From: Sabrina Dubroca <sd@queasysnail.net> stable inclusion from stable-v6.6.93 commit b58a295d10065960bcb9d60cb8ca6ead9837cd27 category: bugfix bugzilla: https://gitee.com/src-openeuler/kernel/issues/ICJTCO CVE: CVE-2025-38097 Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=... -------------------------------- [ Upstream commit 028363685bd0b7a19b4a820f82dd905b1dc83999 ] The current scheme for caching the encap socket can lead to reference leaks when we try to delete the netns. The reference chain is: xfrm_state -> enacp_sk -> netns Since the encap socket is a userspace socket, it holds a reference on the netns. If we delete the espintcp state (through flush or individual delete) before removing the netns, the reference on the socket is dropped and the netns is correctly deleted. Otherwise, the netns may not be reachable anymore (if all processes within the ns have terminated), so we cannot delete the xfrm state to drop its reference on the socket. This patch results in a small (~2% in my tests) performance regression. A GC-type mechanism could be added for the socket cache, to clear references if the state hasn't been used "recently", but it's a lot more complex than just not caching the socket. Fixes: e27cca96cd68 ("xfrm: add espintcp (RFC 8229)") Signed-off-by: Sabrina Dubroca <sd@queasysnail.net> Reviewed-by: Simon Horman <horms@kernel.org> Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com> Signed-off-by: Sasha Levin <sashal@kernel.org> Signed-off-by: Dong Chenchen <dongchenchen2@huawei.com> --- include/net/xfrm.h | 1 - net/ipv4/esp4.c | 49 ++++--------------------------------------- net/ipv6/esp6.c | 49 ++++--------------------------------------- net/xfrm/xfrm_state.c | 3 --- 4 files changed, 8 insertions(+), 94 deletions(-) diff --git a/include/net/xfrm.h b/include/net/xfrm.h index 09a60199c502..0b8a67f85d70 100644 --- a/include/net/xfrm.h +++ b/include/net/xfrm.h @@ -227,7 +227,6 @@ struct xfrm_state { /* Data for encapsulator */ struct xfrm_encap_tmpl *encap; - struct sock __rcu *encap_sk; /* Data for care-of address */ xfrm_address_t *coaddr; diff --git a/net/ipv4/esp4.c b/net/ipv4/esp4.c index ed5f37c6d9ba..2caf6a2a819b 100644 --- a/net/ipv4/esp4.c +++ b/net/ipv4/esp4.c @@ -118,47 +118,16 @@ static void esp_ssg_unref(struct xfrm_state *x, void *tmp, struct sk_buff *skb) } #ifdef CONFIG_INET_ESPINTCP -struct esp_tcp_sk { - struct sock *sk; - struct rcu_head rcu; -}; - -static void esp_free_tcp_sk(struct rcu_head *head) -{ - struct esp_tcp_sk *esk = container_of(head, struct esp_tcp_sk, rcu); - - sock_put(esk->sk); - kfree(esk); -} - static struct sock *esp_find_tcp_sk(struct xfrm_state *x) { struct xfrm_encap_tmpl *encap = x->encap; struct net *net = xs_net(x); - struct esp_tcp_sk *esk; __be16 sport, dport; - struct sock *nsk; struct sock *sk; - sk = rcu_dereference(x->encap_sk); - if (sk && sk->sk_state == TCP_ESTABLISHED) - return sk; - spin_lock_bh(&x->lock); sport = encap->encap_sport; dport = encap->encap_dport; - nsk = rcu_dereference_protected(x->encap_sk, - lockdep_is_held(&x->lock)); - if (sk && sk == nsk) { - esk = kmalloc(sizeof(*esk), GFP_ATOMIC); - if (!esk) { - spin_unlock_bh(&x->lock); - return ERR_PTR(-ENOMEM); - } - RCU_INIT_POINTER(x->encap_sk, NULL); - esk->sk = sk; - call_rcu(&esk->rcu, esp_free_tcp_sk); - } spin_unlock_bh(&x->lock); sk = inet_lookup_established(net, net->ipv4.tcp_death_row.hashinfo, x->id.daddr.a4, @@ -171,20 +140,6 @@ static struct sock *esp_find_tcp_sk(struct xfrm_state *x) return ERR_PTR(-EINVAL); } - spin_lock_bh(&x->lock); - nsk = rcu_dereference_protected(x->encap_sk, - lockdep_is_held(&x->lock)); - if (encap->encap_sport != sport || - encap->encap_dport != dport) { - sock_put(sk); - sk = nsk ?: ERR_PTR(-EREMCHG); - } else if (sk == nsk) { - sock_put(sk); - } else { - rcu_assign_pointer(x->encap_sk, sk); - } - spin_unlock_bh(&x->lock); - return sk; } @@ -209,6 +164,8 @@ static int esp_output_tcp_finish(struct xfrm_state *x, struct sk_buff *skb) err = espintcp_push_skb(sk, skb); bh_unlock_sock(sk); + sock_put(sk); + out: rcu_read_unlock(); return err; @@ -393,6 +350,8 @@ static struct ip_esp_hdr *esp_output_tcp_encap(struct xfrm_state *x, if (IS_ERR(sk)) return ERR_CAST(sk); + sock_put(sk); + *lenp = htons(len); esph = (struct ip_esp_hdr *)(lenp + 1); diff --git a/net/ipv6/esp6.c b/net/ipv6/esp6.c index 43a9966e2064..2caaab61b996 100644 --- a/net/ipv6/esp6.c +++ b/net/ipv6/esp6.c @@ -135,47 +135,16 @@ static void esp_ssg_unref(struct xfrm_state *x, void *tmp, struct sk_buff *skb) } #ifdef CONFIG_INET6_ESPINTCP -struct esp_tcp_sk { - struct sock *sk; - struct rcu_head rcu; -}; - -static void esp_free_tcp_sk(struct rcu_head *head) -{ - struct esp_tcp_sk *esk = container_of(head, struct esp_tcp_sk, rcu); - - sock_put(esk->sk); - kfree(esk); -} - static struct sock *esp6_find_tcp_sk(struct xfrm_state *x) { struct xfrm_encap_tmpl *encap = x->encap; struct net *net = xs_net(x); - struct esp_tcp_sk *esk; __be16 sport, dport; - struct sock *nsk; struct sock *sk; - sk = rcu_dereference(x->encap_sk); - if (sk && sk->sk_state == TCP_ESTABLISHED) - return sk; - spin_lock_bh(&x->lock); sport = encap->encap_sport; dport = encap->encap_dport; - nsk = rcu_dereference_protected(x->encap_sk, - lockdep_is_held(&x->lock)); - if (sk && sk == nsk) { - esk = kmalloc(sizeof(*esk), GFP_ATOMIC); - if (!esk) { - spin_unlock_bh(&x->lock); - return ERR_PTR(-ENOMEM); - } - RCU_INIT_POINTER(x->encap_sk, NULL); - esk->sk = sk; - call_rcu(&esk->rcu, esp_free_tcp_sk); - } spin_unlock_bh(&x->lock); sk = __inet6_lookup_established(net, net->ipv4.tcp_death_row.hashinfo, &x->id.daddr.in6, @@ -188,20 +157,6 @@ static struct sock *esp6_find_tcp_sk(struct xfrm_state *x) return ERR_PTR(-EINVAL); } - spin_lock_bh(&x->lock); - nsk = rcu_dereference_protected(x->encap_sk, - lockdep_is_held(&x->lock)); - if (encap->encap_sport != sport || - encap->encap_dport != dport) { - sock_put(sk); - sk = nsk ?: ERR_PTR(-EREMCHG); - } else if (sk == nsk) { - sock_put(sk); - } else { - rcu_assign_pointer(x->encap_sk, sk); - } - spin_unlock_bh(&x->lock); - return sk; } @@ -226,6 +181,8 @@ static int esp_output_tcp_finish(struct xfrm_state *x, struct sk_buff *skb) err = espintcp_push_skb(sk, skb); bh_unlock_sock(sk); + sock_put(sk); + out: rcu_read_unlock(); return err; @@ -429,6 +386,8 @@ static struct ip_esp_hdr *esp6_output_tcp_encap(struct xfrm_state *x, if (IS_ERR(sk)) return ERR_CAST(sk); + sock_put(sk); + *lenp = htons(len); esph = (struct ip_esp_hdr *)(lenp + 1); diff --git a/net/xfrm/xfrm_state.c b/net/xfrm/xfrm_state.c index 21b082899b9d..2c870a36842c 100644 --- a/net/xfrm/xfrm_state.c +++ b/net/xfrm/xfrm_state.c @@ -727,9 +727,6 @@ int __xfrm_state_delete(struct xfrm_state *x) net->xfrm.state_num--; spin_unlock(&net->xfrm.xfrm_state_lock); - if (x->encap_sk) - sock_put(rcu_dereference_raw(x->encap_sk)); - xfrm_dev_state_delete(x); /* All xfrm_state objects are created by xfrm_state_alloc. -- 2.25.1