gre: fix a regression in ioctl

[ Upstream commit 6c734fb8592f6768170e48e7102cb2f0a1bb9759 ]

When testing GRE tunnel, I got:

 # ip tunnel show
 get tunnel gre0 failed: Invalid argument
 get tunnel gre1 failed: Invalid argument

This is a regression introduced by commit c54419321455631079c7d
("GRE: Refactor GRE tunneling code.") because previously we
only check the parameters for SIOCADDTUNNEL and SIOCCHGTUNNEL,
after that commit, the check is moved for all commands.

So, just check for SIOCADDTUNNEL and SIOCCHGTUNNEL.

After this patch I got:

 # ip tunnel show
 gre0: gre/ip  remote any  local any  ttl inherit  nopmtudisc
 gre1: gre/ip  remote 192.168.122.101  local 192.168.122.45  ttl inherit

Signed-off-by: Cong Wang <amwang@redhat.com>
Cc: Pravin B Shelar <pshelar@nicira.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/net/ipv4/ip_gre.c b/net/ipv4/ip_gre.c
index 2a83591492dd6f3e8b7470c3e9b897dad7625a49..855004f08325c86e0404b3e4cfa380da13fd81d0 100644 (file)
--- a/net/ipv4/ip_gre.c
+++ b/net/ipv4/ip_gre.c
@@ -503,10 +503,11 @@ static int ipgre_tunnel_ioctl(struct net_device *dev,
 
        if (copy_from_user(&p, ifr->ifr_ifru.ifru_data, sizeof(p)))
                return -EFAULT;
-       if (p.iph.version != 4 || p.iph.protocol != IPPROTO_GRE ||
-           p.iph.ihl != 5 || (p.iph.frag_off&htons(~IP_DF)) ||
-           ((p.i_flags|p.o_flags)&(GRE_VERSION|GRE_ROUTING))) {
-               return -EINVAL;
+       if (cmd == SIOCADDTUNNEL || cmd == SIOCCHGTUNNEL) {
+               if (p.iph.version != 4 || p.iph.protocol != IPPROTO_GRE ||
+                   p.iph.ihl != 5 || (p.iph.frag_off&htons(~IP_DF)) ||
+                   ((p.i_flags|p.o_flags)&(GRE_VERSION|GRE_ROUTING)))
+                       return -EINVAL;
        }
        p.i_flags = gre_flags_to_tnl_flags(p.i_flags);
        p.o_flags = gre_flags_to_tnl_flags(p.o_flags);