From c2fc6443b6478ff5fa9587b1900a90cda03b4031 Mon Sep 17 00:00:00 2001 From: Geliang Tang Date: Thu, 6 Jun 2024 10:06:17 +0800 Subject: [PATCH 1/2] mptcp: add sk_stop_timer_sync helper stable inclusion from stable-v4.19.312 commit 9c382bc16fa8f7499b0663398437e125cf4f763b category: bugfix bugzilla: https://gitee.com/src-openeuler/kernel/issues/I9QG5Z CVE: CVE-2024-35910 Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=9c382bc16fa8f7499b0663398437e125cf4f763b --------------------------- [ Upstream commit 08b81d873126b413cda511b1ea1cbb0e99938bbd ] This patch added a new helper sk_stop_timer_sync, it deactivates a timer like sk_stop_timer, but waits for the handler to finish. Acked-by: Paolo Abeni Signed-off-by: Geliang Tang Reviewed-by: Mat Martineau Signed-off-by: David S. Miller Stable-dep-of: 151c9c724d05 ("tcp: properly terminate timers for kernel sockets") Signed-off-by: Sasha Levin Conflicts: net/core/sock.c [This is because we backport 584f3742890e.] Signed-off-by: Liu Jian --- include/net/sock.h | 2 ++ net/core/sock.c | 7 +++++++ 2 files changed, 9 insertions(+) diff --git a/include/net/sock.h b/include/net/sock.h index a1bfb777a1af..e6d74da86930 100644 --- a/include/net/sock.h +++ b/include/net/sock.h @@ -2241,6 +2241,8 @@ void sk_reset_timer(struct sock *sk, struct timer_list *timer, void sk_stop_timer(struct sock *sk, struct timer_list *timer); +void sk_stop_timer_sync(struct sock *sk, struct timer_list *timer); + int __sk_queue_drop_skb(struct sock *sk, struct sk_buff_head *sk_queue, struct sk_buff *skb, unsigned int flags, void (*destructor)(struct sock *sk, diff --git a/net/core/sock.c b/net/core/sock.c index cc286bf0f1a4..f462fa055b74 100644 --- a/net/core/sock.c +++ b/net/core/sock.c @@ -2826,6 +2826,13 @@ void sk_stop_timer(struct sock *sk, struct timer_list* timer) } EXPORT_SYMBOL(sk_stop_timer); +void sk_stop_timer_sync(struct sock *sk, struct timer_list *timer) +{ + if (del_timer_sync(timer)) + __sock_put(sk); +} +EXPORT_SYMBOL(sk_stop_timer_sync); + void sock_init_data_uid(struct socket *sock, struct sock *sk, kuid_t uid) { sk_init_common(sk); -- Gitee From 6803d0847d02d1cca8b9d3ab5f6f76b6523ad3b4 Mon Sep 17 00:00:00 2001 From: Eric Dumazet Date: Thu, 6 Jun 2024 10:06:18 +0800 Subject: [PATCH 2/2] tcp: properly terminate timers for kernel sockets stable inclusion from stable-v4.19.312 commit 93f0133b9d589cc6e865f254ad9be3e9d8133f50 category: bugfix bugzilla: https://gitee.com/src-openeuler/kernel/issues/I9QG5Z CVE: CVE-2024-35910 Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=93f0133b9d589cc6e865f254ad9be3e9d8133f50 -------------------------------- [ Upstream commit 151c9c724d05d5b0dd8acd3e11cb69ef1f2dbada ] We had various syzbot reports about tcp timers firing after the corresponding netns has been dismantled. Fortunately Josef Bacik could trigger the issue more often, and could test a patch I wrote two years ago. When TCP sockets are closed, we call inet_csk_clear_xmit_timers() to 'stop' the timers. inet_csk_clear_xmit_timers() can be called from any context, including when socket lock is held. This is the reason it uses sk_stop_timer(), aka del_timer(). This means that ongoing timers might finish much later. For user sockets, this is fine because each running timer holds a reference on the socket, and the user socket holds a reference on the netns. For kernel sockets, we risk that the netns is freed before timer can complete, because kernel sockets do not hold reference on the netns. This patch adds inet_csk_clear_xmit_timers_sync() function that using sk_stop_timer_sync() to make sure all timers are terminated before the kernel socket is released. Modules using kernel sockets close them in their netns exit() handler. Also add sock_not_owned_by_me() helper to get LOCKDEP support : inet_csk_clear_xmit_timers_sync() must not be called while socket lock is held. It is very possible we can revert in the future commit 3a58f13a881e ("net: rds: acquire refcount on TCP sockets") which attempted to solve the issue in rds only. (net/smc/af_smc.c and net/mptcp/subflow.c have similar code) We probably can remove the check_net() tests from tcp_out_of_resources() and __tcp_close() in the future. Reported-by: Josef Bacik Closes: https://lore.kernel.org/netdev/20240314210740.GA2823176@perftesting/ Fixes: 26abe14379f8 ("net: Modify sk_alloc to not reference count the netns of kernel sockets.") Fixes: 8a68173691f0 ("net: sk_clone_lock() should only do get_net() if the parent is not a kernel socket") Link: https://lore.kernel.org/bpf/CANn89i+484ffqb93aQm1N-tjxxvb3WDKX0EbD7318RwRgsatjw@mail.gmail.com/ Signed-off-by: Eric Dumazet Tested-by: Josef Bacik Cc: Tetsuo Handa Link: https://lore.kernel.org/r/20240322135732.1535772-1-edumazet@google.com Signed-off-by: Jakub Kicinski Signed-off-by: Sasha Levin Signed-off-by: Liu Jian --- include/net/inet_connection_sock.h | 1 + include/net/sock.h | 7 +++++++ net/ipv4/inet_connection_sock.c | 14 ++++++++++++++ net/ipv4/tcp.c | 2 ++ 4 files changed, 24 insertions(+) diff --git a/include/net/inet_connection_sock.h b/include/net/inet_connection_sock.h index 696f96bd26ef..eba017715a0c 100644 --- a/include/net/inet_connection_sock.h +++ b/include/net/inet_connection_sock.h @@ -177,6 +177,7 @@ void inet_csk_init_xmit_timers(struct sock *sk, void (*delack_handler)(struct timer_list *), void (*keepalive_handler)(struct timer_list *)); void inet_csk_clear_xmit_timers(struct sock *sk); +void inet_csk_clear_xmit_timers_sync(struct sock *sk); static inline void inet_csk_schedule_ack(struct sock *sk) { diff --git a/include/net/sock.h b/include/net/sock.h index e6d74da86930..b1bdd70e57f0 100644 --- a/include/net/sock.h +++ b/include/net/sock.h @@ -1631,6 +1631,13 @@ static inline void sock_owned_by_me(const struct sock *sk) #endif } +static inline void sock_not_owned_by_me(const struct sock *sk) +{ +#ifdef CONFIG_LOCKDEP + WARN_ON_ONCE(lockdep_sock_is_held(sk) && debug_locks); +#endif +} + static inline bool sock_owned_by_user(const struct sock *sk) { sock_owned_by_me(sk); diff --git a/net/ipv4/inet_connection_sock.c b/net/ipv4/inet_connection_sock.c index 4c3df3b44f8e..c1f90e08761c 100644 --- a/net/ipv4/inet_connection_sock.c +++ b/net/ipv4/inet_connection_sock.c @@ -568,6 +568,20 @@ void inet_csk_clear_xmit_timers(struct sock *sk) } EXPORT_SYMBOL(inet_csk_clear_xmit_timers); +void inet_csk_clear_xmit_timers_sync(struct sock *sk) +{ + struct inet_connection_sock *icsk = inet_csk(sk); + + /* ongoing timer handlers need to acquire socket lock. */ + sock_not_owned_by_me(sk); + + icsk->icsk_pending = icsk->icsk_ack.pending = 0; + + sk_stop_timer_sync(sk, &icsk->icsk_retransmit_timer); + sk_stop_timer_sync(sk, &icsk->icsk_delack_timer); + sk_stop_timer_sync(sk, &sk->sk_timer); +} + void inet_csk_delete_keepalive_timer(struct sock *sk) { sk_stop_timer(sk, &sk->sk_timer); diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c index 4416d1c24dbb..6d3eec1a89c6 100644 --- a/net/ipv4/tcp.c +++ b/net/ipv4/tcp.c @@ -2521,6 +2521,8 @@ void tcp_close(struct sock *sk, long timeout) lock_sock(sk); __tcp_close(sk, timeout); release_sock(sk); + if (!sk->sk_net_refcnt) + inet_csk_clear_xmit_timers_sync(sk); sock_put(sk); } EXPORT_SYMBOL(tcp_close); -- Gitee