unplugged-kernel/drivers/mmc/core/mmc_crypto.c

// SPDX-License-Identifier: GPL-2.0
/*
 * Copyright (C) 2019 MediaTek Inc.
 */

#include <crypto/algapi.h>
#include <linux/mmc/host.h>
#include "mmc_crypto.h"
#include "queue.h"

static bool mmc_cap_idx_valid(struct mmc_host *host, u8 cap_idx)
{
	return cap_idx < host->crypto_capabilities.num_crypto_cap;
}

static u8 get_data_unit_size_mask(unsigned int data_unit_size)
{
	if (data_unit_size < 512 || data_unit_size > 65536 ||
	    !is_power_of_2(data_unit_size))
		return 0;

	return data_unit_size / 512;
}

static size_t get_keysize_bytes(enum swcqhci_crypto_key_size size)
{
	switch (size) {
	case SWCQHCI_CRYPTO_KEY_SIZE_128: return 16;
	case SWCQHCI_CRYPTO_KEY_SIZE_192: return 24;
	case SWCQHCI_CRYPTO_KEY_SIZE_256: return 32;
	default: return 0;
	}
}

static u8 mmc_crypto_cap_find(void *mmc_p,
				  enum blk_crypto_mode_num crypto_mode,
				  unsigned int data_unit_size)
{
	struct mmc_host *host = mmc_p;
	enum swcqhci_crypto_alg mmc_alg;
	u8 data_unit_mask, cap_idx;
	enum swcqhci_crypto_key_size mmc_key_size;
	union swcqhci_crypto_cap_entry *ccap_array = host->crypto_cap_array;

	if (!mmc_is_crypto_supported(host))
		return -EINVAL;

	switch (crypto_mode) {
	case BLK_ENCRYPTION_MODE_AES_256_XTS:
		/* "4" means XTS */
		mmc_alg = SWCQHCI_CRYPTO_ALG_AES_XTS;
		/* "2" means 256 bits */
		mmc_key_size = SWCQHCI_CRYPTO_KEY_SIZE_256;
		break;
	default:
		return -EINVAL;
	}

	data_unit_mask = get_data_unit_size_mask(data_unit_size);
	/* There is only one capability */
	for (cap_idx = 0; cap_idx < host->crypto_capabilities.num_crypto_cap;
	     cap_idx++) {
		if (ccap_array[cap_idx].algorithm_id == mmc_alg &&
		    (ccap_array[cap_idx].sdus_mask & data_unit_mask) &&
		    ccap_array[cap_idx].key_size == mmc_key_size)
			return cap_idx;
	}
	return -EINVAL;
}

/**
 * mmc_crypto_cfg_entry_write_key - Write a key into a crypto_cfg_entry
 *
 *	Writes the key with the appropriate format - for AES_XTS,
 *	the first half of the key is copied as is, the second half is
 *	copied with an offset halfway into the cfg->crypto_key array.
 *	For the other supported crypto algs, the key is just copied.
 *
 * @cfg: The crypto config to write to
 * @key: The key to write
 * @cap: The crypto capability (which specifies the crypto alg and key size)
 *
 * Returns 0 on success, or -EINVAL
 */
static int mmc_crypto_cfg_entry_write_key(union swcqhci_crypto_cfg_entry *cfg,
					     const u8 *key,
					     union swcqhci_crypto_cap_entry cap)
{
	size_t key_size_bytes = get_keysize_bytes(cap.key_size);

	if (key_size_bytes == 0)
		return -EINVAL;

	switch (cap.algorithm_id) {
	case SWCQHCI_CRYPTO_ALG_INVALID: /* non-cqe */
	case SWCQHCI_CRYPTO_ALG_AES_XTS:
		key_size_bytes *= 2;
		if (key_size_bytes > MMC_CRYPTO_KEY_MAX_SIZE)
			return -EINVAL;

		memcpy(cfg->crypto_key, key, key_size_bytes/2);
		memcpy(cfg->crypto_key + MMC_CRYPTO_KEY_MAX_SIZE/2,
		       key + key_size_bytes/2, key_size_bytes/2);
		return 0;
	case SWCQHCI_CRYPTO_ALG_BITLOCKER_AES_CBC: // fallthrough
	case SWCQHCI_CRYPTO_ALG_AES_ECB: // fallthrough
	case SWCQHCI_CRYPTO_ALG_ESSIV_AES_CBC:
		memcpy(cfg->crypto_key, key, key_size_bytes);
		return 0;
	}

	return -EINVAL;
}

static int mmc_crypto_keyslot_program(struct keyslot_manager *ksm,
			const struct blk_crypto_key *key,
			unsigned int slot)

{
	struct mmc_host *host = keyslot_manager_private(ksm);
	int err = 0;
	u8 data_unit_mask;
	union swcqhci_crypto_cfg_entry cfg;
	union swcqhci_crypto_cfg_entry *cfg_arr;
	u8 cap_idx;

	if (!host || !key)
		return -EINVAL;

	cfg_arr = host->crypto_cfgs;

	cap_idx = mmc_crypto_cap_find(host, key->crypto_mode,
					       key->data_unit_size);

	if (!mmc_is_crypto_enabled(host) ||
	    !mmc_keyslot_valid(host, slot) ||
	    !mmc_cap_idx_valid(host, cap_idx))
		return -EINVAL;

	data_unit_mask = get_data_unit_size_mask(key->data_unit_size);

	if (!(data_unit_mask & host->crypto_cap_array[cap_idx].sdus_mask))
		return -EINVAL;

	memset(&cfg, 0, sizeof(cfg));

	cfg.data_unit_size = data_unit_mask;
#ifdef CONFIG_MMC_CRYPTO_LEGACY
	/* used fsrypt v2 in OTA fscrypt v1 environment */
	if (key->hie_duint_size != 4096)
		cfg.data_unit_size = 1;
#endif

	cfg.crypto_cap_idx = cap_idx;
	cfg.config_enable |= MMC_CRYPTO_CONFIGURATION_ENABLE;

	err = mmc_crypto_cfg_entry_write_key(&cfg, key->raw,
				host->crypto_cap_array[cap_idx]);
	if (err)
		return err;

	memcpy(&cfg_arr[slot], &cfg, sizeof(cfg));
	memzero_explicit(&cfg, sizeof(cfg));

	return 0;
}

static int mmc_crypto_keyslot_evict(struct keyslot_manager *ksm,
			const struct blk_crypto_key *key,
			unsigned int slot)
{
	struct mmc_host *host = keyslot_manager_private(ksm);
	union swcqhci_crypto_cfg_entry *cfg_arr = host->crypto_cfgs;

	if (!mmc_is_crypto_enabled(host) ||
	    !mmc_keyslot_valid(host, slot))
		return -EINVAL;

	memset(&cfg_arr[slot], 0, sizeof(cfg_arr[slot]));

	return 0;
}

static const struct keyslot_mgmt_ll_ops swcq_ksm_ops = {
	.keyslot_program	= mmc_crypto_keyslot_program,
	.keyslot_evict		= mmc_crypto_keyslot_evict,
};

/**
 * mmc_init_crypto_spec - Read crypto capabilities, init crypto fields in host
 * @host: Per adapter instance
 *
 * Returns 0 on success. Returns -ENODEV if such capabilities don't exist, and
 * -ENOMEM upon OOM.
 */
static int mmc_init_crypto_spec(struct mmc_host *host,
		const struct keyslot_mgmt_ll_ops *ksm_ops)
{
	int err;
	u32 count;
	unsigned int crypto_modes_supported[BLK_ENCRYPTION_MODE_MAX] = {0};

	if (host->ksm)
		return 0;

	if (!(host->caps2 & MMC_CAP2_CRYPTO)) {
		err = -ENODEV;
		goto out;
	}

	/*
	 * Crypto Capabilities should never be 0, because the
	 * config_array_ptr != 0. So we use a 0 value to indicate that
	 * crypto init failed, and can't be enabled.
	 */
	if (host->crypto_vops->host_init_crypto)
		host->crypto_vops->host_init_crypto(host);

	count = ((u32)(host->crypto_capabilities.num_crypto_cap) & 0xFF);
	host->crypto_cap_array =
		devm_kcalloc(&host->class_dev,
			     count,
			     sizeof(host->crypto_cap_array[0]),
			     GFP_KERNEL);
	if (!host->crypto_cap_array) {
		err = -ENOMEM;
		goto out;
	}

	/*
	 * Store all the capabilities now so that we don't need to repeatedly
	 * access the device each time we want to know its capabilities
	 */
	if (host->crypto_vops->get_crypto_capabilities)
		err = host->crypto_vops->get_crypto_capabilities(host);
	if (err)
		goto out_free_cfg_mem;

	host->crypto_cfgs =
		devm_kcalloc(&host->class_dev,
			     NUM_KEYSLOTS(host),
			     sizeof(host->crypto_cfgs[0]),
			     GFP_KERNEL);
	if (!host->crypto_cfgs) {
		err = -ENOMEM;
		goto out_free_cfg_mem;
	}
	/* Peng: temp */
	crypto_modes_supported[1] = 0x1200;

	host->ksm = keyslot_manager_create(host->parent,
		NUM_KEYSLOTS(host), ksm_ops,
		BLK_CRYPTO_FEATURE_STANDARD_KEYS,
		crypto_modes_supported, host);

	if (!host->ksm) {
		err = -ENOMEM;
		goto out_free_crypto_cfgs;
	}

	return 0;
out_free_crypto_cfgs:
	devm_kfree(&host->class_dev, host->crypto_cfgs);
out_free_cfg_mem:
	devm_kfree(&host->class_dev, host->crypto_cap_array);
out:
	// TODO: print error?
	/* Indicate that init failed by setting crypto_capabilities to 0 */
	host->crypto_capabilities.reg_val = 0;

	return err;
}

static int mmc_prepare_mqr_crypto_spec(struct mmc_host *host,
		struct mmc_queue_req *mqr)
{
	struct bio_crypt_ctx *bc;
	struct request *request = mmc_queue_req_to_req(mqr);

	if (!request->bio ||
	    !bio_crypt_should_process(request)) {
		return 0;
	}
	bc = request->bio->bi_crypt_context;
	if (!mmc_keyslot_valid(host, bc->bc_keyslot))
		return -EINVAL;

	mqr->brq.mrq.crypto_key_slot = bc->bc_keyslot;
	/*
	 * OTA with ext4 (dun is 512 bytes) used LBA,
	 * with F2FS (dun is 512 bytes), the dun[0] had
	 * multiplied by 8.
	 */
	if (bc->hie_ext4 == true)
		mqr->brq.mrq.data_unit_num =
			(blk_rq_pos(request) & 0xFFFFFFFF);
	else
		mqr->brq.mrq.data_unit_num = bc->bc_dun[0];
	mqr->brq.mrq.crypto_key = bc->bc_key;
	return 0;
}

int mmc_init_crypto(struct mmc_host *host)
{
	if (!(host->caps2 & MMC_CAP2_NO_SD))
		return 0;

	host->caps2 |= MMC_CAP2_CRYPTO;

	return mmc_init_crypto_spec(host, &swcq_ksm_ops);
}

int mmc_swcq_prepare_mqr_crypto(struct mmc_host *host,
		struct mmc_request *mrq)
{
	int ret, ddir, slot, tag;
	struct request *req;
	struct mmc_queue_req *mqr;

	req = mrq->req;
	mqr = req_to_mmc_queue_req(req);

	ret = mmc_prepare_mqr_crypto_spec(host, mqr);
	if (ret || !mmc_request_crypto_enabled(&(mqr->brq.mrq)))
		return ret;

	/* non-CQE */
	if (!(host->caps2 & (MMC_CAP2_CQE | MMC_CAP2_CQE_DCMD))) {
		ddir = rq_data_dir(req);
		slot = req->bio->bi_crypt_context->bc_keyslot;
		tag = mqr->brq.mrq.tag;
		if (host->crypto_vops && host->crypto_vops->prepare_mqr_crypto)
			return host->crypto_vops->prepare_mqr_crypto(host,
			mqr->brq.mrq.data_unit_num, ddir, tag, slot);
	}

	return 0;
}

int mmc_complete_mqr_crypto(struct mmc_host *host)
{
	if (host->crypto_vops && host->crypto_vops->complete_mqr_crypto)
		return host->crypto_vops->complete_mqr_crypto(host);

	return 0;
}