Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit 0093ccb6 authored by Eric W. Biederman's avatar Eric W. Biederman
Browse files

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: default avatarSerge Hallyn <serge.hallyn@canonical.com>
Signed-off-by: default avatarEric W. Biederman <ebiederm@xmission.com>
parent c4a4d603

include/linux/cred.h

+1 −1
Original line number Diff line number Diff line
@@ -146,7 +146,7 @@ struct cred { 
	void		*security;	/* subjective LSM security */

#endif

	struct user_struct *user;	/* real user ID subscription */

	struct user_namespace *user_ns; /* cached user->user_ns */

	struct user_namespace *user_ns; /* user_ns the caps and keyrings are relative to. */

	struct group_info *group_info;	/* supplementary groups for euid/fsgid */

	struct rcu_head	rcu;		/* RCU deletion hook */

};

kernel/cred.c

+3 −5
Original line number Diff line number Diff line
@@ -148,6 +148,7 @@ static void put_cred_rcu(struct rcu_head *rcu) 
	if (cred->group_info)

		put_group_info(cred->group_info);

	free_uid(cred->user);

	put_user_ns(cred->user_ns);

	kmem_cache_free(cred_jar, cred);

}
@@ -303,6 +304,7 @@ struct cred *prepare_creds(void) 
	set_cred_subscribers(new, 0);

	get_group_info(new->group_info);

	get_uid(new->user);

	get_user_ns(new->user_ns);



#ifdef CONFIG_KEYS

	key_get(new->thread_keyring);
@@ -412,11 +414,6 @@ int copy_creds(struct task_struct *p, unsigned long clone_flags) 
			goto error_put;

	}



	/* cache user_ns in cred.  Doesn't need a refcount because it will

	 * stay pinned by cred->user

	 */

	new->user_ns = new->user->user_ns;



#ifdef CONFIG_KEYS

	/* new threads get their own thread keyrings if their parent already

	 * had one */
@@ -676,6 +673,7 @@ struct cred *prepare_kernel_cred(struct task_struct *daemon) 
	atomic_set(&new->usage, 1);

	set_cred_subscribers(new, 0);

	get_uid(new->user);

	get_user_ns(new->user_ns);

	get_group_info(new->group_info);



#ifdef CONFIG_KEYS

kernel/user_namespace.c

+5 −3
Original line number Diff line number Diff line
@@ -24,7 +24,7 @@ static struct kmem_cache *user_ns_cachep __read_mostly; 
 */

int create_user_ns(struct cred *new)

{

	struct user_namespace *ns;

	struct user_namespace *ns, *parent_ns = new->user_ns;

	struct user_struct *root_user;

	int n;
@@ -57,8 +57,10 @@ int create_user_ns(struct cred *new) 
#endif

	/* tgcred will be cleared in our caller bc CLONE_THREAD won't be set */



	/* root_user holds a reference to ns, our reference can be dropped */

	put_user_ns(ns);

	/* Leave the reference to our user_ns with the new cred */

	new->user_ns = ns;



	put_user_ns(parent_ns);



	return 0;

}

security/keys/process_keys.c

+1 −1
Original line number Diff line number Diff line
@@ -858,7 +858,7 @@ void key_replace_session_keyring(void) 
	new-> sgid	= old-> sgid;

	new->fsgid	= old->fsgid;

	new->user	= get_uid(old->user);

	new->user_ns	= new->user_ns;

	new->user_ns	= get_user_ns(new->user_ns);

	new->group_info	= get_group_info(old->group_info);



	new->securebits	= old->securebits;