s390/crypto/ghash_s390.c

0001 // SPDX-License-Identifier: GPL-2.0
0002 /*
0003  * Cryptographic API.
0004  *
0005  * s390 implementation of the GHASH algorithm for GCM (Galois/Counter Mode).
0006  *
0007  * Copyright IBM Corp. 2011
0008  * Author(s): Gerald Schaefer <gerald.schaefer@de.ibm.com>
0009  */
0010
0011 #include <crypto/internal/hash.h>
0012 #include <linux/module.h>
0013 #include <linux/cpufeature.h>
0014 #include <asm/cpacf.h>
0015
0016 #define GHASH_BLOCK_SIZE    16
0017 #define GHASH_DIGEST_SIZE   16
0018
0019 struct ghash_ctx {
0020     u8 key[GHASH_BLOCK_SIZE];
0021 };
0022
0023 struct ghash_desc_ctx {
0024     u8 icv[GHASH_BLOCK_SIZE];
0025     u8 key[GHASH_BLOCK_SIZE];
0026     u8 buffer[GHASH_BLOCK_SIZE];
0027     u32 bytes;
0028 };
0029
0030 static int ghash_init(struct shash_desc *desc)
0031 {
0032     struct ghash_desc_ctx *dctx = shash_desc_ctx(desc);
0033     struct ghash_ctx *ctx = crypto_shash_ctx(desc->tfm);
0034
0035     memset(dctx, 0, sizeof(*dctx));
0036     memcpy(dctx->key, ctx->key, GHASH_BLOCK_SIZE);
0037
0038     return 0;
0039 }
0040
0041 static int ghash_setkey(struct crypto_shash *tfm,
0042             const u8 *key, unsigned int keylen)
0043 {
0044     struct ghash_ctx *ctx = crypto_shash_ctx(tfm);
0045
0046     if (keylen != GHASH_BLOCK_SIZE)
0047         return -EINVAL;
0048
0049     memcpy(ctx->key, key, GHASH_BLOCK_SIZE);
0050
0051     return 0;
0052 }
0053
0054 static int ghash_update(struct shash_desc *desc,
0055              const u8 *src, unsigned int srclen)
0056 {
0057     struct ghash_desc_ctx *dctx = shash_desc_ctx(desc);
0058     unsigned int n;
0059     u8 *buf = dctx->buffer;
0060
0061     if (dctx->bytes) {
0062         u8 *pos = buf + (GHASH_BLOCK_SIZE - dctx->bytes);
0063
0064         n = min(srclen, dctx->bytes);
0065         dctx->bytes -= n;
0066         srclen -= n;
0067
0068         memcpy(pos, src, n);
0069         src += n;
0070
0071         if (!dctx->bytes) {
0072             cpacf_kimd(CPACF_KIMD_GHASH, dctx, buf,
0073                    GHASH_BLOCK_SIZE);
0074         }
0075     }
0076
0077     n = srclen & ~(GHASH_BLOCK_SIZE - 1);
0078     if (n) {
0079         cpacf_kimd(CPACF_KIMD_GHASH, dctx, src, n);
0080         src += n;
0081         srclen -= n;
0082     }
0083
0084     if (srclen) {
0085         dctx->bytes = GHASH_BLOCK_SIZE - srclen;
0086         memcpy(buf, src, srclen);
0087     }
0088
0089     return 0;
0090 }
0091
0092 static int ghash_flush(struct ghash_desc_ctx *dctx)
0093 {
0094     u8 *buf = dctx->buffer;
0095
0096     if (dctx->bytes) {
0097         u8 *pos = buf + (GHASH_BLOCK_SIZE - dctx->bytes);
0098
0099         memset(pos, 0, dctx->bytes);
0100         cpacf_kimd(CPACF_KIMD_GHASH, dctx, buf, GHASH_BLOCK_SIZE);
0101         dctx->bytes = 0;
0102     }
0103
0104     return 0;
0105 }
0106
0107 static int ghash_final(struct shash_desc *desc, u8 *dst)
0108 {
0109     struct ghash_desc_ctx *dctx = shash_desc_ctx(desc);
0110     int ret;
0111
0112     ret = ghash_flush(dctx);
0113     if (!ret)
0114         memcpy(dst, dctx->icv, GHASH_BLOCK_SIZE);
0115     return ret;
0116 }
0117
0118 static struct shash_alg ghash_alg = {
0119     .digestsize = GHASH_DIGEST_SIZE,
0120     .init       = ghash_init,
0121     .update     = ghash_update,
0122     .final      = ghash_final,
0123     .setkey     = ghash_setkey,
0124     .descsize   = sizeof(struct ghash_desc_ctx),
0125     .base       = {
0126         .cra_name       = "ghash",
0127         .cra_driver_name    = "ghash-s390",
0128         .cra_priority       = 300,
0129         .cra_blocksize      = GHASH_BLOCK_SIZE,
0130         .cra_ctxsize        = sizeof(struct ghash_ctx),
0131         .cra_module     = THIS_MODULE,
0132     },
0133 };
0134
0135 static int __init ghash_mod_init(void)
0136 {
0137     if (!cpacf_query_func(CPACF_KIMD, CPACF_KIMD_GHASH))
0138         return -ENODEV;
0139
0140     return crypto_register_shash(&ghash_alg);
0141 }
0142
0143 static void __exit ghash_mod_exit(void)
0144 {
0145     crypto_unregister_shash(&ghash_alg);
0146 }
0147
0148 module_cpu_feature_match(S390_CPU_FEATURE_MSA, ghash_mod_init);
0149 module_exit(ghash_mod_exit);
0150
0151 MODULE_ALIAS_CRYPTO("ghash");
0152
0153 MODULE_LICENSE("GPL");
0154 MODULE_DESCRIPTION("GHASH hash function, s390 implementation");