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authorHuang Ying <ying.huang@intel.com>2009-08-06 15:32:38 +1000
committerHerbert Xu <herbert@gondor.apana.org.au>2009-08-06 15:32:38 +1000
commit2cdc6899a88e2b9c6cb82ebd547bf58932d534df (patch)
tree37b4c093970fe8f5288cef9150f9d03b26c3b92b /crypto/ghash-generic.c
parentcbdcf80d8b9486ddb699a044c6f87f25821708cb (diff)
downloadlinux-2cdc6899a88e2b9c6cb82ebd547bf58932d534df.tar.gz
crypto: ghash - Add GHASH digest algorithm for GCM
GHASH is implemented as a shash algorithm. The actual implementation is copied from gcm.c. This makes it possible to add architecture/hardware accelerated GHASH implementation. Signed-off-by: Huang Ying <ying.huang@intel.com> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Diffstat (limited to 'crypto/ghash-generic.c')
-rw-r--r--crypto/ghash-generic.c170
1 files changed, 170 insertions, 0 deletions
diff --git a/crypto/ghash-generic.c b/crypto/ghash-generic.c
new file mode 100644
index 000000000000..be4425616931
--- /dev/null
+++ b/crypto/ghash-generic.c
@@ -0,0 +1,170 @@
+/*
+ * GHASH: digest algorithm for GCM (Galois/Counter Mode).
+ *
+ * Copyright (c) 2007 Nokia Siemens Networks - Mikko Herranen <mh1@iki.fi>
+ * Copyright (c) 2009 Intel Corp.
+ * Author: Huang Ying <ying.huang@intel.com>
+ *
+ * The algorithm implementation is copied from gcm.c.
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 as published
+ * by the Free Software Foundation.
+ */
+
+#include <crypto/algapi.h>
+#include <crypto/gf128mul.h>
+#include <crypto/internal/hash.h>
+#include <linux/crypto.h>
+#include <linux/init.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+
+#define GHASH_BLOCK_SIZE 16
+#define GHASH_DIGEST_SIZE 16
+
+struct ghash_ctx {
+ struct gf128mul_4k *gf128;
+};
+
+struct ghash_desc_ctx {
+ u8 buffer[GHASH_BLOCK_SIZE];
+ u32 bytes;
+};
+
+static int ghash_init(struct shash_desc *desc)
+{
+ struct ghash_desc_ctx *dctx = shash_desc_ctx(desc);
+
+ memset(dctx, 0, sizeof(*dctx));
+
+ return 0;
+}
+
+static int ghash_setkey(struct crypto_shash *tfm,
+ const u8 *key, unsigned int keylen)
+{
+ struct ghash_ctx *ctx = crypto_shash_ctx(tfm);
+
+ if (keylen != GHASH_BLOCK_SIZE) {
+ crypto_shash_set_flags(tfm, CRYPTO_TFM_RES_BAD_KEY_LEN);
+ return -EINVAL;
+ }
+
+ if (ctx->gf128)
+ gf128mul_free_4k(ctx->gf128);
+ ctx->gf128 = gf128mul_init_4k_lle((be128 *)key);
+ if (!ctx->gf128)
+ return -ENOMEM;
+
+ return 0;
+}
+
+static int ghash_update(struct shash_desc *desc,
+ const u8 *src, unsigned int srclen)
+{
+ struct ghash_desc_ctx *dctx = shash_desc_ctx(desc);
+ struct ghash_ctx *ctx = crypto_shash_ctx(desc->tfm);
+ u8 *dst = dctx->buffer;
+
+ if (dctx->bytes) {
+ int n = min(srclen, dctx->bytes);
+ u8 *pos = dst + (GHASH_BLOCK_SIZE - dctx->bytes);
+
+ dctx->bytes -= n;
+ srclen -= n;
+
+ while (n--)
+ *pos++ ^= *src++;
+
+ if (!dctx->bytes)
+ gf128mul_4k_lle((be128 *)dst, ctx->gf128);
+ }
+
+ while (srclen >= GHASH_BLOCK_SIZE) {
+ crypto_xor(dst, src, GHASH_BLOCK_SIZE);
+ gf128mul_4k_lle((be128 *)dst, ctx->gf128);
+ src += GHASH_BLOCK_SIZE;
+ srclen -= GHASH_BLOCK_SIZE;
+ }
+
+ if (srclen) {
+ dctx->bytes = GHASH_BLOCK_SIZE - srclen;
+ while (srclen--)
+ *dst++ ^= *src++;
+ }
+
+ return 0;
+}
+
+static void ghash_flush(struct ghash_ctx *ctx, struct ghash_desc_ctx *dctx)
+{
+ u8 *dst = dctx->buffer;
+
+ if (dctx->bytes) {
+ u8 *tmp = dst + (GHASH_BLOCK_SIZE - dctx->bytes);
+
+ while (dctx->bytes--)
+ *tmp++ ^= 0;
+
+ gf128mul_4k_lle((be128 *)dst, ctx->gf128);
+ }
+
+ dctx->bytes = 0;
+}
+
+static int ghash_final(struct shash_desc *desc, u8 *dst)
+{
+ struct ghash_desc_ctx *dctx = shash_desc_ctx(desc);
+ struct ghash_ctx *ctx = crypto_shash_ctx(desc->tfm);
+ u8 *buf = dctx->buffer;
+
+ ghash_flush(ctx, dctx);
+ memcpy(dst, buf, GHASH_BLOCK_SIZE);
+
+ return 0;
+}
+
+static void ghash_exit_tfm(struct crypto_tfm *tfm)
+{
+ struct ghash_ctx *ctx = crypto_tfm_ctx(tfm);
+ if (ctx->gf128)
+ gf128mul_free_4k(ctx->gf128);
+}
+
+static struct shash_alg ghash_alg = {
+ .digestsize = GHASH_DIGEST_SIZE,
+ .init = ghash_init,
+ .update = ghash_update,
+ .final = ghash_final,
+ .setkey = ghash_setkey,
+ .descsize = sizeof(struct ghash_desc_ctx),
+ .base = {
+ .cra_name = "ghash",
+ .cra_driver_name = "ghash-generic",
+ .cra_priority = 100,
+ .cra_flags = CRYPTO_ALG_TYPE_SHASH,
+ .cra_blocksize = GHASH_BLOCK_SIZE,
+ .cra_ctxsize = sizeof(struct ghash_ctx),
+ .cra_module = THIS_MODULE,
+ .cra_list = LIST_HEAD_INIT(ghash_alg.base.cra_list),
+ .cra_exit = ghash_exit_tfm,
+ },
+};
+
+static int __init ghash_mod_init(void)
+{
+ return crypto_register_shash(&ghash_alg);
+}
+
+static void __exit ghash_mod_exit(void)
+{
+ crypto_unregister_shash(&ghash_alg);
+}
+
+module_init(ghash_mod_init);
+module_exit(ghash_mod_exit);
+
+MODULE_LICENSE("GPL");
+MODULE_DESCRIPTION("GHASH Message Digest Algorithm");
+MODULE_ALIAS("ghash");