[PATCH net 4/4] gtp: avoid zero size hashtable

[Taehee Yoo]

GTP default hashtable size is 1024 and userspace could set specific
hashtable size with IFLA_GTP_PDP_HASHSIZE. If hashtable size is set to 0
from userspace,  hashtable will not work and panic will occur.

Fixes: 459aa660eb1d ("gtp: add initial driver for datapath of GPRS Tunneling 
Protocol (GTP-U)")
Signed-off-by: Taehee Yoo <ap420...@gmail.com>
---
 drivers/net/gtp.c | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/drivers/net/gtp.c b/drivers/net/gtp.c
index 5450b1099c6d..e5b7d6d2286e 100644
--- a/drivers/net/gtp.c
+++ b/drivers/net/gtp.c
@@ -667,10 +667,13 @@ static int gtp_newlink(struct net *src_net, struct 
net_device *dev,
        if (err < 0)
                return err;
 
-       if (!data[IFLA_GTP_PDP_HASHSIZE])
+       if (!data[IFLA_GTP_PDP_HASHSIZE]) {
                hashsize = 1024;
-       else
+       } else {
                hashsize = nla_get_u32(data[IFLA_GTP_PDP_HASHSIZE]);
+               if (!hashsize)
+                       hashsize = 1024;
+       }
 
        err = gtp_hashtable_new(gtp, hashsize);
        if (err < 0)
-- 
2.17.1