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b4cb4a1391
Toke mentioned unrcu_pointer() existence, allowing to remove some of the ugly casts we have when using xchg() for rcu protected pointers. Also make inet_rcv_compat const. Signed-off-by: Eric Dumazet <edumazet@google.com> Cc: Toke Høiland-Jørgensen <toke@redhat.com> Reviewed-by: Toke Høiland-Jørgensen <toke@redhat.com> Link: https://lore.kernel.org/r/20240604111603.45871-1-edumazet@google.com Signed-off-by: Paolo Abeni <pabeni@redhat.com>
358 lines
8.0 KiB
C
358 lines
8.0 KiB
C
/* License: GPL */
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#include <linux/filter.h>
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#include <linux/mutex.h>
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#include <linux/socket.h>
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#include <linux/skbuff.h>
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#include <net/netlink.h>
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#include <net/net_namespace.h>
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#include <linux/module.h>
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#include <net/sock.h>
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#include <linux/kernel.h>
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#include <linux/tcp.h>
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#include <linux/workqueue.h>
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#include <linux/nospec.h>
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#include <linux/cookie.h>
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#include <linux/inet_diag.h>
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#include <linux/sock_diag.h>
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static const struct sock_diag_handler __rcu *sock_diag_handlers[AF_MAX];
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static const struct sock_diag_inet_compat __rcu *inet_rcv_compat;
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static struct workqueue_struct *broadcast_wq;
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DEFINE_COOKIE(sock_cookie);
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u64 __sock_gen_cookie(struct sock *sk)
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{
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u64 res = atomic64_read(&sk->sk_cookie);
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if (!res) {
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u64 new = gen_cookie_next(&sock_cookie);
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atomic64_cmpxchg(&sk->sk_cookie, res, new);
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/* Another thread might have changed sk_cookie before us. */
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res = atomic64_read(&sk->sk_cookie);
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}
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return res;
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}
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int sock_diag_check_cookie(struct sock *sk, const __u32 *cookie)
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{
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u64 res;
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if (cookie[0] == INET_DIAG_NOCOOKIE && cookie[1] == INET_DIAG_NOCOOKIE)
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return 0;
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res = sock_gen_cookie(sk);
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if ((u32)res != cookie[0] || (u32)(res >> 32) != cookie[1])
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return -ESTALE;
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return 0;
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}
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EXPORT_SYMBOL_GPL(sock_diag_check_cookie);
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void sock_diag_save_cookie(struct sock *sk, __u32 *cookie)
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{
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u64 res = sock_gen_cookie(sk);
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cookie[0] = (u32)res;
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cookie[1] = (u32)(res >> 32);
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}
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EXPORT_SYMBOL_GPL(sock_diag_save_cookie);
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int sock_diag_put_meminfo(struct sock *sk, struct sk_buff *skb, int attrtype)
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{
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u32 mem[SK_MEMINFO_VARS];
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sk_get_meminfo(sk, mem);
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return nla_put(skb, attrtype, sizeof(mem), &mem);
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}
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EXPORT_SYMBOL_GPL(sock_diag_put_meminfo);
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int sock_diag_put_filterinfo(bool may_report_filterinfo, struct sock *sk,
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struct sk_buff *skb, int attrtype)
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{
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struct sock_fprog_kern *fprog;
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struct sk_filter *filter;
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struct nlattr *attr;
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unsigned int flen;
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int err = 0;
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if (!may_report_filterinfo) {
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nla_reserve(skb, attrtype, 0);
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return 0;
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}
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rcu_read_lock();
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filter = rcu_dereference(sk->sk_filter);
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if (!filter)
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goto out;
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fprog = filter->prog->orig_prog;
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if (!fprog)
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goto out;
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flen = bpf_classic_proglen(fprog);
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attr = nla_reserve(skb, attrtype, flen);
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if (attr == NULL) {
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err = -EMSGSIZE;
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goto out;
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}
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memcpy(nla_data(attr), fprog->filter, flen);
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out:
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rcu_read_unlock();
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return err;
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}
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EXPORT_SYMBOL(sock_diag_put_filterinfo);
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struct broadcast_sk {
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struct sock *sk;
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struct work_struct work;
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};
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static size_t sock_diag_nlmsg_size(void)
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{
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return NLMSG_ALIGN(sizeof(struct inet_diag_msg)
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+ nla_total_size(sizeof(u8)) /* INET_DIAG_PROTOCOL */
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+ nla_total_size_64bit(sizeof(struct tcp_info))); /* INET_DIAG_INFO */
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}
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static const struct sock_diag_handler *sock_diag_lock_handler(int family)
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{
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const struct sock_diag_handler *handler;
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rcu_read_lock();
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handler = rcu_dereference(sock_diag_handlers[family]);
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if (handler && !try_module_get(handler->owner))
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handler = NULL;
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rcu_read_unlock();
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return handler;
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}
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static void sock_diag_unlock_handler(const struct sock_diag_handler *handler)
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{
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module_put(handler->owner);
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}
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static void sock_diag_broadcast_destroy_work(struct work_struct *work)
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{
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struct broadcast_sk *bsk =
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container_of(work, struct broadcast_sk, work);
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struct sock *sk = bsk->sk;
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const struct sock_diag_handler *hndl;
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struct sk_buff *skb;
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const enum sknetlink_groups group = sock_diag_destroy_group(sk);
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int err = -1;
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WARN_ON(group == SKNLGRP_NONE);
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skb = nlmsg_new(sock_diag_nlmsg_size(), GFP_KERNEL);
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if (!skb)
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goto out;
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hndl = sock_diag_lock_handler(sk->sk_family);
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if (hndl) {
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if (hndl->get_info)
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err = hndl->get_info(skb, sk);
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sock_diag_unlock_handler(hndl);
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}
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if (!err)
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nlmsg_multicast(sock_net(sk)->diag_nlsk, skb, 0, group,
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GFP_KERNEL);
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else
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kfree_skb(skb);
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out:
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sk_destruct(sk);
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kfree(bsk);
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}
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void sock_diag_broadcast_destroy(struct sock *sk)
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{
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/* Note, this function is often called from an interrupt context. */
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struct broadcast_sk *bsk =
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kmalloc(sizeof(struct broadcast_sk), GFP_ATOMIC);
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if (!bsk)
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return sk_destruct(sk);
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bsk->sk = sk;
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INIT_WORK(&bsk->work, sock_diag_broadcast_destroy_work);
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queue_work(broadcast_wq, &bsk->work);
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}
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void sock_diag_register_inet_compat(const struct sock_diag_inet_compat *ptr)
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{
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xchg(&inet_rcv_compat, RCU_INITIALIZER(ptr));
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}
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EXPORT_SYMBOL_GPL(sock_diag_register_inet_compat);
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void sock_diag_unregister_inet_compat(const struct sock_diag_inet_compat *ptr)
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{
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const struct sock_diag_inet_compat *old;
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old = unrcu_pointer(xchg(&inet_rcv_compat, NULL));
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WARN_ON_ONCE(old != ptr);
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}
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EXPORT_SYMBOL_GPL(sock_diag_unregister_inet_compat);
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int sock_diag_register(const struct sock_diag_handler *hndl)
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{
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int family = hndl->family;
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if (family >= AF_MAX)
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return -EINVAL;
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return !cmpxchg((const struct sock_diag_handler **)
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&sock_diag_handlers[family],
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NULL, hndl) ? 0 : -EBUSY;
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}
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EXPORT_SYMBOL_GPL(sock_diag_register);
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void sock_diag_unregister(const struct sock_diag_handler *hndl)
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{
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int family = hndl->family;
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if (family >= AF_MAX)
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return;
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xchg((const struct sock_diag_handler **)&sock_diag_handlers[family],
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NULL);
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}
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EXPORT_SYMBOL_GPL(sock_diag_unregister);
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static int __sock_diag_cmd(struct sk_buff *skb, struct nlmsghdr *nlh)
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{
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int err;
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struct sock_diag_req *req = nlmsg_data(nlh);
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const struct sock_diag_handler *hndl;
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if (nlmsg_len(nlh) < sizeof(*req))
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return -EINVAL;
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if (req->sdiag_family >= AF_MAX)
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return -EINVAL;
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req->sdiag_family = array_index_nospec(req->sdiag_family, AF_MAX);
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if (!rcu_access_pointer(sock_diag_handlers[req->sdiag_family]))
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sock_load_diag_module(req->sdiag_family, 0);
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hndl = sock_diag_lock_handler(req->sdiag_family);
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if (hndl == NULL)
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return -ENOENT;
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if (nlh->nlmsg_type == SOCK_DIAG_BY_FAMILY)
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err = hndl->dump(skb, nlh);
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else if (nlh->nlmsg_type == SOCK_DESTROY && hndl->destroy)
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err = hndl->destroy(skb, nlh);
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else
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err = -EOPNOTSUPP;
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sock_diag_unlock_handler(hndl);
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return err;
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}
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static int sock_diag_rcv_msg(struct sk_buff *skb, struct nlmsghdr *nlh,
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struct netlink_ext_ack *extack)
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{
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const struct sock_diag_inet_compat *ptr;
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int ret;
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switch (nlh->nlmsg_type) {
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case TCPDIAG_GETSOCK:
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case DCCPDIAG_GETSOCK:
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if (!rcu_access_pointer(inet_rcv_compat))
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sock_load_diag_module(AF_INET, 0);
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rcu_read_lock();
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ptr = rcu_dereference(inet_rcv_compat);
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if (ptr && !try_module_get(ptr->owner))
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ptr = NULL;
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rcu_read_unlock();
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ret = -EOPNOTSUPP;
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if (ptr) {
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ret = ptr->fn(skb, nlh);
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module_put(ptr->owner);
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}
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return ret;
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case SOCK_DIAG_BY_FAMILY:
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case SOCK_DESTROY:
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return __sock_diag_cmd(skb, nlh);
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default:
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return -EINVAL;
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}
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}
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static void sock_diag_rcv(struct sk_buff *skb)
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{
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netlink_rcv_skb(skb, &sock_diag_rcv_msg);
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}
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static int sock_diag_bind(struct net *net, int group)
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{
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switch (group) {
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case SKNLGRP_INET_TCP_DESTROY:
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case SKNLGRP_INET_UDP_DESTROY:
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if (!rcu_access_pointer(sock_diag_handlers[AF_INET]))
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sock_load_diag_module(AF_INET, 0);
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break;
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case SKNLGRP_INET6_TCP_DESTROY:
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case SKNLGRP_INET6_UDP_DESTROY:
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if (!rcu_access_pointer(sock_diag_handlers[AF_INET6]))
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sock_load_diag_module(AF_INET6, 0);
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break;
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}
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return 0;
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}
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int sock_diag_destroy(struct sock *sk, int err)
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{
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if (!ns_capable(sock_net(sk)->user_ns, CAP_NET_ADMIN))
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return -EPERM;
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if (!sk->sk_prot->diag_destroy)
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return -EOPNOTSUPP;
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return sk->sk_prot->diag_destroy(sk, err);
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}
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EXPORT_SYMBOL_GPL(sock_diag_destroy);
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static int __net_init diag_net_init(struct net *net)
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{
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struct netlink_kernel_cfg cfg = {
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.groups = SKNLGRP_MAX,
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.input = sock_diag_rcv,
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.bind = sock_diag_bind,
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.flags = NL_CFG_F_NONROOT_RECV,
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};
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net->diag_nlsk = netlink_kernel_create(net, NETLINK_SOCK_DIAG, &cfg);
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return net->diag_nlsk == NULL ? -ENOMEM : 0;
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}
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static void __net_exit diag_net_exit(struct net *net)
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{
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netlink_kernel_release(net->diag_nlsk);
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net->diag_nlsk = NULL;
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}
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static struct pernet_operations diag_net_ops = {
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.init = diag_net_init,
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.exit = diag_net_exit,
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};
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static int __init sock_diag_init(void)
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{
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broadcast_wq = alloc_workqueue("sock_diag_events", 0, 0);
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BUG_ON(!broadcast_wq);
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return register_pernet_subsys(&diag_net_ops);
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}
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device_initcall(sock_diag_init);
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