From: Herbert Xu herbert@gondor.apana.org.au
[ Upstream commit 8222d5910dae08213b6d9d4bc9a7f8502855e624 ]
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 Signed-off-by: Sasha Levin sashal@kernel.org --- net/xfrm/xfrm_user.c | 45 ++++++++++++++++++++++++++++++++++++++++---- 1 file changed, 41 insertions(+), 4 deletions(-)
diff --git a/net/xfrm/xfrm_user.c b/net/xfrm/xfrm_user.c index 5fba82757ce5e..eb0952dbf4236 100644 --- a/net/xfrm/xfrm_user.c +++ b/net/xfrm/xfrm_user.c @@ -906,7 +906,9 @@ 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); @@ -926,7 +928,8 @@ 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); @@ -937,6 +940,40 @@ 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; @@ -992,12 +1029,12 @@ 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; }