-/* request_key.c: request a key from userspace
+/* Request a key from userspace
*
- * Copyright (C) 2004-6 Red Hat, Inc. All Rights Reserved.
+ * Copyright (C) 2004-2007 Red Hat, Inc. All Rights Reserved.
* Written by David Howells (dhowells@redhat.com)
*
* This program is free software; you can redistribute it and/or
#include <linux/keyctl.h>
#include "internal.h"
-struct key_construction {
- struct list_head link; /* link in construction queue */
- struct key *key; /* key being constructed */
-};
+/*
+ * wait_on_bit() sleep function for uninterruptible waiting
+ */
+static int key_wait_bit(void *flags)
+{
+ schedule();
+ return 0;
+}
+
+/*
+ * wait_on_bit() sleep function for interruptible waiting
+ */
+static int key_wait_bit_intr(void *flags)
+{
+ schedule();
+ return signal_pending(current) ? -ERESTARTSYS : 0;
+}
+
+/*
+ * call to complete the construction of a key
+ */
+void complete_request_key(struct key_construction *cons, int error)
+{
+ kenter("{%d,%d},%d", cons->key->serial, cons->authkey->serial, error);
-/* when waiting for someone else's keys, you get added to this */
-DECLARE_WAIT_QUEUE_HEAD(request_key_conswq);
+ if (error < 0)
+ key_negate_and_link(cons->key, key_negative_timeout, NULL,
+ cons->authkey);
+ else
+ key_revoke(cons->authkey);
+
+ key_put(cons->key);
+ key_put(cons->authkey);
+ kfree(cons);
+}
+EXPORT_SYMBOL(complete_request_key);
-/*****************************************************************************/
/*
* request userspace finish the construction of a key
* - execute "/sbin/request-key <op> <key> <uid> <gid> <keyring> <keyring> <keyring>"
*/
-static int call_sbin_request_key(struct key *key,
- struct key *authkey,
+static int call_sbin_request_key(struct key_construction *cons,
const char *op,
void *aux)
{
struct task_struct *tsk = current;
key_serial_t prkey, sskey;
- struct key *keyring;
+ struct key *key = cons->key, *authkey = cons->authkey, *keyring;
char *argv[9], *envp[3], uid_str[12], gid_str[12];
char key_str[12], keyring_str[3][12];
char desc[20];
rcu_read_lock();
sskey = rcu_dereference(tsk->signal->session_keyring)->serial;
rcu_read_unlock();
- }
- else {
+ } else {
sskey = tsk->user->session_keyring->serial;
}
argv[i] = NULL;
/* do it */
- ret = call_usermodehelper_keys(argv[0], argv, envp, keyring, 1);
+ ret = call_usermodehelper_keys(argv[0], argv, envp, keyring,
+ UMH_WAIT_PROC);
+ kdebug("usermode -> 0x%x", ret);
+ if (ret >= 0) {
+ /* ret is the exit/wait code */
+ if (test_bit(KEY_FLAG_USER_CONSTRUCT, &key->flags) ||
+ key_validate(key) < 0)
+ ret = -ENOKEY;
+ else
+ /* ignore any errors from userspace if the key was
+ * instantiated */
+ ret = 0;
+ }
error_link:
key_put(keyring);
error_alloc:
kleave(" = %d", ret);
+ complete_request_key(cons, ret);
return ret;
+}
-} /* end call_sbin_request_key() */
-
-/*****************************************************************************/
/*
- * call out to userspace for the key
- * - called with the construction sem held, but the sem is dropped here
+ * call out to userspace for key construction
* - we ignore program failure and go on key status instead
*/
-static struct key *__request_key_construction(struct key_type *type,
- const char *description,
- const char *callout_info,
- void *aux,
- unsigned long flags)
+static int construct_key(struct key *key, const char *callout_info, void *aux)
{
+ struct key_construction *cons;
request_key_actor_t actor;
- struct key_construction cons;
- struct timespec now;
- struct key *key, *authkey;
- int ret, negated;
+ struct key *authkey;
+ int ret;
- kenter("%s,%s,%s,%lx", type->name, description, callout_info, flags);
+ kenter("%d,%s,%p", key->serial, callout_info, aux);
- /* create a key and add it to the queue */
- key = key_alloc(type, description,
- current->fsuid, current->fsgid, current, KEY_POS_ALL,
- flags);
- if (IS_ERR(key))
- goto alloc_failed;
-
- set_bit(KEY_FLAG_USER_CONSTRUCT, &key->flags);
-
- cons.key = key;
- list_add_tail(&cons.link, &key->user->consq);
-
- /* we drop the construction sem here on behalf of the caller */
- up_write(&key_construction_sem);
+ cons = kmalloc(sizeof(*cons), GFP_KERNEL);
+ if (!cons)
+ return -ENOMEM;
/* allocate an authorisation key */
authkey = request_key_auth_new(key, callout_info);
if (IS_ERR(authkey)) {
+ kfree(cons);
ret = PTR_ERR(authkey);
authkey = NULL;
- goto alloc_authkey_failed;
- }
-
- /* make the call */
- actor = call_sbin_request_key;
- if (type->request_key)
- actor = type->request_key;
- ret = actor(key, authkey, "create", aux);
- if (ret < 0)
- goto request_failed;
-
- /* if the key wasn't instantiated, then we want to give an error */
- ret = -ENOKEY;
- if (!test_bit(KEY_FLAG_INSTANTIATED, &key->flags))
- goto request_failed;
-
- key_revoke(authkey);
- key_put(authkey);
-
- down_write(&key_construction_sem);
- list_del(&cons.link);
- up_write(&key_construction_sem);
-
- /* also give an error if the key was negatively instantiated */
-check_not_negative:
- if (test_bit(KEY_FLAG_NEGATIVE, &key->flags)) {
- key_put(key);
- key = ERR_PTR(-ENOKEY);
- }
-
-out:
- kleave(" = %p", key);
- return key;
-
-request_failed:
- key_revoke(authkey);
- key_put(authkey);
-
-alloc_authkey_failed:
- /* it wasn't instantiated
- * - remove from construction queue
- * - mark the key as dead
- */
- negated = 0;
- down_write(&key_construction_sem);
-
- list_del(&cons.link);
-
- /* check it didn't get instantiated between the check and the down */
- if (!test_bit(KEY_FLAG_INSTANTIATED, &key->flags)) {
- set_bit(KEY_FLAG_NEGATIVE, &key->flags);
- set_bit(KEY_FLAG_INSTANTIATED, &key->flags);
- negated = 1;
- }
-
- clear_bit(KEY_FLAG_USER_CONSTRUCT, &key->flags);
-
- up_write(&key_construction_sem);
-
- if (!negated)
- goto check_not_negative; /* surprisingly, the key got
- * instantiated */
-
- /* set the timeout and store in the session keyring if we can */
- now = current_kernel_time();
- key->expiry = now.tv_sec + key_negative_timeout;
-
- if (current->signal->session_keyring) {
- struct key *keyring;
-
- rcu_read_lock();
- keyring = rcu_dereference(current->signal->session_keyring);
- atomic_inc(&keyring->usage);
- rcu_read_unlock();
-
- key_link(keyring, key);
- key_put(keyring);
- }
-
- key_put(key);
-
- /* notify anyone who was waiting */
- wake_up_all(&request_key_conswq);
-
- key = ERR_PTR(ret);
- goto out;
-
-alloc_failed:
- up_write(&key_construction_sem);
- goto out;
-
-} /* end __request_key_construction() */
-
-/*****************************************************************************/
-/*
- * call out to userspace to request the key
- * - we check the construction queue first to see if an appropriate key is
- * already being constructed by userspace
- */
-static struct key *request_key_construction(struct key_type *type,
- const char *description,
- const char *callout_info,
- void *aux,
- struct key_user *user,
- unsigned long flags)
-{
- struct key_construction *pcons;
- struct key *key, *ckey;
-
- DECLARE_WAITQUEUE(myself, current);
-
- kenter("%s,%s,{%d},%s,%lx",
- type->name, description, user->uid, callout_info, flags);
-
- /* see if there's such a key under construction already */
- down_write(&key_construction_sem);
-
- list_for_each_entry(pcons, &user->consq, link) {
- ckey = pcons->key;
-
- if (ckey->type != type)
- continue;
-
- if (type->match(ckey, description))
- goto found_key_under_construction;
+ } else {
+ cons->authkey = key_get(authkey);
+ cons->key = key_get(key);
+
+ /* make the call */
+ actor = call_sbin_request_key;
+ if (key->type->request_key)
+ actor = key->type->request_key;
+
+ ret = actor(cons, "create", aux);
+
+ /* check that the actor called complete_request_key() prior to
+ * returning an error */
+ WARN_ON(ret < 0 &&
+ !test_bit(KEY_FLAG_REVOKED, &authkey->flags));
+ key_put(authkey);
}
- /* see about getting userspace to construct the key */
- key = __request_key_construction(type, description, callout_info, aux,
- flags);
- error:
- kleave(" = %p", key);
- return key;
-
- /* someone else has the same key under construction
- * - we want to keep an eye on their key
- */
- found_key_under_construction:
- atomic_inc(&ckey->usage);
- up_write(&key_construction_sem);
-
- /* wait for the key to be completed one way or another */
- add_wait_queue(&request_key_conswq, &myself);
-
- for (;;) {
- set_current_state(TASK_INTERRUPTIBLE);
- if (!test_bit(KEY_FLAG_USER_CONSTRUCT, &ckey->flags))
- break;
- if (signal_pending(current))
- break;
- schedule();
- }
-
- set_current_state(TASK_RUNNING);
- remove_wait_queue(&request_key_conswq, &myself);
-
- /* we'll need to search this process's keyrings to see if the key is
- * now there since we can't automatically assume it's also available
- * there */
- key_put(ckey);
- ckey = NULL;
-
- key = NULL; /* request a retry */
- goto error;
-
-} /* end request_key_construction() */
+ kleave(" = %d", ret);
+ return ret;
+}
-/*****************************************************************************/
/*
- * link a freshly minted key to an appropriate destination keyring
+ * link a key to the appropriate destination keyring
+ * - the caller must hold a write lock on the destination keyring
*/
-static void request_key_link(struct key *key, struct key *dest_keyring)
+static void construct_key_make_link(struct key *key, struct key *dest_keyring)
{
struct task_struct *tsk = current;
struct key *drop = NULL;
break;
case KEY_REQKEY_DEFL_USER_SESSION_KEYRING:
- dest_keyring = current->user->session_keyring;
+ dest_keyring = tsk->user->session_keyring;
break;
case KEY_REQKEY_DEFL_USER_KEYRING:
- dest_keyring = current->user->uid_keyring;
+ dest_keyring = tsk->user->uid_keyring;
break;
case KEY_REQKEY_DEFL_GROUP_KEYRING:
}
/* and attach the key to it */
- key_link(dest_keyring, key);
-
+ __key_link(dest_keyring, key);
key_put(drop);
-
kleave("");
+}
-} /* end request_key_link() */
+/*
+ * 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)
+{
+ struct key *key;
+ key_ref_t key_ref;
+
+ kenter("%s,%s,,,", type->name, description);
+
+ mutex_lock(&user->cons_lock);
+
+ key = key_alloc(type, description,
+ current->fsuid, current->fsgid, current, KEY_POS_ALL,
+ flags);
+ if (IS_ERR(key))
+ goto alloc_failed;
+
+ set_bit(KEY_FLAG_USER_CONSTRUCT, &key->flags);
+
+ if (dest_keyring)
+ 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,
+ current);
+ if (!IS_ERR(key_ref))
+ goto key_already_present;
+
+ if (dest_keyring)
+ construct_key_make_link(key, dest_keyring);
+
+ mutex_unlock(&key_construction_mutex);
+ if (dest_keyring)
+ 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);
+}
+
+/*
+ * commence key construction
+ */
+static struct key *construct_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_user *user;
+ struct key *key;
+ int ret;
+
+ user = key_user_lookup(current->fsuid);
+ if (!user)
+ return ERR_PTR(-ENOMEM);
+
+ ret = construct_alloc_key(type, description, dest_keyring, flags, user,
+ &key);
+ key_user_put(user);
+
+ if (ret == 0) {
+ ret = construct_key(key, callout_info, aux);
+ if (ret < 0)
+ goto construction_failed;
+ }
+
+ return key;
+
+construction_failed:
+ key_negate_and_link(key, key_negative_timeout, NULL, NULL);
+ key_put(key);
+ return ERR_PTR(ret);
+}
-/*****************************************************************************/
/*
* request a key
* - search the process's keyrings
struct key *dest_keyring,
unsigned long flags)
{
- struct key_user *user;
struct key *key;
key_ref_t key_ref;
key_ref = search_process_keyrings(type, description, type->match,
current);
- kdebug("search 1: %p", key_ref);
-
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 {
+ } 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;
- /* - get hold of the user's construction queue */
- user = key_user_lookup(current->fsuid);
- if (!user)
- goto nomem;
-
- for (;;) {
- if (signal_pending(current))
- goto interrupted;
-
- /* ask userspace (returns NULL if it waited on a key
- * being constructed) */
- key = request_key_construction(type, description,
- callout_info, aux,
- user, flags);
- if (key)
- break;
-
- /* someone else made the key we want, so we need to
- * search again as it might now be available to us */
- key_ref = search_process_keyrings(type, description,
- type->match,
- current);
-
- kdebug("search 2: %p", key_ref);
-
- if (!IS_ERR(key_ref)) {
- key = key_ref_to_ptr(key_ref);
- break;
- }
-
- if (PTR_ERR(key_ref) != -EAGAIN) {
- key = ERR_PTR(PTR_ERR(key_ref));
- break;
- }
- }
-
- key_user_put(user);
-
- /* link the new key into the appropriate keyring */
- if (!IS_ERR(key))
- request_key_link(key, dest_keyring);
+ key = construct_key_and_link(type, description, callout_info,
+ aux, dest_keyring, flags);
}
error:
kleave(" = %p", key);
return key;
+}
-nomem:
- key = ERR_PTR(-ENOMEM);
- goto error;
-
-interrupted:
- key_user_put(user);
- key = ERR_PTR(-EINTR);
- goto error;
+/*
+ * wait for construction of a key to complete
+ */
+int wait_for_key_construction(struct key *key, bool intr)
+{
+ int ret;
-} /* end request_key_and_link() */
+ ret = wait_on_bit(&key->flags, KEY_FLAG_USER_CONSTRUCT,
+ intr ? key_wait_bit_intr : key_wait_bit,
+ intr ? TASK_INTERRUPTIBLE : TASK_UNINTERRUPTIBLE);
+ if (ret < 0)
+ return ret;
+ return key_validate(key);
+}
+EXPORT_SYMBOL(wait_for_key_construction);
-/*****************************************************************************/
/*
* 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
+ * - waits uninterruptible for creation to complete
*/
struct key *request_key(struct key_type *type,
const char *description,
const char *callout_info)
{
- return request_key_and_link(type, description, callout_info, NULL,
- NULL, KEY_ALLOC_IN_QUOTA);
-
-} /* end request_key() */
-
+ struct key *key;
+ int ret;
+
+ key = request_key_and_link(type, description, callout_info, NULL,
+ NULL, KEY_ALLOC_IN_QUOTA);
+ if (!IS_ERR(key)) {
+ ret = wait_for_key_construction(key, false);
+ if (ret < 0) {
+ key_put(key);
+ return ERR_PTR(ret);
+ }
+ }
+ return key;
+}
EXPORT_SYMBOL(request_key);
-/*****************************************************************************/
/*
* request a key with auxiliary data for the upcaller
* - 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
+ * - waits uninterruptible for creation to complete
*/
struct key *request_key_with_auxdata(struct key_type *type,
const char *description,
const char *callout_info,
void *aux)
{
- return request_key_and_link(type, description, callout_info, aux,
- NULL, KEY_ALLOC_IN_QUOTA);
+ struct key *key;
+ int ret;
+
+ key = request_key_and_link(type, description, callout_info, aux,
+ NULL, KEY_ALLOC_IN_QUOTA);
+ if (!IS_ERR(key)) {
+ ret = wait_for_key_construction(key, false);
+ if (ret < 0) {
+ key_put(key);
+ return ERR_PTR(ret);
+ }
+ }
+ return key;
+}
+EXPORT_SYMBOL(request_key_with_auxdata);
-} /* end request_key_with_auxdata() */
+/*
+ * request a key (allow async construction)
+ * - 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
+ */
+struct key *request_key_async(struct key_type *type,
+ const char *description,
+ const char *callout_info)
+{
+ return request_key_and_link(type, description, callout_info, NULL,
+ NULL, KEY_ALLOC_IN_QUOTA);
+}
+EXPORT_SYMBOL(request_key_async);
-EXPORT_SYMBOL(request_key_with_auxdata);
+/*
+ * request a key with auxiliary data for the upcaller (allow async construction)
+ * - 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
+ */
+struct key *request_key_async_with_auxdata(struct key_type *type,
+ const char *description,
+ const char *callout_info,
+ void *aux)
+{
+ return request_key_and_link(type, description, callout_info, aux,
+ NULL, KEY_ALLOC_IN_QUOTA);
+}
+EXPORT_SYMBOL(request_key_async_with_auxdata);
git.samba.org / sfrench / cifs-2.6.git / blobdiff