net: Add compat ioctl support for the ipv4 multicast ioctl SIOCGETSGCNT

SIOCGETSGCNT is not a unique ioctl value as it it maps tio SIOCPROTOPRIVATE +1,
which unfortunately means the existing infrastructure for compat networking
ioctls is insufficient.  A trivial compact ioctl implementation would conflict
with:

SIOCAX25ADDUID
SIOCAIPXPRISLT
SIOCGETSGCNT_IN6
SIOCGETSGCNT
SIOCRSSCAUSE
SIOCX25SSUBSCRIP
SIOCX25SDTEFACILITIES

To make this work I have updated the compat_ioctl decode path to mirror the
the normal ioctl decode path.  I have added an ipv4 inet_compat_ioctl function
so that I can have ipv4 specific compat ioctls.   I have added a compat_ioctl
function into struct proto so I can break out ioctls by which kind of ip socket
I am using.  I have added a compat_raw_ioctl function because SIOCGETSGCNT only
works on raw sockets.  I have added a ipmr_compat_ioctl that mirrors the normal
ipmr_ioctl.

This was necessary because unfortunately the struct layout for the SIOCGETSGCNT
has unsigned longs in it so changes between 32bit and 64bit kernels.

This change was sufficient to run a 32bit ip multicast routing daemon on a
64bit kernel.

Reported-by: Bill Fenner <fenner@aristanetworks.com>
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 19 insertions, 0 deletions

diff --git a/net/ipv4/raw.c b/net/ipv4/raw.c
index a3d5ab7..6390ba2 100644
--- a/net/ipv4/raw.c
+++ b/net/ipv4/raw.c
@@ -76,6 +76,7 @@
 #include <linux/seq_file.h>
 #include <linux/netfilter.h>
 #include <linux/netfilter_ipv4.h>
+#include <linux/compat.h>
 
 static struct raw_hashinfo raw_v4_hashinfo = {
 	.lock = __RW_LOCK_UNLOCKED(raw_v4_hashinfo.lock),
@@ -838,6 +839,23 @@ static int raw_ioctl(struct sock *sk, int cmd, unsigned long arg)
 	}
 }
 
+#ifdef CONFIG_COMPAT
+static int compat_raw_ioctl(struct sock *sk, unsigned int cmd, unsigned long arg)
+{
+	switch (cmd) {
+	case SIOCOUTQ:
+	case SIOCINQ:
+		return -ENOIOCTLCMD;
+	default:
+#ifdef CONFIG_IP_MROUTE
+		return ipmr_compat_ioctl(sk, cmd, compat_ptr(arg));
+#else
+		return -ENOIOCTLCMD;
+#endif
+	}
+}
+#endif
+
 struct proto raw_prot = {
 	.name		   = "RAW",
 	.owner		   = THIS_MODULE,
@@ -860,6 +878,7 @@ struct proto raw_prot = {
 #ifdef CONFIG_COMPAT
 	.compat_setsockopt = compat_raw_setsockopt,
 	.compat_getsockopt = compat_raw_getsockopt,
+	.compat_ioctl	   = compat_raw_ioctl,
 #endif
 };