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Message-ID: <20230209053416.GA5032@ubuntu>
Date: Wed, 8 Feb 2023 21:34:16 -0800
From: Hyunwoo Kim <v4bel@...ori.io>
To: Herbert Xu <herbert@...dor.apana.org.au>
Cc: Sabrina Dubroca <sd@...asysnail.net>, steffen.klassert@...unet.com,
davem@...emloft.net, edumazet@...gle.com, kuba@...nel.org,
pabeni@...hat.com, v4bel@...ori.io, imv4bel@...il.com,
netdev@...r.kernel.org
Subject: Re: [PATCH] xfrm: Zero padding when dumping algos and encap
On Thu, Feb 09, 2023 at 07:08:57AM +0800, Herbert Xu wrote:
> On Wed, Feb 08, 2023 at 02:15:47PM +0100, Sabrina Dubroca wrote:
> >
> > Do you mean as a replacement for Hyunwoo's patch, or that both are
> > needed? pfkey_msg2xfrm_state doesn't always initialize encap_sport and
> > encap_dport (and calg->alg_key_len, but you're not using that in
> > copy_to_user_calg), so I guess you mean both patches.
>
> It's meant to be a replacement but yes we should still zero x->encap
> because that will leak out in other ways, e.g., on the wire.
>
> Hyunwoo, could you please repost your patch just for x->encap?
Can the x->encap patch do this?
I didn't add the syzbot hash as x->encap is not the flow reported by syzbot:
Subject: [PATCH] af_key: Fix heap information leak
Since x->encap of pfkey_msg2xfrm_state() is not
initialized to 0, kernel heap data can be leaked.
Fix with kzalloc() to prevent this.
Signed-off-by: Hyunwoo Kim <v4bel@...ori.io>
---
net/key/af_key.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/net/key/af_key.c b/net/key/af_key.c
index 2bdbcec781cd..a815f5ab4c49 100644
--- a/net/key/af_key.c
+++ b/net/key/af_key.c
@@ -1261,7 +1261,7 @@ static struct xfrm_state * pfkey_msg2xfrm_state(struct net *net,
const struct sadb_x_nat_t_type* n_type;
struct xfrm_encap_tmpl *natt;
- x->encap = kmalloc(sizeof(*x->encap), GFP_KERNEL);
+ x->encap = kzalloc(sizeof(*x->encap), GFP_KERNEL);
if (!x->encap) {
err = -ENOMEM;
goto out;
>
> > > +static int copy_to_user_encap(struct xfrm_encap_tmpl *ep, struct sk_buff *skb)
> > > +{
> > > + struct nlattr *nla = nla_reserve(skb, XFRMA_ALG_COMP, sizeof(*ep));
> >
> > XFRMA_ENCAP
>
> Good catch. I will repost the patch.
>
> > > + uep->encap_oa = ep->encap_oa;
> >
> > Should that be a memcpy? At least that's how xfrm_user.c usually does
> > copies of xfrm_address_t.
>
> It doesn't really matter.
>
> Thanks,
> --
> 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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