Merge branch 'net-socket-Fix-potential-spectre-v1-gadgets'

Jeremy Cline says:

====================
net: socket: Fix potential spectre v1 gadgets

This fixes a pair of potential spectre v1 gadgets.

Note that because the speculation window is large, the policy is to stop
the speculative out-of-bounds load and not worry if the attack can be
completed with a dependent load or store[0].

[0] https://marc.info/?l=linux-kernel&m=152449131114778
====================
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

net/socket.c

@@ -89,6 +89,7 @@
 #include <linux/magic.h>
 #include <linux/slab.h>
 #include <linux/xattr.h>
+#include <linux/nospec.h>
 
 #include <linux/uaccess.h>
 #include <asm/unistd.h>
@@ -2522,6 +2523,7 @@ SYSCALL_DEFINE2(socketcall, int, call, unsigned long __user *, args)
 
 	if (call < 1 || call > SYS_SENDMMSG)
 		return -EINVAL;
+	call = array_index_nospec(call, SYS_SENDMMSG + 1);
 
 	len = nargs[call];
 	if (len > sizeof(a))
@@ -2688,7 +2690,8 @@ EXPORT_SYMBOL(sock_unregister);
 
 bool sock_is_registered(int family)
 {
-	return family < NPROTO && rcu_access_pointer(net_families[family]);
+	return family < NPROTO &&
+		rcu_access_pointer(net_families[array_index_nospec(family, NPROTO)]);
 }
 
 static int __init sock_init(void)