path: root/arch/s390/crypto/aes_s390.c

// SPDX-License-Identifier: GPL-2.0+
/*
 * Cryptographic API.
 *
 * s390 implementation of the AES Cipher Algorithm.
 *
 * s390 Version:
 *   Copyright IBM Corp. 2005, 2017
 *   Author(s): Jan Glauber (jang@de.ibm.com)
 *		Sebastian Siewior (sebastian@breakpoint.cc> SW-Fallback
 *		Patrick Steuer <patrick.steuer@de.ibm.com>
 *		Harald Freudenberger <freude@de.ibm.com>
 *
 * Derived from "crypto/aes_generic.c"
 */

#define KMSG_COMPONENT "aes_s390"
#define pr_fmt(fmt) KMSG_COMPONENT ": " fmt

#include <crypto/aes.h>
#include <crypto/algapi.h>
#include <crypto/ghash.h>
#include <crypto/internal/aead.h>
#include <crypto/internal/cipher.h>
#include <crypto/internal/skcipher.h>
#include <crypto/scatterwalk.h>
#include <linux/err.h>
#include <linux/module.h>
#include <linux/cpufeature.h>
#include <linux/init.h>
#include <linux/mutex.h>
#include <linux/fips.h>
#include <linux/string.h>
#include <crypto/xts.h>
#include <asm/cpacf.h>

static u8 *ctrblk;
static DEFINE_MUTEX(ctrblk_lock);

static cpacf_mask_t km_functions, kmc_functions, kmctr_functions,
		    kma_functions;

struct s390_aes_ctx {
	u8 key[AES_MAX_KEY_SIZE];
	int key_len;
	unsigned long fc;
	union {
		struct crypto_skcipher *skcipher;
		struct crypto_cipher *cip;
	} fallback;
};

struct s390_xts_ctx {
	u8 key[32];
	u8 pcc_key[32];
	int key_len;
	unsigned long fc;
	struct crypto_skcipher *fallback;
};

struct gcm_sg_walk {
	struct scatter_walk walk;
	unsigned int walk_bytes;
	u8 *walk_ptr;
	unsigned int walk_bytes_remain;
	u8 buf[AES_BLOCK_SIZE];
	unsigned int buf_bytes;
	u8 *ptr;
	unsigned int nbytes;
};

static int setkey_fallback_cip(struct crypto_tfm *tfm, const u8 *in_key,
		unsigned int key_len)
{
	struct s390_aes_ctx *sctx = crypto_tfm_ctx(tfm);

	sctx->fallback.cip->base.crt_flags &= ~CRYPTO_TFM_REQ_MASK;
	sctx->fallback.cip->base.crt_flags |= (tfm->crt_flags &
			CRYPTO_TFM_REQ_MASK);

	return crypto_cipher_setkey(sctx->fallback.cip, in_key, key_len);
}

static int aes_set_key(struct crypto_tfm *tfm, const u8 *in_key,
		       unsigned int key_len)
{
	struct s390_aes_ctx *sctx = crypto_tfm_ctx(tfm);
	unsigned long fc;

	/* Pick the correct function code based on the key length */
	fc = (key_len == 16) ? CPACF_KM_AES_128 :
	     (key_len == 24) ? CPACF_KM_AES_192 :
	     (key_len == 32) ? CPACF_KM_AES_256 : 0;

	/* Check if the function code is available */
	sctx->fc = (fc && cpacf_test_func(&km_functions, fc)) ? fc : 0;
	if (!sctx->fc)
		return setkey_fallback_cip(tfm, in_key, key_len);

	sctx->key_len = key_len;
	memcpy(sctx->key, in_key, key_len);
	return 0;
}

static void crypto_aes_encrypt(struct crypto_tfm *tfm, u8 *out, const u8 *in)
{
	struct s390_aes_ctx *sctx = crypto_tfm_ctx(tfm);

	if (unlikely(!sctx->fc)) {
		crypto_cipher_encrypt_one(sctx->fallback.cip, out, in);
		return;
	}
	cpacf_km(sctx->fc, &sctx->key, out, in, AES_BLOCK_SIZE);
}

static void crypto_aes_decrypt(struct crypto_tfm *tfm, u8 *out, const u8 *in)
{
	struct s390_aes_ctx *sctx = crypto_tfm_ctx(tfm);

	if (unlikely(!sctx->fc)) {
		crypto_cipher_decrypt_one(sctx->fallback.cip, out, in);
		return;
	}
	cpacf_km(sctx->fc | CPACF_DECRYPT,
		 &sctx->key, out, in, AES_BLOCK_SIZE);
}

static int fallback_init_cip(struct crypto_tfm *tfm)
{
	const char *name = tfm->__crt_alg->cra_name;
	struct s390_aes_ctx *sctx = crypto_tfm_ctx(tfm);

	sctx->fallback.cip = crypto_alloc_cipher(name, 0,
						 CRYPTO_ALG_NEED_FALLBACK);

	if (IS_ERR(sctx->fallback.cip)) {
		pr_err("Allocating AES fallback algorithm %s failed\n",
		       name);
		return PTR_ERR(sctx->fallback.cip);
	}

	return 0;
}

static void fallback_exit_cip(struct crypto_tfm *tfm)
{
	struct s390_aes_ctx *sctx = crypto_tfm_ctx(tfm);

	crypto_free_cipher(sctx->fallback.cip);
	sctx->fallback.cip = NULL;
}

static struct crypto_alg aes_alg = {
	.cra_name		=	"aes",
	.cra_driver_name	=	"aes-s390",
	.cra_priority		=	300,
	.cra_flags		=	CRYPTO_ALG_TYPE_CIPHER |
					CRYPTO_ALG_NEED_FALLBACK,
	.cra_blocksize		=	AES_BLOCK_SIZE,
	.cra_ctxsize		=	sizeof(struct s390_aes_ctx),
	.cra_module		=	THIS_MODULE,
	.cra_init               =       fallback_init_cip,
	.cra_exit               =       fallback_exit_cip,
	.cra_u			=	{
		.cipher = {
			.cia_min_keysize	=	AES_MIN_KEY_SIZE,
			.