selftests/filesystems: add chown() test for anonymous inodes

Test that anonymous inodes cannot be chown()ed.

Link: https://lore.kernel.org/20250407-work-anon_inode-v1-6-53a44c20d44e@kernel.org
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Christian Brauner <brauner@kernel.org>

diff --git a/tools/testing/selftests/filesystems/.gitignore b/tools/testing/selftests/filesystems/.gitignore
index 828b66a10c63f51fca9d1622b056b00cba666ca3..7afa58e2bb2002078417d0d0a8ccd9a2b878f2c4 100644 (file)
--- a/tools/testing/selftests/filesystems/.gitignore
+++ b/tools/testing/selftests/filesystems/.gitignore
@@ -2,3 +2,4 @@
 dnotify_test
 devpts_pts
 file_stressor
+anon_inode_test

diff --git a/tools/testing/selftests/filesystems/Makefile b/tools/testing/selftests/filesystems/Makefile
index 66305fc34c60daf115dff97771e05400c73dc071..b02326193fee52867db30f0e711e26c0b3efbeb8 100644 (file)
--- a/tools/testing/selftests/filesystems/Makefile
+++ b/tools/testing/selftests/filesystems/Makefile
@@ -1,7 +1,7 @@
 # SPDX-License-Identifier: GPL-2.0
 
 CFLAGS += $(KHDR_INCLUDES)
-TEST_GEN_PROGS := devpts_pts file_stressor
+TEST_GEN_PROGS := devpts_pts file_stressor anon_inode_test
 TEST_GEN_PROGS_EXTENDED := dnotify_test
 
 include ../lib.mk

diff --git a/tools/testing/selftests/filesystems/anon_inode_test.c b/tools/testing/selftests/filesystems/anon_inode_test.c
new file mode 100644 (file)
index 0000000..f2cae8f
--- /dev/null
+++ b/tools/testing/selftests/filesystems/anon_inode_test.c
@@ -0,0 +1,26 @@
+// SPDX-License-Identifier: GPL-2.0
+#define _GNU_SOURCE
+#define __SANE_USERSPACE_TYPES__
+
+#include <fcntl.h>
+#include <stdio.h>
+#include <sys/stat.h>
+
+#include "../kselftest_harness.h"
+#include "overlayfs/wrappers.h"
+
+TEST(anon_inode_no_chown)
+{
+       int fd_context;
+
+       fd_context = sys_fsopen("tmpfs", 0);
+       ASSERT_GE(fd_context, 0);
+
+       ASSERT_LT(fchown(fd_context, 1234, 5678), 0);
+       ASSERT_EQ(errno, EOPNOTSUPP);
+
+       EXPECT_EQ(close(fd_context), 0);
+}
+
+TEST_HARNESS_MAIN
+