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cred: Refcount the user_ns pointed to by the cred.
struct user_struct will shortly loose it's user_ns reference so make the cred user_ns reference a proper reference complete with reference counting. Acked-by: Serge Hallyn <serge.hallyn@canonical.com> Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
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@ -146,7 +146,7 @@ struct cred {
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void *security; /* subjective LSM security */
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#endif
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struct user_struct *user; /* real user ID subscription */
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struct user_namespace *user_ns; /* cached user->user_ns */
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struct user_namespace *user_ns; /* user_ns the caps and keyrings are relative to. */
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struct group_info *group_info; /* supplementary groups for euid/fsgid */
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struct rcu_head rcu; /* RCU deletion hook */
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};
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@ -148,6 +148,7 @@ static void put_cred_rcu(struct rcu_head *rcu)
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if (cred->group_info)
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put_group_info(cred->group_info);
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free_uid(cred->user);
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put_user_ns(cred->user_ns);
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kmem_cache_free(cred_jar, cred);
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}
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@ -303,6 +304,7 @@ struct cred *prepare_creds(void)
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set_cred_subscribers(new, 0);
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get_group_info(new->group_info);
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get_uid(new->user);
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get_user_ns(new->user_ns);
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#ifdef CONFIG_KEYS
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key_get(new->thread_keyring);
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@ -412,11 +414,6 @@ int copy_creds(struct task_struct *p, unsigned long clone_flags)
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goto error_put;
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}
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/* cache user_ns in cred. Doesn't need a refcount because it will
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* stay pinned by cred->user
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*/
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new->user_ns = new->user->user_ns;
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#ifdef CONFIG_KEYS
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/* new threads get their own thread keyrings if their parent already
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* had one */
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@ -676,6 +673,7 @@ struct cred *prepare_kernel_cred(struct task_struct *daemon)
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atomic_set(&new->usage, 1);
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set_cred_subscribers(new, 0);
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get_uid(new->user);
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get_user_ns(new->user_ns);
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get_group_info(new->group_info);
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#ifdef CONFIG_KEYS
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@ -24,7 +24,7 @@ static struct kmem_cache *user_ns_cachep __read_mostly;
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*/
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int create_user_ns(struct cred *new)
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{
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struct user_namespace *ns;
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struct user_namespace *ns, *parent_ns = new->user_ns;
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struct user_struct *root_user;
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int n;
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@ -57,8 +57,10 @@ int create_user_ns(struct cred *new)
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#endif
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/* tgcred will be cleared in our caller bc CLONE_THREAD won't be set */
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/* root_user holds a reference to ns, our reference can be dropped */
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put_user_ns(ns);
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/* Leave the reference to our user_ns with the new cred */
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new->user_ns = ns;
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put_user_ns(parent_ns);
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return 0;
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}
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@ -858,7 +858,7 @@ void key_replace_session_keyring(void)
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new-> sgid = old-> sgid;
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new->fsgid = old->fsgid;
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new->user = get_uid(old->user);
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new->user_ns = new->user_ns;
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new->user_ns = get_user_ns(new->user_ns);
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new->group_info = get_group_info(old->group_info);
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new->securebits = old->securebits;
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