/*
* get the authorisation key for instantiation of a specific key if attached to
* the current process's keyrings
* - this key is inserted into a keyring and that is set as /sbin/request-key's
* session keyring
* - a target_id of zero specifies any valid token
*/
struct key *key_get_instantiation_authkey(key_serial_t target_id)
{
struct key *authkey;
key_ref_t authkey_ref;
authkey_ref = search_process_keyrings(
&key_type_request_key_auth,
(void *) (unsigned long) target_id,
key_get_instantiation_authkey_match,
current);
if (IS_ERR(authkey_ref)) {
authkey = ERR_PTR(PTR_ERR(authkey_ref));
goto error;
}
authkey = key_ref_to_ptr(authkey_ref);
if (test_bit(KEY_FLAG_REVOKED, &authkey->flags)) {
key_put(authkey);
authkey = ERR_PTR(-EKEYREVOKED);
}
error:
return authkey;
} /* end key_get_instantiation_authkey() */
/*
* allocate a new key in under-construction state and attempt to link it in to
* the requested place
* - may return a key that's already under construction instead
*/
static int construct_alloc_key(struct key_type *type,
const char *description,
struct key *dest_keyring,
unsigned long flags,
struct key_user *user,
struct key **_key)
{
const struct cred *cred = current_cred();
struct key *key;
key_ref_t key_ref;
kenter("%s,%s,,,", type->name, description);
mutex_lock(&user->cons_lock);
key = key_alloc(type, description, cred->fsuid, cred->fsgid, cred,
KEY_POS_ALL, flags);
if (IS_ERR(key))
goto alloc_failed;
set_bit(KEY_FLAG_USER_CONSTRUCT, &key->flags);
down_write(&dest_keyring->sem);
/* attach the key to the destination keyring under lock, but we do need
* to do another check just in case someone beat us to it whilst we
* waited for locks */
mutex_lock(&key_construction_mutex);
key_ref = search_process_keyrings(type, description, type->match, cred);
if (!IS_ERR(key_ref))
goto key_already_present;
__key_link(dest_keyring, key);
mutex_unlock(&key_construction_mutex);
up_write(&dest_keyring->sem);
mutex_unlock(&user->cons_lock);
*_key = key;
kleave(" = 0 [%d]", key_serial(key));
return 0;
key_already_present:
mutex_unlock(&key_construction_mutex);
if (dest_keyring)
up_write(&dest_keyring->sem);
mutex_unlock(&user->cons_lock);
key_put(key);
*_key = key = key_ref_to_ptr(key_ref);
kleave(" = -EINPROGRESS [%d]", key_serial(key));
return -EINPROGRESS;
alloc_failed:
mutex_unlock(&user->cons_lock);
*_key = NULL;
kleave(" = %ld", PTR_ERR(key));
return PTR_ERR(key);
}
/**
* request_key_and_link - Request a key and cache it in a keyring.
* @type: The type of key we want.
* @description: The searchable description of the key.
* @callout_info: The data to pass to the instantiation upcall (or NULL).
* @callout_len: The length of callout_info.
* @aux: Auxiliary data for the upcall.
* @dest_keyring: Where to cache the key.
* @flags: Flags to key_alloc().
*
* A key matching the specified criteria is searched for in the process's
* keyrings and returned with its usage count incremented if found. Otherwise,
* if callout_info is not NULL, a key will be allocated and some service
* (probably in userspace) will be asked to instantiate it.
*
* If successfully found or created, the key will be linked to the destination
* keyring if one is provided.
*
* Returns a pointer to the key if successful; -EACCES, -ENOKEY, -EKEYREVOKED
* or -EKEYEXPIRED if an inaccessible, negative, revoked or expired key was
* found; -ENOKEY if no key was found and no @callout_info was given; -EDQUOT
* if insufficient key quota was available to create a new key; or -ENOMEM if
* insufficient memory was available.
*
* If the returned key was created, then it may still be under construction,
* and wait_for_key_construction() should be used to wait for that to complete.
*/
struct key *request_key_and_link(struct key_type *type,
const char *description,
const void *callout_info,
size_t callout_len,
void *aux,
struct key *dest_keyring,
unsigned long flags)
{
const struct cred *cred = current_cred();
struct key *key;
key_ref_t key_ref;
int ret;
kenter("%s,%s,%p,%zu,%p,%p,%lx",
type->name, description, callout_info, callout_len, aux,
dest_keyring, flags);
/* search all the process keyrings for a key */
key_ref = search_process_keyrings(type, description, type->match, cred);
if (!IS_ERR(key_ref)) {
key = key_ref_to_ptr(key_ref);
if (dest_keyring) {
construct_get_dest_keyring(&dest_keyring);
ret = key_link(dest_keyring, key);
key_put(dest_keyring);
if (ret < 0) {
key_put(key);
key = ERR_PTR(ret);
goto error;
}
}
} else if (PTR_ERR(key_ref) != -EAGAIN) {
key = ERR_CAST(key_ref);
} else {
/* the search failed, but the keyrings were searchable, so we
* should consult userspace if we can */
key = ERR_PTR(-ENOKEY);
if (!callout_info)
goto error;
key = construct_key_and_link(type, description, callout_info,
callout_len, aux, dest_keyring,
flags);
}
error:
kleave(" = %p", key);
return key;
}
/*
* request a key
* - search the process's keyrings
* - check the list of keys being created or updated
* - call out to userspace for a key if supplementary info was provided
* - cache the key in an appropriate keyring
*/
struct key *request_key_and_link(struct key_type *type,
const char *description,
const char *callout_info,
void *aux,
struct key *dest_keyring,
unsigned long flags)
{
struct key *key;
key_ref_t key_ref;
kenter("%s,%s,%s,%p,%p,%lx",
type->name, description, callout_info, aux,
dest_keyring, flags);
/* search all the process keyrings for a key */
key_ref = search_process_keyrings(type, description, type->match,
current);
if (!IS_ERR(key_ref)) {
key = key_ref_to_ptr(key_ref);
} else if (PTR_ERR(key_ref) != -EAGAIN) {
key = ERR_PTR(PTR_ERR(key_ref));
} else {
/* the search failed, but the keyrings were searchable, so we
* should consult userspace if we can */
key = ERR_PTR(-ENOKEY);
if (!callout_info)
goto error;
key = construct_key_and_link(type, description, callout_info,
aux, dest_keyring, flags);
}
error:
kleave(" = %p", key);
return key;
}
/*
* Allocate a new key in under-construction state and attempt to link it in to
* the requested keyring.
*
* May return a key that's already under construction instead if there was a
* race between two thread calling request_key().
*/
static int construct_alloc_key(struct key_type *type,
const char *description,
struct key *dest_keyring,
unsigned long flags,
struct key_user *user,
struct key **_key)
{
const struct cred *cred = current_cred();
unsigned long prealloc;
struct key *key;
key_ref_t key_ref;
int ret;
kenter("%s,%s,,,", type->name, description);
*_key = NULL;
mutex_lock(&user->cons_lock);
key = key_alloc(type, description, cred->fsuid, cred->fsgid, cred,
KEY_POS_ALL, flags);
if (IS_ERR(key))
goto alloc_failed;
set_bit(KEY_FLAG_USER_CONSTRUCT, &key->flags);
if (dest_keyring) {
ret = __key_link_begin(dest_keyring, type, description,
&prealloc);
if (ret < 0)
goto link_prealloc_failed;
}
/* attach the key to the destination keyring under lock, but we do need
* to do another check just in case someone beat us to it whilst we
* waited for locks */
mutex_lock(&key_construction_mutex);
key_ref = search_process_keyrings(type, description, type->match, cred);
if (!IS_ERR(key_ref))
goto key_already_present;
if (dest_keyring)
__key_link(dest_keyring, key, &prealloc);
mutex_unlock(&key_construction_mutex);
if (dest_keyring)
__key_link_end(dest_keyring, type, prealloc);
mutex_unlock(&user->cons_lock);
*_key = key;
kleave(" = 0 [%d]", key_serial(key));
return 0;
/* the key is now present - we tell the caller that we found it by
* returning -EINPROGRESS */
key_already_present:
key_put(key);
mutex_unlock(&key_construction_mutex);
key = key_ref_to_ptr(key_ref);
if (dest_keyring) {
ret = __key_link_check_live_key(dest_keyring, key);
if (ret == 0)
__key_link(dest_keyring, key, &prealloc);
__key_link_end(dest_keyring, type, prealloc);
if (ret < 0)
goto link_check_failed;
}
mutex_unlock(&user->cons_lock);
*_key = key;
kleave(" = -EINPROGRESS [%d]", key_serial(key));
return -EINPROGRESS;
link_check_failed:
mutex_unlock(&user->cons_lock);
key_put(key);
kleave(" = %d [linkcheck]", ret);
return ret;
link_prealloc_failed:
mutex_unlock(&user->cons_lock);
kleave(" = %d [prelink]", ret);
return ret;
alloc_failed:
mutex_unlock(&user->cons_lock);
kleave(" = %ld", PTR_ERR(key));
return PTR_ERR(key);
}
/**
* request_key_and_link - Request a key and cache it in a keyring.
* @type: The type of key we want.
* @description: The searchable description of the key.
* @callout_info: The data to pass to the instantiation upcall (or NULL).
* @callout_len: The length of callout_info.
* @aux: Auxiliary data for the upcall.
* @dest_keyring: Where to cache the key.
* @flags: Flags to key_alloc().
*
* A key matching the specified criteria is searched for in the process's
* keyrings and returned with its usage count incremented if found. Otherwise,
* if callout_info is not NULL, a key will be allocated and some service
* (probably in userspace) will be asked to instantiate it.
*
* If successfully found or created, the key will be linked to the destination
* keyring if one is provided.
*
* Returns a pointer to the key if successful; -EACCES, -ENOKEY, -EKEYREVOKED
* or -EKEYEXPIRED if an inaccessible, negative, revoked or expired key was
* found; -ENOKEY if no key was found and no @callout_info was given; -EDQUOT
* if insufficient key quota was available to create a new key; or -ENOMEM if
* insufficient memory was available.
*
* If the returned key was created, then it may still be under construction,
* and wait_for_key_construction() should be used to wait for that to complete.
*/
struct key *request_key_and_link(struct key_type *type,
const char *description,
const void *callout_info,
size_t callout_len,
void *aux,
struct key *dest_keyring,
unsigned long flags)
{
struct keyring_search_context ctx = {
.index_key.type = type,
.index_key.description = description,
.cred = current_cred(),
.match_data.cmp = key_default_cmp,
.match_data.raw_data = description,
.match_data.lookup_type = KEYRING_SEARCH_LOOKUP_DIRECT,
.flags = (KEYRING_SEARCH_DO_STATE_CHECK |
KEYRING_SEARCH_SKIP_EXPIRED),
};
struct key *key;
key_ref_t key_ref;
int ret;
kenter("%s,%s,%p,%zu,%p,%p,%lx",
ctx.index_key.type->name, ctx.index_key.description,
callout_info, callout_len, aux, dest_keyring, flags);
if (type->match_preparse) {
ret = type->match_preparse(&ctx.match_data);
if (ret < 0) {
key = ERR_PTR(ret);
goto error;
}
}
/* search all the process keyrings for a key */
key_ref = search_process_keyrings(&ctx);
if (!IS_ERR(key_ref)) {
key = key_ref_to_ptr(key_ref);
if (dest_keyring) {
construct_get_dest_keyring(&dest_keyring);
ret = key_link(dest_keyring, key);
key_put(dest_keyring);
if (ret < 0) {
key_put(key);
key = ERR_PTR(ret);
goto error_free;
}
}
} else if (PTR_ERR(key_ref) != -EAGAIN) {
key = ERR_CAST(key_ref);
} else {
/* the search failed, but the keyrings were searchable, so we
* should consult userspace if we can */
key = ERR_PTR(-ENOKEY);
if (!callout_info)
goto error_free;
key = construct_key_and_link(&ctx, callout_info, callout_len,
aux, dest_keyring, flags);
}
error_free:
if (type->match_free)
type->match_free(&ctx.match_data);
error:
kleave(" = %p", key);
return key;
}
/**
* wait_for_key_construction - Wait for construction of a key to complete
* @key: The key being waited for.
* @intr: Whether to wait interruptibly.
*
* Wait for a key to finish being constructed.
*
* Returns 0 if successful; -ERESTARTSYS if the wait was interrupted; -ENOKEY
* if the key was negated; or -EKEYREVOKED or -EKEYEXPIRED if the key was
* revoked or expired.
*/
int wait_for_key_construction(struct key *key, bool intr)
{
int ret;
ret = wait_on_bit(&key->flags, KEY_FLAG_USER_CONSTRUCT,
intr ? TASK_INTERRUPTIBLE : TASK_UNINTERRUPTIBLE);
if (ret)
return -ERESTARTSYS;
if (test_bit(KEY_FLAG_NEGATIVE, &key->flags)) {
smp_rmb();
return key->reject_error;
}
return key_validate(key);
}
/*
* Allocate a new key in under-construction state and attempt to link it in to
* the requested keyring.
*
* May return a key that's already under construction instead if there was a
* race between two thread calling request_key().
*/
static int construct_alloc_key(struct keyring_search_context *ctx,
struct key *dest_keyring,
unsigned long flags,
struct key_user *user,
struct key **_key)
{
struct assoc_array_edit *edit;
struct key *key;
key_perm_t perm;
key_ref_t key_ref;
int ret;
kenter("%s,%s,,,",
ctx->index_key.type->name, ctx->index_key.description);
*_key = NULL;
mutex_lock(&user->cons_lock);
perm = KEY_POS_VIEW | KEY_POS_SEARCH | KEY_POS_LINK | KEY_POS_SETATTR;
perm |= KEY_USR_VIEW;
if (ctx->index_key.type->read)
perm |= KEY_POS_READ;
if (ctx->index_key.type == &key_type_keyring ||
ctx->index_key.type->update)
perm |= KEY_POS_WRITE;
key = key_alloc(ctx->index_key.type, ctx->index_key.description,
ctx->cred->fsuid, ctx->cred->fsgid, ctx->cred,
perm, flags, NULL);
if (IS_ERR(key))
goto alloc_failed;
set_bit(KEY_FLAG_USER_CONSTRUCT, &key->flags);
if (dest_keyring) {
ret = __key_link_begin(dest_keyring, &ctx->index_key, &edit);
if (ret < 0)
goto link_prealloc_failed;
}
/* attach the key to the destination keyring under lock, but we do need
* to do another check just in case someone beat us to it whilst we
* waited for locks */
mutex_lock(&key_construction_mutex);
key_ref = search_process_keyrings(ctx);
if (!IS_ERR(key_ref))
goto key_already_present;
if (dest_keyring)
__key_link(key, &edit);
mutex_unlock(&key_construction_mutex);
if (dest_keyring)
__key_link_end(dest_keyring, &ctx->index_key, edit);
mutex_unlock(&user->cons_lock);
*_key = key;
kleave(" = 0 [%d]", key_serial(key));
return 0;
/* the key is now present - we tell the caller that we found it by
* returning -EINPROGRESS */
key_already_present:
key_put(key);
mutex_unlock(&key_construction_mutex);
key = key_ref_to_ptr(key_ref);
if (dest_keyring) {
ret = __key_link_check_live_key(dest_keyring, key);
if (ret == 0)
__key_link(key, &edit);
__key_link_end(dest_keyring, &ctx->index_key, edit);
if (ret < 0)
goto link_check_failed;
}
mutex_unlock(&user->cons_lock);
*_key = key;
kleave(" = -EINPROGRESS [%d]", key_serial(key));
return -EINPROGRESS;
link_check_failed:
mutex_unlock(&user->cons_lock);
key_put(key);
kleave(" = %d [linkcheck]", ret);
return ret;
link_prealloc_failed:
mutex_unlock(&user->cons_lock);
key_put(key);
kleave(" = %d [prelink]", ret);
return ret;
alloc_failed:
mutex_unlock(&user->cons_lock);
kleave(" = %ld", PTR_ERR(key));
return PTR_ERR(key);
}
/*
* lookup a key given a key ID from userspace with a given permissions mask
* - don't create special keyrings unless so requested
* - partially constructed keys aren't found unless requested
*/
key_ref_t lookup_user_key(struct task_struct *context, key_serial_t id,
int create, int partial, key_perm_t perm)
{
key_ref_t key_ref, skey_ref;
struct key *key;
int ret;
if (!context)
context = current;
key_ref = ERR_PTR(-ENOKEY);
switch (id) {
case KEY_SPEC_THREAD_KEYRING:
if (!context->thread_keyring) {
if (!create)
goto error;
ret = install_thread_keyring(context);
if (ret < 0) {
key = ERR_PTR(ret);
goto error;
}
}
key = context->thread_keyring;
atomic_inc(&key->usage);
key_ref = make_key_ref(key, 1);
break;
case KEY_SPEC_PROCESS_KEYRING:
if (!context->signal->process_keyring) {
if (!create)
goto error;
ret = install_process_keyring(context);
if (ret < 0) {
key = ERR_PTR(ret);
goto error;
}
}
key = context->signal->process_keyring;
atomic_inc(&key->usage);
key_ref = make_key_ref(key, 1);
break;
case KEY_SPEC_SESSION_KEYRING:
if (!context->signal->session_keyring) {
/* always install a session keyring upon access if one
* doesn't exist yet */
ret = install_session_keyring(
context, context->user->session_keyring);
if (ret < 0)
goto error;
}
rcu_read_lock();
key = rcu_dereference(context->signal->session_keyring);
atomic_inc(&key->usage);
rcu_read_unlock();
key_ref = make_key_ref(key, 1);
break;
case KEY_SPEC_USER_KEYRING:
key = context->user->uid_keyring;
atomic_inc(&key->usage);
key_ref = make_key_ref(key, 1);
break;
case KEY_SPEC_USER_SESSION_KEYRING:
key = context->user->session_keyring;
atomic_inc(&key->usage);
key_ref = make_key_ref(key, 1);
break;
case KEY_SPEC_GROUP_KEYRING:
/* group keyrings are not yet supported */
key = ERR_PTR(-EINVAL);
goto error;
case KEY_SPEC_REQKEY_AUTH_KEY:
key = context->request_key_auth;
if (!key)
goto error;
atomic_inc(&key->usage);
key_ref = make_key_ref(key, 1);
break;
default:
key_ref = ERR_PTR(-EINVAL);
if (id < 1)
goto error;
key = key_lookup(id);
if (IS_ERR(key)) {
key_ref = ERR_PTR(PTR_ERR(key));
goto error;
}
key_ref = make_key_ref(key, 0);
/* check to see if we possess the key */
skey_ref = search_process_keyrings(key->type, key,
lookup_user_key_possessed,
current);
if (!IS_ERR(skey_ref)) {
key_put(key);
key_ref = skey_ref;
}
break;
}
/* check the status */
if (perm) {
ret = key_validate(key);
if (ret < 0)
goto invalid_key;
}
ret = -EIO;
if (!partial && !test_bit(KEY_FLAG_INSTANTIATED, &key->flags))
goto invalid_key;
/* check the permissions */
ret = key_task_permission(key_ref, context, perm);
if (ret < 0)
goto invalid_key;
error:
return key_ref;
invalid_key:
key_ref_put(key_ref);
key_ref = ERR_PTR(ret);
goto error;
} /* end lookup_user_key() */
/*
* search the process keyrings for the first matching key
* - we use the supplied match function to see if the description (or other
* feature of interest) matches
* - we return -EAGAIN if we didn't find any matching key
* - we return -ENOKEY if we found only negative matching keys
*/
key_ref_t search_process_keyrings(struct key_type *type,
const void *description,
key_match_func_t match,
struct task_struct *context)
{
struct request_key_auth *rka;
key_ref_t key_ref, ret, err;
might_sleep();
/* we want to return -EAGAIN or -ENOKEY if any of the keyrings were
* searchable, but we failed to find a key or we found a negative key;
* otherwise we want to return a sample error (probably -EACCES) if
* none of the keyrings were searchable
*
* in terms of priority: success > -ENOKEY > -EAGAIN > other error
*/
key_ref = NULL;
ret = NULL;
err = ERR_PTR(-EAGAIN);
/* search the thread keyring first */
if (context->thread_keyring) {
key_ref = keyring_search_aux(
make_key_ref(context->thread_keyring, 1),
context, type, description, match);
if (!IS_ERR(key_ref))
goto found;
switch (PTR_ERR(key_ref)) {
case -EAGAIN: /* no key */
if (ret)
break;
case -ENOKEY: /* negative key */
ret = key_ref;
break;
default:
err = key_ref;
break;
}
}
/* search the process keyring second */
if (context->signal->process_keyring) {
key_ref = keyring_search_aux(
make_key_ref(context->signal->process_keyring, 1),
context, type, description, match);
if (!IS_ERR(key_ref))
goto found;
switch (PTR_ERR(key_ref)) {
case -EAGAIN: /* no key */
if (ret)
break;
case -ENOKEY: /* negative key */
ret = key_ref;
break;
default:
err = key_ref;
break;
}
}
/* search the session keyring */
if (context->signal->session_keyring) {
rcu_read_lock();
key_ref = keyring_search_aux(
make_key_ref(rcu_dereference(
context->signal->session_keyring),
1),
context, type, description, match);
rcu_read_unlock();
if (!IS_ERR(key_ref))
goto found;
switch (PTR_ERR(key_ref)) {
case -EAGAIN: /* no key */
if (ret)
break;
case -ENOKEY: /* negative key */
ret = key_ref;
break;
default:
err = key_ref;
break;
}
}
/* or search the user-session keyring */
else {
key_ref = keyring_search_aux(
make_key_ref(context->user->session_keyring, 1),
context, type, description, match);
if (!IS_ERR(key_ref))
goto found;
switch (PTR_ERR(key_ref)) {
case -EAGAIN: /* no key */
if (ret)
break;
case -ENOKEY: /* negative key */
ret = key_ref;
break;
default:
err = key_ref;
break;
}
}
/* if this process has an instantiation authorisation key, then we also
* search the keyrings of the process mentioned there
* - we don't permit access to request_key auth keys via this method
*/
if (context->request_key_auth &&
context == current &&
type != &key_type_request_key_auth
) {
/* defend against the auth key being revoked */
down_read(&context->request_key_auth->sem);
if (key_validate(context->request_key_auth) == 0) {
rka = context->request_key_auth->payload.data;
key_ref = search_process_keyrings(type, description,
match, rka->context);
up_read(&context->request_key_auth->sem);
if (!IS_ERR(key_ref))
goto found;
switch (PTR_ERR(key_ref)) {
case -EAGAIN: /* no key */
if (ret)
break;
case -ENOKEY: /* negative key */
ret = key_ref;
break;
default:
err = key_ref;
break;
}
} else {
up_read(&context->request_key_auth->sem);
}
}
/* no key - decide on the error we're going to go for */
key_ref = ret ? ret : err;
found:
return key_ref;
} /* end search_process_keyrings() */
static int construct_alloc_key(struct key_type *type,
const char *description,
struct key *dest_keyring,
unsigned long flags,
struct key_user *user,
struct key **_key)
{
const struct cred *cred = current_cred();
unsigned long prealloc;
struct key *key;
key_ref_t key_ref;
int ret;
kenter("%s,%s,,,", type->name, description);
*_key = NULL;
mutex_lock(&user->cons_lock);
key = key_alloc(type, description, cred->fsuid, cred->fsgid, cred,
KEY_POS_ALL, flags);
if (IS_ERR(key))
goto alloc_failed;
set_bit(KEY_FLAG_USER_CONSTRUCT, &key->flags);
if (dest_keyring) {
ret = __key_link_begin(dest_keyring, type, description,
&prealloc);
if (ret < 0)
goto link_prealloc_failed;
}
/*
*/
mutex_lock(&key_construction_mutex);
key_ref = search_process_keyrings(type, description, type->match, cred);
if (!IS_ERR(key_ref))
goto key_already_present;
if (dest_keyring)
__key_link(dest_keyring, key, &prealloc);
mutex_unlock(&key_construction_mutex);
if (dest_keyring)
__key_link_end(dest_keyring, type, prealloc);
mutex_unlock(&user->cons_lock);
*_key = key;
kleave(" = 0 [%d]", key_serial(key));
return 0;
/*
*/
key_already_present:
key_put(key);
mutex_unlock(&key_construction_mutex);
key = key_ref_to_ptr(key_ref);
if (dest_keyring) {
ret = __key_link_check_live_key(dest_keyring, key);
if (ret == 0)
__key_link(dest_keyring, key, &prealloc);
__key_link_end(dest_keyring, type, prealloc);
if (ret < 0)
goto link_check_failed;
}
mutex_unlock(&user->cons_lock);
*_key = key;
kleave(" = -EINPROGRESS [%d]", key_serial(key));
return -EINPROGRESS;
link_check_failed:
mutex_unlock(&user->cons_lock);
key_put(key);
kleave(" = %d [linkcheck]", ret);
return ret;
link_prealloc_failed:
mutex_unlock(&user->cons_lock);
kleave(" = %d [prelink]", ret);
return ret;
alloc_failed:
mutex_unlock(&user->cons_lock);
kleave(" = %ld", PTR_ERR(key));
return PTR_ERR(key);
}