Messages in this thread Patch in this message | | | From | Kuniyuki Iwashima <> | Subject | [PATCH v1 net 3/5] tcp/udp: Call inet6_destroy_sock() in IPv4 sk_prot->destroy(). | Date | Tue, 27 Sep 2022 09:12:07 -0700 |
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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
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