crypto: fips - add FIPS test failure notification chain

Crypto test failures in FIPS mode cause an immediate panic, but
on some system the cryptographic boundary extends beyond just
the Linux controlled domain.

Add a simple atomic notification chain to allow interested parties
to register to receive notification prior to us kicking the bucket.

Signed-off-by: Gilad Ben-Yossef <gilad@benyossef.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

crypto/fips.c

@@ -11,10 +11,14 @@
 #include <linux/module.h>
 #include <linux/kernel.h>
 #include <linux/sysctl.h>
+#include <linux/notifier.h>
 
 int fips_enabled;
 EXPORT_SYMBOL_GPL(fips_enabled);
 
+ATOMIC_NOTIFIER_HEAD(fips_fail_notif_chain);
+EXPORT_SYMBOL_GPL(fips_fail_notif_chain);
+
 /* Process kernel command-line parameter at boot time. fips=0 or fips=1 */
 static int fips_enable(char *str)
 {
@@ -58,6 +62,13 @@ static void crypto_proc_fips_exit(void)
 	unregister_sysctl_table(crypto_sysctls);
 }
 
+void fips_fail_notify(void)
+{
+	if (fips_enabled)
+		atomic_notifier_call_chain(&fips_fail_notif_chain, 0, NULL);
+}
+EXPORT_SYMBOL_GPL(fips_fail_notify);
+
 static int __init fips_init(void)
 {
 	crypto_proc_fips_init();

crypto/testmgr.c

@@ -5240,9 +5240,11 @@ int alg_test(const char *driver, const char *alg, u32 type, u32 mask)
 					     type, mask);
 
 test_done:
-	if (rc && (fips_enabled || panic_on_fail))
+	if (rc && (fips_enabled || panic_on_fail)) {
+		fips_fail_notify();
 		panic("alg: self-tests for %s (%s) failed in %s mode!\n",
 		      driver, alg, fips_enabled ? "fips" : "panic_on_fail");
+	}
 
 	if (fips_enabled && !rc)
 		pr_info("alg: self-tests for %s (%s) passed\n", driver, alg);

include/linux/fips.h

@@ -4,8 +4,15 @@
 
 #ifdef CONFIG_CRYPTO_FIPS
 extern int fips_enabled;
+extern struct atomic_notifier_head fips_fail_notif_chain;
+
+void fips_fail_notify(void);
+
 #else
 #define fips_enabled 0
+
+static inline void fips_fail_notify(void) {}
+
 #endif
 
 #endif