Commit 8222d591 authored by Herbert Xu's avatar Herbert Xu Committed by Steffen Klassert
Browse files

xfrm: Zero padding when dumping algos and encap 



When copying data to user-space we should ensure that only valid
data is copied over.  Padding in structures may be filled with
random (possibly sensitve) data and should never be given directly
to user-space.

This patch fixes the copying of xfrm algorithms and the encap
template in xfrm_user so that padding is zeroed.

Reported-by: default avatar <syzbot+fa5414772d5c445dac3c@syzkaller.appspotmail.com>
Reported-by: default avatarHyunwoo Kim <v4bel@theori.io>
Signed-off-by: default avatarHerbert Xu <herbert@gondor.apana.org.au>
Reviewed-by: default avatarSabrina Dubroca <sd@queasysnail.net>
Signed-off-by: default avatarSteffen Klassert <steffen.klassert@secunet.com>
parent 2038cc59

net/xfrm/xfrm_user.c

+41 −4
Original line number Diff line number Diff line
@@ -1012,7 +1012,9 @@ static int copy_to_user_aead(struct xfrm_algo_aead *aead, struct sk_buff *skb) 
		return -EMSGSIZE;



	ap = nla_data(nla);

	memcpy(ap, aead, sizeof(*aead));

	strscpy_pad(ap->alg_name, aead->alg_name, sizeof(ap->alg_name));

	ap->alg_key_len = aead->alg_key_len;

	ap->alg_icv_len = aead->alg_icv_len;



	if (redact_secret && aead->alg_key_len)

		memset(ap->alg_key, 0, (aead->alg_key_len + 7) / 8);
@@ -1032,7 +1034,8 @@ static int copy_to_user_ealg(struct xfrm_algo *ealg, struct sk_buff *skb) 
		return -EMSGSIZE;



	ap = nla_data(nla);

	memcpy(ap, ealg, sizeof(*ealg));

	strscpy_pad(ap->alg_name, ealg->alg_name, sizeof(ap->alg_name));

	ap->alg_key_len = ealg->alg_key_len;



	if (redact_secret && ealg->alg_key_len)

		memset(ap->alg_key, 0, (ealg->alg_key_len + 7) / 8);
@@ -1043,6 +1046,40 @@ static int copy_to_user_ealg(struct xfrm_algo *ealg, struct sk_buff *skb) 
	return 0;

}



static int copy_to_user_calg(struct xfrm_algo *calg, struct sk_buff *skb)

{

	struct nlattr *nla = nla_reserve(skb, XFRMA_ALG_COMP, sizeof(*calg));

	struct xfrm_algo *ap;



	if (!nla)

		return -EMSGSIZE;



	ap = nla_data(nla);

	strscpy_pad(ap->alg_name, calg->alg_name, sizeof(ap->alg_name));

	ap->alg_key_len = 0;



	return 0;

}



static int copy_to_user_encap(struct xfrm_encap_tmpl *ep, struct sk_buff *skb)

{

	struct nlattr *nla = nla_reserve(skb, XFRMA_ENCAP, sizeof(*ep));

	struct xfrm_encap_tmpl *uep;



	if (!nla)

		return -EMSGSIZE;



	uep = nla_data(nla);

	memset(uep, 0, sizeof(*uep));



	uep->encap_type = ep->encap_type;

	uep->encap_sport = ep->encap_sport;

	uep->encap_dport = ep->encap_dport;

	uep->encap_oa = ep->encap_oa;



	return 0;

}



static int xfrm_smark_put(struct sk_buff *skb, struct xfrm_mark *m)

{

	int ret = 0;
@@ -1098,12 +1135,12 @@ static int copy_to_user_state_extra(struct xfrm_state *x, 
			goto out;

	}

	if (x->calg) {

		ret = nla_put(skb, XFRMA_ALG_COMP, sizeof(*(x->calg)), x->calg);

		ret = copy_to_user_calg(x->calg, skb);

		if (ret)

			goto out;

	}

	if (x->encap) {

		ret = nla_put(skb, XFRMA_ENCAP, sizeof(*x->encap), x->encap);

		ret = copy_to_user_encap(x->encap, skb);

		if (ret)

			goto out;

	}