ip6mr: limit IPv6 MRT_TABLE identifiers

We did this for IPv4 in b49d3c1e1c "net: ipmr: limit MRT_TABLE
identifiers" but we need to do it for IPv6 as well.  On IPv6 the name
is "pim6reg" instead of "pimreg" so there is one less digit allowed.

The strcpy() is in ip6mr_reg_vif().

Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 3 insertions, 0 deletions

diff --git a/net/ipv6/ip6mr.c b/net/ipv6/ip6mr.c
index 26dcdec9e3a5..8fd154e5f079 100644
--- a/net/ipv6/ip6mr.c
+++ b/net/ipv6/ip6mr.c
@@ -1710,6 +1710,9 @@ int ip6_mroute_setsockopt(struct sock *sk, int optname, char __user *optval, uns
                         return -EINVAL;
                 if (get_user(v, (u32 __user *)optval))
                         return -EFAULT;
+                /* "pim6reg%u" should not exceed 16 bytes (IFNAMSIZ) */
+                if (v != RT_TABLE_DEFAULT && v >= 100000000)
+                        return -EINVAL;
                 if (sk == mrt->mroute6_sk)
                         return -EBUSY;