/* keyctl.c: userspace keyctl operations
*
* Copyright (C) 2004 Red Hat, Inc. All Rights Reserved.
* Written by David Howells (dhowells@redhat.com)
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version
* 2 of the License, or (at your option) any later version.
*/
#include <linux/module.h>
#include <linux/init.h>
#include <linux/sched.h>
#include <linux/slab.h>
#include <linux/syscalls.h>
#include <linux/keyctl.h>
#include <linux/fs.h>
#include <linux/err.h>
#include <asm/uaccess.h>
#include "internal.h"
/*****************************************************************************/
/*
* extract the description of a new key from userspace and either add it as a
* new key to the specified keyring or update a matching key in that keyring
* - the keyring must be writable
* - returns the new key's serial number
* - implements add_key()
*/
asmlinkage long sys_add_key(const char __user *_type,
const char __user *_description,
const void __user *_payload,
size_t plen,
key_serial_t ringid)
{
struct key *keyring, *key;
char type[32], *description;
void *payload;
long dlen, ret;
ret = -EINVAL;
if (plen > 32767)
goto error;
/* draw all the data into kernel space */
ret = strncpy_from_user(type, _type, sizeof(type) - 1);
if (ret < 0)
goto error;
type[31] = '\0';
ret = -EFAULT;
dlen = strnlen_user(_description, PAGE_SIZE - 1);
if (dlen <= 0)
goto error;
ret = -EINVAL;
if (dlen > PAGE_SIZE - 1)
goto error;
ret = -ENOMEM;
description = kmalloc(dlen + 1, GFP_KERNEL);
if (!description)
goto error;
ret = -EFAULT;
if (copy_from_user(description, _description, dlen + 1) != 0)
goto error2;
/* pull the payload in if one was supplied */
payload = NULL;
if (_payload) {
ret = -ENOMEM;
payload = kmalloc(plen, GFP_KERNEL);
if (!payload)
goto error2;
ret = -EFAULT;
if (copy_from_user(payload, _payload, plen) != 0)
goto error3;
}
/* find the target keyring (which must be writable) */
keyring = lookup_user_key(ringid, 1, 0, KEY_WRITE);
if (IS_ERR(keyring)) {
ret = PTR_ERR(keyring);
goto error3;
}
/* create or update the requested key and add it to the target
* keyring */
key = key_create_or_update(keyring, type, description,
payload, plen, 0);
if (!IS_ERR(key)) {
ret = key->serial;
key_put(key);
}
else {
ret = PTR_ERR(key);
}
key_put(keyring);
error3:
kfree(payload);
error2:
kfree(description);
error:
return ret;
} /* end sys_add_key() */
/*****************************************************************************/
/*
* search the process keyrings for a matching key
* - nested keyrings may also be searched if they have Search permission
* - if a key is found, it will be attached to the destination keyring if
* there's one specified
* - /sbin/request-key will be invoked if _callout_info is non-NULL
* - the _callout_info string will be passed to /sbin/request-key
* - if the _callout_info string is empty, it will be rendered as "-"
* - implements request_key()
*/
asmlinkage long sys_request_key(const char __user *_type,
const char __user *_description,
const char __user *_callout_info,
key_serial_t destringid)
{
struct key_type *ktype;
struct key *key, *dest;
char type[32], *description, *callout_info;
long dlen, ret;
/* pull the type into kernel space */
ret = strncpy_from_user(type, _type, sizeof(type) - 1);
if (ret < 0)
goto error;
type[31] = '\0';
/* pull the description into kernel space */
ret = -EFAULT;
dlen = strnlen_user(_description, PAGE_SIZE - 1);
if (dlen <= 0)
goto error;
ret = -EINVAL;
if (dlen > PAGE_SIZE - 1)
goto error;
ret = -ENOMEM;
description = kmalloc(dlen + 1, GFP_KERNEL);
if (!description)
goto error;
ret = -EFAULT;
if (copy_from_user(description, _description, dlen + 1) != 0)
goto error2;
/* pull the callout info into kernel space */
callout_info = NULL;
if (_callout_info) {
ret = -EFAULT;
dlen = strnlen_user(_callout_info, PAGE_SIZE - 1);
if (dlen <= 0)
goto error2;
ret = -EINVAL;
if (dlen > PAGE_SIZE - 1)
goto error2;
ret = -ENOMEM;
callout_info = kmalloc(dlen + 1, GFP_KERNEL);
if (!callout_info)
goto error2;
ret = -EFAULT;
if (copy_from_user(callout_info, _callout_info, dlen + 1) != 0)
goto error3;
}
/* get the destination keyring if specified */
dest = NULL;
if (destringid) {
dest = lookup_user_key(destringid, 1, 0, KEY_WRITE);
if (IS_ERR(dest)) {
ret = PTR_ERR(dest);
goto error3;
}
}
/* find the key type */
ktype = key_type_lookup(type);
if (IS_ERR(ktype)) {
ret = PTR_ERR(ktype);
goto error4;
}
/* do the search */
key = request_key(ktype, description, callout_info);
if (IS_ERR(key)) {
ret = PTR_ERR(key);
goto error5;
}
/* link the resulting key to the destination keyring */
if (dest) {
ret = key_link(dest, key);
if (ret < 0)
goto error6;
}
ret = key->serial;
error6:
key_put(key);
error5:
key_type_put(ktype);
error4:
key_put(dest);
error3:
kfree(callout_info);
error2:
kfree(description);
error:
return ret;
} /* end sys_request_key() */
/*****************************************************************************/
/*
* get the ID of the specified process keyring
* - the keyring must have search permission to be found
* - implements keyctl(KEYCTL_GET_KEYRING_ID)
*/
long keyctl_get_keyring_ID(key_serial_t id, int create)
{
struct key *key;
long ret;
key = lookup_user_key(id, create, 0, KEY_SEARCH);
if (IS_ERR(key)) {
ret = PTR_ERR(key);
goto error;
}
ret = key->serial;
key_put(key);
error:
return ret;
} /* end keyctl_get_keyring_ID() */
/*****************************************************************************/
/*
* join the session keyring
* - implements keyctl(KEYCTL_JOIN_SESSION_KEYRING)
*/
long keyctl_join_session_keyring(const char __user *_name)
{
char *name;
long nlen, ret;
/* fetch the name from userspace */
name = NULL;
if (_name) {
ret = -EFAULT;
nlen = strnlen_user(_name, PAGE_SIZE - 1);
if (nlen <= 0)
goto error;
ret = -EINVAL;
if (nlen > PAGE_SIZE - 1)
goto error;
ret = -ENOMEM;
name = kmalloc(nlen + 1, GFP_KERNEL);
if (!name)
goto error;
ret = -EFAULT;
if (copy_from_user(name, _name, nlen + 1) != 0)
goto error2;
}
/* join the session */
ret = join_session_keyring(name);
error2:
kfree(name);
error:
return ret;
} /* end keyctl_join_session_keyring() */
/*****************************************************************************/
/*
* update a key's data payload
* - the key must be writable
* - implements keyctl(KEYCTL_UPDATE)
*/
long keyctl_update_key(key_serial_t id,
const void __user *_payload,
size_t plen)
{
struct key *key;
void *payload;
long ret;
ret = -EINVAL;
if (plen > PAGE_SIZE)
goto error;
/* pull the payload in if one was supplied */
payload = NULL;
if (_payload) {
ret = -ENOMEM;
payload = kmalloc(plen, GFP_KERNEL);
if (!payload)
goto error;
ret = -EFAULT;
if (copy_from_user(payload, _payload, plen) != 0)
goto error2;
}
/* find the target key (which must be writable) */
key = lookup_user_key(id, 0, 0, KEY_WRITE);
if (IS_ERR(key)) {
ret = PTR_ERR(key);
goto error2;
}
/* update the key */
ret = key_update(key, payload, plen);
key_put(key);
error2:
kfree(payload);
error:
return ret;
} /* end keyctl_update_key() */
/*****************************************************************************/
/*
* revoke a key
* - the key must be writable
* - implements keyctl(KEYCTL_REVOKE)
*/
long keyctl_revoke_key(key_serial_t id)
{
struct key *key;
long ret;
key = lookup_user_key(id, 0, 0, KEY_WRITE);
if (IS_ERR(key)) {
ret = PTR_ERR(key);
goto error;
}
key_revoke(key);
ret = 0;
key_put(key);
error:
return 0;
} /* end keyctl_revoke_key() */
/*****************************************************************************/
/*
* clear the specified process keyring
* - the keyring must be writable
* - implements keyctl(KEYCTL_CLEAR)
*/
long keyctl_keyring_clear(key_serial_t ringid)
{
struct key *keyring;
long ret;
keyring = lookup_user_key(ringid, 1, 0, KEY_WRITE);
if (IS_ERR(keyring)) {
ret = PTR_ERR(keyring);
goto error;
}
ret = keyring_clear(keyring);
key_put(keyring);
error:
return ret;
} /* end keyctl_keyring_clear() */
/*****************************************************************************/
/*
* link a key into a keyring
* - the keyring must be writable
* - the key must be linkable
* - implements keyctl(KEYCTL_LINK)
*/
long keyctl_keyring_link(key_serial_t id, key_serial_t ringid)
{
struct key *keyring, *key;
long ret;
keyring = lookup_user_key(ringid, 1, 0, KEY_WRITE);
if (IS_ERR(keyring)) {
ret = PTR_ERR(keyring);
goto error;
}
key = lookup_user_key(id, 1, 0, KEY_LINK);
if (IS_ERR(key)) {
ret = PTR_ERR(key);
goto error2;
}
ret = key_link(keyring, key);
key_put(key);
error2:
key_put(keyring);
error:
return ret;
} /* end keyctl_keyring_link() */
/*****************************************************************************/
/*
* unlink the first attachment of a key from a keyring
* - the keyring must be writable
* - we don't need any permissions on the key
* - implements keyctl(KEYCTL_UNLINK)
*/
long keyctl_keyring_unlink(key_serial_t id, key_serial_t ringid)
{
struct key *keyring, *key;
long ret;
keyring = lookup_user_key(ringid, 0, 0, KEY_WRITE);
if (IS_ERR(keyring)) {
ret = PTR_ERR(keyring);
goto error;
}
key = lookup_user_key(id, 0, 0, 0);
if (IS_ERR(key)) {
ret = PTR_ERR(key);
goto error2;
}
ret = key_unlink(keyring, key);
key_put(key);
error2:
key_put(keyring);
error:
return ret;
} /* end keyctl_keyring_unlink() */
/*****************************************************************************/
/*
* describe a user key
* - the key must have view permission
* - if there's a buffer, we place up to buflen bytes of data into it
* - unless there's an error, we return the amount of description available,
* irrespective of how much we may have copied
* - the description is formatted thus:
* type;uid;gid;perm;description<NUL>
* - implements keyctl(KEYCTL_DESCRIBE)
*/
long keyctl_describe_key(key_serial_t keyid,
char __user *buffer,
size_t buflen)
{
struct key *key;
char *tmpbuf;
long ret;
key = lookup_user_key(keyid, 0, 1, KEY_VIEW);
if (IS_ERR(key)) {
ret = PTR_ERR(key);
goto error;
}
/* calculate how much description we're going to return */
ret = -ENOMEM;
tmpbuf = kmalloc(PAGE_SIZE, GFP_KERNEL);
if (!tmpbuf)
goto error2;
ret = snprintf(tmpbuf, PAGE_SIZE - 1,
"%s;%d;%d;%06x;%s",
key->type->name,
key->uid,
key->gid,
key->perm,
key->description ? key->description :""
);
/* include a NUL char at the end of the data */
if (ret > PAGE_SIZE - 1)
ret = PAGE_SIZE - 1;
tmpbuf[ret] = 0;
ret++;
/* consider returning the data */
if (buffer && buflen > 0) {
if (buflen > ret)
buflen = ret;
if (copy_to_user(buffer, tmpbuf, buflen) != 0)
ret = -EFAULT;
}
kfree(tmpbuf);
error2:
key_put(key);
error:
return ret;
} /* end keyctl_describe_key() */
/*****************************************************************************/
/*
* search the specified keyring for a matching key
* - the start keyring must be searchable
* - nested keyrings may also be searched if they are searchable
* - only keys with search permission may be found
* - if a key is found, it will be attached to the destination keyring if
* there's one specified
* - implements keyctl(KEYCTL_SEARCH)
*/
long keyctl_keyring_search(key_serial_t ringid,
const char __user *_type,
const char __user *_description,
key_serial_t destringid)
{
struct key_type *ktype;
struct key *keyring, *key, *dest;
char type[32], *description;
long dlen, ret;
/* pull the type and description into kernel space */
ret = strncpy_from_user(type, _type, sizeof(type) - 1);
if (ret < 0)
goto error;
type[31] = '\0';
ret = -EFAULT;
dlen = strnlen_user(_description, PAGE_SIZE - 1);
if (dlen <= 0)
goto error;
ret = -EINVAL;
if (dlen > PAGE_SIZE - 1)
goto error;
ret = -ENOMEM;
description = kmalloc(dlen + 1, GFP_KERNEL);
if (!description)
goto error;
ret = -EFAULT;
if (copy_from_user(description, _description, dlen + 1) != 0)
goto error2;
/* get the keyring at which to begin the search */
keyring = lookup_user_key(ringid, 0, 0, KEY_SEARCH);
if (IS_ERR(keyring)) {
ret = PTR_ERR(keyring);
goto error2;
}
/* get the destination keyring if specified */
dest = NULL;
if (destringid) {
dest = lookup_user_key(destringid, 1, 0, KEY_WRITE);
if (IS_ERR(dest)) {
ret = PTR_ERR(dest);
goto error3;
}
}
/* find the key type */
ktype = key_type_lookup(type);
if (IS_ERR(ktype)) {
ret = PTR_ERR(ktype);
goto error4;
}
/* do the search */
key = keyring_search(keyring, ktype, description);
if (IS_ERR(key)) {
ret = PTR_ERR(key);
/* treat lack or presence of a negative key the same */
if (ret == -EAGAIN)
ret = -ENOKEY;
goto error5;
}
/* link the resulting key to the destination keyring if we can */
if (dest) {
ret = -EACCES;
if (!key_permission(key, KEY_LINK))
goto error6;
ret = key_link(dest, key);
if (ret < 0)
goto error6;
}
ret = key->serial;
error6:
key_put(key);
error5:
key_type_put(ktype);
error4:
key_put(dest);
error3:
key_put(keyring);
error2:
kfree(description);
error:
return ret;
} /* end keyctl_keyring_search() */
/*****************************************************************************/
/*
* see if the key we're looking at is the target key
*/
static int keyctl_read_key_same(const struct key *key, const void *target)
{
return key == target;
} /* end keyctl_read_key_same() */
/*****************************************************************************/
/*
* read a user key's payload
* - the keyring must be readable or the key must be searchable from the
* process's keyrings
* - if there's a buffer, we place up to buflen bytes of data into it
* - unless there's an error, we return the amount of data in the key,
* irrespective of how much we may have copied
* - implements keyctl(KEYCTL_READ)
*/
long keyctl_read_key(key_serial_t keyid, char __user *buffer, size_t buflen)
{
struct key *key, *skey;
long ret;
/* find the key first */
key = lookup_user_key(keyid, 0, 0, 0);
if (!IS_ERR(key)) {
/* see if we can read it directly */
if (key_permission(key, KEY_READ))
goto can_read_key;
/* can't; see if it's searchable from this process's
* keyrings */
ret = -ENOKEY;
if (key_permission(key, KEY_SEARCH)) {
/* okay - we do have search permission on the key
* itself, but do we have the key? */
skey = search_process_keyrings_aux(key->type, key,
keyctl_read_key_same);
if (!IS_ERR(skey))
goto can_read_key2;
}
goto error2;
}
ret = -ENOKEY;
goto error;
/* the key is probably readable - now try to read it */
can_read_key2:
key_put(skey);
can_read_key:
ret = key_validate(key);
if (ret == 0) {
ret = -EOPNOTSUPP;
if (key->type->read) {
/* read the data with the semaphore held (since we
* might sleep) */
down_read(&key->sem);
ret = key->type->read(key, buffer, buflen);
up_read(&key->sem);
}
}
error2:
key_put(key);
error:
return ret;
} /* end keyctl_read_key() */
/*****************************************************************************/
/*
* change the ownership of a key
* - the keyring owned by the changer
* - if the uid or gid is -1, then that parameter is not changed
* - implements keyctl(KEYCTL_CHOWN)
*/
long keyctl_chown_key(key_serial_t id, uid_t uid, gid_t gid)
{
struct key *key;
long ret;
ret = 0;
if (uid == (uid_t) -1 && gid == (gid_t) -1)
goto error;
key = lookup_user_key(id, 1, 1, 0);
if (IS_ERR(key)) {
ret = PTR_ERR(key);
goto error;
}
/* make the changes with the locks held to prevent chown/chown races */
ret = -EACCES;
down_write(&key->sem);
write_lock(&key->lock);
if (!capable(CAP_SYS_ADMIN)) {
/* only the sysadmin can chown a key to some other UID */
if (uid != (uid_t) -1 && key->uid != uid)
goto no_access;
/* only the sysadmin can set the key's GID to a group other
* than one of those that the current process subscribes to */
if (gid != (gid_t) -1 && gid != key->gid && !in_group_p(gid))
goto no_access;
}
/* change the UID (have to update the quotas) */
if (uid != (uid_t) -1 && uid != key->uid) {
/* don't support UID changing yet */
ret = -EOPNOTSUPP;
goto no_access;
}
/* change the GID */
if (gid != (gid_t) -1)
key->gid = gid;
ret = 0;
no_access:
write_unlock(&key->lock);
up_write(&key->sem);
key_put(key);
error:
return ret;
} /* end keyctl_chown_key() */
/*****************************************************************************/
/*
* change the permission mask on a key
* - the keyring owned by the changer
* - implements keyctl(KEYCTL_SETPERM)
*/
long keyctl_setperm_key(key_serial_t id, key_perm_t perm)
{
struct key *key;
long ret;
ret = -EINVAL;
if (perm & ~(KEY_USR_ALL | KEY_GRP_ALL | KEY_OTH_ALL))
goto error;
key = lookup_user_key(id, 1, 1, 0);
if (IS_ERR(key)) {
ret = PTR_ERR(key);
goto error;
}
/* make the changes with the locks held to prevent chown/chmod
* races */
ret = -EACCES;
down_write(&key->sem);
write_lock(&key->lock);
/* if we're not the sysadmin, we can only chmod a key that we
* own */
if (!capable(CAP_SYS_ADMIN) && key->uid != current->fsuid)
goto no_access;
/* changing the permissions mask */
key->perm = perm;
ret = 0;
no_access:
write_unlock(&key->lock);
up_write(&key->sem);
key_put(key);
error:
return ret;
} /* end keyctl_setperm_key() */
/*****************************************************************************/
/*
* instantiate the key with the specified payload, and, if one is given, link
* the key into the keyring
*/
long keyctl_instantiate_key(key_serial_t id,
const void __user *_payload,
size_t plen,
key_serial_t ringid)
{
struct key *key, *keyring;
void *payload;
long ret;
ret = -EINVAL;
if (plen > 32767)
goto error;
/* pull the payload in if one was supplied */
payload = NULL;
if (_payload) {
ret = -ENOMEM;
payload = kmalloc(plen, GFP_KERNEL);
if (!payload)
goto error;
ret = -EFAULT;
if (copy_from_user(payload, _payload, plen) != 0)
goto error2;
}
/* find the target key (which must be writable) */
key = lookup_user_key(id, 0, 1, KEY_WRITE);
if (IS_ERR(key)) {
ret = PTR_ERR(key);
goto error2;
}
/* find the destination keyring if present (which must also be
* writable) */
keyring = NULL;
if (ringid) {
keyring = lookup_user_key(ringid, 1, 0, KEY_WRITE);
if (IS_ERR(keyring)) {
ret = PTR_ERR(keyring);
goto error3;
}
}
/* instantiate the key and link it into a keyring */
ret = key_instantiate_and_link(key, payload, plen, keyring);
key_put(keyring);
error3:
key_put(key);
error2:
kfree(payload);
error:
return ret;
} /* end keyctl_instantiate_key() */
/*****************************************************************************/
/*
* negatively instantiate the key with the given timeout (in seconds), and, if
* one is given, link the key into the keyring
*/
long keyctl_negate_key(key_serial_t id, unsigned timeout, key_serial_t ringid)
{
struct key *key, *keyring;
long ret;
/* find the target key (which must be writable) */
key = lookup_user_key(id, 0, 1, KEY_WRITE);
if (IS_ERR(key)) {
ret = PTR_ERR(key);
goto error;
}
/* find the destination keyring if present (which must also be
* writable) */
keyring = NULL;
if (ringid) {
keyring = lookup_user_key(ringid, 1, 0, KEY_WRITE);
if (IS_ERR(keyring)) {
ret = PTR_ERR(keyring);
goto error2;
}
}
/* instantiate the key and link it into a keyring */
ret = key_negate_and_link(key, timeout, keyring);
key_put(keyring);
error2:
key_put(key);
error:
return ret;
} /* end keyctl_negate_key() */
/*****************************************************************************/
/*
* the key control system call
*/
asmlinkage long sys_keyctl(int option, unsigned long arg2, unsigned long arg3,
unsigned long arg4, unsigned long arg5)
{
switch (option) {
case KEYCTL_GET_KEYRING_ID:
return keyctl_get_keyring_ID((key_serial_t) arg2,
(int) arg3);
case KEYCTL_JOIN_SESSION_KEYRING:
return keyctl_join_session_keyring((const char __user *) arg2);
case KEYCTL_UPDATE:
return keyctl_update_key((key_serial_t) arg2,
(const void __user *) arg3,
(size_t) arg4);
case KEYCTL_REVOKE:
return keyctl_revoke_key((key_serial_t) arg2);
case KEYCTL_DESCRIBE:
return keyctl_describe_key((key_serial_t) arg2,
(char __user *) arg3,
(unsigned) arg4);
case KEYCTL_CLEAR:
return keyctl_keyring_clear((key_serial_t) arg2);
case KEYCTL_LINK:
return keyctl_keyring_link((key_serial_t) arg2,
(key_serial_t) arg3);
case KEYCTL_UNLINK:
return keyctl_keyring_unlink((key_serial_t) arg2,
(key_serial_t) arg3);
case KEYCTL_SEARCH:
return keyctl_keyring_search((key_serial_t) arg2,
(const char __user *) arg3,
(const char __user *) arg4,
(key_serial_t) arg5);
case KEYCTL_READ:
return keyctl_read_key((key_serial_t) arg2,
(char __user *) arg3,
(size_t) arg4);
case KEYCTL_CHOWN:
return keyctl_chown_key((key_serial_t) arg2,
(uid_t) arg3,
(gid_t) arg4);
case KEYCTL_SETPERM:
return keyctl_setperm_key((key_serial_t) arg2,
(key_perm_t) arg3);
case KEYCTL_INSTANTIATE:
return keyctl_instantiate_key((key_serial_t) arg2,
(const void __user *) arg3,
(size_t) arg4,
(key_serial_t) arg5);
case KEYCTL_NEGATE:
return keyctl_negate_key((key_serial_t) arg2,
(unsigned) arg3,
(key_serial_t) arg4);
default:
return -EOPNOTSUPP;
}
} /* end sys_keyctl() */
