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linux_dsm_epyc7002/net/ipv4/udp_diag.c
Lorenzo Colitti 747569b0a7 net: diag: document swapped src/dst in udp_dump_one. 
Since its inception, udp_dump_one has had a bug where userspace
needs to swap src and dst addresses and ports in order to find
the socket it wants. This is because it passes the socket source
address to __udp[46]_lib_lookup's saddr argument, but those
functions are intended to find local sockets matching received
packets, so saddr is the remote address, not the local address.

This can no longer be fixed for backwards compatibility reasons,
so add a brief comment explaining that this is the case. This
will avoid confusion and help ensure SOCK_DIAG implementations
of new protocols don't have the same problem.

Fixes: a925aa00a5 ("udp_diag: Implement the get_exact dumping functionality")
Signed-off-by: Lorenzo Colitti <lorenzo@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2018-10-28 19:27:21 -07:00

307 lines
7.5 KiB
C
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/*
* udp_diag.c Module for monitoring UDP transport protocols sockets.
*
* Authors: Pavel Emelyanov, <xemul@parallels.com>
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version
* 2 of the License, or (at your option) any later version.
*/
#include <linux/module.h>
#include <linux/inet_diag.h>
#include <linux/udp.h>
#include <net/udp.h>
#include <net/udplite.h>
#include <linux/sock_diag.h>
static int sk_diag_dump(struct sock *sk, struct sk_buff *skb,
struct netlink_callback *cb,
const struct inet_diag_req_v2 *req,
struct nlattr *bc, bool net_admin)
{
if (!inet_diag_bc_sk(bc, sk))
return 0;
return inet_sk_diag_fill(sk, NULL, skb, req,
sk_user_ns(NETLINK_CB(cb->skb).sk),
NETLINK_CB(cb->skb).portid,
cb->nlh->nlmsg_seq, NLM_F_MULTI, cb->nlh, net_admin);
}
static int udp_dump_one(struct udp_table *tbl, struct sk_buff *in_skb,
const struct nlmsghdr *nlh,
const struct inet_diag_req_v2 *req)
{
int err = -EINVAL;
struct sock *sk = NULL;
struct sk_buff *rep;
struct net *net = sock_net(in_skb->sk);
rcu_read_lock();
if (req->sdiag_family == AF_INET)
/* src and dst are swapped for historical reasons */
sk = __udp4_lib_lookup(net,
req->id.idiag_src[0], req->id.idiag_sport,
req->id.idiag_dst[0], req->id.idiag_dport,
req->id.idiag_if, 0, tbl, NULL);
#if IS_ENABLED(CONFIG_IPV6)
else if (req->sdiag_family == AF_INET6)
sk = __udp6_lib_lookup(net,
(struct in6_addr *)req->id.idiag_src,
req->id.idiag_sport,
(struct in6_addr *)req->id.idiag_dst,
req->id.idiag_dport,
req->id.idiag_if, 0, tbl, NULL);
#endif
if (sk && !refcount_inc_not_zero(&sk->sk_refcnt))
sk = NULL;
rcu_read_unlock();
err = -ENOENT;
if (!sk)
goto out_nosk;
err = sock_diag_check_cookie(sk, req->id.idiag_cookie);
if (err)
goto out;
err = -ENOMEM;
rep = nlmsg_new(sizeof(struct inet_diag_msg) +
sizeof(struct inet_diag_meminfo) + 64,
GFP_KERNEL);
if (!rep)
goto out;
err = inet_sk_diag_fill(sk, NULL, rep, req,
sk_user_ns(NETLINK_CB(in_skb).sk),
NETLINK_CB(in_skb).portid,
nlh->nlmsg_seq, 0, nlh,
netlink_net_capable(in_skb, CAP_NET_ADMIN));
if (err < 0) {
WARN_ON(err == -EMSGSIZE);
kfree_skb(rep);
goto out;
}
err = netlink_unicast(net->diag_nlsk, rep, NETLINK_CB(in_skb).portid,
MSG_DONTWAIT);
if (err > 0)
err = 0;
out:
if (sk)
sock_put(sk);
out_nosk:
return err;
}
static void udp_dump(struct udp_table *table, struct sk_buff *skb,
struct netlink_callback *cb,
const struct inet_diag_req_v2 *r, struct nlattr *bc)
{
bool net_admin = netlink_net_capable(cb->skb, CAP_NET_ADMIN);
struct net *net = sock_net(skb->sk);
int num, s_num, slot, s_slot;
s_slot = cb->args[0];
num = s_num = cb->args[1];
for (slot = s_slot; slot <= table->mask; s_num = 0, slot++) {
struct udp_hslot *hslot = &table->hash[slot];
struct sock *sk;
num = 0;
if (hlist_empty(&hslot->head))
continue;
spin_lock_bh(&hslot->lock);
sk_for_each(sk, &hslot->head) {
struct inet_sock *inet = inet_sk(sk);
if (!net_eq(sock_net(sk), net))
continue;
if (num < s_num)
goto next;
if (!(r->idiag_states & (1 << sk->sk_state)))
goto next;
if (r->sdiag_family != AF_UNSPEC &&
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) {
spin_unlock_bh(&hslot->lock);
goto done;
}
next:
num++;
}
spin_unlock_bh(&hslot->lock);
}
done:
cb->args[0] = slot;
cb->args[1] = num;
}
static void udp_diag_dump(struct sk_buff *skb, struct netlink_callback *cb,
const struct inet_diag_req_v2 *r, struct nlattr *bc)
{
udp_dump(&udp_table, skb, cb, r, bc);
}
static int udp_diag_dump_one(struct sk_buff *in_skb, const struct nlmsghdr *nlh,
const struct inet_diag_req_v2 *req)
{
return udp_dump_one(&udp_table, in_skb, nlh, req);
}
static void udp_diag_get_info(struct sock *sk, struct inet_diag_msg *r,
void *info)
{
r->idiag_rqueue = udp_rqueue_get(sk);
r->idiag_wqueue = sk_wmem_alloc_get(sk);
}
#ifdef CONFIG_INET_DIAG_DESTROY
static int __udp_diag_destroy(struct sk_buff *in_skb,
const struct inet_diag_req_v2 *req,
struct udp_table *tbl)
{
struct net *net = sock_net(in_skb->sk);
struct sock *sk;
int err;
rcu_read_lock();
if (req->sdiag_family == AF_INET)
sk = __udp4_lib_lookup(net,
req->id.idiag_dst[0], req->id.idiag_dport,
req->id.idiag_src[0], req->id.idiag_sport,
req->id.idiag_if, 0, tbl, NULL);
#if IS_ENABLED(CONFIG_IPV6)
else if (req->sdiag_family == AF_INET6) {
if (ipv6_addr_v4mapped((struct in6_addr *)req->id.idiag_dst) &&
ipv6_addr_v4mapped((struct in6_addr *)req->id.idiag_src))
sk = __udp4_lib_lookup(net,
req->id.idiag_dst[3], req->id.idiag_dport,
req->id.idiag_src[3], req->id.idiag_sport,
req->id.idiag_if, 0, tbl, NULL);
else
sk = __udp6_lib_lookup(net,
(struct in6_addr *)req->id.idiag_dst,
req->id.idiag_dport,
(struct in6_addr *)req->id.idiag_src,
req->id.idiag_sport,
req->id.idiag_if, 0, tbl, NULL);
}
#endif
else {
rcu_read_unlock();
return -EINVAL;
}
if (sk && !refcount_inc_not_zero(&sk->sk_refcnt))
sk = NULL;
rcu_read_unlock();
if (!sk)
return -ENOENT;
if (sock_diag_check_cookie(sk, req->id.idiag_cookie)) {
sock_put(sk);
return -ENOENT;
}
err = sock_diag_destroy(sk, ECONNABORTED);
sock_put(sk);
return err;
}
static int udp_diag_destroy(struct sk_buff *in_skb,
const struct inet_diag_req_v2 *req)
{
return __udp_diag_destroy(in_skb, req, &udp_table);
}
static int udplite_diag_destroy(struct sk_buff *in_skb,
const struct inet_diag_req_v2 *req)
{
return __udp_diag_destroy(in_skb, req, &udplite_table);
}
#endif
static const struct inet_diag_handler udp_diag_handler = {
.dump = udp_diag_dump,
.dump_one = udp_diag_dump_one,
.idiag_get_info = udp_diag_get_info,
.idiag_type = IPPROTO_UDP,
.idiag_info_size = 0,
#ifdef CONFIG_INET_DIAG_DESTROY
.destroy = udp_diag_destroy,
#endif
};
static void udplite_diag_dump(struct sk_buff *skb, struct netlink_callback *cb,
const struct inet_diag_req_v2 *r,
struct nlattr *bc)
{
udp_dump(&udplite_table, skb, cb, r, bc);
}
static int udplite_diag_dump_one(struct sk_buff *in_skb, const struct nlmsghdr *nlh,
const struct inet_diag_req_v2 *req)
{
return udp_dump_one(&udplite_table, in_skb, nlh, req);
}
static const struct inet_diag_handler udplite_diag_handler = {
.dump = udplite_diag_dump,
.dump_one = udplite_diag_dump_one,
.idiag_get_info = udp_diag_get_info,
.idiag_type = IPPROTO_UDPLITE,
.idiag_info_size = 0,
#ifdef CONFIG_INET_DIAG_DESTROY
.destroy = udplite_diag_destroy,
#endif
};
static int __init udp_diag_init(void)
{
int err;
err = inet_diag_register(&udp_diag_handler);
if (err)
goto out;
err = inet_diag_register(&udplite_diag_handler);
if (err)
goto out_lite;
out:
return err;
out_lite:
inet_diag_unregister(&udp_diag_handler);
goto out;
}
static void __exit udp_diag_exit(void)
{
inet_diag_unregister(&udplite_diag_handler);
inet_diag_unregister(&udp_diag_handler);
}
module_init(udp_diag_init);
module_exit(udp_diag_exit);
MODULE_LICENSE("GPL");
MODULE_ALIAS_NET_PF_PROTO_TYPE(PF_NETLINK, NETLINK_SOCK_DIAG, 2-17 /* AF_INET - IPPROTO_UDP */);
MODULE_ALIAS_NET_PF_PROTO_TYPE(PF_NETLINK, NETLINK_SOCK_DIAG, 2-136 /* AF_INET - IPPROTO_UDPLITE */);
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