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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 <linux/cpufeature.h>
- #include <asm/cpacf.h>
- #define GHASH_BLOCK_SIZE 16
- #define GHASH_DIGEST_SIZE 16
- struct ghash_ctx {
- u8 key[GHASH_BLOCK_SIZE];
- };
- struct ghash_desc_ctx {
- u8 icv[GHASH_BLOCK_SIZE];
- u8 key[GHASH_BLOCK_SIZE];
- u8 buffer[GHASH_BLOCK_SIZE];
- u32 bytes;
- };
- static int ghash_init(struct shash_desc *desc)
- {
- struct ghash_desc_ctx *dctx = shash_desc_ctx(desc);
- struct ghash_ctx *ctx = crypto_shash_ctx(desc->tfm);
- memset(dctx, 0, sizeof(*dctx));
- memcpy(dctx->key, ctx->key, GHASH_BLOCK_SIZE);
- 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);
- 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);
- unsigned int n;
- u8 *buf = dctx->buffer;
- 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) {
- cpacf_kimd(CPACF_KIMD_GHASH, dctx, buf,
- GHASH_BLOCK_SIZE);
- }
- }
- n = srclen & ~(GHASH_BLOCK_SIZE - 1);
- if (n) {
- cpacf_kimd(CPACF_KIMD_GHASH, dctx, src, n);
- src += n;
- srclen -= n;
- }
- if (srclen) {
- dctx->bytes = GHASH_BLOCK_SIZE - srclen;
- memcpy(buf, src, srclen);
- }
- return 0;
- }
- static int ghash_flush(struct ghash_desc_ctx *dctx)
- {
- u8 *buf = dctx->buffer;
- if (dctx->bytes) {
- u8 *pos = buf + (GHASH_BLOCK_SIZE - dctx->bytes);
- memset(pos, 0, dctx->bytes);
- cpacf_kimd(CPACF_KIMD_GHASH, dctx, buf, GHASH_BLOCK_SIZE);
- dctx->bytes = 0;
- }
- return 0;
- }
- static int ghash_final(struct shash_desc *desc, u8 *dst)
- {
- struct ghash_desc_ctx *dctx = shash_desc_ctx(desc);
- int ret;
- ret = ghash_flush(dctx);
- if (!ret)
- memcpy(dst, dctx->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 = 300,
- .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 (!cpacf_query_func(CPACF_KIMD, CPACF_KIMD_GHASH))
- return -EOPNOTSUPP;
- return crypto_register_shash(&ghash_alg);
- }
- static void __exit ghash_mod_exit(void)
- {
- crypto_unregister_shash(&ghash_alg);
- }
- module_cpu_feature_match(MSA, ghash_mod_init);
- module_exit(ghash_mod_exit);
- MODULE_ALIAS_CRYPTO("ghash");
- MODULE_LICENSE("GPL");
- MODULE_DESCRIPTION("GHASH Message Digest Algorithm, s390 implementation");
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