/*

  Copyright (c) 2011 Samuel Lidén Borell <samuel@kodafritt.se>
 
  Permission is hereby granted, free of charge, to any person obtaining a copy
  of this software and associated documentation files (the "Software"), to deal
  in the Software without restriction, including without limitation the rights
  to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
  copies of the Software, and to permit persons to whom the Software is
  furnished to do so, subject to the following conditions:
  
  The above copyright notice and this permission notice shall be included in
  all copies or substantial portions of the Software.
  
  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
  AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
  OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
  THE SOFTWARE.

*/

#include "request.h"

#include <stdbool.h>
#include <stdlib.h>
#include <openssl/asn1t.h>

// Hack to mark things as context specific
static int context_specific_i2d(ASN1_VALUE **val, unsigned char **out,
                                const ASN1_ITEM *it) {
    unsigned char *binary = NULL;
    int length = ASN1_item_i2d(*val, (out ? &binary : NULL), it);
    
    if (out) {
        // Make context specific
        binary[0] = V_ASN1_CONTEXT_SPECIFIC |
                    V_ASN1_CONSTRUCTED;
        
        // Copy result to output buffer
        if (!binary) return -1;
        
        memcpy(*out, binary, length);
        *out += length;
    }
        
    return length;
}

#if OPENSSL_VERSION_NUMBER >= 0x01000000
// OpenSSL 1.0.0
#define IMPLEMENT_CONT_SPEC_HACK(name) \
    static int name##_ex_i2d(ASN1_VALUE **val, unsigned char **out, \
                                  const ASN1_ITEM *it, int tag, int aclass) { \
        return context_specific_i2d(val, out, ASN1_ITEM_rptr(name)); \
    } \
    \
    const ASN1_EXTERN_FUNCS name##_ff = { \
        NULL, NULL, NULL, NULL, NULL, name##_ex_i2d, NULL \
    }; \
    \
    IMPLEMENT_EXTERN_ASN1(name##_cont, V_ASN1_SEQUENCE, name##_ff)

#else
// OpenSSL 0.9.8
#define IMPLEMENT_CONT_SPEC_HACK(name) \
    static int name##_ex_i2d(ASN1_VALUE **val, unsigned char **out, \
                                  const ASN1_ITEM *it, int tag, int aclass) { \
        return context_specific_i2d(val, out, ASN1_ITEM_rptr(name)); \
    } \
    \
    const ASN1_EXTERN_FUNCS name##_ff = { \
        NULL, NULL, NULL, NULL, NULL, name##_ex_i2d, \
    }; \
    \
    IMPLEMENT_EXTERN_ASN1(name##_cont, V_ASN1_SEQUENCE, name##_ff)
#endif

// Request body part
typedef struct {
    ASN1_INTEGER *bodyPartID;
    X509_REQ *csr;
} REQ_BODY_PART;

ASN1_SEQUENCE(REQ_BODY_PART) = {
    ASN1_SIMPLE(REQ_BODY_PART, bodyPartID, ASN1_INTEGER),
    ASN1_SIMPLE(REQ_BODY_PART, csr, X509_REQ)
} ASN1_SEQUENCE_END(REQ_BODY_PART)

IMPLEMENT_ASN1_FUNCTIONS(REQ_BODY_PART)
IMPLEMENT_CONT_SPEC_HACK(REQ_BODY_PART)

// OtherMsg body part
typedef struct {
    ASN1_INTEGER *bodyPartID;
    ASN1_OBJECT *otherMsgType;
    ASN1_IA5STRING *otherMsgValue;
} OTHERMSG_BODY_PART;

ASN1_SEQUENCE(OTHERMSG_BODY_PART) = {
    ASN1_SIMPLE(OTHERMSG_BODY_PART, bodyPartID, ASN1_INTEGER),
    ASN1_SIMPLE(OTHERMSG_BODY_PART, otherMsgType, ASN1_OBJECT),
    ASN1_SIMPLE(OTHERMSG_BODY_PART, otherMsgValue, ASN1_IA5STRING)
} ASN1_SEQUENCE_END(OTHERMSG_BODY_PART)

IMPLEMENT_ASN1_FUNCTIONS(OTHERMSG_BODY_PART)
IMPLEMENT_CONT_SPEC_HACK(OTHERMSG_BODY_PART)

// PKIData
typedef struct {
    STACK *controlSequence;
    STACK *reqSequence;
    STACK *cmsSequence;
    STACK *otherMsgSequence;
} PKIDATA;

ASN1_SEQUENCE(PKIDATA) = {
    ASN1_SEQUENCE_OF(PKIDATA, controlSequence, ASN1_NULL),
    ASN1_SEQUENCE_OF(PKIDATA, reqSequence, REQ_BODY_PART_cont),
    ASN1_SEQUENCE_OF(PKIDATA, cmsSequence, ASN1_NULL),
    ASN1_SEQUENCE_OF(PKIDATA, otherMsgSequence, OTHERMSG_BODY_PART),
} ASN1_SEQUENCE_END(PKIDATA)

IMPLEMENT_ASN1_FUNCTIONS(PKIDATA)


static ASN1_INTEGER *intToAsn1(int i) {
    ASN1_INTEGER *a = ASN1_INTEGER_new();
    if (!a) abort();
    ASN1_INTEGER_set(a, i);
    return a;
}

static ASN1_IA5STRING *strToIA5(const char *s) {
    ASN1_IA5STRING *a = ASN1_IA5STRING_new();
    if (!a) abort();
    ASN1_STRING_set((ASN1_STRING*)a, s, strlen(s));
    return a;
}

static REQ_BODY_PART *wrapBodyPartReq(X509_REQ *req, int bodyPartId) {
    REQ_BODY_PART *part = REQ_BODY_PART_new();
    if (part) {
        part->bodyPartID = intToAsn1(bodyPartId);
        part->csr = req;
    }
    return part;
}

static OTHERMSG_BODY_PART *makeOtherMsg(const char *oneTimePassword,
                                        int bodyPartId) {
    OTHERMSG_BODY_PART *part = OTHERMSG_BODY_PART_new();
    if (part) {
        part->bodyPartID = intToAsn1(bodyPartId);
        // 1.2.752.36 is iD2 Technologies AB
        part->otherMsgType = OBJ_txt2obj("1.2.752.36.4.1.1", 1);
        part->otherMsgValue = strToIA5(oneTimePassword);
        if (!part->otherMsgType) abort();
    }
    return part;
}

/**
 * Encapsulates a number of PKCS10 requests in a DER-encoded
 * PKCS7/CMC container.
 *
 * @param reqs        A STACK of X509_REQ. It's free'd by this function.
 * @param der         DER-encoded result
 * @param derLength   Length of DER in bytes
 */
void request_wrap(STACK *reqs, char **der, size_t *derLength) {
    PKIDATA *pkidata = PKIDATA_new();
    ASN1_TYPE *pkitype = NULL;
    PKCS7 *pkiP7 = NULL;
    PKCS7 *signdata = NULL;
    
    *der = NULL;
    if (!pkidata) goto end;
    
    // Add PKCS10 requests
    STACK *reqParts = pkidata->reqSequence;
    int num = sk_num(reqs);
    for (int i = 0; i < num; i++) {
        X509_REQ *req = (X509_REQ*)sk_value(reqs, i);
        if (!req) goto end;
        
        REQ_BODY_PART *reqPart = wrapBodyPartReq(req, 0x01000002+i);
        
        if (!reqPart ||
            !sk_push(reqParts, (char*)reqPart)) goto end;
    }
    
    // Add "CMC request"
    // TODO use the value from the OneTimePassword parameter
    OTHERMSG_BODY_PART *otherMsgPart = makeOtherMsg("Not Applicable", 0x01000001);
    
    if (!otherMsgPart ||
        !sk_push(pkidata->otherMsgSequence, (char*)otherMsgPart)) goto end;
    
    // Wrap in CMC PKIData structure
    pkitype = ASN1_TYPE_new();
    if (!pkitype) goto end;
    pkitype->type = V_ASN1_SEQUENCE;
    if (!ASN1_pack_string(pkidata, (i2d_of_void*)i2d_PKIDATA,
                            &pkitype->value.sequence)) goto end;
    
    PKIDATA_free(pkidata);
    pkidata = NULL;
    
    pkiP7 = PKCS7_new();
    if (!pkiP7 ||
        !PKCS7_set0_type_other(pkiP7, NID_id_cct_PKIData, pkitype)) goto end;
    
    // Wrap in PKCS7 SignedData structure
    signdata = PKCS7_new();
    if (!signdata ||
        !PKCS7_set_type(signdata, NID_pkcs7_signed) ||
        !PKCS7_set_content(signdata, pkiP7)) goto end;
    
    // Encode data
    *derLength = i2d_PKCS7(signdata, (unsigned char**)der);
    
  end:
    if (signdata) PKCS7_free(signdata);
    else if (pkiP7) PKCS7_free(pkiP7);
    else if (pkitype) ASN1_TYPE_free(pkitype);
    PKIDATA_free(pkidata);
}