crypto: api - Add fips_enable flag

Add the ability to turn FIPS-compliant mode on or off at boot

In order to be FIPS compliant, several check may need to be preformed that may
be construed as unusefull in a non-compliant mode.  This patch allows us to set
a kernel flag incating that we are running in a fips-compliant mode from boot
up.  It also exports that mode information to user space via a sysctl
(/proc/sys/crypto/fips_enabled).

Tested successfully by me.
Signed-off-by: Neil Horman <nhorman@tuxdriver.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

crypto/Kconfig

@@ -21,6 +21,14 @@ if CRYPTO
 
 comment "Crypto core or helper"
 
+config CRYPTO_FIPS
+	bool "FIPS 200 compliance"
+	help
+	  This options enables the fips boot option which is
+	  required if you want to system to operate in a FIPS 200
+	  certification.  You should say no unless you know what
+	  this is.
+
 config CRYPTO_ALGAPI
 	tristate
 	help

crypto/Makefile

@@ -5,6 +5,8 @@
 obj-$(CONFIG_CRYPTO) += crypto.o
 crypto-objs := api.o cipher.o digest.o compress.o
 
+obj-$(CONFIG_CRYPTO_FIPS) += fips.o
+
 crypto_algapi-$(CONFIG_PROC_FS) += proc.o
 crypto_algapi-objs := algapi.o scatterwalk.o $(crypto_algapi-y)
 obj-$(CONFIG_CRYPTO_ALGAPI) += crypto_algapi.o

crypto/fips.c

+/*
+ * FIPS 200 support.
+ *
+ * Copyright (c) 2008 Neil Horman <nhorman@tuxdriver.com>
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License as published by the Free
+ * Software Foundation; either version 2 of the License, or (at your option)
+ * any later version.
+ *
+ */
+
+#include "internal.h"
+
+int fips_enabled;
+EXPORT_SYMBOL_GPL(fips_enabled);
+
+/* Process kernel command-line parameter at boot time. fips=0 or fips=1 */
+static int fips_enable(char *str)
+{
+	fips_enabled = !!simple_strtol(str, NULL, 0);
+	printk(KERN_INFO "fips mode: %s\n",
+		fips_enabled ? "enabled" : "disabled");
+	return 1;
+}
+
+__setup("fips=", fips_enable);

crypto/internal.h

@@ -26,6 +26,12 @@
 #include <linux/rwsem.h>
 #include <linux/slab.h>
 
+#ifdef CONFIG_CRYPTO_FIPS
+extern int fips_enabled;
+#else
+#define fips_enabled 0
+#endif
+
 /* Crypto notification events. */
 enum {
 	CRYPTO_MSG_ALG_REQUEST,

crypto/proc.c

@@ -19,8 +19,53 @@
 #include <linux/rwsem.h>
 #include <linux/proc_fs.h>
 #include <linux/seq_file.h>
+#include <linux/sysctl.h>
 #include "internal.h"
 
+#ifdef CONFIG_CRYPTO_FIPS
+static struct ctl_table crypto_sysctl_table[] = {
+	{
+		.ctl_name       = CTL_UNNUMBERED,
+		.procname       = "fips_enabled",
+		.data           = &fips_enabled,
+		.maxlen         = sizeof(int),
+		.mode           = 0444,
+		.proc_handler   = &proc_dointvec
+	},
+	{
+		.ctl_name = 0,
+	},
+};
+
+static struct ctl_table crypto_dir_table[] = {
+	{
+		.ctl_name       = CTL_UNNUMBERED,
+		.procname       = "crypto",
+		.mode           = 0555,
+		.child          = crypto_sysctl_table
+	},
+	{
+		.ctl_name = 0,
+	},
+};
+
+static struct ctl_table_header *crypto_sysctls;
+
+static void crypto_proc_fips_init(void)
+{
+	crypto_sysctls = register_sysctl_table(crypto_dir_table);
+}
+
+static void crypto_proc_fips_exit(void)
+{
+	if (crypto_sysctls)
+		unregister_sysctl_table(crypto_sysctls);
+}
+#else
+#define crypto_proc_fips_init()
+#define crypto_proc_fips_exit()
+#endif
+
 static void *c_start(struct seq_file *m, loff_t *pos)
 {
 	down_read(&crypto_alg_sem);
@@ -106,9 +151,11 @@ static const struct file_operations proc_crypto_ops = {
 void __init crypto_init_proc(void)
 {
 	proc_create("crypto", 0, NULL, &proc_crypto_ops);
+	crypto_proc_fips_init();
 }
 
 void __exit crypto_exit_proc(void)
 {
+	crypto_proc_fips_exit();
 	remove_proc_entry("crypto", NULL);
 }