Momentum-Apps/helpers/flipbip_string.c

/*
 * Copyright (c) 1988 Regents of the University of California.
 * All rights reserved.
 *
 * 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 above 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. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``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 REGENTS 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.
 */
#include "flipbip_string.h"
#include <ctype.h>
#include <stdint.h>
#include <string.h>

#include "../crypto/memzero.h"
#include "../crypto/rc4.h"

char *
flipbip_strtok(char *s, const char *delim)
{
	static char *last;
	return flipbip_strtok_r(s, delim, &last);
}
char *
flipbip_strtok_r(char *s, const char *delim, char **last)
{
	char *spanp;
	int c, sc;
	char *tok;
	if (s == NULL && (s = *last) == NULL)
		return (NULL);
	/*
	 * Skip (span) leading delimiters (s += strspn(s, delim), sort of).
	 */
cont:
	c = *s++;
	for (spanp = (char *)delim; (sc = *spanp++) != 0;) {
		if (c == sc)
			goto cont;
	}
	if (c == 0) {		/* no non-delimiter characters */
		*last = NULL;
		return (NULL);
	}
	tok = s - 1;
	/*
	 * Scan token (scan for delimiters: s += strcspn(s, delim), sort of).
	 * Note that delim must have one NUL; we stop if we see that, too.
	 */
	for (;;) {
		c = *s++;
		spanp = (char *)delim;
		do {
			if ((sc = *spanp++) == c) {
				if (c == 0)
					s = NULL;
				else
					s[-1] = 0;
				*last = s;
				return (tok);
			}
		} while (sc != 0);
	}
	/* NOTREACHED */
}

void 
flipbip_btox(const unsigned char in, char *str)
{
    unsigned char n;
    unsigned char i = in;
 
    str += 2;
    *str = '\0';
 
    for (n = 2; n != 0; --n) {
        *--str = "0123456789abcdef"[i & 0x0F];
        i >>= 4;
    }
}
void 
flipbip_xtob(const char *str, unsigned char *out, int out_len) 
{
    int len = strlen(str) / 2;
    if (len > out_len) len = out_len;
    for (int i = 0; i < len; i++) {
        char c = 0;
        if (str[i * 2] >= '0' && str[i * 2] <= '9') 
            c += (str[i * 2] - '0') << 4;
        if ((str[i * 2] & ~0x20) >= 'A' && (str[i * 2] & ~0x20) <= 'F')
            c += (10 + (str[i * 2] & ~0x20) - 'A') << 4;
        if (str[i * 2 + 1] >= '0' && str[i * 2 + 1] <= '9')
            c += (str[i * 2 + 1] - '0');
        if ((str[i * 2 + 1] & ~0x20) >= 'A' && (str[i * 2 + 1] & ~0x20) <= 'F')
            c += (10 + (str[i * 2 + 1] & ~0x20) - 'A');
        out[i] = c;
    }
}

void 
flipbip_cipher(const unsigned char* key_in, const unsigned int key_len, const char* in, char* out, const unsigned int io_len)
{
    if (io_len > 512) return;

    RC4_CTX ctx;
    uint8_t buf[256];
    memzero(buf, 256);
    
    flipbip_xtob(in, buf, io_len / 2);

    rc4_init(&ctx, key_in, key_len);
    rc4_encrypt(&ctx, buf, 256);

    for (size_t i = 0; i < (io_len / 2); i++) {
        flipbip_btox(buf[i], out + i * 2);
    }

    memzero(buf, 256);
}