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/*
* Cryptographic API.
*
* s390 implementation of the GHASH algorithm for GCM (Galois/Counter Mode).
*
* Copyright IBM Corp. 2011
* Author(s): Gerald Schaefer <gerald.schaefer@de.ibm.com>
*/
#include <crypto/internal/hash.h>
#include <linux/module.h>
#include "crypt_s390.h"
#define GHASH_BLOCK_SIZE 16
#define GHASH_DIGEST_SIZE 16
struct ghash_ctx {
u8 icv[16];
u8 key[16];
};
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;
}
memcpy(ctx->key, key, GHASH_BLOCK_SIZE);
memset(ctx->icv, 0, GHASH_BLOCK_SIZE);
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);
unsigned int n;
u8 *buf = dctx->buffer;
int ret;
if (dctx->bytes) {
u8 *pos = buf + (GHASH_BLOCK_SIZE - dctx->bytes);
n = min(srclen, dctx->bytes);
dctx->bytes -= n;
srclen -= n;
memcpy(pos, src, n);
src += n;
if (!dctx->bytes) {
ret = crypt_s390_kimd(KIMD_GHASH, ctx, buf,
GHASH_BLOCK_SIZE);
if (ret != GHASH_BLOCK_SIZE)
return -EIO;
}
}
n = srclen & ~(GHASH_BLOCK_SIZE - 1);
if (n) {
ret = crypt_s390_kimd(KIMD_GHASH, ctx, src, n);
if (ret != n)
return -EIO;
src += n;
srclen -= n;
}
if (srclen) {
dctx->bytes = GHASH_BLOCK_SIZE - srclen;
memcpy(buf, src, srclen);
}
return 0;
}
static int ghash_flush(struct ghash_ctx *ctx, struct ghash_desc_ctx *dctx)
{
u8 *buf = dctx->buffer;
int ret;
if (dctx->bytes) {
u8 *pos = buf + (GHASH_BLOCK_SIZE - dctx->bytes);
memset(pos, 0, dctx->bytes);
ret = crypt_s390_kimd(KIMD_GHASH, ctx, buf, GHASH_BLOCK_SIZE);
if (ret != GHASH_BLOCK_SIZE)
return -EIO;
}
dctx->bytes = 0;
return 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);
int ret;
ret = ghash_flush(ctx, dctx);
if (!ret)
memcpy(dst, ctx->icv, GHASH_BLOCK_SIZE);
return ret;
}
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-s390",
.cra_priority = CRYPT_S390_PRIORITY,
.cra_flags = CRYPTO_ALG_TYPE_SHASH,
.cra_blocksize = GHASH_BLOCK_SIZE,
.cra_ctxsize = sizeof(struct ghash_ctx),
.cra_module = THIS_MODULE,
},
};
static int __init ghash_mod_init(void)
{
if (!crypt_s390_func_available(KIMD_GHASH,
CRYPT_S390_MSA | CRYPT_S390_MSA4))
return -EOPNOTSUPP;
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_ALIAS("ghash");
MODULE_LICENSE("GPL");
MODULE_DESCRIPTION("GHASH Message Digest Algorithm, s390 implementation");
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