arch/s390/crypto/ghash_s390.c

   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
  19 struct ghash_ctx {
  20         u8 key[GHASH_BLOCK_SIZE];
  21 };
  22
  23 struct 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
  30 static 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
  41 static 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
  54 static 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
  92 static 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
 107 static 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
 118 static 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
 135 static 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
 143 static void __exit ghash_mod_exit(void)
 144 {
 145         crypto_unregister_shash(&ghash_alg);
 146 }
 147
 148 module_cpu_feature_match(MSA, ghash_mod_init);
 149 module_exit(ghash_mod_exit);
 150
 151 MODULE_ALIAS_CRYPTO("ghash");
 152
 153 MODULE_LICENSE("GPL");
 154 MODULE_DESCRIPTION("GHASH hash function, s390 implementation");