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