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Commit 9577d9f0 authored by Kuniyuki Iwashima's avatar Kuniyuki Iwashima Committed by Greg Kroah-Hartman
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udp: Call inet6_destroy_sock() in setsockopt(IPV6_ADDRFORM). 



commit 21985f43376cee092702d6cb963ff97a9d2ede68 upstream.

Commit 4b340ae2 ("IPv6: Complete IPV6_DONTFRAG support") forgot
to add a change to free inet6_sk(sk)->rxpmtu while converting an IPv6
socket into IPv4 with IPV6_ADDRFORM.  After conversion, sk_prot is
changed to udp_prot and ->destroy() never cleans it up, resulting in
a memory leak.

This is due to the discrepancy between inet6_destroy_sock() and
IPV6_ADDRFORM, so let's call inet6_destroy_sock() from IPV6_ADDRFORM
to remove the difference.

However, this is not enough for now because rxpmtu can be changed
without lock_sock() after commit 03485f2a ("udpv6: Add lockless
sendmsg() support").  We will fix this case in the following patch.

Note we will rename inet6_destroy_sock() to inet6_cleanup_sock() and
remove unnecessary inet6_destroy_sock() calls in sk_prot->destroy()
in the future.

Fixes: 4b340ae2 ("IPv6: Complete IPV6_DONTFRAG support")
Signed-off-by: default avatarKuniyuki Iwashima <kuniyu@amazon.com>
Signed-off-by: default avatarJakub Kicinski <kuba@kernel.org>
Signed-off-by: default avatarZiyang Xuan <william.xuanziyang@huawei.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 50c3bf38

include/net/ipv6.h

+1 −0
Original line number Diff line number Diff line
@@ -1040,6 +1040,7 @@ void ipv6_icmp_error(struct sock *sk, struct sk_buff *skb, int err, __be16 port, 
void ipv6_local_error(struct sock *sk, int err, struct flowi6 *fl6, u32 info);

void ipv6_local_rxpmtu(struct sock *sk, struct flowi6 *fl6, u32 mtu);



void inet6_cleanup_sock(struct sock *sk);

int inet6_release(struct socket *sock);

int inet6_bind(struct socket *sock, struct sockaddr *uaddr, int addr_len);

int inet6_getname(struct socket *sock, struct sockaddr *uaddr,

net/ipv6/af_inet6.c

+6 −0
Original line number Diff line number Diff line
@@ -502,6 +502,12 @@ void inet6_destroy_sock(struct sock *sk) 
}

EXPORT_SYMBOL_GPL(inet6_destroy_sock);



void inet6_cleanup_sock(struct sock *sk)

{

	inet6_destroy_sock(sk);

}

EXPORT_SYMBOL_GPL(inet6_cleanup_sock);



/*

 *	This does both peername and sockname.

 */

net/ipv6/ipv6_sockglue.c

+8 −12
Original line number Diff line number Diff line
@@ -178,9 +178,6 @@ static int do_ipv6_setsockopt(struct sock *sk, int level, int optname, 
		if (optlen < sizeof(int))

			goto e_inval;

		if (val == PF_INET) {

			struct ipv6_txoptions *opt;

			struct sk_buff *pktopt;



			if (sk->sk_type == SOCK_RAW)

				break;
@@ -211,7 +208,6 @@ static int do_ipv6_setsockopt(struct sock *sk, int level, int optname, 
				break;

			}



			fl6_free_socklist(sk);

			__ipv6_sock_mc_close(sk);

			__ipv6_sock_ac_close(sk);
@@ -246,14 +242,14 @@ static int do_ipv6_setsockopt(struct sock *sk, int level, int optname, 
				sk->sk_socket->ops = &inet_dgram_ops;

				sk->sk_family = PF_INET;

			}

			opt = xchg((__force struct ipv6_txoptions **)&np->opt,

				   NULL);

			if (opt) {

				atomic_sub(opt->tot_len, &sk->sk_omem_alloc);

				txopt_put(opt);

			}

			pktopt = xchg(&np->pktoptions, NULL);

			kfree_skb(pktopt);



			/* Disable all options not to allocate memory anymore,

			 * but there is still a race.  See the lockless path

			 * in udpv6_sendmsg() and ipv6_local_rxpmtu().

			 */

			np->rxopt.all = 0;



			inet6_cleanup_sock(sk);



			/*

			 * ... and add it to the refcnt debug socks count