[IPSEC]: Avoid undefined shift operation when testing algorithm ID

[ Upstream commit: f398035f2dec0a6150833b0bc105057953594edb ]

The aalgos/ealgos fields are only 32 bits wide.  However, af_key tries
to test them with the expression 1 << id where id can be as large as
253.  This produces different behaviour on different architectures.

The following patch explicitly checks whether ID is greater than 31
and fails the check if that's the case.

We cannot easily extend the mask to be longer than 32 bits due to
exposure to user-space.  Besides, this whole interface is obsolete
anyway in favour of the xfrm_user interface which doesn't use this
bit mask in templates (well not within the kernel anyway).

Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Adrian Bunk <bunk@kernel.org>

diff --git a/net/key/af_key.c b/net/key/af_key.c
index 2f8cfb9c842bd045ee1344015117195587792395..82938b9b53d1b1b3850e5dd68361e74f2374e23c 100644 (file)
--- a/net/key/af_key.c
+++ b/net/key/af_key.c
@@ -2484,12 +2484,22 @@ static struct sadb_msg *pfkey_get_base_msg(struct sk_buff *skb, int *errp)
 
 static inline int aalg_tmpl_set(struct xfrm_tmpl *t, struct xfrm_algo_desc *d)
 {
-       return t->aalgos & (1 << d->desc.sadb_alg_id);
+       unsigned int id = d->desc.sadb_alg_id;
+
+       if (id >= sizeof(t->aalgos) * 8)
+               return 0;
+
+       return (t->aalgos >> id) & 1;
 }
 
 static inline int ealg_tmpl_set(struct xfrm_tmpl *t, struct xfrm_algo_desc *d)
 {
-       return t->ealgos & (1 << d->desc.sadb_alg_id);
+       unsigned int id = d->desc.sadb_alg_id;
+
+       if (id >= sizeof(t->ealgos) * 8)
+               return 0;
+
+       return (t->ealgos >> id) & 1;
 }
 
 static int count_ah_combs(struct xfrm_tmpl *t)