diff options
| author | Amir Goldstein <amir73il@gmail.com> | 2026-01-29 11:02:12 +0100 |
|---|---|---|
| committer | Christian Brauner <brauner@kernel.org> | 2026-01-29 17:26:30 +0100 |
| commit | b3c78bc53630d14a5770451ede3a30e7052f3b8b (patch) | |
| tree | abde4f6c6cd2525078b1c127f90a971747973d97 /include/linux | |
| parent | a39162f77f49b618df5a721a1e48d8b903280fbd (diff) | |
nfsd: do not allow exporting of special kernel filesystems
pidfs and nsfs recently gained support for encode/decode of file handles
via name_to_handle_at(2)/open_by_handle_at(2).
These special kernel filesystems have custom ->open() and ->permission()
export methods, which nfsd does not respect and it was never meant to be
used for exporting those filesystems by nfsd.
Therefore, do not allow nfsd to export filesystems with custom ->open()
or ->permission() methods.
Fixes: b3caba8f7a34a ("pidfs: implement file handle support")
Fixes: 5222470b2fbb3 ("nsfs: support file handles")
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Link: https://patch.msgid.link/20260129100212.49727-3-amir73il@gmail.com
Reviewed-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Christian Brauner <brauner@kernel.org>
Diffstat (limited to 'include/linux')
| -rw-r--r-- | include/linux/exportfs.h | 9 |
1 files changed, 9 insertions, 0 deletions
diff --git a/include/linux/exportfs.h b/include/linux/exportfs.h index 0660953c3fb7..8bcdba28b406 100644 --- a/include/linux/exportfs.h +++ b/include/linux/exportfs.h @@ -338,6 +338,15 @@ static inline bool exportfs_can_decode_fh(const struct export_operations *nop) return nop && nop->fh_to_dentry; } +static inline bool exportfs_may_export(const struct export_operations *nop) +{ + /* + * Do not allow nfs export for filesystems with custom ->open() or + * ->permission() ops, which nfsd does not respect (e.g. pidfs, nsfs). + */ + return exportfs_can_decode_fh(nop) && !nop->open && !nop->permission; +} + static inline bool exportfs_can_encode_fh(const struct export_operations *nop, int fh_flags) { |