[PATCH v2] macvlan: validate flags

From: Michael S. Tsirkin
Date: Thu Aug 01 2013 - 12:08:10 EST

commit df8ef8f3aaa6692970a436204c4429210addb23a
macvlan: add FDB bridge ops and macvlan flags
added a flags field to macvlan, which can be
controlled from userspace.
The idea is to make the interface future-proof
so we can add flags and not new fields.

However, flags value isn't validated, as a result,
userspace can't detect which flags are supported.

Cc: "David S. Miller" <davem@xxxxxxxxxxxxx>
Cc: John Fastabend <john.r.fastabend@xxxxxxxxx>
Signed-off-by: Michael S. Tsirkin <mst@xxxxxxxxxx>

Changes from v1:
tweaked commit message
no code changes

Please consider this patch for -stable.

The idea is by the time we add more flags,
everyone has updated to a kernel that
detects errors, so userspace will be able
to detect supported flags cleanly.

drivers/net/macvlan.c | 7 +++++++
1 file changed, 7 insertions(+)

diff --git a/drivers/net/macvlan.c b/drivers/net/macvlan.c
index 18373b6..8445a94 100644
--- a/drivers/net/macvlan.c
+++ b/drivers/net/macvlan.c
@@ -736,6 +736,10 @@ static int macvlan_validate(struct nlattr *tb[], struct nlattr *data[])

+ if (data && data[IFLA_MACVLAN_FLAGS] &&
+ return -EINVAL;
if (data && data[IFLA_MACVLAN_MODE]) {
switch (nla_get_u32(data[IFLA_MACVLAN_MODE])) {
@@ -809,6 +813,9 @@ int macvlan_common_newlink(struct net *src_net, struct net_device *dev,
if (data && data[IFLA_MACVLAN_FLAGS])
vlan->flags = nla_get_u16(data[IFLA_MACVLAN_FLAGS]);

+ if (vlan->flags & ~MACVLAN_FLAG_NOPROMISC)
+ return -EINVAL;
if (vlan->mode == MACVLAN_MODE_PASSTHRU) {
if (port->count)
return -EINVAL;
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