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Subject[PATCH 1/4] 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>
---
kernel/user.c | 2 +-
security/keys/internal.h | 4 +++-
security/keys/key.c | 11 +++++++++--
security/keys/keyctl.c | 2 +-
security/keys/process_keys.c | 2 ++
security/keys/request_key.c | 2 +-
6 files changed, 17 insertions(+), 6 deletions(-)
diff --git a/kernel/user.c b/kernel/user.c
index 6608a3d..fe326a6 100644
--- a/kernel/user.c
+++ b/kernel/user.c
@@ -20,7 +20,7 @@

struct user_namespace init_user_ns = {
.kref = {
- .refcount = ATOMIC_INIT(1),
+ .refcount = ATOMIC_INIT(2),
},
.creator = &root_user,
};
diff --git a/security/keys/internal.h b/security/keys/internal.h
index 81932ab..9fb679c 100644
--- a/security/keys/internal.h
+++ b/security/keys/internal.h
@@ -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);

/*
diff --git a/security/keys/key.c b/security/keys/key.c
index f76c8a5..4a1297d 100644
--- a/security/keys/key.c
+++ b/security/keys/key.c
@@ -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;

diff --git a/security/keys/keyctl.c b/security/keys/keyctl.c
index 7c72baa..db4c029 100644
--- a/security/keys/keyctl.c
+++ b/security/keys/keyctl.c
@@ -725,7 +725,7 @@ 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;

diff --git a/security/keys/process_keys.c b/security/keys/process_keys.c
index 2f5d89e..276d278 100644
--- a/security/keys/process_keys.c
+++ b/security/keys/process_keys.c
@@ -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,
};

/*****************************************************************************/
diff --git a/security/keys/request_key.c b/security/keys/request_key.c
index 0e04f72..22a3158 100644
--- a/security/keys/request_key.c
+++ b/security/keys/request_key.c
@@ -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);

--
1.5.4.3


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