/*
 * spu-sign-verify.c - When SPU fireware update, image signature verify.
 *
 * Author: JJungs-lee <jhs2.lee@samsung.com>
 *
 */
#define pr_fmt(fmt) "[sec_input] spu_verify: " fmt

#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/string.h>
#include <linux/export.h>
#include <linux/module.h>
#include <linux/printk.h>
#include <linux/types.h>
#include <linux/slab.h>
#include <linux/ctype.h>
#include <linux/fcntl.h>
#include <linux/syscalls.h>
#include <linux/file.h>
#include <linux/uaccess.h>
#include <crypto/public_key.h>
#include <crypto/hash.h>

//#include <linux/spu-verify.h>
#include "spu-sign-verify.h"

#define FW_DIGEST_MISMATCH 999

const char *spu_tag_name[] = { TSP_TAG, WACOM_TAG };

const u8 PublicKey[] = {
	0x30, 0x82, 0x02, 0x0a, 0x02, 0x82, 0x02, 0x01,
	0x00, 0xc6, 0xe9, 0x59, 0xe8, 0xb0, 0xda, 0x2e,
	0x8d, 0x4a, 0xa9, 0x09, 0x64, 0x51, 0xe5, 0x4e,
	0xb3, 0x7c, 0x18, 0x59, 0xc5, 0x6a, 0x1d, 0xce,
	0x11, 0x98, 0xb3, 0x44, 0x5b, 0x96, 0x88, 0xf2,
	0x27, 0x3b, 0x33, 0x55, 0x94, 0xa9, 0xdd, 0x51,
	0x76, 0x6f, 0x9f, 0xc3, 0x3c, 0x2e, 0x86, 0x7d,
	0x24, 0xea, 0x0c, 0x5f, 0xcd, 0x6c, 0x83, 0xa1,
	0xca, 0x34, 0x58, 0x03, 0x7f, 0x5a, 0x84, 0x91,
	0xc6, 0xc7, 0x1f, 0xd2, 0x8b, 0x00, 0xef, 0xe4,
	0xd4, 0xd7, 0x19, 0x15, 0x4b, 0x29, 0x15, 0x06,
	0x6f, 0x61, 0x8f, 0xe5, 0x27, 0xc8, 0x9d, 0x80,
	0xba, 0x87, 0x11, 0xdd, 0xd8, 0x69, 0xee, 0x73,
	0xb4, 0x2b, 0xb2, 0xee, 0xed, 0xcc, 0x17, 0x51,
	0x80, 0xd3, 0xf6, 0xb8, 0x35, 0x9b, 0x1d, 0xff,
	0xdf, 0xc1, 0xbb, 0x2b, 0x8f, 0xe8, 0x72, 0xb0,
	0x24, 0xf0, 0x84, 0xab, 0xf3, 0x0d, 0x04, 0xb4,
	0xc2, 0xc7, 0xbb, 0x59, 0x44, 0x1c, 0xc9, 0xef,
	0x3d, 0x53, 0x97, 0x42, 0x11, 0xed, 0x1e, 0xbf,
	0xed, 0x5a, 0x68, 0xa6, 0x2c, 0xce, 0xc0, 0xcf,
	0x82, 0x16, 0xb4, 0xc3, 0x8b, 0xdb, 0xb0, 0x7d,
	0xe2, 0x7b, 0x10, 0x59, 0x3d, 0x6a, 0x76, 0x73,
	0x95, 0x84, 0xef, 0x34, 0xd7, 0xfc, 0xc1, 0x28,
	0xf1, 0xfc, 0xd3, 0x89, 0x06, 0xca, 0xa0, 0x60,
	0x6b, 0xd4, 0xba, 0x3b, 0xa6, 0xcf, 0x3d, 0xba,
	0x9d, 0xeb, 0xec, 0x4d, 0x99, 0x4a, 0x17, 0x21,
	0x62, 0x61, 0x3b, 0x28, 0x1a, 0xdf, 0x99, 0xe8,
	0x23, 0x63, 0x26, 0xea, 0xb3, 0x58, 0x7a, 0x0e,
	0xbe, 0x37, 0xe8, 0x8c, 0x81, 0xf9, 0x84, 0x68,
	0x0c, 0x5f, 0x6c, 0xa6, 0xa8, 0xc7, 0x14, 0x09,
	0x90, 0x71, 0x5d, 0x7a, 0x1c, 0x40, 0x4e, 0x11,
	0x3c, 0xa2, 0x04, 0x0c, 0xd2, 0xd1, 0x02, 0x54,
	0x5b, 0x51, 0xcf, 0xbf, 0xc8, 0x1b, 0x34, 0xf7,
	0x8b, 0x12, 0x1f, 0xe2, 0x54, 0x2d, 0xac, 0xad,
	0x2f, 0x75, 0x63, 0xef, 0xd6, 0x67, 0x1a, 0xdd,
	0x5c, 0xf5, 0x62, 0x97, 0x59, 0x76, 0x84, 0x30,
	0x9a, 0x59, 0xd7, 0x7e, 0x14, 0x02, 0xa8, 0xdf,
	0x29, 0x0d, 0x11, 0x04, 0x70, 0x7f, 0x97, 0xcc,
	0x6d, 0x27, 0x03, 0xfc, 0x61, 0x03, 0x1d, 0x2b,
	0x7c, 0x65, 0x87, 0xfa, 0x0c, 0x0c, 0x75, 0xc6,
	0x4c, 0x4d, 0xe0, 0x14, 0x3a, 0x31, 0x14, 0xa1,
	0xde, 0x2e, 0xb0, 0xbf, 0xce, 0x9e, 0x32, 0x8d,
	0x89, 0x43, 0x0c, 0x02, 0xda, 0xd0, 0xe8, 0x5b,
	0xd7, 0x3a, 0x5f, 0x2c, 0x9d, 0x63, 0x69, 0x26,
	0x43, 0xe4, 0x64, 0x0f, 0xe4, 0x75, 0x45, 0x2c,
	0x51, 0x9e, 0x52, 0x97, 0xa8, 0x99, 0x1b, 0x58,
	0xc1, 0x1b, 0x3a, 0xfd, 0x13, 0xec, 0x92, 0xbc,
	0x4d, 0xdc, 0x9e, 0x31, 0x5d, 0xb2, 0x17, 0x5e,
	0x7e, 0x25, 0x98, 0xac, 0x9f, 0x38, 0xcb, 0x2a,
	0xca, 0x6b, 0xbf, 0xba, 0x32, 0xf0, 0xab, 0xac,
	0x69, 0x49, 0x06, 0xb2, 0x87, 0xcc, 0x60, 0xb3,
	0x75, 0xaf, 0xd4, 0xd1, 0xec, 0xa1, 0x75, 0x31,
	0x4c, 0x82, 0x31, 0x6d, 0xcd, 0xc8, 0xf6, 0xce,
	0xbd, 0x5d, 0x52, 0xd8, 0xac, 0xe2, 0x9b, 0x62,
	0x66, 0x70, 0x06, 0x7e, 0x88, 0xde, 0x57, 0x25,
	0xb2, 0x25, 0x13, 0x85, 0x50, 0x1b, 0xfa, 0x95,
	0x61, 0xd9, 0xb8, 0xcf, 0x79, 0x2b, 0x0a, 0xe2,
	0x9f, 0xf1, 0x5e, 0xff, 0xfc, 0x19, 0x17, 0x83,
	0x66, 0x93, 0xc5, 0x03, 0xd2, 0x0e, 0x27, 0x84,
	0xdb, 0xaa, 0xdc, 0xcc, 0xda, 0x57, 0x4f, 0x6e,
	0xf5, 0x45, 0xc0, 0xb2, 0xa8, 0x01, 0x31, 0xc4,
	0xab, 0x74, 0xaf, 0xb0, 0xa1, 0x27, 0x42, 0xe7,
	0x2c, 0x3e, 0x36, 0xd8, 0xcc, 0xf8, 0x05, 0xfc,
	0x66, 0x77, 0x1c, 0x15, 0xbd, 0x92, 0x12, 0x33,
	0xd9, 0xc0, 0x0a, 0xf3, 0xca, 0x5c, 0x6f, 0xde,
	0x69, 0x02, 0x03, 0x01, 0x00, 0x01
};

static int calc_digest_from_image(const u8 *data, const long size, u8 *digest)
{
	int ret = 0;
	struct crypto_shash *tfm = NULL;
	struct shash_desc *desc = NULL;
	const char *alg_name = "sha256";

	if (!data || !digest || size < 0) {
		pr_err("--> %s) invalid parameter\n", __func__);
		return -EINVAL;
	}

	tfm = crypto_alloc_shash(alg_name, CRYPTO_ALG_TYPE_SHASH, 0);
	if (IS_ERR(tfm)) {
		pr_err("--> %s) can't alloc tfm\n", __func__);
		return PTR_ERR(tfm);
	}

	desc = kzalloc(sizeof(struct shash_desc) + crypto_shash_descsize(tfm), GFP_KERNEL);
	if (!desc) {
		pr_err("--> %s) can't alloc desc\n", __func__);
		ret = PTR_ERR(desc);
		goto fail_desc;
	}

	desc->tfm = tfm;

	ret = crypto_shash_init(desc);
	if (ret < 0) {
		pr_err("--> %s) crypto_shash_init() failed\n", __func__);
		goto out;
	}

	ret = crypto_shash_update(desc, data, size);
	if (ret < 0) {
		pr_err("--> %s) crypto_shash_update() failed\n", __func__);
		goto out;
	}

	ret = crypto_shash_final(desc, digest);
	if (ret < 0)
		pr_err("--> %s) crypto_shash_final() failed\n", __func__);

out:
	if (desc)
		kfree(desc);
fail_desc:
	crypto_free_shash(tfm);

	return ret;
}

long spu_firmware_signature_verify(const char *fw_name, const u8 *fw_data, const long fw_size)
{
	int i = 0;
	int ret = 0;
	long fw_offset = fw_size;
	long TAG_LEN = 0;
	struct public_key *rsa_pub_key = NULL;
	struct public_key_signature *sig = NULL;

	u8 *signature = NULL;
	u8 read_digest[DIGEST_LEN] = { 0x00, };
	u8 calc_digest[DIGEST_LEN] = { 0x00, };

	if (!fw_name || !fw_data || fw_size < 0) {
		pr_info("invalid parameter...\n");
		return -EINVAL;
	}

	pr_info("%s requested for signature verify\n", fw_name);

	for (i = 0; i < ARRAY_SIZE(spu_tag_name); ++i) {
		TAG_LEN = strlen(spu_tag_name[i]);
		if (strncmp(fw_name, spu_tag_name[i], TAG_LEN) == 0) {
			ret = 1;
			break;
		}
	}

	if (!ret) {
		pr_info("This firmware don't support...\n");
		return -1;
	}

	signature = kzalloc(SIGN_LEN, GFP_KERNEL);
	if (!signature) {
		pr_err("signature kmalloc ERROR\n");
		return -ENOMEM;
	}

	fw_offset -= SIGN_LEN;
	memcpy(signature, fw_data + fw_offset, SIGN_LEN);

	fw_offset -= DIGEST_LEN;
	memcpy(read_digest, fw_data + fw_offset, DIGEST_LEN);

	fw_offset -= TAG_LEN;
	if (TAG_LEN <= 0 || strncmp(fw_name, fw_data + fw_offset, TAG_LEN) != 0) {
		pr_info("Firmware mismatch...\n");
		ret = -FW_DIGEST_MISMATCH;
		goto fail_mismatch;
	}

	fw_offset += TAG_LEN;
	ret = calc_digest_from_image(fw_data, fw_offset, calc_digest);
	if (ret < 0) {
		pr_err("calc_digest_from_image ERROR\n");
		goto fail_mismatch;
	}

	if (memcmp(read_digest, calc_digest, DIGEST_LEN) != 0) {
		pr_err("digset matching FAILED...\n");
		ret = -FW_DIGEST_MISMATCH;
		goto fail_mismatch;
	}

	rsa_pub_key = kzalloc(sizeof(struct public_key), GFP_KERNEL);
	if (!rsa_pub_key) {
		pr_err("rsa_pub_key kmalloc ERROR\n");
		ret = -ENOMEM;
		goto fail_mismatch;
	}

	sig = kzalloc(sizeof(struct public_key_signature), GFP_KERNEL);
	if (!sig) {
		pr_err("sig kmalloc ERROR\n");
		ret = -ENOMEM;
		goto fail_sig;
	}

	rsa_pub_key->key = (void *)PublicKey;
	rsa_pub_key->keylen = (u32)(sizeof(PublicKey));
	rsa_pub_key->id_type = "X509";
	rsa_pub_key->pkey_algo = "rsa";

	sig->s = signature;
	sig->s_size = (u32)SIGN_LEN;
	sig->digest = calc_digest;
	sig->digest_size = (u8)DIGEST_LEN;
	sig->pkey_algo = "rsa";
	sig->hash_algo = "sha256";
	sig->encoding = "pkcs1";

	ret = public_key_verify_signature(rsa_pub_key, sig);
	if (ret) {
		pr_info("verifying ERROR(%d)\n", ret);
	} else {
		pr_info("verified successfully!!!\n");
		ret = fw_offset - TAG_LEN;
	}

	if (sig)
		kfree(sig);
fail_sig:
	if (rsa_pub_key)
		kfree(rsa_pub_key);
fail_mismatch:
	if (signature)
		kfree(signature);

	return ret;
}
EXPORT_SYMBOL(spu_firmware_signature_verify);