Subject: [PATCH v3] crypto: add support for the NIST CMAC hash

From: Tom St Denis <[email-masked]>
Date: Wed, 23 Jan 2013 07:43:01 -0500 (EST)

Signed-off-by: Tom St Denis <[email-masked]>
---
 crypto/Kconfig               |   9 ++
 crypto/Makefile              |   1 +
 crypto/cmac.c                | 317 +++++++++++++++++++++++++++++++++++++++++++
 crypto/testmgr.c             |   9 ++
 crypto/testmgr.h             |  52 +++++++
 include/uapi/linux/pfkeyv2.h |   1 +
 net/xfrm/xfrm_algo.c         |  17 +++
 7 files changed, 406 insertions(+)
 create mode 100644 crypto/cmac.c

diff --git a/crypto/Kconfig b/crypto/Kconfig
index 4641d95..7ab11a9 100644
--- a/crypto/Kconfig
+++ b/crypto/Kconfig
@@ -301,6 +301,15 @@ config CRYPTO_XCBC
 		http://csrc.nist.gov/encryption/modes/proposedmodes/
 		 xcbc-mac/xcbc-mac-spec.pdf
 
+config CRYPTO_CMAC
+	tristate "CMAC support"
+	select CRYPTO_HASH
+	select CRYPTO_MANAGER
+	help
+	  NIST CMAC cipher based MAC algorithm
+	  http://tools.ietf.org/rfc/rfc4494.txt
+	  http://csrc.nist.gov/publications/nistpubs/800-38B/SP_800-38B.pdf
+
 config CRYPTO_VMAC
 	tristate "VMAC support"
 	depends on EXPERIMENTAL
diff --git a/crypto/Makefile b/crypto/Makefile
index d59dec7..85a615d 100644
--- a/crypto/Makefile
+++ b/crypto/Makefile
@@ -35,6 +35,7 @@ obj-$(CONFIG_CRYPTO_USER) += crypto_user.o
 obj-$(CONFIG_CRYPTO_HMAC) += hmac.o
 obj-$(CONFIG_CRYPTO_VMAC) += vmac.o
 obj-$(CONFIG_CRYPTO_XCBC) += xcbc.o
+obj-$(CONFIG_CRYPTO_CMAC) += cmac.o
 obj-$(CONFIG_CRYPTO_NULL) += crypto_null.o
 obj-$(CONFIG_CRYPTO_MD4) += md4.o
 obj-$(CONFIG_CRYPTO_MD5) += md5.o
diff --git a/crypto/cmac.c b/crypto/cmac.c
new file mode 100644
index 0000000..1ffeea7
--- /dev/null
+++ b/crypto/cmac.c
@@ -0,0 +1,317 @@
+/*
+ * Copyright (C)2006 USAGI/WIDE Project
+ *
+ * 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.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ *
+ * Author:
+ *	 Tom St Denis <[email-masked]>
+ *
+ * Derived from the XCBC code of:
+ *	 Kazunori Miyazawa <[email-masked]>
+ */
+
+#include <crypto/internal/hash.h>
+#include <linux/err.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+
+/*
+ * +------------------------
+ * | <parent tfm>
+ * +------------------------
+ * | cmac_tfm_ctx
+ * +------------------------
+ * | consts (block size * 2)
+ * +------------------------
+ */
+struct cmac_tfm_ctx {
+	struct crypto_cipher *child;
+	u8 ctx[];
+};
+
+/*
+ * +------------------------
+ * | <shash desc>
+ * +------------------------
+ * | cmac_desc_ctx
+ * +------------------------
+ * | odds (block size)
+ * +------------------------
+ * | prev (block size)
+ * +------------------------
+ */
+struct cmac_desc_ctx {
+	unsigned int len;
+	u8 ctx[];
+};
+
+static int crypto_cmac_digest_setkey(struct crypto_shash *parent,
+					  const u8 *inkey, unsigned int keylen)
+{
+	unsigned long alignmask = crypto_shash_alignmask(parent);
+	struct cmac_tfm_ctx *ctx = crypto_shash_ctx(parent);
+	int bs = crypto_shash_blocksize(parent);
+	u8 *consts = PTR_ALIGN(&ctx->ctx[0], alignmask + 1);
+	int x, y, err = 0;
+	u8 msb, mask;
+
+	switch (bs) {
+	case 16:
+		mask = 0x87;
+		break;
+	case 8:
+		mask = 0x1B;
+		break;
+	default:
+		return -EINVAL; /*  only support 64/128 bit block ciphers */
+	}
+
+	err = crypto_cipher_setkey(ctx->child, inkey, keylen);
+	if (err)
+		return err;
+
+	/* encrypt the zero block */
+	memset(consts, 0, bs);
+	crypto_cipher_encrypt_one(ctx->child, consts, consts);
+
+	for (x = 0; x < 2; x++) {
+		/* if msb(L * u^(x+1)) = 0 then just shift,
+		otherwise shift and xor constant mask */
+		msb = consts[x*bs + 0] >> 7;
+
+		/* shift left */
+		for (y = 0; y < (bs - 1); y++)
+			consts[x*bs + y] =
+				((consts[x*bs + y] << 1) |
+				(consts[x*bs + y+1] >> 7)) & 255;
+
+		consts[x*bs + bs - 1] =
+			((consts[x*bs + bs - 1] << 1) ^
+			(msb ? mask : 0)) & 255;
+
+		/* copy up as require */
+		if (x == 0)
+			memcpy(&consts[(x+1)*bs], &consts[x*bs], bs);
+	}
+	return 0;
+}
+
+static int crypto_cmac_digest_init(struct shash_desc *pdesc)
+{
+	unsigned long alignmask = crypto_shash_alignmask(pdesc->tfm);
+	struct cmac_desc_ctx *ctx = shash_desc_ctx(pdesc);
+	int bs = crypto_shash_blocksize(pdesc->tfm);
+	u8 *prev = PTR_ALIGN(&ctx->ctx[0], alignmask + 1) + bs;
+
+	ctx->len = 0;
+	memset(prev, 0, bs);
+
+	return 0;
+}
+
+static int crypto_cmac_digest_update(struct shash_desc *pdesc, const u8 *p,
+					  unsigned int len)
+{
+	struct crypto_shash *parent = pdesc->tfm;
+	unsigned long alignmask = crypto_shash_alignmask(parent);
+	struct cmac_tfm_ctx *tctx = crypto_shash_ctx(parent);
+	struct cmac_desc_ctx *ctx = shash_desc_ctx(pdesc);
+	struct crypto_cipher *tfm = tctx->child;
+	int bs = crypto_shash_blocksize(parent);
+	u8 *odds = PTR_ALIGN(&ctx->ctx[0], alignmask + 1);
+	u8 *prev = odds + bs;
+
+	/* checking the data can fill the block */
+	if ((ctx->len + len) <= bs) {
+		memcpy(odds + ctx->len, p, len);
+		ctx->len += len;
+		return 0;
+	}
+
+	/* filling odds with new data and encrypting it */
+	memcpy(odds + ctx->len, p, bs - ctx->len);
+	len -= bs - ctx->len;
+	p += bs - ctx->len;
+
+	crypto_xor(prev, odds, bs);
+	crypto_cipher_encrypt_one(tfm, prev, prev);
+
+	/* clearing the length */
+	ctx->len = 0;
+
+	/* encrypting the rest of data */
+	while (len > bs) {
+		crypto_xor(prev, p, bs);
+		crypto_cipher_encrypt_one(tfm, prev, prev);
+		p += bs;
+		len -= bs;
+	}
+
+	/* keeping the surplus of blocksize */
+	if (len) {
+		memcpy(odds, p, len);
+		ctx->len = len;
+	}
+
+	return 0;
+}
+
+static int crypto_cmac_digest_final(struct shash_desc *pdesc, u8 *out)
+{
+	struct crypto_shash *parent = pdesc->tfm;
+	unsigned long alignmask = crypto_shash_alignmask(parent);
+	struct cmac_tfm_ctx *tctx = crypto_shash_ctx(parent);
+	struct cmac_desc_ctx *ctx = shash_desc_ctx(pdesc);
+	struct crypto_cipher *tfm = tctx->child;
+	int bs = crypto_shash_blocksize(parent);
+	u8 *consts = PTR_ALIGN(&tctx->ctx[0], alignmask + 1);
+	u8 *odds = PTR_ALIGN(&ctx->ctx[0], alignmask + 1);
+	u8 *prev = odds + bs;
+	unsigned int offset = 0;
+
+	if (ctx->len != bs) {
+		unsigned int rlen;
+		u8 *p = odds + ctx->len;
+
+		*p = 0x80;
+		p++;
+
+		rlen = bs - ctx->len - 1;
+		if (rlen)
+			memset(p, 0, rlen);
+
+		offset += bs;
+	}
+
+	crypto_xor(prev, odds, bs);
+	crypto_xor(prev, consts + offset, bs);
+
+	crypto_cipher_encrypt_one(tfm, out, prev);
+
+	return 0;
+}
+
+static int cmac_init_tfm(struct crypto_tfm *tfm)
+{
+	struct crypto_cipher *cipher;
+	struct crypto_instance *inst = (void *)tfm->__crt_alg;
+	struct crypto_spawn *spawn = crypto_instance_ctx(inst);
+	struct cmac_tfm_ctx *ctx = crypto_tfm_ctx(tfm);
+
+	cipher = crypto_spawn_cipher(spawn);
+	if (IS_ERR(cipher))
+		return PTR_ERR(cipher);
+
+	ctx->child = cipher;
+
+	return 0;
+};
+
+static void cmac_exit_tfm(struct crypto_tfm *tfm)
+{
+	struct cmac_tfm_ctx *ctx = crypto_tfm_ctx(tfm);
+	crypto_free_cipher(ctx->child);
+}
+
+static int cmac_create(struct crypto_template *tmpl, struct rtattr **tb)
+{
+	struct shash_instance *inst;
+	struct crypto_alg *alg;
+	unsigned long alignmask;
+	int err;
+
+	err = crypto_check_attr_type(tb, CRYPTO_ALG_TYPE_SHASH);
+	if (err)
+		return err;
+
+	alg = crypto_get_attr_alg(tb, CRYPTO_ALG_TYPE_CIPHER,
+				  CRYPTO_ALG_TYPE_MASK);
+	if (IS_ERR(alg))
+		return PTR_ERR(alg);
+
+	switch (alg->cra_blocksize) {
+	case 16:
+		break;
+	default:
+		goto out_put_alg;
+	}
+
+	inst = shash_alloc_instance("cmac", alg);
+	err = PTR_ERR(inst);
+	if (IS_ERR(inst))
+		goto out_put_alg;
+
+	err = crypto_init_spawn(shash_instance_ctx(inst), alg,
+				shash_crypto_instance(inst),
+				CRYPTO_ALG_TYPE_MASK);
+	if (err)
+		goto out_free_inst;
+
+	alignmask = alg->cra_alignmask | 3;
+	inst->alg.base.cra_alignmask = alignmask;
+	inst->alg.base.cra_priority = alg->cra_priority;
+	inst->alg.base.cra_blocksize = alg->cra_blocksize;
+
+	inst->alg.digestsize = alg->cra_blocksize;
+	inst->alg.descsize = ALIGN(sizeof(struct cmac_desc_ctx),
+					crypto_tfm_ctx_alignment()) +
+				  (alignmask &
+					~(crypto_tfm_ctx_alignment() - 1)) +
+				  alg->cra_blocksize * 2;
+
+	inst->alg.base.cra_ctxsize = ALIGN(sizeof(struct cmac_tfm_ctx),
+						alignmask + 1) +
+					  alg->cra_blocksize * 2;
+	inst->alg.base.cra_init = cmac_init_tfm;
+	inst->alg.base.cra_exit = cmac_exit_tfm;
+
+	inst->alg.init = crypto_cmac_digest_init;
+	inst->alg.update = crypto_cmac_digest_update;
+	inst->alg.final = crypto_cmac_digest_final;
+	inst->alg.setkey = crypto_cmac_digest_setkey;
+
+	err = shash_register_instance(tmpl, inst);
+	if (err) {
+out_free_inst:
+		shash_free_instance(shash_crypto_instance(inst));
+	}
+
+out_put_alg:
+	crypto_mod_put(alg);
+	return err;
+}
+
+static struct crypto_template crypto_cmac_tmpl = {
+	.name = "cmac",
+	.create = cmac_create,
+	.free = shash_free_instance,
+	.module = THIS_MODULE,
+};
+
+static int __init crypto_cmac_module_init(void)
+{
+	return crypto_register_template(&crypto_cmac_tmpl);
+}
+
+static void __exit crypto_cmac_module_exit(void)
+{
+	crypto_unregister_template(&crypto_cmac_tmpl);
+}
+
+module_init(crypto_cmac_module_init);
+module_exit(crypto_cmac_module_exit);
+
+MODULE_LICENSE("GPL");
+MODULE_DESCRIPTION("CMAC keyed hash algorithm");
diff --git a/crypto/testmgr.c b/crypto/testmgr.c
index edf4a08..6de7994 100644
--- a/crypto/testmgr.c
+++ b/crypto/testmgr.c
@@ -2859,6 +2859,15 @@ static const struct alg_test_desc alg_test_descs[] = {
 			}
 		}
 	}, {
+		.alg = "cmac(aes)",
+		.test = alg_test_hash,
+		.suite = {
+			.hash = {
+				.vecs = aes_cmac128_tv_template,
+				.count = CMAC_AES_TEST_VECTORS
+			}
+		}
+	}, {
 		.alg = "xcbc(aes)",
 		.test = alg_test_hash,
 		.suite = {
diff --git a/crypto/testmgr.h b/crypto/testmgr.h
index b5721e0..9688bfe 100644
--- a/crypto/testmgr.h
+++ b/crypto/testmgr.h
@@ -1639,6 +1639,58 @@ static struct hash_testvec hmac_sha256_tv_template[] = {
 	},
 };
 
+#define CMAC_AES_TEST_VECTORS 4
+
+static struct hash_testvec aes_cmac128_tv_template[] = {
+	{
+		.key  = "\x2b\x7e\x15\x16\x28\xae\xd2\xa6\xab"
+		"\xf7\x15\x88\x09\xcf\x4f\x3c",
+		.plaintext = zeroed_string,
+		.digest = "\xbb\x1d\x69\x29\xe9\x59\x37\x28\x7f"
+		"\xa3\x7d\x12\x9b\x75\x67\x46",
+		.psize   = 0,
+		.ksize   = 16,
+	},
+
+	{
+		.key       = "\x2b\x7e\x15\x16\x28\xae\xd2\xa6\xab\xf7"
+		"\x15\x88\x09\xcf\x4f\x3c",
+		.plaintext = "\x6b\xc1\xbe\xe2\x2e\x40\x9f\x96\xe9\x3d"
+		"\x7e\x11\x73\x93\x17\x2a",
+		.digest    = "\x07\x0a\x16\xb4\x6b\x4d\x41\x44\xf7\x9b"
+		"\xdd\x9d\xd0\x4a\x28\x7c",
+		.psize   = 16,
+		.ksize   = 16,
+	},
+
+	{
+		.key  = "\x2b\x7e\x15\x16\x28\xae\xd2\xa6\xab\xf7"
+		"\x15\x88\x09\xcf\x4f\x3c",
+		.plaintext = "\x6b\xc1\xbe\xe2\x2e\x40\x9f\x96\xe9"
+		"\x3d\x7e\x11\x73\x93\x17"
+		"\x2a\xae\x2d\x8a\x57\x1e\x03\xac\x9c\x9e\xb7\x6f\xac\x45\xaf"
+		"\x8e\x51\x30\xc8\x1c\x46\xa3\x5c\xe4\x11",
+		.digest    = "\xdf\xa6\x67\x47\xde\x9a\xe6\x30\x30\xca\x32"
+		"\x61\x14\x97\xc8\x27",
+		.psize   = 40,
+		.ksize   = 16,
+	},
+	{
+		.key  = "\x2b\x7e\x15\x16\x28\xae\xd2\xa6\xab\xf7"
+		"\x15\x88\x09\xcf\x4f\x3c",
+		.plaintext = "\x6b\xc1\xbe\xe2\x2e\x40\x9f\x96\xe9"
+		"\x3d\x7e\x11\x73\x93\x17"
+		"\x2a\xae\x2d\x8a\x57\x1e\x03\xac\x9c\x9e\xb7\x6f\xac\x45\xaf"
+		"\x8e\x51\x30\xc8\x1c\x46\xa3\x5c\xe4\x11\xe5\xfb\xc1\x19\x1a"
+		"\x0a\x52\xef\xf6\x9f\x24\x45\xdf\x4f\x9b\x17\xad\x2b\x41\x7b"
+		"\xe6\x6c\x37\x10",
+		.digest    = "\x51\xf0\xbe\xbf\x7e\x3b\x9d\x92\xfc\x49\x74"
+		"\x17\x79\x36\x3c\xfe",
+		.psize   = 64,
+		.ksize   = 16,
+	},
+};
+
 #define XCBC_AES_TEST_VECTORS 6
 
 static struct hash_testvec aes_xcbc128_tv_template[] = {
diff --git a/include/uapi/linux/pfkeyv2.h b/include/uapi/linux/pfkeyv2.h
index 0b80c80..d61898e 100644
--- a/include/uapi/linux/pfkeyv2.h
+++ b/include/uapi/linux/pfkeyv2.h
@@ -296,6 +296,7 @@ struct sadb_x_kmaddress {
 #define SADB_X_AALG_SHA2_512HMAC	7
 #define SADB_X_AALG_RIPEMD160HMAC	8
 #define SADB_X_AALG_AES_XCBC_MAC	9
+#define SADB_X_AALG_AES_CMAC_MAC	10
 #define SADB_X_AALG_NULL		251	/* kame */
 #define SADB_AALG_MAX			251
 
diff --git a/net/xfrm/xfrm_algo.c b/net/xfrm/xfrm_algo.c
index 4ce2d93..bd6f227 100644
--- a/net/xfrm/xfrm_algo.c
+++ b/net/xfrm/xfrm_algo.c
@@ -265,6 +265,23 @@ static struct xfrm_algo_desc aalg_list[] = {
 	}
 },
 {
+	.name = "cmac(aes)",
+
+	.uinfo = {
+		.auth = {
+			.icv_truncbits = 96,
+			.icv_fullbits = 128,
+		}
+	},
+
+	.desc = {
+		.sadb_alg_id = SADB_X_AALG_AES_CMAC_MAC,
+		.sadb_alg_ivlen = 0,
+		.sadb_alg_minbits = 128,
+		.sadb_alg_maxbits = 128
+	}
+},
+{
 	.name = "xcbc(aes)",
 
 	.uinfo = {
-- 
1.8.1.rc2.6.g18499ba