2021-04-04 17:54:47

by Ilya Maximets

Subject: [PATCH net] openvswitch: fix send of uninitialized stack memory in ct limit reply

'struct ovs_zone_limit' has more members than initialized in
ovs_ct_limit_get_default_limit(). The rest of the memory is a random
kernel stack content that ends up being sent to userspace.

Fix that by using designated initializer that will clear all
non-specified fields.

Fixes: 11efd5cb04a1 ("openvswitch: Support conntrack zone limit")
Signed-off-by: Ilya Maximets <[email protected]>
---
net/openvswitch/conntrack.c | 8 ++++----
1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/net/openvswitch/conntrack.c b/net/openvswitch/conntrack.c
index c29b0ef1fc27..cadb6a29b285 100644
--- a/net/openvswitch/conntrack.c
+++ b/net/openvswitch/conntrack.c
@@ -2032,10 +2032,10 @@ static int ovs_ct_limit_del_zone_limit(struct nlattr *nla_zone_limit,
static int ovs_ct_limit_get_default_limit(struct ovs_ct_limit_info *info,
struct sk_buff *reply)
{
- struct ovs_zone_limit zone_limit;
-
- zone_limit.zone_id = OVS_ZONE_LIMIT_DEFAULT_ZONE;
- zone_limit.limit = info->default_limit;
+ struct ovs_zone_limit zone_limit = {
+ .zone_id = OVS_ZONE_LIMIT_DEFAULT_ZONE,
+ .limit = info->default_limit,
+ };

return nla_put_nohdr(reply, sizeof(zone_limit), &zone_limit);
}
--
2.26.2

2021-04-04 18:06:56

by Ilya Maximets

Subject: Re: [PATCH net] openvswitch: fix send of uninitialized stack memory in ct limit reply

CC: ovs-dev

On 4/4/21 7:50 PM, Ilya Maximets wrote:
> 'struct ovs_zone_limit' has more members than initialized in
> ovs_ct_limit_get_default_limit(). The rest of the memory is a random
> kernel stack content that ends up being sent to userspace.
>
> Fix that by using designated initializer that will clear all
> non-specified fields.
>
> Fixes: 11efd5cb04a1 ("openvswitch: Support conntrack zone limit")
> Signed-off-by: Ilya Maximets <[email protected]>
> ---
> net/openvswitch/conntrack.c | 8 ++++----
> 1 file changed, 4 insertions(+), 4 deletions(-)
>
> diff --git a/net/openvswitch/conntrack.c b/net/openvswitch/conntrack.c
> index c29b0ef1fc27..cadb6a29b285 100644
> --- a/net/openvswitch/conntrack.c
> +++ b/net/openvswitch/conntrack.c
> @@ -2032,10 +2032,10 @@ static int ovs_ct_limit_del_zone_limit(struct nlattr *nla_zone_limit,
> static int ovs_ct_limit_get_default_limit(struct ovs_ct_limit_info *info,
> struct sk_buff *reply)
> {
> - struct ovs_zone_limit zone_limit;
> -
> - zone_limit.zone_id = OVS_ZONE_LIMIT_DEFAULT_ZONE;
> - zone_limit.limit = info->default_limit;
> + struct ovs_zone_limit zone_limit = {
> + .zone_id = OVS_ZONE_LIMIT_DEFAULT_ZONE,
> + .limit = info->default_limit,
> + };
>
> return nla_put_nohdr(reply, sizeof(zone_limit), &zone_limit);
> }
>

2021-04-05 03:39:02

by Tonghao Zhang

Subject: Re: [ovs-dev] [PATCH net] openvswitch: fix send of uninitialized stack memory in ct limit reply

On Mon, Apr 5, 2021 at 2:01 AM Ilya Maximets <[email protected]> wrote:
>
> CC: ovs-dev
>
> On 4/4/21 7:50 PM, Ilya Maximets wrote:
> > 'struct ovs_zone_limit' has more members than initialized in
> > ovs_ct_limit_get_default_limit(). The rest of the memory is a random
> > kernel stack content that ends up being sent to userspace.
> >
> > Fix that by using designated initializer that will clear all
> > non-specified fields.
> >
> > Fixes: 11efd5cb04a1 ("openvswitch: Support conntrack zone limit")
> > Signed-off-by: Ilya Maximets <[email protected]>
> > ---
> > net/openvswitch/conntrack.c | 8 ++++----
> > 1 file changed, 4 insertions(+), 4 deletions(-)
> >
> > diff --git a/net/openvswitch/conntrack.c b/net/openvswitch/conntrack.c
> > index c29b0ef1fc27..cadb6a29b285 100644
> > --- a/net/openvswitch/conntrack.c
> > +++ b/net/openvswitch/conntrack.c
> > @@ -2032,10 +2032,10 @@ static int ovs_ct_limit_del_zone_limit(struct nlattr *nla_zone_limit,
> > static int ovs_ct_limit_get_default_limit(struct ovs_ct_limit_info *info,
> > struct sk_buff *reply)
> > {
> > - struct ovs_zone_limit zone_limit;
> > -
> > - zone_limit.zone_id = OVS_ZONE_LIMIT_DEFAULT_ZONE;
> > - zone_limit.limit = info->default_limit;
> > + struct ovs_zone_limit zone_limit = {
> > + .zone_id = OVS_ZONE_LIMIT_DEFAULT_ZONE,
> > + .limit = info->default_limit,
> > + };
I review the code, userspace don't use the count of ovs_zone_lime
struct, but this patch looks to to me.
Thanks Ilya.
Acked-by: Tonghao Zhang <[email protected]>
> > return nla_put_nohdr(reply, sizeof(zone_limit), &zone_limit);
> > }
> >
>
> _______________________________________________
> dev mailing list
> [email protected]
> https://mail.openvswitch.org/mailman/listinfo/ovs-dev



--
Best regards, Tonghao

2021-04-06 10:30:36

by patchwork-bot+netdevbpf

Subject: Re: [PATCH net] openvswitch: fix send of uninitialized stack memory in ct limit reply

Hello:

This patch was applied to netdev/net.git (refs/heads/master):

On Sun, 4 Apr 2021 19:50:31 +0200 you wrote:
> 'struct ovs_zone_limit' has more members than initialized in
> ovs_ct_limit_get_default_limit(). The rest of the memory is a random
> kernel stack content that ends up being sent to userspace.
>
> Fix that by using designated initializer that will clear all
> non-specified fields.
>
> [...]

Here is the summary with links:
- [net] openvswitch: fix send of uninitialized stack memory in ct limit reply
https://git.kernel.org/netdev/net/c/4d51419d4993

You are awesome, thank you!
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