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: #include "blapit.h"
michael@0: #include "secport.h"
michael@0: #include "secerr.h"
michael@0: 
michael@0: /*
michael@0:  * Prepare a buffer for any padded CBC encryption algorithm, growing to the 
michael@0:  * appropriate boundary and filling with the appropriate padding.
michael@0:  * blockSize must be a power of 2.
michael@0:  *
michael@0:  * NOTE: If arena is non-NULL, we re-allocate from there, otherwise
michael@0:  * we assume (and use) XP memory (re)allocation.
michael@0:  */
michael@0: unsigned char *
michael@0: CBC_PadBuffer(PLArenaPool *arena, unsigned char *inbuf, unsigned int inlen,
michael@0: 	      unsigned int *outlen, int blockSize)
michael@0: {
michael@0:     unsigned char *outbuf;
michael@0:     unsigned int   des_len;
michael@0:     unsigned int   i;
michael@0:     unsigned char  des_pad_len;
michael@0: 
michael@0:     /*
michael@0:      * We need from 1 to blockSize bytes -- we *always* grow.
michael@0:      * The extra bytes contain the value of the length of the padding:
michael@0:      * if we have 2 bytes of padding, then the padding is "0x02, 0x02".
michael@0:      */
michael@0:     des_len = (inlen + blockSize) & ~(blockSize - 1);
michael@0: 
michael@0:     if (arena != NULL) {
michael@0: 	outbuf = (unsigned char*)PORT_ArenaGrow (arena, inbuf, inlen, des_len);
michael@0:     } else {
michael@0: 	outbuf = (unsigned char*)PORT_Realloc (inbuf, des_len);
michael@0:     }
michael@0: 
michael@0:     if (outbuf == NULL) {
michael@0: 	PORT_SetError (SEC_ERROR_NO_MEMORY);
michael@0: 	return NULL;
michael@0:     }
michael@0: 
michael@0:     des_pad_len = des_len - inlen;
michael@0:     for (i = inlen; i < des_len; i++)
michael@0: 	outbuf[i] = des_pad_len;
michael@0: 
michael@0:     *outlen = des_len;
michael@0:     return outbuf;
michael@0: }