Messages in this thread | | | From | Eric Dumazet <> | Date | Tue, 27 Sep 2022 09:50:04 -0700 | Subject | Re: [PATCH v1 net 3/5] tcp/udp: Call inet6_destroy_sock() in IPv4 sk_prot->destroy(). |
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On Tue, Sep 27, 2022 at 9:13 AM Kuniyuki Iwashima <kuniyu@amazon.com> wrote: > > 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 03485f2adcde ("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, ...) > - lock_sock(sk) ^._ called via udpv6_prot > - WRITE_ONCE(sk->sk_prot, &tcp_prot) before WRITE_ONCE() > - inet6_destroy_sock() > - release_sock(sk) - ip6_make_skb(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. > > - lock_sock(sk) > > For now, rxpmtu is only the case, but let's call inet6_destroy_sock() > in both TCP/UDP v4 destroy functions not to miss the future change. > > We can consolidate TCP/UDP v4/v6 destroy functions, but such changes > are too invasive to backport to stable. So, they can be posted as a > follow-up later for net-next. > > Fixes: 03485f2adcde ("udpv6: Add lockless sendmsg() support") > Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com> > --- > Cc: Vladislav Yasevich <vyasevic@redhat.com> > --- > net/ipv4/tcp_ipv4.c | 5 +++++ > net/ipv4/udp.c | 6 ++++++ > net/ipv6/tcp_ipv6.c | 1 - > 3 files changed, 11 insertions(+), 1 deletion(-) > > diff --git a/net/ipv4/tcp_ipv4.c b/net/ipv4/tcp_ipv4.c > index 5b019ba2b9d2..035b6c52a243 100644 > --- a/net/ipv4/tcp_ipv4.c > +++ b/net/ipv4/tcp_ipv4.c > @@ -2263,6 +2263,11 @@ void tcp_v4_destroy_sock(struct sock *sk) > tcp_saved_syn_free(tp); > > sk_sockets_allocated_dec(sk); > + > +#if IS_ENABLED(CONFIG_IPV6) > + if (sk->sk_prot_creator == &tcpv6_prot) > + inet6_destroy_sock(sk); > +#endif > }
This is ugly, and will not compile with CONFIG_IPV6=m, right ?
> EXPORT_SYMBOL(tcp_v4_destroy_sock); > > diff --git a/net/ipv4/udp.c b/net/ipv4/udp.c > index 560d9eadeaa5..cdf131c0a819 100644 > --- a/net/ipv4/udp.c > +++ b/net/ipv4/udp.c > @@ -115,6 +115,7 @@ > #include <net/udp_tunnel.h> > #if IS_ENABLED(CONFIG_IPV6) > #include <net/ipv6_stubs.h> > +#include <net/transp_v6.h> > #endif > > struct udp_table udp_table __read_mostly; > @@ -2666,6 +2667,11 @@ void udp_destroy_sock(struct sock *sk) > if (up->encap_enabled) > static_branch_dec(&udp_encap_needed_key); > } > + > +#if IS_ENABLED(CONFIG_IPV6) > + if (sk->sk_prot_creator == &udpv6_prot) > + inet6_destroy_sock(sk); > +#endif > } > > /* > diff --git a/net/ipv6/tcp_ipv6.c b/net/ipv6/tcp_ipv6.c > index e54eee80ce5f..1ff6a92f7774 100644 > --- a/net/ipv6/tcp_ipv6.c > +++ b/net/ipv6/tcp_ipv6.c > @@ -1945,7 +1945,6 @@ static int tcp_v6_init_sock(struct sock *sk) > static void tcp_v6_destroy_sock(struct sock *sk) > { > tcp_v4_destroy_sock(sk); > - inet6_destroy_sock(sk); > } > > #ifdef CONFIG_PROC_FS > -- > 2.30.2 >
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