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Subject[PATCH 2/2] crypto: caam - support tagged keys for skcipher algorithms
Date
Tagged keys are keys that contain metadata indicating what
they are and how to handle them using tag_object API.

Add support, for tagged keys, to skcipher algorithms by
adding new transformations, with _tk_ prefix to distinguish
between plaintext and tagged keys.

For job descriptors a new option (key_cmd_opt) was added for KEY command.
Tagged keys can be loaded using only a KEY command with ENC=1
and the proper setting of the EKT bit. The EKT bit in the
KEY command indicates which encryption algorithm (AES-ECB or
AES-CCM) should be used to decrypt the key. These options will be kept in
key_cmd_opt.

The tk_ transformations can be used directly by their name:
struct sockaddr_alg sa = {
.salg_family = AF_ALG,
.salg_type = "skcipher", /* this selects the symmetric cipher */
.salg_name = "tk(cbc(aes))" /* this is the cipher name */
};
or for dm-crypt, e.g. using dmsetup:
dmsetup -v create encrypted --table "0 $(blockdev --getsz /dev/mmcblk2p10)
crypt capi:tk(cbc(aes))-plain :32:logon:seckey 0 /dev/mmcblk2p10 0 1
sector_size:512".

Signed-off-by: Franck LENORMAND <franck.lenormand@nxp.com>
Signed-off-by: Iuliana Prodan <iuliana.prodan@nxp.com>
---
drivers/crypto/caam/caamalg.c | 107 +++++++++++++++++++++++++++++++++++--
drivers/crypto/caam/caamalg_desc.c | 28 ++++++++--
drivers/crypto/caam/desc_constr.h | 4 ++
3 files changed, 131 insertions(+), 8 deletions(-)

diff --git a/drivers/crypto/caam/caamalg.c b/drivers/crypto/caam/caamalg.c
index b2f9882..9e4206f 100644
--- a/drivers/crypto/caam/caamalg.c
+++ b/drivers/crypto/caam/caamalg.c
@@ -3,7 +3,7 @@
* caam - Freescale FSL CAAM support for crypto API
*
* Copyright 2008-2011 Freescale Semiconductor, Inc.
- * Copyright 2016-2019 NXP
+ * Copyright 2016-2020 NXP
*
* Based on talitos crypto API driver.
*
@@ -58,6 +58,10 @@
#include "caamalg_desc.h"
#include <crypto/engine.h>

+#ifdef CONFIG_CRYPTO_DEV_FSL_CAAM_TK_API
+#include "tag_object.h"
+#endif /* CONFIG_CRYPTO_DEV_FSL_CAAM_TK_API */
+
/*
* crypto alg
*/
@@ -84,6 +88,7 @@ struct caam_alg_entry {
bool rfc3686;
bool geniv;
bool nodkp;
+ bool support_tagged_key;
};

struct caam_aead_alg {
@@ -736,9 +741,16 @@ static int skcipher_setkey(struct crypto_skcipher *skcipher, const u8 *key,
print_hex_dump_debug("key in @"__stringify(__LINE__)": ",
DUMP_PREFIX_ADDRESS, 16, 4, key, keylen, 1);

- ctx->cdata.keylen = keylen;
- ctx->cdata.key_virt = key;
- ctx->cdata.key_inline = true;
+ /*
+ * If the algorithm has support for tagged key,
+ * this is already set in tk_skcipher_setkey().
+ * Otherwise, set here the algorithm details.
+ */
+ if (!alg->caam.support_tagged_key) {
+ ctx->cdata.keylen = keylen;
+ ctx->cdata.key_virt = key;
+ ctx->cdata.key_inline = true;
+ }

/* skcipher_encrypt shared descriptor */
desc = ctx->sh_desc_enc;
@@ -816,6 +828,56 @@ static int arc4_skcipher_setkey(struct crypto_skcipher *skcipher,
return skcipher_setkey(skcipher, key, keylen, 0);
}

+#ifdef CONFIG_CRYPTO_DEV_FSL_CAAM_TK_API
+static int tk_skcipher_setkey(struct crypto_skcipher *skcipher,
+ const u8 *key, unsigned int keylen)
+{
+ struct caam_ctx *ctx = crypto_skcipher_ctx(skcipher);
+ struct device *jrdev = ctx->jrdev;
+ struct header_conf *header;
+ int ret;
+
+ ctx->cdata.keylen = keylen;
+ ctx->cdata.key_virt = key;
+ ctx->cdata.key_inline = true;
+
+ /* Retrieve the address of the tag object configuration */
+ ret = get_tag_object_header_conf(ctx->cdata.key_virt,
+ ctx->cdata.keylen, &header);
+ if (ret) {
+ dev_err(jrdev,
+ "unable to get tag object header configuration\n");
+ return ret;
+ }
+
+ /* Check if the tag object header is a black key */
+ if (!is_black_key(header)) {
+ dev_err(jrdev,
+ "tagged key provided is not a black key\n");
+ return -EINVAL;
+ }
+
+ /* Retrieve the black key configuration */
+ get_key_conf(header,
+ &ctx->cdata.key_real_len,
+ &ctx->cdata.key_cmd_opt);
+
+ /*
+ * Retrieve the address of the data
+ * and size of the tagged object
+ */
+ ret = get_tagged_data(ctx->cdata.key_virt, ctx->cdata.keylen,
+ &ctx->cdata.key_virt, &ctx->cdata.keylen);
+ if (ret) {
+ dev_err(jrdev,
+ "unable to get data from tagged object\n");
+ return ret;
+ }
+
+ return skcipher_setkey(skcipher, key, keylen, 0);
+}
+#endif /* CONFIG_CRYPTO_DEV_FSL_CAAM_TK_API */
+
static int des_skcipher_setkey(struct crypto_skcipher *skcipher,
const u8 *key, unsigned int keylen)
{
@@ -1833,6 +1895,25 @@ static struct caam_skcipher_alg driver_algs[] = {
},
.caam.class1_alg_type = OP_ALG_ALGSEL_AES | OP_ALG_AAI_CBC,
},
+#ifdef CONFIG_CRYPTO_DEV_FSL_CAAM_TK_API
+ {
+ .skcipher = {
+ .base = {
+ .cra_name = "tk(cbc(aes))",
+ .cra_driver_name = "tk-cbc-aes-caam",
+ .cra_blocksize = AES_BLOCK_SIZE,
+ },
+ .setkey = tk_skcipher_setkey,
+ .encrypt = skcipher_encrypt,
+ .decrypt = skcipher_decrypt,
+ .min_keysize = TAG_MIN_SIZE,
+ .max_keysize = CAAM_MAX_KEY_SIZE,
+ .ivsize = AES_BLOCK_SIZE,
+ },
+ .caam.class1_alg_type = OP_ALG_ALGSEL_AES | OP_ALG_AAI_CBC,
+ .caam.support_tagged_key = true,
+ },
+#endif /* CONFIG_CRYPTO_DEV_FSL_CAAM_TK_API */
{
.skcipher = {
.base = {
@@ -1952,6 +2033,24 @@ static struct caam_skcipher_alg driver_algs[] = {
},
.caam.class1_alg_type = OP_ALG_ALGSEL_AES | OP_ALG_AAI_ECB,
},
+#ifdef CONFIG_CRYPTO_DEV_FSL_CAAM_TK_API
+ {
+ .skcipher = {
+ .base = {
+ .cra_name = "tk(ecb(aes))",
+ .cra_driver_name = "tk-ecb-aes-caam",
+ .cra_blocksize = AES_BLOCK_SIZE,
+ },
+ .setkey = tk_skcipher_setkey,
+ .encrypt = skcipher_encrypt,
+ .decrypt = skcipher_decrypt,
+ .min_keysize = TAG_MIN_SIZE,
+ .max_keysize = CAAM_MAX_KEY_SIZE,
+ },
+ .caam.class1_alg_type = OP_ALG_ALGSEL_AES | OP_ALG_AAI_ECB,
+ .caam.support_tagged_key = true,
+ },
+#endif /* CONFIG_CRYPTO_DEV_FSL_CAAM_TK_API */
{
.skcipher = {
.base = {
diff --git a/drivers/crypto/caam/caamalg_desc.c b/drivers/crypto/caam/caamalg_desc.c
index d6c5818..447f7a5 100644
--- a/drivers/crypto/caam/caamalg_desc.c
+++ b/drivers/crypto/caam/caamalg_desc.c
@@ -1389,8 +1389,18 @@ void cnstr_shdsc_skcipher_encap(u32 * const desc, struct alginfo *cdata,
JUMP_COND_SHRD);

/* Load class1 key only */
- append_key_as_imm(desc, cdata->key_virt, cdata->keylen,
- cdata->keylen, CLASS_1 | KEY_DEST_CLASS_REG);
+ if (IS_ENABLED(CONFIG_CRYPTO_DEV_FSL_CAAM_TK_API) &&
+ cdata->key_cmd_opt)
+ /*
+ * Black keys can be loaded using only a KEY command
+ * with ENC=1 and the proper setting of the EKT bit.
+ */
+ append_key_as_imm(desc, cdata->key_virt, cdata->keylen,
+ cdata->key_real_len, CLASS_1 |
+ KEY_DEST_CLASS_REG | cdata->key_cmd_opt);
+ else
+ append_key_as_imm(desc, cdata->key_virt, cdata->keylen,
+ cdata->keylen, CLASS_1 | KEY_DEST_CLASS_REG);

/* Load nonce into CONTEXT1 reg */
if (is_rfc3686) {
@@ -1464,8 +1474,18 @@ void cnstr_shdsc_skcipher_decap(u32 * const desc, struct alginfo *cdata,
JUMP_COND_SHRD);

/* Load class1 key only */
- append_key_as_imm(desc, cdata->key_virt, cdata->keylen,
- cdata->keylen, CLASS_1 | KEY_DEST_CLASS_REG);
+ if (IS_ENABLED(CONFIG_CRYPTO_DEV_FSL_CAAM_TK_API) &&
+ cdata->key_cmd_opt)
+ /*
+ * Black keys can be loaded using only a KEY command
+ * with ENC=1 and the proper setting of the EKT bit.
+ */
+ append_key_as_imm(desc, cdata->key_virt, cdata->keylen,
+ cdata->key_real_len, CLASS_1 |
+ KEY_DEST_CLASS_REG | cdata->key_cmd_opt);
+ else
+ append_key_as_imm(desc, cdata->key_virt, cdata->keylen,
+ cdata->keylen, CLASS_1 | KEY_DEST_CLASS_REG);

/* Load nonce into CONTEXT1 reg */
if (is_rfc3686) {
diff --git a/drivers/crypto/caam/desc_constr.h b/drivers/crypto/caam/desc_constr.h
index 62ce642..93b2ab0 100644
--- a/drivers/crypto/caam/desc_constr.h
+++ b/drivers/crypto/caam/desc_constr.h
@@ -500,6 +500,8 @@ do { \
* @key_virt: virtual address where algorithm key resides
* @key_inline: true - key can be inlined in the descriptor; false - key is
* referenced by the descriptor
+ * @key_real_len: size of the key to be loaded by the CAAM
+ * @key_cmd_opt: optional parameters for KEY command
*/
struct alginfo {
u32 algtype;
@@ -508,6 +510,8 @@ struct alginfo {
dma_addr_t key_dma;
const void *key_virt;
bool key_inline;
+ u32 key_real_len;
+ u32 key_cmd_opt;
};

/**
--
2.1.0
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