xfrm: also call xfrm_state_delete_tunnel at destroy time for states that were never added

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[ Upstream commit 10deb69864 ]

In commit b441cf3f8c ("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 b441cf3f8c (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: b441cf3f8c ("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>
Signed-off-by: Sasha Levin <sashal@kernel.org>

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This commit is contained in:

Sabrina Dubroca 2025-12-04 17:43:27 -05:00 • committed by Greg Kroah-Hartman

parent 13b32a7e54

commit f7d879c19d

1 changed files with 2 additions and 1 deletions

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net/xfrm/xfrm_state.c

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