/* SPDX-License-Identifier: GPL-2.0+ */
/*
 * Copyright (c) 2013, Google Inc.
 *
 * (C) Copyright 2008 Semihalf
 *
 * (C) Copyright 2000-2006
 * Wolfgang Denk, DENX Software Engineering, wd@denx.de.
 */

#ifndef _RSA_H
#define _RSA_H

#include <errno.h>
#include <image.h>

/**
 * struct rsa_public_key - holder for a public key
 *
 * An RSA public key consists of a modulus (typically called N), the inverse
 * and R^2, where R is 2^(# key bits).
 */

struct rsa_public_key {
        uint len;               /* len of modulus[] in number of uint32_t */
        uint32_t n0inv;         /* -1 / modulus[0] mod 2^32 */
        uint32_t *modulus;      /* modulus as little endian array */
        uint32_t *rr;           /* R^2 as little endian array */
        uint64_t exponent;      /* public exponent */
};

struct image_sign_info;

#if IMAGE_ENABLE_SIGN
/**
 * sign() - calculate and return signature for given input data
 *
 * @info:       Specifies key and FIT information
 * @data:       Pointer to the input data
 * @data_len:   Data length
 * @sigp:       Set to an allocated buffer holding the signature
 * @sig_len:    Set to length of the calculated hash
 *
 * This computes input data signature according to selected algorithm.
 * Resulting signature value is placed in an allocated buffer, the
 * pointer is returned as *sigp. The length of the calculated
 * signature is returned via the sig_len pointer argument. The caller
 * should free *sigp.
 *
 * @return: 0, on success, -ve on error
 */
int rsa_sign(struct image_sign_info *info,
             const struct image_region region[],
             int region_count, uint8_t **sigp, uint *sig_len);

/**
 * add_verify_data() - Add verification information to FDT
 *
 * Add public key information to the FDT node, suitable for
 * verification at run-time. The information added depends on the
 * algorithm being used.
 *
 * @info:       Specifies key and FIT information
 * @keydest:    Destination FDT blob for public key data
 * @return: 0, on success, -ENOSPC if the keydest FDT blob ran out of space,
                other -ve value on error
*/
int rsa_add_verify_data(struct image_sign_info *info, void *keydest);
#else
static inline int rsa_sign(struct image_sign_info *info,
                const struct image_region region[], int region_count,
                uint8_t **sigp, uint *sig_len)
{
        return -ENXIO;
}

static inline int rsa_add_verify_data(struct image_sign_info *info,
                                      void *keydest)
{
        return -ENXIO;
}
#endif

#if IMAGE_ENABLE_VERIFY
/**
 * rsa_verify_hash() - Verify a signature against a hash
 *
 * Verify a RSA PKCS1.5 signature against an expected hash.
 *
 * @info:       Specifies key and FIT information
 * @hash:       Hash according to algorithm specified in @info
 * @sig:        Signature
 * @sig_len:    Number of bytes in signature
 * @return 0 if verified, -ve on error
 */
int rsa_verify_hash(struct image_sign_info *info,
                    const uint8_t *hash, uint8_t *sig, uint sig_len);

/**
 * rsa_verify() - Verify a signature against some data
 *
 * Verify a RSA PKCS1.5 signature against an expected hash.
 *
 * @info:       Specifies key and FIT information
 * @data:       Pointer to the input data
 * @data_len:   Data length
 * @sig:        Signature
 * @sig_len:    Number of bytes in signature
 * @return 0 if verified, -ve on error
 */
int rsa_verify(struct image_sign_info *info,
               const struct image_region region[], int region_count,
               uint8_t *sig, uint sig_len);

int rsa_verify_with_pkey(struct image_sign_info *info,
                         const void *hash, uint8_t *sig, uint sig_len);

int padding_pkcs_15_verify(struct image_sign_info *info,
                           uint8_t *msg, int msg_len,
                           const uint8_t *hash, int hash_len);

#ifdef CONFIG_FIT_ENABLE_RSASSA_PSS_SUPPORT
int padding_pss_verify(struct image_sign_info *info,
                       uint8_t *msg, int msg_len,
                       const uint8_t *hash, int hash_len);
#endif /* CONFIG_FIT_ENABLE_RSASSA_PSS_SUPPORT */
#else
static inline int rsa_verify_hash(struct image_sign_info *info,
                                  const uint8_t *hash,
                                  uint8_t *sig, uint sig_len)
{
        return -ENXIO;
}

static inline int rsa_verify(struct image_sign_info *info,
                const struct image_region region[], int region_count,
                uint8_t *sig, uint sig_len)
{
        return -ENXIO;
}

static inline int padding_pkcs_15_verify(struct image_sign_info *info,
                                         uint8_t *msg, int msg_len,
                                         const uint8_t *hash, int hash_len)
{
        return -ENXIO;
}

#ifdef CONFIG_FIT_ENABLE_RSASSA_PSS_SUPPORT
static inline int padding_pss_verify(struct image_sign_info *info,
                                     uint8_t *msg, int msg_len,
                                     const uint8_t *hash, int hash_len)
{
        return -ENXIO;
}
#endif /* CONFIG_FIT_ENABLE_RSASSA_PSS_SUPPORT */
#endif

#define RSA_DEFAULT_PADDING_NAME                "pkcs-1.5"

#define RSA2048_BYTES   (2048 / 8)
#define RSA4096_BYTES   (4096 / 8)

/* This is the minimum/maximum key size we support, in bits */
#define RSA_MIN_KEY_BITS        2048
#define RSA_MAX_KEY_BITS        4096

/* This is the maximum signature length that we support, in bits */
#define RSA_MAX_SIG_BITS        4096

#endif