[CRYPTO] xcbc: New algorithm
This is core code of XCBC.
XCBC is an algorithm that forms a MAC algorithm out of a cipher algorithm.
For example, AES-XCBC-MAC is a MAC algorithm based on the AES cipher
algorithm.
Signed-off-by: Kazunori MIYAZAWA <miyazawa@linux-ipv6.org>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
diff --git a/crypto/Kconfig b/crypto/Kconfig
index cbae839..4495e46 100644
--- a/crypto/Kconfig
+++ b/crypto/Kconfig
@@ -39,6 +39,17 @@
HMAC: Keyed-Hashing for Message Authentication (RFC2104).
This is required for IPSec.
+config CRYPTO_XCBC
+ tristate "XCBC support"
+ depends on EXPERIMENTAL
+ select CRYPTO_HASH
+ select CRYPTO_MANAGER
+ help
+ XCBC: Keyed-Hashing with encryption algorithm
+ http://www.ietf.org/rfc/rfc3566.txt
+ http://csrc.nist.gov/encryption/modes/proposedmodes/
+ xcbc-mac/xcbc-mac-spec.pdf
+
config CRYPTO_NULL
tristate "Null algorithms"
select CRYPTO_ALGAPI
diff --git a/crypto/Makefile b/crypto/Makefile
index 7236620..aba9625 100644
--- a/crypto/Makefile
+++ b/crypto/Makefile
@@ -15,6 +15,7 @@
obj-$(CONFIG_CRYPTO_MANAGER) += cryptomgr.o
obj-$(CONFIG_CRYPTO_HMAC) += hmac.o
+obj-$(CONFIG_CRYPTO_XCBC) += xcbc.o
obj-$(CONFIG_CRYPTO_NULL) += crypto_null.o
obj-$(CONFIG_CRYPTO_MD4) += md4.o
obj-$(CONFIG_CRYPTO_MD5) += md5.o
diff --git a/crypto/xcbc.c b/crypto/xcbc.c
new file mode 100644
index 0000000..f592950
--- /dev/null
+++ b/crypto/xcbc.c
@@ -0,0 +1,346 @@
+/*
+ * 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:
+ * Kazunori Miyazawa <miyazawa@linux-ipv6.org>
+ */
+
+#include <linux/crypto.h>
+#include <linux/err.h>
+#include <linux/kernel.h>
+#include <linux/mm.h>
+#include <linux/rtnetlink.h>
+#include <linux/slab.h>
+#include <linux/scatterlist.h>
+#include "internal.h"
+
+u_int32_t ks[12] = {0x01010101, 0x01010101, 0x01010101, 0x01010101,
+ 0x02020202, 0x02020202, 0x02020202, 0x02020202,
+ 0x03030303, 0x03030303, 0x03030303, 0x03030303};
+/*
+ * +------------------------
+ * | <parent tfm>
+ * +------------------------
+ * | crypto_xcbc_ctx
+ * +------------------------
+ * | odds (block size)
+ * +------------------------
+ * | prev (block size)
+ * +------------------------
+ * | key (block size)
+ * +------------------------
+ * | consts (block size * 3)
+ * +------------------------
+ */
+struct crypto_xcbc_ctx {
+ struct crypto_tfm *child;
+ u8 *odds;
+ u8 *prev;
+ u8 *key;
+ u8 *consts;
+ void (*xor)(u8 *a, const u8 *b, unsigned int bs);
+ unsigned int keylen;
+ unsigned int len;
+};
+
+static void xor_128(u8 *a, const u8 *b, unsigned int bs)
+{
+ ((u32 *)a)[0] ^= ((u32 *)b)[0];
+ ((u32 *)a)[1] ^= ((u32 *)b)[1];
+ ((u32 *)a)[2] ^= ((u32 *)b)[2];
+ ((u32 *)a)[3] ^= ((u32 *)b)[3];
+}
+
+static int _crypto_xcbc_digest_setkey(struct crypto_hash *parent,
+ struct crypto_xcbc_ctx *ctx)
+{
+ int bs = crypto_hash_blocksize(parent);
+ int err = 0;
+ u8 key1[bs];
+
+ if ((err = crypto_cipher_setkey(ctx->child, ctx->key, ctx->keylen)))
+ return err;
+
+ ctx->child->__crt_alg->cra_cipher.cia_encrypt(ctx->child, key1,
+ ctx->consts);
+
+ return crypto_cipher_setkey(ctx->child, key1, bs);
+}
+
+static int crypto_xcbc_digest_setkey(struct crypto_hash *parent,
+ const u8 *inkey, unsigned int keylen)
+{
+ struct crypto_xcbc_ctx *ctx = crypto_hash_ctx_aligned(parent);
+
+ if (keylen != crypto_tfm_alg_blocksize(ctx->child))
+ return -EINVAL;
+
+ ctx->keylen = keylen;
+ memcpy(ctx->key, inkey, keylen);
+ ctx->consts = (u8*)ks;
+
+ return _crypto_xcbc_digest_setkey(parent, ctx);
+}
+
+int crypto_xcbc_digest_init(struct hash_desc *pdesc)
+{
+ struct crypto_xcbc_ctx *ctx = crypto_hash_ctx_aligned(pdesc->tfm);
+ int bs = crypto_hash_blocksize(pdesc->tfm);
+
+ ctx->len = 0;
+ memset(ctx->odds, 0, bs);
+ memset(ctx->prev, 0, bs);
+
+ return 0;
+}
+
+int crypto_xcbc_digest_update(struct hash_desc *pdesc, struct scatterlist *sg, unsigned int nbytes)
+{
+ struct crypto_hash *parent = pdesc->tfm;
+ struct crypto_xcbc_ctx *ctx = crypto_hash_ctx_aligned(parent);
+ struct crypto_tfm *tfm = ctx->child;
+ int bs = crypto_hash_blocksize(parent);
+ unsigned int i = 0;
+
+ do {
+
+ struct page *pg = sg[i].page;
+ unsigned int offset = sg[i].offset;
+ unsigned int slen = sg[i].length;
+
+ while (slen > 0) {
+ unsigned int len = min(slen, ((unsigned int)(PAGE_SIZE)) - offset);
+ char *p = crypto_kmap(pg, 0) + offset;
+
+ /* checking the data can fill the block */
+ if ((ctx->len + len) <= bs) {
+ memcpy(ctx->odds + ctx->len, p, len);
+ ctx->len += len;
+ slen -= len;
+
+ /* checking the rest of the page */
+ if (len + offset >= PAGE_SIZE) {
+ offset = 0;
+ pg++;
+ } else
+ offset += len;
+
+ crypto_kunmap(p, 0);
+ crypto_yield(tfm->crt_flags);
+ continue;
+ }
+
+ /* filling odds with new data and encrypting it */
+ memcpy(ctx->odds + ctx->len, p, bs - ctx->len);
+ len -= bs - ctx->len;
+ p += bs - ctx->len;
+
+ ctx->xor(ctx->prev, ctx->odds, bs);
+ tfm->__crt_alg->cra_cipher.cia_encrypt(tfm, ctx->prev, ctx->prev);
+
+ /* clearing the length */
+ ctx->len = 0;
+
+ /* encrypting the rest of data */
+ while (len > bs) {
+ ctx->xor(ctx->prev, p, bs);
+ tfm->__crt_alg->cra_cipher.cia_encrypt(tfm, ctx->prev, ctx->prev);
+ p += bs;
+ len -= bs;
+ }
+
+ /* keeping the surplus of blocksize */
+ if (len) {
+ memcpy(ctx->odds, p, len);
+ ctx->len = len;
+ }
+ crypto_kunmap(p, 0);
+ crypto_yield(tfm->crt_flags);
+ slen -= min(slen, ((unsigned int)(PAGE_SIZE)) - offset);
+ offset = 0;
+ pg++;
+ }
+ nbytes-=sg[i].length;
+ i++;
+ } while (nbytes>0);
+
+ return 0;
+}
+
+int crypto_xcbc_digest_final(struct hash_desc *pdesc, u8 *out)
+{
+ struct crypto_hash *parent = pdesc->tfm;
+ struct crypto_xcbc_ctx *ctx = crypto_hash_ctx_aligned(parent);
+ struct crypto_tfm *tfm = ctx->child;
+ int bs = crypto_hash_blocksize(parent);
+ int err = 0;
+
+ if (ctx->len == bs) {
+ u8 key2[bs];
+
+ if ((err = crypto_cipher_setkey(tfm, ctx->key, ctx->keylen)) != 0)
+ return err;
+
+ tfm->__crt_alg->cra_cipher.cia_encrypt(tfm, key2, (const u8*)(ctx->consts+bs));
+
+ ctx->xor(ctx->prev, ctx->odds, bs);
+ ctx->xor(ctx->prev, key2, bs);
+ _crypto_xcbc_digest_setkey(parent, ctx);
+
+ tfm->__crt_alg->cra_cipher.cia_encrypt(tfm, out, ctx->prev);
+ } else {
+ u8 key3[bs];
+ unsigned int rlen;
+ u8 *p = ctx->odds + ctx->len;
+ *p = 0x80;
+ p++;
+
+ rlen = bs - ctx->len -1;
+ if (rlen)
+ memset(p, 0, rlen);
+
+ if ((err = crypto_cipher_setkey(tfm, ctx->key, ctx->keylen)) != 0)
+ return err;
+
+ tfm->__crt_alg->cra_cipher.cia_encrypt(tfm, key3, (const u8*)(ctx->consts+bs*2));
+
+ ctx->xor(ctx->prev, ctx->odds, bs);
+ ctx->xor(ctx->prev, key3, bs);
+
+ _crypto_xcbc_digest_setkey(parent, ctx);
+
+ tfm->__crt_alg->cra_cipher.cia_encrypt(tfm, out, ctx->prev);
+ }
+
+ return 0;
+}
+
+static int crypto_xcbc_digest(struct hash_desc *pdesc,
+ struct scatterlist *sg, unsigned int nbytes, u8 *out)
+{
+ crypto_xcbc_digest_init(pdesc);
+ crypto_xcbc_digest_update(pdesc, sg, nbytes);
+ return crypto_xcbc_digest_final(pdesc, out);
+}
+
+static int xcbc_init_tfm(struct crypto_tfm *tfm)
+{
+ struct crypto_instance *inst = (void *)tfm->__crt_alg;
+ struct crypto_spawn *spawn = crypto_instance_ctx(inst);
+ struct crypto_xcbc_ctx *ctx = crypto_hash_ctx_aligned(__crypto_hash_cast(tfm));
+ int bs = crypto_hash_blocksize(__crypto_hash_cast(tfm));
+
+ tfm = crypto_spawn_tfm(spawn);
+ if (IS_ERR(tfm))
+ return PTR_ERR(tfm);
+
+ switch(bs) {
+ case 16:
+ ctx->xor = xor_128;
+ break;
+ default:
+ return -EINVAL;
+ }
+
+ ctx->child = crypto_cipher_cast(tfm);
+ ctx->odds = (u8*)(ctx+1);
+ ctx->prev = ctx->odds + bs;
+ ctx->key = ctx->prev + bs;
+
+ return 0;
+};
+
+static void xcbc_exit_tfm(struct crypto_tfm *tfm)
+{
+ struct crypto_xcbc_ctx *ctx = crypto_hash_ctx_aligned(__crypto_hash_cast(tfm));
+ crypto_free_cipher(ctx->child);
+}
+
+static struct crypto_instance *xcbc_alloc(void *param, unsigned int len)
+{
+ struct crypto_instance *inst;
+ struct crypto_alg *alg;
+ alg = crypto_get_attr_alg(param, len, CRYPTO_ALG_TYPE_CIPHER,
+ CRYPTO_ALG_TYPE_HASH_MASK | CRYPTO_ALG_ASYNC);
+ if (IS_ERR(alg))
+ return ERR_PTR(PTR_ERR(alg));
+
+ switch(alg->cra_blocksize) {
+ case 16:
+ break;
+ default:
+ return ERR_PTR(PTR_ERR(alg));
+ }
+
+ inst = crypto_alloc_instance("xcbc", alg);
+ if (IS_ERR(inst))
+ goto out_put_alg;
+
+ inst->alg.cra_flags = CRYPTO_ALG_TYPE_HASH;
+ inst->alg.cra_priority = alg->cra_priority;
+ inst->alg.cra_blocksize = alg->cra_blocksize;
+ inst->alg.cra_alignmask = alg->cra_alignmask;
+ inst->alg.cra_type = &crypto_hash_type;
+
+ inst->alg.cra_hash.digestsize =
+ (alg->cra_flags & CRYPTO_ALG_TYPE_MASK) ==
+ CRYPTO_ALG_TYPE_HASH ? alg->cra_hash.digestsize :
+ alg->cra_blocksize;
+ inst->alg.cra_ctxsize = sizeof(struct crypto_xcbc_ctx) +
+ ALIGN(inst->alg.cra_blocksize * 3, sizeof(void *));
+ inst->alg.cra_init = xcbc_init_tfm;
+ inst->alg.cra_exit = xcbc_exit_tfm;
+
+ inst->alg.cra_hash.init = crypto_xcbc_digest_init;
+ inst->alg.cra_hash.update = crypto_xcbc_digest_update;
+ inst->alg.cra_hash.final = crypto_xcbc_digest_final;
+ inst->alg.cra_hash.digest = crypto_xcbc_digest;
+ inst->alg.cra_hash.setkey = crypto_xcbc_digest_setkey;
+
+out_put_alg:
+ crypto_mod_put(alg);
+ return inst;
+}
+
+static void xcbc_free(struct crypto_instance *inst)
+{
+ crypto_drop_spawn(crypto_instance_ctx(inst));
+ kfree(inst);
+}
+
+static struct crypto_template crypto_xcbc_tmpl = {
+ .name = "xcbc",
+ .alloc = xcbc_alloc,
+ .free = xcbc_free,
+ .module = THIS_MODULE,
+};
+
+static int __init crypto_xcbc_module_init(void)
+{
+ return crypto_register_template(&crypto_xcbc_tmpl);
+}
+
+static void __exit crypto_xcbc_module_exit(void)
+{
+ crypto_unregister_template(&crypto_xcbc_tmpl);
+}
+
+module_init(crypto_xcbc_module_init);
+module_exit(crypto_xcbc_module_exit);
+
+MODULE_LICENSE("GPL");
+MODULE_DESCRIPTION("XCBC keyed hash algorithm");