Messages in this thread | | | Date | Thu, 01 Aug 2013 10:24:19 -0700 | From | John Fastabend <> | Subject | Re: [PATCH v2] macvlan: validate flags |
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On 8/1/2013 9:09 AM, Michael S. Tsirkin wrote: > 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@davemloft.net> > Cc: John Fastabend <john.r.fastabend@intel.com> > Signed-off-by: Michael S. Tsirkin <mst@redhat.com> > --- > > 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. >
Agreed and because we haven't added more flags yet this shouldn't break uapi. Thanks for catching this.
> > drivers/net/macvlan.c | 7 +++++++ > 1 file changed, 7 insertions(+) >
By the same logic should we also add the check to macvlan_changelink()?
> 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[]) > return -EADDRNOTAVAIL; > } > > + if (data && data[IFLA_MACVLAN_FLAGS] && > + nla_get_u16(data[IFLA_MACVLAN_FLAGS]) & ~MACVLAN_FLAG_NOPROMISC) > + return -EINVAL; > + > if (data && data[IFLA_MACVLAN_MODE]) { > switch (nla_get_u32(data[IFLA_MACVLAN_MODE])) { > case MACVLAN_MODE_PRIVATE: > @@ -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; > +
Is there really a case where newlink is called without first calling validate? I don't think there is so the snippet here in newlink could be dropped.
Thanks, John
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