michael@0: /* This Source Code Form is subject to the terms of the Mozilla Public
michael@0:  * License, v. 2.0. If a copy of the MPL was not distributed with this
michael@0:  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
michael@0: 
michael@0: #include "secder.h"
michael@0: #include "secerr.h"
michael@0: 
michael@0: static PRUint32
michael@0: der_indefinite_length(unsigned char *buf, unsigned char *end)
michael@0: {
michael@0:     PRUint32 len, ret, dataLen;
michael@0:     unsigned char tag, lenCode;
michael@0:     int dataLenLen;
michael@0: 
michael@0:     len = 0;
michael@0:     while ( 1 ) {
michael@0: 	if ((buf + 2) > end) {
michael@0: 	    return(0);
michael@0: 	}
michael@0: 	
michael@0: 	tag = *buf++;
michael@0: 	lenCode = *buf++;
michael@0: 	len += 2;
michael@0: 	
michael@0: 	if ( ( tag == 0 ) && ( lenCode == 0 ) ) {
michael@0: 	    return(len);
michael@0: 	}
michael@0: 	
michael@0: 	if ( lenCode == 0x80 ) {	/* indefinite length */
michael@0: 	    ret = der_indefinite_length(buf, end); /* recurse to find length */
michael@0: 	    if (ret == 0)
michael@0: 		return 0;
michael@0: 	    len += ret;
michael@0: 	    buf += ret;
michael@0: 	} else {			/* definite length */
michael@0: 	    if (lenCode & 0x80) {
michael@0: 		/* Length of data is in multibyte format */
michael@0: 		dataLenLen = lenCode & 0x7f;
michael@0: 		switch (dataLenLen) {
michael@0: 		  case 1:
michael@0: 		    dataLen = buf[0];
michael@0: 		    break;
michael@0: 		  case 2:
michael@0: 		    dataLen = (buf[0]<<8)|buf[1];
michael@0: 		    break;
michael@0: 		  case 3:
michael@0: 		    dataLen = ((unsigned long)buf[0]<<16)|(buf[1]<<8)|buf[2];
michael@0: 		    break;
michael@0: 		  case 4:
michael@0: 		    dataLen = ((unsigned long)buf[0]<<24)|
michael@0: 			((unsigned long)buf[1]<<16)|(buf[2]<<8)|buf[3];
michael@0: 		    break;
michael@0: 		  default:
michael@0: 		    PORT_SetError(SEC_ERROR_BAD_DER);
michael@0: 		    return SECFailure;
michael@0: 		}
michael@0: 	    } else {
michael@0: 		/* Length of data is in single byte */
michael@0: 		dataLen = lenCode;
michael@0: 		dataLenLen = 0;
michael@0: 	    }
michael@0: 
michael@0: 	    /* skip this item */
michael@0: 	    buf = buf + dataLenLen + dataLen;
michael@0: 	    len = len + dataLenLen + dataLen;
michael@0: 	}
michael@0:     }
michael@0: }
michael@0: 
michael@0: /*
michael@0: ** Capture the next thing in the buffer.
michael@0: ** Returns the length of the header and the length of the contents.
michael@0: */
michael@0: static SECStatus
michael@0: der_capture(unsigned char *buf, unsigned char *end,
michael@0: 	    int *header_len_p, PRUint32 *contents_len_p)
michael@0: {
michael@0:     unsigned char *bp;
michael@0:     unsigned char whole_tag;
michael@0:     PRUint32 contents_len;
michael@0:     int tag_number;
michael@0: 
michael@0:     if ((buf + 2) > end) {
michael@0: 	*header_len_p = 0;
michael@0: 	*contents_len_p = 0;
michael@0: 	if (buf == end)
michael@0: 	    return SECSuccess;
michael@0: 	return SECFailure;
michael@0:     }
michael@0: 
michael@0:     bp = buf;
michael@0: 
michael@0:     /* Get tag and verify that it is ok. */
michael@0:     whole_tag = *bp++;
michael@0:     tag_number = whole_tag & DER_TAGNUM_MASK;
michael@0: 
michael@0:     /*
michael@0:      * XXX This code does not (yet) handle the high-tag-number form!
michael@0:      */
michael@0:     if (tag_number == DER_HIGH_TAG_NUMBER) {
michael@0: 	PORT_SetError(SEC_ERROR_BAD_DER);
michael@0: 	return SECFailure;
michael@0:     }
michael@0: 
michael@0:     if ((whole_tag & DER_CLASS_MASK) == DER_UNIVERSAL) {
michael@0: 	/* Check that the universal tag number is one we implement.  */
michael@0: 	switch (tag_number) {
michael@0: 	  case DER_BOOLEAN:
michael@0: 	  case DER_INTEGER:
michael@0: 	  case DER_BIT_STRING:
michael@0: 	  case DER_OCTET_STRING:
michael@0: 	  case DER_NULL:
michael@0: 	  case DER_OBJECT_ID:
michael@0: 	  case DER_SEQUENCE:
michael@0: 	  case DER_SET:
michael@0: 	  case DER_PRINTABLE_STRING:
michael@0: 	  case DER_T61_STRING:
michael@0: 	  case DER_IA5_STRING:
michael@0: 	  case DER_VISIBLE_STRING:
michael@0: 	  case DER_UTC_TIME:
michael@0: 	  case 0:			/* end-of-contents tag */
michael@0: 	    break;
michael@0: 	  default:
michael@0: 	    PORT_SetError(SEC_ERROR_BAD_DER);
michael@0: 	    return SECFailure;
michael@0: 	}
michael@0:     }
michael@0: 
michael@0:     /*
michael@0:      * Get first byte of length code (might contain entire length, might not).
michael@0:      */
michael@0:     contents_len = *bp++;
michael@0: 
michael@0:     /*
michael@0:      * If the high bit is set, then the length is in multibyte format,
michael@0:      * or the thing has an indefinite-length.
michael@0:      */
michael@0:     if (contents_len & 0x80) {
michael@0: 	int bytes_of_encoded_len;
michael@0: 
michael@0: 	bytes_of_encoded_len = contents_len & 0x7f;
michael@0: 	contents_len = 0;
michael@0: 
michael@0: 	switch (bytes_of_encoded_len) {
michael@0: 	  case 4:
michael@0: 	    contents_len |= *bp++;
michael@0: 	    contents_len <<= 8;
michael@0: 	    /* fallthru */
michael@0: 	  case 3:
michael@0: 	    contents_len |= *bp++;
michael@0: 	    contents_len <<= 8;
michael@0: 	    /* fallthru */
michael@0: 	  case 2:
michael@0: 	    contents_len |= *bp++;
michael@0: 	    contents_len <<= 8;
michael@0: 	    /* fallthru */
michael@0: 	  case 1:
michael@0: 	    contents_len |= *bp++;
michael@0: 	    break;
michael@0: 
michael@0: 	  case 0:
michael@0: 	    contents_len = der_indefinite_length (bp, end);
michael@0: 	    if (contents_len)
michael@0: 		break;
michael@0: 	    /* fallthru */
michael@0: 	  default:
michael@0: 	    PORT_SetError(SEC_ERROR_BAD_DER);
michael@0: 	    return SECFailure;
michael@0: 	}
michael@0:     }
michael@0: 
michael@0:     if ((bp + contents_len) > end) {
michael@0: 	/* Ran past end of buffer */
michael@0: 	PORT_SetError(SEC_ERROR_BAD_DER);
michael@0: 	return SECFailure;
michael@0:     }
michael@0: 
michael@0:     *header_len_p = bp - buf;
michael@0:     *contents_len_p = contents_len;
michael@0: 
michael@0:     return SECSuccess;
michael@0: }
michael@0: 
michael@0: SECStatus
michael@0: DER_Lengths(SECItem *item, int *header_len_p, PRUint32 *contents_len_p)
michael@0: {
michael@0:     return(der_capture(item->data, &item->data[item->len], header_len_p,
michael@0: 		       contents_len_p));
michael@0: }