src/lib/libcrypto/des/enc_writ.c

/* $OpenBSD: enc_writ.c,v 1.18 2024/03/29 01:47:29 joshua Exp $ */
/* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)
 * All rights reserved.
 *
 * This package is an SSL implementation written
 * by Eric Young (eay@cryptsoft.com).
 * The implementation was written so as to conform with Netscapes SSL.
 *
 * This library is free for commercial and non-commercial use as long as
 * the following conditions are aheared to.  The following conditions
 * apply to all code found in this distribution, be it the RC4, RSA,
 * lhash, DES, etc., code; not just the SSL code.  The SSL documentation
 * included with this distribution is covered by the same copyright terms
 * except that the holder is Tim Hudson (tjh@cryptsoft.com).
 *
 * Copyright remains Eric Young's, and as such any Copyright notices in
 * the code are not to be removed.
 * If this package is used in a product, Eric Young should be given attribution
 * as the author of the parts of the library used.
 * This can be in the form of a textual message at program startup or
 * in documentation (online or textual) provided with the package.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *    "This product includes cryptographic software written by
 *     Eric Young (eay@cryptsoft.com)"
 *    The word 'cryptographic' can be left out if the rouines from the library
 *    being used are not cryptographic related :-).
 * 4. If you include any Windows specific code (or a derivative thereof) from
 *    the apps directory (application code) you must include an acknowledgement:
 *    "This product includes software written by Tim Hudson (tjh@cryptsoft.com)"
 *
 * THIS SOFTWARE IS PROVIDED BY ERIC YOUNG ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 *
 * The licence and distribution terms for any publically available version or
 * derivative of this code cannot be changed.  i.e. this code cannot simply be
 * copied and put under another distribution licence
 * [including the GNU Public Licence.]
 */

#include <errno.h>
#include <stdio.h>
#include <stdlib.h>
#include <time.h>

#include <openssl/opensslconf.h>

#include "des_local.h"

/*
 * WARNINGS:
 *
 *  -  The data format used by DES_enc_write() and DES_enc_read()
 *     has a cryptographic weakness: When asked to write more
 *     than MAXWRITE bytes, DES_enc_write will split the data
 *     into several chunks that are all encrypted
 *     using the same IV.  So don't use these functions unless you
 *     are sure you know what you do (in which case you might
 *     not want to use them anyway).
 *
 *  -  This code cannot handle non-blocking sockets.
 */

int
DES_enc_write(int fd, const void *_buf, int len,
    DES_key_schedule *sched, DES_cblock *iv)
{
#ifdef _LIBC
	extern unsigned long time();
	extern int write();
#endif
	const unsigned char *buf = _buf;
	long rnum;
	int i, j, k, outnum;
	static unsigned char *outbuf = NULL;
	unsigned char shortbuf[8];
	unsigned char *p;
	const unsigned char *cp;
	static int start = 1;

	if (outbuf == NULL) {
		outbuf = malloc(BSIZE + HDRSIZE);
		if (outbuf == NULL)
			return (-1);
	}
	/* If we are sending less than 8 bytes, the same char will look
	 * the same if we don't pad it out with random bytes */
	if (start) {
		start = 0;
	}

	/* lets recurse if we want to send the data in small chunks */
	if (len > MAXWRITE) {
		j = 0;
		for (i = 0; i < len; i += k) {
			k = DES_enc_write(fd, &(buf[i]),
			    ((len - i) > MAXWRITE) ? MAXWRITE : (len - i),
			    sched, iv);
			if (k < 0)
				return (k);
			else
				j += k;
		}
		return (j);
	}

	/* write length first */
	p = outbuf;
	l2n(len, p);

	/* pad short strings */
	if (len < 8) {
		cp = shortbuf;
		memcpy(shortbuf, buf, len);
		arc4random_buf(shortbuf + len, 8 - len);
		rnum = 8;
	} else {
		cp = buf;
		rnum = ((len + 7)/8*8); /* round up to nearest eight */
	}

	if (DES_rw_mode & DES_PCBC_MODE)
		DES_pcbc_encrypt(cp, &(outbuf[HDRSIZE]), (len < 8) ? 8 : len,
		    sched, iv, DES_ENCRYPT);
	else
		DES_cbc_encrypt(cp, &(outbuf[HDRSIZE]), (len < 8) ? 8 : len,
		    sched, iv, DES_ENCRYPT);

	/* output */
	outnum = rnum + HDRSIZE;

	for (j = 0; j < outnum; j += i) {
		/* eay 26/08/92 I was not doing writing from where we
		 * got up to. */
		i = write(fd, (void *)&(outbuf[j]), outnum - j);
		if (i == -1) {
#ifdef EINTR
			if (errno == EINTR)
				i = 0;
			else
#endif
				/* This is really a bad error - very bad
				 * It will stuff-up both ends. */
				return (-1);
		}
	}

	return (len);
}
LCRYPTO_ALIAS(DES_enc_write);