[ovs-dev] openvswitch: add null pointer check on upcall

Message ID 20171109135943.418-1-colin.king@canonical.com
State New
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Series
  • [ovs-dev] openvswitch: add null pointer check on upcall
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Commit Message

Colin King Nov. 9, 2017, 1:59 p.m.
From: Colin Ian King <colin.king@canonical.com>

upcall may be assigned a NULL pointer as genlmsg_put can potentially
return a NULL.  Add a null check to avoid a null pointer dereference
on upcall.

Detected by CoverityScan, CID#728404 ("Dereference null return value")

Fixes: commit ccb1352e76cf ("net: Add Open vSwitch kernel components.")
Signed-off-by: Colin Ian King <colin.king@canonical.com>
---
 net/openvswitch/datapath.c | 4 ++++
 1 file changed, 4 insertions(+)

Comments

Pravin Shelar Nov. 9, 2017, 2:06 p.m. | #1
On Thu, Nov 9, 2017 at 7:29 PM, Colin King <colin.king@canonical.com> wrote:
> From: Colin Ian King <colin.king@canonical.com>
>
> upcall may be assigned a NULL pointer as genlmsg_put can potentially
> return a NULL.  Add a null check to avoid a null pointer dereference
> on upcall.
>
> Detected by CoverityScan, CID#728404 ("Dereference null return value")
>
> Fixes: commit ccb1352e76cf ("net: Add Open vSwitch kernel components.")
> Signed-off-by: Colin Ian King <colin.king@canonical.com>
> ---
>  net/openvswitch/datapath.c | 4 ++++
>  1 file changed, 4 insertions(+)
>
> diff --git a/net/openvswitch/datapath.c b/net/openvswitch/datapath.c
> index 4d38ac044cee..e8fb3d76fa6e 100644
> --- a/net/openvswitch/datapath.c
> +++ b/net/openvswitch/datapath.c
> @@ -461,6 +461,10 @@ static int queue_userspace_packet(struct datapath *dp, struct sk_buff *skb,
>
>         upcall = genlmsg_put(user_skb, 0, 0, &dp_packet_genl_family,
>                              0, upcall_info->cmd);
> +       if (!upcall) {
> +               err = -ENOBUFS;
> +               goto out;
> +       }
user_skb is allocated according to all required attributes, so
genlmsg_put() can not return null value.


>         upcall->dp_ifindex = dp_ifindex;
>
>         err = ovs_nla_put_key(key, key, OVS_PACKET_ATTR_KEY, false, user_skb);
> --
> 2.14.1
>
> _______________________________________________
> dev mailing list
> dev@openvswitch.org
> https://mail.openvswitch.org/mailman/listinfo/ovs-dev

Patch

diff --git a/net/openvswitch/datapath.c b/net/openvswitch/datapath.c
index 4d38ac044cee..e8fb3d76fa6e 100644
--- a/net/openvswitch/datapath.c
+++ b/net/openvswitch/datapath.c
@@ -461,6 +461,10 @@  static int queue_userspace_packet(struct datapath *dp, struct sk_buff *skb,
 
 	upcall = genlmsg_put(user_skb, 0, 0, &dp_packet_genl_family,
 			     0, upcall_info->cmd);
+	if (!upcall) {
+		err = -ENOBUFS;
+		goto out;
+	}
 	upcall->dp_ifindex = dp_ifindex;
 
 	err = ovs_nla_put_key(key, key, OVS_PACKET_ATTR_KEY, false, user_skb);