summaryrefslogtreecommitdiffstats
path: root/fs/namespace.c
diff options
context:
space:
mode:
Diffstat (limited to 'fs/namespace.c')
-rw-r--r--fs/namespace.c118
1 files changed, 2 insertions, 116 deletions
diff --git a/fs/namespace.c b/fs/namespace.c
index 1ad4e5acef06..bc0f15257b49 100644
--- a/fs/namespace.c
+++ b/fs/namespace.c
@@ -75,22 +75,6 @@ static DECLARE_RWSEM(namespace_sem);
static HLIST_HEAD(unmounted); /* protected by namespace_sem */
static LIST_HEAD(ex_mountpoints); /* protected by namespace_sem */
-struct mnt_idmap {
- struct user_namespace *owner;
- refcount_t count;
-};
-
-/*
- * Carries the initial idmapping of 0:0:4294967295 which is an identity
- * mapping. This means that {g,u}id 0 is mapped to {g,u}id 0, {g,u}id 1 is
- * mapped to {g,u}id 1, [...], {g,u}id 1000 to {g,u}id 1000, [...].
- */
-struct mnt_idmap nop_mnt_idmap = {
- .owner = &init_user_ns,
- .count = REFCOUNT_INIT(1),
-};
-EXPORT_SYMBOL_GPL(nop_mnt_idmap);
-
struct mount_kattr {
unsigned int attr_set;
unsigned int attr_clr;
@@ -210,104 +194,6 @@ int mnt_get_count(struct mount *mnt)
#endif
}
-/**
- * mnt_idmap_owner - retrieve owner of the mount's idmapping
- * @idmap: mount idmapping
- *
- * This helper will go away once the conversion to use struct mnt_idmap
- * everywhere has finished at which point the helper will be unexported.
- *
- * Only code that needs to perform permission checks based on the owner of the
- * idmapping will get access to it. All other code will solely rely on
- * idmappings. This will get us type safety so it's impossible to conflate
- * filesystems idmappings with mount idmappings.
- *
- * Return: The owner of the idmapping.
- */
-struct user_namespace *mnt_idmap_owner(const struct mnt_idmap *idmap)
-{
- return idmap->owner;
-}
-EXPORT_SYMBOL_GPL(mnt_idmap_owner);
-
-/**
- * mnt_user_ns - retrieve owner of an idmapped mount
- * @mnt: the relevant vfsmount
- *
- * This helper will go away once the conversion to use struct mnt_idmap
- * everywhere has finished at which point the helper will be unexported.
- *
- * Only code that needs to perform permission checks based on the owner of the
- * idmapping will get access to it. All other code will solely rely on
- * idmappings. This will get us type safety so it's impossible to conflate
- * filesystems idmappings with mount idmappings.
- *
- * Return: The owner of the idmapped.
- */
-struct user_namespace *mnt_user_ns(const struct vfsmount *mnt)
-{
- struct mnt_idmap *idmap = mnt_idmap(mnt);
-
- /* Return the actual owner of the filesystem instead of the nop. */
- if (idmap == &nop_mnt_idmap &&
- !initial_idmapping(mnt->mnt_sb->s_user_ns))
- return mnt->mnt_sb->s_user_ns;
- return mnt_idmap_owner(idmap);
-}
-EXPORT_SYMBOL_GPL(mnt_user_ns);
-
-/**
- * alloc_mnt_idmap - allocate a new idmapping for the mount
- * @mnt_userns: owning userns of the idmapping
- *
- * Allocate a new struct mnt_idmap which carries the idmapping of the mount.
- *
- * Return: On success a new idmap, on error an error pointer is returned.
- */
-static struct mnt_idmap *alloc_mnt_idmap(struct user_namespace *mnt_userns)
-{
- struct mnt_idmap *idmap;
-
- idmap = kzalloc(sizeof(struct mnt_idmap), GFP_KERNEL_ACCOUNT);
- if (!idmap)
- return ERR_PTR(-ENOMEM);
-
- idmap->owner = get_user_ns(mnt_userns);
- refcount_set(&idmap->count, 1);
- return idmap;
-}
-
-/**
- * mnt_idmap_get - get a reference to an idmapping
- * @idmap: the idmap to bump the reference on
- *
- * If @idmap is not the @nop_mnt_idmap bump the reference count.
- *
- * Return: @idmap with reference count bumped if @not_mnt_idmap isn't passed.
- */
-static inline struct mnt_idmap *mnt_idmap_get(struct mnt_idmap *idmap)
-{
- if (idmap != &nop_mnt_idmap)
- refcount_inc(&idmap->count);
-
- return idmap;
-}
-
-/**
- * mnt_idmap_put - put a reference to an idmapping
- * @idmap: the idmap to put the reference on
- *
- * If this is a non-initial idmapping, put the reference count when a mount is
- * released and free it if we're the last user.
- */
-static inline void mnt_idmap_put(struct mnt_idmap *idmap)
-{
- if (idmap != &nop_mnt_idmap && refcount_dec_and_test(&idmap->count)) {
- put_user_ns(idmap->owner);
- kfree(idmap);
- }
-}
-
static struct mount *alloc_vfsmnt(const char *name)
{
struct mount *mnt = kmem_cache_zalloc(mnt_cache, GFP_KERNEL);
@@ -4105,7 +3991,7 @@ static int can_idmap_mount(const struct mount_kattr *kattr, struct mount *mnt)
* Creating an idmapped mount with the filesystem wide idmapping
* doesn't make sense so block that. We don't allow mushy semantics.
*/
- if (mnt_idmap_owner(kattr->mnt_idmap) == fs_userns)
+ if (!check_fsmapping(kattr->mnt_idmap, m->mnt_sb))
return -EINVAL;
/*
@@ -4351,7 +4237,7 @@ static int build_mount_idmapped(const struct mount_attr *attr, size_t usize,
* result.
*/
mnt_userns = container_of(ns, struct user_namespace, ns);
- if (initial_idmapping(mnt_userns)) {
+ if (mnt_userns == &init_user_ns) {
err = -EPERM;
goto out_fput;
}