Add a selftest for idmapping the merged overlay mount itself. It
applies an idmapping to a freshly created (still detached) overlay
mount with mount_setattr(MOUNT_ATTR_IDMAP) and checks that:
- getattr reports ownership mapped through the mount idmap;
- a file created through the idmapped mount is stored on the upper
layer with the corresponding overlay-final id;
- chown through the idmapped mount round-trips;
- an nfs_export overlay can be idmapped and decodable file handles
round-trip through it with correctly mapped ownership.
The layers live on a private tmpfs and are owned by the host id so that
they map to id 0 through the test idmapping, allowing the root caller
to operate on them.
Link: https://patch.msgid.link/20260615-work-idmapped-overlayfs-v1-9-7381632aa402@kernel.org
Reviewed-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Christian Brauner (Amutable) <brauner@kernel.org>
set_layers_via_fds.c calls open_tree() directly, but that wrapper is
not provided by all C libraries, so the test fails to link with
"undefined reference to open_tree" on toolchains without it.
Use sys_open_tree() from ../wrappers.h, the syscall wrapper already
used for move_mount(), fsmount() and friends here. This is also a
prerequisite for building the new idmapped_mounts test added to this
directory.
Link: https://patch.msgid.link/20260615-work-idmapped-overlayfs-v1-8-7381632aa402@kernel.org
Reviewed-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Christian Brauner (Amutable) <brauner@kernel.org>
This follow-up patch completes centralization of kselftest.h and
ksefltest_harness.h includes in remaining seltests files, replacing all
relative paths with a non-relative paths using shared -I include path in
lib.mk
Tested with gcc-13.3 and clang-18.1, and cross-compiled successfully on
riscv, arm64, x86_64 and powerpc arch.
[reddybalavignesh9979@gmail.com: add selftests include path for kselftest.h]
Link: https://lkml.kernel.org/r/20251017090201.317521-1-reddybalavignesh9979@gmail.com
Link: https://lkml.kernel.org/r/20251016104409.68985-1-reddybalavignesh9979@gmail.com
Signed-off-by: Bala-Vignesh-Reddy <reddybalavignesh9979@gmail.com>
Suggested-by: Andrew Morton <akpm@linux-foundation.org>
Link: https://lore.kernel.org/lkml/20250820143954.33d95635e504e94df01930d0@linux-foundation.org/
Reviewed-by: Wei Yang <richard.weiyang@gmail.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: David S. Miller <davem@davemloft.net>
Cc: Eric Dumazet <edumazet@google.com>
Cc: Günther Noack <gnoack@google.com>
Cc: Jakub Kacinski <kuba@kernel.org>
Cc: Liam Howlett <liam.howlett@oracle.com>
Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Mickael Salaun <mic@digikod.net>
Cc: Ming Lei <ming.lei@redhat.com>
Cc: Paolo Abeni <pabeni@redhat.com>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Simon Horman <horms@kernel.org>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
This is not an overlayfs specific header.
Reviewed-by: John Hubbard <jhubbard@nvidia.com>
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Link: https://lore.kernel.org/20250509133240.529330-2-amir73il@gmail.com
Reviewed-by: Christian Brauner <brauner@kernel.org>
Signed-off-by: Christian Brauner <brauner@kernel.org>
CC mount_setattr_test
In file included from mount_setattr_test.c:24:
mount_setattr_test.c: In function ‘mount_setattr_mount_detached_mount_on_detached_mount_and_attach’:
mount_setattr_test.c:1850:60: error: ‘STATX_MNT_ID_UNIQUE’ undeclared (first use in this function); did you mean ‘STATX_MNT_ID’?
1850 | ASSERT_EQ(statx(fd_tree_subdir, "", AT_EMPTY_PATH, STATX_MNT_ID_UNIQUE, &stx), 0);
| ^~~~~~~~~~~~~~~~~~~
../kselftest_harness.h:757:20: note: in definition of macro ‘__EXPECT’
757 | __typeof__(_expected) __exp = (_expected); \
| ^~~~~~~~~
mount_setattr_test.c:1850:9: note: in expansion of macro ‘ASSERT_EQ’
1850 | ASSERT_EQ(statx(fd_tree_subdir, "", AT_EMPTY_PATH, STATX_MNT_ID_UNIQUE, &stx), 0);
| ^~~~~~~~~
mount_setattr_test.c:1850:60: note: each undeclared identifier is reported only once for each function it appears in
1850 | ASSERT_EQ(statx(fd_tree_subdir, "", AT_EMPTY_PATH, STATX_MNT_ID_UNIQUE, &stx), 0);
| ^~~~~~~~~~~~~~~~~~~
../kselftest_harness.h:757:20: note: in definition of macro ‘__EXPECT’
757 | __typeof__(_expected) __exp = (_expected); \
| ^~~~~~~~~
mount_setattr_test.c:1850:9: note: in expansion of macro ‘ASSERT_EQ’
1850 | ASSERT_EQ(statx(fd_tree_subdir, "", AT_EMPTY_PATH, STATX_MNT_ID_UNIQUE, &stx), 0);
| ^~~~~~~~~
Signed-off-by: Christian Brauner <brauner@kernel.org>
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Merge tag 'vfs-6.15-rc1.overlayfs' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs
Pull vfs overlayfs updates from Christian Brauner:
"Currently overlayfs uses the mounter's credentials for its
override_creds() calls. That provides a consistent permission model.
This patches allows a caller to instruct overlayfs to use its
credentials instead. The caller must be located in the same user
namespace hierarchy as the user namespace the overlayfs instance will
be mounted in. This provides a consistent and simple security model.
With this it is possible to e.g., mount an overlayfs instance where
the mounter must have CAP_SYS_ADMIN but the credentials used for
override_creds() have dropped CAP_SYS_ADMIN. It also allows the usage
of custom fs{g,u}id different from the callers and other tweaks"
* tag 'vfs-6.15-rc1.overlayfs' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs:
selftests/ovl: add third selftest for "override_creds"
selftests/ovl: add second selftest for "override_creds"
selftests/filesystems: add utils.{c,h}
selftests/ovl: add first selftest for "override_creds"
ovl: allow to specify override credentials
Fix build error on ppc64:
dev_in_maps.c: In function ‘get_file_dev_and_inode’:
dev_in_maps.c:60:59: error: format ‘%llu’ expects argument of type
‘long long unsigned int *’, but argument 7 has type ‘__u64 *’ {aka ‘long
unsigned int *’} [-Werror=format=]
By switching to unsigned long long for u64 for ppc64 builds.
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>
One build issue comes up due to both mount.h included dev_in_maps.c
In file included from dev_in_maps.c:10:
/usr/include/sys/mount.h:35:3: error: expected identifier before numeric constant
35 | MS_RDONLY = 1, /* Mount read-only. */
| ^~~~~~~~~
In file included from dev_in_maps.c:13:
Remove one of them to solve conflict, another error comes up:
dev_in_maps.c:170:6: error: implicit declaration of function ‘mount’ [-Werror=implicit-function-declaration]
170 | if (mount(NULL, "/", NULL, MS_SLAVE | MS_REC, NULL) == -1) {
| ^~~~~
cc1: all warnings being treated as errors
and then , add sys_mount definition to solve it
After both above, dev_in_maps.c can be built correctly on my mache(gcc 10.2,glibc-2.32,kernel-5.10)
Signed-off-by: Hu Yadi <hu.yadi@h3c.com>
Link: https://lore.kernel.org/r/20240112074059.29673-1-hu.yadi@h3c.com
Acked-by: Andrei Vagin <avagin@google.com>
Signed-off-by: Christian Brauner <brauner@kernel.org>
When mapping a file on overlayfs, the file stored in ->vm_file is a
backing file whose f_inode is on the underlying filesystem. We need to
verify that /proc/pid/maps contains numbers of the overlayfs file, but
not its backing file.
Cc: Amir Goldstein <amir73il@gmail.com>
Cc: Alexander Mikhalitsyn <alexander@mihalicyn.com>
Signed-off-by: Andrei Vagin <avagin@google.com>
Link: https://lore.kernel.org/r/20231214064439.1023011-2-avagin@google.com
Reviewed-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Christian Brauner <brauner@kernel.org>
