Code: static int copy_to_user_auth(struct xfrm_algo_auth *auth, struct sk_buff *skb)
{
	struct xfrm_algo *algo;
	struct nlattr *nla;

	nla = nla_reserve(skb, XFRMA_ALG_AUTH,
			  sizeof(*algo) + (auth->alg_key_len + 7) / 8);
	if (!nla)
 		return -EMSGSIZE;
 
 	algo = nla_data(nla);
	strcpy(algo->alg_name, auth->alg_name);
 	memcpy(algo->alg_key, auth->alg_key, (auth->alg_key_len + 7) / 8);
 	algo->alg_key_len = auth->alg_key_len;
 
	return 0;
}

Commit Message: xfrm_user: fix info leak in copy_to_user_auth()

copy_to_user_auth() fails to initialize the remainder of alg_name and
therefore discloses up to 54 bytes of heap memory via netlink to
userland.

Use strncpy() instead of strcpy() to fill the trailing bytes of alg_name
with null bytes.

Signed-off-by: Mathias Krause <minipli@googlemail.com>
Acked-by: Steffen Klassert <steffen.klassert@secunet.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
CWE ID: CWE-200
static int copy_to_user_auth(struct xfrm_algo_auth *auth, struct sk_buff *skb)
{
	struct xfrm_algo *algo;
	struct nlattr *nla;

	nla = nla_reserve(skb, XFRMA_ALG_AUTH,
			  sizeof(*algo) + (auth->alg_key_len + 7) / 8);
	if (!nla)
 		return -EMSGSIZE;
 
 	algo = nla_data(nla);
	strncpy(algo->alg_name, auth->alg_name, sizeof(algo->alg_name));
 	memcpy(algo->alg_key, auth->alg_key, (auth->alg_key_len + 7) / 8);
 	algo->alg_key_len = auth->alg_key_len;
 
	return 0;
}
