linux/net/rxrpc/ar-key.c
David Howells 76181c134f KEYS: Make request_key() and co fundamentally asynchronous
Make request_key() and co fundamentally asynchronous to make it easier for
NFS to make use of them.  There are now accessor functions that do
asynchronous constructions, a wait function to wait for construction to
complete, and a completion function for the key type to indicate completion
of construction.

Note that the construction queue is now gone.  Instead, keys under
construction are linked in to the appropriate keyring in advance, and that
anyone encountering one must wait for it to be complete before they can use
it.  This is done automatically for userspace.

The following auxiliary changes are also made:

 (1) Key type implementation stuff is split from linux/key.h into
     linux/key-type.h.

 (2) AF_RXRPC provides a way to allocate null rxrpc-type keys so that AFS does
     not need to call key_instantiate_and_link() directly.

 (3) Adjust the debugging macros so that they're -Wformat checked even if
     they are disabled, and make it so they can be enabled simply by defining
     __KDEBUG to be consistent with other code of mine.

 (3) Documentation.

[alan@lxorguk.ukuu.org.uk: keys: missing word in documentation]
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Alan Cox <alan@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-10-17 08:42:57 -07:00

360 lines
8 KiB
C

/* RxRPC key management
*
* Copyright (C) 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
* 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.
*
* RxRPC keys should have a description of describing their purpose:
* "afs@CAMBRIDGE.REDHAT.COM>
*/
#include <linux/module.h>
#include <linux/net.h>
#include <linux/skbuff.h>
#include <linux/key-type.h>
#include <linux/crypto.h>
#include <net/sock.h>
#include <net/af_rxrpc.h>
#include <keys/rxrpc-type.h>
#include <keys/user-type.h>
#include "ar-internal.h"
static int rxrpc_instantiate(struct key *, const void *, size_t);
static int rxrpc_instantiate_s(struct key *, const void *, size_t);
static void rxrpc_destroy(struct key *);
static void rxrpc_destroy_s(struct key *);
static void rxrpc_describe(const struct key *, struct seq_file *);
/*
* rxrpc defined keys take an arbitrary string as the description and an
* arbitrary blob of data as the payload
*/
struct key_type key_type_rxrpc = {
.name = "rxrpc",
.instantiate = rxrpc_instantiate,
.match = user_match,
.destroy = rxrpc_destroy,
.describe = rxrpc_describe,
};
EXPORT_SYMBOL(key_type_rxrpc);
/*
* rxrpc server defined keys take "<serviceId>:<securityIndex>" as the
* description and an 8-byte decryption key as the payload
*/
struct key_type key_type_rxrpc_s = {
.name = "rxrpc_s",
.instantiate = rxrpc_instantiate_s,
.match = user_match,
.destroy = rxrpc_destroy_s,
.describe = rxrpc_describe,
};
/*
* instantiate an rxrpc defined key
* data should be of the form:
* OFFSET LEN CONTENT
* 0 4 key interface version number
* 4 2 security index (type)
* 6 2 ticket length
* 8 4 key expiry time (time_t)
* 12 4 kvno
* 16 8 session key
* 24 [len] ticket
*
* if no data is provided, then a no-security key is made
*/
static int rxrpc_instantiate(struct key *key, const void *data, size_t datalen)
{
const struct rxkad_key *tsec;
struct rxrpc_key_payload *upayload;
size_t plen;
u32 kver;
int ret;
_enter("{%x},,%zu", key_serial(key), datalen);
/* handle a no-security key */
if (!data && datalen == 0)
return 0;
/* get the key interface version number */
ret = -EINVAL;
if (datalen <= 4 || !data)
goto error;
memcpy(&kver, data, sizeof(kver));
data += sizeof(kver);
datalen -= sizeof(kver);
_debug("KEY I/F VERSION: %u", kver);
ret = -EKEYREJECTED;
if (kver != 1)
goto error;
/* deal with a version 1 key */
ret = -EINVAL;
if (datalen < sizeof(*tsec))
goto error;
tsec = data;
if (datalen != sizeof(*tsec) + tsec->ticket_len)
goto error;
_debug("SCIX: %u", tsec->security_index);
_debug("TLEN: %u", tsec->ticket_len);
_debug("EXPY: %x", tsec->expiry);
_debug("KVNO: %u", tsec->kvno);
_debug("SKEY: %02x%02x%02x%02x%02x%02x%02x%02x",
tsec->session_key[0], tsec->session_key[1],
tsec->session_key[2], tsec->session_key[3],
tsec->session_key[4], tsec->session_key[5],
tsec->session_key[6], tsec->session_key[7]);
if (tsec->ticket_len >= 8)
_debug("TCKT: %02x%02x%02x%02x%02x%02x%02x%02x",
tsec->ticket[0], tsec->ticket[1],
tsec->ticket[2], tsec->ticket[3],
tsec->ticket[4], tsec->ticket[5],
tsec->ticket[6], tsec->ticket[7]);
ret = -EPROTONOSUPPORT;
if (tsec->security_index != 2)
goto error;
key->type_data.x[0] = tsec->security_index;
plen = sizeof(*upayload) + tsec->ticket_len;
ret = key_payload_reserve(key, plen);
if (ret < 0)
goto error;
ret = -ENOMEM;
upayload = kmalloc(plen, GFP_KERNEL);
if (!upayload)
goto error;
/* attach the data */
memcpy(&upayload->k, tsec, sizeof(*tsec));
memcpy(&upayload->k.ticket, (void *)tsec + sizeof(*tsec),
tsec->ticket_len);
key->payload.data = upayload;
key->expiry = tsec->expiry;
ret = 0;
error:
return ret;
}
/*
* instantiate a server secret key
* data should be a pointer to the 8-byte secret key
*/
static int rxrpc_instantiate_s(struct key *key, const void *data,
size_t datalen)
{
struct crypto_blkcipher *ci;
_enter("{%x},,%zu", key_serial(key), datalen);
if (datalen != 8)
return -EINVAL;
memcpy(&key->type_data, data, 8);
ci = crypto_alloc_blkcipher("pcbc(des)", 0, CRYPTO_ALG_ASYNC);
if (IS_ERR(ci)) {
_leave(" = %ld", PTR_ERR(ci));
return PTR_ERR(ci);
}
if (crypto_blkcipher_setkey(ci, data, 8) < 0)
BUG();
key->payload.data = ci;
_leave(" = 0");
return 0;
}
/*
* dispose of the data dangling from the corpse of a rxrpc key
*/
static void rxrpc_destroy(struct key *key)
{
kfree(key->payload.data);
}
/*
* dispose of the data dangling from the corpse of a rxrpc key
*/
static void rxrpc_destroy_s(struct key *key)
{
if (key->payload.data) {
crypto_free_blkcipher(key->payload.data);
key->payload.data = NULL;
}
}
/*
* describe the rxrpc key
*/
static void rxrpc_describe(const struct key *key, struct seq_file *m)
{
seq_puts(m, key->description);
}
/*
* grab the security key for a socket
*/
int rxrpc_request_key(struct rxrpc_sock *rx, char __user *optval, int optlen)
{
struct key *key;
char *description;
_enter("");
if (optlen <= 0 || optlen > PAGE_SIZE - 1)
return -EINVAL;
description = kmalloc(optlen + 1, GFP_KERNEL);
if (!description)
return -ENOMEM;
if (copy_from_user(description, optval, optlen)) {
kfree(description);
return -EFAULT;
}
description[optlen] = 0;
key = request_key(&key_type_rxrpc, description, NULL);
if (IS_ERR(key)) {
kfree(description);
_leave(" = %ld", PTR_ERR(key));
return PTR_ERR(key);
}
rx->key = key;
kfree(description);
_leave(" = 0 [key %x]", key->serial);
return 0;
}
/*
* grab the security keyring for a server socket
*/
int rxrpc_server_keyring(struct rxrpc_sock *rx, char __user *optval,
int optlen)
{
struct key *key;
char *description;
_enter("");
if (optlen <= 0 || optlen > PAGE_SIZE - 1)
return -EINVAL;
description = kmalloc(optlen + 1, GFP_KERNEL);
if (!description)
return -ENOMEM;
if (copy_from_user(description, optval, optlen)) {
kfree(description);
return -EFAULT;
}
description[optlen] = 0;
key = request_key(&key_type_keyring, description, NULL);
if (IS_ERR(key)) {
kfree(description);
_leave(" = %ld", PTR_ERR(key));
return PTR_ERR(key);
}
rx->securities = key;
kfree(description);
_leave(" = 0 [key %x]", key->serial);
return 0;
}
/*
* generate a server data key
*/
int rxrpc_get_server_data_key(struct rxrpc_connection *conn,
const void *session_key,
time_t expiry,
u32 kvno)
{
struct key *key;
int ret;
struct {
u32 kver;
struct rxkad_key tsec;
} data;
_enter("");
key = key_alloc(&key_type_rxrpc, "x", 0, 0, current, 0,
KEY_ALLOC_NOT_IN_QUOTA);
if (IS_ERR(key)) {
_leave(" = -ENOMEM [alloc %ld]", PTR_ERR(key));
return -ENOMEM;
}
_debug("key %d", key_serial(key));
data.kver = 1;
data.tsec.security_index = 2;
data.tsec.ticket_len = 0;
data.tsec.expiry = expiry;
data.tsec.kvno = 0;
memcpy(&data.tsec.session_key, session_key,
sizeof(data.tsec.session_key));
ret = key_instantiate_and_link(key, &data, sizeof(data), NULL, NULL);
if (ret < 0)
goto error;
conn->key = key;
_leave(" = 0 [%d]", key_serial(key));
return 0;
error:
key_revoke(key);
key_put(key);
_leave(" = -ENOMEM [ins %d]", ret);
return -ENOMEM;
}
EXPORT_SYMBOL(rxrpc_get_server_data_key);
/**
* rxrpc_get_null_key - Generate a null RxRPC key
* @keyname: The name to give the key.
*
* Generate a null RxRPC key that can be used to indicate anonymous security is
* required for a particular domain.
*/
struct key *rxrpc_get_null_key(const char *keyname)
{
struct key *key;
int ret;
key = key_alloc(&key_type_rxrpc, keyname, 0, 0, current,
KEY_POS_SEARCH, KEY_ALLOC_NOT_IN_QUOTA);
if (IS_ERR(key))
return key;
ret = key_instantiate_and_link(key, NULL, 0, NULL, NULL);
if (ret < 0) {
key_revoke(key);
key_put(key);
return ERR_PTR(ret);
}
return key;
}
EXPORT_SYMBOL(rxrpc_get_null_key);