Commit 10deb698 authored by Sabrina Dubroca's avatar Sabrina Dubroca Committed by Steffen Klassert
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xfrm: also call xfrm_state_delete_tunnel at destroy time for states that were never added 



In commit b441cf3f ("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 b441cf3f (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: default avatar <syzbot+999eb23467f83f9bf9bf@syzkaller.appspotmail.com>
Closes: https://syzkaller.appspot.com/bug?extid=999eb23467f83f9bf9bf


Fixes: b441cf3f ("xfrm: delete x->tunnel as we delete x")
Signed-off-by: default avatarSabrina Dubroca <sd@queasysnail.net>
Signed-off-by: default avatarSteffen Klassert <steffen.klassert@secunet.com>
parent 8d2a2a49

net/xfrm/xfrm_state.c

+2 −1
Original line number Diff line number Diff line
@@ -592,6 +592,7 @@ 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_gc_destroy(struct xfrm_state *x)

{

	if (x->mode_cbs && x->mode_cbs->destroy_state)
@@ -607,6 +608,7 @@ static void xfrm_state_gc_destroy(struct xfrm_state *x) 
	kfree(x->replay_esn);

	kfree(x->preplay_esn);

	xfrm_unset_type_offload(x);

	xfrm_state_delete_tunnel(x);

	if (x->type) {

		x->type->destructor(x);

		xfrm_put_type(x->type);
@@ -806,7 +808,6 @@ void __xfrm_state_destroy(struct xfrm_state *x) 
}

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);