1. Patchew
  2. linux
  3. [PATCH v1 net 0/5] tcp/udp: Fix memory leaks and data races around IPV6_ADDRFORM.
  4. View patch

[PATCH v1 net 3/5] tcp/udp: Call inet6_destroy_sock() in IPv4 sk_prot->destroy().

Kuniyuki Iwashima posted 5 patches 3 years, 6 months ago
There is a newer version of this series
[PATCH v1 net 3/5] tcp/udp: Call inet6_destroy_sock() in IPv4 sk_prot->destroy().
Posted by Kuniyuki Iwashima 3 years, 6 months ago 
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
 }
 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
Re: [PATCH v1 net 3/5] tcp/udp: Call inet6_destroy_sock() in IPv4 sk_prot->destroy().
Posted by Eric Dumazet 3 years, 6 months ago 
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
>
Re: [PATCH v1 net 3/5] tcp/udp: Call inet6_destroy_sock() in IPv4 sk_prot->destroy().
Posted by Kuniyuki Iwashima 3 years, 6 months ago 
From:   Eric Dumazet <edumazet@google.com>
Date:   Tue, 27 Sep 2022 09:50:04 -0700
> 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 ?

Ah, exactly...

ld: net/ipv4/tcp_ipv4.o: in function `tcp_v4_destroy_sock':
/mnt/ec2-user/kernel/214_tcp_ipv6_renew_options_memleak/net/ipv4/tcp_ipv4.c:2290: undefined reference to `tcpv6_prot'
ld: /mnt/ec2-user/kernel/214_tcp_ipv6_renew_options_memleak/net/ipv4/tcp_ipv4.c:2291: undefined reference to `inet6_destroy_sock'
ld: net/ipv4/udp.o: in function `udp_destroy_sock':
/mnt/ec2-user/kernel/214_tcp_ipv6_renew_options_memleak/net/ipv4/udp.c:2660: undefined reference to `udpv6_prot'
ld: /mnt/ec2-user/kernel/214_tcp_ipv6_renew_options_memleak/net/ipv4/udp.c:2661: undefined reference to `inet6_destroy_sock'

So, do we have to move these 4 under net/ipv4/ with #ifdef CONFIG_IPv6 ?


> >  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
> >

Patchew 2.1-devel-ea86937

© 2016 - 2026 Red Hat, Inc.