Messages in this thread | | | Date | Thu, 1 Aug 2013 22:19:57 +0300 | From | "Michael S. Tsirkin" <> | Subject | Re: [PATCH v2] macvlan: validate flags |
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On Thu, Aug 01, 2013 at 10:24:19AM -0700, John Fastabend wrote: > 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()?
I'm not sure what do you mean "By the same logic" - macvlan_changelink is static unlike macvlan_common_newlink which is exported to modules. So why isn't macvlan_validate sufficient for 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
It seems so - macvtap_newlink calls macvlan_common_newlink. macvtap does not seem to have .validate.
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