net/unix/diag.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 #include <linux/types.h>
   3 #include <linux/spinlock.h>
   4 #include <linux/sock_diag.h>
   5 #include <linux/unix_diag.h>
   6 #include <linux/skbuff.h>
   7 #include <linux/module.h>
   8 #include <linux/uidgid.h>
   9 #include <net/netlink.h>
  10 #include <net/af_unix.h>
  11 #include <net/tcp_states.h>
  12 #include <net/sock.h>
  13
  14 static int sk_diag_dump_name(struct sock *sk, struct sk_buff *nlskb)
  15 {
  16         /* might or might not have a hash table lock */
  17         struct unix_address *addr = smp_load_acquire(&unix_sk(sk)->addr);
  18
  19         if (!addr)
  20                 return 0;
  21
  22         return nla_put(nlskb, UNIX_DIAG_NAME,
  23                        addr->len - offsetof(struct sockaddr_un, sun_path),
  24                        addr->name->sun_path);
  25 }
  26
  27 static int sk_diag_dump_vfs(struct sock *sk, struct sk_buff *nlskb)
  28 {
  29         struct dentry *dentry = unix_sk(sk)->path.dentry;
  30
  31         if (dentry) {
  32                 struct unix_diag_vfs uv = {
  33                         .udiag_vfs_ino = d_backing_inode(dentry)->i_ino,
  34                         .udiag_vfs_dev = dentry->d_sb->s_dev,
  35                 };
  36
  37                 return nla_put(nlskb, UNIX_DIAG_VFS, sizeof(uv), &uv);
  38         }
  39
  40         return 0;
  41 }
  42
  43 static int sk_diag_dump_peer(struct sock *sk, struct sk_buff *nlskb)
  44 {
  45         struct sock *peer;
  46         int ino;
  47
  48         peer = unix_peer_get(sk);
  49         if (peer) {
  50                 ino = sock_i_ino(peer);
  51                 sock_put(peer);
  52
  53                 return nla_put_u32(nlskb, UNIX_DIAG_PEER, ino);
  54         }
  55
  56         return 0;
  57 }
  58
  59 static int sk_diag_dump_icons(struct sock *sk, struct sk_buff *nlskb)
  60 {
  61         struct sk_buff *skb;
  62         struct nlattr *attr;
  63         u32 *buf;
  64         int i;
  65
  66         if (READ_ONCE(sk->sk_state) == TCP_LISTEN) {
  67                 spin_lock(&sk->sk_receive_queue.lock);
  68
  69                 attr = nla_reserve(nlskb, UNIX_DIAG_ICONS,
  70                                    sk->sk_receive_queue.qlen * sizeof(u32));
  71                 if (!attr)
  72                         goto errout;
  73
  74                 buf = nla_data(attr);
  75                 i = 0;
  76                 skb_queue_walk(&sk->sk_receive_queue, skb)
  77                         buf[i++] = sock_i_ino(unix_peer(skb->sk));
  78
  79                 spin_unlock(&sk->sk_receive_queue.lock);
  80         }
  81
  82         return 0;
  83
  84 errout:
  85         spin_unlock(&sk->sk_receive_queue.lock);
  86         return -EMSGSIZE;
  87 }
  88
  89 static int sk_diag_show_rqlen(struct sock *sk, struct sk_buff *nlskb)
  90 {
  91         struct unix_diag_rqlen rql;
  92
  93         if (READ_ONCE(sk->sk_state) == TCP_LISTEN) {
  94                 rql.udiag_rqueue = skb_queue_len_lockless(&sk->sk_receive_queue);
  95                 rql.udiag_wqueue = sk->sk_max_ack_backlog;
  96         } else {
  97                 rql.udiag_rqueue = (u32) unix_inq_len(sk);
  98                 rql.udiag_wqueue = (u32) unix_outq_len(sk);
  99         }
 100
 101         return nla_put(nlskb, UNIX_DIAG_RQLEN, sizeof(rql), &rql);
 102 }
 103
 104 static int sk_diag_dump_uid(struct sock *sk, struct sk_buff *nlskb,
 105                             struct user_namespace *user_ns)
 106 {
 107         uid_t uid = from_kuid_munged(user_ns, sock_i_uid(sk));
 108         return nla_put(nlskb, UNIX_DIAG_UID, sizeof(uid_t), &uid);
 109 }
 110
 111 static int sk_diag_fill(struct sock *sk, struct sk_buff *skb, struct unix_diag_req *req,
 112                         struct user_namespace *user_ns,
 113                         u32 portid, u32 seq, u32 flags, int sk_ino)
 114 {
 115         struct nlmsghdr *nlh;
 116         struct unix_diag_msg *rep;
 117
 118         nlh = nlmsg_put(skb, portid, seq, SOCK_DIAG_BY_FAMILY, sizeof(*rep),
 119                         flags);
 120         if (!nlh)
 121                 return -EMSGSIZE;
 122
 123         rep = nlmsg_data(nlh);
 124         rep->udiag_family = AF_UNIX;
 125         rep->udiag_type = sk->sk_type;
 126         rep->udiag_state = READ_ONCE(sk->sk_state);
 127         rep->pad = 0;
 128         rep->udiag_ino = sk_ino;
 129         sock_diag_save_cookie(sk, rep->udiag_cookie);
 130
 131         if ((req->udiag_show & UDIAG_SHOW_NAME) &&
 132             sk_diag_dump_name(sk, skb))
 133                 goto out_nlmsg_trim;
 134
 135         if ((req->udiag_show & UDIAG_SHOW_VFS) &&
 136             sk_diag_dump_vfs(sk, skb))
 137                 goto out_nlmsg_trim;
 138
 139         if ((req->udiag_show & UDIAG_SHOW_PEER) &&
 140             sk_diag_dump_peer(sk, skb))
 141                 goto out_nlmsg_trim;
 142
 143         if ((req->udiag_show & UDIAG_SHOW_ICONS) &&
 144             sk_diag_dump_icons(sk, skb))
 145                 goto out_nlmsg_trim;
 146
 147         if ((req->udiag_show & UDIAG_SHOW_RQLEN) &&
 148             sk_diag_show_rqlen(sk, skb))
 149                 goto out_nlmsg_trim;
 150
 151         if ((req->udiag_show & UDIAG_SHOW_MEMINFO) &&
 152             sock_diag_put_meminfo(sk, skb, UNIX_DIAG_MEMINFO))
 153                 goto out_nlmsg_trim;
 154
 155         if (nla_put_u8(skb, UNIX_DIAG_SHUTDOWN, READ_ONCE(sk->sk_shutdown)))
 156                 goto out_nlmsg_trim;
 157
 158         if ((req->udiag_show & UDIAG_SHOW_UID) &&
 159             sk_diag_dump_uid(sk, skb, user_ns))
 160                 goto out_nlmsg_trim;
 161
 162         nlmsg_end(skb, nlh);
 163         return 0;
 164
 165 out_nlmsg_trim:
 166         nlmsg_cancel(skb, nlh);
 167         return -EMSGSIZE;
 168 }
 169
 170 static int unix_diag_dump(struct sk_buff *skb, struct netlink_callback *cb)
 171 {
 172         struct net *net = sock_net(skb->sk);
 173         int num, s_num, slot, s_slot;
 174         struct unix_diag_req *req;
 175
 176         req = nlmsg_data(cb->nlh);
 177
 178         s_slot = cb->args[0];
 179         num = s_num = cb->args[1];
 180
 181         for (slot = s_slot; slot < UNIX_HASH_SIZE; s_num = 0, slot++) {
 182                 struct sock *sk;
 183
 184                 num = 0;
 185                 spin_lock(&net->unx.table.locks[slot]);
 186                 sk_for_each(sk, &net->unx.table.buckets[slot]) {
 187                         int sk_ino;
 188
 189                         if (num < s_num)
 190                                 goto next;
 191
 192                         if (!(req->udiag_states & (1 << READ_ONCE(sk->sk_state))))
 193                                 goto next;
 194
 195                         sk_ino = sock_i_ino(sk);
 196                         if (!sk_ino)
 197                                 goto next;
 198
 199                         if (sk_diag_fill(sk, skb, req, sk_user_ns(skb->sk),
 200                                          NETLINK_CB(cb->skb).portid,
 201                                          cb->nlh->nlmsg_seq,
 202                                          NLM_F_MULTI, sk_ino) < 0) {
 203                                 spin_unlock(&net->unx.table.locks[slot]);
 204                                 goto done;
 205                         }
 206 next:
 207                         num++;
 208                 }
 209                 spin_unlock(&net->unx.table.locks[slot]);
 210         }
 211 done:
 212         cb->args[0] = slot;
 213         cb->args[1] = num;
 214
 215         return skb->len;
 216 }
 217
 218 static struct sock *unix_lookup_by_ino(struct net *net, unsigned int ino)
 219 {
 220         struct sock *sk;
 221         int i;
 222
 223         for (i = 0; i < UNIX_HASH_SIZE; i++) {
 224                 spin_lock(&net->unx.table.locks[i]);
 225                 sk_for_each(sk, &net->unx.table.buckets[i]) {
 226                         if (ino == sock_i_ino(sk)) {
 227                                 sock_hold(sk);
 228                                 spin_unlock(&net->unx.table.locks[i]);
 229                                 return sk;
 230                         }
 231                 }
 232                 spin_unlock(&net->unx.table.locks[i]);
 233         }
 234         return NULL;
 235 }
 236
 237 static int unix_diag_get_exact(struct sk_buff *in_skb,
 238                                const struct nlmsghdr *nlh,
 239                                struct unix_diag_req *req)
 240 {
 241         struct net *net = sock_net(in_skb->sk);
 242         unsigned int extra_len;
 243         struct sk_buff *rep;
 244         struct sock *sk;
 245         int err;
 246
 247         err = -EINVAL;
 248         if (req->udiag_ino == 0)
 249                 goto out_nosk;
 250
 251         sk = unix_lookup_by_ino(net, req->udiag_ino);
 252         err = -ENOENT;
 253         if (sk == NULL)
 254                 goto out_nosk;
 255
 256         err = sock_diag_check_cookie(sk, req->udiag_cookie);
 257         if (err)
 258                 goto out;
 259
 260         extra_len = 256;
 261 again:
 262         err = -ENOMEM;
 263         rep = nlmsg_new(sizeof(struct unix_diag_msg) + extra_len, GFP_KERNEL);
 264         if (!rep)
 265                 goto out;
 266
 267         err = sk_diag_fill(sk, rep, req, sk_user_ns(NETLINK_CB(in_skb).sk),
 268                            NETLINK_CB(in_skb).portid,
 269                            nlh->nlmsg_seq, 0, req->udiag_ino);
 270         if (err < 0) {
 271                 nlmsg_free(rep);
 272                 extra_len += 256;
 273                 if (extra_len >= PAGE_SIZE)
 274                         goto out;
 275
 276                 goto again;
 277         }
 278         err = nlmsg_unicast(net->diag_nlsk, rep, NETLINK_CB(in_skb).portid);
 279
 280 out:
 281         if (sk)
 282                 sock_put(sk);
 283 out_nosk:
 284         return err;
 285 }
 286
 287 static int unix_diag_handler_dump(struct sk_buff *skb, struct nlmsghdr *h)
 288 {
 289         int hdrlen = sizeof(struct unix_diag_req);
 290
 291         if (nlmsg_len(h) < hdrlen)
 292                 return -EINVAL;
 293
 294         if (h->nlmsg_flags & NLM_F_DUMP) {
 295                 struct netlink_dump_control c = {
 296                         .dump = unix_diag_dump,
 297                 };
 298                 return netlink_dump_start(sock_net(skb->sk)->diag_nlsk, skb, h, &c);
 299         } else
 300                 return unix_diag_get_exact(skb, h, nlmsg_data(h));
 301 }
 302
 303 static const struct sock_diag_handler unix_diag_handler = {
 304         .owner = THIS_MODULE,
 305         .family = AF_UNIX,
 306         .dump = unix_diag_handler_dump,
 307 };
 308
 309 static int __init unix_diag_init(void)
 310 {
 311         return sock_diag_register(&unix_diag_handler);
 312 }
 313
 314 static void __exit unix_diag_exit(void)
 315 {
 316         sock_diag_unregister(&unix_diag_handler);
 317 }
 318
 319 module_init(unix_diag_init);
 320 module_exit(unix_diag_exit);
 321 MODULE_LICENSE("GPL");
 322 MODULE_DESCRIPTION("UNIX socket monitoring via SOCK_DIAG");
 323 MODULE_ALIAS_NET_PF_PROTO_TYPE(PF_NETLINK, NETLINK_SOCK_DIAG, 1 /* AF_LOCAL */);