/* * 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/ghash.h> #include <crypto/internal/hash.h> #include <linux/crypto.h> #include <linux/init.h> #include <linux/kernel.h> #include <linux/module.h> 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 (!ctx->gf128) return -ENOKEY; 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; if (!ctx->gf128) return -ENOKEY; 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_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_CRYPTO("ghash"); MODULE_ALIAS_CRYPTO("ghash-generic");