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286c72deab
linux-next/net/ipv6/ping.c
Eric Dumazet 286c72deab udp: must lock the socket in udp_disconnect() 
Baozeng Ding reported KASAN traces showing uses after free in
udp_lib_get_port() and other related UDP functions.

A CONFIG_DEBUG_PAGEALLOC=y kernel would eventually crash.

I could write a reproducer with two threads doing :

static int sock_fd;
static void *thr1(void *arg)
{
	for (;;) {
		connect(sock_fd, (const struct sockaddr *)arg,
			sizeof(struct sockaddr_in));
	}
}

static void *thr2(void *arg)
{
	struct sockaddr_in unspec;

	for (;;) {
		memset(&unspec, 0, sizeof(unspec));
	        connect(sock_fd, (const struct sockaddr *)&unspec,
			sizeof(unspec));
        }
}

Problem is that udp_disconnect() could run without holding socket lock,
and this was causing list corruptions.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Reported-by: Baozeng Ding <sploving1@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2016-10-20 14:45:52 -04:00

286 lines
7.5 KiB
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/*
* INET An implementation of the TCP/IP protocol suite for the LINUX
* operating system. INET is implemented using the BSD Socket
* interface as the means of communication with the user level.
*
* "Ping" sockets
*
* 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.
*
* Based on ipv4/ping.c code.
*
* Authors: Lorenzo Colitti (IPv6 support)
* Vasiliy Kulikov / Openwall (IPv4 implementation, for Linux 2.6),
* Pavel Kankovsky (IPv4 implementation, for Linux 2.4.32)
*
*/
#include <net/addrconf.h>
#include <net/ipv6.h>
#include <net/ip6_route.h>
#include <net/protocol.h>
#include <net/udp.h>
#include <net/transp_v6.h>
#include <net/ping.h>
/* Compatibility glue so we can support IPv6 when it's compiled as a module */
static int dummy_ipv6_recv_error(struct sock *sk, struct msghdr *msg, int len,
int *addr_len)
{
return -EAFNOSUPPORT;
}
static void dummy_ip6_datagram_recv_ctl(struct sock *sk, struct msghdr *msg,
struct sk_buff *skb)
{
}
static int dummy_icmpv6_err_convert(u8 type, u8 code, int *err)
{
return -EAFNOSUPPORT;
}
static void dummy_ipv6_icmp_error(struct sock *sk, struct sk_buff *skb, int err,
__be16 port, u32 info, u8 *payload) {}
static int dummy_ipv6_chk_addr(struct net *net, const struct in6_addr *addr,
const struct net_device *dev, int strict)
{
return 0;
}
static int ping_v6_sendmsg(struct sock *sk, struct msghdr *msg, size_t len)
{
struct inet_sock *inet = inet_sk(sk);
struct ipv6_pinfo *np = inet6_sk(sk);
struct icmp6hdr user_icmph;
int addr_type;
struct in6_addr *daddr;
int oif = 0;
struct flowi6 fl6;
int err;
struct dst_entry *dst;
struct rt6_info *rt;
struct pingfakehdr pfh;
struct sockcm_cookie junk = {0};
struct ipcm6_cookie ipc6;
pr_debug("ping_v6_sendmsg(sk=%p,sk->num=%u)\n", inet, inet->inet_num);
err = ping_common_sendmsg(AF_INET6, msg, len, &user_icmph,
sizeof(user_icmph));
if (err)
return err;
if (msg->msg_name) {
DECLARE_SOCKADDR(struct sockaddr_in6 *, u, msg->msg_name);
if (msg->msg_namelen < sizeof(*u))
return -EINVAL;
if (u->sin6_family != AF_INET6) {
return -EAFNOSUPPORT;
}
daddr = &(u->sin6_addr);
if (__ipv6_addr_needs_scope_id(ipv6_addr_type(daddr)))
oif = u->sin6_scope_id;
} else {
if (sk->sk_state != TCP_ESTABLISHED)
return -EDESTADDRREQ;
daddr = &sk->sk_v6_daddr;
}
if (!oif)
oif = sk->sk_bound_dev_if;
if (!oif)
oif = np->sticky_pktinfo.ipi6_ifindex;
if (!oif && ipv6_addr_is_multicast(daddr))
oif = np->mcast_oif;
else if (!oif)
oif = np->ucast_oif;
addr_type = ipv6_addr_type(daddr);
if ((__ipv6_addr_needs_scope_id(addr_type) && !oif) ||
(addr_type & IPV6_ADDR_MAPPED) ||
(oif && sk->sk_bound_dev_if && oif != sk->sk_bound_dev_if))
return -EINVAL;
/* TODO: use ip6_datagram_send_ctl to get options from cmsg */
memset(&fl6, 0, sizeof(fl6));
fl6.flowi6_proto = IPPROTO_ICMPV6;
fl6.saddr = np->saddr;
fl6.daddr = *daddr;
fl6.flowi6_oif = oif;
fl6.flowi6_mark = sk->sk_mark;
fl6.fl6_icmp_type = user_icmph.icmp6_type;
fl6.fl6_icmp_code = user_icmph.icmp6_code;
security_sk_classify_flow(sk, flowi6_to_flowi(&fl6));
ipc6.tclass = np->tclass;
fl6.flowlabel = ip6_make_flowinfo(ipc6.tclass, fl6.flowlabel);
dst = ip6_sk_dst_lookup_flow(sk, &fl6, daddr);
if (IS_ERR(dst))
return PTR_ERR(dst);
rt = (struct rt6_info *) dst;
np = inet6_sk(sk);
if (!np) {
err = -EBADF;
goto dst_err_out;
}
if (!fl6.flowi6_oif && ipv6_addr_is_multicast(&fl6.daddr))
fl6.flowi6_oif = np->mcast_oif;
else if (!fl6.flowi6_oif)
fl6.flowi6_oif = np->ucast_oif;
pfh.icmph.type = user_icmph.icmp6_type;
pfh.icmph.code = user_icmph.icmp6_code;
pfh.icmph.checksum = 0;
pfh.icmph.un.echo.id = inet->inet_sport;
pfh.icmph.un.echo.sequence = user_icmph.icmp6_sequence;
pfh.msg = msg;
pfh.wcheck = 0;
pfh.family = AF_INET6;
ipc6.hlimit = ip6_sk_dst_hoplimit(np, &fl6, dst);
ipc6.dontfrag = np->dontfrag;
ipc6.opt = NULL;
lock_sock(sk);
err = ip6_append_data(sk, ping_getfrag, &pfh, len,
0, &ipc6, &fl6, rt,
MSG_DONTWAIT, &junk);
if (err) {
ICMP6_INC_STATS(sock_net(sk), rt->rt6i_idev,
ICMP6_MIB_OUTERRORS);
ip6_flush_pending_frames(sk);
} else {
err = icmpv6_push_pending_frames(sk, &fl6,
(struct icmp6hdr *) &pfh.icmph,
len);
}
release_sock(sk);
dst_err_out:
dst_release(dst);
if (err)
return err;
return len;
}
struct proto pingv6_prot = {
.name = "PINGv6",
.owner = THIS_MODULE,
.init = ping_init_sock,
.close = ping_close,
.connect = ip6_datagram_connect_v6_only,
.disconnect = __udp_disconnect,
.setsockopt = ipv6_setsockopt,
.getsockopt = ipv6_getsockopt,
.sendmsg = ping_v6_sendmsg,
.recvmsg = ping_recvmsg,
.bind = ping_bind,
.backlog_rcv = ping_queue_rcv_skb,
.hash = ping_hash,
.unhash = ping_unhash,
.get_port = ping_get_port,
.obj_size = sizeof(struct raw6_sock),
};
EXPORT_SYMBOL_GPL(pingv6_prot);
static struct inet_protosw pingv6_protosw = {
.type = SOCK_DGRAM,
.protocol = IPPROTO_ICMPV6,
.prot = &pingv6_prot,
.ops = &inet6_dgram_ops,
.flags = INET_PROTOSW_REUSE,
};
#ifdef CONFIG_PROC_FS
static void *ping_v6_seq_start(struct seq_file *seq, loff_t *pos)
{
return ping_seq_start(seq, pos, AF_INET6);
}
static int ping_v6_seq_show(struct seq_file *seq, void *v)
{
if (v == SEQ_START_TOKEN) {
seq_puts(seq, IPV6_SEQ_DGRAM_HEADER);
} else {
int bucket = ((struct ping_iter_state *) seq->private)->bucket;
struct inet_sock *inet = inet_sk(v);
__u16 srcp = ntohs(inet->inet_sport);
__u16 destp = ntohs(inet->inet_dport);
ip6_dgram_sock_seq_show(seq, v, srcp, destp, bucket);
}
return 0;
}
static struct ping_seq_afinfo ping_v6_seq_afinfo = {
.name = "icmp6",
.family = AF_INET6,
.seq_fops = &ping_seq_fops,
.seq_ops = {
.start = ping_v6_seq_start,
.show = ping_v6_seq_show,
.next = ping_seq_next,
.stop = ping_seq_stop,
},
};
static int __net_init ping_v6_proc_init_net(struct net *net)
{
return ping_proc_register(net, &ping_v6_seq_afinfo);
}
static void __net_init ping_v6_proc_exit_net(struct net *net)
{
return ping_proc_unregister(net, &ping_v6_seq_afinfo);
}
static struct pernet_operations ping_v6_net_ops = {
.init = ping_v6_proc_init_net,
.exit = ping_v6_proc_exit_net,
};
#endif
int __init pingv6_init(void)
{
#ifdef CONFIG_PROC_FS
int ret = register_pernet_subsys(&ping_v6_net_ops);
if (ret)
return ret;
#endif
pingv6_ops.ipv6_recv_error = ipv6_recv_error;
pingv6_ops.ip6_datagram_recv_common_ctl = ip6_datagram_recv_common_ctl;
pingv6_ops.ip6_datagram_recv_specific_ctl =
ip6_datagram_recv_specific_ctl;
pingv6_ops.icmpv6_err_convert = icmpv6_err_convert;
pingv6_ops.ipv6_icmp_error = ipv6_icmp_error;
pingv6_ops.ipv6_chk_addr = ipv6_chk_addr;
return inet6_register_protosw(&pingv6_protosw);
}
/* This never gets called because it's not possible to unload the ipv6 module,
* but just in case.
*/
void pingv6_exit(void)
{
pingv6_ops.ipv6_recv_error = dummy_ipv6_recv_error;
pingv6_ops.ip6_datagram_recv_common_ctl = dummy_ip6_datagram_recv_ctl;
pingv6_ops.ip6_datagram_recv_specific_ctl = dummy_ip6_datagram_recv_ctl;
pingv6_ops.icmpv6_err_convert = dummy_icmpv6_err_convert;
pingv6_ops.ipv6_icmp_error = dummy_ipv6_icmp_error;
pingv6_ops.ipv6_chk_addr = dummy_ipv6_chk_addr;
#ifdef CONFIG_PROC_FS
unregister_pernet_subsys(&ping_v6_net_ops);
#endif
inet6_unregister_protosw(&pingv6_protosw);
}
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