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Message-ID: <Y+RH4Fv8yj0g535y@gondor.apana.org.au>
Date: Thu, 9 Feb 2023 09:09:52 +0800
From: Herbert Xu <herbert@...dor.apana.org.au>
To: Hyunwoo Kim <v4bel@...ori.io>
Cc: steffen.klassert@...unet.com, davem@...emloft.net,
edumazet@...gle.com, kuba@...nel.org, pabeni@...hat.com,
imv4bel@...il.com, netdev@...r.kernel.org,
Sabrina Dubroca <sd@...asysnail.net>
Subject: [v2 PATCH] xfrm: Zero padding when dumping algos and encap
v2 fixes the mistaken type of XFRMA_ALG_COMP for x->encap.
---8<---
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@...kaller.appspotmail.com
Reported-by: Hyunwoo Kim <v4bel@...ori.io>
Signed-off-by: Herbert Xu <herbert@...dor.apana.org.au>
diff --git a/net/xfrm/xfrm_user.c b/net/xfrm/xfrm_user.c
index cf5172d4ce68..103af2b3e986 100644
--- a/net/xfrm/xfrm_user.c
+++ b/net/xfrm/xfrm_user.c
@@ -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;
}
--
Email: Herbert Xu <herbert@...dor.apana.org.au>
Home Page: http://gondor.apana.org.au/~herbert/
PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt
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