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keys: distinguish per-uid keys in different namespaces 

per-uid keys were looked by uid only.  Use the user namespace
to distinguish the same uid in different namespaces.

This does not address key_permission.  So a task can for instance
try to join a keyring owned by the same uid in another namespace.
That will be handled by a separate patch.

Signed-off-by: Serge E. Hallyn <serue@us.ibm.com>
Acked-by: David Howells <dhowells@redhat.com>
Signed-off-by: James Morris <jmorris@namei.org>
This commit is contained in:
Serge E. Hallyn 2009-02-26 18:27:38 -06:00 committed by James Morris
parent be38e0fd5f
commit 1d1e97562e
6 changed files with 17 additions and 6 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

2
kernel/user.c
View File

@ -20,7 +20,7 @@
struct user_namespace init_user_ns = {
.kref = {
.refcount = ATOMIC_INIT(1),
.refcount = ATOMIC_INIT(2),
},
.creator = &root_user,
};

4
security/keys/internal.h
View File

@ -53,6 +53,7 @@ struct key_user {
atomic_t nkeys; /* number of keys */
atomic_t nikeys; /* number of instantiated keys */
uid_t uid;
struct user_namespace *user_ns;
int qnkeys; /* number of keys allocated to this user */
int qnbytes; /* number of bytes allocated to this user */
};
@ -61,7 +62,8 @@ extern struct rb_root key_user_tree;
extern spinlock_t key_user_lock;
extern struct key_user root_key_user;
extern struct key_user *key_user_lookup(uid_t uid);
extern struct key_user *key_user_lookup(uid_t uid,
struct user_namespace *user_ns);
extern void key_user_put(struct key_user *user);
/*

11
security/keys/key.c
View File

@ -18,6 +18,7 @@
#include <linux/workqueue.h>
#include <linux/random.h>
#include <linux/err.h>
#include <linux/user_namespace.h>
#include "internal.h"
static struct kmem_cache *key_jar;
@ -60,7 +61,7 @@ void __key_check(const struct key *key)
* get the key quota record for a user, allocating a new record if one doesn't
* already exist
*/
struct key_user *key_user_lookup(uid_t uid)
struct key_user *key_user_lookup(uid_t uid, struct user_namespace *user_ns)
{
struct key_user *candidate = NULL, *user;
struct rb_node *parent = NULL;
@ -79,6 +80,10 @@ struct key_user *key_user_lookup(uid_t uid)
p = &(*p)->rb_left;
else if (uid > user->uid)
p = &(*p)->rb_right;
else if (user_ns < user->user_ns)
p = &(*p)->rb_left;
else if (user_ns > user->user_ns)
p = &(*p)->rb_right;
else
goto found;
}
@ -106,6 +111,7 @@ struct key_user *key_user_lookup(uid_t uid)
atomic_set(&candidate->nkeys, 0);
atomic_set(&candidate->nikeys, 0);
candidate->uid = uid;
candidate->user_ns = get_user_ns(user_ns);
candidate->qnkeys = 0;
candidate->qnbytes = 0;
spin_lock_init(&candidate->lock);
@ -136,6 +142,7 @@ void key_user_put(struct key_user *user)
if (atomic_dec_and_lock(&user->usage, &key_user_lock)) {
rb_erase(&user->node, &key_user_tree);
spin_unlock(&key_user_lock);
put_user_ns(user->user_ns);
kfree(user);
}
@ -234,7 +241,7 @@ struct key *key_alloc(struct key_type *type, const char *desc,
quotalen = desclen + type->def_datalen;
/* get hold of the key tracking for this user */
user = key_user_lookup(uid);
user = key_user_lookup(uid, cred->user->user_ns);
if (!user)
goto no_memory_1;

2
security/keys/keyctl.c
View File

@ -726,7 +726,7 @@ long keyctl_chown_key(key_serial_t id, uid_t uid, gid_t gid)
/* change the UID */
if (uid != (uid_t) -1 && uid != key->uid) {
ret = -ENOMEM;
newowner = key_user_lookup(uid);
newowner = key_user_lookup(uid, current_user_ns());
if (!newowner)
goto error_put;

2
security/keys/process_keys.c
View File

@ -17,6 +17,7 @@
#include <linux/fs.h>
#include <linux/err.h>
#include <linux/mutex.h>
#include <linux/user_namespace.h>
#include <asm/uaccess.h>
#include "internal.h"
@ -34,6 +35,7 @@ struct key_user root_key_user = {
.nkeys = ATOMIC_INIT(2),
.nikeys = ATOMIC_INIT(2),
.uid = 0,
.user_ns = &init_user_ns,
};
/*****************************************************************************/

2
security/keys/request_key.c
View File

@ -365,7 +365,7 @@ static struct key *construct_key_and_link(struct key_type *type,
kenter("");
user = key_user_lookup(current_fsuid());
user = key_user_lookup(current_fsuid(), current_user_ns());
if (!user)
return ERR_PTR(-ENOMEM);