[LTP] pty: Update slave device permission check to allow 0600

[Dan Carpenter]

Systemd changed the default permissions for PTY slave devices from 0620
to 0600 in response to CVE-2024-28085.  Allow either 0620 or 0600 as
valid permissions.

Link: https://security-tracker.debian.org/tracker/CVE-2024-28085
Link: https://github.com/systemd/systemd/commit/a4d18914751e687c9e44f22fe4e5f95b843a45c8
Signed-off-by: Dan Carpenter <dan.carpenter@linaro.org>
Tested-by: Anders Roxell <anders.roxell@linaro.org>

diff --git a/testcases/kernel/pty/common.h b/testcases/kernel/pty/common.h
index 51760b1d39fa..7cda16096d4d 100644
--- a/testcases/kernel/pty/common.h
+++ b/testcases/kernel/pty/common.h
@@ -54,7 +54,8 @@ static inline int open_slave(const int masterfd)
 			st.st_uid, uid);
 	}
 
-	if (st.st_mode != (S_IFCHR | 0620)) {
+	if (st.st_mode != (S_IFCHR | 0620) &&
+	    st.st_mode != (S_IFCHR | 0600)) {
 		tst_brk(TBROK, "unexpected slave device permission: %o",
 			st.st_mode);
 	}