Diff: mbedtls/source/pkwrite.c

Revision:

11:cada08fc8a70

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/mbedtls/source/pkwrite.c	Thu Jun 09 17:08:36 2016 +0000
@@ -0,0 +1,439 @@
+/*
+ *  Public Key layer for writing key files and structures
+ *
+ *  Copyright (C) 2006-2015, ARM Limited, All Rights Reserved
+ *  SPDX-License-Identifier: Apache-2.0
+ *
+ *  Licensed under the Apache License, Version 2.0 (the "License"); you may
+ *  not use this file except in compliance with the License.
+ *  You may obtain a copy of the License at
+ *
+ *  http://www.apache.org/licenses/LICENSE-2.0
+ *
+ *  Unless required by applicable law or agreed to in writing, software
+ *  distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ *  WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ *  See the License for the specific language governing permissions and
+ *  limitations under the License.
+ *
+ *  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_WRITE_C)
+
+#include "mbedtls/pk.h"
+#include "mbedtls/asn1write.h"
+#include "mbedtls/oid.h"
+
+#include <string.h>
+
+#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_WRITE_C)
+#include "mbedtls/pem.h"
+#endif
+
+#if defined(MBEDTLS_PLATFORM_C)
+#include "mbedtls/platform.h"
+#else
+#include <stdlib.h>
+#define mbedtls_calloc    calloc
+#define mbedtls_free       free
+#endif
+
+#if defined(MBEDTLS_RSA_C)
+/*
+ *  RSAPublicKey ::= SEQUENCE {
+ *      modulus           INTEGER,  -- n
+ *      publicExponent    INTEGER   -- e
+ *  }
+ */
+static int pk_write_rsa_pubkey( unsigned char **p, unsigned char *start,
+                                  mbedtls_rsa_context *rsa )
+{
+    int ret;
+    size_t len = 0;
+
+    MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_mpi( p, start, &rsa->E ) );
+    MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_mpi( p, start, &rsa->N ) );
+
+    MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_len( p, start, len ) );
+    MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_tag( p, start, MBEDTLS_ASN1_CONSTRUCTED |
+                                                 MBEDTLS_ASN1_SEQUENCE ) );
+
+    return( (int) len );
+}
+#endif /* MBEDTLS_RSA_C */
+
+#if defined(MBEDTLS_ECP_C)
+/*
+ * EC public key is an EC point
+ */
+static int pk_write_ec_pubkey( unsigned char **p, unsigned char *start,
+                                 mbedtls_ecp_keypair *ec )
+{
+    int ret;
+    size_t len = 0;
+    unsigned char buf[MBEDTLS_ECP_MAX_PT_LEN];
+
+    if( ( ret = mbedtls_ecp_point_write_binary( &ec->grp, &ec->Q,
+                                        MBEDTLS_ECP_PF_UNCOMPRESSED,
+                                        &len, buf, sizeof( buf ) ) ) != 0 )
+    {
+        return( ret );
+    }
+
+    if( *p < start || (size_t)( *p - start ) < len )
+        return( MBEDTLS_ERR_ASN1_BUF_TOO_SMALL );
+
+    *p -= len;
+    memcpy( *p, buf, len );
+
+    return( (int) len );
+}
+
+/*
+ * ECParameters ::= CHOICE {
+ *   namedCurve         OBJECT IDENTIFIER
+ * }
+ */
+static int pk_write_ec_param( unsigned char **p, unsigned char *start,
+                                mbedtls_ecp_keypair *ec )
+{
+    int ret;
+    size_t len = 0;
+    const char *oid;
+    size_t oid_len;
+
+    if( ( ret = mbedtls_oid_get_oid_by_ec_grp( ec->grp.id, &oid, &oid_len ) ) != 0 )
+        return( ret );
+
+    MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_oid( p, start, oid, oid_len ) );
+
+    return( (int) len );
+}
+#endif /* MBEDTLS_ECP_C */
+
+int mbedtls_pk_write_pubkey( unsigned char **p, unsigned char *start,
+                     const mbedtls_pk_context *key )
+{
+    int ret;
+    size_t len = 0;
+
+#if defined(MBEDTLS_RSA_C)
+    if( mbedtls_pk_get_type( key ) == MBEDTLS_PK_RSA )
+        MBEDTLS_ASN1_CHK_ADD( len, pk_write_rsa_pubkey( p, start, mbedtls_pk_rsa( *key ) ) );
+    else
+#endif
+#if defined(MBEDTLS_ECP_C)
+    if( mbedtls_pk_get_type( key ) == MBEDTLS_PK_ECKEY )
+        MBEDTLS_ASN1_CHK_ADD( len, pk_write_ec_pubkey( p, start, mbedtls_pk_ec( *key ) ) );
+    else
+#endif
+        return( MBEDTLS_ERR_PK_FEATURE_UNAVAILABLE );
+
+    return( (int) len );
+}
+
+int mbedtls_pk_write_pubkey_der( mbedtls_pk_context *key, unsigned char *buf, size_t size )
+{
+    int ret;
+    unsigned char *c;
+    size_t len = 0, par_len = 0, oid_len;
+    const char *oid;
+
+    c = buf + size;
+
+    MBEDTLS_ASN1_CHK_ADD( len, mbedtls_pk_write_pubkey( &c, buf, key ) );
+
+    if( c - buf < 1 )
+        return( MBEDTLS_ERR_ASN1_BUF_TOO_SMALL );
+
+    /*
+     *  SubjectPublicKeyInfo  ::=  SEQUENCE  {
+     *       algorithm            AlgorithmIdentifier,
+     *       subjectPublicKey     BIT STRING }
+     */
+    *--c = 0;
+    len += 1;
+
+    MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_len( &c, buf, len ) );
+    MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_tag( &c, buf, MBEDTLS_ASN1_BIT_STRING ) );
+
+    if( ( ret = mbedtls_oid_get_oid_by_pk_alg( mbedtls_pk_get_type( key ),
+                                       &oid, &oid_len ) ) != 0 )
+    {
+        return( ret );
+    }
+
+#if defined(MBEDTLS_ECP_C)
+    if( mbedtls_pk_get_type( key ) == MBEDTLS_PK_ECKEY )
+    {
+        MBEDTLS_ASN1_CHK_ADD( par_len, pk_write_ec_param( &c, buf, mbedtls_pk_ec( *key ) ) );
+    }
+#endif
+
+    MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_algorithm_identifier( &c, buf, oid, oid_len,
+                                                        par_len ) );
+
+    MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_len( &c, buf, len ) );
+    MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_tag( &c, buf, MBEDTLS_ASN1_CONSTRUCTED |
+                                                MBEDTLS_ASN1_SEQUENCE ) );
+
+    return( (int) len );
+}
+
+int mbedtls_pk_write_key_der( mbedtls_pk_context *key, unsigned char *buf, size_t size )
+{
+    int ret;
+    unsigned char *c = buf + size;
+    size_t len = 0;
+
+#if defined(MBEDTLS_RSA_C)
+    if( mbedtls_pk_get_type( key ) == MBEDTLS_PK_RSA )
+    {
+        mbedtls_rsa_context *rsa = mbedtls_pk_rsa( *key );
+
+        MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_mpi( &c, buf, &rsa->QP ) );
+        MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_mpi( &c, buf, &rsa->DQ ) );
+        MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_mpi( &c, buf, &rsa->DP ) );
+        MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_mpi( &c, buf, &rsa->Q ) );
+        MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_mpi( &c, buf, &rsa->P ) );
+        MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_mpi( &c, buf, &rsa->D ) );
+        MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_mpi( &c, buf, &rsa->E ) );
+        MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_mpi( &c, buf, &rsa->N ) );
+        MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_int( &c, buf, 0 ) );
+
+        MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_len( &c, buf, len ) );
+        MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_tag( &c, buf, MBEDTLS_ASN1_CONSTRUCTED |
+                                                    MBEDTLS_ASN1_SEQUENCE ) );
+    }
+    else
+#endif /* MBEDTLS_RSA_C */
+#if defined(MBEDTLS_ECP_C)
+    if( mbedtls_pk_get_type( key ) == MBEDTLS_PK_ECKEY )
+    {
+        mbedtls_ecp_keypair *ec = mbedtls_pk_ec( *key );
+        size_t pub_len = 0, par_len = 0;
+
+        /*
+         * 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
+         *    }
+         */
+
+        /* publicKey */
+        MBEDTLS_ASN1_CHK_ADD( pub_len, pk_write_ec_pubkey( &c, buf, ec ) );
+
+        if( c - buf < 1 )
+            return( MBEDTLS_ERR_ASN1_BUF_TOO_SMALL );
+        *--c = 0;
+        pub_len += 1;
+
+        MBEDTLS_ASN1_CHK_ADD( pub_len, mbedtls_asn1_write_len( &c, buf, pub_len ) );
+        MBEDTLS_ASN1_CHK_ADD( pub_len, mbedtls_asn1_write_tag( &c, buf, MBEDTLS_ASN1_BIT_STRING ) );
+
+        MBEDTLS_ASN1_CHK_ADD( pub_len, mbedtls_asn1_write_len( &c, buf, pub_len ) );
+        MBEDTLS_ASN1_CHK_ADD( pub_len, mbedtls_asn1_write_tag( &c, buf,
+                            MBEDTLS_ASN1_CONTEXT_SPECIFIC | MBEDTLS_ASN1_CONSTRUCTED | 1 ) );
+        len += pub_len;
+
+        /* parameters */
+        MBEDTLS_ASN1_CHK_ADD( par_len, pk_write_ec_param( &c, buf, ec ) );
+
+        MBEDTLS_ASN1_CHK_ADD( par_len, mbedtls_asn1_write_len( &c, buf, par_len ) );
+        MBEDTLS_ASN1_CHK_ADD( par_len, mbedtls_asn1_write_tag( &c, buf,
+                            MBEDTLS_ASN1_CONTEXT_SPECIFIC | MBEDTLS_ASN1_CONSTRUCTED | 0 ) );
+        len += par_len;
+
+        /* privateKey: write as MPI then fix tag */
+        MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_mpi( &c, buf, &ec->d ) );
+        *c = MBEDTLS_ASN1_OCTET_STRING;
+
+        /* version */
+        MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_int( &c, buf, 1 ) );
+
+        MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_len( &c, buf, len ) );
+        MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_tag( &c, buf, MBEDTLS_ASN1_CONSTRUCTED |
+                                                    MBEDTLS_ASN1_SEQUENCE ) );
+    }
+    else
+#endif /* MBEDTLS_ECP_C */
+        return( MBEDTLS_ERR_PK_FEATURE_UNAVAILABLE );
+
+    return( (int) len );
+}
+
+#if defined(MBEDTLS_PEM_WRITE_C)
+
+#define PEM_BEGIN_PUBLIC_KEY    "-----BEGIN PUBLIC KEY-----\n"
+#define PEM_END_PUBLIC_KEY      "-----END PUBLIC KEY-----\n"
+
+#define PEM_BEGIN_PRIVATE_KEY_RSA   "-----BEGIN RSA PRIVATE KEY-----\n"
+#define PEM_END_PRIVATE_KEY_RSA     "-----END RSA PRIVATE KEY-----\n"
+#define PEM_BEGIN_PRIVATE_KEY_EC    "-----BEGIN EC PRIVATE KEY-----\n"
+#define PEM_END_PRIVATE_KEY_EC      "-----END EC PRIVATE KEY-----\n"
+
+/*
+ * Max sizes of key per types. Shown as tag + len (+ content).
+ */
+
+#if defined(MBEDTLS_RSA_C)
+/*
+ * RSA public keys:
+ *  SubjectPublicKeyInfo  ::=  SEQUENCE  {          1 + 3
+ *       algorithm            AlgorithmIdentifier,  1 + 1 (sequence)
+ *                                                + 1 + 1 + 9 (rsa oid)
+ *                                                + 1 + 1 (params null)
+ *       subjectPublicKey     BIT STRING }          1 + 3 + (1 + below)
+ *  RSAPublicKey ::= SEQUENCE {                     1 + 3
+ *      modulus           INTEGER,  -- n            1 + 3 + MPI_MAX + 1
+ *      publicExponent    INTEGER   -- e            1 + 3 + MPI_MAX + 1
+ *  }
+ */
+#define RSA_PUB_DER_MAX_BYTES   38 + 2 * MBEDTLS_MPI_MAX_SIZE
+
+/*
+ * RSA private keys:
+ *  RSAPrivateKey ::= SEQUENCE {                    1 + 3
+ *      version           Version,                  1 + 1 + 1
+ *      modulus           INTEGER,                  1 + 3 + MPI_MAX + 1
+ *      publicExponent    INTEGER,                  1 + 3 + MPI_MAX + 1
+ *      privateExponent   INTEGER,                  1 + 3 + MPI_MAX + 1
+ *      prime1            INTEGER,                  1 + 3 + MPI_MAX / 2 + 1
+ *      prime2            INTEGER,                  1 + 3 + MPI_MAX / 2 + 1
+ *      exponent1         INTEGER,                  1 + 3 + MPI_MAX / 2 + 1
+ *      exponent2         INTEGER,                  1 + 3 + MPI_MAX / 2 + 1
+ *      coefficient       INTEGER,                  1 + 3 + MPI_MAX / 2 + 1
+ *      otherPrimeInfos   OtherPrimeInfos OPTIONAL  0 (not supported)
+ *  }
+ */
+#define MPI_MAX_SIZE_2          MBEDTLS_MPI_MAX_SIZE / 2 + \
+                                MBEDTLS_MPI_MAX_SIZE % 2
+#define RSA_PRV_DER_MAX_BYTES   47 + 3 * MBEDTLS_MPI_MAX_SIZE \
+                                   + 5 * MPI_MAX_SIZE_2
+
+#else /* MBEDTLS_RSA_C */
+
+#define RSA_PUB_DER_MAX_BYTES   0
+#define RSA_PRV_DER_MAX_BYTES   0
+
+#endif /* MBEDTLS_RSA_C */
+
+#if defined(MBEDTLS_ECP_C)
+/*
+ * EC public keys:
+ *  SubjectPublicKeyInfo  ::=  SEQUENCE  {      1 + 2
+ *    algorithm         AlgorithmIdentifier,    1 + 1 (sequence)
+ *                                            + 1 + 1 + 7 (ec oid)
+ *                                            + 1 + 1 + 9 (namedCurve oid)
+ *    subjectPublicKey  BIT STRING              1 + 2 + 1               [1]
+ *                                            + 1 (point format)        [1]
+ *                                            + 2 * ECP_MAX (coords)    [1]
+ *  }
+ */
+#define ECP_PUB_DER_MAX_BYTES   30 + 2 * MBEDTLS_ECP_MAX_BYTES
+
+/*
+ * EC private keys:
+ * ECPrivateKey ::= SEQUENCE {                  1 + 2
+ *      version        INTEGER ,                1 + 1 + 1
+ *      privateKey     OCTET STRING,            1 + 1 + ECP_MAX
+ *      parameters [0] ECParameters OPTIONAL,   1 + 1 + (1 + 1 + 9)
+ *      publicKey  [1] BIT STRING OPTIONAL      1 + 2 + [1] above
+ *    }
+ */
+#define ECP_PRV_DER_MAX_BYTES   29 + 3 * MBEDTLS_ECP_MAX_BYTES
+
+#else /* MBEDTLS_ECP_C */
+
+#define ECP_PUB_DER_MAX_BYTES   0
+#define ECP_PRV_DER_MAX_BYTES   0
+
+#endif /* MBEDTLS_ECP_C */
+
+#define PUB_DER_MAX_BYTES   RSA_PUB_DER_MAX_BYTES > ECP_PUB_DER_MAX_BYTES ? \
+                            RSA_PUB_DER_MAX_BYTES : ECP_PUB_DER_MAX_BYTES
+#define PRV_DER_MAX_BYTES   RSA_PRV_DER_MAX_BYTES > ECP_PRV_DER_MAX_BYTES ? \
+                            RSA_PRV_DER_MAX_BYTES : ECP_PRV_DER_MAX_BYTES
+
+int mbedtls_pk_write_pubkey_pem( mbedtls_pk_context *key, unsigned char *buf, size_t size )
+{
+    int ret;
+    unsigned char output_buf[PUB_DER_MAX_BYTES];
+    size_t olen = 0;
+
+    if( ( ret = mbedtls_pk_write_pubkey_der( key, output_buf,
+                                     sizeof(output_buf) ) ) < 0 )
+    {
+        return( ret );
+    }
+
+    if( ( ret = mbedtls_pem_write_buffer( PEM_BEGIN_PUBLIC_KEY, PEM_END_PUBLIC_KEY,
+                                  output_buf + sizeof(output_buf) - ret,
+                                  ret, buf, size, &olen ) ) != 0 )
+    {
+        return( ret );
+    }
+
+    return( 0 );
+}
+
+int mbedtls_pk_write_key_pem( mbedtls_pk_context *key, unsigned char *buf, size_t size )
+{
+    int ret;
+    unsigned char output_buf[PRV_DER_MAX_BYTES];
+    const char *begin, *end;
+    size_t olen = 0;
+
+    if( ( ret = mbedtls_pk_write_key_der( key, output_buf, sizeof(output_buf) ) ) < 0 )
+        return( ret );
+
+#if defined(MBEDTLS_RSA_C)
+    if( mbedtls_pk_get_type( key ) == MBEDTLS_PK_RSA )
+    {
+        begin = PEM_BEGIN_PRIVATE_KEY_RSA;
+        end = PEM_END_PRIVATE_KEY_RSA;
+    }
+    else
+#endif
+#if defined(MBEDTLS_ECP_C)
+    if( mbedtls_pk_get_type( key ) == MBEDTLS_PK_ECKEY )
+    {
+        begin = PEM_BEGIN_PRIVATE_KEY_EC;
+        end = PEM_END_PRIVATE_KEY_EC;
+    }
+    else
+#endif
+        return( MBEDTLS_ERR_PK_FEATURE_UNAVAILABLE );
+
+    if( ( ret = mbedtls_pem_write_buffer( begin, end,
+                                  output_buf + sizeof(output_buf) - ret,
+                                  ret, buf, size, &olen ) ) != 0 )
+    {
+        return( ret );
+    }
+
+    return( 0 );
+}
+#endif /* MBEDTLS_PEM_WRITE_C */
+
+#endif /* MBEDTLS_PK_WRITE_C */