/* 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 decoding.

 */

#include "cmslocal.h"

#include "cert.h"

#include "keyhi.h"

#include "secasn1.h"

#include "secitem.h"

#include "secoid.h"

#include "prtime.h"

#include "secerr.h"

struct NSSCMSDecoderContextStr {

    SEC_ASN1DecoderContext *dcx;      /* ASN.1 decoder context */

    NSSCMSMessage *cmsg;              /* backpointer to the root message */

    SECOidTag type;                   /* type of message */

    NSSCMSContent content;            /* pointer to message */

    NSSCMSDecoderContext *childp7dcx; /* inner CMS decoder context */

    PRBool saw_contents;

    int error;

    NSSCMSContentCallback cb;

    void *cb_arg;

    PRBool first_decoded;

    PRBool need_indefinite_finish;

};

struct NSSCMSDecoderDataStr {

    SECItem data; /* must be first */

    unsigned int totalBufferSize;

};

typedef struct NSSCMSDecoderDataStr NSSCMSDecoderData;

static void nss_cms_decoder_update_filter(void *arg, const char *data,

                                          unsigned long len, int depth,

                                          SEC_ASN1EncodingPart data_kind);

static SECStatus nss_cms_before_data(NSSCMSDecoderContext *p7dcx);

static SECStatus nss_cms_after_data(NSSCMSDecoderContext *p7dcx);

static SECStatus nss_cms_after_end(NSSCMSDecoderContext *p7dcx);

static void nss_cms_decoder_work_data(NSSCMSDecoderContext *p7dcx,

                                      const unsigned char *data,

                                      unsigned long len,

                                      PRBool final);

static NSSCMSDecoderData *nss_cms_create_decoder_data(PLArenaPool *poolp);

extern const SEC_ASN1Template NSSCMSMessageTemplate[];

static NSSCMSDecoderData *

nss_cms_create_decoder_data(PLArenaPool *poolp)

{

    NSSCMSDecoderData *decoderData = NULL;

    decoderData = (NSSCMSDecoderData *)

        PORT_ArenaAlloc(poolp, sizeof(NSSCMSDecoderData));

    if (!decoderData) {

        return NULL;

    }

    decoderData->data.data = NULL;

    decoderData->data.len = 0;

    decoderData->totalBufferSize = 0;

    return decoderData;

}

/*

 * nss_cms_decoder_notify -

 *  this is the driver of the decoding process. It gets called by the ASN.1

 *  decoder before and after an object is decoded.

 *  at various points in the decoding process, we intercept to set up and do

 *  further processing.

 */

static void

nss_cms_decoder_notify(void *arg, PRBool before, void *dest, int depth)

{

    NSSCMSDecoderContext *p7dcx;

    NSSCMSContentInfo *rootcinfo, *cinfo;

    PRBool after = !before;

    p7dcx = (NSSCMSDecoderContext *)arg;

    rootcinfo = &(p7dcx->cmsg->contentInfo);

/* XXX error handling: need to set p7dcx->error */

#ifdef CMSDEBUG

    fprintf(stderr, "%6.6s, dest = 0x%08x, depth = %d\n", before ? "before" : "after",

            dest, depth);

#endif

    /* so what are we working on right now? */

    if (p7dcx->type == SEC_OID_UNKNOWN) {

        /*

         * right now, we are still decoding the OUTER (root) cinfo

         * As soon as we know the inner content type, set up the info,

         * but NO inner decoder or filter. The root decoder handles the first

         * level children by itself - only for encapsulated contents (which

         * are encoded as DER inside of an OCTET STRING) we need to set up a

         * child decoder...

         */

        if (after && dest == &(rootcinfo->contentType)) {

            p7dcx->type = NSS_CMSContentInfo_GetContentTypeTag(rootcinfo);

            p7dcx->content = rootcinfo->content;

            /* is this ready already ? need to alloc? */

            /* XXX yes we need to alloc -- continue here */

        }

    } else if (NSS_CMSType_IsData(p7dcx->type)) {

        /* this can only happen if the outermost cinfo has DATA in it */

        /* otherwise, we handle this type implicitely in the inner decoders */

        if (before && dest == &(rootcinfo->content)) {

            /* cause the filter to put the data in the right place...

            ** We want the ASN.1 decoder to deliver the decoded bytes to us

            ** from now on

            */

            SEC_ASN1DecoderSetFilterProc(p7dcx->dcx,

                                         nss_cms_decoder_update_filter,

                                         p7dcx,

                                         (PRBool)(p7dcx->cb != NULL));

        } else if (after && dest == &(rootcinfo->content.data)) {

            /* remove the filter */

            SEC_ASN1DecoderClearFilterProc(p7dcx->dcx);

        }

    } else if (NSS_CMSType_IsWrapper(p7dcx->type)) {

        if (!before || dest != &(rootcinfo->content)) {

            if (p7dcx->content.pointer == NULL)

                p7dcx->content = rootcinfo->content;

            /* get this data type's inner contentInfo */

            cinfo = NSS_CMSContent_GetContentInfo(p7dcx->content.pointer,

                                                  p7dcx->type);

            if (before && dest == &(cinfo->contentType)) {

                /* at this point, set up the &%$&$ back pointer */

                /* we cannot do it later, because the content itself

                 * is optional! */

                switch (p7dcx->type) {

                    case SEC_OID_PKCS7_SIGNED_DATA:

                        p7dcx->content.signedData->cmsg = p7dcx->cmsg;

                        break;

                    case SEC_OID_PKCS7_DIGESTED_DATA:

                        p7dcx->content.digestedData->cmsg = p7dcx->cmsg;

                        break;

                    case SEC_OID_PKCS7_ENVELOPED_DATA:

                        p7dcx->content.envelopedData->cmsg = p7dcx->cmsg;

                        break;

                    case SEC_OID_PKCS7_ENCRYPTED_DATA:

                        p7dcx->content.encryptedData->cmsg = p7dcx->cmsg;

                        break;

                    default:

                        p7dcx->content.genericData->cmsg = p7dcx->cmsg;

                        break;

                }

            }

            if (before && dest == &(cinfo->rawContent)) {

                /* we want the ASN.1 decoder to deliver the decoded bytes to us

                 ** from now on

                 */

                SEC_ASN1DecoderSetFilterProc(p7dcx->dcx,

                                             nss_cms_decoder_update_filter,

                                             p7dcx, (PRBool)(p7dcx->cb != NULL));

                /* we're right in front of the data */

                if (nss_cms_before_data(p7dcx) != SECSuccess) {

                    SEC_ASN1DecoderClearFilterProc(p7dcx->dcx);

                    /* stop all processing */

                    p7dcx->error = PORT_GetError();

                }

            }

            if (after && dest == &(cinfo->rawContent)) {

                /* we're right after of the data */

                if (nss_cms_after_data(p7dcx) != SECSuccess)

                    p7dcx->error = PORT_GetError();

                /* we don't need to see the contents anymore */

                SEC_ASN1DecoderClearFilterProc(p7dcx->dcx);

            }

        }

    } else {

        /* unsupported or unknown message type - fail  gracefully */

        p7dcx->error = SEC_ERROR_UNSUPPORTED_MESSAGE_TYPE;

    }

}

/*

 * nss_cms_before_data - set up the current encoder to receive data

 */

static SECStatus

nss_cms_before_data(NSSCMSDecoderContext *p7dcx)

{

    SECStatus rv;

    SECOidTag childtype;

    PLArenaPool *poolp;

    NSSCMSDecoderContext *childp7dcx;

    NSSCMSContentInfo *cinfo;

    const SEC_ASN1Template *template;

    void *mark = NULL;

    size_t size;

    poolp = p7dcx->cmsg->poolp;

    /* call _Decode_BeforeData handlers */

    switch (p7dcx->type) {

        case SEC_OID_PKCS7_SIGNED_DATA:

            /* we're decoding a signedData, so set up the digests */

            rv = NSS_CMSSignedData_Decode_BeforeData(p7dcx->content.signedData);

            break;

        case SEC_OID_PKCS7_DIGESTED_DATA:

            /* we're encoding a digestedData, so set up the digest */

            rv = NSS_CMSDigestedData_Decode_BeforeData(p7dcx->content.digestedData);

            break;

        case SEC_OID_PKCS7_ENVELOPED_DATA:

            rv = NSS_CMSEnvelopedData_Decode_BeforeData(

                p7dcx->content.envelopedData);

            break;

        case SEC_OID_PKCS7_ENCRYPTED_DATA:

            rv = NSS_CMSEncryptedData_Decode_BeforeData(

                p7dcx->content.encryptedData);

            break;

        default:

            rv = NSS_CMSGenericWrapperData_Decode_BeforeData(p7dcx->type,

                                                             p7dcx->content.genericData);

    }

    if (rv != SECSuccess)

        return SECFailure;

    /* ok, now we have a pointer to cinfo */

    /* find out what kind of data is encapsulated */

    cinfo = NSS_CMSContent_GetContentInfo(p7dcx->content.pointer, p7dcx->type);

    childtype = NSS_CMSContentInfo_GetContentTypeTag(cinfo);

    if (NSS_CMSType_IsData(childtype)) {

        cinfo->content.pointer = (void *)nss_cms_create_decoder_data(poolp);

        if (cinfo->content.pointer == NULL)

            /* set memory error */

            return SECFailure;

        p7dcx->childp7dcx = NULL;

        return SECSuccess;

    }

    /* set up inner decoder */

    if ((template = NSS_CMSUtil_GetTemplateByTypeTag(childtype)) == NULL)

        return SECFailure;

    childp7dcx = PORT_ZNew(NSSCMSDecoderContext);

    if (childp7dcx == NULL)

        return SECFailure;

    mark = PORT_ArenaMark(poolp);

    /* allocate space for the stuff we're creating */

    size = NSS_CMSUtil_GetSizeByTypeTag(childtype);

    childp7dcx->content.pointer = (void *)PORT_ArenaZAlloc(poolp, size);

    if (childp7dcx->content.pointer == NULL)

        goto loser;

    /* give the parent a copy of the pointer so that it doesn't get lost */

    cinfo->content.pointer = childp7dcx->content.pointer;

    /* start the child decoder */

    childp7dcx->dcx = SEC_ASN1DecoderStart(poolp, childp7dcx->content.pointer,

                                           template);

    if (childp7dcx->dcx == NULL)

        goto loser;

    /* the new decoder needs to notify, too */

    SEC_ASN1DecoderSetNotifyProc(childp7dcx->dcx, nss_cms_decoder_notify,

                                 childp7dcx);

    /* tell the parent decoder that it needs to feed us the content data */

    p7dcx->childp7dcx = childp7dcx;

    childp7dcx->type = childtype; /* our type */

    childp7dcx->cmsg = p7dcx->cmsg; /* backpointer to root message */

    /* should the child decoder encounter real data,

    ** it must give it to the caller

    */

    childp7dcx->cb = p7dcx->cb;

    childp7dcx->cb_arg = p7dcx->cb_arg;

    childp7dcx->first_decoded = PR_FALSE;

    childp7dcx->need_indefinite_finish = PR_FALSE;

    if (childtype == SEC_OID_PKCS7_SIGNED_DATA) {

        childp7dcx->first_decoded = PR_TRUE;

    }

    /* now set up the parent to hand decoded data to the next level decoder */

    p7dcx->cb = (NSSCMSContentCallback)NSS_CMSDecoder_Update;

    p7dcx->cb_arg = childp7dcx;

    PORT_ArenaUnmark(poolp, mark);

    return SECSuccess;

loser:

    if (mark)

        PORT_ArenaRelease(poolp, mark);

    PORT_Free(childp7dcx);

    p7dcx->childp7dcx = NULL;

    return SECFailure;

}

static SECStatus

nss_cms_after_data(NSSCMSDecoderContext *p7dcx)

{

    NSSCMSDecoderContext *childp7dcx;

    SECStatus rv = SECFailure;

    /* Handle last block. This is necessary to flush out the last bytes

     * of a possibly incomplete block */

    nss_cms_decoder_work_data(p7dcx, NULL, 0, PR_TRUE);

    /* finish any "inner" decoders - there's no more data coming... */

    if (p7dcx->childp7dcx != NULL) {

        childp7dcx = p7dcx->childp7dcx;

        if (childp7dcx->dcx != NULL) {

            /* we started and indefinite sequence somewhere, not complete it */

            if (childp7dcx->need_indefinite_finish) {

                static const char lbuf[2] = { 0, 0 };

                NSS_CMSDecoder_Update(childp7dcx, lbuf, sizeof(lbuf));

                childp7dcx->need_indefinite_finish = PR_FALSE;

            }

            if (SEC_ASN1DecoderFinish(childp7dcx->dcx) != SECSuccess) {

                /* do what? free content? */

                rv = SECFailure;

            } else {

                rv = nss_cms_after_end(childp7dcx);

            }

            if (rv != SECSuccess)

                goto done;

        }

        PORT_Free(p7dcx->childp7dcx);

        p7dcx->childp7dcx = NULL;

    }

    switch (p7dcx->type) {

        case SEC_OID_PKCS7_SIGNED_DATA:

            /* this will finish the digests and verify */

            rv = NSS_CMSSignedData_Decode_AfterData(p7dcx->content.signedData);

            break;

        case SEC_OID_PKCS7_ENVELOPED_DATA:

            rv = NSS_CMSEnvelopedData_Decode_AfterData(

                p7dcx->content.envelopedData);

            break;

        case SEC_OID_PKCS7_DIGESTED_DATA:

            rv = NSS_CMSDigestedData_Decode_AfterData(

                p7dcx->content.digestedData);

            break;

        case SEC_OID_PKCS7_ENCRYPTED_DATA:

            rv = NSS_CMSEncryptedData_Decode_AfterData(

                p7dcx->content.encryptedData);

            break;

        case SEC_OID_PKCS7_DATA:

            /* do nothing */

            break;

        default:

            rv = NSS_CMSGenericWrapperData_Decode_AfterData(p7dcx->type,

                                                            p7dcx->content.genericData);

            break;

    }

done:

    return rv;

}

static SECStatus

nss_cms_after_end(NSSCMSDecoderContext *p7dcx)

{

    SECStatus rv = SECSuccess;

    switch (p7dcx->type) {

        case SEC_OID_PKCS7_SIGNED_DATA:

            if (p7dcx->content.signedData)

                rv = NSS_CMSSignedData_Decode_AfterEnd(p7dcx->content.signedData);

            break;

        case SEC_OID_PKCS7_ENVELOPED_DATA:

            if (p7dcx->content.envelopedData)

                rv = NSS_CMSEnvelopedData_Decode_AfterEnd(

                    p7dcx->content.envelopedData);

            break;

        case SEC_OID_PKCS7_DIGESTED_DATA:

            if (p7dcx->content.digestedData)

                rv = NSS_CMSDigestedData_Decode_AfterEnd(

                    p7dcx->content.digestedData);

            break;

        case SEC_OID_PKCS7_ENCRYPTED_DATA:

            if (p7dcx->content.encryptedData)

                rv = NSS_CMSEncryptedData_Decode_AfterEnd(

                    p7dcx->content.encryptedData);

            break;

        case SEC_OID_PKCS7_DATA:

            break;

        default:

            rv = NSS_CMSGenericWrapperData_Decode_AfterEnd(p7dcx->type,

                                                           p7dcx->content.genericData);

            break;

    }

    return rv;

}

/*

 * nss_cms_decoder_work_data - handle decoded data bytes.

 *

 * This function either decrypts the data if needed, and/or calculates digests

 * on it, then either stores it or passes it on to the next level decoder.

 */

static void

nss_cms_decoder_work_data(NSSCMSDecoderContext *p7dcx,

                          const unsigned char *data, unsigned long len,

                          PRBool final)

{

    NSSCMSContentInfo *cinfo;

    unsigned char *buf = NULL;

    unsigned char *dest;

    unsigned int offset;

    SECStatus rv;

    /*

     * We should really have data to process, or we should be trying

     * to finish/flush the last block.  (This is an overly paranoid

     * check since all callers are in this file and simple inspection

     * proves they do it right.  But it could find a bug in future

     * modifications/development, that is why it is here.)

     */

    PORT_Assert((data != NULL && len) || final);

    cinfo = NSS_CMSContent_GetContentInfo(p7dcx->content.pointer, p7dcx->type);

    if (!cinfo) {

        /* The original programmer didn't expect this to happen */

        p7dcx->error = SEC_ERROR_LIBRARY_FAILURE;

        goto loser;

    }

    if (cinfo->privateInfo && cinfo->privateInfo->ciphcx != NULL) {

        /*

         * we are decrypting.

         *

         * XXX If we get an error, we do not want to do the digest or callback,

         * but we want to keep decoding.  Or maybe we want to stop decoding

         * altogether if there is a callback, because obviously we are not

         * sending the data back and they want to know that.

         */

        unsigned int outlen = 0; /* length of decrypted data */

        unsigned int buflen;     /* length available for decrypted data */

        /* find out about the length of decrypted data */

        buflen = NSS_CMSCipherContext_DecryptLength(cinfo->privateInfo->ciphcx, len, final);

        /*

         * it might happen that we did not provide enough data for a full

         * block (decryption unit), and that there is no output available

         */

        /* no output available, AND no input? */

        if (buflen == 0 && len == 0)

            goto loser; /* bail out */

        /*

         * have inner decoder: pass the data on (means inner content type is NOT data)

         * no inner decoder: we have DATA in here: either call callback or store

         */

        if (buflen != 0) {

            /* there will be some output - need to make room for it */

            /* allocate buffer from the heap */

            buf = (unsigned char *)PORT_Alloc(buflen);

            if (buf == NULL) {

                p7dcx->error = SEC_ERROR_NO_MEMORY;

                goto loser;

            }

        }

        /*

         * decrypt incoming data

         * buf can still be NULL here (and buflen == 0) here if we don't expect

         * any output (see above), but we still need to call NSS_CMSCipherContext_Decrypt to

         * keep track of incoming data

         */

        rv = NSS_CMSCipherContext_Decrypt(cinfo->privateInfo->ciphcx, buf, &outlen, buflen,

                                          data, len, final);

        if (rv != SECSuccess) {

            p7dcx->error = PORT_GetError();

            goto loser;

        }

        PORT_Assert(final || outlen == buflen);

        /* swap decrypted data in */

        data = buf;

        len = outlen;

    }

    if (len == 0)

        goto done; /* nothing more to do */

    /*

     * Update the running digests with plaintext bytes (if we need to).

     */

    if (cinfo->privateInfo && cinfo->privateInfo->digcx)

        NSS_CMSDigestContext_Update(cinfo->privateInfo->digcx, data, len);

    /* at this point, we have the plain decoded & decrypted data

    ** which is either more encoded DER (which we need to hand to the child

    ** decoder) or data we need to hand back to our caller

    */

    /* pass the content back to our caller or */

    /* feed our freshly decrypted and decoded data into child decoder */

    if (p7dcx->cb != NULL) {

        (*p7dcx->cb)(p7dcx->cb_arg, (const char *)data, len);

    }

#if 1

    else

#endif

        if (NSS_CMSContentInfo_GetContentTypeTag(cinfo) == SEC_OID_PKCS7_DATA) {

        /* store it in "inner" data item as well */

        /* find the DATA item in the encapsulated cinfo and store it there */

        NSSCMSDecoderData *decoderData =

            (NSSCMSDecoderData *)cinfo->content.pointer;

        SECItem *dataItem = &decoderData->data;

        offset = dataItem->len;

        if (dataItem->len + len > decoderData->totalBufferSize) {

            int needLen = (dataItem->len + len) * 2;

            dest = (unsigned char *)

                PORT_ArenaAlloc(p7dcx->cmsg->poolp, needLen);

            if (dest == NULL) {

                p7dcx->error = SEC_ERROR_NO_MEMORY;

                goto loser;

            }

            if (dataItem->len) {

                PORT_Memcpy(dest, dataItem->data, dataItem->len);

            }

            decoderData->totalBufferSize = needLen;

            dataItem->data = dest;

        }

        /* copy it in */

        PORT_Memcpy(dataItem->data + offset, data, len);

        dataItem->len += len;

    }

done:

loser:

    if (buf)

        PORT_Free(buf);

}

/*

 * nss_cms_decoder_update_filter - process ASN.1 data

 *

 * once we have set up a filter in nss_cms_decoder_notify(),

 * all data processed by the ASN.1 decoder is also passed through here.

 * we pass the content bytes (as opposed to length and tag bytes) on to

 * nss_cms_decoder_work_data().

 */

static void

nss_cms_decoder_update_filter(void *arg, const char *data, unsigned long len,

                              int depth, SEC_ASN1EncodingPart data_kind)

{

    NSSCMSDecoderContext *p7dcx;

    PORT_Assert(len); /* paranoia */

    if (len == 0)

        return;

    p7dcx = (NSSCMSDecoderContext *)arg;

    p7dcx->saw_contents = PR_TRUE;

    /* pass on the content bytes only */

    if (data_kind == SEC_ASN1_Contents)

        nss_cms_decoder_work_data(p7dcx, (const unsigned char *)data, len,

                                  PR_FALSE);

}

/*

 * NSS_CMSDecoder_Start - set up decoding of a DER-encoded CMS message

 *

 * "poolp" - pointer to arena for message, or NULL if new pool should be created

 * "cb", "cb_arg" - callback function and argument for delivery of inner content

 * "pwfn", pwfn_arg" - callback function for getting token password

 * "decrypt_key_cb", "decrypt_key_cb_arg" - callback function for getting bulk key for encryptedData

 */

NSSCMSDecoderContext *

NSS_CMSDecoder_Start(PLArenaPool *poolp,

                     NSSCMSContentCallback cb, void *cb_arg,

                     PK11PasswordFunc pwfn, void *pwfn_arg,

                     NSSCMSGetDecryptKeyCallback decrypt_key_cb,

                     void *decrypt_key_cb_arg)

{

    NSSCMSDecoderContext *p7dcx;

    NSSCMSMessage *cmsg;

    cmsg = NSS_CMSMessage_Create(poolp);

    if (cmsg == NULL)

        return NULL;

    NSS_CMSMessage_SetEncodingParams(cmsg, pwfn, pwfn_arg, decrypt_key_cb,

                                     decrypt_key_cb_arg, NULL, NULL);

    p7dcx = PORT_ZNew(NSSCMSDecoderContext);

    if (p7dcx == NULL) {

        NSS_CMSMessage_Destroy(cmsg);

        return NULL;

    }

    p7dcx->dcx = SEC_ASN1DecoderStart(cmsg->poolp, cmsg, NSSCMSMessageTemplate);

    if (p7dcx->dcx == NULL) {

        PORT_Free(p7dcx);

        NSS_CMSMessage_Destroy(cmsg);

        return NULL;

    }

    SEC_ASN1DecoderSetNotifyProc(p7dcx->dcx, nss_cms_decoder_notify, p7dcx);

    p7dcx->cmsg = cmsg;

    p7dcx->type = SEC_OID_UNKNOWN;

    p7dcx->cb = cb;

    p7dcx->cb_arg = cb_arg;

    p7dcx->first_decoded = PR_FALSE;

    p7dcx->need_indefinite_finish = PR_FALSE;

    return p7dcx;

}

/*

 * NSS_CMSDecoder_Update - feed DER-encoded data to decoder

 */

SECStatus

NSS_CMSDecoder_Update(NSSCMSDecoderContext *p7dcx, const char *buf,

                      unsigned long len)

{

    SECStatus rv = SECSuccess;

    if (p7dcx->dcx != NULL && p7dcx->error == 0) {

        /* if error is set already, don't bother */

        if ((p7dcx->type == SEC_OID_PKCS7_SIGNED_DATA) && (p7dcx->first_decoded == PR_TRUE) && (buf[0] == SEC_ASN1_INTEGER)) {

            /* Microsoft Windows 2008 left out the Sequence wrapping in some

             * of their kerberos replies. If we are here, we most likely are

             * dealing with one of those replies. Supply the Sequence wrap

             * as indefinite encoding (since we don't know the total length

             * yet) */

            static const char lbuf[2] =

                { SEC_ASN1_SEQUENCE | SEC_ASN1_CONSTRUCTED, 0x80 };

            rv = SEC_ASN1DecoderUpdate(p7dcx->dcx, lbuf, sizeof(lbuf));

            if (rv != SECSuccess) {

                goto loser;

            }

            /* ok, we're going to need the indefinite finish when we are done */

            p7dcx->need_indefinite_finish = PR_TRUE;

        }

        rv = SEC_ASN1DecoderUpdate(p7dcx->dcx, buf, len);

    }

loser:

    p7dcx->first_decoded = PR_FALSE;

    if (rv != SECSuccess) {

        p7dcx->error = PORT_GetError();

        PORT_Assert(p7dcx->error);

        if (p7dcx->error == 0)

            p7dcx->error = -1;

    }

    if (p7dcx->error == 0)

        return SECSuccess;

    /* there has been a problem, let's finish the decoder */

    if (p7dcx->dcx != NULL) {

        (void)SEC_ASN1DecoderFinish(p7dcx->dcx);

        p7dcx->dcx = NULL;

    }

    PORT_SetError(p7dcx->error);

    return SECFailure;

}

/*

 * NSS_CMSDecoder_Cancel - stop decoding in case of error

 */

void

NSS_CMSDecoder_Cancel(NSSCMSDecoderContext *p7dcx)

{

    if (p7dcx->dcx != NULL)

        (void)SEC_ASN1DecoderFinish(p7dcx->dcx);

    NSS_CMSMessage_Destroy(p7dcx->cmsg);

    PORT_Free(p7dcx);

}

/*

 * NSS_CMSDecoder_Finish - mark the end of inner content and finish decoding

 */

NSSCMSMessage *

NSS_CMSDecoder_Finish(NSSCMSDecoderContext *p7dcx)

{

    NSSCMSMessage *cmsg;

    cmsg = p7dcx->cmsg;

    if (p7dcx->dcx == NULL ||

        SEC_ASN1DecoderFinish(p7dcx->dcx) != SECSuccess ||

        nss_cms_after_end(p7dcx) != SECSuccess) {

        NSS_CMSMessage_Destroy(cmsg); /* get rid of pool if it's ours */

        cmsg = NULL;

    }

    PORT_Free(p7dcx);

    return cmsg;

}

NSSCMSMessage *

NSS_CMSMessage_CreateFromDER(SECItem *DERmessage,

                             NSSCMSContentCallback cb, void *cb_arg,

                             PK11PasswordFunc pwfn, void *pwfn_arg,

                             NSSCMSGetDecryptKeyCallback decrypt_key_cb,

                             void *decrypt_key_cb_arg)

{

    NSSCMSDecoderContext *p7dcx;

    /* first arg(poolp) == NULL => create our own pool */

    p7dcx = NSS_CMSDecoder_Start(NULL, cb, cb_arg, pwfn, pwfn_arg,

                                 decrypt_key_cb, decrypt_key_cb_arg);

    if (p7dcx == NULL)

        return NULL;

    NSS_CMSDecoder_Update(p7dcx, (char *)DERmessage->data, DERmessage->len);

    return NSS_CMSDecoder_Finish(p7dcx);

}