/* process_keys.c: management of a process's keyrings
*
- * Copyright (C) 2004 Red Hat, Inc. All Rights Reserved.
+ * Copyright (C) 2004-5 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 <linux/fs.h>
#include <linux/err.h>
+#include <linux/mutex.h>
#include <asm/uaccess.h>
#include "internal.h"
/* session keyring create vs join semaphore */
-static DECLARE_MUTEX(key_session_sem);
+static DEFINE_MUTEX(key_session_mutex);
/* the root user's tracking struct */
struct key_user root_key_user = {
.serial = 2,
.type = &key_type_keyring,
.user = &root_key_user,
- .lock = RW_LOCK_UNLOCKED,
.sem = __RWSEM_INITIALIZER(root_user_keyring.sem),
- .perm = KEY_USR_ALL,
- .flags = KEY_FLAG_INSTANTIATED,
+ .perm = (KEY_POS_ALL & ~KEY_POS_SETATTR) | KEY_USR_ALL,
+ .flags = 1 << KEY_FLAG_INSTANTIATED,
.description = "_uid.0",
#ifdef KEY_DEBUGGING
.magic = KEY_DEBUG_MAGIC,
.serial = 1,
.type = &key_type_keyring,
.user = &root_key_user,
- .lock = RW_LOCK_UNLOCKED,
.sem = __RWSEM_INITIALIZER(root_session_keyring.sem),
- .perm = KEY_USR_ALL,
- .flags = KEY_FLAG_INSTANTIATED,
+ .perm = (KEY_POS_ALL & ~KEY_POS_SETATTR) | KEY_USR_ALL,
+ .flags = 1 << KEY_FLAG_INSTANTIATED,
.description = "_uid_ses.0",
#ifdef KEY_DEBUGGING
.magic = KEY_DEBUG_MAGIC,
user->session_keyring = session_keyring;
ret = 0;
- error:
+error:
return ret;
} /* end alloc_uid_keyring() */
ret = 0;
key_put(old);
- error:
+error:
return ret;
} /* end install_thread_keyring() */
/*
* make sure a process keyring is installed
*/
-static int install_process_keyring(struct task_struct *tsk)
+int install_process_keyring(struct task_struct *tsk)
{
- unsigned long flags;
struct key *keyring;
char buf[20];
int ret;
+ might_sleep();
+
if (!tsk->signal->process_keyring) {
sprintf(buf, "_pid.%u", tsk->tgid);
goto error;
}
- /* attach or swap keyrings */
- spin_lock_irqsave(&tsk->sighand->siglock, flags);
+ /* attach keyring */
+ spin_lock_irq(&tsk->sighand->siglock);
if (!tsk->signal->process_keyring) {
tsk->signal->process_keyring = keyring;
keyring = NULL;
}
- spin_unlock_irqrestore(&tsk->sighand->siglock, flags);
+ spin_unlock_irq(&tsk->sighand->siglock);
key_put(keyring);
}
ret = 0;
- error:
+error:
return ret;
} /* end install_process_keyring() */
static int install_session_keyring(struct task_struct *tsk,
struct key *keyring)
{
- unsigned long flags;
struct key *old;
char buf[20];
- int ret;
+
+ might_sleep();
/* create an empty session keyring */
if (!keyring) {
sprintf(buf, "_ses.%u", tsk->tgid);
keyring = keyring_alloc(buf, tsk->uid, tsk->gid, 1, NULL);
- if (IS_ERR(keyring)) {
- ret = PTR_ERR(keyring);
- goto error;
- }
+ if (IS_ERR(keyring))
+ return PTR_ERR(keyring);
}
else {
atomic_inc(&keyring->usage);
}
/* install the keyring */
- spin_lock_irqsave(&tsk->sighand->siglock, flags);
+ spin_lock_irq(&tsk->sighand->siglock);
old = tsk->signal->session_keyring;
- tsk->signal->session_keyring = keyring;
- spin_unlock_irqrestore(&tsk->sighand->siglock, flags);
+ rcu_assign_pointer(tsk->signal->session_keyring, keyring);
+ spin_unlock_irq(&tsk->sighand->siglock);
- ret = 0;
+ /* 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();
+ key_put(old);
+ }
- key_put(old);
- error:
- return ret;
+ return 0;
} /* end install_session_keyring() */
*/
int copy_thread_group_keys(struct task_struct *tsk)
{
- unsigned long flags;
-
key_check(current->thread_group->session_keyring);
key_check(current->thread_group->process_keyring);
tsk->signal->process_keyring = NULL;
/* same session keyring */
- spin_lock_irqsave(¤t->sighand->siglock, flags);
+ rcu_read_lock();
tsk->signal->session_keyring =
- key_get(current->signal->session_keyring);
- spin_unlock_irqrestore(¤t->sighand->siglock, flags);
+ key_get(rcu_dereference(current->signal->session_keyring));
+ rcu_read_unlock();
return 0;
int copy_keys(unsigned long clone_flags, struct task_struct *tsk)
{
key_check(tsk->thread_keyring);
+ key_check(tsk->request_key_auth);
/* no thread keyring yet */
tsk->thread_keyring = NULL;
+
+ /* copy the request_key() authorisation for this thread */
+ key_get(tsk->request_key_auth);
+
return 0;
} /* end copy_keys() */
/*****************************************************************************/
/*
- * dispose of keys upon thread exit
+ * dispose of per-thread keys upon thread exit
*/
void exit_keys(struct task_struct *tsk)
{
key_put(tsk->thread_keyring);
+ key_put(tsk->request_key_auth);
} /* end exit_keys() */
*/
int exec_keys(struct task_struct *tsk)
{
- unsigned long flags;
struct key *old;
/* newly exec'd tasks don't get a thread keyring */
key_put(old);
/* discard the process keyring from a newly exec'd task */
- spin_lock_irqsave(&tsk->sighand->siglock, flags);
+ spin_lock_irq(&tsk->sighand->siglock);
old = tsk->signal->process_keyring;
tsk->signal->process_keyring = NULL;
- spin_unlock_irqrestore(&tsk->sighand->siglock, flags);
+ spin_unlock_irq(&tsk->sighand->siglock);
key_put(old);
/* update the ownership of the thread keyring */
if (tsk->thread_keyring) {
down_write(&tsk->thread_keyring->sem);
- write_lock(&tsk->thread_keyring->lock);
tsk->thread_keyring->uid = tsk->fsuid;
- write_unlock(&tsk->thread_keyring->lock);
up_write(&tsk->thread_keyring->sem);
}
/* update the ownership of the thread keyring */
if (tsk->thread_keyring) {
down_write(&tsk->thread_keyring->sem);
- write_lock(&tsk->thread_keyring->lock);
tsk->thread_keyring->gid = tsk->fsgid;
- write_unlock(&tsk->thread_keyring->lock);
up_write(&tsk->thread_keyring->sem);
}
* - we return -EAGAIN if we didn't find any matching key
* - we return -ENOKEY if we found only negative matching keys
*/
-struct key *search_process_keyrings_aux(struct key_type *type,
- const void *description,
- key_match_func_t match)
+key_ref_t search_process_keyrings(struct key_type *type,
+ const void *description,
+ key_match_func_t match,
+ struct task_struct *context)
{
- struct task_struct *tsk = current;
- unsigned long flags;
- struct key *key, *ret, *err, *tmp;
+ struct request_key_auth *rka;
+ key_ref_t key_ref, ret, err;
/* 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;
*
* in terms of priority: success > -ENOKEY > -EAGAIN > other error
*/
- key = NULL;
+ key_ref = NULL;
ret = NULL;
err = ERR_PTR(-EAGAIN);
/* search the thread keyring first */
- if (tsk->thread_keyring) {
- key = keyring_search_aux(tsk->thread_keyring, type,
- description, match);
- if (!IS_ERR(key))
+ 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)) {
+ switch (PTR_ERR(key_ref)) {
case -EAGAIN: /* no key */
if (ret)
break;
case -ENOKEY: /* negative key */
- ret = key;
+ ret = key_ref;
break;
default:
- err = key;
+ err = key_ref;
break;
}
}
/* search the process keyring second */
- if (tsk->signal->process_keyring) {
- key = keyring_search_aux(tsk->signal->process_keyring,
- type, description, match);
- if (!IS_ERR(key))
+ 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)) {
+ switch (PTR_ERR(key_ref)) {
case -EAGAIN: /* no key */
if (ret)
break;
case -ENOKEY: /* negative key */
- ret = key;
+ ret = key_ref;
break;
default:
- err = key;
+ 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;
- /* search the session keyring last */
- spin_lock_irqsave(&tsk->sighand->siglock, flags);
+ 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;
+ }
+ }
- tmp = tsk->signal->session_keyring;
- if (!tmp)
- tmp = tsk->user->session_keyring;
- atomic_inc(&tmp->usage);
+ /* 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 &&
+ key_validate(context->request_key_auth) == 0
+ ) {
+ rka = context->request_key_auth->payload.data;
- spin_unlock_irqrestore(&tsk->sighand->siglock, flags);
+ key_ref = search_process_keyrings(type, description, match,
+ rka->context);
- key = keyring_search_aux(tmp, type, description, match);
- key_put(tmp);
- if (!IS_ERR(key))
- goto found;
+ if (!IS_ERR(key_ref))
+ goto found;
- switch (PTR_ERR(key)) {
- case -EAGAIN: /* no key */
- if (ret)
+ switch (PTR_ERR(key_ref)) {
+ case -EAGAIN: /* no key */
+ if (ret)
+ break;
+ case -ENOKEY: /* negative key */
+ ret = key_ref;
break;
- case -ENOKEY: /* negative key */
- ret = key;
- break;
- default:
- err = key;
- break;
+ default:
+ err = key_ref;
+ break;
+ }
}
/* no key - decide on the error we're going to go for */
- key = ret ? ret : err;
+ key_ref = ret ? ret : err;
- found:
- return key;
+found:
+ return key_ref;
-} /* end search_process_keyrings_aux() */
+} /* end search_process_keyrings() */
/*****************************************************************************/
/*
- * search the process keyrings for the first matching key
- * - we return -EAGAIN if we didn't find any matching key
- * - we return -ENOKEY if we found only negative matching keys
+ * see if the key we're looking at is the target key
*/
-struct key *search_process_keyrings(struct key_type *type,
- const char *description)
+static int lookup_user_key_possessed(const struct key *key, const void *target)
{
- return search_process_keyrings_aux(type, description, type->match);
+ return key == target;
-} /* end search_process_keyrings() */
+} /* end lookup_user_key_possessed() */
/*****************************************************************************/
/*
* - don't create special keyrings unless so requested
* - partially constructed keys aren't found unless requested
*/
-struct key *lookup_user_key(key_serial_t id, int create, int partial,
- key_perm_t perm)
+key_ref_t lookup_user_key(struct task_struct *context, key_serial_t id,
+ int create, int partial, key_perm_t perm)
{
- struct task_struct *tsk = current;
- unsigned long flags;
+ key_ref_t key_ref, skey_ref;
struct key *key;
int ret;
- key = ERR_PTR(-ENOKEY);
+ if (!context)
+ context = current;
+
+ key_ref = ERR_PTR(-ENOKEY);
switch (id) {
case KEY_SPEC_THREAD_KEYRING:
- if (!tsk->thread_keyring) {
+ if (!context->thread_keyring) {
if (!create)
goto error;
- ret = install_thread_keyring(tsk);
+ ret = install_thread_keyring(context);
if (ret < 0) {
key = ERR_PTR(ret);
goto error;
}
}
- key = tsk->thread_keyring;
+ key = context->thread_keyring;
atomic_inc(&key->usage);
+ key_ref = make_key_ref(key, 1);
break;
case KEY_SPEC_PROCESS_KEYRING:
- if (!tsk->signal->process_keyring) {
+ if (!context->signal->process_keyring) {
if (!create)
goto error;
- ret = install_process_keyring(tsk);
+ ret = install_process_keyring(context);
if (ret < 0) {
key = ERR_PTR(ret);
goto error;
}
}
- key = tsk->signal->process_keyring;
+ key = context->signal->process_keyring;
atomic_inc(&key->usage);
+ key_ref = make_key_ref(key, 1);
break;
case KEY_SPEC_SESSION_KEYRING:
- if (!tsk->signal->session_keyring) {
+ if (!context->signal->session_keyring) {
/* always install a session keyring upon access if one
* doesn't exist yet */
ret = install_session_keyring(
- tsk, tsk->user->session_keyring);
+ context, context->user->session_keyring);
if (ret < 0)
goto error;
}
- spin_lock_irqsave(&tsk->sighand->siglock, flags);
- key = tsk->signal->session_keyring;
+ rcu_read_lock();
+ key = rcu_dereference(context->signal->session_keyring);
atomic_inc(&key->usage);
- spin_unlock_irqrestore(&tsk->sighand->siglock, flags);
+ rcu_read_unlock();
+ key_ref = make_key_ref(key, 1);
break;
case KEY_SPEC_USER_KEYRING:
- key = tsk->user->uid_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 = tsk->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:
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 = ERR_PTR(-EINVAL);
+ key_ref = ERR_PTR(-EINVAL);
if (id < 1)
goto error;
key = key_lookup(id);
- if (IS_ERR(key))
+ 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 and permissions */
+ /* check the status */
if (perm) {
ret = key_validate(key);
if (ret < 0)
}
ret = -EIO;
- if (!partial && !(key->flags & KEY_FLAG_INSTANTIATED))
+ if (!partial && !test_bit(KEY_FLAG_INSTANTIATED, &key->flags))
goto invalid_key;
- ret = -EACCES;
- if (!key_permission(key, perm))
+ /* check the permissions */
+ ret = key_task_permission(key_ref, context, perm);
+ if (ret < 0)
goto invalid_key;
- error:
- return key;
+error:
+ return key_ref;
- invalid_key:
- key_put(key);
- key = ERR_PTR(ret);
+invalid_key:
+ key_ref_put(key_ref);
+ key_ref = ERR_PTR(ret);
goto error;
} /* end lookup_user_key() */
long join_session_keyring(const char *name)
{
struct task_struct *tsk = current;
- unsigned long flags;
struct key *keyring;
long ret;
if (ret < 0)
goto error;
- spin_lock_irqsave(&tsk->sighand->siglock, flags);
- ret = tsk->signal->session_keyring->serial;
- spin_unlock_irqrestore(&tsk->sighand->siglock, flags);
+ rcu_read_lock();
+ ret = rcu_dereference(tsk->signal->session_keyring)->serial;
+ rcu_read_unlock();
goto error;
}
/* allow the user to join or create a named keyring */
- down(&key_session_sem);
+ mutex_lock(&key_session_mutex);
/* look for an existing keyring of this name */
keyring = find_keyring_by_name(name, 0);
keyring = keyring_alloc(name, tsk->uid, tsk->gid, 0, NULL);
if (IS_ERR(keyring)) {
ret = PTR_ERR(keyring);
- goto error;
+ goto error2;
}
}
else if (IS_ERR(keyring)) {
ret = keyring->serial;
key_put(keyring);
- error2:
- up(&key_session_sem);
- error:
+error2:
+ mutex_unlock(&key_session_mutex);
+error:
return ret;
} /* end join_session_keyring() */
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