167 lines
3.3 KiB
C
167 lines
3.3 KiB
C
/*
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* Cryptographic API.
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*
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* s390 implementation of the GHASH algorithm for GCM (Galois/Counter Mode).
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*
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* Copyright IBM Corp. 2011
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* Author(s): Gerald Schaefer <gerald.schaefer@de.ibm.com>
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*/
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#include <crypto/internal/hash.h>
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#include <linux/module.h>
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#include "crypt_s390.h"
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#define GHASH_BLOCK_SIZE 16
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#define GHASH_DIGEST_SIZE 16
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struct ghash_ctx {
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u8 icv[16];
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u8 key[16];
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};
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struct ghash_desc_ctx {
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u8 buffer[GHASH_BLOCK_SIZE];
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u32 bytes;
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};
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static int ghash_init(struct shash_desc *desc)
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{
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struct ghash_desc_ctx *dctx = shash_desc_ctx(desc);
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memset(dctx, 0, sizeof(*dctx));
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return 0;
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}
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static int ghash_setkey(struct crypto_shash *tfm,
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const u8 *key, unsigned int keylen)
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{
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struct ghash_ctx *ctx = crypto_shash_ctx(tfm);
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if (keylen != GHASH_BLOCK_SIZE) {
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crypto_shash_set_flags(tfm, CRYPTO_TFM_RES_BAD_KEY_LEN);
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return -EINVAL;
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}
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memcpy(ctx->key, key, GHASH_BLOCK_SIZE);
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memset(ctx->icv, 0, GHASH_BLOCK_SIZE);
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return 0;
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}
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static int ghash_update(struct shash_desc *desc,
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const u8 *src, unsigned int srclen)
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{
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struct ghash_desc_ctx *dctx = shash_desc_ctx(desc);
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struct ghash_ctx *ctx = crypto_shash_ctx(desc->tfm);
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unsigned int n;
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u8 *buf = dctx->buffer;
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int ret;
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if (dctx->bytes) {
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u8 *pos = buf + (GHASH_BLOCK_SIZE - dctx->bytes);
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n = min(srclen, dctx->bytes);
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dctx->bytes -= n;
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srclen -= n;
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memcpy(pos, src, n);
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src += n;
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if (!dctx->bytes) {
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ret = crypt_s390_kimd(KIMD_GHASH, ctx, buf,
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GHASH_BLOCK_SIZE);
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if (ret != GHASH_BLOCK_SIZE)
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return -EIO;
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}
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}
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n = srclen & ~(GHASH_BLOCK_SIZE - 1);
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if (n) {
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ret = crypt_s390_kimd(KIMD_GHASH, ctx, src, n);
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if (ret != n)
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return -EIO;
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src += n;
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srclen -= n;
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}
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if (srclen) {
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dctx->bytes = GHASH_BLOCK_SIZE - srclen;
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memcpy(buf, src, srclen);
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}
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return 0;
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}
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static int ghash_flush(struct ghash_ctx *ctx, struct ghash_desc_ctx *dctx)
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{
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u8 *buf = dctx->buffer;
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int ret;
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if (dctx->bytes) {
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u8 *pos = buf + (GHASH_BLOCK_SIZE - dctx->bytes);
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memset(pos, 0, dctx->bytes);
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ret = crypt_s390_kimd(KIMD_GHASH, ctx, buf, GHASH_BLOCK_SIZE);
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if (ret != GHASH_BLOCK_SIZE)
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return -EIO;
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}
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dctx->bytes = 0;
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return 0;
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}
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static int ghash_final(struct shash_desc *desc, u8 *dst)
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{
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struct ghash_desc_ctx *dctx = shash_desc_ctx(desc);
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struct ghash_ctx *ctx = crypto_shash_ctx(desc->tfm);
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int ret;
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ret = ghash_flush(ctx, dctx);
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if (!ret)
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memcpy(dst, ctx->icv, GHASH_BLOCK_SIZE);
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return ret;
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}
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static struct shash_alg ghash_alg = {
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.digestsize = GHASH_DIGEST_SIZE,
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.init = ghash_init,
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.update = ghash_update,
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.final = ghash_final,
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.setkey = ghash_setkey,
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.descsize = sizeof(struct ghash_desc_ctx),
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.base = {
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.cra_name = "ghash",
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.cra_driver_name = "ghash-s390",
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.cra_priority = CRYPT_S390_PRIORITY,
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.cra_flags = CRYPTO_ALG_TYPE_SHASH,
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.cra_blocksize = GHASH_BLOCK_SIZE,
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.cra_ctxsize = sizeof(struct ghash_ctx),
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.cra_module = THIS_MODULE,
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},
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};
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static int __init ghash_mod_init(void)
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{
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if (!crypt_s390_func_available(KIMD_GHASH,
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CRYPT_S390_MSA | CRYPT_S390_MSA4))
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return -EOPNOTSUPP;
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return crypto_register_shash(&ghash_alg);
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}
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static void __exit ghash_mod_exit(void)
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{
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crypto_unregister_shash(&ghash_alg);
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}
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module_init(ghash_mod_init);
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module_exit(ghash_mod_exit);
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MODULE_ALIAS("ghash");
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MODULE_LICENSE("GPL");
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MODULE_DESCRIPTION("GHASH Message Digest Algorithm, s390 implementation");
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