net: Fix references to out-of-scope variables in put_cmsg_compat()

In net/compat.c::put_cmsg_compat() we may assign 'data' the address of
either the 'ctv' or 'cts' local variables inside the 'if
(!COMPAT_USE_64BIT_TIME)' branch.

Those variables go out of scope at the end of the 'if' statement, so
when we use 'data' further down in 'copy_to_user(CMSG_COMPAT_DATA(cm),
data, cmlen - sizeof(struct compat_cmsghdr))' there's no telling what
it may be refering to - not good.

Fix the problem by simply giving 'ctv' and 'cts' function scope.
Signed-off-by: NJesper Juhl <jj@chaosbits.net>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

net/compat.c

@@ -221,6 +221,8 @@ int put_cmsg_compat(struct msghdr *kmsg, int level, int type, int len, void *dat
 {
 	struct compat_cmsghdr __user *cm = (struct compat_cmsghdr __user *) kmsg->msg_control;
 	struct compat_cmsghdr cmhdr;
+	struct compat_timeval ctv;
+	struct compat_timespec cts[3];
 	int cmlen;
 
 	if (cm == NULL || kmsg->msg_controllen < sizeof(*cm)) {
@@ -229,8 +231,6 @@ int put_cmsg_compat(struct msghdr *kmsg, int level, int type, int len, void *dat
 	}
 
 	if (!COMPAT_USE_64BIT_TIME) {
-		struct compat_timeval ctv;
-		struct compat_timespec cts[3];
 		if (level == SOL_SOCKET && type == SCM_TIMESTAMP) {
 			struct timeval *tv = (struct timeval *)data;
 			ctv.tv_sec = tv->tv_sec;