517 lines
11 KiB
C
517 lines
11 KiB
C
/* $NetBSD: skeysubr.c,v 1.28 2012/03/22 22:59:43 joerg Exp $ */
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/* S/KEY v1.1b (skeysubr.c)
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*
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* Authors:
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* Neil M. Haller <nmh@thumper.bellcore.com>
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* Philip R. Karn <karn@chicago.qualcomm.com>
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* John S. Walden <jsw@thumper.bellcore.com>
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*
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* Modifications:
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* Scott Chasin <chasin@crimelab.com>
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* Todd C. Miller <Todd.Miller@courtesan.com>
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*
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* S/KEY misc routines.
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*/
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#include <sys/cdefs.h>
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__RCSID("$NetBSD: skeysubr.c,v 1.28 2012/03/22 22:59:43 joerg Exp $");
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#include <ctype.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include <signal.h>
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#include <termios.h>
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#include <md4.h>
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#include <md5.h>
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#include <sys/rmd160.h>
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#include <sha1.h>
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#include "skey.h"
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/* Default hash function to use (index into skey_hash_types array) */
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#ifndef SKEY_HASH_DEFAULT
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#define SKEY_HASH_DEFAULT 0 /* MD4 */
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#endif
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static void f_md4(char *);
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static void f_md5(char *);
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static void f_sha1(char *);
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/* static void f_rmd160(char *x); */
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static int keycrunch_md4(char *, const char *, const char *);
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static int keycrunch_md5(char *, const char *, const char *);
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static int keycrunch_sha1(char *, const char *, const char *);
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/* static int keycrunch_rmd160(char *, const char *, const char *); */
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static void lowcase(char *);
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static void skey_echo(int);
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static void trapped(int) __dead;
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static char *mkSeedPassword(const char *, const char *, size_t *);
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/* Current hash type (index into skey_hash_types array) */
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static int skey_hash_type = SKEY_HASH_DEFAULT;
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/*
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* Hash types we support.
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* Each has an associated keycrunch() and f() function.
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*/
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struct skey_algorithm_table {
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const char *name;
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int (*keycrunch)(char *, const char *, const char *);
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void (*f)(char *);
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};
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static struct skey_algorithm_table skey_algorithm_table[] = {
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{ "md4", keycrunch_md4, f_md4 },
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{ "md5", keycrunch_md5, f_md5 },
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{ "sha1", keycrunch_sha1, f_sha1 },
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#if 0
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{ "rmd160", keycrunch_rmd160, f_rmd160 },
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#endif
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{ NULL, NULL, NULL }
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};
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/*
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* Crunch a key:
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* concatenate the (lower cased) seed and the password, run through
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* the hash algorithm and collapse to 64 bits.
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* This is defined as the user's starting key.
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*/
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int keycrunch(char *result, /* SKEY_BINKEY_SIZE result */
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const char *seed, /* Seed, any length */
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const char *passwd) /* Password, any length */
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{
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return(skey_algorithm_table[skey_hash_type].keycrunch(result, seed, passwd));
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}
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static char *mkSeedPassword(const char *seed, const char *passwd,
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size_t *buflen)
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{
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char *buf;
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*buflen = strlen(seed) + strlen(passwd);
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if ((buf = (char *) malloc(*buflen + 1)) == NULL)
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return NULL;
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strcpy(buf, seed);
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lowcase(buf);
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strcat(buf, passwd);
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sevenbit(buf);
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return buf;
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}
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static int keycrunch_md4(char *result, /* SKEY_BINKEY_SIZE result */
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const char *seed, /* Seed, any length */
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const char *passwd) /* Password, any length */
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{
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char *buf;
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MD4_CTX md;
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size_t buflen;
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u_int32_t results[4];
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if ((buf = mkSeedPassword(seed, passwd, &buflen)) == NULL)
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return -1;
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/* Crunch the key through MD4 */
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MD4Init(&md);
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MD4Update(&md, (unsigned char *) buf, buflen);
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MD4Final((unsigned char *) (void *) results, &md);
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free(buf);
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/* Fold result from 128 to 64 bits */
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results[0] ^= results[2];
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results[1] ^= results[3];
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(void)memcpy(result, results, SKEY_BINKEY_SIZE);
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return 0;
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}
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static int keycrunch_md5(char *result, /* SKEY_BINKEY_SIZE result */
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const char *seed, /* Seed, any length */
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const char *passwd) /* Password, any length */
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{
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char *buf;
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MD5_CTX md;
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u_int32_t results[4];
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size_t buflen;
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if ((buf = mkSeedPassword(seed, passwd, &buflen)) == NULL)
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return -1;
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/* Crunch the key through MD5 */
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MD5Init(&md);
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MD5Update(&md, (unsigned char *)buf, buflen);
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MD5Final((unsigned char *) (void *)results, &md);
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free(buf);
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/* Fold result from 128 to 64 bits */
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results[0] ^= results[2];
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results[1] ^= results[3];
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(void)memcpy((void *)result, (void *)results, SKEY_BINKEY_SIZE);
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return(0);
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}
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static int keycrunch_sha1(char *result, /* SKEY_BINKEY_SIZE result */
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const char *seed, /* Seed, any length */
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const char *passwd) /* Password, any length */
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{
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char *buf;
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SHA1_CTX sha;
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size_t buflen;
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int i, j;
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if ((buf = mkSeedPassword(seed, passwd, &buflen)) == NULL)
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return -1;
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/* Crunch the key through SHA1 */
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SHA1Init(&sha);
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SHA1Update(&sha, (unsigned char *)buf, buflen);
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SHA1Final(NULL, &sha);
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free(buf);
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/* Fold 160 to 64 bits */
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sha.state[0] ^= sha.state[2];
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sha.state[1] ^= sha.state[3];
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sha.state[0] ^= sha.state[4];
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/*
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* SHA1 is a big endian algorithm but RFC2289 mandates that
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* the result be in little endian form, so we copy to the
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* result buffer manually.
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*/
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for(i=j=0; j<8; i++, j+=4) {
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result[j] = (unsigned char)(sha.state[i] & 0xff);
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result[j+1] = (unsigned char)((sha.state[i] >> 8) & 0xff);
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result[j+2] = (unsigned char)((sha.state[i] >> 16) & 0xff);
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result[j+3] = (unsigned char)((sha.state[i] >> 24) & 0xff);
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}
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return(0);
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}
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#if 0
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static int keycrunch_rmd160(char *result, /* SKEY_BINKEY_SIZE result */
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const char *seed, /* Seed, any length */
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const char *passwd) /* Password, any length */
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{
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char *buf;
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RMD160_CTX rmd;
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u_int32_t results[5];
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size_t buflen;
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if ((buf = mkSeedPassword(seed, passwd, &buflen)) == NULL)
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return -1;
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/* Crunch the key through RMD-160 */
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RMD160Init(&rmd);
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RMD160Update(&rmd, (unsigned char *)buf, buflen);
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RMD160Final((unsigned char *)(void *)results, &rmd);
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free(buf);
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/* Fold 160 to 64 bits */
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results[0] ^= results[2];
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results[1] ^= results[3];
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results[0] ^= results[4];
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(void)memcpy((void *)result, (void *)results, SKEY_BINKEY_SIZE);
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return(0);
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}
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#endif
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/* The one-way function f(). Takes 8 bytes and returns 8 bytes in place */
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void f(char *x)
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{
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skey_algorithm_table[skey_hash_type].f(x);
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}
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static void f_md4(char *x)
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{
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MD4_CTX md;
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u_int32_t results[4];
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MD4Init(&md);
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MD4Update(&md, (unsigned char *) x, SKEY_BINKEY_SIZE);
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MD4Final((unsigned char *) (void *) 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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(void)memcpy(x, results, SKEY_BINKEY_SIZE);
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}
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static void f_md5(char *x)
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{
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MD5_CTX md;
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u_int32_t results[4];
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MD5Init(&md);
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MD5Update(&md, (unsigned char *)x, SKEY_BINKEY_SIZE);
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MD5Final((unsigned char *) (void *)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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(void)memcpy((void *)x, (void *)results, SKEY_BINKEY_SIZE);
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}
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static void f_sha1(char *x)
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{
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SHA1_CTX sha;
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int i, j;
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SHA1Init(&sha);
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SHA1Update(&sha, (unsigned char *)x, SKEY_BINKEY_SIZE);
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SHA1Final(NULL, &sha);
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/* Fold 160 to 64 bits */
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sha.state[0] ^= sha.state[2];
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sha.state[1] ^= sha.state[3];
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sha.state[0] ^= sha.state[4];
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for(i=j=0; j<8; i++, j+=4) {
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x[j] = (unsigned char)(sha.state[i] & 0xff);
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x[j+1] = (unsigned char)((sha.state[i] >> 8) & 0xff);
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x[j+2] = (unsigned char)((sha.state[i] >> 16) & 0xff);
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x[j+3] = (unsigned char)((sha.state[i] >> 24) & 0xff);
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}
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}
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#if 0
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static void f_rmd160(char *x)
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{
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RMD160_CTX rmd;
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u_int32_t results[5];
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RMD160Init(&rmd);
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RMD160Update(&rmd, (unsigned char *)x, SKEY_BINKEY_SIZE);
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RMD160Final((unsigned char *)(void *)results, &rmd);
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/* Fold 160 to 64 bits */
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results[0] ^= results[2];
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results[1] ^= results[3];
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results[0] ^= results[4];
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(void)memcpy((void *)x, (void *)results, SKEY_BINKEY_SIZE);
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}
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#endif
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/* Strip trailing cr/lf from a line of text */
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void rip(char *buf)
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{
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buf += strcspn(buf, "\r\n");
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if (*buf)
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*buf = '\0';
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}
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/* Read in secret password (turns off echo) */
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char *readpass(char *buf, int n)
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{
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void *old_handler;
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/* Turn off echoing */
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skey_echo(0);
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/* Catch SIGINT and save old signal handler */
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old_handler = signal(SIGINT, trapped);
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fgets(buf, n, stdin);
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rip(buf);
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putc('\n', stderr);
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fflush(stderr);
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/* Restore signal handler and turn echo back on */
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if (old_handler != SIG_ERR)
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(void)signal(SIGINT, old_handler);
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skey_echo(1);
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sevenbit(buf);
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return buf;
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}
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/* Read in an s/key OTP (does not turn off echo) */
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char *readskey(char *buf, int n)
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{
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fgets(buf, n, stdin);
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rip(buf);
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sevenbit (buf);
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return buf;
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}
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/* Signal handler for trapping ^C */
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/*ARGSUSED*/
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static void trapped(int sig)
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{
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fputs("^C\n", stderr);
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fflush(stderr);
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/* Turn on echo if necessary */
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skey_echo(1);
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exit(1);
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}
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/*
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* Convert 8-byte hex-ascii string to binary array
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* Returns 0 on success, -1 on error
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*/
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int atob8(char *out, const char *in)
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{
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int i;
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int val;
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if (in == NULL || out == NULL)
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return -1;
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for (i=0; i<8; i++) {
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if ((in = skipspace(in)) == NULL)
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return -1;
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if ((val = htoi(*in++)) == -1)
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return -1;
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*out = val << 4;
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if ((in = skipspace(in)) == NULL)
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return -1;
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if ((val = htoi(*in++)) == -1)
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return -1;
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*out++ |= val;
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}
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return 0;
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}
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/* Convert 8-byte binary array to hex-ascii string */
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int btoa8(char *out, const char *in)
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{
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int i;
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if (in == NULL || out == NULL)
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return -1;
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for (i=0;i<8;i++) {
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sprintf(out, "%02x", *in++ & 0xff);
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out += 2;
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}
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return 0;
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}
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/* Convert hex digit to binary integer */
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int htoi(int c)
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{
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if ('0' <= c && c <= '9')
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return c - '0';
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if ('a' <= c && c <= 'f')
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return 10 + c - 'a';
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if ('A' <= c && c <= 'F')
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return 10 + c - 'A';
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return -1;
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}
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/* Skip leading spaces from the string */
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const char *skipspace(const char *cp)
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{
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while (*cp == ' ' || *cp == '\t')
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cp++;
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if (*cp == '\0')
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return NULL;
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else
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return cp;
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}
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/* Remove backspaced over charaters from the string */
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void backspace(char *buf)
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{
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char bs = 0x8;
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char *cp = buf;
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char *out = buf;
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while (*cp) {
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if (*cp == bs) {
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if (out == buf) {
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cp++;
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continue;
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} else {
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cp++;
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out--;
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}
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} else {
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*out++ = *cp++;
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}
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}
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*out = '\0';
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}
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/* Make sure line is all seven bits */
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void sevenbit(char *s)
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{
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while (*s)
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*s++ &= 0x7f;
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}
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/* Set hash algorithm type */
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const char *skey_set_algorithm(const char *new)
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{
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int i;
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for (i = 0; skey_algorithm_table[i].name; i++) {
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if (strcmp(new, skey_algorithm_table[i].name) == 0) {
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skey_hash_type = i;
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return(new);
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}
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}
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return(NULL);
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}
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/* Get current hash type */
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const char *skey_get_algorithm(void)
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{
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return(skey_algorithm_table[skey_hash_type].name);
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}
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/* Turn echo on/off */
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static void skey_echo(int action)
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{
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static struct termios term;
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static int echo = 0;
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if (action == 0) {
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/* Turn echo off */
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(void) tcgetattr(fileno(stdin), &term);
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if ((echo = (term.c_lflag & ECHO)) != 0) {
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term.c_lflag &= ~ECHO;
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(void) tcsetattr(fileno(stdin), TCSAFLUSH|TCSASOFT, &term);
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}
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} else if (action && echo) {
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/* Turn echo on */
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term.c_lflag |= ECHO;
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(void) tcsetattr(fileno(stdin), TCSAFLUSH|TCSASOFT, &term);
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echo = 0;
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}
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}
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/* Convert string to lower case */
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static void lowcase(char *s)
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{
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u_char *p;
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for (p = (u_char *) s; *p; p++)
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if (isupper(*p))
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*p = tolower(*p);
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}
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