path: root/drivers/crypto/ccree/cc_cipher.c

// SPDX-License-Identifier: GPL-2.0
/* Copyright (C) 2012-2019 ARM Limited (or its affiliates). */

#include <linux/kernel.h>
#include <linux/module.h>
#include <crypto/algapi.h>
#include <crypto/internal/skcipher.h>
#include <crypto/internal/des.h>
#include <crypto/xts.h>
#include <crypto/sm4.h>
#include <crypto/scatterwalk.h>

#include "cc_driver.h"
#include "cc_lli_defs.h"
#include "cc_buffer_mgr.h"
#include "cc_cipher.h"
#include "cc_request_mgr.h"

#define MAX_SKCIPHER_SEQ_LEN 6

#define template_skcipher	template_u.skcipher

struct cc_user_key_info {
	u8 *key;
	dma_addr_t key_dma_addr;
};

struct cc_hw_key_info {
	enum cc_hw_crypto_key key1_slot;
	enum cc_hw_crypto_key key2_slot;
};

struct cc_cpp_key_info {
	u8 slot;
	enum cc_cpp_alg alg;
};

enum cc_key_type {
	CC_UNPROTECTED_KEY,		/* User key */
	CC_HW_PROTECTED_KEY,		/* HW (FDE) key */
	CC_POLICY_PROTECTED_KEY,	/* CPP key */
	CC_INVALID_PROTECTED_KEY	/* Invalid key */
};

struct cc_cipher_ctx {
	struct cc_drvdata *drvdata;
	int keylen;
	int cipher_mode;
	int flow_mode;
	unsigned int flags;
	enum cc_key_type key_type;
	struct cc_user_key_info user;
	union {
		struct cc_hw_key_info hw;
		struct cc_cpp_key_info cpp;
	};
	struct crypto_shash *shash_tfm;
	struct crypto_skcipher *fallback_tfm;
	bool fallback_on;
};

static void cc_cipher_complete(struct device *dev, void *cc_req, int err);

static inline enum cc_key_type cc_key_type(struct crypto_tfm *tfm)
{
	struct cc_cipher_ctx *ctx_p = crypto_tfm_ctx(tfm);

	return ctx_p->key_type;
}

static int validate_keys_sizes(struct cc_cipher_ctx *ctx_p, u32 size)
{
	switch (ctx_p->flow_mode) {
	case S_DIN_to_AES:
		switch (size) {
		case CC_AES_128_BIT_KEY_SIZE:
		case CC_AES_192_BIT_KEY_SIZE:
			if (ctx_p->cipher_mode != DRV_CIPHER_XTS)
				return 0;
			break;
		case CC_AES_256_BIT_KEY_SIZE:
			return 0;
		case (CC_AES_192_BIT_KEY_SIZE * 2):
		case (CC_AES_256_BIT_KEY_SIZE * 2):
			if (ctx_p->cipher_mode == DRV_CIPHER_XTS ||
			    ctx_p->cipher_mode == DRV_CIPHER_ESSIV)
				return 0;
			break;
		default:
			break;
		}
		break;
	case S_DIN_to_DES:
		if (size == DES3_EDE_KEY_SIZE || size == DES_KEY_SIZE)
			return 0;
		break;
	case S_DIN_to_SM4:
		if (size == SM4_KEY_SIZE)
			return 0;
		break;
	default:
		break;
	}
	return -EINVAL;
}

static int validate_data_size(struct cc_cipher_ctx *ctx_p,
			      unsigned int size)
{
	switch (ctx_p->flow_mode) {
	case S_DIN_to_AES:
		switch (ctx_p->cipher_mode) {
		case DRV_CIPHER_XTS:
		case DRV_CIPHER_CBC_CTS:
			if (size >= AES_BLOCK_SIZE)
				return 0;
			break;
		case DRV_CIPHER_OFB:
		case DRV_CIPHER_CTR:
				return 0;
		case DRV_CIPHER_ECB:
		case DRV_CIPHER_CBC:
		case DRV_CIPHER_ESSIV:
			if (IS_ALIGNED(size, AES_BLOCK_SIZE))
				return 0;
			break;
		default:
			break;
		}
		break;
	case S_DIN_to_DES:
		if (IS_ALIGNED(size, DES_BLOCK_SIZE))
			return 0;
		break;
	case S_DIN_to_SM4:
		switch (ctx_p->cipher_mode) {
		case DRV_CIPHER_CTR:
			return 0;
		case DRV_CIPHER_ECB:
		case DRV_CIPHER_CBC:
			if (IS_ALIGNED(size, SM4_BLOCK_SIZE))
				return 0;
			break;
		default:
			break;
		}
		break;
	default:
		break;
	}
	return -EINVAL;
}

static int cc_cipher_init(struct crypto_tfm *tfm)
{
	struct cc_cipher_ctx *ctx_p = crypto_tfm_ctx(tfm);
	struct cc_crypto_alg *cc_alg =
			container_of(tfm->__crt_alg, struct cc_crypto_alg,
				     skcipher_alg.base);
	struct device *dev = drvdata_to_dev(cc_alg->drvdata);
	unsigned int max_key_buf_size = cc_alg->skcipher_alg.max_keysize;
	unsigned int fallback_req_size = 0;

	dev_dbg(dev, "Initializing context @%p for %s\n", ctx_p,
		crypto_tfm_alg_name(tfm));

	ctx_p->cipher_mode = cc_alg->cipher_mode;
	ctx_p->flow_mode = cc_alg->flow_mode;
	ctx_p->drvdata = cc_alg->drvdata;

	if (ctx_p->cipher_mode == DRV_CIPHER_ESSIV) {
		const char *name = crypto_tfm_alg_name(tfm);

		/* Alloc hash tfm for essiv */
		ctx_p->shash_tfm = crypto_alloc_shash("sha256", 0, 0);
		if (IS_ERR(ctx_p->shash_tfm)) {
			dev_err(dev, "Error allocating hash tfm for ESSIV.\n");
			return PTR_ERR(ctx_p->shash_tfm);
		}
		max_key_buf_size <<= 1;

		/* Alloc fallabck tfm or essiv when key size != 256 bit */
		ctx_p->fallback_tfm =
			crypto_alloc_skcipher(name, 0, CRYPTO_ALG_NEED_FALLBACK | CRYPTO_ALG_ASYNC);

		if (IS_ERR(ctx_p->fallback_tfm)) {
			/* Note we're still allowing registration with no fallback since it's
			 * better to have most modes supported than none at all.
			 */
			dev_warn(dev, "Error allocating fallback algo %s. Some modes may be available.\n",
			       name);
			ctx_p->fallback_tfm = NULL;
		} else {
			fallback_req_size = crypto_skcipher_reqsize(ctx_p->fallback_tfm);
		}
	}

	crypto_skcipher_set_reqsize(__crypto_skcipher_cast(tfm),
				    sizeof(struct cipher_req_ctx) + fallback_req_size);

	/* Allocate key buffer, cache line aligned */
	ctx_p->user.key = kzalloc(max_key_buf_size, GFP_KERNEL);
	if (!ctx_p->user.key)
		goto free_fallback;

	dev_dbg(dev, "Allocated key buffer in context. key=@%p\n",
		ctx_p->user.key);

	/* Map key buffer */
	ctx_p->user.key_dma_addr = dma_map_single(dev, ctx_p->user.key,
						  max_key_buf_size,
						  DMA_TO_DEVICE);
	if (dma_mapping_error(dev, ctx_p->user.key_dma_addr)) {
		dev_err(dev, "Mapping Key %u B at va=%pK for DMA failed\n",
			max_key_buf_size, ctx_p->user.key);
		goto free_key;
	}
	dev_dbg(dev, "Mapped key %u B at va=%pK to dma=%pad\n",
		max_key_buf_size, ctx_p->user.key, &ctx_p->user.key_dma_addr);

	return 0;

free_key:
	kfree(ctx_p->user.key);
free_fallback:
	crypto_free_skcipher(ctx_p->fallback_tfm);
	crypto_free_shash(ctx_p->shash_tfm);

	return -ENOMEM;
}

static void cc_cipher_exit(struct crypto_tfm *tfm)
{
	struct crypto_alg *alg = tfm->__crt_alg;
	struct cc_crypto_alg *cc_alg =
			container_of(alg, struct cc_crypto_alg,
				     skcipher_alg.base);
	unsigned int max_key_buf_size = cc_alg->skcipher_alg.max_keysize;
	struct cc_cipher_ctx *ctx_p = crypto_tfm_ctx(tfm);
	struct device *dev = drvdata_to_dev(ctx_p->drvdata);

	dev_dbg(dev, "Clearing context @%p for %s\n",
		crypto_tfm_ctx(tfm), crypto_tfm_alg_name(tfm));

	if (ctx_p->cipher_mode == DRV_CIPHER_ESSIV) {
		/* Free hash tfm for essiv */
		crypto_free_shash(ctx_p->shash_tfm);
		ctx_p->shash_tfm = NULL;
		crypto_free_skcipher(ctx_p->fallback_tfm);
		ctx_p->fallback_tfm = NULL;
	}

	/* Unmap key buffer */
	dma_unmap_single(dev, ctx_p->user.key_dma_addr, max_key_buf_size,
			 DMA_TO_DEVICE);
	dev_dbg(dev, "Unmapped key buffer key_dma_addr=%pad\n",
		&ctx_p->user.key_dma_addr);

	/* Free key buffer in context */
	kfree_sensitive(ctx_p->user.key);
	dev_dbg(dev, "Free key buffer in context. key=@%p\n", ctx_p->user.key);
}

struct tdes_keys {
	u8	key1[DES_KEY_SIZE];
	u8	key2[DES_KEY_SIZE];
	u8	key3[DES_KEY_SIZE];
};

static enum cc_hw_crypto_key cc_slot_to_hw_key(u8 slot_num)
{
	switch (slot_num) {
	case 0:
		return KFDE0_KEY;
	case 1:
		return KFDE1_KEY;
	case 2:
		return KFDE2_KEY;
	case 3:
		return KFDE3_KEY;
	}
	return END_OF_KEYS;
}

static u8 cc_slot_to_cpp_key(u8 slot_num)
{
	return (slot_num - CC_FIRST_CPP_KEY_SLOT);
}

static inline enum cc_key_type cc_slot_to_key_type(u8 slot_num)
{
	if (slot_num >= CC_FIRST_HW_KEY_SLOT && slot_num <= CC_LAST_HW_KEY_SLOT)
		return CC_HW_PROTECTED_KEY;
	else if (slot_num >=  CC_FIRST_CPP_KEY_SLOT &&
		 slot_num <=  CC_LAST_CPP_KEY_SLOT)
		return CC_POLICY_PROTECTED_KEY;
	else
		return CC_INVALID_PROTECTED_KEY;
}

static int cc_cipher_sethkey(struct crypto_skcipher *sktfm, const u8 *key,
			     unsigned int keylen)
{
	struct crypto_tfm *tfm = crypto_skcipher_tfm(sktfm);
	struct cc_cipher_ctx *ctx_p = crypto_tfm_ctx(tfm);
	struct device *dev = drvdata_to_dev(ctx_p->drvdata);
	struct cc_hkey_info hki;

	dev_dbg(dev, "Setting HW key in context @%p for %s. keylen=%u\n",
		ctx_p, crypto_tfm_alg_name(tfm), keylen);
	dump_byte_array("key", key, keylen);

	/* STAT_PHASE_0: Init and sanity checks */

	/* This check the size of the protected key token */
	if (keylen != sizeof(hki)) {
		dev_err(dev, "Unsu