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 776bd93c2218..e3e96606976b 100644 --- a/net/xfrm/xfrm_state.c +++ b/net/xfrm/xfrm_state.c @@ -484,6 +484,7 @@ 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); @@ -496,6 +497,7 @@ 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) { @@ -661,7 +663,6 @@ 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