pjs/security/nss/lib/pkcs12/p12dec.c

/*
 * The contents of this file are subject to the Mozilla Public
 * License Version 1.1 (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.mozilla.org/MPL/
 * 
 * Software distributed under the License is distributed on an "AS
 * IS" basis, WITHOUT WARRANTY OF ANY KIND, either express or
 * implied. See the License for the specific language governing
 * rights and limitations under the License.
 * 
 * The Original Code is the Netscape security libraries.
 * 
 * The Initial Developer of the Original Code is Netscape
 * Communications Corporation.  Portions created by Netscape are 
 * Copyright (C) 1994-2000 Netscape Communications Corporation.  All
 * Rights Reserved.
 * 
 * Contributor(s):
 * 
 * Alternatively, the contents of this file may be used under the
 * terms of the GNU General Public License Version 2 or later (the
 * "GPL"), in which case the provisions of the GPL are applicable 
 * instead of those above.  If you wish to allow use of your 
 * version of this file only under the terms of the GPL and not to
 * allow others to use your version of this file under the MPL,
 * indicate your decision by deleting the provisions above and
 * replace them with the notice and other provisions required by
 * the GPL.  If you do not delete the provisions above, a recipient
 * may use your version of this file under either the MPL or the
 * GPL.
 */

#include "pkcs12.h"
#include "plarena.h"
#include "secpkcs7.h"
#include "p12local.h"
#include "secoid.h"
#include "secitem.h"
#include "secport.h"
#include "secasn1.h"
#include "secder.h"
#include "secerr.h"
#include "cert.h"
#include "certdb.h"
#include "p12plcy.h"
#include "p12.h" 
#include "secpkcs5.h" 

/* PFX extraction and validation routines */

/* decode the DER encoded PFX item.  if unable to decode, check to see if it
 * is an older PFX item.  If that fails, assume the file was not a valid
 * pfx file.
 * the returned pfx structure should be destroyed using SEC_PKCS12DestroyPFX
 */
static SEC_PKCS12PFXItem *
sec_pkcs12_decode_pfx(SECItem *der_pfx)
{
    SEC_PKCS12PFXItem *pfx;
    SECStatus rv;

    if(der_pfx == NULL) {
	return NULL;
    }

    /* allocate the space for a new PFX item */
    pfx = sec_pkcs12_new_pfx();
    if(pfx == NULL) {
	return NULL;
    }

    rv = SEC_ASN1DecodeItem(pfx->poolp, pfx, SEC_PKCS12PFXItemTemplate, 
    			    der_pfx);

    /* if a failure occurred, check for older version...
     * we also get rid of the old pfx structure, because we don't
     * know where it failed and what data in may contain
     */
    if(rv != SECSuccess) {
	SEC_PKCS12DestroyPFX(pfx);
	pfx = sec_pkcs12_new_pfx();
	if(pfx == NULL) {
	    return NULL;
	}
	rv = SEC_ASN1DecodeItem(pfx->poolp, pfx, SEC_PKCS12PFXItemTemplate_OLD, 
				der_pfx);
	if(rv != SECSuccess) {
	    PORT_SetError(SEC_ERROR_PKCS12_DECODING_PFX);
	    PORT_FreeArena(pfx->poolp, PR_TRUE);
	    return NULL;
	}
	pfx->old = PR_TRUE;
	SGN_CopyDigestInfo(pfx->poolp, &pfx->macData.safeMac, &pfx->old_safeMac);
	SECITEM_CopyItem(pfx->poolp, &pfx->macData.macSalt, &pfx->old_macSalt);
    } else {
	pfx->old = PR_FALSE;
    }

    /* convert bit string from bits to bytes */
    pfx->macData.macSalt.len /= 8;

    return pfx;
}

/* validate the integrity MAC used in the PFX.  The MAC is generated
 * per the PKCS 12 document.  If the MAC is incorrect, it is most likely
 * due to an invalid password.
 * pwitem is the integrity password
 * pfx is the decoded pfx item
 */
static PRBool 
sec_pkcs12_check_pfx_mac(SEC_PKCS12PFXItem *pfx,
			 SECItem *pwitem)
{
    SECItem *key = NULL, *mac = NULL, *data = NULL;
    SECItem *vpwd = NULL;
    SECOidTag algorithm;
    PRBool ret = PR_FALSE;

    if(pfx == NULL) {
	return PR_FALSE;
    }

    algorithm = SECOID_GetAlgorithmTag(&pfx->macData.safeMac.digestAlgorithm);
    switch(algorithm) {
	/* only SHA1 hashing supported as a MACing algorithm */
	case SEC_OID_SHA1:
	    if(pfx->old == PR_FALSE) {
		pfx->swapUnicode = PR_FALSE;
	    }

recheckUnicodePassword:
	    vpwd = sec_pkcs12_create_virtual_password(pwitem, 
	    					&pfx->macData.macSalt, 
						pfx->swapUnicode);
	    if(vpwd == NULL) {
		return PR_FALSE;
	    }

	    key = sec_pkcs12_generate_key_from_password(algorithm,
						&pfx->macData.macSalt, 
						(pfx->old ? pwitem : vpwd));
	    /* free vpwd only for newer PFX */
	    if(vpwd) {
		SECITEM_ZfreeItem(vpwd, PR_TRUE);
	    }
	    if(key == NULL) {
		return PR_FALSE;
	    }

	    data = SEC_PKCS7GetContent(&pfx->authSafe);
	    if(data == NULL) {
		break;
	    }

	    /* check MAC */
	    mac = sec_pkcs12_generate_mac(key, data, pfx->old);
	    ret = PR_TRUE;
	    if(mac) {
		SECItem *safeMac = &pfx->macData.safeMac.digest;
		if(SECITEM_CompareItem(mac, safeMac) != SECEqual) {

		    /* if we encounter an invalid mac, lets invert the
		     * password in case of unicode changes 
		     */
		    if(((!pfx->old) && pfx->swapUnicode) || (pfx->old)){
			PORT_SetError(SEC_ERROR_PKCS12_INVALID_MAC);
			ret = PR_FALSE;
		    } else {
			SECITEM_ZfreeItem(mac, PR_TRUE);
			pfx->swapUnicode = PR_TRUE;
			goto recheckUnicodePassword;
		    }
		} 
		SECITEM_ZfreeItem(mac, PR_TRUE);
	    } else {
		ret = PR_FALSE;
	    }
	    break;
	default:
	    PORT_SetError(SEC_ERROR_PKCS12_UNSUPPORTED_MAC_ALGORITHM);
	    ret = PR_FALSE;
	    break;
    }

    /* let success fall through */
    if(key != NULL)
	SECITEM_ZfreeItem(key, PR_TRUE);

    return ret;
}

/* check the validity of the pfx structure.  we currently only support
 * password integrity mode, so we check the MAC.
 */
static PRBool 
sec_pkcs12_validate_pfx(SEC_PKCS12PFXItem *pfx, 
			SECItem *pwitem)
{
    SECOidTag contentType;

    contentType = SEC_PKCS7ContentType(&pfx->authSafe);
    switch(contentType)
    {
	case SEC_OID_PKCS7_DATA:
	    return sec_pkcs12_check_pfx_mac(pfx, pwitem);
	    break;
	case SEC_OID_PKCS7_SIGNED_DATA:
	default:
	    PORT_SetError(SEC_ERROR_PKCS12_UNSUPPORTED_TRANSPORT_MODE);
	    break;
    }

    return PR_FALSE;
}

/* decode and return the valid PFX.  if the PFX item is not valid,
 * NULL is returned.
 */
static SEC_PKCS12PFXItem *
sec_pkcs12_get_pfx(SECItem *pfx_data, 
		   SECItem *pwitem)
{
    SEC_PKCS12PFXItem *pfx;
    PRBool valid_pfx;

    if((pfx_data == NULL) || (pwitem == NULL)) {
	return NULL;
    }

    pfx = sec_pkcs12_decode_pfx(pfx_data);
    if(pfx == NULL) {
	return NULL;
    }

    valid_pfx = sec_pkcs12_validate_pfx(pfx, pwitem);
    if(valid_pfx != PR_TRUE) {
	SEC_PKCS12DestroyPFX(pfx);
	pfx = NULL;
    }

    return pfx;
}

/* authenticated safe decoding, validation, and access routines
 */

/* convert dogbert beta 3 authenticated safe structure to a post
 * beta three structure, so that we don't have to change more routines.
 */
static SECStatus
sec_pkcs12_convert_old_auth_safe(SEC_PKCS12AuthenticatedSafe *asafe)
{
    SEC_PKCS12Baggage *baggage;
    SEC_PKCS12BaggageItem *bag;
    SECStatus rv = SECSuccess;

    if(asafe->old_baggage.espvks == NULL) {
	/* XXX should the ASN1 engine produce a single NULL element list
	 * rather than setting the pointer to NULL?  
	 * There is no need to return an error -- assume that the list
	 * was empty.
	 */
	return SECSuccess;
    }

    baggage = sec_pkcs12_create_baggage(asafe->poolp);
    if(!baggage) {
	return SECFailure;
    }
    bag = sec_pkcs12_create_external_bag(baggage);
    if(!bag) {
	return SECFailure;
    }

    PORT_Memcpy(&asafe->baggage, baggage, sizeof(SEC_PKCS12Baggage));

    /* if there are shrouded keys, append them to the bag */
    rv = SECSuccess;
    if(asafe->old_baggage.espvks[0] != NULL) {
	int nEspvk = 0;
	rv = SECSuccess;
	while((asafe->old_baggage.espvks[nEspvk] != NULL) && 
		(rv == SECSuccess)) {
	    rv = sec_pkcs12_append_shrouded_key(bag, 
	    				asafe->old_baggage.espvks[nEspvk]);
	    nEspvk++;
	}
    }

    return rv;
}    

/* decodes the authenticated safe item.  a return of NULL indicates
 * an error.  however, the error will have occured either in memory
 * allocation or in decoding the authenticated safe.
 *
 * if an old PFX item has been found, we want to convert the
 * old authenticated safe to the new one.
 */
static SEC_PKCS12AuthenticatedSafe *
sec_pkcs12_decode_authenticated_safe(SEC_PKCS12PFXItem *pfx) 
{
    SECItem *der_asafe = NULL;
    SEC_PKCS12AuthenticatedSafe *asafe = NULL;
    SECStatus rv;

    if(pfx == NULL) {
	return NULL;
    }

    der_asafe = SEC_PKCS7GetContent(&pfx->authSafe);
    if(der_asafe == NULL) {
	/* XXX set error ? */
	goto loser;
    }

    asafe = sec_pkcs12_new_asafe(pfx->poolp);
    if(asafe == NULL) {
	goto loser;
    }

    if(pfx->old == PR_FALSE) {
	rv = SEC_ASN1DecodeItem(pfx->poolp, asafe, 
			 	SEC_PKCS12AuthenticatedSafeTemplate, 
			 	der_asafe);
	asafe->old = PR_FALSE;
	asafe->swapUnicode = pfx->swapUnicode;
    } else {
	/* handle beta exported files */
	rv = SEC_ASN1DecodeItem(pfx->poolp, asafe, 
				SEC_PKCS12AuthenticatedSafeTemplate_OLD,
				der_asafe);
	asafe->safe = &(asafe->old_safe);
	rv = sec_pkcs12_convert_old_auth_safe(asafe);
	asafe->old = PR_TRUE;
    }

    if(rv != SECSuccess) {
	goto loser;
    }

    asafe->poolp = pfx->poolp;
    
    return asafe;

loser:
    return NULL;
}

/* validates the safe within the authenticated safe item.  
 * in order to be valid:
 *  1.  the privacy salt must be present
 *  2.  the encryption algorithm must be supported (including
 *	export policy)
 * PR_FALSE indicates an error, PR_TRUE indicates a valid safe
 */
static PRBool 
sec_pkcs12_validate_encrypted_safe(SEC_PKCS12AuthenticatedSafe *asafe)
{
    PRBool valid = PR_FALSE;
    SECAlgorithmID *algid;

    if(asafe == NULL) {
	return PR_FALSE;
    }

    /* if mode is password privacy, then privacySalt is assumed
     * to be non-zero.
     */
    if(asafe->privacySalt.len != 0) {
	valid = PR_TRUE;
	asafe->privacySalt.len /= 8;
    } else {
	PORT_SetError(SEC_ERROR_PKCS12_CORRUPT_PFX_STRUCTURE);
	return PR_FALSE;
    }

    /* until spec changes, content will have between 2 and 8 bytes depending
     * upon the algorithm used if certs are unencrypted...
     * also want to support case where content is empty -- which we produce 
     */ 
    if(SEC_PKCS7IsContentEmpty(asafe->safe, 8) == PR_TRUE) {
	asafe->emptySafe = PR_TRUE;
	return PR_TRUE;
    }

    asafe->emptySafe = PR_FALSE;

    /* make sure that a pbe algorithm is being used */
    algid = SEC_PKCS7GetEncryptionAlgorithm(asafe->safe);
    if(algid != NULL) {
	if(SEC_PKCS5IsAlgorithmPBEAlg(algid)) {
	    valid = SEC_PKCS12DecryptionAllowed(algid);

	    if(valid == PR_FALSE) {
		PORT_SetError(SEC_ERROR_BAD_EXPORT_ALGORITHM);
	    }
	} else {
	    PORT_SetError(SEC_ERROR_PKCS12_UNSUPPORTED_PBE_ALGORITHM);
	    valid = PR_FALSE;
	}
    } else {
	valid = PR_FALSE;
	PORT_SetError(SEC_ERROR_PKCS12_UNSUPPORTED_PBE_ALGORITHM);
    }

    return valid;
}

/* validates authenticates safe:
 *  1.  checks that the version is supported
 *  2.  checks that only password privacy mode is used (currently)
 *  3.  further, makes sure safe has appropriate policies per above function
 * PR_FALSE indicates failure.
 */
static PRBool 
sec_pkcs12_validate_auth_safe(SEC_PKCS12AuthenticatedSafe *asafe)
{
    PRBool valid = PR_TRUE;
    SECOidTag safe_type;
    int version;

    if(asafe == NULL) {
	return PR_FALSE;
    }

    /* check version, since it is default it may not be present.
     * therefore, assume ok
     */
    if((asafe->version.len > 0) && (asafe->old == PR_FALSE)) {
	version = DER_GetInteger(&asafe->version);
	if(version > SEC_PKCS12_PFX_VERSION) {
	    PORT_SetError(SEC_ERROR_PKCS12_UNSUPPORTED_VERSION);
	    return PR_FALSE;
	}
    }

    /* validate password mode is being used */
    safe_type = SEC_PKCS7ContentType(asafe->safe);
    switch(safe_type)
    {
	case SEC_OID_PKCS7_ENCRYPTED_DATA:
	    valid = sec_pkcs12_validate_encrypted_safe(asafe);
	    break;
	case SEC_OID_PKCS7_ENVELOPED_DATA:
	default:
	    PORT_SetError(SEC_ERROR_PKCS12_UNSUPPORTED_TRANSPORT_MODE);
	    valid = PR_FALSE;
	    break;
    }

    return valid;
}

/* retrieves the authenticated safe item from the PFX item
 *  before returning the authenticated safe, the validity of the
 *  authenticated safe is checked and if valid, returned.
 * a return of NULL indicates that an error occured.
 */
static SEC_PKCS12AuthenticatedSafe *
sec_pkcs12_get_auth_safe(SEC_PKCS12PFXItem *pfx)
{
    SEC_PKCS12AuthenticatedSafe *asafe;
    PRBool valid_safe;

    if(pfx == NULL) {
	return NULL;
    }

    asafe = sec_pkcs12_decode_authenticated_safe(pfx);
    if(asafe == NULL) {
	return NULL;
    }

    valid_safe = sec_pkcs12_validate_auth_safe(asafe);
    if(valid_safe != PR_TRUE) {
	asafe = NULL;
    } else if(asafe) {
	asafe->baggage.poolp = asafe->poolp;
    }

    return asafe;
}

/* decrypts the authenticated safe.
 * a return of anything but SECSuccess indicates an error.  the
 * password is not known to be valid until the call to the 
 * function sec_pkcs12_get_safe_contents.  If decoding the safe
 * fails, it is assumed the password was incorrect and the error
 * is set then.  any failure here is assumed to be due to 
 * internal problems in SEC_PKCS7DecryptContents or below.
 */
static SECStatus
sec_pkcs12_decrypt_auth_safe(SEC_PKCS12AuthenticatedSafe *asafe, 
			     SECItem *pwitem,
			     void *wincx)
{
    SECStatus rv = SECFailure;
    SECItem *vpwd = NULL;

    if((asafe == NULL) || (pwitem == NULL)) {
	return SECFailure;
    }

    if(asafe->old == PR_FALSE) {
	vpwd = sec_pkcs12_create_virtual_password(pwitem, &asafe->privacySalt,
						 asafe->swapUnicode);
	if(vpwd == NULL) {
	    return SECFailure;
	}
    }

    rv = SEC_PKCS7DecryptContents(asafe->poolp, asafe->safe, 
    				  (asafe->old ? pwitem : vpwd), wincx);

    if(asafe->old == PR_FALSE) {
	SECITEM_ZfreeItem(vpwd, PR_TRUE);
    }

    return rv;
}

/* extract the safe from the authenticated safe.
 *  if we are unable to decode the safe, then it is likely that the 
 *  safe has not been decrypted or the password used to decrypt
 *  the safe was invalid.  we assume that the password was invalid and
 *  set an error accordingly.
 * a return of NULL indicates that an error occurred.
 */
static SEC_PKCS12SafeContents *
sec_pkcs12_get_safe_contents(SEC_PKCS12AuthenticatedSafe *asafe)
{
    SECItem *src = NULL;
    SEC_PKCS12SafeContents *safe = NULL;
    SECStatus rv = SECFailure;

    if(asafe == NULL) {
	return NULL;
    }

    safe = (SEC_PKCS12SafeContents *)PORT_ArenaZAlloc(asafe->poolp, 
	    					sizeof(SEC_PKCS12SafeContents));
    if(safe == NULL) {
	return NULL;
    }
    safe->poolp = asafe->poolp;
    safe->old = asafe->old;
    safe->swapUnicode = asafe->swapUnicode;

    src = SEC_PKCS7GetContent(asafe->safe);
    if(src != NULL) {
	const SEC_ASN1Template *theTemplate;
	if(asafe->old != PR_TRUE) {
	    theTemplate = SEC_PKCS12SafeContentsTemplate;
	} else {
	    theTemplate = SEC_PKCS12SafeContentsTemplate_OLD;
	}

	rv = SEC_ASN1DecodeItem(asafe->poolp, safe, theTemplate, src);

	/* if we could not decode the item, password was probably invalid */
	if(rv != SECSuccess) {
	    safe = NULL;
	    PORT_SetError(SEC_ERROR_PKCS12_PRIVACY_PASSWORD_INCORRECT);
	}
    } else {
	PORT_SetError(SEC_ERROR_PKCS12_CORRUPT_PFX_STRUCTURE);
	rv = SECFailure;
    }

    return safe;
}

/* import PFX item 
 * der_pfx is the der encoded pfx structure
 * pbef and pbearg are the integrity/encryption password call back
 * ncCall is the nickname collision calllback
 * slot is the destination token
 * wincx window handler
 *
 * on error, error code set and SECFailure returned 
 */
SECStatus
SEC_PKCS12PutPFX(SECItem *der_pfx, SECItem *pwitem,
		 SEC_PKCS12NicknameCollisionCallback ncCall,
		 PK11SlotInfo *slot,
		 void *wincx)
{
    SEC_PKCS12PFXItem *pfx;
    SEC_PKCS12AuthenticatedSafe *asafe;
    SEC_PKCS12SafeContents *safe_contents = NULL;
    SECStatus rv;

    if(!der_pfx || !pwitem || !slot) {
	return SECFailure;
    }

    /* decode and validate each section */
    rv = SECFailure;

    pfx = sec_pkcs12_get_pfx(der_pfx, pwitem);
    if(pfx != NULL) {
	asafe = sec_pkcs12_get_auth_safe(pfx);
	if(asafe != NULL) {

	    /* decrypt safe -- only if not empty */
	    if(asafe->emptySafe != PR_TRUE) {
		rv = sec_pkcs12_decrypt_auth_safe(asafe, pwitem, wincx);
		if(rv == SECSuccess) {
		    safe_contents = sec_pkcs12_get_safe_contents(asafe);
		    if(safe_contents == NULL) {
			rv = SECFailure;
		    }
		}
	    } else {
		safe_contents = sec_pkcs12_create_safe_contents(asafe->poolp);
		safe_contents->swapUnicode = pfx->swapUnicode;
		if(safe_contents == NULL) {
		    rv = SECFailure;
		} else {
		    rv = SECSuccess;
		}
	    }

	    /* get safe contents and begin import */
	    if(rv == SECSuccess) {
		SEC_PKCS12DecoderContext *p12dcx;

		p12dcx = sec_PKCS12ConvertOldSafeToNew(pfx->poolp, slot,
					pfx->swapUnicode,
					pwitem, wincx, safe_contents,
					&asafe->baggage);
		if(!p12dcx) {
		    rv = SECFailure;
		    goto loser;
		}

		if(SEC_PKCS12DecoderValidateBags(p12dcx, ncCall) 
				!= SECSuccess) {
		    rv = SECFailure;
		    goto loser;
		}

		rv = SEC_PKCS12DecoderImportBags(p12dcx);
	    }

	}
    }

loser:

    if(pfx) {
	SEC_PKCS12DestroyPFX(pfx);
    }

    return rv;
}

PRBool 
SEC_PKCS12ValidData(char *buf, int bufLen, long int totalLength)
{
    int lengthLength;

    PRBool valid = PR_FALSE;

    if(buf == NULL) {
	return PR_FALSE;
    }

    /* check for constructed sequence identifier tag */
    if(*buf == (SEC_ASN1_CONSTRUCTED | SEC_ASN1_SEQUENCE)) {
	totalLength--;   /* header byte taken care of */
	buf++;

	lengthLength = (long int)SEC_ASN1LengthLength(totalLength - 1);
	if(totalLength > 0x7f) {
	    lengthLength--;
	    *buf &= 0x7f;  /* remove bit 8 indicator */
	    if((*buf - (char)lengthLength) == 0) {
		valid = PR_TRUE;
	    }
	} else {
	    lengthLength--;
	    if((*buf - (char)lengthLength) == 0) {
		valid = PR_TRUE;
	    }
	}
    }

    return valid;
}