net/core/sock_diag.c

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