1 /* License: GPL */ 2 3 #include <linux/filter.h> 4 #include <linux/mutex.h> 5 #include <linux/socket.h> 6 #include <linux/skbuff.h> 7 #include <net/netlink.h> 8 #include <net/net_namespace.h> 9 #include <linux/module.h> 10 #include <net/sock.h> 11 #include <linux/kernel.h> 12 #include <linux/tcp.h> 13 #include <linux/workqueue.h> 14 #include <linux/nospec.h> 15 #include <linux/cookie.h> 16 #include <linux/inet_diag.h> 17 #include <linux/sock_diag.h> 18 19 static const struct sock_diag_handler __rcu *sock_diag_handlers[AF_MAX]; 20 21 static struct sock_diag_inet_compat __rcu *inet_rcv_compat; 22 23 static struct workqueue_struct *broadcast_wq; 24 25 DEFINE_COOKIE(sock_cookie); 26 27 u64 __sock_gen_cookie(struct sock *sk) 28 { 29 u64 res = atomic64_read(&sk->sk_cookie); 30 31 if (!res) { 32 u64 new = gen_cookie_next(&sock_cookie); 33 34 atomic64_cmpxchg(&sk->sk_cookie, res, new); 35 36 /* Another thread might have changed sk_cookie before us. */ 37 res = atomic64_read(&sk->sk_cookie); 38 } 39 return res; 40 } 41 42 int sock_diag_check_cookie(struct sock *sk, const __u32 *cookie) 43 { 44 u64 res; 45 46 if (cookie[0] == INET_DIAG_NOCOOKIE && cookie[1] == INET_DIAG_NOCOOKIE) 47 return 0; 48 49 res = sock_gen_cookie(sk); 50 if ((u32)res != cookie[0] || (u32)(res >> 32) != cookie[1]) 51 return -ESTALE; 52 53 return 0; 54 } 55 EXPORT_SYMBOL_GPL(sock_diag_check_cookie); 56 57 void sock_diag_save_cookie(struct sock *sk, __u32 *cookie) 58 { 59 u64 res = sock_gen_cookie(sk); 60 61 cookie[0] = (u32)res; 62 cookie[1] = (u32)(res >> 32); 63 } 64 EXPORT_SYMBOL_GPL(sock_diag_save_cookie); 65 66 int sock_diag_put_meminfo(struct sock *sk, struct sk_buff *skb, int attrtype) 67 { 68 u32 mem[SK_MEMINFO_VARS]; 69 70 sk_get_meminfo(sk, mem); 71 72 return nla_put(skb, attrtype, sizeof(mem), &mem); 73 } 74 EXPORT_SYMBOL_GPL(sock_diag_put_meminfo); 75 76 int sock_diag_put_filterinfo(bool may_report_filterinfo, struct sock *sk, 77 struct sk_buff *skb, int attrtype) 78 { 79 struct sock_fprog_kern *fprog; 80 struct sk_filter *filter; 81 struct nlattr *attr; 82 unsigned int flen; 83 int err = 0; 84 85 if (!may_report_filterinfo) { 86 nla_reserve(skb, attrtype, 0); 87 return 0; 88 } 89 90 rcu_read_lock(); 91 filter = rcu_dereference(sk->sk_filter); 92 if (!filter) 93 goto out; 94 95 fprog = filter->prog->orig_prog; 96 if (!fprog) 97 goto out; 98 99 flen = bpf_classic_proglen(fprog); 100 101 attr = nla_reserve(skb, attrtype, flen); 102 if (attr == NULL) { 103 err = -EMSGSIZE; 104 goto out; 105 } 106 107 memcpy(nla_data(attr), fprog->filter, flen); 108 out: 109 rcu_read_unlock(); 110 return err; 111 } 112 EXPORT_SYMBOL(sock_diag_put_filterinfo); 113 114 struct broadcast_sk { 115 struct sock *sk; 116 struct work_struct work; 117 }; 118 119 static size_t sock_diag_nlmsg_size(void) 120 { 121 return NLMSG_ALIGN(sizeof(struct inet_diag_msg) 122 + nla_total_size(sizeof(u8)) /* INET_DIAG_PROTOCOL */ 123 + nla_total_size_64bit(sizeof(struct tcp_info))); /* INET_DIAG_INFO */ 124 } 125 126 static const struct sock_diag_handler *sock_diag_lock_handler(int family) 127 { 128 const struct sock_diag_handler *handler; 129 130 rcu_read_lock(); 131 handler = rcu_dereference(sock_diag_handlers[family]); 132 if (handler && !try_module_get(handler->owner)) 133 handler = NULL; 134 rcu_read_unlock(); 135 136 return handler; 137 } 138 139 static void sock_diag_unlock_handler(const struct sock_diag_handler *handler) 140 { 141 module_put(handler->owner); 142 } 143 144 static void sock_diag_broadcast_destroy_work(struct work_struct *work) 145 { 146 struct broadcast_sk *bsk = 147 container_of(work, struct broadcast_sk, work); 148 struct sock *sk = bsk->sk; 149 const struct sock_diag_handler *hndl; 150 struct sk_buff *skb; 151 const enum sknetlink_groups group = sock_diag_destroy_group(sk); 152 int err = -1; 153 154 WARN_ON(group == SKNLGRP_NONE); 155 156 skb = nlmsg_new(sock_diag_nlmsg_size(), GFP_KERNEL); 157 if (!skb) 158 goto out; 159 160 hndl = sock_diag_lock_handler(sk->sk_family); 161 if (hndl) { 162 if (hndl->get_info) 163 err = hndl->get_info(skb, sk); 164 sock_diag_unlock_handler(hndl); 165 } 166 if (!err) 167 nlmsg_multicast(sock_net(sk)->diag_nlsk, skb, 0, group, 168 GFP_KERNEL); 169 else 170 kfree_skb(skb); 171 out: 172 sk_destruct(sk); 173 kfree(bsk); 174 } 175 176 void sock_diag_broadcast_destroy(struct sock *sk) 177 { 178 /* Note, this function is often called from an interrupt context. */ 179 struct broadcast_sk *bsk = 180 kmalloc(sizeof(struct broadcast_sk), GFP_ATOMIC); 181 if (!bsk) 182 return sk_destruct(sk); 183 bsk->sk = sk; 184 INIT_WORK(&bsk->work, sock_diag_broadcast_destroy_work); 185 queue_work(broadcast_wq, &bsk->work); 186 } 187 188 void sock_diag_register_inet_compat(const struct sock_diag_inet_compat *ptr) 189 { 190 xchg((__force const struct sock_diag_inet_compat **)&inet_rcv_compat, 191 ptr); 192 } 193 EXPORT_SYMBOL_GPL(sock_diag_register_inet_compat); 194 195 void sock_diag_unregister_inet_compat(const struct sock_diag_inet_compat *ptr) 196 { 197 const struct sock_diag_inet_compat *old; 198 199 old = xchg((__force const struct sock_diag_inet_compat **)&inet_rcv_compat, 200 NULL); 201 WARN_ON_ONCE(old != ptr); 202 } 203 EXPORT_SYMBOL_GPL(sock_diag_unregister_inet_compat); 204 205 int sock_diag_register(const struct sock_diag_handler *hndl) 206 { 207 int family = hndl->family; 208 209 if (family >= AF_MAX) 210 return -EINVAL; 211 212 return !cmpxchg((const struct sock_diag_handler **) 213 &sock_diag_handlers[family], 214 NULL, hndl) ? 0 : -EBUSY; 215 } 216 EXPORT_SYMBOL_GPL(sock_diag_register); 217 218 void sock_diag_unregister(const struct sock_diag_handler *hndl) 219 { 220 int family = hndl->family; 221 222 if (family >= AF_MAX) 223 return; 224 225 xchg((const struct sock_diag_handler **)&sock_diag_handlers[family], 226 NULL); 227 } 228 EXPORT_SYMBOL_GPL(sock_diag_unregister); 229 230 static int __sock_diag_cmd(struct sk_buff *skb, struct nlmsghdr *nlh) 231 { 232 int err; 233 struct sock_diag_req *req = nlmsg_data(nlh); 234 const struct sock_diag_handler *hndl; 235 236 if (nlmsg_len(nlh) < sizeof(*req)) 237 return -EINVAL; 238 239 if (req->sdiag_family >= AF_MAX) 240 return -EINVAL; 241 req->sdiag_family = array_index_nospec(req->sdiag_family, AF_MAX); 242 243 if (!rcu_access_pointer(sock_diag_handlers[req->sdiag_family])) 244 sock_load_diag_module(req->sdiag_family, 0); 245 246 hndl = sock_diag_lock_handler(req->sdiag_family); 247 if (hndl == NULL) 248 return -ENOENT; 249 250 if (nlh->nlmsg_type == SOCK_DIAG_BY_FAMILY) 251 err = hndl->dump(skb, nlh); 252 else if (nlh->nlmsg_type == SOCK_DESTROY && hndl->destroy) 253 err = hndl->destroy(skb, nlh); 254 else 255 err = -EOPNOTSUPP; 256 sock_diag_unlock_handler(hndl); 257 258 return err; 259 } 260 261 static int sock_diag_rcv_msg(struct sk_buff *skb, struct nlmsghdr *nlh, 262 struct netlink_ext_ack *extack) 263 { 264 const struct sock_diag_inet_compat *ptr; 265 int ret; 266 267 switch (nlh->nlmsg_type) { 268 case TCPDIAG_GETSOCK: 269 case DCCPDIAG_GETSOCK: 270 271 if (!rcu_access_pointer(inet_rcv_compat)) 272 sock_load_diag_module(AF_INET, 0); 273 274 rcu_read_lock(); 275 ptr = rcu_dereference(inet_rcv_compat); 276 if (ptr && !try_module_get(ptr->owner)) 277 ptr = NULL; 278 rcu_read_unlock(); 279 280 ret = -EOPNOTSUPP; 281 if (ptr) { 282 ret = ptr->fn(skb, nlh); 283 module_put(ptr->owner); 284 } 285 286 return ret; 287 case SOCK_DIAG_BY_FAMILY: 288 case SOCK_DESTROY: 289 return __sock_diag_cmd(skb, nlh); 290 default: 291 return -EINVAL; 292 } 293 } 294 295 static void sock_diag_rcv(struct sk_buff *skb) 296 { 297 netlink_rcv_skb(skb, &sock_diag_rcv_msg); 298 } 299 300 static int sock_diag_bind(struct net *net, int group) 301 { 302 switch (group) { 303 case SKNLGRP_INET_TCP_DESTROY: 304 case SKNLGRP_INET_UDP_DESTROY: 305 if (!rcu_access_pointer(sock_diag_handlers[AF_INET])) 306 sock_load_diag_module(AF_INET, 0); 307 break; 308 case SKNLGRP_INET6_TCP_DESTROY: 309 case SKNLGRP_INET6_UDP_DESTROY: 310 if (!rcu_access_pointer(sock_diag_handlers[AF_INET6])) 311 sock_load_diag_module(AF_INET6, 0); 312 break; 313 } 314 return 0; 315 } 316 317 int sock_diag_destroy(struct sock *sk, int err) 318 { 319 if (!ns_capable(sock_net(sk)->user_ns, CAP_NET_ADMIN)) 320 return -EPERM; 321 322 if (!sk->sk_prot->diag_destroy) 323 return -EOPNOTSUPP; 324 325 return sk->sk_prot->diag_destroy(sk, err); 326 } 327 EXPORT_SYMBOL_GPL(sock_diag_destroy); 328 329 static int __net_init diag_net_init(struct net *net) 330 { 331 struct netlink_kernel_cfg cfg = { 332 .groups = SKNLGRP_MAX, 333 .input = sock_diag_rcv, 334 .bind = sock_diag_bind, 335 .flags = NL_CFG_F_NONROOT_RECV, 336 }; 337 338 net->diag_nlsk = netlink_kernel_create(net, NETLINK_SOCK_DIAG, &cfg); 339 return net->diag_nlsk == NULL ? -ENOMEM : 0; 340 } 341 342 static void __net_exit diag_net_exit(struct net *net) 343 { 344 netlink_kernel_release(net->diag_nlsk); 345 net->diag_nlsk = NULL; 346 } 347 348 static struct pernet_operations diag_net_ops = { 349 .init = diag_net_init, 350 .exit = diag_net_exit, 351 }; 352 353 static int __init sock_diag_init(void) 354 { 355 broadcast_wq = alloc_workqueue("sock_diag_events", 0, 0); 356 BUG_ON(!broadcast_wq); 357 return register_pernet_subsys(&diag_net_ops); 358 } 359 device_initcall(sock_diag_init); 360