LXR linux/arch/s390/crypto/ghash

   1// SPDX-License-Identifier: GPL-2.0
   2/*
   3 * Cryptographic API.
   4 *
   5 * s390 implementation of the GHASH algorithm for GCM (Galois/Counter Mode).
   6 *
   7 * Copyright IBM Corp. 2011
   8 * Author(s): Gerald Schaefer <gerald.schaefer@de.ibm.com>
   9 */
  10
  11#include <crypto/internal/hash.h>
  12#include <linux/module.h>
  13#include <linux/cpufeature.h>
  14#include <asm/cpacf.h>
  15
  16#define GHASH_BLOCK_SIZE        16
  17#define GHASH_DIGEST_SIZE       16
  18
  19struct ghash_ctx {
  20        u8 key[GHASH_BLOCK_SIZE];
  21};
  22
  23struct ghash_desc_ctx {
  24        u8 icv[GHASH_BLOCK_SIZE];
  25        u8 key[GHASH_BLOCK_SIZE];
  26        u8 buffer[GHASH_BLOCK_SIZE];
  27        u32 bytes;
  28};
  29
  30static int ghash_init(struct shash_desc *desc)
  31{
  32        struct ghash_desc_ctx *dctx = shash_desc_ctx(desc);
  33        struct ghash_ctx *ctx = crypto_shash_ctx(desc->tfm);
  34
  35        memset(dctx, 0, sizeof(*dctx));
  36        memcpy(dctx->key, ctx->key, GHASH_BLOCK_SIZE);
  37
  38        return 0;
  39}
  40
  41static int ghash_setkey(struct crypto_shash *tfm,
  42                        const u8 *key, unsigned int keylen)
  43{
  44        struct ghash_ctx *ctx = crypto_shash_ctx(tfm);
  45
  46        if (keylen != GHASH_BLOCK_SIZE)
  47                return -EINVAL;
  48
  49        memcpy(ctx->key, key, GHASH_BLOCK_SIZE);
  50
  51        return 0;
  52}
  53
  54static int ghash_update(struct shash_desc *desc,
  55                         const u8 *src, unsigned int srclen)
  56{
  57        struct ghash_desc_ctx *dctx = shash_desc_ctx(desc);
  58        unsigned int n;
  59        u8 *buf = dctx->buffer;
  60
  61        if (dctx->bytes) {
  62                u8 *pos = buf + (GHASH_BLOCK_SIZE - dctx->bytes);
  63
  64                n = min(srclen, dctx->bytes);
  65                dctx->bytes -= n;
  66                srclen -= n;
  67
  68                memcpy(pos, src, n);
  69                src += n;
  70
  71                if (!dctx->bytes) {
  72                        cpacf_kimd(CPACF_KIMD_GHASH, dctx, buf,
  73                                   GHASH_BLOCK_SIZE);
  74                }
  75        }
  76
  77        n = srclen & ~(GHASH_BLOCK_SIZE - 1);
  78        if (n) {
  79                cpacf_kimd(CPACF_KIMD_GHASH, dctx, src, n);
  80                src += n;
  81                srclen -= n;
  82        }
  83
  84        if (srclen) {
  85                dctx->bytes = GHASH_BLOCK_SIZE - srclen;
  86                memcpy(buf, src, srclen);
  87        }
  88
  89        return 0;
  90}
  91
  92static int ghash_flush(struct ghash_desc_ctx *dctx)
  93{
  94        u8 *buf = dctx->buffer;
  95
  96        if (dctx->bytes) {
  97                u8 *pos = buf + (GHASH_BLOCK_SIZE - dctx->bytes);
  98
  99                memset(pos, 0, dctx->bytes);
 100                cpacf_kimd(CPACF_KIMD_GHASH, dctx, buf, GHASH_BLOCK_SIZE);
 101                dctx->bytes = 0;
 102        }
 103
 104        return 0;
 105}
 106
 107static int ghash_final(struct shash_desc *desc, u8 *dst)
 108{
 109        struct ghash_desc_ctx *dctx = shash_desc_ctx(desc);
 110        int ret;
 111
 112        ret = ghash_flush(dctx);
 113        if (!ret)
 114                memcpy(dst, dctx->icv, GHASH_BLOCK_SIZE);
 115        return ret;
 116}
 117
 118static struct shash_alg ghash_alg = {
 119        .digestsize     = GHASH_DIGEST_SIZE,
 120        .init           = ghash_init,
 121        .update         = ghash_update,
 122        .final          = ghash_final,
 123        .setkey         = ghash_setkey,
 124        .descsize       = sizeof(struct ghash_desc_ctx),
 125        .base           = {
 126                .cra_name               = "ghash",
 127                .cra_driver_name        = "ghash-s390",
 128                .cra_priority           = 300,
 129                .cra_blocksize          = GHASH_BLOCK_SIZE,
 130                .cra_ctxsize            = sizeof(struct ghash_ctx),
 131                .cra_module             = THIS_MODULE,
 132        },
 133};
 134
 135static int __init ghash_mod_init(void)
 136{
 137        if (!cpacf_query_func(CPACF_KIMD, CPACF_KIMD_GHASH))
 138                return -ENODEV;
 139
 140        return crypto_register_shash(&ghash_alg);
 141}
 142
 143static void __exit ghash_mod_exit(void)
 144{
 145        crypto_unregister_shash(&ghash_alg);
 146}
 147
 148module_cpu_feature_match(MSA, ghash_mod_init);
 149module_exit(ghash_mod_exit);
 150
 151MODULE_ALIAS_CRYPTO("ghash");
 152
 153MODULE_LICENSE("GPL");
 154MODULE_DESCRIPTION("GHASH hash function, s390 implementation");
 155