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| author | Alexander Mikhalitsyn <aleksandr.mikhalitsyn@canonical.com> | 2024-09-06 16:34:52 +0200 |
|---|---|---|
| committer | Miklos Szeredi <mszeredi@redhat.com> | 2024-09-23 11:07:55 +0200 |
| commit | ffcdc4c628e1a30489da10dd78358e89c823b341 (patch) | |
| tree | 4a613054af1d41c639012c66c57ec9751f92142c /fs/mnt_idmapping.c | |
| parent | 0c6793823d2b0eb079f4c6f54d9cdf6b2beec9d8 (diff) | |
| download | lwn-ffcdc4c628e1a30489da10dd78358e89c823b341.tar.gz lwn-ffcdc4c628e1a30489da10dd78358e89c823b341.zip | |
fs/mnt_idmapping: introduce an invalid_mnt_idmap
Link: https://lore.kernel.org/linux-fsdevel/20240904-baugrube-erhoben-b3c1c49a2645@brauner/
Suggested-by: Christian Brauner <brauner@kernel.org>
Signed-off-by: Alexander Mikhalitsyn <aleksandr.mikhalitsyn@canonical.com>
Reviewed-by: Christian Brauner <brauner@kernel.org>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
Diffstat (limited to 'fs/mnt_idmapping.c')
| -rw-r--r-- | fs/mnt_idmapping.c | 22 |
1 files changed, 20 insertions, 2 deletions
diff --git a/fs/mnt_idmapping.c b/fs/mnt_idmapping.c index 3c60f1eaca61..cbca6500848e 100644 --- a/fs/mnt_idmapping.c +++ b/fs/mnt_idmapping.c @@ -32,6 +32,15 @@ struct mnt_idmap nop_mnt_idmap = { }; EXPORT_SYMBOL_GPL(nop_mnt_idmap); +/* + * Carries the invalid idmapping of a full 0-4294967295 {g,u}id range. + * This means that all {g,u}ids are mapped to INVALID_VFS{G,U}ID. + */ +struct mnt_idmap invalid_mnt_idmap = { + .count = REFCOUNT_INIT(1), +}; +EXPORT_SYMBOL_GPL(invalid_mnt_idmap); + /** * initial_idmapping - check whether this is the initial mapping * @ns: idmapping to check @@ -75,6 +84,8 @@ vfsuid_t make_vfsuid(struct mnt_idmap *idmap, if (idmap == &nop_mnt_idmap) return VFSUIDT_INIT(kuid); + if (idmap == &invalid_mnt_idmap) + return INVALID_VFSUID; if (initial_idmapping(fs_userns)) uid = __kuid_val(kuid); else @@ -112,6 +123,8 @@ vfsgid_t make_vfsgid(struct mnt_idmap *idmap, if (idmap == &nop_mnt_idmap) return VFSGIDT_INIT(kgid); + if (idmap == &invalid_mnt_idmap) + return INVALID_VFSGID; if (initial_idmapping(fs_userns)) gid = __kgid_val(kgid); else @@ -140,6 +153,8 @@ kuid_t from_vfsuid(struct mnt_idmap *idmap, if (idmap == &nop_mnt_idmap) return AS_KUIDT(vfsuid); + if (idmap == &invalid_mnt_idmap) + return INVALID_UID; uid = map_id_up(&idmap->uid_map, __vfsuid_val(vfsuid)); if (uid == (uid_t)-1) return INVALID_UID; @@ -167,6 +182,8 @@ kgid_t from_vfsgid(struct mnt_idmap *idmap, if (idmap == &nop_mnt_idmap) return AS_KGIDT(vfsgid); + if (idmap == &invalid_mnt_idmap) + return INVALID_GID; gid = map_id_up(&idmap->gid_map, __vfsgid_val(vfsgid)); if (gid == (gid_t)-1) return INVALID_GID; @@ -296,7 +313,7 @@ struct mnt_idmap *alloc_mnt_idmap(struct user_namespace *mnt_userns) */ struct mnt_idmap *mnt_idmap_get(struct mnt_idmap *idmap) { - if (idmap != &nop_mnt_idmap) + if (idmap != &nop_mnt_idmap && idmap != &invalid_mnt_idmap) refcount_inc(&idmap->count); return idmap; @@ -312,7 +329,8 @@ EXPORT_SYMBOL_GPL(mnt_idmap_get); */ void mnt_idmap_put(struct mnt_idmap *idmap) { - if (idmap != &nop_mnt_idmap && refcount_dec_and_test(&idmap->count)) + if (idmap != &nop_mnt_idmap && idmap != &invalid_mnt_idmap && + refcount_dec_and_test(&idmap->count)) free_mnt_idmap(idmap); } EXPORT_SYMBOL_GPL(mnt_idmap_put); |