diff options
Diffstat (limited to 'crypto/ghash-generic.c')
| -rw-r--r-- | crypto/ghash-generic.c | 170 |
1 files changed, 170 insertions, 0 deletions
diff --git a/crypto/ghash-generic.c b/crypto/ghash-generic.c new file mode 100644 index 00000000..be442561 --- /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"); |