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/*

 *  Public Key layer for parsing key files and structures

 *

 *  Copyright (C) 2006-2015, ARM Limited, All Rights Reserved

 *  SPDX-License-Identifier: GPL-2.0

 *

 *  This program is free software; you can redistribute it and/or modify

 *  it under the terms of the GNU General Public License as published by

 *  the Free Software Foundation; either version 2 of the License, or

 *  (at your option) any later version.

 *

 *  This program is distributed in the hope that it will be useful,

 *  but WITHOUT ANY WARRANTY; without even the implied warranty of

 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

 *  GNU General Public License for more details.

 *

 *  You should have received a copy of the GNU General Public License along

 *  with this program; if not, write to the Free Software Foundation, Inc.,

 *  51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.

 *

 *  This file is part of mbed TLS (https://tls.mbed.org)

 */

#if !defined(MBEDTLS_CONFIG_FILE)

#include "mbedtls/config.h"

#else

#include MBEDTLS_CONFIG_FILE

#endif

#if defined(MBEDTLS_PK_PARSE_C)

#include "mbedtls/pk.h"

#include "mbedtls/asn1.h"

#include "mbedtls/oid.h"

#include "mbedtls/platform_util.h"

#include 

#if defined(MBEDTLS_RSA_C)

#include "mbedtls/rsa.h"

#endif

#if defined(MBEDTLS_ECP_C)

#include "mbedtls/ecp.h"

#endif

#if defined(MBEDTLS_ECDSA_C)

#include "mbedtls/ecdsa.h"

#endif

#if defined(MBEDTLS_PEM_PARSE_C)

#include "mbedtls/pem.h"

#endif

#if defined(MBEDTLS_PKCS5_C)

#include "mbedtls/pkcs5.h"

#endif

#if defined(MBEDTLS_PKCS12_C)

#include "mbedtls/pkcs12.h"

#endif

#if defined(MBEDTLS_PLATFORM_C)

#include "mbedtls/platform.h"

#else

#include 

#define mbedtls_calloc    calloc

#define mbedtls_free       free

#endif

/* Parameter validation macros based on platform_util.h */

#define PK_VALIDATE_RET( cond )    \

    MBEDTLS_INTERNAL_VALIDATE_RET( cond, MBEDTLS_ERR_PK_BAD_INPUT_DATA )

#define PK_VALIDATE( cond )        \

    MBEDTLS_INTERNAL_VALIDATE( cond )

#if defined(MBEDTLS_FS_IO)

/*

 * Load all data from a file into a given buffer.

 *

 * The file is expected to contain either PEM or DER encoded data.

 * A terminating null byte is always appended. It is included in the announced

 * length only if the data looks like it is PEM encoded.

 */

int mbedtls_pk_load_file( const char *path, unsigned char **buf, size_t *n )

{

    FILE *f;

    long size;

    PK_VALIDATE_RET( path != NULL );

    PK_VALIDATE_RET( buf != NULL );

    PK_VALIDATE_RET( n != NULL );

    if( ( f = fopen( path, "rb" ) ) == NULL )

        return( MBEDTLS_ERR_PK_FILE_IO_ERROR );

    fseek( f, 0, SEEK_END );

    if( ( size = ftell( f ) ) == -1 )

    {

        fclose( f );

        return( MBEDTLS_ERR_PK_FILE_IO_ERROR );

    }

    fseek( f, 0, SEEK_SET );

    *n = (size_t) size;

    if( *n + 1 == 0 ||

        ( *buf = mbedtls_calloc( 1, *n + 1 ) ) == NULL )

    {

        fclose( f );

        return( MBEDTLS_ERR_PK_ALLOC_FAILED );

    }

    if( fread( *buf, 1, *n, f ) != *n )

    {

        fclose( f );

        mbedtls_platform_zeroize( *buf, *n );

        mbedtls_free( *buf );

        return( MBEDTLS_ERR_PK_FILE_IO_ERROR );

    }

    fclose( f );

    (*buf)[*n] = '\0';

    if( strstr( (const char *) *buf, "-----BEGIN " ) != NULL )

        ++*n;

    return( 0 );

}

/*

 * Load and parse a private key

 */

int mbedtls_pk_parse_keyfile( mbedtls_pk_context *ctx,

                      const char *path, const char *pwd )

{

    int ret;

    size_t n;

    unsigned char *buf;

    PK_VALIDATE_RET( ctx != NULL );

    PK_VALIDATE_RET( path != NULL );

    if( ( ret = mbedtls_pk_load_file( path, &buf, &n ) ) != 0 )

        return( ret );

    if( pwd == NULL )

        ret = mbedtls_pk_parse_key( ctx, buf, n, NULL, 0 );

    else

        ret = mbedtls_pk_parse_key( ctx, buf, n,

                (const unsigned char *) pwd, strlen( pwd ) );

    mbedtls_platform_zeroize( buf, n );

    mbedtls_free( buf );

    return( ret );

}

/*

 * Load and parse a public key

 */

int mbedtls_pk_parse_public_keyfile( mbedtls_pk_context *ctx, const char *path )

{

    int ret;

    size_t n;

    unsigned char *buf;

    PK_VALIDATE_RET( ctx != NULL );

    PK_VALIDATE_RET( path != NULL );

    if( ( ret = mbedtls_pk_load_file( path, &buf, &n ) ) != 0 )

        return( ret );

    ret = mbedtls_pk_parse_public_key( ctx, buf, n );

    mbedtls_platform_zeroize( buf, n );

    mbedtls_free( buf );

    return( ret );

}

#endif /* MBEDTLS_FS_IO */

#if defined(MBEDTLS_ECP_C)

/* Minimally parse an ECParameters buffer to and mbedtls_asn1_buf

 *

 * ECParameters ::= CHOICE {

 *   namedCurve         OBJECT IDENTIFIER

 *   specifiedCurve     SpecifiedECDomain -- = SEQUENCE { ... }

 *   -- implicitCurve   NULL

 * }

 */

static int pk_get_ecparams( unsigned char **p, const unsigned char *end,

                            mbedtls_asn1_buf *params )

{

    int ret;

    if ( end - *p < 1 )

        return( MBEDTLS_ERR_PK_KEY_INVALID_FORMAT +

                MBEDTLS_ERR_ASN1_OUT_OF_DATA );

    /* Tag may be either OID or SEQUENCE */

    params->tag = **p;

    if( params->tag != MBEDTLS_ASN1_OID

#if defined(MBEDTLS_PK_PARSE_EC_EXTENDED)

            && params->tag != ( MBEDTLS_ASN1_CONSTRUCTED | MBEDTLS_ASN1_SEQUENCE )

#endif

            )

    {

        return( MBEDTLS_ERR_PK_KEY_INVALID_FORMAT +

                MBEDTLS_ERR_ASN1_UNEXPECTED_TAG );

    }

    if( ( ret = mbedtls_asn1_get_tag( p, end, ¶ms->len, params->tag ) ) != 0 )

    {

        return( MBEDTLS_ERR_PK_KEY_INVALID_FORMAT + ret );

    }

    params->p = *p;

    *p += params->len;

    if( *p != end )

        return( MBEDTLS_ERR_PK_KEY_INVALID_FORMAT +

                MBEDTLS_ERR_ASN1_LENGTH_MISMATCH );

    return( 0 );

}

#if defined(MBEDTLS_PK_PARSE_EC_EXTENDED)

/*

 * Parse a SpecifiedECDomain (SEC 1 C.2) and (mostly) fill the group with it.

 * WARNING: the resulting group should only be used with

 * pk_group_id_from_specified(), since its base point may not be set correctly

 * if it was encoded compressed.

 *

 *  SpecifiedECDomain ::= SEQUENCE {

 *      version SpecifiedECDomainVersion(ecdpVer1 | ecdpVer2 | ecdpVer3, ...),

 *      fieldID FieldID {{FieldTypes}},

 *      curve Curve,

 *      base ECPoint,

 *      order INTEGER,

 *      cofactor INTEGER OPTIONAL,

 *      hash HashAlgorithm OPTIONAL,

 *      ...

 *  }

 *

 * We only support prime-field as field type, and ignore hash and cofactor.

 */

static int pk_group_from_specified( const mbedtls_asn1_buf *params, mbedtls_ecp_group *grp )

{

    int ret;

    unsigned char *p = params->p;

    const unsigned char * const end = params->p + params->len;

    const unsigned char *end_field, *end_curve;

    size_t len;

    int ver;

    /* SpecifiedECDomainVersion ::= INTEGER { 1, 2, 3 } */

    if( ( ret = mbedtls_asn1_get_int( &p, end, &ver ) ) != 0 )

        return( MBEDTLS_ERR_PK_KEY_INVALID_FORMAT + ret );

    if( ver < 1 || ver > 3 )

        return( MBEDTLS_ERR_PK_KEY_INVALID_FORMAT );

    /*

     * FieldID { FIELD-ID:IOSet } ::= SEQUENCE { -- Finite field

     *       fieldType FIELD-ID.&id({IOSet}),

     *       parameters FIELD-ID.&Type({IOSet}{@fieldType})

     * }

     */

    if( ( ret = mbedtls_asn1_get_tag( &p, end, &len,

            MBEDTLS_ASN1_CONSTRUCTED | MBEDTLS_ASN1_SEQUENCE ) ) != 0 )

        return( ret );

    end_field = p + len;

    /*

     * FIELD-ID ::= TYPE-IDENTIFIER

     * FieldTypes FIELD-ID ::= {

     *       { Prime-p IDENTIFIED BY prime-field } |

     *       { Characteristic-two IDENTIFIED BY characteristic-two-field }

     * }

     * prime-field OBJECT IDENTIFIER ::= { id-fieldType 1 }

     */

    if( ( ret = mbedtls_asn1_get_tag( &p, end_field, &len, MBEDTLS_ASN1_OID ) ) != 0 )

        return( ret );

    if( len != MBEDTLS_OID_SIZE( MBEDTLS_OID_ANSI_X9_62_PRIME_FIELD ) ||

        memcmp( p, MBEDTLS_OID_ANSI_X9_62_PRIME_FIELD, len ) != 0 )

    {

        return( MBEDTLS_ERR_PK_FEATURE_UNAVAILABLE );

    }

    p += len;

    /* Prime-p ::= INTEGER -- Field of size p. */

    if( ( ret = mbedtls_asn1_get_mpi( &p, end_field, &grp->P ) ) != 0 )

        return( MBEDTLS_ERR_PK_KEY_INVALID_FORMAT + ret );

    grp->pbits = mbedtls_mpi_bitlen( &grp->P );

    if( p != end_field )

        return( MBEDTLS_ERR_PK_KEY_INVALID_FORMAT +

                MBEDTLS_ERR_ASN1_LENGTH_MISMATCH );

    /*

     * Curve ::= SEQUENCE {

     *       a FieldElement,

     *       b FieldElement,

     *       seed BIT STRING OPTIONAL

     *       -- Shall be present if used in SpecifiedECDomain

     *       -- with version equal to ecdpVer2 or ecdpVer3

     * }

     */

    if( ( ret = mbedtls_asn1_get_tag( &p, end, &len,

            MBEDTLS_ASN1_CONSTRUCTED | MBEDTLS_ASN1_SEQUENCE ) ) != 0 )

        return( ret );

    end_curve = p + len;

    /*

     * FieldElement ::= OCTET STRING

     * containing an integer in the case of a prime field

     */

    if( ( ret = mbedtls_asn1_get_tag( &p, end_curve, &len, MBEDTLS_ASN1_OCTET_STRING ) ) != 0 ||

        ( ret = mbedtls_mpi_read_binary( &grp->A, p, len ) ) != 0 )

    {

        return( MBEDTLS_ERR_PK_KEY_INVALID_FORMAT + ret );

    }

    p += len;

    if( ( ret = mbedtls_asn1_get_tag( &p, end_curve, &len, MBEDTLS_ASN1_OCTET_STRING ) ) != 0 ||

        ( ret = mbedtls_mpi_read_binary( &grp->B, p, len ) ) != 0 )

    {

        return( MBEDTLS_ERR_PK_KEY_INVALID_FORMAT + ret );

    }

    p += len;

    /* Ignore seed BIT STRING OPTIONAL */

    if( ( ret = mbedtls_asn1_get_tag( &p, end_curve, &len, MBEDTLS_ASN1_BIT_STRING ) ) == 0 )

        p += len;

    if( p != end_curve )

        return( MBEDTLS_ERR_PK_KEY_INVALID_FORMAT +

                MBEDTLS_ERR_ASN1_LENGTH_MISMATCH );

    /*

     * ECPoint ::= OCTET STRING

     */

    if( ( ret = mbedtls_asn1_get_tag( &p, end, &len, MBEDTLS_ASN1_OCTET_STRING ) ) != 0 )

        return( MBEDTLS_ERR_PK_KEY_INVALID_FORMAT + ret );

    if( ( ret = mbedtls_ecp_point_read_binary( grp, &grp->G,

                                      ( const unsigned char *) p, len ) ) != 0 )

    {

        /*

         * If we can't read the point because it's compressed, cheat by

         * reading only the X coordinate and the parity bit of Y.

         */

        if( ret != MBEDTLS_ERR_ECP_FEATURE_UNAVAILABLE ||

            ( p[0] != 0x02 && p[0] != 0x03 ) ||

            len != mbedtls_mpi_size( &grp->P ) + 1 ||

            mbedtls_mpi_read_binary( &grp->G.X, p + 1, len - 1 ) != 0 ||

            mbedtls_mpi_lset( &grp->G.Y, p[0] - 2 ) != 0 ||

            mbedtls_mpi_lset( &grp->G.Z, 1 ) != 0 )

        {

            return( MBEDTLS_ERR_PK_KEY_INVALID_FORMAT );

        }

    }

    p += len;

    /*

     * order INTEGER

     */

    if( ( ret = mbedtls_asn1_get_mpi( &p, end, &grp->N ) ) != 0 )

        return( MBEDTLS_ERR_PK_KEY_INVALID_FORMAT + ret );

    grp->nbits = mbedtls_mpi_bitlen( &grp->N );

    /*

     * Allow optional elements by purposefully not enforcing p == end here.

     */

    return( 0 );

}

/*

 * Find the group id associated with an (almost filled) group as generated by

 * pk_group_from_specified(), or return an error if unknown.

 */

static int pk_group_id_from_group( const mbedtls_ecp_group *grp, mbedtls_ecp_group_id *grp_id )

{

    int ret = 0;

    mbedtls_ecp_group ref;

    const mbedtls_ecp_group_id *id;

    mbedtls_ecp_group_init( &ref );

    for( id = mbedtls_ecp_grp_id_list(); *id != MBEDTLS_ECP_DP_NONE; id++ )

    {

        /* Load the group associated to that id */

        mbedtls_ecp_group_free( &ref );

        MBEDTLS_MPI_CHK( mbedtls_ecp_group_load( &ref, *id ) );

        /* Compare to the group we were given, starting with easy tests */

        if( grp->pbits == ref.pbits && grp->nbits == ref.nbits &&

            mbedtls_mpi_cmp_mpi( &grp->P, &ref.P ) == 0 &&

            mbedtls_mpi_cmp_mpi( &grp->A, &ref.A ) == 0 &&

            mbedtls_mpi_cmp_mpi( &grp->B, &ref.B ) == 0 &&

            mbedtls_mpi_cmp_mpi( &grp->N, &ref.N ) == 0 &&

            mbedtls_mpi_cmp_mpi( &grp->G.X, &ref.G.X ) == 0 &&

            mbedtls_mpi_cmp_mpi( &grp->G.Z, &ref.G.Z ) == 0 &&

            /* For Y we may only know the parity bit, so compare only that */

            mbedtls_mpi_get_bit( &grp->G.Y, 0 ) == mbedtls_mpi_get_bit( &ref.G.Y, 0 ) )

        {

            break;

        }

    }

cleanup:

    mbedtls_ecp_group_free( &ref );

    *grp_id = *id;

    if( ret == 0 && *id == MBEDTLS_ECP_DP_NONE )

        ret = MBEDTLS_ERR_ECP_FEATURE_UNAVAILABLE;

    return( ret );

}

/*

 * Parse a SpecifiedECDomain (SEC 1 C.2) and find the associated group ID

 */

static int pk_group_id_from_specified( const mbedtls_asn1_buf *params,

                                       mbedtls_ecp_group_id *grp_id )

{

    int ret;

    mbedtls_ecp_group grp;

    mbedtls_ecp_group_init( &grp );

    if( ( ret = pk_group_from_specified( params, &grp ) ) != 0 )

        goto cleanup;

    ret = pk_group_id_from_group( &grp, grp_id );

cleanup:

    mbedtls_ecp_group_free( &grp );

    return( ret );

}

#endif /* MBEDTLS_PK_PARSE_EC_EXTENDED */

/*

 * Use EC parameters to initialise an EC group

 *

 * ECParameters ::= CHOICE {

 *   namedCurve         OBJECT IDENTIFIER

 *   specifiedCurve     SpecifiedECDomain -- = SEQUENCE { ... }

 *   -- implicitCurve   NULL

 */

static int pk_use_ecparams( const mbedtls_asn1_buf *params, mbedtls_ecp_group *grp )

{

    int ret;

    mbedtls_ecp_group_id grp_id;

    if( params->tag == MBEDTLS_ASN1_OID )

    {

        if( mbedtls_oid_get_ec_grp( params, &grp_id ) != 0 )

            return( MBEDTLS_ERR_PK_UNKNOWN_NAMED_CURVE );

    }

    else

    {

#if defined(MBEDTLS_PK_PARSE_EC_EXTENDED)

        if( ( ret = pk_group_id_from_specified( params, &grp_id ) ) != 0 )

            return( ret );

#else

        return( MBEDTLS_ERR_PK_KEY_INVALID_FORMAT );

#endif

    }

    /*

     * grp may already be initilialized; if so, make sure IDs match

     */

    if( grp->id != MBEDTLS_ECP_DP_NONE && grp->id != grp_id )

        return( MBEDTLS_ERR_PK_KEY_INVALID_FORMAT );

    if( ( ret = mbedtls_ecp_group_load( grp, grp_id ) ) != 0 )

        return( ret );

    return( 0 );

}

/*

 * EC public key is an EC point

 *

 * The caller is responsible for clearing the structure upon failure if

 * desired. Take care to pass along the possible ECP_FEATURE_UNAVAILABLE

 * return code of mbedtls_ecp_point_read_binary() and leave p in a usable state.

 */

static int pk_get_ecpubkey( unsigned char **p, const unsigned char *end,

                            mbedtls_ecp_keypair *key )

{

    int ret;

    if( ( ret = mbedtls_ecp_point_read_binary( &key->grp, &key->Q,

                    (const unsigned char *) *p, end - *p ) ) == 0 )

    {

        ret = mbedtls_ecp_check_pubkey( &key->grp, &key->Q );

    }

    /*

     * We know mbedtls_ecp_point_read_binary consumed all bytes or failed

     */

    *p = (unsigned char *) end;

    return( ret );

}

#endif /* MBEDTLS_ECP_C */

#if defined(MBEDTLS_RSA_C)

/*

 *  RSAPublicKey ::= SEQUENCE {

 *      modulus           INTEGER,  -- n

 *      publicExponent    INTEGER   -- e

 *  }

 */

static int pk_get_rsapubkey( unsigned char **p,

                             const unsigned char *end,

                             mbedtls_rsa_context *rsa )

{

    int ret;

    size_t len;

    if( ( ret = mbedtls_asn1_get_tag( p, end, &len,

            MBEDTLS_ASN1_CONSTRUCTED | MBEDTLS_ASN1_SEQUENCE ) ) != 0 )

        return( MBEDTLS_ERR_PK_INVALID_PUBKEY + ret );

    if( *p + len != end )

        return( MBEDTLS_ERR_PK_INVALID_PUBKEY +

                MBEDTLS_ERR_ASN1_LENGTH_MISMATCH );

    /* Import N */

    if( ( ret = mbedtls_asn1_get_tag( p, end, &len, MBEDTLS_ASN1_INTEGER ) ) != 0 )

        return( MBEDTLS_ERR_PK_INVALID_PUBKEY + ret );

    if( ( ret = mbedtls_rsa_import_raw( rsa, *p, len, NULL, 0, NULL, 0,

                                        NULL, 0, NULL, 0 ) ) != 0 )

        return( MBEDTLS_ERR_PK_INVALID_PUBKEY );

    *p += len;

    /* Import E */

    if( ( ret = mbedtls_asn1_get_tag( p, end, &len, MBEDTLS_ASN1_INTEGER ) ) != 0 )

        return( MBEDTLS_ERR_PK_INVALID_PUBKEY + ret );

    if( ( ret = mbedtls_rsa_import_raw( rsa, NULL, 0, NULL, 0, NULL, 0,

                                        NULL, 0, *p, len ) ) != 0 )

        return( MBEDTLS_ERR_PK_INVALID_PUBKEY );

    *p += len;

    if( mbedtls_rsa_complete( rsa ) != 0 ||

        mbedtls_rsa_check_pubkey( rsa ) != 0 )

    {

        return( MBEDTLS_ERR_PK_INVALID_PUBKEY );

    }

    if( *p != end )

        return( MBEDTLS_ERR_PK_INVALID_PUBKEY +

                MBEDTLS_ERR_ASN1_LENGTH_MISMATCH );

    return( 0 );

}

#endif /* MBEDTLS_RSA_C */

/* Get a PK algorithm identifier

 *

 *  AlgorithmIdentifier  ::=  SEQUENCE  {

 *       algorithm               OBJECT IDENTIFIER,

 *       parameters              ANY DEFINED BY algorithm OPTIONAL  }

 */

static int pk_get_pk_alg( unsigned char **p,

                          const unsigned char *end,

                          mbedtls_pk_type_t *pk_alg, mbedtls_asn1_buf *params )

{

    int ret;

    mbedtls_asn1_buf alg_oid;

    memset( params, 0, sizeof(mbedtls_asn1_buf) );

    if( ( ret = mbedtls_asn1_get_alg( p, end, &alg_oid, params ) ) != 0 )

        return( MBEDTLS_ERR_PK_INVALID_ALG + ret );

    if( mbedtls_oid_get_pk_alg( &alg_oid, pk_alg ) != 0 )

        return( MBEDTLS_ERR_PK_UNKNOWN_PK_ALG );

    /*

     * No parameters with RSA (only for EC)

     */

    if( *pk_alg == MBEDTLS_PK_RSA &&

            ( ( params->tag != MBEDTLS_ASN1_NULL && params->tag != 0 ) ||

                params->len != 0 ) )

    {

        return( MBEDTLS_ERR_PK_INVALID_ALG );

    }

    return( 0 );

}

/*

 *  SubjectPublicKeyInfo  ::=  SEQUENCE  {

 *       algorithm            AlgorithmIdentifier,

 *       subjectPublicKey     BIT STRING }

 */

int mbedtls_pk_parse_subpubkey( unsigned char **p, const unsigned char *end,

                        mbedtls_pk_context *pk )

{

    int ret;

    size_t len;

    mbedtls_asn1_buf alg_params;

    mbedtls_pk_type_t pk_alg = MBEDTLS_PK_NONE;

    const mbedtls_pk_info_t *pk_info;

    PK_VALIDATE_RET( p != NULL );

    PK_VALIDATE_RET( *p != NULL );

    PK_VALIDATE_RET( end != NULL );

    PK_VALIDATE_RET( pk != NULL );

    if( ( ret = mbedtls_asn1_get_tag( p, end, &len,

                    MBEDTLS_ASN1_CONSTRUCTED | MBEDTLS_ASN1_SEQUENCE ) ) != 0 )

    {

        return( MBEDTLS_ERR_PK_KEY_INVALID_FORMAT + ret );

    }

    end = *p + len;

    if( ( ret = pk_get_pk_alg( p, end, &pk_alg, &alg_params ) ) != 0 )

        return( ret );

    if( ( ret = mbedtls_asn1_get_bitstring_null( p, end, &len ) ) != 0 )

        return( MBEDTLS_ERR_PK_INVALID_PUBKEY + ret );

    if( *p + len != end )

        return( MBEDTLS_ERR_PK_INVALID_PUBKEY +

                MBEDTLS_ERR_ASN1_LENGTH_MISMATCH );

    if( ( pk_info = mbedtls_pk_info_from_type( pk_alg ) ) == NULL )

        return( MBEDTLS_ERR_PK_UNKNOWN_PK_ALG );

    if( ( ret = mbedtls_pk_setup( pk, pk_info ) ) != 0 )

        return( ret );

#if defined(MBEDTLS_RSA_C)

    if( pk_alg == MBEDTLS_PK_RSA )

    {

        ret = pk_get_rsapubkey( p, end, mbedtls_pk_rsa( *pk ) );

    } else

#endif /* MBEDTLS_RSA_C */

#if defined(MBEDTLS_ECP_C)

    if( pk_alg == MBEDTLS_PK_ECKEY_DH || pk_alg == MBEDTLS_PK_ECKEY )

    {

        ret = pk_use_ecparams( &alg_params, &mbedtls_pk_ec( *pk )->grp );

        if( ret == 0 )

            ret = pk_get_ecpubkey( p, end, mbedtls_pk_ec( *pk ) );

    } else

#endif /* MBEDTLS_ECP_C */

        ret = MBEDTLS_ERR_PK_UNKNOWN_PK_ALG;

    if( ret == 0 && *p != end )

        ret = MBEDTLS_ERR_PK_INVALID_PUBKEY

              MBEDTLS_ERR_ASN1_LENGTH_MISMATCH;

    if( ret != 0 )

        mbedtls_pk_free( pk );

    return( ret );

}

#if defined(MBEDTLS_RSA_C)

/*

 * Wrapper around mbedtls_asn1_get_mpi() that rejects zero.

 *

 * The value zero is:

 * - never a valid value for an RSA parameter

 * - interpreted as "omitted, please reconstruct" by mbedtls_rsa_complete().

 *

 * Since values can't be omitted in PKCS#1, passing a zero value to

 * rsa_complete() would be incorrect, so reject zero values early.

 */

static int asn1_get_nonzero_mpi( unsigned char **p,

                                 const unsigned char *end,

                                 mbedtls_mpi *X )

{

    int ret;

    ret = mbedtls_asn1_get_mpi( p, end, X );

    if( ret != 0 )

        return( ret );

    if( mbedtls_mpi_cmp_int( X, 0 ) == 0 )

        return( MBEDTLS_ERR_PK_KEY_INVALID_FORMAT );

    return( 0 );

}

/*

 * Parse a PKCS#1 encoded private RSA key

 */

static int pk_parse_key_pkcs1_der( mbedtls_rsa_context *rsa,

                                   const unsigned char *key,

                                   size_t keylen )

{

    int ret, version;

    size_t len;

    unsigned char *p, *end;

    mbedtls_mpi T;

    mbedtls_mpi_init( &T );

    p = (unsigned char *) key;

    end = p + keylen;

    /*

     * This function parses the RSAPrivateKey (PKCS#1)

     *

     *  RSAPrivateKey ::= SEQUENCE {

     *      version           Version,

     *      modulus           INTEGER,  -- n

     *      publicExponent    INTEGER,  -- e

     *      privateExponent   INTEGER,  -- d

     *      prime1            INTEGER,  -- p

     *      prime2            INTEGER,  -- q

     *      exponent1         INTEGER,  -- d mod (p-1)

     *      exponent2         INTEGER,  -- d mod (q-1)

     *      coefficient       INTEGER,  -- (inverse of q) mod p

     *      otherPrimeInfos   OtherPrimeInfos OPTIONAL

     *  }

     */

    if( ( ret = mbedtls_asn1_get_tag( &p, end, &len,

            MBEDTLS_ASN1_CONSTRUCTED | MBEDTLS_ASN1_SEQUENCE ) ) != 0 )

    {

        return( MBEDTLS_ERR_PK_KEY_INVALID_FORMAT + ret );

    }

    end = p + len;

    if( ( ret = mbedtls_asn1_get_int( &p, end, &version ) ) != 0 )

    {

        return( MBEDTLS_ERR_PK_KEY_INVALID_FORMAT + ret );

    }

    if( version != 0 )

    {

        return( MBEDTLS_ERR_PK_KEY_INVALID_VERSION );

    }

    /* Import N */

    if( ( ret = asn1_get_nonzero_mpi( &p, end, &T ) ) != 0 ||

        ( ret = mbedtls_rsa_import( rsa, &T, NULL, NULL,

                                        NULL, NULL ) ) != 0 )

        goto cleanup;

    /* Import E */

    if( ( ret = asn1_get_nonzero_mpi( &p, end, &T ) ) != 0 ||

        ( ret = mbedtls_rsa_import( rsa, NULL, NULL, NULL,

                                        NULL, &T ) ) != 0 )

        goto cleanup;

    /* Import D */

    if( ( ret = asn1_get_nonzero_mpi( &p, end, &T ) ) != 0 ||

        ( ret = mbedtls_rsa_import( rsa, NULL, NULL, NULL,

                                        &T, NULL ) ) != 0 )

        goto cleanup;

    /* Import P */

    if( ( ret = asn1_get_nonzero_mpi( &p, end, &T ) ) != 0 ||

        ( ret = mbedtls_rsa_import( rsa, NULL, &T, NULL,

                                        NULL, NULL ) ) != 0 )

        goto cleanup;

    /* Import Q */

    if( ( ret = asn1_get_nonzero_mpi( &p, end, &T ) ) != 0 ||

        ( ret = mbedtls_rsa_import( rsa, NULL, NULL, &T,

                                        NULL, NULL ) ) != 0 )

        goto cleanup;

#if !defined(MBEDTLS_RSA_NO_CRT) && !defined(MBEDTLS_RSA_ALT)

    /*

    * The RSA CRT parameters DP, DQ and QP are nominally redundant, in

    * that they can be easily recomputed from D, P and Q. However by

    * parsing them from the PKCS1 structure it is possible to avoid

    * recalculating them which both reduces the overhead of loading

    * RSA private keys into memory and also avoids side channels which

    * can arise when computing those values, since all of D, P, and Q

    * are secret. See https://eprint.iacr.org/2020/055 for a

    * description of one such attack.

    */

    /* Import DP */

    if( ( ret = asn1_get_nonzero_mpi( &p, end, &T ) ) != 0 ||

        ( ret = mbedtls_mpi_copy( &rsa->DP, &T ) ) != 0 )

       goto cleanup;

    /* Import DQ */

    if( ( ret = asn1_get_nonzero_mpi( &p, end, &T ) ) != 0 ||

        ( ret = mbedtls_mpi_copy( &rsa->DQ, &T ) ) != 0 )

       goto cleanup;

    /* Import QP */

    if( ( ret = asn1_get_nonzero_mpi( &p, end, &T ) ) != 0 ||

        ( ret = mbedtls_mpi_copy( &rsa->QP, &T ) ) != 0 )

       goto cleanup;

#else

    /* Verify existance of the CRT params */

    if( ( ret = asn1_get_nonzero_mpi( &p, end, &T ) ) != 0 ||

        ( ret = asn1_get_nonzero_mpi( &p, end, &T ) ) != 0 ||

        ( ret = asn1_get_nonzero_mpi( &p, end, &T ) ) != 0 )

       goto cleanup;

#endif

    /* rsa_complete() doesn't complete anything with the default

     * implementation but is still called:

     * - for the benefit of alternative implementation that may want to

     *   pre-compute stuff beyond what's provided (eg Montgomery factors)

     * - as is also sanity-checks the key

     *

     * Furthermore, we also check the public part for consistency with

     * mbedtls_pk_parse_pubkey(), as it includes size minima for example.

     */

    if( ( ret = mbedtls_rsa_complete( rsa ) ) != 0 ||

        ( ret = mbedtls_rsa_check_pubkey( rsa ) ) != 0 )

    {

        goto cleanup;

    }

    if( p != end )

    {

        ret = MBEDTLS_ERR_PK_KEY_INVALID_FORMAT +

              MBEDTLS_ERR_ASN1_LENGTH_MISMATCH ;

    }

cleanup:

    mbedtls_mpi_free( &T );

    if( ret != 0 )

    {

        /* Wrap error code if it's coming from a lower level */

        if( ( ret & 0xff80 ) == 0 )

            ret = MBEDTLS_ERR_PK_KEY_INVALID_FORMAT + ret;

        else

            ret = MBEDTLS_ERR_PK_KEY_INVALID_FORMAT;

        mbedtls_rsa_free( rsa );

    }

    return( ret );

}

#endif /* MBEDTLS_RSA_C */

#if defined(MBEDTLS_ECP_C)

/*

 * Parse a SEC1 encoded private EC key

 */

static int pk_parse_key_sec1_der( mbedtls_ecp_keypair *eck,

                                  const unsigned char *key,

                                  size_t keylen )

{

    int ret;

    int version, pubkey_done;

    size_t len;

    mbedtls_asn1_buf params;

    unsigned char *p = (unsigned char *) key;

    unsigned char *end = p + keylen;

    unsigned char *end2;

    /*

     * RFC 5915, or SEC1 Appendix C.4

     *

     * ECPrivateKey ::= SEQUENCE {

     *      version        INTEGER { ecPrivkeyVer1(1) } (ecPrivkeyVer1),

     *      privateKey     OCTET STRING,

     *      parameters [0] ECParameters {{ NamedCurve }} OPTIONAL,

     *      publicKey  [1] BIT STRING OPTIONAL

     *    }

     */

    if( ( ret = mbedtls_asn1_get_tag( &p, end, &len,

            MBEDTLS_ASN1_CONSTRUCTED | MBEDTLS_ASN1_SEQUENCE ) ) != 0 )

    {

        return( MBEDTLS_ERR_PK_KEY_INVALID_FORMAT + ret );

    }

    end = p + len;

    if( ( ret = mbedtls_asn1_get_int( &p, end, &version ) ) != 0 )

        return( MBEDTLS_ERR_PK_KEY_INVALID_FORMAT + ret );

    if( version != 1 )

        return( MBEDTLS_ERR_PK_KEY_INVALID_VERSION );

    if( ( ret = mbedtls_asn1_get_tag( &p, end, &len, MBEDTLS_ASN1_OCTET_STRING ) ) != 0 )

        return( MBEDTLS_ERR_PK_KEY_INVALID_FORMAT + ret );

    if( ( ret = mbedtls_mpi_read_binary( &eck->d, p, len ) ) != 0 )

    {

        mbedtls_ecp_keypair_free( eck );

        return( MBEDTLS_ERR_PK_KEY_INVALID_FORMAT + ret );

    }

    p += len;

    pubkey_done = 0;

    if( p != end )

    {

        /*

         * Is 'parameters' present?

         */

        if( ( ret = mbedtls_asn1_get_tag( &p, end, &len,

                        MBEDTLS_ASN1_CONTEXT_SPECIFIC | MBEDTLS_ASN1_CONSTRUCTED | 0 ) ) == 0 )

        {

            if( ( ret = pk_get_ecparams( &p, p + len, ¶ms) ) != 0 ||

                ( ret = pk_use_ecparams( ¶ms, &eck->grp )  ) != 0 )

            {

                mbedtls_ecp_keypair_free( eck );

                return( ret );

            }

        }

        else if( ret != MBEDTLS_ERR_ASN1_UNEXPECTED_TAG )

        {

            mbedtls_ecp_keypair_free( eck );

            return( MBEDTLS_ERR_PK_KEY_INVALID_FORMAT + ret );

        }

    }

    if( p != end )

    {

        /*

         * Is 'publickey' present? If not, or if we can't read it (eg because it

         * is compressed), create it from the private key.

         */

        if( ( ret = mbedtls_asn1_get_tag( &p, end, &len,

                        MBEDTLS_ASN1_CONTEXT_SPECIFIC | MBEDTLS_ASN1_CONSTRUCTED | 1 ) ) == 0 )

        {

            end2 = p + len;

            if( ( ret = mbedtls_asn1_get_bitstring_null( &p, end2, &len ) ) != 0 )

                return( MBEDTLS_ERR_PK_KEY_INVALID_FORMAT + ret );

            if( p + len != end2 )

                return( MBEDTLS_ERR_PK_KEY_INVALID_FORMAT +

                        MBEDTLS_ERR_ASN1_LENGTH_MISMATCH );

            if( ( ret = pk_get_ecpubkey( &p, end2, eck ) ) == 0 )

                pubkey_done = 1;

            else

            {

                /*

                 * The only acceptable failure mode of pk_get_ecpubkey() above

                 * is if the point format is not recognized.

                 */

                if( ret != MBEDTLS_ERR_ECP_FEATURE_UNAVAILABLE )

                    return( MBEDTLS_ERR_PK_KEY_INVALID_FORMAT );

            }

        }

        else if( ret != MBEDTLS_ERR_ASN1_UNEXPECTED_TAG )

        {

            mbedtls_ecp_keypair_free( eck );

            return( MBEDTLS_ERR_PK_KEY_INVALID_FORMAT + ret );

        }

    }

    if( ! pubkey_done &&

        ( ret = mbedtls_ecp_mul( &eck->grp, &eck->Q, &eck->d, &eck->grp.G,

                                                      NULL, NULL ) ) != 0 )

    {

        mbedtls_ecp_keypair_free( eck );

        return( MBEDTLS_ERR_PK_KEY_INVALID_FORMAT + ret );

    }

    if( ( ret = mbedtls_ecp_check_privkey( &eck->grp, &eck->d ) ) != 0 )

    {

        mbedtls_ecp_keypair_free( eck );

        return( ret );

    }

    return( 0 );

}

#endif /* MBEDTLS_ECP_C */

/*

 * Parse an unencrypted PKCS#8 encoded private key

 *

 * Notes:

 *

 * - This function does not own the key buffer. It is the

 *   responsibility of the caller to take care of zeroizing

 *   and freeing it after use.

 *

 * - The function is responsible for freeing the provided

 *   PK context on failure.

 *

 */

static int pk_parse_key_pkcs8_unencrypted_der(

                                    mbedtls_pk_context *pk,

                                    const unsigned char* key,

                                    size_t keylen )

{

    int ret, version;

    size_t len;

    mbedtls_asn1_buf params;

    unsigned char *p = (unsigned char *) key;

    unsigned char *end = p + keylen;

    mbedtls_pk_type_t pk_alg = MBEDTLS_PK_NONE;

    const mbedtls_pk_info_t *pk_info;

    /*

     * This function parses the PrivateKeyInfo object (PKCS#8 v1.2 = RFC 5208)

     *

     *    PrivateKeyInfo ::= SEQUENCE {

     *      version                   Version,

     *      privateKeyAlgorithm       PrivateKeyAlgorithmIdentifier,

     *      privateKey                PrivateKey,

     *      attributes           [0]  IMPLICIT Attributes OPTIONAL }

     *

     *    Version ::= INTEGER

     *    PrivateKeyAlgorithmIdentifier ::= AlgorithmIdentifier

     *    PrivateKey ::= OCTET STRING

     *

     *  The PrivateKey OCTET STRING is a SEC1 ECPrivateKey

     */

    if( ( ret = mbedtls_asn1_get_tag( &p, end, &len,

            MBEDTLS_ASN1_CONSTRUCTED | MBEDTLS_ASN1_SEQUENCE ) ) != 0 )

    {

        return( MBEDTLS_ERR_PK_KEY_INVALID_FORMAT + ret );

    }

    end = p + len;

    if( ( ret = mbedtls_asn1_get_int( &p, end, &version ) ) != 0 )

        return( MBEDTLS_ERR_PK_KEY_INVALID_FORMAT + ret );

    if( version != 0 )

        return( MBEDTLS_ERR_PK_KEY_INVALID_VERSION + ret );

    if( ( ret = pk_get_pk_alg( &p, end, &pk_alg, ¶ms ) ) != 0 )

        return( MBEDTLS_ERR_PK_KEY_INVALID_FORMAT + ret );

    if( ( ret = mbedtls_asn1_get_tag( &p, end, &len, MBEDTLS_ASN1_OCTET_STRING ) ) != 0 )

        return( MBEDTLS_ERR_PK_KEY_INVALID_FORMAT + ret );

    if( len < 1 )

        return( MBEDTLS_ERR_PK_KEY_INVALID_FORMAT +

                MBEDTLS_ERR_ASN1_OUT_OF_DATA );

    if( ( pk_info = mbedtls_pk_info_from_type( pk_alg ) ) == NULL )

        return( MBEDTLS_ERR_PK_UNKNOWN_PK_ALG );

    if( ( ret = mbedtls_pk_setup( pk, pk_info ) ) != 0 )

        return( ret );

#if defined(MBEDTLS_RSA_C)

    if( pk_alg == MBEDTLS_PK_RSA )

    {

        if( ( ret = pk_parse_key_pkcs1_der( mbedtls_pk_rsa( *pk ), p, len ) ) != 0 )

        {

            mbedtls_pk_free( pk );

            return( ret );

        }

    } else

#endif /* MBEDTLS_RSA_C */

#if defined(MBEDTLS_ECP_C)

    if( pk_alg == MBEDTLS_PK_ECKEY || pk_alg == MBEDTLS_PK_ECKEY_DH )

    {

        if( ( ret = pk_use_ecparams( ¶ms, &mbedtls_pk_ec( *pk )->grp ) ) != 0 ||

            ( ret = pk_parse_key_sec1_der( mbedtls_pk_ec( *pk ), p, len )  ) != 0 )

        {

            mbedtls_pk_free( pk );

            return( ret );

        }

    } else

#endif /* MBEDTLS_ECP_C */

        return( MBEDTLS_ERR_PK_UNKNOWN_PK_ALG );

    return( 0 );

}

/*

 * Parse an encrypted PKCS#8 encoded private key

 *

 * To save space, the decryption happens in-place on the given key buffer.

 * Also, while this function may modify the keybuffer, it doesn't own it,

 * and instead it is the responsibility of the caller to zeroize and properly

 * free it after use.

 *

 */

#if defined(MBEDTLS_PKCS12_C) || defined(MBEDTLS_PKCS5_C)

static int pk_parse_key_pkcs8_encrypted_der(

                                    mbedtls_pk_context *pk,

                                    unsigned char *key, size_t keylen,

                                    const unsigned char *pwd, size_t pwdlen )

{

    int ret, decrypted = 0;

    size_t len;

    unsigned char *buf;

    unsigned char *p, *end;

    mbedtls_asn1_buf pbe_alg_oid, pbe_params;

#if defined(MBEDTLS_PKCS12_C)

    mbedtls_cipher_type_t cipher_alg;

    mbedtls_md_type_t md_alg;

#endif

    p = key;

    end = p + keylen;

    if( pwdlen == 0 )

        return( MBEDTLS_ERR_PK_PASSWORD_REQUIRED );

    /*

     * This function parses the EncryptedPrivateKeyInfo object (PKCS#8)

     *

     *  EncryptedPrivateKeyInfo ::= SEQUENCE {

     *    encryptionAlgorithm  EncryptionAlgorithmIdentifier,

     *    encryptedData        EncryptedData

     *  }

     *