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: syzbot+fa5414772d5c445dac3c@syzkaller.appspotmail.com Reported-by: Hyunwoo Kim <v4bel@theori.io> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au> Reviewed-by: Sabrina Dubroca <sd@queasysnail.net> Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>
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@ -1012,7 +1012,9 @@ static int copy_to_user_aead(struct xfrm_algo_aead *aead, struct sk_buff *skb)
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return -EMSGSIZE;
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ap = nla_data(nla);
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memcpy(ap, aead, sizeof(*aead));
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strscpy_pad(ap->alg_name, aead->alg_name, sizeof(ap->alg_name));
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ap->alg_key_len = aead->alg_key_len;
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ap->alg_icv_len = aead->alg_icv_len;
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if (redact_secret && aead->alg_key_len)
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memset(ap->alg_key, 0, (aead->alg_key_len + 7) / 8);
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@ -1032,7 +1034,8 @@ static int copy_to_user_ealg(struct xfrm_algo *ealg, struct sk_buff *skb)
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return -EMSGSIZE;
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ap = nla_data(nla);
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memcpy(ap, ealg, sizeof(*ealg));
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strscpy_pad(ap->alg_name, ealg->alg_name, sizeof(ap->alg_name));
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ap->alg_key_len = ealg->alg_key_len;
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if (redact_secret && ealg->alg_key_len)
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memset(ap->alg_key, 0, (ealg->alg_key_len + 7) / 8);
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@ -1043,6 +1046,40 @@ static int copy_to_user_ealg(struct xfrm_algo *ealg, struct sk_buff *skb)
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return 0;
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}
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static int copy_to_user_calg(struct xfrm_algo *calg, struct sk_buff *skb)
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{
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struct nlattr *nla = nla_reserve(skb, XFRMA_ALG_COMP, sizeof(*calg));
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struct xfrm_algo *ap;
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if (!nla)
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return -EMSGSIZE;
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ap = nla_data(nla);
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strscpy_pad(ap->alg_name, calg->alg_name, sizeof(ap->alg_name));
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ap->alg_key_len = 0;
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return 0;
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}
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static int copy_to_user_encap(struct xfrm_encap_tmpl *ep, struct sk_buff *skb)
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{
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struct nlattr *nla = nla_reserve(skb, XFRMA_ENCAP, sizeof(*ep));
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struct xfrm_encap_tmpl *uep;
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if (!nla)
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return -EMSGSIZE;
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uep = nla_data(nla);
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memset(uep, 0, sizeof(*uep));
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uep->encap_type = ep->encap_type;
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uep->encap_sport = ep->encap_sport;
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uep->encap_dport = ep->encap_dport;
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uep->encap_oa = ep->encap_oa;
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return 0;
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}
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static int xfrm_smark_put(struct sk_buff *skb, struct xfrm_mark *m)
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{
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int ret = 0;
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@ -1098,12 +1135,12 @@ static int copy_to_user_state_extra(struct xfrm_state *x,
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goto out;
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}
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if (x->calg) {
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ret = nla_put(skb, XFRMA_ALG_COMP, sizeof(*(x->calg)), x->calg);
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ret = copy_to_user_calg(x->calg, skb);
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if (ret)
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goto out;
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}
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if (x->encap) {
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ret = nla_put(skb, XFRMA_ENCAP, sizeof(*x->encap), x->encap);
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ret = copy_to_user_encap(x->encap, skb);
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if (ret)
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goto out;
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}
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