root/net/ipv4/raw_diag.c
// SPDX-License-Identifier: GPL-2.0-only
#include <linux/module.h>

#include <linux/inet_diag.h>
#include <linux/sock_diag.h>

#include <net/inet_sock.h>
#include <net/raw.h>
#include <net/rawv6.h>

#ifdef pr_fmt
# undef pr_fmt
#endif

#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

static struct raw_hashinfo *
raw_get_hashinfo(const struct inet_diag_req_v2 *r)
{
        if (r->sdiag_family == AF_INET) {
                return &raw_v4_hashinfo;
#if IS_ENABLED(CONFIG_IPV6)
        } else if (r->sdiag_family == AF_INET6) {
                return &raw_v6_hashinfo;
#endif
        } else {
                return ERR_PTR(-EINVAL);
        }
}

/*
 * Due to requirement of not breaking user API we can't simply
 * rename @pad field in inet_diag_req_v2 structure, instead
 * use helper to figure it out.
 */

static bool raw_lookup(struct net *net, const struct sock *sk,
                       const struct inet_diag_req_v2 *req)
{
        struct inet_diag_req_raw *r = (void *)req;

        if (r->sdiag_family == AF_INET)
                return raw_v4_match(net, sk, r->sdiag_raw_protocol,
                                    r->id.idiag_dst[0],
                                    r->id.idiag_src[0],
                                    r->id.idiag_if, 0);
#if IS_ENABLED(CONFIG_IPV6)
        else
                return raw_v6_match(net, sk, r->sdiag_raw_protocol,
                                    (const struct in6_addr *)r->id.idiag_src,
                                    (const struct in6_addr *)r->id.idiag_dst,
                                    r->id.idiag_if, 0);
#endif
        return false;
}

static struct sock *raw_sock_get(struct net *net, const struct inet_diag_req_v2 *r)
{
        struct raw_hashinfo *hashinfo = raw_get_hashinfo(r);
        struct hlist_head *hlist;
        struct sock *sk;
        int slot;

        if (IS_ERR(hashinfo))
                return ERR_CAST(hashinfo);

        rcu_read_lock();
        for (slot = 0; slot < RAW_HTABLE_SIZE; slot++) {
                hlist = &hashinfo->ht[slot];
                sk_for_each_rcu(sk, hlist) {
                        if (raw_lookup(net, sk, r)) {
                                /*
                                 * Grab it and keep until we fill
                                 * diag message to be reported, so
                                 * caller should call sock_put then.
                                 */
                                if (refcount_inc_not_zero(&sk->sk_refcnt))
                                        goto out_unlock;
                        }
                }
        }
        sk = ERR_PTR(-ENOENT);
out_unlock:
        rcu_read_unlock();

        return sk;
}

static int raw_diag_dump_one(struct netlink_callback *cb,
                             const struct inet_diag_req_v2 *r)
{
        struct sk_buff *in_skb = cb->skb;
        struct sk_buff *rep;
        struct sock *sk;
        struct net *net;
        int err;

        net = sock_net(in_skb->sk);
        sk = raw_sock_get(net, r);
        if (IS_ERR(sk))
                return PTR_ERR(sk);

        rep = nlmsg_new(nla_total_size(sizeof(struct inet_diag_msg)) +
                        inet_diag_msg_attrs_size() +
                        nla_total_size(sizeof(struct inet_diag_meminfo)) + 64,
                        GFP_KERNEL);
        if (!rep) {
                sock_put(sk);
                return -ENOMEM;
        }

        err = inet_sk_diag_fill(sk, NULL, rep, cb, r, 0,
                                netlink_net_capable(in_skb, CAP_NET_ADMIN));
        sock_put(sk);

        if (err < 0) {
                kfree_skb(rep);
                return err;
        }

        err = nlmsg_unicast(net->diag_nlsk, rep, NETLINK_CB(in_skb).portid);

        return err;
}

static int sk_diag_dump(struct sock *sk, struct sk_buff *skb,
                        struct netlink_callback *cb,
                        const struct inet_diag_req_v2 *r,
                        bool net_admin)
{
        if (!inet_diag_bc_sk(cb->data, sk))
                return 0;

        return inet_sk_diag_fill(sk, NULL, skb, cb, r, NLM_F_MULTI, net_admin);
}

static void raw_diag_dump(struct sk_buff *skb, struct netlink_callback *cb,
                          const struct inet_diag_req_v2 *r)
{
        bool net_admin = netlink_net_capable(cb->skb, CAP_NET_ADMIN);
        struct raw_hashinfo *hashinfo = raw_get_hashinfo(r);
        struct net *net = sock_net(skb->sk);
        int num, s_num, slot, s_slot;
        struct hlist_head *hlist;
        struct sock *sk = NULL;

        if (IS_ERR(hashinfo))
                return;

        s_slot = cb->args[0];
        num = s_num = cb->args[1];

        rcu_read_lock();
        for (slot = s_slot; slot < RAW_HTABLE_SIZE; s_num = 0, slot++) {
                num = 0;

                hlist = &hashinfo->ht[slot];
                sk_for_each_rcu(sk, hlist) {
                        struct inet_sock *inet = inet_sk(sk);

                        if (!net_eq(sock_net(sk), net))
                                continue;
                        if (num < s_num)
                                goto next;
                        if (sk->sk_family != r->sdiag_family)
                                goto next;
                        if (r->id.idiag_sport != inet->inet_sport &&
                            r->id.idiag_sport)
                                goto next;
                        if (r->id.idiag_dport != inet->inet_dport &&
                            r->id.idiag_dport)
                                goto next;
                        if (sk_diag_dump(sk, skb, cb, r, net_admin) < 0)
                                goto out_unlock;
next:
                        num++;
                }
        }

out_unlock:
        rcu_read_unlock();

        cb->args[0] = slot;
        cb->args[1] = num;
}

static void raw_diag_get_info(struct sock *sk, struct inet_diag_msg *r,
                              void *info)
{
        r->idiag_rqueue = sk_rmem_alloc_get(sk);
        r->idiag_wqueue = sk_wmem_alloc_get(sk);
}

#ifdef CONFIG_INET_DIAG_DESTROY
static int raw_diag_destroy(struct sk_buff *in_skb,
                            const struct inet_diag_req_v2 *r)
{
        struct net *net = sock_net(in_skb->sk);
        struct sock *sk;
        int err;

        sk = raw_sock_get(net, r);
        if (IS_ERR(sk))
                return PTR_ERR(sk);
        err = sock_diag_destroy(sk, ECONNABORTED);
        sock_put(sk);
        return err;
}
#endif

static const struct inet_diag_handler raw_diag_handler = {
        .owner                  = THIS_MODULE,
        .dump                   = raw_diag_dump,
        .dump_one               = raw_diag_dump_one,
        .idiag_get_info         = raw_diag_get_info,
        .idiag_type             = IPPROTO_RAW,
        .idiag_info_size        = 0,
#ifdef CONFIG_INET_DIAG_DESTROY
        .destroy                = raw_diag_destroy,
#endif
};

static void __always_unused __check_inet_diag_req_raw(void)
{
        /*
         * Make sure the two structures are identical,
         * except the @pad field.
         */
#define __offset_mismatch(m1, m2)                       \
        (offsetof(struct inet_diag_req_v2, m1) !=       \
         offsetof(struct inet_diag_req_raw, m2))

        BUILD_BUG_ON(sizeof(struct inet_diag_req_v2) !=
                     sizeof(struct inet_diag_req_raw));
        BUILD_BUG_ON(__offset_mismatch(sdiag_family, sdiag_family));
        BUILD_BUG_ON(__offset_mismatch(sdiag_protocol, sdiag_protocol));
        BUILD_BUG_ON(__offset_mismatch(idiag_ext, idiag_ext));
        BUILD_BUG_ON(__offset_mismatch(pad, sdiag_raw_protocol));
        BUILD_BUG_ON(__offset_mismatch(idiag_states, idiag_states));
        BUILD_BUG_ON(__offset_mismatch(id, id));
#undef __offset_mismatch
}

static int __init raw_diag_init(void)
{
        return inet_diag_register(&raw_diag_handler);
}

static void __exit raw_diag_exit(void)
{
        inet_diag_unregister(&raw_diag_handler);
}

module_init(raw_diag_init);
module_exit(raw_diag_exit);
MODULE_LICENSE("GPL");
MODULE_DESCRIPTION("RAW socket monitoring via SOCK_DIAG");
MODULE_ALIAS_NET_PF_PROTO_TYPE(PF_NETLINK, NETLINK_SOCK_DIAG, 2-255 /* AF_INET - IPPROTO_RAW */);
MODULE_ALIAS_NET_PF_PROTO_TYPE(PF_NETLINK, NETLINK_SOCK_DIAG, 10-255 /* AF_INET6 - IPPROTO_RAW */);