ar-security.c

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/* RxRPC security handling
 *
 * Copyright (C) 2007 Red Hat, Inc. All Rights Reserved.
 * Written by David Howells ([email protected])
 *
 * 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/net.h>
#include <linux/skbuff.h>
#include <linux/udp.h>
#include <linux/crypto.h>
#include <net/sock.h>
#include <net/af_rxrpc.h>
#include <keys/rxrpc-type.h>
#include "ar-internal.h"

static LIST_HEAD(rxrpc_security_methods);
static DECLARE_RWSEM(rxrpc_security_sem);

/*
 * get an RxRPC security module
 */
static struct rxrpc_security *rxrpc_security_get(struct rxrpc_security *sec)
{
    return try_module_get(sec->owner) ? sec : NULL;
}

/*
 * release an RxRPC security module
 */
static void rxrpc_security_put(struct rxrpc_security *sec)
{
    module_put(sec->owner);
}

/*
 * look up an rxrpc security module
 */
static struct rxrpc_security *rxrpc_security_lookup(u8 security_index)
{
    struct rxrpc_security *sec = NULL;

    _enter("");

    down_read(&rxrpc_security_sem);

    list_for_each_entry(sec, &rxrpc_security_methods, link) {
        if (sec->security_index == security_index) {
            if (unlikely(!rxrpc_security_get(sec)))
                break;
            goto out;
        }
    }

    sec = NULL;
out:
    up_read(&rxrpc_security_sem);
    _leave(" = %p [%s]", sec, sec ? sec->name : "");
    return sec;
}

int rxrpc_register_security(struct rxrpc_security *sec)
{
    struct rxrpc_security *psec;
    int ret;

    _enter("");
    down_write(&rxrpc_security_sem);

    ret = -EEXIST;
    list_for_each_entry(psec, &rxrpc_security_methods, link) {
        if (psec->security_index == sec->security_index)
            goto out;
    }

    list_add(&sec->link, &rxrpc_security_methods);

    printk(KERN_NOTICE "RxRPC: Registered security type %d '%s'\n",
           sec->security_index, sec->name);
    ret = 0;

out:
    up_write(&rxrpc_security_sem);
    _leave(" = %d", ret);
    return ret;
}

EXPORT_SYMBOL_GPL(rxrpc_register_security);

void rxrpc_unregister_security(struct rxrpc_security *sec)
{

    _enter("");
    down_write(&rxrpc_security_sem);
    list_del_init(&sec->link);
    up_write(&rxrpc_security_sem);

    printk(KERN_NOTICE "RxRPC: Unregistered security type %d '%s'\n",
           sec->security_index, sec->name);
}

EXPORT_SYMBOL_GPL(rxrpc_unregister_security);

/*
 * initialise the security on a client connection
 */
int rxrpc_init_client_conn_security(struct rxrpc_connection *conn)
{
    struct rxrpc_key_token *token;
    struct rxrpc_security *sec;
    struct key *key = conn->key;
    int ret;

    _enter("{%d},{%x}", conn->debug_id, key_serial(key));

    if (!key)
        return 0;

    ret = key_validate(key);
    if (ret < 0)
        return ret;

    if (!key->payload.data)
        return -EKEYREJECTED;
    token = key->payload.data;

    sec = rxrpc_security_lookup(token->security_index);
    if (!sec)
        return -EKEYREJECTED;
    conn->security = sec;

    ret = conn->security->init_connection_security(conn);
    if (ret < 0) {
        rxrpc_security_put(conn->security);
        conn->security = NULL;
        return ret;
    }

    _leave(" = 0");
    return 0;
}

/*
 * initialise the security on a server connection
 */
int rxrpc_init_server_conn_security(struct rxrpc_connection *conn)
{
    struct rxrpc_security *sec;
    struct rxrpc_local *local = conn->trans->local;
    struct rxrpc_sock *rx;
    struct key *key;
    key_ref_t kref;
    char kdesc[5+1+3+1];

    _enter("");

    sprintf(kdesc, "%u:%u", ntohs(conn->service_id), conn->security_ix);

    sec = rxrpc_security_lookup(conn->security_ix);
    if (!sec) {
        _leave(" = -ENOKEY [lookup]");
        return -ENOKEY;
    }

    /* find the service */
    read_lock_bh(&local->services_lock);
    list_for_each_entry(rx, &local->services, listen_link) {
        if (rx->service_id == conn->service_id)
            goto found_service;
    }

    /* the service appears to have died */
    read_unlock_bh(&local->services_lock);
    rxrpc_security_put(sec);
    _leave(" = -ENOENT");
    return -ENOENT;

found_service:
    if (!rx->securities) {
        read_unlock_bh(&local->services_lock);
        rxrpc_security_put(sec);
        _leave(" = -ENOKEY");
        return -ENOKEY;
    }

    /* look through the service's keyring */
    kref = keyring_search(make_key_ref(rx->securities, 1UL),
                  &key_type_rxrpc_s, kdesc);
    if (IS_ERR(kref)) {
        read_unlock_bh(&local->services_lock);
        rxrpc_security_put(sec);
        _leave(" = %ld [search]", PTR_ERR(kref));
        return PTR_ERR(kref);
    }

    key = key_ref_to_ptr(kref);
    read_unlock_bh(&local->services_lock);

    conn->server_key = key;
    conn->security = sec;

    _leave(" = 0");
    return 0;
}

/*
 * secure a packet prior to transmission
 */
int rxrpc_secure_packet(const struct rxrpc_call *call,
            struct sk_buff *skb,
            size_t data_size,
            void *sechdr)
{
    if (call->conn->security)
        return call->conn->security->secure_packet(
            call, skb, data_size, sechdr);
    return 0;
}

/*
 * secure a packet prior to transmission
 */
int rxrpc_verify_packet(const struct rxrpc_call *call, struct sk_buff *skb,
            u32 *_abort_code)
{
    if (call->conn->security)
        return call->conn->security->verify_packet(
            call, skb, _abort_code);
    return 0;
}

/*
 * clear connection security
 */
void rxrpc_clear_conn_security(struct rxrpc_connection *conn)
{
    _enter("{%d}", conn->debug_id);

    if (conn->security) {
        conn->security->clear(conn);
        rxrpc_security_put(conn->security);
        conn->security = NULL;
    }

    key_put(conn->key);
    key_put(conn->server_key);
}