// SPDX-License-Identifier: GPL-2.0-or-later
/* RxRPC security handling
 *
 * Copyright (C) 2007 Red Hat, Inc. All Rights Reserved.
 * Written by David Howells (dhowells@redhat.com)
 */

#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 const struct rxrpc_security *rxrpc_security_types[] = {
        [RXRPC_SECURITY_NONE]   = &rxrpc_no_security,
#ifdef CONFIG_RXKAD
        [RXRPC_SECURITY_RXKAD]  = &rxkad,
#endif
#ifdef CONFIG_RXGK
        [RXRPC_SECURITY_YFS_RXGK] = &rxgk_yfs,
#endif
};

int __init rxrpc_init_security(void)
{
        int i, ret;

        for (i = 0; i < ARRAY_SIZE(rxrpc_security_types); i++) {
                if (rxrpc_security_types[i]) {
                        ret = rxrpc_security_types[i]->init();
                        if (ret < 0)
                                goto failed;
                }
        }

        return 0;

failed:
        for (i--; i >= 0; i--)
                if (rxrpc_security_types[i])
                        rxrpc_security_types[i]->exit();
        return ret;
}

void rxrpc_exit_security(void)
{
        int i;

        for (i = 0; i < ARRAY_SIZE(rxrpc_security_types); i++)
                if (rxrpc_security_types[i])
                        rxrpc_security_types[i]->exit();
}

/*
 * look up an rxrpc security module
 */
const struct rxrpc_security *rxrpc_security_lookup(u8 security_index)
{
        if (security_index >= ARRAY_SIZE(rxrpc_security_types))
                return NULL;
        return rxrpc_security_types[security_index];
}

/*
 * Initialise the security on a client call.
 */
int rxrpc_init_client_call_security(struct rxrpc_call *call)
{
        const struct rxrpc_security *sec = &rxrpc_no_security;
        struct rxrpc_key_token *token;
        struct key *key = call->key;
        int ret;

        if (!key)
                goto found;

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

        for (token = key->payload.data[0]; token; token = token->next) {
                sec = rxrpc_security_lookup(token->security_index);
                if (sec)
                        goto found;
        }
        return -EKEYREJECTED;

found:
        call->security = sec;
        call->security_ix = sec->security_index;
        return 0;
}

/*
 * initialise the security on a client connection
 */
int rxrpc_init_client_conn_security(struct rxrpc_connection *conn)
{
        struct rxrpc_key_token *token;
        struct key *key = conn->key;
        int ret = 0;

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

        for (token = key->payload.data[0]; token; token = token->next) {
                if (token->security_index == conn->security->security_index)
                        goto found;
        }
        return -EKEYREJECTED;

found:
        mutex_lock(&conn->security_lock);
        if (conn->state == RXRPC_CONN_CLIENT_UNSECURED) {
                ret = conn->security->init_connection_security(conn, token);
                if (ret == 0) {
                        spin_lock_irq(&conn->state_lock);
                        if (conn->state == RXRPC_CONN_CLIENT_UNSECURED)
                                conn->state = RXRPC_CONN_CLIENT;
                        spin_unlock_irq(&conn->state_lock);
                }
        }
        mutex_unlock(&conn->security_lock);
        return ret;
}

/*
 * Set the ops a server connection.
 */
const struct rxrpc_security *rxrpc_get_incoming_security(struct rxrpc_sock *rx,
                                                         struct sk_buff *skb)
{
        const struct rxrpc_security *sec;
        struct rxrpc_skb_priv *sp = rxrpc_skb(skb);

        _enter("");

        sec = rxrpc_security_lookup(sp->hdr.securityIndex);
        if (!sec) {
                rxrpc_direct_conn_abort(skb, rxrpc_abort_unsupported_security,
                                        RX_INVALID_OPERATION, -EKEYREJECTED);
                return NULL;
        }

        if (sp->hdr.securityIndex != RXRPC_SECURITY_NONE &&
            !rx->securities) {
                rxrpc_direct_conn_abort(skb, rxrpc_abort_no_service_key,
                                        sec->no_key_abort, -EKEYREJECTED);
                return NULL;
        }

        return sec;
}

/*
 * Find the security key for a server connection.
 */
struct key *rxrpc_look_up_server_security(struct rxrpc_connection *conn,
                                          struct sk_buff *skb,
                                          u32 kvno, u32 enctype)
{
        struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
        struct rxrpc_sock *rx;
        struct key *key = ERR_PTR(-EKEYREJECTED);
        key_ref_t kref = NULL;
        char kdesc[5 + 1 + 3 + 1 + 12 + 1 + 12 + 1];
        int ret;

        _enter("");

        if (enctype)
                sprintf(kdesc, "%u:%u:%u:%u",
                        sp->hdr.serviceId, sp->hdr.securityIndex, kvno, enctype);
        else if (kvno)
                sprintf(kdesc, "%u:%u:%u",
                        sp->hdr.serviceId, sp->hdr.securityIndex, kvno);
        else
                sprintf(kdesc, "%u:%u",
                        sp->hdr.serviceId, sp->hdr.securityIndex);

        read_lock(&conn->local->services_lock);

        rx = conn->local->service;
        if (!rx)
                goto out;

        /* look through the service's keyring */
        kref = keyring_search(make_key_ref(rx->securities, 1UL),
                              &key_type_rxrpc_s, kdesc, true);
        if (IS_ERR(kref)) {
                key = ERR_CAST(kref);
                goto out;
        }

        key = key_ref_to_ptr(kref);

        ret = key_validate(key);
        if (ret < 0) {
                key_put(key);
                key = ERR_PTR(ret);
                goto out;
        }

out:
        read_unlock(&conn->local->services_lock);
        return key;
}