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-rw-r--r--include/linux/cred.h17
-rw-r--r--kernel/cred.c127
-rw-r--r--security/keys/keyctl.c11
-rw-r--r--security/keys/process_keys.c66
-rw-r--r--security/keys/request_key.c10
5 files changed, 50 insertions, 181 deletions
diff --git a/include/linux/cred.h b/include/linux/cred.h
index ebbed2c..0142aac 100644
--- a/include/linux/cred.h
+++ b/include/linux/cred.h
@@ -77,21 +77,6 @@ extern int in_group_p(kgid_t);
extern int in_egroup_p(kgid_t);
/*
- * The common credentials for a thread group
- * - shared by CLONE_THREAD
- */
-#ifdef CONFIG_KEYS
-struct thread_group_cred {
- atomic_t usage;
- pid_t tgid; /* thread group process ID */
- spinlock_t lock;
- struct key __rcu *session_keyring; /* keyring inherited over fork */
- struct key *process_keyring; /* keyring private to this process */
- struct rcu_head rcu; /* RCU deletion hook */
-};
-#endif
-
-/*
* The security context of a task
*
* The parts of the context break down into two categories:
@@ -139,6 +124,8 @@ struct cred {
#ifdef CONFIG_KEYS
unsigned char jit_keyring; /* default keyring to attach requested
* keys to */
+ struct key __rcu *session_keyring; /* keyring inherited over fork */
+ struct key *process_keyring; /* keyring private to this process */
struct key *thread_keyring; /* keyring private to this thread */
struct key *request_key_auth; /* assumed request_key authority */
struct thread_group_cred *tgcred; /* thread-group shared credentials */
diff --git a/kernel/cred.c b/kernel/cred.c
index de728ac..3f7ad1e 100644
--- a/kernel/cred.c
+++ b/kernel/cred.c
@@ -30,17 +30,6 @@
static struct kmem_cache *cred_jar;
/*
- * The common credentials for the initial task's thread group
- */
-#ifdef CONFIG_KEYS
-static struct thread_group_cred init_tgcred = {
- .usage = ATOMIC_INIT(2),
- .tgid = 0,
- .lock = __SPIN_LOCK_UNLOCKED(init_cred.tgcred.lock),
-};
-#endif
-
-/*
* The initial credentials for the initial task
*/
struct cred init_cred = {
@@ -65,9 +54,6 @@ struct cred init_cred = {
.user = INIT_USER,
.user_ns = &init_user_ns,
.group_info = &init_groups,
-#ifdef CONFIG_KEYS
- .tgcred = &init_tgcred,
-#endif
};
static inline void set_cred_subscribers(struct cred *cred, int n)
@@ -96,36 +82,6 @@ static inline void alter_cred_subscribers(const struct cred *_cred, int n)
}
/*
- * Dispose of the shared task group credentials
- */
-#ifdef CONFIG_KEYS
-static void release_tgcred_rcu(struct rcu_head *rcu)
-{
- struct thread_group_cred *tgcred =
- container_of(rcu, struct thread_group_cred, rcu);
-
- BUG_ON(atomic_read(&tgcred->usage) != 0);
-
- key_put(tgcred->session_keyring);
- key_put(tgcred->process_keyring);
- kfree(tgcred);
-}
-#endif
-
-/*
- * Release a set of thread group credentials.
- */
-static void release_tgcred(struct cred *cred)
-{
-#ifdef CONFIG_KEYS
- struct thread_group_cred *tgcred = cred->tgcred;
-
- if (atomic_dec_and_test(&tgcred->usage))
- call_rcu(&tgcred->rcu, release_tgcred_rcu);
-#endif
-}
-
-/*
* The RCU callback to actually dispose of a set of credentials
*/
static void put_cred_rcu(struct rcu_head *rcu)
@@ -150,9 +106,10 @@ static void put_cred_rcu(struct rcu_head *rcu)
#endif
security_cred_free(cred);
+ key_put(cred->session_keyring);
+ key_put(cred->process_keyring);
key_put(cred->thread_keyring);
key_put(cred->request_key_auth);
- release_tgcred(cred);
if (cred->group_info)
put_group_info(cred->group_info);
free_uid(cred->user);
@@ -246,15 +203,6 @@ struct cred *cred_alloc_blank(void)
if (!new)
return NULL;
-#ifdef CONFIG_KEYS
- new->tgcred = kzalloc(sizeof(*new->tgcred), GFP_KERNEL);
- if (!new->tgcred) {
- kmem_cache_free(cred_jar, new);
- return NULL;
- }
- atomic_set(&new->tgcred->usage, 1);
-#endif
-
atomic_set(&new->usage, 1);
#ifdef CONFIG_DEBUG_CREDENTIALS
new->magic = CRED_MAGIC;
@@ -308,9 +256,10 @@ struct cred *prepare_creds(void)
get_user_ns(new->user_ns);
#ifdef CONFIG_KEYS
+ key_get(new->session_keyring);
+ key_get(new->process_keyring);
key_get(new->thread_keyring);
key_get(new->request_key_auth);
- atomic_inc(&new->tgcred->usage);
#endif
#ifdef CONFIG_SECURITY
@@ -334,39 +283,20 @@ EXPORT_SYMBOL(prepare_creds);
*/
struct cred *prepare_exec_creds(void)
{
- struct thread_group_cred *tgcred = NULL;
struct cred *new;
-#ifdef CONFIG_KEYS
- tgcred = kmalloc(sizeof(*tgcred), GFP_KERNEL);
- if (!tgcred)
- return NULL;
-#endif
-
new = prepare_creds();
- if (!new) {
- kfree(tgcred);
+ if (!new)
return new;
- }
#ifdef CONFIG_KEYS
/* newly exec'd tasks don't get a thread keyring */
key_put(new->thread_keyring);
new->thread_keyring = NULL;
- /* create a new per-thread-group creds for all this set of threads to
- * share */
- memcpy(tgcred, new->tgcred, sizeof(struct thread_group_cred));
-
- atomic_set(&tgcred->usage, 1);
- spin_lock_init(&tgcred->lock);
-
/* inherit the session keyring; new process keyring */
- key_get(tgcred->session_keyring);
- tgcred->process_keyring = NULL;
-
- release_tgcred(new);
- new->tgcred = tgcred;
+ key_put(new->process_keyring);
+ new->process_keyring = NULL;
#endif
return new;
@@ -383,9 +313,6 @@ struct cred *prepare_exec_creds(void)
*/
int copy_creds(struct task_struct *p, unsigned long clone_flags)
{
-#ifdef CONFIG_KEYS
- struct thread_group_cred *tgcred;
-#endif
struct cred *new;
int ret;
@@ -425,22 +352,12 @@ int copy_creds(struct task_struct *p, unsigned long clone_flags)
install_thread_keyring_to_cred(new);
}
- /* we share the process and session keyrings between all the threads in
- * a process - this is slightly icky as we violate COW credentials a
- * bit */
+ /* The process keyring is only shared between the threads in a process;
+ * anything outside of those threads doesn't inherit.
+ */
if (!(clone_flags & CLONE_THREAD)) {
- tgcred = kmalloc(sizeof(*tgcred), GFP_KERNEL);
- if (!tgcred) {
- ret = -ENOMEM;
- goto error_put;
- }
- atomic_set(&tgcred->usage, 1);
- spin_lock_init(&tgcred->lock);
- tgcred->process_keyring = NULL;
- tgcred->session_keyring = key_get(new->tgcred->session_keyring);
-
- release_tgcred(new);
- new->tgcred = tgcred;
+ key_put(new->process_keyring);
+ new->process_keyring = NULL;
}
#endif
@@ -643,9 +560,6 @@ void __init cred_init(void)
*/
struct cred *prepare_kernel_cred(struct task_struct *daemon)
{
-#ifdef CONFIG_KEYS
- struct thread_group_cred *tgcred;
-#endif
const struct cred *old;
struct cred *new;
@@ -653,14 +567,6 @@ struct cred *prepare_kernel_cred(struct task_struct *daemon)
if (!new)
return NULL;
-#ifdef CONFIG_KEYS
- tgcred = kmalloc(sizeof(*tgcred), GFP_KERNEL);
- if (!tgcred) {
- kmem_cache_free(cred_jar, new);
- return NULL;
- }
-#endif
-
kdebug("prepare_kernel_cred() alloc %p", new);
if (daemon)
@@ -678,13 +584,10 @@ struct cred *prepare_kernel_cred(struct task_struct *daemon)
get_group_info(new->group_info);
#ifdef CONFIG_KEYS
- atomic_set(&tgcred->usage, 1);
- spin_lock_init(&tgcred->lock);
- tgcred->process_keyring = NULL;
- tgcred->session_keyring = NULL;
- new->tgcred = tgcred;
- new->request_key_auth = NULL;
+ new->session_keyring = NULL;
+ new->process_keyring = NULL;
new->thread_keyring = NULL;
+ new->request_key_auth = NULL;
new->jit_keyring = KEY_REQKEY_DEFL_THREAD_KEYRING;
#endif
diff --git a/security/keys/keyctl.c b/security/keys/keyctl.c
index a0d373f..65b38417 100644
--- a/security/keys/keyctl.c
+++ b/security/keys/keyctl.c
@@ -1475,7 +1475,8 @@ long keyctl_session_to_parent(void)
goto error_keyring;
newwork = &cred->rcu;
- cred->tgcred->session_keyring = key_ref_to_ptr(keyring_r);
+ cred->session_keyring = key_ref_to_ptr(keyring_r);
+ keyring_r = NULL;
init_task_work(newwork, key_change_session_keyring);
me = current;
@@ -1500,7 +1501,7 @@ long keyctl_session_to_parent(void)
mycred = current_cred();
pcred = __task_cred(parent);
if (mycred == pcred ||
- mycred->tgcred->session_keyring == pcred->tgcred->session_keyring) {
+ mycred->session_keyring == pcred->session_keyring) {
ret = 0;
goto unlock;
}
@@ -1516,9 +1517,9 @@ long keyctl_session_to_parent(void)
goto unlock;
/* the keyrings must have the same UID */
- if ((pcred->tgcred->session_keyring &&
- pcred->tgcred->session_keyring->uid != mycred->euid) ||
- mycred->tgcred->session_keyring->uid != mycred->euid)
+ if ((pcred->session_keyring &&
+ pcred->session_keyring->uid != mycred->euid) ||
+ mycred->session_keyring->uid != mycred->euid)
goto unlock;
/* cancel an already pending keyring replacement */
diff --git a/security/keys/process_keys.c b/security/keys/process_keys.c
index 178b8c3..9de5dc5 100644
--- a/security/keys/process_keys.c
+++ b/security/keys/process_keys.c
@@ -169,9 +169,8 @@ static int install_thread_keyring(void)
int install_process_keyring_to_cred(struct cred *new)
{
struct key *keyring;
- int ret;
- if (new->tgcred->process_keyring)
+ if (new->process_keyring)
return -EEXIST;
keyring = keyring_alloc("_pid", new->uid, new->gid,
@@ -179,17 +178,8 @@ int install_process_keyring_to_cred(struct cred *new)
if (IS_ERR(keyring))
return PTR_ERR(keyring);
- spin_lock_irq(&new->tgcred->lock);
- if (!new->tgcred->process_keyring) {
- new->tgcred->process_keyring = keyring;
- keyring = NULL;
- ret = 0;
- } else {
- ret = -EEXIST;
- }
- spin_unlock_irq(&new->tgcred->lock);
- key_put(keyring);
- return ret;
+ new->process_keyring = keyring;
+ return 0;
}
/*
@@ -230,7 +220,7 @@ int install_session_keyring_to_cred(struct cred *cred, struct key *keyring)
/* create an empty session keyring */
if (!keyring) {
flags = KEY_ALLOC_QUOTA_OVERRUN;
- if (cred->tgcred->session_keyring)
+ if (cred->session_keyring)
flags = KEY_ALLOC_IN_QUOTA;
keyring = keyring_alloc("_ses", cred->uid, cred->gid,
@@ -242,17 +232,11 @@ int install_session_keyring_to_cred(struct cred *cred, struct key *keyring)
}
/* install the keyring */
- spin_lock_irq(&cred->tgcred->lock);
- old = cred->tgcred->session_keyring;
- rcu_assign_pointer(cred->tgcred->session_keyring, keyring);
- spin_unlock_irq(&cred->tgcred->lock);
-
- /* we're using RCU on the pointer, but there's no point synchronising
- * on it if it didn't previously point to anything */
- if (old) {
- synchronize_rcu();
+ old = cred->session_keyring;
+ rcu_assign_pointer(cred->session_keyring, keyring);
+
+ if (old)
key_put(old);
- }
return 0;
}
@@ -367,9 +351,9 @@ key_ref_t search_my_process_keyrings(struct key_type *type,
}
/* search the process keyring second */
- if (cred->tgcred->process_keyring) {
+ if (cred->process_keyring) {
key_ref = keyring_search_aux(
- make_key_ref(cred->tgcred->process_keyring, 1),
+ make_key_ref(cred->process_keyring, 1),
cred, type, description, match, no_state_check);
if (!IS_ERR(key_ref))
goto found;
@@ -388,12 +372,10 @@ key_ref_t search_my_process_keyrings(struct key_type *type,
}
/* search the session keyring */
- if (cred->tgcred->session_keyring) {
+ if (cred->session_keyring) {
rcu_read_lock();
key_ref = keyring_search_aux(
- make_key_ref(rcu_dereference(
- cred->tgcred->session_keyring),
- 1),
+ make_key_ref(rcu_dereference(cred->session_keyring), 1),
cred, type, description, match, no_state_check);
rcu_read_unlock();
@@ -563,7 +545,7 @@ try_again:
break;
case KEY_SPEC_PROCESS_KEYRING:
- if (!cred->tgcred->process_keyring) {
+ if (!cred->process_keyring) {
if (!(lflags & KEY_LOOKUP_CREATE))
goto error;
@@ -575,13 +557,13 @@ try_again:
goto reget_creds;
}
- key = cred->tgcred->process_keyring;
+ key = cred->process_keyring;
atomic_inc(&key->usage);
key_ref = make_key_ref(key, 1);
break;
case KEY_SPEC_SESSION_KEYRING:
- if (!cred->tgcred->session_keyring) {
+ if (!cred->session_keyring) {
/* always install a session keyring upon access if one
* doesn't exist yet */
ret = install_user_keyrings();
@@ -596,7 +578,7 @@ try_again:
if (ret < 0)
goto error;
goto reget_creds;
- } else if (cred->tgcred->session_keyring ==
+ } else if (cred->session_keyring ==
cred->user->session_keyring &&
lflags & KEY_LOOKUP_CREATE) {
ret = join_session_keyring(NULL);
@@ -606,7 +588,7 @@ try_again:
}
rcu_read_lock();
- key = rcu_dereference(cred->tgcred->session_keyring);
+ key = rcu_dereference(cred->session_keyring);
atomic_inc(&key->usage);
rcu_read_unlock();
key_ref = make_key_ref(key, 1);
@@ -766,12 +748,6 @@ long join_session_keyring(const char *name)
struct key *keyring;
long ret, serial;
- /* only permit this if there's a single thread in the thread group -
- * this avoids us having to adjust the creds on all threads and risking
- * ENOMEM */
- if (!current_is_single_threaded())
- return -EMLINK;
-
new = prepare_creds();
if (!new)
return -ENOMEM;
@@ -783,7 +759,7 @@ long join_session_keyring(const char *name)
if (ret < 0)
goto error;
- serial = new->tgcred->session_keyring->serial;
+ serial = new->session_keyring->serial;
ret = commit_creds(new);
if (ret == 0)
ret = serial;
@@ -806,6 +782,9 @@ long join_session_keyring(const char *name)
} else if (IS_ERR(keyring)) {
ret = PTR_ERR(keyring);
goto error2;
+ } else if (keyring == new->session_keyring) {
+ ret = 0;
+ goto error2;
}
/* we've got a keyring - now to install it */
@@ -862,8 +841,7 @@ void key_change_session_keyring(struct callback_head *twork)
new->jit_keyring = old->jit_keyring;
new->thread_keyring = key_get(old->thread_keyring);
- new->tgcred->tgid = old->tgcred->tgid;
- new->tgcred->process_keyring = key_get(old->tgcred->process_keyring);
+ new->process_keyring = key_get(old->process_keyring);
security_transfer_creds(new, old);
diff --git a/security/keys/request_key.c b/security/keys/request_key.c
index 000e750..275c4f9 100644
--- a/security/keys/request_key.c
+++ b/security/keys/request_key.c
@@ -150,12 +150,12 @@ static int call_sbin_request_key(struct key_construction *cons,
cred->thread_keyring ? cred->thread_keyring->serial : 0);
prkey = 0;
- if (cred->tgcred->process_keyring)
- prkey = cred->tgcred->process_keyring->serial;
+ if (cred->process_keyring)
+ prkey = cred->process_keyring->serial;
sprintf(keyring_str[1], "%d", prkey);
rcu_read_lock();
- session = rcu_dereference(cred->tgcred->session_keyring);
+ session = rcu_dereference(cred->session_keyring);
if (!session)
session = cred->user->session_keyring;
sskey = session->serial;
@@ -297,14 +297,14 @@ static void construct_get_dest_keyring(struct key **_dest_keyring)
break;
case KEY_REQKEY_DEFL_PROCESS_KEYRING:
- dest_keyring = key_get(cred->tgcred->process_keyring);
+ dest_keyring = key_get(cred->process_keyring);
if (dest_keyring)
break;
case KEY_REQKEY_DEFL_SESSION_KEYRING:
rcu_read_lock();
dest_keyring = key_get(
- rcu_dereference(cred->tgcred->session_keyring));
+ rcu_dereference(cred->session_keyring));
rcu_read_unlock();
if (dest_keyring)
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