[PATCH 1/4] crypto: ccp - Allow for selective disablement of cryptoAPI algorithms

From: Tom Lendacky
Date: Fri Jan 24 2014 - 17:18:21 EST


Introduce module parameters that allow for disabling of a
crypto algorithm by not registering the algorithm with the
crypto API.

Signed-off-by: Tom Lendacky <thomas.lendacky@xxxxxxx>
---
drivers/crypto/ccp/ccp-crypto-main.c | 37 +++++++++++++++++++++++-----------
1 file changed, 25 insertions(+), 12 deletions(-)

diff --git a/drivers/crypto/ccp/ccp-crypto-main.c b/drivers/crypto/ccp/ccp-crypto-main.c
index 2636f04..b3f22b0 100644
--- a/drivers/crypto/ccp/ccp-crypto-main.c
+++ b/drivers/crypto/ccp/ccp-crypto-main.c
@@ -11,6 +11,7 @@
*/

#include <linux/module.h>
+#include <linux/moduleparam.h>
#include <linux/kernel.h>
#include <linux/list.h>
#include <linux/ccp.h>
@@ -24,6 +25,14 @@ MODULE_LICENSE("GPL");
MODULE_VERSION("1.0.0");
MODULE_DESCRIPTION("AMD Cryptographic Coprocessor crypto API support");

+static unsigned int aes_disable;
+module_param(aes_disable, uint, 0444);
+MODULE_PARM_DESC(aes_disable, "Disable use of AES - any non-zero value");
+
+static unsigned int sha_disable;
+module_param(sha_disable, uint, 0444);
+MODULE_PARM_DESC(sha_disable, "Disable use of SHA - any non-zero value");
+

/* List heads for the supported algorithms */
static LIST_HEAD(hash_algs);
@@ -337,21 +346,25 @@ static int ccp_register_algs(void)
{
int ret;

- ret = ccp_register_aes_algs(&cipher_algs);
- if (ret)
- return ret;
+ if (!aes_disable) {
+ ret = ccp_register_aes_algs(&cipher_algs);
+ if (ret)
+ return ret;

- ret = ccp_register_aes_cmac_algs(&hash_algs);
- if (ret)
- return ret;
+ ret = ccp_register_aes_cmac_algs(&hash_algs);
+ if (ret)
+ return ret;

- ret = ccp_register_aes_xts_algs(&cipher_algs);
- if (ret)
- return ret;
+ ret = ccp_register_aes_xts_algs(&cipher_algs);
+ if (ret)
+ return ret;
+ }

- ret = ccp_register_sha_algs(&hash_algs);
- if (ret)
- return ret;
+ if (!sha_disable) {
+ ret = ccp_register_sha_algs(&hash_algs);
+ if (ret)
+ return ret;
+ }

return 0;
}


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