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udp: Call inet6_destroy_sock() in setsockopt(IPV6_ADDRFORM).

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Commit 4b340ae20d ("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 03485f2adc ("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: 4b340ae20d ("IPv6: Complete IPV6_DONTFRAG support")
Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
This commit is contained in:
Kuniyuki Iwashima 2022-10-06 11:53:46 -07:00 committed by Jakub Kicinski
parent 3c52c6bb83
commit 21985f4337
3 changed files with 15 additions and 12 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

1
include/net/ipv6.h
View File

@ -1182,6 +1182,7 @@ 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,

6
net/ipv6/af_inet6.c
View File

@ -510,6 +510,12 @@ 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.
*/

20
net/ipv6/ipv6_sockglue.c
View File

@ -431,9 +431,6 @@ 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;
@ -464,7 +461,6 @@ 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);
@ -501,14 +497,14 @@ 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