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