linux-stable/net/ipv4/raw_diag.c
Eric Dumazet af185d8c76 raw: complete rcu conversion
raw_diag_dump() can use rcu_read_lock() instead of read_lock()

Now the hashinfo lock is only used from process context,
in write mode only, we can convert it to a spinlock,
and we do not need to block BH anymore.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Link: https://lore.kernel.org/r/20220620100509.3493504-1-eric.dumazet@gmail.com
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
2022-06-21 11:38:29 +02:00

263 lines
6.3 KiB
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, 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_nulls_head *hlist;
struct hlist_nulls_node *hnode;
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_nulls_for_each(sk, hnode, 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,
struct nlattr *bc, bool net_admin)
{
if (!inet_diag_bc_sk(bc, 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);
struct inet_diag_dump_data *cb_data;
struct hlist_nulls_head *hlist;
struct hlist_nulls_node *hnode;
int num, s_num, slot, s_slot;
struct sock *sk = NULL;
struct nlattr *bc;
if (IS_ERR(hashinfo))
return;
cb_data = cb->data;
bc = cb_data->inet_diag_nla_bc;
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_nulls_for_each(sk, hnode, 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, bc, 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 = {
.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_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 */);