linux/net/ipv4/udplite.c
Kuniyuki Iwashima d38afeec26 tcp/udp: Call inet6_destroy_sock() in IPv6 sk->sk_destruct().
Originally, inet6_sk(sk)->XXX were changed under lock_sock(), so we were
able to clean them up by calling inet6_destroy_sock() during the IPv6 ->
IPv4 conversion by IPV6_ADDRFORM.  However, commit 03485f2adc ("udpv6:
Add lockless sendmsg() support") added a lockless memory allocation path,
which could cause a memory leak:

setsockopt(IPV6_ADDRFORM)                 sendmsg()
+-----------------------+                 +-------+
- do_ipv6_setsockopt(sk, ...)             - udpv6_sendmsg(sk, ...)
  - sockopt_lock_sock(sk)                   ^._ called via udpv6_prot
    - lock_sock(sk)                             before WRITE_ONCE()
  - WRITE_ONCE(sk->sk_prot, &tcp_prot)
  - inet6_destroy_sock()                    - if (!corkreq)
  - sockopt_release_sock(sk)                  - ip6_make_skb(sk, ...)
    - release_sock(sk)                          ^._ lockless fast path for
                                                    the non-corking case

                                                - __ip6_append_data(sk, ...)
                                                  - ipv6_local_rxpmtu(sk, ...)
                                                    - xchg(&np->rxpmtu, skb)
                                                      ^._ rxpmtu is never freed.

                                                - goto out_no_dst;

                                            - lock_sock(sk)

For now, rxpmtu is only the case, but not to miss the future change
and a similar bug fixed in commit e27326009a ("net: ping6: Fix
memleak in ipv6_renew_options()."), let's set a new function to IPv6
sk->sk_destruct() and call inet6_cleanup_sock() there.  Since the
conversion does not change sk->sk_destruct(), we can guarantee that
we can clean up IPv6 resources finally.

We can now remove all inet6_destroy_sock() calls from IPv6 protocol
specific ->destroy() functions, but such changes are invasive to
backport.  So they can be posted as a follow-up later for net-next.

Fixes: 03485f2adc ("udpv6: Add lockless sendmsg() support")
Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2022-10-12 17:50:37 -07:00

135 lines
3.1 KiB
C

// SPDX-License-Identifier: GPL-2.0-or-later
/*
* UDPLITE An implementation of the UDP-Lite protocol (RFC 3828).
*
* Authors: Gerrit Renker <gerrit@erg.abdn.ac.uk>
*
* Changes:
* Fixes:
*/
#define pr_fmt(fmt) "UDPLite: " fmt
#include <linux/export.h>
#include <linux/proc_fs.h>
#include "udp_impl.h"
struct udp_table udplite_table __read_mostly;
EXPORT_SYMBOL(udplite_table);
/* Designate sk as UDP-Lite socket */
static int udplite_sk_init(struct sock *sk)
{
udp_init_sock(sk);
udp_sk(sk)->pcflag = UDPLITE_BIT;
return 0;
}
static int udplite_rcv(struct sk_buff *skb)
{
return __udp4_lib_rcv(skb, &udplite_table, IPPROTO_UDPLITE);
}
static int udplite_err(struct sk_buff *skb, u32 info)
{
return __udp4_lib_err(skb, info, &udplite_table);
}
static const struct net_protocol udplite_protocol = {
.handler = udplite_rcv,
.err_handler = udplite_err,
.no_policy = 1,
};
struct proto udplite_prot = {
.name = "UDP-Lite",
.owner = THIS_MODULE,
.close = udp_lib_close,
.connect = ip4_datagram_connect,
.disconnect = udp_disconnect,
.ioctl = udp_ioctl,
.init = udplite_sk_init,
.destroy = udp_destroy_sock,
.setsockopt = udp_setsockopt,
.getsockopt = udp_getsockopt,
.sendmsg = udp_sendmsg,
.recvmsg = udp_recvmsg,
.sendpage = udp_sendpage,
.hash = udp_lib_hash,
.unhash = udp_lib_unhash,
.rehash = udp_v4_rehash,
.get_port = udp_v4_get_port,
.memory_allocated = &udp_memory_allocated,
.per_cpu_fw_alloc = &udp_memory_per_cpu_fw_alloc,
.sysctl_mem = sysctl_udp_mem,
.obj_size = sizeof(struct udp_sock),
.h.udp_table = &udplite_table,
};
EXPORT_SYMBOL(udplite_prot);
static struct inet_protosw udplite4_protosw = {
.type = SOCK_DGRAM,
.protocol = IPPROTO_UDPLITE,
.prot = &udplite_prot,
.ops = &inet_dgram_ops,
.flags = INET_PROTOSW_PERMANENT,
};
#ifdef CONFIG_PROC_FS
static struct udp_seq_afinfo udplite4_seq_afinfo = {
.family = AF_INET,
.udp_table = &udplite_table,
};
static int __net_init udplite4_proc_init_net(struct net *net)
{
if (!proc_create_net_data("udplite", 0444, net->proc_net, &udp_seq_ops,
sizeof(struct udp_iter_state), &udplite4_seq_afinfo))
return -ENOMEM;
return 0;
}
static void __net_exit udplite4_proc_exit_net(struct net *net)
{
remove_proc_entry("udplite", net->proc_net);
}
static struct pernet_operations udplite4_net_ops = {
.init = udplite4_proc_init_net,
.exit = udplite4_proc_exit_net,
};
static __init int udplite4_proc_init(void)
{
return register_pernet_subsys(&udplite4_net_ops);
}
#else
static inline int udplite4_proc_init(void)
{
return 0;
}
#endif
void __init udplite4_register(void)
{
udp_table_init(&udplite_table, "UDP-Lite");
if (proto_register(&udplite_prot, 1))
goto out_register_err;
if (inet_add_protocol(&udplite_protocol, IPPROTO_UDPLITE) < 0)
goto out_unregister_proto;
inet_register_protosw(&udplite4_protosw);
if (udplite4_proc_init())
pr_err("%s: Cannot register /proc!\n", __func__);
return;
out_unregister_proto:
proto_unregister(&udplite_prot);
out_register_err:
pr_crit("%s: Cannot add UDP-Lite protocol\n", __func__);
}