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