net/rxrpc/ar-security.c

   1 /* RxRPC security handling
   2  *
   3  * Copyright (C) 2007 Red Hat, Inc. All Rights Reserved.
   4  * Written by David Howells (dhowells@redhat.com)
   5  *
   6  * This program is free software; you can redistribute it and/or
   7  * modify it under the terms of the GNU General Public License
   8  * as published by the Free Software Foundation; either version
   9  * 2 of the License, or (at your option) any later version.
  10  */
  11
  12 #include <linux/module.h>
  13 #include <linux/net.h>
  14 #include <linux/skbuff.h>
  15 #include <linux/udp.h>
  16 #include <linux/crypto.h>
  17 #include <net/sock.h>
  18 #include <net/af_rxrpc.h>
  19 #include <keys/rxrpc-type.h>
  20 #include "ar-internal.h"
  21
  22 static LIST_HEAD(rxrpc_security_methods);
  23 static DECLARE_RWSEM(rxrpc_security_sem);
  24
  25 /*
  26  * get an RxRPC security module
  27  */
  28 static struct rxrpc_security *rxrpc_security_get(struct rxrpc_security *sec)
  29 {
  30         return try_module_get(sec->owner) ? sec : NULL;
  31 }
  32
  33 /*
  34  * release an RxRPC security module
  35  */
  36 static void rxrpc_security_put(struct rxrpc_security *sec)
  37 {
  38         module_put(sec->owner);
  39 }
  40
  41 /*
  42  * look up an rxrpc security module
  43  */
  44 static struct rxrpc_security *rxrpc_security_lookup(u8 security_index)
  45 {
  46         struct rxrpc_security *sec = NULL;
  47
  48         _enter("");
  49
  50         down_read(&rxrpc_security_sem);
  51
  52         list_for_each_entry(sec, &rxrpc_security_methods, link) {
  53                 if (sec->security_index == security_index) {
  54                         if (unlikely(!rxrpc_security_get(sec)))
  55                                 break;
  56                         goto out;
  57                 }
  58         }
  59
  60         sec = NULL;
  61 out:
  62         up_read(&rxrpc_security_sem);
  63         _leave(" = %p [%s]", sec, sec ? sec->name : "");
  64         return sec;
  65 }
  66
  67 /**
  68  * rxrpc_register_security - register an RxRPC security handler
  69  * @sec: security module
  70  *
  71  * register an RxRPC security handler for use by RxRPC
  72  */
  73 int rxrpc_register_security(struct rxrpc_security *sec)
  74 {
  75         struct rxrpc_security *psec;
  76         int ret;
  77
  78         _enter("");
  79         down_write(&rxrpc_security_sem);
  80
  81         ret = -EEXIST;
  82         list_for_each_entry(psec, &rxrpc_security_methods, link) {
  83                 if (psec->security_index == sec->security_index)
  84                         goto out;
  85         }
  86
  87         list_add(&sec->link, &rxrpc_security_methods);
  88
  89         printk(KERN_NOTICE "RxRPC: Registered security type %d '%s'\n",
  90                sec->security_index, sec->name);
  91         ret = 0;
  92
  93 out:
  94         up_write(&rxrpc_security_sem);
  95         _leave(" = %d", ret);
  96         return ret;
  97 }
  98
  99 EXPORT_SYMBOL_GPL(rxrpc_register_security);
 100
 101 /**
 102  * rxrpc_unregister_security - unregister an RxRPC security handler
 103  * @sec: security module
 104  *
 105  * unregister an RxRPC security handler
 106  */
 107 void rxrpc_unregister_security(struct rxrpc_security *sec)
 108 {
 109
 110         _enter("");
 111         down_write(&rxrpc_security_sem);
 112         list_del_init(&sec->link);
 113         up_write(&rxrpc_security_sem);
 114
 115         printk(KERN_NOTICE "RxRPC: Unregistered security type %d '%s'\n",
 116                sec->security_index, sec->name);
 117 }
 118
 119 EXPORT_SYMBOL_GPL(rxrpc_unregister_security);
 120
 121 /*
 122  * initialise the security on a client connection
 123  */
 124 int rxrpc_init_client_conn_security(struct rxrpc_connection *conn)
 125 {
 126         struct rxrpc_key_token *token;
 127         struct rxrpc_security *sec;
 128         struct key *key = conn->key;
 129         int ret;
 130
 131         _enter("{%d},{%x}", conn->debug_id, key_serial(key));
 132
 133         if (!key)
 134                 return 0;
 135
 136         ret = key_validate(key);
 137         if (ret < 0)
 138                 return ret;
 139
 140         token = key->payload.data[0];
 141         if (!token)
 142                 return -EKEYREJECTED;
 143
 144         sec = rxrpc_security_lookup(token->security_index);
 145         if (!sec)
 146                 return -EKEYREJECTED;
 147         conn->security = sec;
 148
 149         ret = conn->security->init_connection_security(conn);
 150         if (ret < 0) {
 151                 rxrpc_security_put(conn->security);
 152                 conn->security = NULL;
 153                 return ret;
 154         }
 155
 156         _leave(" = 0");
 157         return 0;
 158 }
 159
 160 /*
 161  * initialise the security on a server connection
 162  */
 163 int rxrpc_init_server_conn_security(struct rxrpc_connection *conn)
 164 {
 165         struct rxrpc_security *sec;
 166         struct rxrpc_local *local = conn->trans->local;
 167         struct rxrpc_sock *rx;
 168         struct key *key;
 169         key_ref_t kref;
 170         char kdesc[5+1+3+1];
 171
 172         _enter("");
 173
 174         sprintf(kdesc, "%u:%u", ntohs(conn->service_id), conn->security_ix);
 175
 176         sec = rxrpc_security_lookup(conn->security_ix);
 177         if (!sec) {
 178                 _leave(" = -ENOKEY [lookup]");
 179                 return -ENOKEY;
 180         }
 181
 182         /* find the service */
 183         read_lock_bh(&local->services_lock);
 184         list_for_each_entry(rx, &local->services, listen_link) {
 185                 if (rx->service_id == conn->service_id)
 186                         goto found_service;
 187         }
 188
 189         /* the service appears to have died */
 190         read_unlock_bh(&local->services_lock);
 191         rxrpc_security_put(sec);
 192         _leave(" = -ENOENT");
 193         return -ENOENT;
 194
 195 found_service:
 196         if (!rx->securities) {
 197                 read_unlock_bh(&local->services_lock);
 198                 rxrpc_security_put(sec);
 199                 _leave(" = -ENOKEY");
 200                 return -ENOKEY;
 201         }
 202
 203         /* look through the service's keyring */
 204         kref = keyring_search(make_key_ref(rx->securities, 1UL),
 205                               &key_type_rxrpc_s, kdesc);
 206         if (IS_ERR(kref)) {
 207                 read_unlock_bh(&local->services_lock);
 208                 rxrpc_security_put(sec);
 209                 _leave(" = %ld [search]", PTR_ERR(kref));
 210                 return PTR_ERR(kref);
 211         }
 212
 213         key = key_ref_to_ptr(kref);
 214         read_unlock_bh(&local->services_lock);
 215
 216         conn->server_key = key;
 217         conn->security = sec;
 218
 219         _leave(" = 0");
 220         return 0;
 221 }
 222
 223 /*
 224  * secure a packet prior to transmission
 225  */
 226 int rxrpc_secure_packet(const struct rxrpc_call *call,
 227                         struct sk_buff *skb,
 228                         size_t data_size,
 229                         void *sechdr)
 230 {
 231         if (call->conn->security)
 232                 return call->conn->security->secure_packet(
 233                         call, skb, data_size, sechdr);
 234         return 0;
 235 }
 236
 237 /*
 238  * secure a packet prior to transmission
 239  */
 240 int rxrpc_verify_packet(const struct rxrpc_call *call, struct sk_buff *skb,
 241                         u32 *_abort_code)
 242 {
 243         if (call->conn->security)
 244                 return call->conn->security->verify_packet(
 245                         call, skb, _abort_code);
 246         return 0;
 247 }
 248
 249 /*
 250  * clear connection security
 251  */
 252 void rxrpc_clear_conn_security(struct rxrpc_connection *conn)
 253 {
 254         _enter("{%d}", conn->debug_id);
 255
 256         if (conn->security) {
 257                 conn->security->clear(conn);
 258                 rxrpc_security_put(conn->security);
 259                 conn->security = NULL;
 260         }
 261
 262         key_put(conn->key);
 263         key_put(conn->server_key);
 264 }