_fd, FILE1, 0, 0, 1000))
die("failure: check ownership");
+ /*
+ * In setgid directories newly created directories always
+ * inherit the gid from the parent directory. Verify that the
+ * directory is owned by gid 1000, not by gid 0.
+ */
if (!expected_uid_gid(open_tree_fd, DIR1, 0, 0, 1000))
die("failure: check ownership");
--
2.32.0
