xfrm: Fix memory leak of aead algorithm name

commit b5884793 upstream.

commit 1a6509d9 ("[IPSEC]: Add support for combined mode algorithms")
introduced aead. The function attach_aead kmemdup()s the algorithm
name during xfrm_state_construct().
However this memory is never freed.
Implementation has since been slightly modified in
commit ee5c2317 ("xfrm: Clone states properly on migration")
without resolving this leak.
This patch adds a kfree() call for the aead algorithm name.

Fixes: 1a6509d9 ("[IPSEC]: Add support for combined mode algorithms")
Signed-off-by: Ilan Tayari <ilant@mellanox.com>
Acked-by: Rami Rosen <roszenrami@gmail.com>
Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>

net/xfrm/xfrm_state.c

@@ -339,6 +339,7 @@ static void xfrm_state_gc_destroy(struct xfrm_state *x)
 {
 	tasklet_hrtimer_cancel(&x->mtimer);
 	del_timer_sync(&x->rtimer);
+	kfree(x->aead);
 	kfree(x->aalg);
 	kfree(x->ealg);
 	kfree(x->calg);