[PATCH OLK-6.6 0/2] net: xfrm: Fix CVE-2025-40215
Fix CVE-2025-40215 Sabrina Dubroca (2): xfrm: delete x->tunnel as we delete x xfrm: also call xfrm_state_delete_tunnel at destroy time for states that were never added include/net/xfrm.h | 1 - net/ipv4/ipcomp.c | 2 ++ net/ipv6/ipcomp6.c | 2 ++ net/ipv6/xfrm6_tunnel.c | 2 +- net/xfrm/xfrm_ipcomp.c | 1 - net/xfrm/xfrm_state.c | 20 +++++++++----------- 6 files changed, 14 insertions(+), 14 deletions(-) -- 2.25.1
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From: Sabrina Dubroca <sd@queasysnail.net> mainline inclusion from mainline-v6.16-rc1 commit b441cf3f8c4b8576639d20c8eb4aa32917602ecd category: bugfix bugzilla: https://atomgit.com/src-openeuler/kernel/issues/11221 CVE: CVE-2025-40215 Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?i... -------------------------------- The ipcomp fallback tunnels currently get deleted (from the various lists and hashtables) as the last user state that needed that fallback is destroyed (not deleted). If a reference to that user state still exists, the fallback state will remain on the hashtables/lists, triggering the WARN in xfrm_state_fini. Because of those remaining references, the fix in commit f75a2804da39 ("xfrm: destroy xfrm_state synchronously on net exit path") is not complete. We recently fixed one such situation in TCP due to defered freeing of skbs (commit 9b6412e6979f ("tcp: drop secpath at the same time as we currently drop dst")). This can also happen due to IP reassembly: skbs with a secpath remain on the reassembly queue until netns destruction. If we can't guarantee that the queues are flushed by the time xfrm_state_fini runs, there may still be references to a (user) xfrm_state, preventing the timely deletion of the corresponding fallback state. Instead of chasing each instance of skbs holding a secpath one by one, this patch fixes the issue directly within xfrm, by deleting the fallback state as soon as the last user state depending on it has been deleted. Destruction will still happen when the final reference is dropped. A separate lockdep class for the fallback state is required since we're going to lock x->tunnel while x is locked. Fixes: 9d4139c76905 ("netns xfrm: per-netns xfrm_state_all list") Signed-off-by: Sabrina Dubroca <sd@queasysnail.net> Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com> Conflicts: net/xfrm/xfrm_ipcomp.c net/xfrm/xfrm_state.c [commit eb2953d26971 and f531d13bdfe3 are not backport] Signed-off-by: Dong Chenchen <dongchenchen2@huawei.com> --- include/net/xfrm.h | 1 - net/ipv4/ipcomp.c | 2 ++ net/ipv6/ipcomp6.c | 2 ++ net/ipv6/xfrm6_tunnel.c | 2 +- net/xfrm/xfrm_ipcomp.c | 1 - net/xfrm/xfrm_state.c | 19 ++++++++----------- 6 files changed, 13 insertions(+), 14 deletions(-) diff --git a/include/net/xfrm.h b/include/net/xfrm.h index 09a60199c502..65ee0561ecaa 100644 --- a/include/net/xfrm.h +++ b/include/net/xfrm.h @@ -419,7 +419,6 @@ int xfrm_input_register_afinfo(const struct xfrm_input_afinfo *afinfo); int xfrm_input_unregister_afinfo(const struct xfrm_input_afinfo *afinfo); void xfrm_flush_gc(void); -void xfrm_state_delete_tunnel(struct xfrm_state *x); struct xfrm_type { struct module *owner; diff --git a/net/ipv4/ipcomp.c b/net/ipv4/ipcomp.c index 5a4fb2539b08..9a45aed508d1 100644 --- a/net/ipv4/ipcomp.c +++ b/net/ipv4/ipcomp.c @@ -54,6 +54,7 @@ static int ipcomp4_err(struct sk_buff *skb, u32 info) } /* We always hold one tunnel user reference to indicate a tunnel */ +static struct lock_class_key xfrm_state_lock_key; static struct xfrm_state *ipcomp_tunnel_create(struct xfrm_state *x) { struct net *net = xs_net(x); @@ -62,6 +63,7 @@ static struct xfrm_state *ipcomp_tunnel_create(struct xfrm_state *x) t = xfrm_state_alloc(net); if (!t) goto out; + lockdep_set_class(&t->lock, &xfrm_state_lock_key); t->id.proto = IPPROTO_IPIP; t->id.spi = x->props.saddr.a4; diff --git a/net/ipv6/ipcomp6.c b/net/ipv6/ipcomp6.c index 72d4858dec18..8607569de34f 100644 --- a/net/ipv6/ipcomp6.c +++ b/net/ipv6/ipcomp6.c @@ -71,6 +71,7 @@ static int ipcomp6_err(struct sk_buff *skb, struct inet6_skb_parm *opt, return 0; } +static struct lock_class_key xfrm_state_lock_key; static struct xfrm_state *ipcomp6_tunnel_create(struct xfrm_state *x) { struct net *net = xs_net(x); @@ -79,6 +80,7 @@ static struct xfrm_state *ipcomp6_tunnel_create(struct xfrm_state *x) t = xfrm_state_alloc(net); if (!t) goto out; + lockdep_set_class(&t->lock, &xfrm_state_lock_key); t->id.proto = IPPROTO_IPV6; t->id.spi = xfrm6_tunnel_alloc_spi(net, (xfrm_address_t *)&x->props.saddr); diff --git a/net/ipv6/xfrm6_tunnel.c b/net/ipv6/xfrm6_tunnel.c index 1323f2f6928e..1702b4de1c1e 100644 --- a/net/ipv6/xfrm6_tunnel.c +++ b/net/ipv6/xfrm6_tunnel.c @@ -334,8 +334,8 @@ static void __net_exit xfrm6_tunnel_net_exit(struct net *net) struct xfrm6_tunnel_net *xfrm6_tn = xfrm6_tunnel_pernet(net); unsigned int i; - xfrm_flush_gc(); xfrm_state_flush(net, 0, false, true); + xfrm_flush_gc(); for (i = 0; i < XFRM6_TUNNEL_SPI_BYADDR_HSIZE; i++) WARN_ON_ONCE(!hlist_empty(&xfrm6_tn->spi_byaddr[i])); diff --git a/net/xfrm/xfrm_ipcomp.c b/net/xfrm/xfrm_ipcomp.c index 9c0fa0e1786a..f2e70e918f11 100644 --- a/net/xfrm/xfrm_ipcomp.c +++ b/net/xfrm/xfrm_ipcomp.c @@ -315,7 +315,6 @@ void ipcomp_destroy(struct xfrm_state *x) struct ipcomp_data *ipcd = x->data; if (!ipcd) return; - xfrm_state_delete_tunnel(x); mutex_lock(&ipcomp_resource_mutex); ipcomp_free_data(ipcd); mutex_unlock(&ipcomp_resource_mutex); diff --git a/net/xfrm/xfrm_state.c b/net/xfrm/xfrm_state.c index 4efbc0b22378..dc1c765fa601 100644 --- a/net/xfrm/xfrm_state.c +++ b/net/xfrm/xfrm_state.c @@ -709,6 +709,7 @@ void __xfrm_state_destroy(struct xfrm_state *x, bool sync) } EXPORT_SYMBOL(__xfrm_state_destroy); +static void xfrm_state_delete_tunnel(struct xfrm_state *x); int __xfrm_state_delete(struct xfrm_state *x) { struct net *net = xs_net(x); @@ -729,6 +730,8 @@ int __xfrm_state_delete(struct xfrm_state *x) xfrm_dev_state_delete(x); + xfrm_state_delete_tunnel(x); + /* All xfrm_state objects are created by xfrm_state_alloc. * The xfrm_state_alloc call gives a reference, and that * is what we are dropping here. @@ -832,10 +835,7 @@ int xfrm_state_flush(struct net *net, u8 proto, bool task_valid, bool sync) err = xfrm_state_delete(x); xfrm_audit_state_delete(x, err ? 0 : 1, task_valid); - if (sync) - xfrm_state_put_sync(x); - else - xfrm_state_put(x); + xfrm_state_put(x); if (!err) cnt++; @@ -2789,20 +2789,17 @@ void xfrm_flush_gc(void) } EXPORT_SYMBOL(xfrm_flush_gc); -/* Temporarily located here until net/xfrm/xfrm_tunnel.c is created */ -void xfrm_state_delete_tunnel(struct xfrm_state *x) +static void xfrm_state_delete_tunnel(struct xfrm_state *x) { if (x->tunnel) { struct xfrm_state *t = x->tunnel; - if (atomic_read(&t->tunnel_users) == 2) + if (atomic_dec_return(&t->tunnel_users) == 1) xfrm_state_delete(t); - atomic_dec(&t->tunnel_users); - xfrm_state_put_sync(t); + xfrm_state_put(t); x->tunnel = NULL; } } -EXPORT_SYMBOL(xfrm_state_delete_tunnel); u32 xfrm_state_mtu(struct xfrm_state *x, int mtu) { @@ -2980,8 +2977,8 @@ void xfrm_state_fini(struct net *net) unsigned int sz; flush_work(&net->xfrm.state_hash_work); - flush_work(&xfrm_state_gc_work); xfrm_state_flush(net, 0, false, true); + flush_work(&xfrm_state_gc_work); WARN_ON(!list_empty(&net->xfrm.state_all)); -- 2.25.1
From: Sabrina Dubroca <sd@queasysnail.net> mainline inclusion from mainline-v6.18-rc7 commit 10deb69864840ccf96b00ac2ab3a2055c0c04721 category: bugfix bugzilla: https://atomgit.com/src-openeuler/kernel/issues/11221 CVE: CVE-2025-40215 Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?i... -------------------------------- In commit b441cf3f8c4b ("xfrm: delete x->tunnel as we delete x"), I missed the case where state creation fails between full initialization (->init_state has been called) and being inserted on the lists. In this situation, ->init_state has been called, so for IPcomp tunnels, the fallback tunnel has been created and added onto the lists, but the user state never gets added, because we fail before that. The user state doesn't go through __xfrm_state_delete, so we don't call xfrm_state_delete_tunnel for those states, and we end up leaking the FB tunnel. There are several codepaths affected by this: the add/update paths, in both net/key and xfrm, and the migrate code (xfrm_migrate, xfrm_state_migrate). A "proper" rollback of the init_state work would probably be doable in the add/update code, but for migrate it gets more complicated as multiple states may be involved. At some point, the new (not-inserted) state will be destroyed, so call xfrm_state_delete_tunnel during xfrm_state_gc_destroy. Most states will have their fallback tunnel cleaned up during __xfrm_state_delete, which solves the issue that b441cf3f8c4b (and other patches before it) aimed at. All states (including FB tunnels) will be removed from the lists once xfrm_state_fini has called flush_work(&xfrm_state_gc_work). Reported-by: syzbot+999eb23467f83f9bf9bf@syzkaller.appspotmail.com Closes: https://syzkaller.appspot.com/bug?extid=999eb23467f83f9bf9bf Fixes: b441cf3f8c4b ("xfrm: delete x->tunnel as we delete x") Signed-off-by: Sabrina Dubroca <sd@queasysnail.net> Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com> Conflicts: net/xfrm/xfrm_state.c [commit 2a198bbec691 is not backport] Signed-off-by: Dong Chenchen <dongchenchen2@huawei.com> --- net/xfrm/xfrm_state.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/net/xfrm/xfrm_state.c b/net/xfrm/xfrm_state.c index dc1c765fa601..6d94cb0da6e3 100644 --- a/net/xfrm/xfrm_state.c +++ b/net/xfrm/xfrm_state.c @@ -529,6 +529,7 @@ void xfrm_state_free(struct xfrm_state *x) } EXPORT_SYMBOL(xfrm_state_free); +static void xfrm_state_delete_tunnel(struct xfrm_state *x); static void ___xfrm_state_destroy(struct xfrm_state *x) { hrtimer_cancel(&x->mtimer); @@ -541,6 +542,7 @@ static void ___xfrm_state_destroy(struct xfrm_state *x) kfree(x->coaddr); kfree(x->replay_esn); kfree(x->preplay_esn); + xfrm_state_delete_tunnel(x); if (x->type_offload) xfrm_put_type_offload(x->type_offload); if (x->type) { @@ -709,7 +711,6 @@ void __xfrm_state_destroy(struct xfrm_state *x, bool sync) } EXPORT_SYMBOL(__xfrm_state_destroy); -static void xfrm_state_delete_tunnel(struct xfrm_state *x); int __xfrm_state_delete(struct xfrm_state *x) { struct net *net = xs_net(x); -- 2.25.1
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