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
  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);