[RFC][PATCH 3/3] IPv4:Check IP_MULTICAST_LOOP option value

[Shan Wei <shanwei@cn.fujitsu.com>]

The IP_MULTICAST_LOOP option can only be set with o or 1. When 
other valuse are set, the kernel should return an error of EINVAL.

In addition, the option should not be uesd by SOCK_STREAM type,
same as IP_MULTICAST_IF, IP_MULTICAST_TTL.
  
But the kernel doesn't check them.

Signed-off-by: Shan Wei<shanwei@cn.fujitsu.com>
---
 net/ipv4/ip_sockglue.c |    4 ++++
 1 files changed, 4 insertions(+), 0 deletions(-)

diff --git a/net/ipv4/ip_sockglue.c b/net/ipv4/ip_sockglue.c
index e0514e8..82196a5 100644
--- a/net/ipv4/ip_sockglue.c
+++ b/net/ipv4/ip_sockglue.c
@@ -558,8 +558,12 @@ static int do_ip_setsockopt(struct sock *sk, int level,
 		inet->mc_ttl = val;
 		break;
 	case IP_MULTICAST_LOOP:
+		if (sk->sk_type == SOCK_STREAM)
+			goto e_inval;
 		if (optlen<1)
 			goto e_inval;
+		if (val < 0 || val > 1)
+			goto e_inval;
 		inet->mc_loop = !!val;
 		break;
 	case IP_MULTICAST_IF:
-- 
1.5.4.4