130 lines
2.5 KiB
C
130 lines
2.5 KiB
C
#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include <fcntl.h>
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#include <termios.h>
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#include <signal.h>
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#include "skey.h"
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#include "mdx.h"
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/* Crunch a key:
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* concatenate the seed and the password, run through MDX and
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* collapse to 64 bits. This is defined as the user's starting key.
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*/
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int
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keycrunch(result,seed,passwd)
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char *result; /* 8-byte result */
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char *seed; /* Seed, any length */
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char *passwd; /* Password, any length */
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{
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char *buf;
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MDX_CTX md;
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u_long results[4];
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unsigned int buflen;
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buflen = strlen(seed) + strlen(passwd);
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if((buf = malloc(buflen+1)) == NULL)
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return -1;
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strcpy(buf,seed);
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strcat(buf,passwd);
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/* Crunch the key through MD[45] */
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sevenbit(buf);
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MDXInit(&md);
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MDXUpdate(&md,(unsigned char *)buf,buflen);
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MDXFinal((unsigned char *)results,&md);
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free(buf);
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results[0] ^= results[2];
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results[1] ^= results[3];
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memcpy(result,(char *)results,8);
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return 0;
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}
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/* The one-way function f(). Takes 8 bytes and returns 8 bytes in place */
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void
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f(x)
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char *x;
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{
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MDX_CTX md;
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u_long results[4];
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MDXInit(&md);
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MDXUpdate(&md,(unsigned char *)x,8);
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MDXFinal((unsigned char *)results,&md);
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/* Fold 128 to 64 bits */
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results[0] ^= results[2];
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results[1] ^= results[3];
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memcpy(x,(char *)results,8);
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}
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/* Strip trailing cr/lf from a line of text */
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void
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rip(buf)
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char *buf;
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{
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buf[strcspn(buf, "\r\n")] = 0;
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}
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static struct termios saved_ttymode;
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static void interrupt(sig)
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int sig;
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{
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tcsetattr(0, TCSANOW, &saved_ttymode);
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exit(1);
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}
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char *
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readpass(buf,n)
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char *buf;
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int n;
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{
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struct termios noecho_ttymode;
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void (*oldsig)();
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/* Save normal line editing modes */
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tcgetattr(0, &saved_ttymode);
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if ((oldsig = signal(SIGINT, SIG_IGN)) != SIG_IGN)
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signal(SIGINT, interrupt);
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/* Turn off echoing */
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tcgetattr(0, &noecho_ttymode);
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noecho_ttymode.c_lflag &= ~ECHO;
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tcsetattr(0, TCSANOW, &noecho_ttymode);
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fgets(buf,n,stdin);
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rip(buf);
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/* Restore previous tty modes */
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tcsetattr(0, TCSANOW, &saved_ttymode);
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if (oldsig != SIG_IGN)
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signal(SIGINT, oldsig);
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/*
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after the secret key is taken from the keyboard, the line feed is
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written to standard error instead of standard output. That means that
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anyone using the program from a terminal won't notice, but capturing
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standard output will get the key words without a newline in front of
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them.
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*/
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fprintf(stderr, "\n");
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fflush(stderr);
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sevenbit(buf);
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return buf;
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}
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sevenbit(s)
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char *s;
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{
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/* make sure there are only 7 bit code in the line*/
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while(*s){
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*s &= 0x7f;
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s++;
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}
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}
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