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