linux/net/unix/diag.c
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   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
  14static int sk_diag_dump_name(struct sock *sk, struct sk_buff *nlskb)
  15{
  16        /* might or might not have unix_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, addr->len - sizeof(short),
  23                       addr->name->sun_path);
  24}
  25
  26static int sk_diag_dump_vfs(struct sock *sk, struct sk_buff *nlskb)
  27{
  28        struct dentry *dentry = unix_sk(sk)->path.dentry;
  29
  30        if (dentry) {
  31                struct unix_diag_vfs uv = {
  32                        .udiag_vfs_ino = d_backing_inode(dentry)->i_ino,
  33                        .udiag_vfs_dev = dentry->d_sb->s_dev,
  34                };
  35
  36                return nla_put(nlskb, UNIX_DIAG_VFS, sizeof(uv), &uv);
  37        }
  38
  39        return 0;
  40}
  41
  42static int sk_diag_dump_peer(struct sock *sk, struct sk_buff *nlskb)
  43{
  44        struct sock *peer;
  45        int ino;
  46
  47        peer = unix_peer_get(sk);
  48        if (peer) {
  49                unix_state_lock(peer);
  50                ino = sock_i_ino(peer);
  51                unix_state_unlock(peer);
  52                sock_put(peer);
  53
  54                return nla_put_u32(nlskb, UNIX_DIAG_PEER, ino);
  55        }
  56
  57        return 0;
  58}
  59
  60static int sk_diag_dump_icons(struct sock *sk, struct sk_buff *nlskb)
  61{
  62        struct sk_buff *skb;
  63        struct nlattr *attr;
  64        u32 *buf;
  65        int i;
  66
  67        if (sk->sk_state == TCP_LISTEN) {
  68                spin_lock(&sk->sk_receive_queue.lock);
  69
  70                attr = nla_reserve(nlskb, UNIX_DIAG_ICONS,
  71                                   sk->sk_receive_queue.qlen * sizeof(u32));
  72                if (!attr)
  73                        goto errout;
  74
  75                buf = nla_data(attr);
  76                i = 0;
  77                skb_queue_walk(&sk->sk_receive_queue, skb) {
  78                        struct sock *req, *peer;
  79
  80                        req = skb->sk;
  81                        /*
  82                         * The state lock is outer for the same sk's
  83                         * queue lock. With the other's queue locked it's
  84                         * OK to lock the state.
  85                         */
  86                        unix_state_lock_nested(req);
  87                        peer = unix_sk(req)->peer;
  88                        buf[i++] = (peer ? sock_i_ino(peer) : 0);
  89                        unix_state_unlock(req);
  90                }
  91                spin_unlock(&sk->sk_receive_queue.lock);
  92        }
  93
  94        return 0;
  95
  96errout:
  97        spin_unlock(&sk->sk_receive_queue.lock);
  98        return -EMSGSIZE;
  99}
 100
 101static int sk_diag_show_rqlen(struct sock *sk, struct sk_buff *nlskb)
 102{
 103        struct unix_diag_rqlen rql;
 104
 105        if (sk->sk_state == TCP_LISTEN) {
 106                rql.udiag_rqueue = sk->sk_receive_queue.qlen;
 107                rql.udiag_wqueue = sk->sk_max_ack_backlog;
 108        } else {
 109                rql.udiag_rqueue = (u32) unix_inq_len(sk);
 110                rql.udiag_wqueue = (u32) unix_outq_len(sk);
 111        }
 112
 113        return nla_put(nlskb, UNIX_DIAG_RQLEN, sizeof(rql), &rql);
 114}
 115
 116static int sk_diag_dump_uid(struct sock *sk, struct sk_buff *nlskb)
 117{
 118        uid_t uid = from_kuid_munged(sk_user_ns(nlskb->sk), sock_i_uid(sk));
 119        return nla_put(nlskb, UNIX_DIAG_UID, sizeof(uid_t), &uid);
 120}
 121
 122static int sk_diag_fill(struct sock *sk, struct sk_buff *skb, struct unix_diag_req *req,
 123                u32 portid, u32 seq, u32 flags, int sk_ino)
 124{
 125        struct nlmsghdr *nlh;
 126        struct unix_diag_msg *rep;
 127
 128        nlh = nlmsg_put(skb, portid, seq, SOCK_DIAG_BY_FAMILY, sizeof(*rep),
 129                        flags);
 130        if (!nlh)
 131                return -EMSGSIZE;
 132
 133        rep = nlmsg_data(nlh);
 134        rep->udiag_family = AF_UNIX;
 135        rep->udiag_type = sk->sk_type;
 136        rep->udiag_state = sk->sk_state;
 137        rep->pad = 0;
 138        rep->udiag_ino = sk_ino;
 139        sock_diag_save_cookie(sk, rep->udiag_cookie);
 140
 141        if ((req->udiag_show & UDIAG_SHOW_NAME) &&
 142            sk_diag_dump_name(sk, skb))
 143                goto out_nlmsg_trim;
 144
 145        if ((req->udiag_show & UDIAG_SHOW_VFS) &&
 146            sk_diag_dump_vfs(sk, skb))
 147                goto out_nlmsg_trim;
 148
 149        if ((req->udiag_show & UDIAG_SHOW_PEER) &&
 150            sk_diag_dump_peer(sk, skb))
 151                goto out_nlmsg_trim;
 152
 153        if ((req->udiag_show & UDIAG_SHOW_ICONS) &&
 154            sk_diag_dump_icons(sk, skb))
 155                goto out_nlmsg_trim;
 156
 157        if ((req->udiag_show & UDIAG_SHOW_RQLEN) &&
 158            sk_diag_show_rqlen(sk, skb))
 159                goto out_nlmsg_trim;
 160
 161        if ((req->udiag_show & UDIAG_SHOW_MEMINFO) &&
 162            sock_diag_put_meminfo(sk, skb, UNIX_DIAG_MEMINFO))
 163                goto out_nlmsg_trim;
 164
 165        if (nla_put_u8(skb, UNIX_DIAG_SHUTDOWN, sk->sk_shutdown))
 166                goto out_nlmsg_trim;
 167
 168        if ((req->udiag_show & UDIAG_SHOW_UID) &&
 169            sk_diag_dump_uid(sk, skb))
 170                goto out_nlmsg_trim;
 171
 172        nlmsg_end(skb, nlh);
 173        return 0;
 174
 175out_nlmsg_trim:
 176        nlmsg_cancel(skb, nlh);
 177        return -EMSGSIZE;
 178}
 179
 180static int sk_diag_dump(struct sock *sk, struct sk_buff *skb, struct unix_diag_req *req,
 181                u32 portid, u32 seq, u32 flags)
 182{
 183        int sk_ino;
 184
 185        unix_state_lock(sk);
 186        sk_ino = sock_i_ino(sk);
 187        unix_state_unlock(sk);
 188
 189        if (!sk_ino)
 190                return 0;
 191
 192        return sk_diag_fill(sk, skb, req, portid, seq, flags, sk_ino);
 193}
 194
 195static int unix_diag_dump(struct sk_buff *skb, struct netlink_callback *cb)
 196{
 197        struct unix_diag_req *req;
 198        int num, s_num, slot, s_slot;
 199        struct net *net = sock_net(skb->sk);
 200
 201        req = nlmsg_data(cb->nlh);
 202
 203        s_slot = cb->args[0];
 204        num = s_num = cb->args[1];
 205
 206        spin_lock(&unix_table_lock);
 207        for (slot = s_slot;
 208             slot < ARRAY_SIZE(unix_socket_table);
 209             s_num = 0, slot++) {
 210                struct sock *sk;
 211
 212                num = 0;
 213                sk_for_each(sk, &unix_socket_table[slot]) {
 214                        if (!net_eq(sock_net(sk), net))
 215                                continue;
 216                        if (num < s_num)
 217                                goto next;
 218                        if (!(req->udiag_states & (1 << sk->sk_state)))
 219                                goto next;
 220                        if (sk_diag_dump(sk, skb, req,
 221                                         NETLINK_CB(cb->skb).portid,
 222                                         cb->nlh->nlmsg_seq,
 223                                         NLM_F_MULTI) < 0)
 224                                goto done;
 225next:
 226                        num++;
 227                }
 228        }
 229done:
 230        spin_unlock(&unix_table_lock);
 231        cb->args[0] = slot;
 232        cb->args[1] = num;
 233
 234        return skb->len;
 235}
 236
 237static struct sock *unix_lookup_by_ino(unsigned int ino)
 238{
 239        int i;
 240        struct sock *sk;
 241
 242        spin_lock(&unix_table_lock);
 243        for (i = 0; i < ARRAY_SIZE(unix_socket_table); i++) {
 244                sk_for_each(sk, &unix_socket_table[i])
 245                        if (ino == sock_i_ino(sk)) {
 246                                sock_hold(sk);
 247                                spin_unlock(&unix_table_lock);
 248
 249                                return sk;
 250                        }
 251        }
 252
 253        spin_unlock(&unix_table_lock);
 254        return NULL;
 255}
 256
 257static int unix_diag_get_exact(struct sk_buff *in_skb,
 258                               const struct nlmsghdr *nlh,
 259                               struct unix_diag_req *req)
 260{
 261        int err = -EINVAL;
 262        struct sock *sk;
 263        struct sk_buff *rep;
 264        unsigned int extra_len;
 265        struct net *net = sock_net(in_skb->sk);
 266
 267        if (req->udiag_ino == 0)
 268                goto out_nosk;
 269
 270        sk = unix_lookup_by_ino(req->udiag_ino);
 271        err = -ENOENT;
 272        if (sk == NULL)
 273                goto out_nosk;
 274        if (!net_eq(sock_net(sk), net))
 275                goto out;
 276
 277        err = sock_diag_check_cookie(sk, req->udiag_cookie);
 278        if (err)
 279                goto out;
 280
 281        extra_len = 256;
 282again:
 283        err = -ENOMEM;
 284        rep = nlmsg_new(sizeof(struct unix_diag_msg) + extra_len, GFP_KERNEL);
 285        if (!rep)
 286                goto out;
 287
 288        err = sk_diag_fill(sk, rep, req, NETLINK_CB(in_skb).portid,
 289                           nlh->nlmsg_seq, 0, req->udiag_ino);
 290        if (err < 0) {
 291                nlmsg_free(rep);
 292                extra_len += 256;
 293                if (extra_len >= PAGE_SIZE)
 294                        goto out;
 295
 296                goto again;
 297        }
 298        err = nlmsg_unicast(net->diag_nlsk, rep, NETLINK_CB(in_skb).portid);
 299
 300out:
 301        if (sk)
 302                sock_put(sk);
 303out_nosk:
 304        return err;
 305}
 306
 307static int unix_diag_handler_dump(struct sk_buff *skb, struct nlmsghdr *h)
 308{
 309        int hdrlen = sizeof(struct unix_diag_req);
 310        struct net *net = sock_net(skb->sk);
 311
 312        if (nlmsg_len(h) < hdrlen)
 313                return -EINVAL;
 314
 315        if (h->nlmsg_flags & NLM_F_DUMP) {
 316                struct netlink_dump_control c = {
 317                        .dump = unix_diag_dump,
 318                };
 319                return netlink_dump_start(net->diag_nlsk, skb, h, &c);
 320        } else
 321                return unix_diag_get_exact(skb, h, nlmsg_data(h));
 322}
 323
 324static const struct sock_diag_handler unix_diag_handler = {
 325        .family = AF_UNIX,
 326        .dump = unix_diag_handler_dump,
 327};
 328
 329static int __init unix_diag_init(void)
 330{
 331        return sock_diag_register(&unix_diag_handler);
 332}
 333
 334static void __exit unix_diag_exit(void)
 335{
 336        sock_diag_unregister(&unix_diag_handler);
 337}
 338
 339module_init(unix_diag_init);
 340module_exit(unix_diag_exit);
 341MODULE_LICENSE("GPL");
 342MODULE_ALIAS_NET_PF_PROTO_TYPE(PF_NETLINK, NETLINK_SOCK_DIAG, 1 /* AF_LOCAL */);
 343