mac80211: use AES_BLOCK_SIZE
[linux-2.6/linux-acpi-2.6/ibm-acpi-2.6.git] / crypto / ghash-generic.c
blobbe4425616931ffcf0f1747aa752d76f15379c989
1 /*
2 * GHASH: digest algorithm for GCM (Galois/Counter Mode).
4 * Copyright (c) 2007 Nokia Siemens Networks - Mikko Herranen <mh1@iki.fi>
5 * Copyright (c) 2009 Intel Corp.
6 * Author: Huang Ying <ying.huang@intel.com>
8 * The algorithm implementation is copied from gcm.c.
10 * This program is free software; you can redistribute it and/or modify it
11 * under the terms of the GNU General Public License version 2 as published
12 * by the Free Software Foundation.
15 #include <crypto/algapi.h>
16 #include <crypto/gf128mul.h>
17 #include <crypto/internal/hash.h>
18 #include <linux/crypto.h>
19 #include <linux/init.h>
20 #include <linux/kernel.h>
21 #include <linux/module.h>
23 #define GHASH_BLOCK_SIZE 16
24 #define GHASH_DIGEST_SIZE 16
26 struct ghash_ctx {
27 struct gf128mul_4k *gf128;
30 struct ghash_desc_ctx {
31 u8 buffer[GHASH_BLOCK_SIZE];
32 u32 bytes;
35 static int ghash_init(struct shash_desc *desc)
37 struct ghash_desc_ctx *dctx = shash_desc_ctx(desc);
39 memset(dctx, 0, sizeof(*dctx));
41 return 0;
44 static int ghash_setkey(struct crypto_shash *tfm,
45 const u8 *key, unsigned int keylen)
47 struct ghash_ctx *ctx = crypto_shash_ctx(tfm);
49 if (keylen != GHASH_BLOCK_SIZE) {
50 crypto_shash_set_flags(tfm, CRYPTO_TFM_RES_BAD_KEY_LEN);
51 return -EINVAL;
54 if (ctx->gf128)
55 gf128mul_free_4k(ctx->gf128);
56 ctx->gf128 = gf128mul_init_4k_lle((be128 *)key);
57 if (!ctx->gf128)
58 return -ENOMEM;
60 return 0;
63 static int ghash_update(struct shash_desc *desc,
64 const u8 *src, unsigned int srclen)
66 struct ghash_desc_ctx *dctx = shash_desc_ctx(desc);
67 struct ghash_ctx *ctx = crypto_shash_ctx(desc->tfm);
68 u8 *dst = dctx->buffer;
70 if (dctx->bytes) {
71 int n = min(srclen, dctx->bytes);
72 u8 *pos = dst + (GHASH_BLOCK_SIZE - dctx->bytes);
74 dctx->bytes -= n;
75 srclen -= n;
77 while (n--)
78 *pos++ ^= *src++;
80 if (!dctx->bytes)
81 gf128mul_4k_lle((be128 *)dst, ctx->gf128);
84 while (srclen >= GHASH_BLOCK_SIZE) {
85 crypto_xor(dst, src, GHASH_BLOCK_SIZE);
86 gf128mul_4k_lle((be128 *)dst, ctx->gf128);
87 src += GHASH_BLOCK_SIZE;
88 srclen -= GHASH_BLOCK_SIZE;
91 if (srclen) {
92 dctx->bytes = GHASH_BLOCK_SIZE - srclen;
93 while (srclen--)
94 *dst++ ^= *src++;
97 return 0;
100 static void ghash_flush(struct ghash_ctx *ctx, struct ghash_desc_ctx *dctx)
102 u8 *dst = dctx->buffer;
104 if (dctx->bytes) {
105 u8 *tmp = dst + (GHASH_BLOCK_SIZE - dctx->bytes);
107 while (dctx->bytes--)
108 *tmp++ ^= 0;
110 gf128mul_4k_lle((be128 *)dst, ctx->gf128);
113 dctx->bytes = 0;
116 static int ghash_final(struct shash_desc *desc, u8 *dst)
118 struct ghash_desc_ctx *dctx = shash_desc_ctx(desc);
119 struct ghash_ctx *ctx = crypto_shash_ctx(desc->tfm);
120 u8 *buf = dctx->buffer;
122 ghash_flush(ctx, dctx);
123 memcpy(dst, buf, GHASH_BLOCK_SIZE);
125 return 0;
128 static void ghash_exit_tfm(struct crypto_tfm *tfm)
130 struct ghash_ctx *ctx = crypto_tfm_ctx(tfm);
131 if (ctx->gf128)
132 gf128mul_free_4k(ctx->gf128);
135 static struct shash_alg ghash_alg = {
136 .digestsize = GHASH_DIGEST_SIZE,
137 .init = ghash_init,
138 .update = ghash_update,
139 .final = ghash_final,
140 .setkey = ghash_setkey,
141 .descsize = sizeof(struct ghash_desc_ctx),
142 .base = {
143 .cra_name = "ghash",
144 .cra_driver_name = "ghash-generic",
145 .cra_priority = 100,
146 .cra_flags = CRYPTO_ALG_TYPE_SHASH,
147 .cra_blocksize = GHASH_BLOCK_SIZE,
148 .cra_ctxsize = sizeof(struct ghash_ctx),
149 .cra_module = THIS_MODULE,
150 .cra_list = LIST_HEAD_INIT(ghash_alg.base.cra_list),
151 .cra_exit = ghash_exit_tfm,
155 static int __init ghash_mod_init(void)
157 return crypto_register_shash(&ghash_alg);
160 static void __exit ghash_mod_exit(void)
162 crypto_unregister_shash(&ghash_alg);
165 module_init(ghash_mod_init);
166 module_exit(ghash_mod_exit);
168 MODULE_LICENSE("GPL");
169 MODULE_DESCRIPTION("GHASH Message Digest Algorithm");
170 MODULE_ALIAS("ghash");