linux-kernel - [PATCH v3] crypto: Add a flag allowing the self-tests to be disabled at runtime.

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Date:	Tue,  3 May 2016 10:00:17 +0100
From:	"Richard W.M. Jones" <rjones@...hat.com>
To:	linux-kernel@...r.kernel.org
Cc:	linux-crypto@...r.kernel.org, linux-doc@...r.kernel.org,
	corbet@....net, herbert@...dor.apana.org.au, davem@...emloft.net,
	sm@...rm.de
Subject: [PATCH v3] crypto: Add a flag allowing the self-tests to be disabled at runtime.

Running self-tests for a short-lived KVM VM takes 28ms on my laptop.
This commit adds a flag 'cryptomgr.notests' which allows them to be
disabled.

However if fips=1 as well, we ignore this flag as FIPS mode mandates
that the self-tests are run.

Signed-off-by: Richard W.M. Jones <rjones@...hat.com>
---
 Documentation/kernel-parameters.txt | 3 +++
 crypto/testmgr.c                    | 9 +++++++++
 2 files changed, 12 insertions(+)

diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt
index 0b3de80..d4d5fb7 100644
--- a/Documentation/kernel-parameters.txt
+++ b/Documentation/kernel-parameters.txt
@@ -826,6 +826,9 @@ bytes respectively. Such letter suffixes can also be entirely omitted.
 			It will be ignored when crashkernel=X,high is not used
 			or memory reserved is below 4G.
 
+	cryptomgr.notests
+                        [KNL] Disable crypto self-tests
+
 	cs89x0_dma=	[HW,NET]
 			Format: <dma>
 
diff --git a/crypto/testmgr.c b/crypto/testmgr.c
index b86883a..fcd89fe 100644
--- a/crypto/testmgr.c
+++ b/crypto/testmgr.c
@@ -35,6 +35,10 @@
 
 #include "internal.h"
 
+static bool notests;
+module_param(notests, bool, 0644);
+MODULE_PARM_DESC(notests, "disable crypto self-tests");
+
 #ifdef CONFIG_CRYPTO_MANAGER_DISABLE_TESTS
 
 /* a perfect nop */
@@ -3868,6 +3872,11 @@ int alg_test(const char *driver, const char *alg, u32 type, u32 mask)
 	int j;
 	int rc;
 
+	if (!fips_enabled && notests) {
+		printk_once(KERN_INFO "alg: self-tests disabled\n");
+		return 0;
+	}
+
 	alg_test_descs_check_order();
 
 	if ((type & CRYPTO_ALG_TYPE_MASK) == CRYPTO_ALG_TYPE_CIPHER) {
-- 
2.7.4