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| author | Eric W. Biederman <ebiederm@xmission.com> | 2011-11-17 06:59:43 +0100 |
|---|---|---|
| committer | Eric W. Biederman <ebiederm@xmission.com> | 2012-04-08 01:55:52 +0200 |
| commit | aeb3ae9da9b50a386b22af786d19b623e8d9f0fa (patch) | |
| tree | 3db9772ea99c931914bec7ded51f896f1d2e24ec | |
| parent | cred: Refcount the user_ns pointed to by the cred. (diff) | |
| download | linux-aeb3ae9da9b50a386b22af786d19b623e8d9f0fa.tar.xz linux-aeb3ae9da9b50a386b22af786d19b623e8d9f0fa.zip | |
userns: Add an explicit reference to the parent user namespace
I am about to remove the struct user_namespace reference from struct user_struct.
So keep an explicit track of the parent user namespace.
Take advantage of this new reference and replace instances of user_ns->creator->user_ns
with user_ns->parent.
Acked-by: Serge Hallyn <serge.hallyn@canonical.com>
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
| -rw-r--r-- | include/linux/user_namespace.h | 1 | ||||
| -rw-r--r-- | kernel/user_namespace.c | 13 | ||||
| -rw-r--r-- | security/commoncap.c | 2 |
3 files changed, 8 insertions, 8 deletions
diff --git a/include/linux/user_namespace.h b/include/linux/user_namespace.h index faf467944baf..dc2d85a76376 100644 --- a/include/linux/user_namespace.h +++ b/include/linux/user_namespace.h @@ -12,6 +12,7 @@ struct user_namespace { struct kref kref; struct hlist_head uidhash_table[UIDHASH_SZ]; + struct user_namespace *parent; struct user_struct *creator; struct work_struct destroyer; }; diff --git a/kernel/user_namespace.c b/kernel/user_namespace.c index 58bb8781a778..c15e533d6bc5 100644 --- a/kernel/user_namespace.c +++ b/kernel/user_namespace.c @@ -45,6 +45,7 @@ int create_user_ns(struct cred *new) } /* set the new root user in the credentials under preparation */ + ns->parent = parent_ns; ns->creator = new->user; new->user = root_user; new->uid = new->euid = new->suid = new->fsuid = 0; @@ -60,8 +61,6 @@ int create_user_ns(struct cred *new) /* Leave the reference to our user_ns with the new cred */ new->user_ns = ns; - put_user_ns(parent_ns); - return 0; } @@ -72,10 +71,12 @@ int create_user_ns(struct cred *new) */ static void free_user_ns_work(struct work_struct *work) { - struct user_namespace *ns = + struct user_namespace *parent, *ns = container_of(work, struct user_namespace, destroyer); + parent = ns->parent; free_uid(ns->creator); kmem_cache_free(user_ns_cachep, ns); + put_user_ns(parent); } void free_user_ns(struct kref *kref) @@ -99,8 +100,7 @@ uid_t user_ns_map_uid(struct user_namespace *to, const struct cred *cred, uid_t /* Is cred->user the creator of the target user_ns * or the creator of one of it's parents? */ - for ( tmp = to; tmp != &init_user_ns; - tmp = tmp->creator->user_ns ) { + for ( tmp = to; tmp != &init_user_ns; tmp = tmp->parent ) { if (cred->user == tmp->creator) { return (uid_t)0; } @@ -120,8 +120,7 @@ gid_t user_ns_map_gid(struct user_namespace *to, const struct cred *cred, gid_t /* Is cred->user the creator of the target user_ns * or the creator of one of it's parents? */ - for ( tmp = to; tmp != &init_user_ns; - tmp = tmp->creator->user_ns ) { + for ( tmp = to; tmp != &init_user_ns; tmp = tmp->parent ) { if (cred->user == tmp->creator) { return (gid_t)0; } diff --git a/security/commoncap.c b/security/commoncap.c index 8b3e10e2eac7..435d074853f3 100644 --- a/security/commoncap.c +++ b/security/commoncap.c @@ -92,7 +92,7 @@ int cap_capable(const struct cred *cred, struct user_namespace *targ_ns, *If you have a capability in a parent user ns, then you have * it over all children user namespaces as well. */ - targ_ns = targ_ns->creator->user_ns; + targ_ns = targ_ns->parent; } /* We never get here */ |