2020-09-25 00:31:21

by Florian Fainelli

Subject: [PATCH net-next v2] net: vlan: Avoid using BUG() in vlan_proto_idx()

While we should always make sure that we specify a valid VLAN protocol
to vlan_proto_idx(), killing the machine when an invalid value is
specified is too harsh and not helpful for debugging. All callers are
capable of dealing with an error returned by vlan_proto_idx() so check
the index value and propagate it accordingly.

Signed-off-by: Florian Fainelli <[email protected]>
---
Changes in v2:
- changed signature to return int
- changed message to use ntohs()
- renamed an index variable to 'pidx' instead of 'pdix'

net/8021q/vlan.c | 3 +++
net/8021q/vlan.h | 19 +++++++++++++------
2 files changed, 16 insertions(+), 6 deletions(-)

diff --git a/net/8021q/vlan.c b/net/8021q/vlan.c
index d4bcfd8f95bf..6c08de1116c1 100644
--- a/net/8021q/vlan.c
+++ b/net/8021q/vlan.c
@@ -57,6 +57,9 @@ static int vlan_group_prealloc_vid(struct vlan_group *vg,
ASSERT_RTNL();

pidx = vlan_proto_idx(vlan_proto);
+ if (pidx < 0)
+ return -EINVAL;
+
vidx = vlan_id / VLAN_GROUP_ARRAY_PART_LEN;
array = vg->vlan_devices_arrays[pidx][vidx];
if (array != NULL)
diff --git a/net/8021q/vlan.h b/net/8021q/vlan.h
index bb7ec1a3915d..953405362795 100644
--- a/net/8021q/vlan.h
+++ b/net/8021q/vlan.h
@@ -36,7 +36,7 @@ struct vlan_info {
struct rcu_head rcu;
};

-static inline unsigned int vlan_proto_idx(__be16 proto)
+static inline int vlan_proto_idx(__be16 proto)
{
switch (proto) {
case htons(ETH_P_8021Q):
@@ -44,8 +44,8 @@ static inline unsigned int vlan_proto_idx(__be16 proto)
case htons(ETH_P_8021AD):
return VLAN_PROTO_8021AD;
default:
- BUG();
- return 0;
+ WARN(1, "invalid VLAN protocol: 0x%04x\n", ntohs(proto));
+ return -EINVAL;
}
}

@@ -64,17 +64,24 @@ static inline struct net_device *vlan_group_get_device(struct vlan_group *vg,
__be16 vlan_proto,
u16 vlan_id)
{
- return __vlan_group_get_device(vg, vlan_proto_idx(vlan_proto), vlan_id);
+ int pidx = vlan_proto_idx(vlan_proto);
+
+ if (pidx < 0)
+ return NULL;
+
+ return __vlan_group_get_device(vg, pidx, vlan_id);
}

static inline void vlan_group_set_device(struct vlan_group *vg,
__be16 vlan_proto, u16 vlan_id,
struct net_device *dev)
{
+ int pidx = vlan_proto_idx(vlan_proto);
struct net_device **array;
- if (!vg)
+
+ if (!vg || pidx < 0)
return;
- array = vg->vlan_devices_arrays[vlan_proto_idx(vlan_proto)]
+ array = vg->vlan_devices_arrays[pidx]
[vlan_id / VLAN_GROUP_ARRAY_PART_LEN];
array[vlan_id % VLAN_GROUP_ARRAY_PART_LEN] = dev;
}
--
2.25.1

2020-09-25 21:15:25

by David Miller

Subject: Re: [PATCH net-next v2] net: vlan: Avoid using BUG() in vlan_proto_idx()

From: Florian Fainelli <[email protected]>
Date: Thu, 24 Sep 2020 17:27:44 -0700

> While we should always make sure that we specify a valid VLAN protocol
> to vlan_proto_idx(), killing the machine when an invalid value is
> specified is too harsh and not helpful for debugging. All callers are
> capable of dealing with an error returned by vlan_proto_idx() so check
> the index value and propagate it accordingly.
>
> Signed-off-by: Florian Fainelli <[email protected]>
> ---
> Changes in v2:
> - changed signature to return int
> - changed message to use ntohs()
> - renamed an index variable to 'pidx' instead of 'pdix'

Applied, thanks Florian.

2020-09-25 21:21:44

by Vladimir Oltean

Subject: Re: [PATCH net-next v2] net: vlan: Avoid using BUG() in vlan_proto_idx()

On Fri, Sep 25, 2020 at 02:12:34PM -0700, David Miller wrote:
> From: Florian Fainelli <[email protected]>
> Date: Thu, 24 Sep 2020 17:27:44 -0700
>
> Applied, thanks Florian.

Uh-oh, that 'negative value stored in unsigned variable' issue that the
build bot reported was on v2, wasn't it?

2020-09-28 02:18:01

by Florian Fainelli

Subject: Re: [PATCH net-next v2] net: vlan: Avoid using BUG() in vlan_proto_idx()

On 9/25/2020 2:20 PM, Vladimir Oltean wrote:
> On Fri, Sep 25, 2020 at 02:12:34PM -0700, David Miller wrote:
>> From: Florian Fainelli <[email protected]>
>> Date: Thu, 24 Sep 2020 17:27:44 -0700
>>
>> Applied, thanks Florian.
>
> Uh-oh, that 'negative value stored in unsigned variable' issue that the
> build bot reported was on v2, wasn't it?

Yes, I will be sending a fixup now.
--
Florian