/* * Public Key layer for parsing key files and structures * * Copyright (C) 2006-2014, ARM Limited, All Rights Reserved * * This file is part of mbed TLS (https://tls.mbed.org) * * 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. */ #if !defined(POLARSSL_CONFIG_FILE) #include "polarssl/config.h" #else #include POLARSSL_CONFIG_FILE #endif #if defined(POLARSSL_PK_PARSE_C) #include "polarssl/pk.h" #include "polarssl/asn1.h" #include "polarssl/oid.h" #include #if defined(POLARSSL_RSA_C) #include "polarssl/rsa.h" #endif #if defined(POLARSSL_ECP_C) #include "polarssl/ecp.h" #endif #if defined(POLARSSL_ECDSA_C) #include "polarssl/ecdsa.h" #endif #if defined(POLARSSL_PEM_PARSE_C) #include "polarssl/pem.h" #endif #if defined(POLARSSL_PKCS5_C) #include "polarssl/pkcs5.h" #endif #if defined(POLARSSL_PKCS12_C) #include "polarssl/pkcs12.h" #endif #if defined(POLARSSL_PLATFORM_C) #include "polarssl/platform.h" #else #include #define polarssl_malloc malloc #define polarssl_free free #endif #if defined(POLARSSL_FS_IO) || \ defined(POLARSSL_PKCS12_C) || defined(POLARSSL_PKCS5_C) /* Implementation that should never be optimized out by the compiler */ static void polarssl_zeroize( void *v, size_t n ) { volatile unsigned char *p = v; while( n-- ) *p++ = 0; } #endif #if defined(POLARSSL_FS_IO) /* * Load all data from a file into a given buffer. */ int pk_load_file( const char *path, unsigned char **buf, size_t *n ) { FILE *f; long size; if( ( f = fopen( path, "rb" ) ) == NULL ) return( POLARSSL_ERR_PK_FILE_IO_ERROR ); fseek( f, 0, SEEK_END ); if( ( size = ftell( f ) ) == -1 ) { fclose( f ); return( POLARSSL_ERR_PK_FILE_IO_ERROR ); } fseek( f, 0, SEEK_SET ); *n = (size_t) size; if( *n + 1 == 0 || ( *buf = polarssl_malloc( *n + 1 ) ) == NULL ) { fclose( f ); return( POLARSSL_ERR_PK_MALLOC_FAILED ); } if( fread( *buf, 1, *n, f ) != *n ) { fclose( f ); polarssl_free( *buf ); return( POLARSSL_ERR_PK_FILE_IO_ERROR ); } fclose( f ); (*buf)[*n] = '\0'; return( 0 ); } /* * Load and parse a private key */ int pk_parse_keyfile( pk_context *ctx, const char *path, const char *pwd ) { int ret; size_t n; unsigned char *buf; if( ( ret = pk_load_file( path, &buf, &n ) ) != 0 ) return( ret ); if( pwd == NULL ) ret = pk_parse_key( ctx, buf, n, NULL, 0 ); else ret = pk_parse_key( ctx, buf, n, (const unsigned char *) pwd, strlen( pwd ) ); polarssl_zeroize( buf, n + 1 ); polarssl_free( buf ); return( ret ); } /* * Load and parse a public key */ int pk_parse_public_keyfile( pk_context *ctx, const char *path ) { int ret; size_t n; unsigned char *buf; if( ( ret = pk_load_file( path, &buf, &n ) ) != 0 ) return( ret ); ret = pk_parse_public_key( ctx, buf, n ); polarssl_zeroize( buf, n + 1 ); polarssl_free( buf ); return( ret ); } #endif /* POLARSSL_FS_IO */ #if defined(POLARSSL_ECP_C) /* Minimally parse an ECParameters buffer to and asn1_buf * * ECParameters ::= CHOICE { * namedCurve OBJECT IDENTIFIER * specifiedCurve SpecifiedECDomain -- = SEQUENCE { ... } * -- implicitCurve NULL * } */ static int pk_get_ecparams( unsigned char **p, const unsigned char *end, asn1_buf *params ) { int ret; /* Tag may be either OID or SEQUENCE */ params->tag = **p; if( params->tag != ASN1_OID #if defined(POLARSSL_PK_PARSE_EC_EXTENDED) && params->tag != ( ASN1_CONSTRUCTED | ASN1_SEQUENCE ) #endif ) { return( POLARSSL_ERR_PK_KEY_INVALID_FORMAT + POLARSSL_ERR_ASN1_UNEXPECTED_TAG ); } if( ( ret = asn1_get_tag( p, end, ¶ms->len, params->tag ) ) != 0 ) { return( POLARSSL_ERR_PK_KEY_INVALID_FORMAT + ret ); } params->p = *p; *p += params->len; if( *p != end ) return( POLARSSL_ERR_PK_KEY_INVALID_FORMAT + POLARSSL_ERR_ASN1_LENGTH_MISMATCH ); return( 0 ); } #if defined(POLARSSL_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 asn1_buf *params, 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 = asn1_get_int( &p, end, &ver ) ) != 0 ) return( POLARSSL_ERR_PK_KEY_INVALID_FORMAT + ret ); if( ver < 1 || ver > 3 ) return( POLARSSL_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 = asn1_get_tag( &p, end, &len, ASN1_CONSTRUCTED | 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 = asn1_get_tag( &p, end_field, &len, ASN1_OID ) ) != 0 ) return( ret ); if( len != OID_SIZE( OID_ANSI_X9_62_PRIME_FIELD ) || memcmp( p, OID_ANSI_X9_62_PRIME_FIELD, len ) != 0 ) { return( POLARSSL_ERR_PK_FEATURE_UNAVAILABLE ); } p += len; /* Prime-p ::= INTEGER -- Field of size p. */ if( ( ret = asn1_get_mpi( &p, end_field, &grp->P ) ) != 0 ) return( POLARSSL_ERR_PK_KEY_INVALID_FORMAT + ret ); grp->pbits = mpi_msb( &grp->P ); if( p != end_field ) return( POLARSSL_ERR_PK_KEY_INVALID_FORMAT + POLARSSL_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 = asn1_get_tag( &p, end, &len, ASN1_CONSTRUCTED | ASN1_SEQUENCE ) ) != 0 ) return( ret ); end_curve = p + len; /* * FieldElement ::= OCTET STRING * containing an integer in the case of a prime field */ if( ( ret = asn1_get_tag( &p, end_curve, &len, ASN1_OCTET_STRING ) ) != 0 || ( ret = mpi_read_binary( &grp->A, p, len ) ) != 0 ) { return( POLARSSL_ERR_PK_KEY_INVALID_FORMAT + ret ); } p += len; if( ( ret = asn1_get_tag( &p, end_curve, &len, ASN1_OCTET_STRING ) ) != 0 || ( ret = mpi_read_binary( &grp->B, p, len ) ) != 0 ) { return( POLARSSL_ERR_PK_KEY_INVALID_FORMAT + ret ); } p += len; /* Ignore seed BIT STRING OPTIONAL */ if( ( ret = asn1_get_tag( &p, end_curve, &len, ASN1_BIT_STRING ) ) == 0 ) p += len; if( p != end_curve ) return( POLARSSL_ERR_PK_KEY_INVALID_FORMAT + POLARSSL_ERR_ASN1_LENGTH_MISMATCH ); /* * ECPoint ::= OCTET STRING */ if( ( ret = asn1_get_tag( &p, end, &len, ASN1_OCTET_STRING ) ) != 0 ) return( POLARSSL_ERR_PK_KEY_INVALID_FORMAT + ret ); if( ( ret = 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 != POLARSSL_ERR_ECP_FEATURE_UNAVAILABLE || ( p[0] != 0x02 && p[0] != 0x03 ) || len != mpi_size( &grp->P ) + 1 || mpi_read_binary( &grp->G.X, p + 1, len - 1 ) != 0 || mpi_lset( &grp->G.Y, p[0] - 2 ) != 0 || mpi_lset( &grp->G.Z, 1 ) != 0 ) { return( POLARSSL_ERR_PK_KEY_INVALID_FORMAT ); } } p += len; /* * order INTEGER */ if( ( ret = asn1_get_mpi( &p, end, &grp->N ) ) != 0 ) return( POLARSSL_ERR_PK_KEY_INVALID_FORMAT + ret ); grp->nbits = mpi_msb( &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 ecp_group *grp, ecp_group_id *grp_id ) { int ret = 0; ecp_group ref; const ecp_group_id *id; ecp_group_init( &ref ); for( id = ecp_grp_id_list(); *id != POLARSSL_ECP_DP_NONE; id++ ) { /* Load the group associated to that id */ ecp_group_free( &ref ); MPI_CHK( ecp_use_known_dp( &ref, *id ) ); /* Compare to the group we were given, starting with easy tests */ if( grp->pbits == ref.pbits && grp->nbits == ref.nbits && mpi_cmp_mpi( &grp->P, &ref.P ) == 0 && mpi_cmp_mpi( &grp->A, &ref.A ) == 0 && mpi_cmp_mpi( &grp->B, &ref.B ) == 0 && mpi_cmp_mpi( &grp->N, &ref.N ) == 0 && mpi_cmp_mpi( &grp->G.X, &ref.G.X ) == 0 && mpi_cmp_mpi( &grp->G.Z, &ref.G.Z ) == 0 && /* For Y we may only know the parity bit, so compare only that */ mpi_get_bit( &grp->G.Y, 0 ) == mpi_get_bit( &ref.G.Y, 0 ) ) { break; } } cleanup: ecp_group_free( &ref ); *grp_id = *id; if( ret == 0 && *id == POLARSSL_ECP_DP_NONE ) ret = POLARSSL_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 asn1_buf *params, ecp_group_id *grp_id ) { int ret; ecp_group grp; 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: ecp_group_free( &grp ); return( ret ); } #endif /* POLARSSL_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 asn1_buf *params, ecp_group *grp ) { int ret; ecp_group_id grp_id; if( params->tag == ASN1_OID ) { if( oid_get_ec_grp( params, &grp_id ) != 0 ) return( POLARSSL_ERR_PK_UNKNOWN_NAMED_CURVE ); } else { #if defined(POLARSSL_PK_PARSE_EC_EXTENDED) if( ( ret = pk_group_id_from_specified( params, &grp_id ) ) != 0 ) return( ret ); #else return( POLARSSL_ERR_PK_KEY_INVALID_FORMAT ); #endif } /* * grp may already be initilialized; if so, make sure IDs match */ if( grp->id != POLARSSL_ECP_DP_NONE && grp->id != grp_id ) return( POLARSSL_ERR_PK_KEY_INVALID_FORMAT ); if( ( ret = ecp_use_known_dp( 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 ecp_point_read_binary() and leave p in a usable state. */ static int pk_get_ecpubkey( unsigned char **p, const unsigned char *end, ecp_keypair *key ) { int ret; if( ( ret = ecp_point_read_binary( &key->grp, &key->Q, (const unsigned char *) *p, end - *p ) ) == 0 ) { ret = ecp_check_pubkey( &key->grp, &key->Q ); } /* * We know ecp_point_read_binary consumed all bytes or failed */ *p = (unsigned char *) end; return( ret ); } #endif /* POLARSSL_ECP_C */ #if defined(POLARSSL_RSA_C) /* * RSAPublicKey ::= SEQUENCE { * modulus INTEGER, -- n * publicExponent INTEGER -- e * } */ static int pk_get_rsapubkey( unsigned char **p, const unsigned char *end, rsa_context *rsa ) { int ret; size_t len; if( ( ret = asn1_get_tag( p, end, &len, ASN1_CONSTRUCTED | ASN1_SEQUENCE ) ) != 0 ) return( POLARSSL_ERR_PK_INVALID_PUBKEY + ret ); if( *p + len != end ) return( POLARSSL_ERR_PK_INVALID_PUBKEY + POLARSSL_ERR_ASN1_LENGTH_MISMATCH ); if( ( ret = asn1_get_mpi( p, end, &rsa->N ) ) != 0 || ( ret = asn1_get_mpi( p, end, &rsa->E ) ) != 0 ) return( POLARSSL_ERR_PK_INVALID_PUBKEY + ret ); if( *p != end ) return( POLARSSL_ERR_PK_INVALID_PUBKEY + POLARSSL_ERR_ASN1_LENGTH_MISMATCH ); if( ( ret = rsa_check_pubkey( rsa ) ) != 0 ) return( POLARSSL_ERR_PK_INVALID_PUBKEY ); rsa->len = mpi_size( &rsa->N ); return( 0 ); } #endif /* POLARSSL_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, pk_type_t *pk_alg, asn1_buf *params ) { int ret; asn1_buf alg_oid; memset( params, 0, sizeof(asn1_buf) ); if( ( ret = asn1_get_alg( p, end, &alg_oid, params ) ) != 0 ) return( POLARSSL_ERR_PK_INVALID_ALG + ret ); if( oid_get_pk_alg( &alg_oid, pk_alg ) != 0 ) return( POLARSSL_ERR_PK_UNKNOWN_PK_ALG ); /* * No parameters with RSA (only for EC) */ if( *pk_alg == POLARSSL_PK_RSA && ( ( params->tag != ASN1_NULL && params->tag != 0 ) || params->len != 0 ) ) { return( POLARSSL_ERR_PK_INVALID_ALG ); } return( 0 ); } /* * SubjectPublicKeyInfo ::= SEQUENCE { * algorithm AlgorithmIdentifier, * subjectPublicKey BIT STRING } */ int pk_parse_subpubkey( unsigned char **p, const unsigned char *end, pk_context *pk ) { int ret; size_t len; asn1_buf alg_params; pk_type_t pk_alg = POLARSSL_PK_NONE; const pk_info_t *pk_info; if( ( ret = asn1_get_tag( p, end, &len, ASN1_CONSTRUCTED | ASN1_SEQUENCE ) ) != 0 ) { return( POLARSSL_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 = asn1_get_bitstring_null( p, end, &len ) ) != 0 ) return( POLARSSL_ERR_PK_INVALID_PUBKEY + ret ); if( *p + len != end ) return( POLARSSL_ERR_PK_INVALID_PUBKEY + POLARSSL_ERR_ASN1_LENGTH_MISMATCH ); if( ( pk_info = pk_info_from_type( pk_alg ) ) == NULL ) return( POLARSSL_ERR_PK_UNKNOWN_PK_ALG ); if( ( ret = pk_init_ctx( pk, pk_info ) ) != 0 ) return( ret ); #if defined(POLARSSL_RSA_C) if( pk_alg == POLARSSL_PK_RSA ) { ret = pk_get_rsapubkey( p, end, pk_rsa( *pk ) ); } else #endif /* POLARSSL_RSA_C */ #if defined(POLARSSL_ECP_C) if( pk_alg == POLARSSL_PK_ECKEY_DH || pk_alg == POLARSSL_PK_ECKEY ) { ret = pk_use_ecparams( &alg_params, &pk_ec( *pk )->grp ); if( ret == 0 ) ret = pk_get_ecpubkey( p, end, pk_ec( *pk ) ); } else #endif /* POLARSSL_ECP_C */ ret = POLARSSL_ERR_PK_UNKNOWN_PK_ALG; if( ret == 0 && *p != end ) ret = POLARSSL_ERR_PK_INVALID_PUBKEY POLARSSL_ERR_ASN1_LENGTH_MISMATCH; if( ret != 0 ) pk_free( pk ); return( ret ); } #if defined(POLARSSL_RSA_C) /* * Parse a PKCS#1 encoded private RSA key */ static int pk_parse_key_pkcs1_der( rsa_context *rsa, const unsigned char *key, size_t keylen ) { int ret; size_t len; unsigned char *p, *end; 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 = asn1_get_tag( &p, end, &len, ASN1_CONSTRUCTED | ASN1_SEQUENCE ) ) != 0 ) { return( POLARSSL_ERR_PK_KEY_INVALID_FORMAT + ret ); } end = p + len; if( ( ret = asn1_get_int( &p, end, &rsa->ver ) ) != 0 ) { return( POLARSSL_ERR_PK_KEY_INVALID_FORMAT + ret ); } if( rsa->ver != 0 ) { return( POLARSSL_ERR_PK_KEY_INVALID_VERSION ); } if( ( ret = asn1_get_mpi( &p, end, &rsa->N ) ) != 0 || ( ret = asn1_get_mpi( &p, end, &rsa->E ) ) != 0 || ( ret = asn1_get_mpi( &p, end, &rsa->D ) ) != 0 || ( ret = asn1_get_mpi( &p, end, &rsa->P ) ) != 0 || ( ret = asn1_get_mpi( &p, end, &rsa->Q ) ) != 0 || ( ret = asn1_get_mpi( &p, end, &rsa->DP ) ) != 0 || ( ret = asn1_get_mpi( &p, end, &rsa->DQ ) ) != 0 || ( ret = asn1_get_mpi( &p, end, &rsa->QP ) ) != 0 ) { rsa_free( rsa ); return( POLARSSL_ERR_PK_KEY_INVALID_FORMAT + ret ); } rsa->len = mpi_size( &rsa->N ); if( p != end ) { rsa_free( rsa ); return( POLARSSL_ERR_PK_KEY_INVALID_FORMAT + POLARSSL_ERR_ASN1_LENGTH_MISMATCH ); } if( ( ret = rsa_check_privkey( rsa ) ) != 0 ) { rsa_free( rsa ); return( ret ); } return( 0 ); } #endif /* POLARSSL_RSA_C */ #if defined(POLARSSL_ECP_C) /* * Parse a SEC1 encoded private EC key */ static int pk_parse_key_sec1_der( ecp_keypair *eck, const unsigned char *key, size_t keylen ) { int ret; int version, pubkey_done; size_t len; 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 = asn1_get_tag( &p, end, &len, ASN1_CONSTRUCTED | ASN1_SEQUENCE ) ) != 0 ) { return( POLARSSL_ERR_PK_KEY_INVALID_FORMAT + ret ); } end = p + len; if( ( ret = asn1_get_int( &p, end, &version ) ) != 0 ) return( POLARSSL_ERR_PK_KEY_INVALID_FORMAT + ret ); if( version != 1 ) return( POLARSSL_ERR_PK_KEY_INVALID_VERSION ); if( ( ret = asn1_get_tag( &p, end, &len, ASN1_OCTET_STRING ) ) != 0 ) return( POLARSSL_ERR_PK_KEY_INVALID_FORMAT + ret ); if( ( ret = mpi_read_binary( &eck->d, p, len ) ) != 0 ) { ecp_keypair_free( eck ); return( POLARSSL_ERR_PK_KEY_INVALID_FORMAT + ret ); } p += len; pubkey_done = 0; if( p != end ) { /* * Is 'parameters' present? */ if( ( ret = asn1_get_tag( &p, end, &len, ASN1_CONTEXT_SPECIFIC | ASN1_CONSTRUCTED | 0 ) ) == 0 ) { if( ( ret = pk_get_ecparams( &p, p + len, ¶ms) ) != 0 || ( ret = pk_use_ecparams( ¶ms, &eck->grp ) ) != 0 ) { ecp_keypair_free( eck ); return( ret ); } } else if( ret != POLARSSL_ERR_ASN1_UNEXPECTED_TAG ) { ecp_keypair_free( eck ); return( POLARSSL_ERR_PK_KEY_INVALID_FORMAT + ret ); } /* * 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 = asn1_get_tag( &p, end, &len, ASN1_CONTEXT_SPECIFIC | ASN1_CONSTRUCTED | 1 ) ) == 0 ) { end2 = p + len; if( ( ret = asn1_get_bitstring_null( &p, end2, &len ) ) != 0 ) return( POLARSSL_ERR_PK_KEY_INVALID_FORMAT + ret ); if( p + len != end2 ) return( POLARSSL_ERR_PK_KEY_INVALID_FORMAT + POLARSSL_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 != POLARSSL_ERR_ECP_FEATURE_UNAVAILABLE ) return( POLARSSL_ERR_PK_KEY_INVALID_FORMAT ); } } else if( ret != POLARSSL_ERR_ASN1_UNEXPECTED_TAG ) { ecp_keypair_free( eck ); return( POLARSSL_ERR_PK_KEY_INVALID_FORMAT + ret ); } } if( ! pubkey_done && ( ret = ecp_mul( &eck->grp, &eck->Q, &eck->d, &eck->grp.G, NULL, NULL ) ) != 0 ) { ecp_keypair_free( eck ); return( POLARSSL_ERR_PK_KEY_INVALID_FORMAT + ret ); } if( ( ret = ecp_check_privkey( &eck->grp, &eck->d ) ) != 0 ) { ecp_keypair_free( eck ); return( ret ); } return( 0 ); } #endif /* POLARSSL_ECP_C */ /* * Parse an unencrypted PKCS#8 encoded private key */ static int pk_parse_key_pkcs8_unencrypted_der( pk_context *pk, const unsigned char* key, size_t keylen ) { int ret, version; size_t len; asn1_buf params; unsigned char *p = (unsigned char *) key; unsigned char *end = p + keylen; pk_type_t pk_alg = POLARSSL_PK_NONE; const pk_info_t *pk_info; /* * This function parses the PrivatKeyInfo 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 = asn1_get_tag( &p, end, &len, ASN1_CONSTRUCTED | ASN1_SEQUENCE ) ) != 0 ) { return( POLARSSL_ERR_PK_KEY_INVALID_FORMAT + ret ); } end = p + len; if( ( ret = asn1_get_int( &p, end, &version ) ) != 0 ) return( POLARSSL_ERR_PK_KEY_INVALID_FORMAT + ret ); if( version != 0 ) return( POLARSSL_ERR_PK_KEY_INVALID_VERSION + ret ); if( ( ret = pk_get_pk_alg( &p, end, &pk_alg, ¶ms ) ) != 0 ) return( POLARSSL_ERR_PK_KEY_INVALID_FORMAT + ret ); if( ( ret = asn1_get_tag( &p, end, &len, ASN1_OCTET_STRING ) ) != 0 ) return( POLARSSL_ERR_PK_KEY_INVALID_FORMAT + ret ); if( len < 1 ) return( POLARSSL_ERR_PK_KEY_INVALID_FORMAT + POLARSSL_ERR_ASN1_OUT_OF_DATA ); if( ( pk_info = pk_info_from_type( pk_alg ) ) == NULL ) return( POLARSSL_ERR_PK_UNKNOWN_PK_ALG ); if( ( ret = pk_init_ctx( pk, pk_info ) ) != 0 ) return( ret ); #if defined(POLARSSL_RSA_C) if( pk_alg == POLARSSL_PK_RSA ) { if( ( ret = pk_parse_key_pkcs1_der( pk_rsa( *pk ), p, len ) ) != 0 ) { pk_free( pk ); return( ret ); } } else #endif /* POLARSSL_RSA_C */ #if defined(POLARSSL_ECP_C) if( pk_alg == POLARSSL_PK_ECKEY || pk_alg == POLARSSL_PK_ECKEY_DH ) { if( ( ret = pk_use_ecparams( ¶ms, &pk_ec( *pk )->grp ) ) != 0 || ( ret = pk_parse_key_sec1_der( pk_ec( *pk ), p, len ) ) != 0 ) { pk_free( pk ); return( ret ); } } else #endif /* POLARSSL_ECP_C */ return( POLARSSL_ERR_PK_UNKNOWN_PK_ALG ); return( 0 ); } /* * Parse an encrypted PKCS#8 encoded private key */ #if defined(POLARSSL_PKCS12_C) || defined(POLARSSL_PKCS5_C) static int pk_parse_key_pkcs8_encrypted_der( 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; asn1_buf pbe_alg_oid, pbe_params; #if defined(POLARSSL_PKCS12_C) cipher_type_t cipher_alg; md_type_t md_alg; #endif p = key; end = p + keylen; if( pwdlen == 0 ) return( POLARSSL_ERR_PK_PASSWORD_REQUIRED ); /* * This function parses the EncryptedPrivatKeyInfo object (PKCS#8) * * EncryptedPrivateKeyInfo ::= SEQUENCE { * encryptionAlgorithm EncryptionAlgorithmIdentifier, * encryptedData EncryptedData * } * * EncryptionAlgorithmIdentifier ::= AlgorithmIdentifier * * EncryptedData ::= OCTET STRING * * The EncryptedData OCTET STRING is a PKCS#8 PrivateKeyInfo */ if( ( ret = asn1_get_tag( &p, end, &len, ASN1_CONSTRUCTED | ASN1_SEQUENCE ) ) != 0 ) { return( POLARSSL_ERR_PK_KEY_INVALID_FORMAT + ret ); } end = p + len; if( ( ret = asn1_get_alg( &p, end, &pbe_alg_oid, &pbe_params ) ) != 0 ) return( POLARSSL_ERR_PK_KEY_INVALID_FORMAT + ret ); if( ( ret = asn1_get_tag( &p, end, &len, ASN1_OCTET_STRING ) ) != 0 ) return( POLARSSL_ERR_PK_KEY_INVALID_FORMAT + ret ); buf = p; /* * Decrypt EncryptedData with appropriate PDE */ #if defined(POLARSSL_PKCS12_C) if( oid_get_pkcs12_pbe_alg( &pbe_alg_oid, &md_alg, &cipher_alg ) == 0 ) { if( ( ret = pkcs12_pbe( &pbe_params, PKCS12_PBE_DECRYPT, cipher_alg, md_alg, pwd, pwdlen, p, len, buf ) ) != 0 ) { if( ret == POLARSSL_ERR_PKCS12_PASSWORD_MISMATCH ) return( POLARSSL_ERR_PK_PASSWORD_MISMATCH ); return( ret ); } decrypted = 1; } else if( OID_CMP( OID_PKCS12_PBE_SHA1_RC4_128, &pbe_alg_oid ) ) { if( ( ret = pkcs12_pbe_sha1_rc4_128( &pbe_params, PKCS12_PBE_DECRYPT, pwd, pwdlen, p, len, buf ) ) != 0 ) { return( ret ); } // Best guess for password mismatch when using RC4. If first tag is // not ASN1_CONSTRUCTED | ASN1_SEQUENCE // if( *buf != ( ASN1_CONSTRUCTED | ASN1_SEQUENCE ) ) return( POLARSSL_ERR_PK_PASSWORD_MISMATCH ); decrypted = 1; } else #endif /* POLARSSL_PKCS12_C */ #if defined(POLARSSL_PKCS5_C) if( OID_CMP( OID_PKCS5_PBES2, &pbe_alg_oid ) ) { if( ( ret = pkcs5_pbes2( &pbe_params, PKCS5_DECRYPT, pwd, pwdlen, p, len, buf ) ) != 0 ) { if( ret == POLARSSL_ERR_PKCS5_PASSWORD_MISMATCH ) return( POLARSSL_ERR_PK_PASSWORD_MISMATCH ); return( ret ); } decrypted = 1; } else #endif /* POLARSSL_PKCS5_C */ { ((void) pwd); } if( decrypted == 0 ) return( POLARSSL_ERR_PK_FEATURE_UNAVAILABLE ); return( pk_parse_key_pkcs8_unencrypted_der( pk, buf, len ) ); } #endif /* POLARSSL_PKCS12_C || POLARSSL_PKCS5_C */ /* * Parse a private key */ int pk_parse_key( pk_context *pk, const unsigned char *key, size_t keylen, const unsigned char *pwd, size_t pwdlen ) { int ret; const pk_info_t *pk_info; #if defined(POLARSSL_PEM_PARSE_C) size_t len; pem_context pem; pem_init( &pem ); #if defined(POLARSSL_RSA_C) ret = pem_read_buffer( &pem, "-----BEGIN RSA PRIVATE KEY-----", "-----END RSA PRIVATE KEY-----", key, pwd, pwdlen, &len ); if( ret == 0 ) { pk_info = pk_info_from_type( POLARSSL_PK_RSA ); if( ( ret = pk_init_ctx( pk, pk_info ) ) != 0 || ( ret = pk_parse_key_pkcs1_der( pk_rsa( *pk ), pem.buf, pem.buflen ) ) != 0 ) { pk_free( pk ); } pem_free( &pem ); return( ret ); } else if( ret == POLARSSL_ERR_PEM_PASSWORD_MISMATCH ) return( POLARSSL_ERR_PK_PASSWORD_MISMATCH ); else if( ret == POLARSSL_ERR_PEM_PASSWORD_REQUIRED ) return( POLARSSL_ERR_PK_PASSWORD_REQUIRED ); else if( ret != POLARSSL_ERR_PEM_NO_HEADER_FOOTER_PRESENT ) return( ret ); #endif /* POLARSSL_RSA_C */ #if defined(POLARSSL_ECP_C) ret = pem_read_buffer( &pem, "-----BEGIN EC PRIVATE KEY-----", "-----END EC PRIVATE KEY-----", key, pwd, pwdlen, &len ); if( ret == 0 ) { pk_info = pk_info_from_type( POLARSSL_PK_ECKEY ); if( ( ret = pk_init_ctx( pk, pk_info ) ) != 0 || ( ret = pk_parse_key_sec1_der( pk_ec( *pk ), pem.buf, pem.buflen ) ) != 0 ) { pk_free( pk ); } pem_free( &pem ); return( ret ); } else if( ret == POLARSSL_ERR_PEM_PASSWORD_MISMATCH ) return( POLARSSL_ERR_PK_PASSWORD_MISMATCH ); else if( ret == POLARSSL_ERR_PEM_PASSWORD_REQUIRED ) return( POLARSSL_ERR_PK_PASSWORD_REQUIRED ); else if( ret != POLARSSL_ERR_PEM_NO_HEADER_FOOTER_PRESENT ) return( ret ); #endif /* POLARSSL_ECP_C */ ret = pem_read_buffer( &pem, "-----BEGIN PRIVATE KEY-----", "-----END PRIVATE KEY-----", key, NULL, 0, &len ); if( ret == 0 ) { if( ( ret = pk_parse_key_pkcs8_unencrypted_der( pk, pem.buf, pem.buflen ) ) != 0 ) { pk_free( pk ); } pem_free( &pem ); return( ret ); } else if( ret != POLARSSL_ERR_PEM_NO_HEADER_FOOTER_PRESENT ) return( ret ); #if defined(POLARSSL_PKCS12_C) || defined(POLARSSL_PKCS5_C) ret = pem_read_buffer( &pem, "-----BEGIN ENCRYPTED PRIVATE KEY-----", "-----END ENCRYPTED PRIVATE KEY-----", key, NULL, 0, &len ); if( ret == 0 ) { if( ( ret = pk_parse_key_pkcs8_encrypted_der( pk, pem.buf, pem.buflen, pwd, pwdlen ) ) != 0 ) { pk_free( pk ); } pem_free( &pem ); return( ret ); } else if( ret != POLARSSL_ERR_PEM_NO_HEADER_FOOTER_PRESENT ) return( ret ); #endif /* POLARSSL_PKCS12_C || POLARSSL_PKCS5_C */ #else ((void) pwd); ((void) pwdlen); #endif /* POLARSSL_PEM_PARSE_C */ /* * At this point we only know it's not a PEM formatted key. Could be any * of the known DER encoded private key formats * * We try the different DER format parsers to see if one passes without * error */ #if defined(POLARSSL_PKCS12_C) || defined(POLARSSL_PKCS5_C) { unsigned char *key_copy; if( ( key_copy = polarssl_malloc( keylen ) ) == NULL ) return( POLARSSL_ERR_PK_MALLOC_FAILED ); memcpy( key_copy, key, keylen ); ret = pk_parse_key_pkcs8_encrypted_der( pk, key_copy, keylen, pwd, pwdlen ); polarssl_zeroize( key_copy, keylen ); polarssl_free( key_copy ); } if( ret == 0 ) return( 0 ); pk_free( pk ); if( ret == POLARSSL_ERR_PK_PASSWORD_MISMATCH ) { return( ret ); } #endif /* POLARSSL_PKCS12_C || POLARSSL_PKCS5_C */ if( ( ret = pk_parse_key_pkcs8_unencrypted_der( pk, key, keylen ) ) == 0 ) return( 0 ); pk_free( pk ); #if defined(POLARSSL_RSA_C) pk_info = pk_info_from_type( POLARSSL_PK_RSA ); if( ( ret = pk_init_ctx( pk, pk_info ) ) != 0 || ( ret = pk_parse_key_pkcs1_der( pk_rsa( *pk ), key, keylen ) ) != 0 ) { pk_free( pk ); } else { return( 0 ); } #endif /* POLARSSL_RSA_C */ #if defined(POLARSSL_ECP_C) pk_info = pk_info_from_type( POLARSSL_PK_ECKEY ); if( ( ret = pk_init_ctx( pk, pk_info ) ) != 0 || ( ret = pk_parse_key_sec1_der( pk_ec( *pk ), key, keylen ) ) != 0 ) { pk_free( pk ); } else { return( 0 ); } #endif /* POLARSSL_ECP_C */ return( POLARSSL_ERR_PK_KEY_INVALID_FORMAT ); } /* * Parse a public key */ int pk_parse_public_key( pk_context *ctx, const unsigned char *key, size_t keylen ) { int ret; unsigned char *p; #if defined(POLARSSL_PEM_PARSE_C) size_t len; pem_context pem; pem_init( &pem ); ret = pem_read_buffer( &pem, "-----BEGIN PUBLIC KEY-----", "-----END PUBLIC KEY-----", key, NULL, 0, &len ); if( ret == 0 ) { /* * Was PEM encoded */ key = pem.buf; keylen = pem.buflen; } else if( ret != POLARSSL_ERR_PEM_NO_HEADER_FOOTER_PRESENT ) { pem_free( &pem ); return( ret ); } #endif /* POLARSSL_PEM_PARSE_C */ p = (unsigned char *) key; ret = pk_parse_subpubkey( &p, p + keylen, ctx ); #if defined(POLARSSL_PEM_PARSE_C) pem_free( &pem ); #endif return( ret ); } #endif /* POLARSSL_PK_PARSE_C */