ipv6 RAW: Disallow IPPROTO_IPV6-level IPV6_CHECKSUM socket option on ICMPv6 sockets.

RFC3542 tells that IPV6_CHECKSUM socket option in the IPPROTO_IPV6
level is not allowed on ICMPv6 sockets.  IPPROTO_RAW level
IPV6_CHECKSUM socket option (a Linux extension) is still allowed.

Signed-off-by: YOSHIFUJI Hideaki <yoshfuji@linux-ipv6.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 18 insertions, 0 deletions

diff --git a/net/ipv6/raw.c b/net/ipv6/raw.c
index 6193b124cbc7..396f0ea11090 100644
--- a/net/ipv6/raw.c
+++ b/net/ipv6/raw.c
@@ -971,6 +971,19 @@ static int do_rawv6_setsockopt(struct sock *sk, int level, int optname,
 
         switch (optname) {
                 case IPV6_CHECKSUM:
+                        if (inet_sk(sk)->num == IPPROTO_ICMPV6 &&
+                            level == IPPROTO_IPV6) {
+                                /*
+                                 * RFC3542 tells that IPV6_CHECKSUM socket
+                                 * option in the IPPROTO_IPV6 level is not
+                                 * allowed on ICMPv6 sockets.
+                                 * If you want to set it, use IPPROTO_RAW
+                                 * level IPV6_CHECKSUM socket option
+                                 * (Linux extension).
+                                 */
+                                return -EINVAL;
+                        }
+
                         /* You may get strange result with a positive odd offset;
                            RFC2292bis agrees with me. */
                         if (val > 0 && (val&1))
@@ -1046,6 +1059,11 @@ static int do_rawv6_getsockopt(struct sock *sk, int level, int optname,
 
         switch (optname) {
         case IPV6_CHECKSUM:
+                /*
+                 * We allow getsockopt() for IPPROTO_IPV6-level
+                 * IPV6_CHECKSUM socket option on ICMPv6 sockets
+                 * since RFC3542 is silent about it.
+                 */
                 if (rp->checksum == 0)
                         val = -1;
                 else