/* SPDX-License-Identifier: GPL-2.0+ */
/*
 *  Copyright IBM Corp. 2001, 2006
 *  Author(s): Robert Burroughs
 *             Eric Rossman (edrossma@us.ibm.com)
 *
 *  Hotplug & misc device support: Jochen Roehrig (roehrig@de.ibm.com)
 *  Major cleanup & driver split: Martin Schwidefsky <schwidefsky@de.ibm.com>
 */

#ifndef _ZCRYPT_CCA_KEY_H_
#define _ZCRYPT_CCA_KEY_H_

struct T6_keyBlock_hdr {
        unsigned short blen;
        unsigned short ulen;
        unsigned short flags;
};

/**
 * mapping for the cca private ME key token.
 * Three parts of interest here: the header, the private section and
 * the public section.
 *
 * mapping for the cca key token header
 */
struct cca_token_hdr {
        unsigned char  token_identifier;
        unsigned char  version;
        unsigned short token_length;
        unsigned char  reserved[4];
} __packed;

#define CCA_TKN_HDR_ID_EXT 0x1E

#define CCA_PVT_USAGE_ALL 0x80

/**
 * mapping for the cca public section
 * In a private key, the modulus doesn't appear in the public
 * section. So, an arbitrary public exponent of 0x010001 will be
 * used, for a section length of 0x0F always.
 */
struct cca_public_sec {
        unsigned char  section_identifier;
        unsigned char  version;
        unsigned short section_length;
        unsigned char  reserved[2];
        unsigned short exponent_len;
        unsigned short modulus_bit_len;
        unsigned short modulus_byte_len;    /* In a private key, this is 0 */
} __packed;

/**
 * mapping for the cca private CRT key 'token'
 * The first three parts (the only parts considered in this release)
 * are: the header, the private section and the public section.
 * The header and public section are the same as for the
 * struct cca_private_ext_ME
 *
 * Following the structure are the quantities p, q, dp, dq, u, pad,
 * and modulus, in that order, where pad_len is the modulo 8
 * complement of the residue modulo 8 of the sum of
 * (p_len + q_len + dp_len + dq_len + u_len).
 */
struct cca_pvt_ext_CRT_sec {
        unsigned char  section_identifier;
        unsigned char  version;
        unsigned short section_length;
        unsigned char  private_key_hash[20];
        unsigned char  reserved1[4];
        unsigned char  key_format;
        unsigned char  reserved2;
        unsigned char  key_name_hash[20];
        unsigned char  key_use_flags[4];
        unsigned short p_len;
        unsigned short q_len;
        unsigned short dp_len;
        unsigned short dq_len;
        unsigned short u_len;
        unsigned short mod_len;
        unsigned char  reserved3[4];
        unsigned short pad_len;
        unsigned char  reserved4[52];
        unsigned char  confounder[8];
} __packed;

#define CCA_PVT_EXT_CRT_SEC_ID_PVT 0x08
#define CCA_PVT_EXT_CRT_SEC_FMT_CL 0x40

/**
 * Set up private key fields of a type6 MEX message. The _pad variant
 * strips leading zeroes from the b_key.
 * Note that all numerics in the key token are big-endian,
 * while the entries in the key block header are little-endian.
 *
 * @mex: pointer to user input data
 * @p: pointer to memory area for the key
 *
 * Returns the size of the key area or negative errno value.
 */
static inline int zcrypt_type6_mex_key_en(struct ica_rsa_modexpo *mex, void *p)
{
        static struct cca_token_hdr static_pub_hdr = {
                .token_identifier       =  0x1E,
        };
        static struct cca_public_sec static_pub_sec = {
                .section_identifier     =  0x04,
        };
        struct {
                struct T6_keyBlock_hdr t6_hdr;
                struct cca_token_hdr pubHdr;
                struct cca_public_sec pubSec;
                char exponent[0];
        } __packed *key = p;
        unsigned char *temp;
        int i;

        /*
         * The inputdatalength was a selection criteria in the dispatching
         * function zcrypt_rsa_modexpo(). However, do a plausibility check
         * here to make sure the following copy_from_user() can't be utilized
         * to compromise the system.
         */
        if (WARN_ON_ONCE(mex->inputdatalength > 512))
                return -EINVAL;

        memset(key, 0, sizeof(*key));

        key->pubHdr = static_pub_hdr;
        key->pubSec = static_pub_sec;

        /* key parameter block */
        temp = key->exponent;
        if (copy_from_user(temp, mex->b_key, mex->inputdatalength))
                return -EFAULT;
        /* Strip leading zeroes from b_key. */
        for (i = 0; i < mex->inputdatalength; i++)
                if (temp[i])
                        break;
        if (i >= mex->inputdatalength)
                return -EINVAL;
        memmove(temp, temp + i, mex->inputdatalength - i);
        temp += mex->inputdatalength - i;
        /* modulus */
        if (copy_from_user(temp, mex->n_modulus, mex->inputdatalength))
                return -EFAULT;

        key->pubSec.modulus_bit_len = 8 * mex->inputdatalength;
        key->pubSec.modulus_byte_len = mex->inputdatalength;
        key->pubSec.exponent_len = mex->inputdatalength - i;
        key->pubSec.section_length = sizeof(key->pubSec) +
                                        2*mex->inputdatalength - i;
        key->pubHdr.token_length =
                key->pubSec.section_length + sizeof(key->pubHdr);
        key->t6_hdr.ulen = key->pubHdr.token_length + 4;
        key->t6_hdr.blen = key->pubHdr.token_length + 6;
        return sizeof(*key) + 2*mex->inputdatalength - i;
}

/**
 * Set up private key fields of a type6 CRT message.
 * Note that all numerics in the key token are big-endian,
 * while the entries in the key block header are little-endian.
 *
 * @mex: pointer to user input data
 * @p: pointer to memory area for the key
 *
 * Returns the size of the key area or -EFAULT
 */
static inline int zcrypt_type6_crt_key(struct ica_rsa_modexpo_crt *crt, void *p)
{
        static struct cca_public_sec static_cca_pub_sec = {
                .section_identifier = 4,
                .section_length = 0x000f,
                .exponent_len = 0x0003,
        };
        static char pk_exponent[3] = { 0x01, 0x00, 0x01 };
        struct {
                struct T6_keyBlock_hdr t6_hdr;
                struct cca_token_hdr token;
                struct cca_pvt_ext_CRT_sec pvt;
                char key_parts[0];
        } __packed *key = p;
        struct cca_public_sec *pub;
        int short_len, long_len, pad_len, key_len, size;

        /*
         * The inputdatalength was a selection criteria in the dispatching
         * function zcrypt_rsa_crt(). However, do a plausibility check
         * here to make sure the following copy_from_user() can't be utilized
         * to compromise the system.
         */
        if (WARN_ON_ONCE(crt->inputdatalength > 512))
                return -EINVAL;

        memset(key, 0, sizeof(*key));

        short_len = (crt->inputdatalength + 1) / 2;
        long_len = short_len + 8;
        pad_len = -(3*long_len + 2*short_len) & 7;
        key_len = 3*long_len + 2*short_len + pad_len + crt->inputdatalength;
        size = sizeof(*key) + key_len + sizeof(*pub) + 3;

        /* parameter block.key block */
        key->t6_hdr.blen = size;
        key->t6_hdr.ulen = size - 2;

        /* key token header */
        key->token.token_identifier = CCA_TKN_HDR_ID_EXT;
        key->token.token_length = size - 6;

        /* private section */
        key->pvt.section_identifier = CCA_PVT_EXT_CRT_SEC_ID_PVT;
        key->pvt.section_length = sizeof(key->pvt) + key_len;
        key->pvt.key_format = CCA_PVT_EXT_CRT_SEC_FMT_CL;
        key->pvt.key_use_flags[0] = CCA_PVT_USAGE_ALL;
        key->pvt.p_len = key->pvt.dp_len = key->pvt.u_len = long_len;
        key->pvt.q_len = key->pvt.dq_len = short_len;
        key->pvt.mod_len = crt->inputdatalength;
        key->pvt.pad_len = pad_len;

        /* key parts */
        if (copy_from_user(key->key_parts, crt->np_prime, long_len) ||
            copy_from_user(key->key_parts + long_len,
                                        crt->nq_prime, short_len) ||
            copy_from_user(key->key_parts + long_len + short_len,
                                        crt->bp_key, long_len) ||
            copy_from_user(key->key_parts + 2*long_len + short_len,
                                        crt->bq_key, short_len) ||
            copy_from_user(key->key_parts + 2*long_len + 2*short_len,
                                        crt->u_mult_inv, long_len))
                return -EFAULT;
        memset(key->key_parts + 3*long_len + 2*short_len + pad_len,
               0xff, crt->inputdatalength);
        pub = (struct cca_public_sec *)(key->key_parts + key_len);
        *pub = static_cca_pub_sec;
        pub->modulus_bit_len = 8 * crt->inputdatalength;
        /*
         * In a private key, the modulus doesn't appear in the public
         * section. So, an arbitrary public exponent of 0x010001 will be
         * used.
         */
        memcpy((char *) (pub + 1), pk_exponent, 3);
        return size;
}

#endif /* _ZCRYPT_CCA_KEY_H_ */