/* This Source Code Form is subject to the terms of the Mozilla Public

 * License, v. 2.0. If a copy of the MPL was not distributed with this

 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

/*

 * CMS encryptedData methods.

 */

#include "cmslocal.h"

#include "keyhi.h"

#include "secasn1.h"

#include "secitem.h"

#include "secoid.h"

#include "pk11func.h"

#include "prtime.h"

#include "secerr.h"

#include "secpkcs5.h"

#include "smime.h"

/*

 * NSS_CMSEncryptedData_Create - create an empty encryptedData object.

 *

 * "algorithm" specifies the bulk encryption algorithm to use.

 * "keysize" is the key size.

 *

 * An error results in a return value of NULL and an error set.

 * (Retrieve specific errors via PORT_GetError()/XP_GetError().)

 */

NSSCMSEncryptedData *

NSS_CMSEncryptedData_Create(NSSCMSMessage *cmsg, SECOidTag algorithm,

                            int keysize)

{

    void *mark;

    NSSCMSEncryptedData *encd;

    PLArenaPool *poolp;

    SECAlgorithmID *pbe_algid;

    SECStatus rv;

    poolp = cmsg->poolp;

    mark = PORT_ArenaMark(poolp);

    encd = PORT_ArenaZNew(poolp, NSSCMSEncryptedData);

    if (encd == NULL)

        goto loser;

    encd->cmsg = cmsg;

    /* version is set in NSS_CMSEncryptedData_Encode_BeforeStart() */

    if (!SEC_PKCS5IsAlgorithmPBEAlgTag(algorithm)) {

        rv = NSS_CMSContentInfo_SetContentEncAlg(poolp, &(encd->contentInfo),

                                                 algorithm, NULL, keysize);

    } else {

        /* Assume password-based-encryption.

         * Note: we can't generate pkcs5v2 from this interface.

         * PK11_CreateBPEAlgorithmID generates pkcs5v2 by accepting

         * non-PBE oids and assuming that they are pkcs5v2 oids, but

         * NSS_CMSEncryptedData_Create accepts non-PBE oids as regular

         * CMS encrypted data, so we can't tell NSS_CMS_EncryptedData_Create

         * to create pkcs5v2 PBEs */

        pbe_algid = PK11_CreatePBEAlgorithmID(algorithm, 1, NULL);

        if (pbe_algid == NULL) {

            rv = SECFailure;

        } else {

            rv = NSS_CMSContentInfo_SetContentEncAlgID(poolp,

                                                       &(encd->contentInfo),

                                                       pbe_algid, keysize);

            SECOID_DestroyAlgorithmID(pbe_algid, PR_TRUE);

        }

    }

    if (rv != SECSuccess)

        goto loser;

    PORT_ArenaUnmark(poolp, mark);

    return encd;

loser:

    PORT_ArenaRelease(poolp, mark);

    return NULL;

}

/*

 * NSS_CMSEncryptedData_Destroy - destroy an encryptedData object

 */

void

NSS_CMSEncryptedData_Destroy(NSSCMSEncryptedData *encd)

{

    /* everything's in a pool, so don't worry about the storage */

    if (encd != NULL) {

        NSS_CMSContentInfo_Destroy(&(encd->contentInfo));

    }

    return;

}

/*

 * NSS_CMSEncryptedData_GetContentInfo - return pointer to encryptedData object's contentInfo

 */

NSSCMSContentInfo *

NSS_CMSEncryptedData_GetContentInfo(NSSCMSEncryptedData *encd)

{

    return &(encd->contentInfo);

}

/*

 * NSS_CMSEncryptedData_Encode_BeforeStart - do all the necessary things to a EncryptedData

 *     before encoding begins.

 *

 * In particular:

 *  - set the correct version value.

 *  - get the encryption key

 */

SECStatus

NSS_CMSEncryptedData_Encode_BeforeStart(NSSCMSEncryptedData *encd)

{

    int version;

    PK11SymKey *bulkkey = NULL;

    SECItem *dummy;

    NSSCMSContentInfo *cinfo = &(encd->contentInfo);

    SECAlgorithmID *algid = NULL;

    if (NSS_CMSArray_IsEmpty((void **)encd->unprotectedAttr))

        version = NSS_CMS_ENCRYPTED_DATA_VERSION;

    else

        version = NSS_CMS_ENCRYPTED_DATA_VERSION_UPATTR;

    dummy = SEC_ASN1EncodeInteger(encd->cmsg->poolp, &(encd->version), version);

    if (dummy == NULL)

        return SECFailure;

    /* now get content encryption key (bulk key) by using our cmsg callback */

    if (encd->cmsg->decrypt_key_cb) {

        algid = NSS_CMSContentInfo_GetContentEncAlg(cinfo);

        bulkkey = (*encd->cmsg->decrypt_key_cb)(encd->cmsg->decrypt_key_cb_arg, algid);

    }

    if ((bulkkey == NULL) || (algid == NULL))

        return SECFailure;

    /* store the bulk key in the contentInfo so that the encoder can find it */

    NSS_CMSContentInfo_SetBulkKey(cinfo, bulkkey);

    PK11_FreeSymKey(bulkkey);

    return SECSuccess;

}

/*

 * NSS_CMSEncryptedData_Encode_BeforeData - set up encryption

 */

SECStatus

NSS_CMSEncryptedData_Encode_BeforeData(NSSCMSEncryptedData *encd)

{

    NSSCMSContentInfo *cinfo;

    PK11SymKey *bulkkey = NULL;

    SECAlgorithmID *algid;

    SECStatus rv = SECFailure;

    cinfo = &(encd->contentInfo);

    /* find bulkkey and algorithm - must have been set by NSS_CMSEncryptedData_Encode_BeforeStart */

    bulkkey = NSS_CMSContentInfo_GetBulkKey(cinfo);

    if (bulkkey == NULL) {

        goto loser;

    }

    algid = NSS_CMSContentInfo_GetContentEncAlg(cinfo);

    if (algid == NULL) {

        goto loser;

    }

    rv = NSS_CMSContentInfo_Private_Init(cinfo);

    if (rv != SECSuccess) {

        goto loser;

    }

    if (!NSS_SMIMEUtil_EncryptionAllowed(algid, bulkkey)) {

        goto loser;

    }

    /* this may modify algid (with IVs generated in a token).

     * it is therefore essential that algid is a pointer to the "real" contentEncAlg,

     * not just to a copy */

    cinfo->privateInfo->ciphcx = NSS_CMSCipherContext_StartEncrypt(encd->cmsg->poolp,

                                                                   bulkkey, algid);

    if (cinfo->privateInfo->ciphcx == NULL)

        goto loser;

    rv = SECSuccess;

loser:

    if (bulkkey) {

        PK11_FreeSymKey(bulkkey);

    }

    return rv;

}

/*

 * NSS_CMSEncryptedData_Encode_AfterData - finalize this encryptedData for encoding

 */

SECStatus

NSS_CMSEncryptedData_Encode_AfterData(NSSCMSEncryptedData *encd)

{

    if (encd->contentInfo.privateInfo && encd->contentInfo.privateInfo->ciphcx) {

        NSS_CMSCipherContext_Destroy(encd->contentInfo.privateInfo->ciphcx);

        encd->contentInfo.privateInfo->ciphcx = NULL;

    }

    /* nothing to do after data */

    return SECSuccess;

}

/*

 * NSS_CMSEncryptedData_Decode_BeforeData - find bulk key & set up decryption

 */

SECStatus

NSS_CMSEncryptedData_Decode_BeforeData(NSSCMSEncryptedData *encd)

{

    PK11SymKey *bulkkey = NULL;

    NSSCMSContentInfo *cinfo;

    SECAlgorithmID *bulkalg;

    SECStatus rv = SECFailure;

    cinfo = &(encd->contentInfo);

    bulkalg = NSS_CMSContentInfo_GetContentEncAlg(cinfo);

    if (encd->cmsg->decrypt_key_cb == NULL) /* no callback? no key../ */

        goto loser;

    bulkkey = (*encd->cmsg->decrypt_key_cb)(encd->cmsg->decrypt_key_cb_arg, bulkalg);

    if (bulkkey == NULL)

        /* no success finding a bulk key */

        goto loser;

    NSS_CMSContentInfo_SetBulkKey(cinfo, bulkkey);

    rv = NSS_CMSContentInfo_Private_Init(cinfo);

    if (rv != SECSuccess) {

        goto loser;

    }

    rv = SECFailure;

    if (!NSS_SMIMEUtil_DecryptionAllowed(bulkalg, bulkkey)) {

        goto loser;

    }

    cinfo->privateInfo->ciphcx = NSS_CMSCipherContext_StartDecrypt(bulkkey, bulkalg);

    if (cinfo->privateInfo->ciphcx == NULL)

        goto loser; /* error has been set by NSS_CMSCipherContext_StartDecrypt */

    rv = SECSuccess;

loser:

    if (bulkkey) {

        PK11_FreeSymKey(bulkkey);

    }

    return rv;

}

/*

 * NSS_CMSEncryptedData_Decode_AfterData - finish decrypting this encryptedData's content

 */

SECStatus

NSS_CMSEncryptedData_Decode_AfterData(NSSCMSEncryptedData *encd)

{

    if (encd->contentInfo.privateInfo && encd->contentInfo.privateInfo->ciphcx) {

        NSS_CMSCipherContext_Destroy(encd->contentInfo.privateInfo->ciphcx);

        encd->contentInfo.privateInfo->ciphcx = NULL;

    }

    return SECSuccess;

}

/*

 * NSS_CMSEncryptedData_Decode_AfterEnd - finish decoding this encryptedData

 */

SECStatus

NSS_CMSEncryptedData_Decode_AfterEnd(NSSCMSEncryptedData *encd)

{

    /* apply final touches */

    return SECSuccess;

}