1 /* License: GPL */ 2 3 #include <linux/mutex.h> 4 #include <linux/socket.h> 5 #include <linux/skbuff.h> 6 #include <net/netlink.h> 7 #include <net/net_namespace.h> 8 #include <linux/module.h> 9 #include <net/sock.h> 10 #include <linux/kernel.h> 11 #include <linux/tcp.h> 12 #include <linux/workqueue.h> 13 #include <linux/nospec.h> 14 15 #include <linux/inet_diag.h> 16 #include <linux/sock_diag.h> 17 18 static const struct sock_diag_handler *sock_diag_handlers[AF_MAX]; 19 static int (*inet_rcv_compat)(struct sk_buff *skb, struct nlmsghdr *nlh); 20 static DEFINE_MUTEX(sock_diag_table_mutex); 21 static struct workqueue_struct *broadcast_wq; 22 static atomic64_t cookie_gen; 23 24 u64 sock_gen_cookie(struct sock *sk) 25 { 26 while (1) { 27 u64 res = atomic64_read(&sk->sk_cookie); 28 29 if (res) 30 return res; 31 res = atomic64_inc_return(&cookie_gen); 32 atomic64_cmpxchg(&sk->sk_cookie, 0, res); 33 } 34 } 35 36 int sock_diag_check_cookie(struct sock *sk, const __u32 *cookie) 37 { 38 u64 res; 39 40 if (cookie[0] == INET_DIAG_NOCOOKIE && cookie[1] == INET_DIAG_NOCOOKIE) 41 return 0; 42 43 res = sock_gen_cookie(sk); 44 if ((u32)res != cookie[0] || (u32)(res >> 32) != cookie[1]) 45 return -ESTALE; 46 47 return 0; 48 } 49 EXPORT_SYMBOL_GPL(sock_diag_check_cookie); 50 51 void sock_diag_save_cookie(struct sock *sk, __u32 *cookie) 52 { 53 u64 res = sock_gen_cookie(sk); 54 55 cookie[0] = (u32)res; 56 cookie[1] = (u32)(res >> 32); 57 } 58 EXPORT_SYMBOL_GPL(sock_diag_save_cookie); 59 60 int sock_diag_put_meminfo(struct sock *sk, struct sk_buff *skb, int attrtype) 61 { 62 u32 mem[SK_MEMINFO_VARS]; 63 64 sk_get_meminfo(sk, mem); 65 66 return nla_put(skb, attrtype, sizeof(mem), &mem); 67 } 68 EXPORT_SYMBOL_GPL(sock_diag_put_meminfo); 69 70 int sock_diag_put_filterinfo(bool may_report_filterinfo, struct sock *sk, 71 struct sk_buff *skb, int attrtype) 72 { 73 struct sock_fprog_kern *fprog; 74 struct sk_filter *filter; 75 struct nlattr *attr; 76 unsigned int flen; 77 int err = 0; 78 79 if (!may_report_filterinfo) { 80 nla_reserve(skb, attrtype, 0); 81 return 0; 82 } 83 84 rcu_read_lock(); 85 filter = rcu_dereference(sk->sk_filter); 86 if (!filter) 87 goto out; 88 89 fprog = filter->prog->orig_prog; 90 if (!fprog) 91 goto out; 92 93 flen = bpf_classic_proglen(fprog); 94 95 attr = nla_reserve(skb, attrtype, flen); 96 if (attr == NULL) { 97 err = -EMSGSIZE; 98 goto out; 99 } 100 101 memcpy(nla_data(attr), fprog->filter, flen); 102 out: 103 rcu_read_unlock(); 104 return err; 105 } 106 EXPORT_SYMBOL(sock_diag_put_filterinfo); 107 108 struct broadcast_sk { 109 struct sock *sk; 110 struct work_struct work; 111 }; 112 113 static size_t sock_diag_nlmsg_size(void) 114 { 115 return NLMSG_ALIGN(sizeof(struct inet_diag_msg) 116 + nla_total_size(sizeof(u8)) /* INET_DIAG_PROTOCOL */ 117 + nla_total_size_64bit(sizeof(struct tcp_info))); /* INET_DIAG_INFO */ 118 } 119 120 static void sock_diag_broadcast_destroy_work(struct work_struct *work) 121 { 122 struct broadcast_sk *bsk = 123 container_of(work, struct broadcast_sk, work); 124 struct sock *sk = bsk->sk; 125 const struct sock_diag_handler *hndl; 126 struct sk_buff *skb; 127 const enum sknetlink_groups group = sock_diag_destroy_group(sk); 128 int err = -1; 129 130 WARN_ON(group == SKNLGRP_NONE); 131 132 skb = nlmsg_new(sock_diag_nlmsg_size(), GFP_KERNEL); 133 if (!skb) 134 goto out; 135 136 mutex_lock(&sock_diag_table_mutex); 137 hndl = sock_diag_handlers[sk->sk_family]; 138 if (hndl && hndl->get_info) 139 err = hndl->get_info(skb, sk); 140 mutex_unlock(&sock_diag_table_mutex); 141 142 if (!err) 143 nlmsg_multicast(sock_net(sk)->diag_nlsk, skb, 0, group, 144 GFP_KERNEL); 145 else 146 kfree_skb(skb); 147 out: 148 sk_destruct(sk); 149 kfree(bsk); 150 } 151 152 void sock_diag_broadcast_destroy(struct sock *sk) 153 { 154 /* Note, this function is often called from an interrupt context. */ 155 struct broadcast_sk *bsk = 156 kmalloc(sizeof(struct broadcast_sk), GFP_ATOMIC); 157 if (!bsk) 158 return sk_destruct(sk); 159 bsk->sk = sk; 160 INIT_WORK(&bsk->work, sock_diag_broadcast_destroy_work); 161 queue_work(broadcast_wq, &bsk->work); 162 } 163 164 void sock_diag_register_inet_compat(int (*fn)(struct sk_buff *skb, struct nlmsghdr *nlh)) 165 { 166 mutex_lock(&sock_diag_table_mutex); 167 inet_rcv_compat = fn; 168 mutex_unlock(&sock_diag_table_mutex); 169 } 170 EXPORT_SYMBOL_GPL(sock_diag_register_inet_compat); 171 172 void sock_diag_unregister_inet_compat(int (*fn)(struct sk_buff *skb, struct nlmsghdr *nlh)) 173 { 174 mutex_lock(&sock_diag_table_mutex); 175 inet_rcv_compat = NULL; 176 mutex_unlock(&sock_diag_table_mutex); 177 } 178 EXPORT_SYMBOL_GPL(sock_diag_unregister_inet_compat); 179 180 int sock_diag_register(const struct sock_diag_handler *hndl) 181 { 182 int err = 0; 183 184 if (hndl->family >= AF_MAX) 185 return -EINVAL; 186 187 mutex_lock(&sock_diag_table_mutex); 188 if (sock_diag_handlers[hndl->family]) 189 err = -EBUSY; 190 else 191 sock_diag_handlers[hndl->family] = hndl; 192 mutex_unlock(&sock_diag_table_mutex); 193 194 return err; 195 } 196 EXPORT_SYMBOL_GPL(sock_diag_register); 197 198 void sock_diag_unregister(const struct sock_diag_handler *hnld) 199 { 200 int family = hnld->family; 201 202 if (family >= AF_MAX) 203 return; 204 205 mutex_lock(&sock_diag_table_mutex); 206 BUG_ON(sock_diag_handlers[family] != hnld); 207 sock_diag_handlers[family] = NULL; 208 mutex_unlock(&sock_diag_table_mutex); 209 } 210 EXPORT_SYMBOL_GPL(sock_diag_unregister); 211 212 static int __sock_diag_cmd(struct sk_buff *skb, struct nlmsghdr *nlh) 213 { 214 int err; 215 struct sock_diag_req *req = nlmsg_data(nlh); 216 const struct sock_diag_handler *hndl; 217 218 if (nlmsg_len(nlh) < sizeof(*req)) 219 return -EINVAL; 220 221 if (req->sdiag_family >= AF_MAX) 222 return -EINVAL; 223 req->sdiag_family = array_index_nospec(req->sdiag_family, AF_MAX); 224 225 if (sock_diag_handlers[req->sdiag_family] == NULL) 226 sock_load_diag_module(req->sdiag_family, 0); 227 228 mutex_lock(&sock_diag_table_mutex); 229 hndl = sock_diag_handlers[req->sdiag_family]; 230 if (hndl == NULL) 231 err = -ENOENT; 232 else if (nlh->nlmsg_type == SOCK_DIAG_BY_FAMILY) 233 err = hndl->dump(skb, nlh); 234 else if (nlh->nlmsg_type == SOCK_DESTROY && hndl->destroy) 235 err = hndl->destroy(skb, nlh); 236 else 237 err = -EOPNOTSUPP; 238 mutex_unlock(&sock_diag_table_mutex); 239 240 return err; 241 } 242 243 static int sock_diag_rcv_msg(struct sk_buff *skb, struct nlmsghdr *nlh, 244 struct netlink_ext_ack *extack) 245 { 246 int ret; 247 248 switch (nlh->nlmsg_type) { 249 case TCPDIAG_GETSOCK: 250 case DCCPDIAG_GETSOCK: 251 if (inet_rcv_compat == NULL) 252 sock_load_diag_module(AF_INET, 0); 253 254 mutex_lock(&sock_diag_table_mutex); 255 if (inet_rcv_compat != NULL) 256 ret = inet_rcv_compat(skb, nlh); 257 else 258 ret = -EOPNOTSUPP; 259 mutex_unlock(&sock_diag_table_mutex); 260 261 return ret; 262 case SOCK_DIAG_BY_FAMILY: 263 case SOCK_DESTROY: 264 return __sock_diag_cmd(skb, nlh); 265 default: 266 return -EINVAL; 267 } 268 } 269 270 static DEFINE_MUTEX(sock_diag_mutex); 271 272 static void sock_diag_rcv(struct sk_buff *skb) 273 { 274 mutex_lock(&sock_diag_mutex); 275 netlink_rcv_skb(skb, &sock_diag_rcv_msg); 276 mutex_unlock(&sock_diag_mutex); 277 } 278 279 static int sock_diag_bind(struct net *net, int group) 280 { 281 switch (group) { 282 case SKNLGRP_INET_TCP_DESTROY: 283 case SKNLGRP_INET_UDP_DESTROY: 284 if (!sock_diag_handlers[AF_INET]) 285 sock_load_diag_module(AF_INET, 0); 286 break; 287 case SKNLGRP_INET6_TCP_DESTROY: 288 case SKNLGRP_INET6_UDP_DESTROY: 289 if (!sock_diag_handlers[AF_INET6]) 290 sock_load_diag_module(AF_INET6, 0); 291 break; 292 } 293 return 0; 294 } 295 296 int sock_diag_destroy(struct sock *sk, int err) 297 { 298 if (!ns_capable(sock_net(sk)->user_ns, CAP_NET_ADMIN)) 299 return -EPERM; 300 301 if (!sk->sk_prot->diag_destroy) 302 return -EOPNOTSUPP; 303 304 return sk->sk_prot->diag_destroy(sk, err); 305 } 306 EXPORT_SYMBOL_GPL(sock_diag_destroy); 307 308 static int __net_init diag_net_init(struct net *net) 309 { 310 struct netlink_kernel_cfg cfg = { 311 .groups = SKNLGRP_MAX, 312 .input = sock_diag_rcv, 313 .bind = sock_diag_bind, 314 .flags = NL_CFG_F_NONROOT_RECV, 315 }; 316 317 net->diag_nlsk = netlink_kernel_create(net, NETLINK_SOCK_DIAG, &cfg); 318 return net->diag_nlsk == NULL ? -ENOMEM : 0; 319 } 320 321 static void __net_exit diag_net_exit(struct net *net) 322 { 323 netlink_kernel_release(net->diag_nlsk); 324 net->diag_nlsk = NULL; 325 } 326 327 static struct pernet_operations diag_net_ops = { 328 .init = diag_net_init, 329 .exit = diag_net_exit, 330 }; 331 332 static int __init sock_diag_init(void) 333 { 334 broadcast_wq = alloc_workqueue("sock_diag_events", 0, 0); 335 BUG_ON(!broadcast_wq); 336 return register_pernet_subsys(&diag_net_ops); 337 } 338 device_initcall(sock_diag_init); 339