Commit 257a4b01 authored Dec 26, 2017 by Herbert Xu Committed by Steffen Klassert Dec 30, 2017

xfrm: Forbid state updates from changing encap type



Currently we allow state updates to competely replace the contents
of x->encap.  This is bad because on the user side ESP only sets up
header lengths depending on encap_type once when the state is first
created.  This could result in the header lengths getting out of
sync with the actual state configuration.

In practice key managers will never do a state update to change the
encapsulation type.  Only the port numbers need to be changed as the
peer NAT entry is updated.

Therefore this patch adds a check in xfrm_state_update to forbid
any changes to the encap_type.

Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>

parent 2758b3e3

net/xfrm/xfrm_state.c

+7 −1

Original line number	Diff line number	Diff line
		@@ -1534,8 +1534,12 @@ out:
		err = -EINVAL;
		spin_lock_bh(&x1->lock);
		if (likely(x1->km.state == XFRM_STATE_VALID)) {
		if (x->encap && x1->encap)
		if (x->encap && x1->encap &&
		x->encap->encap_type == x1->encap->encap_type)
		memcpy(x1->encap, x->encap, sizeof(*x1->encap));
		else if (x->encap \|\| x1->encap)
		goto fail;

		if (x->coaddr && x1->coaddr) {
		memcpy(x1->coaddr, x->coaddr, sizeof(*x1->coaddr));
		}
		@@ -1552,6 +1556,8 @@ out:
		x->km.state = XFRM_STATE_DEAD;
		__xfrm_state_put(x);
		}

		fail:
		spin_unlock_bh(&x1->lock);

		xfrm_state_put(x1);

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