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/*
* Unix crypt(1)-style interface.
* Written by T.E.Dickey for vile (March 1999).
*
* $Header: /usr/build/vile/vile/RCS/ucrypt.c,v 1.15 2001/02/14 01:39:50 tom Exp $
*
*/
# include "estruct.h"
# include "edef.h"
#if OPT_ENCRYPT
#define MASKED(n) ((n)&(N_chars-1))
#define LEN_CLEAR 8
#define LEN_CRYPT 13
static unsigned index_1;
static unsigned index_2;
static char table1[N_chars];
static char table2[N_chars];
static char table3[N_chars];
/*
* Get the string to use as an encryption string.
*/
static int
get_encryption_key( /* make encryption key */
char *key, /* where to write key */
UINT len)
{
int status; /* return status */
int save_vl_echo = vl_echo;
char temp[NKEYLEN];
/* turn command input echo off */
vl_echo = FALSE;
temp[0] = EOS;
status = mlreply("-Encryption String: ", temp, len-1);
vl_echo = save_vl_echo;
if (status == TRUE)
vl_make_encrypt_key(key, temp);
mlerase();
return(status);
}
void
vl_encrypt_blok(char *buf, UINT len)
{
unsigned c1, c2;
for (c2 = 0; c2 < len; c2++) {
c1 = buf[c2];
buf[c2] = table2[
MASKED(table3[
MASKED(table1[
MASKED(c1+index_1)] + index_2)
] - index_2)
] - index_1;
if (++index_1 >= N_chars) {
index_1 = 0;
if(++index_2 >= N_chars)
index_2 = 0;
}
}
}
int
vl_encrypt_char(int ch)
{
char buffer[2];
buffer[0] = (char) ch;
vl_encrypt_blok(buffer, 1);
return buffer[0];
}
/*
* Calls to 'crypt()' are slow; do this only after we have gotten a new
* key from the user.
*/
void
vl_make_encrypt_key (char *dst, const char *src)
{
char key[LEN_CLEAR];
char salt[2];
memcpy(key, src, sizeof(key));
memcpy(salt, src, sizeof(salt));
memcpy(dst, (char *)crypt(key, salt), LEN_CRYPT);
dst[LEN_CRYPT] = 0;
TRACE(("made encryption key(%s)\n", dst));
}
int
vl_resetkey( /* set the buffer's encryption key if needed */
BUFFER *bp,
const char *fname)
{
register int s; /* temporary return value */
/* flag the buffer as not having encryption */
ffdocrypt(FALSE);
/* if we want to encrypt */
if (b_val(bp, MDCRYPT)) {
char temp[NFILEN];
/* don't automatically inherit key from other buffers */
if (bp->b_cryptkey[0] != EOS
&& !b_is_argument(bp)
&& strcmp(lengthen_path(strcpy(temp, fname)), bp->b_fname)) {
char prompt[80];
(void)lsprintf(prompt, "Use crypt-key from %s", bp->b_bname);
s = mlyesno(prompt);
if (s != TRUE)
return (s == FALSE);
}
/* make a key if we don't have one */
if (bp->b_cryptkey[0] == EOS) {
s = get_encryption_key(bp->b_cryptkey, sizeof(bp->b_cryptkey));
if (s != TRUE)
return (s == FALSE);
}
ffdocrypt(TRUE);
vl_setup_encrypt(bp->b_cryptkey);
}
return TRUE;
}
/* change current buffer's encryption key */
/* ARGSUSED */
int
vl_setkey(
int f GCC_UNUSED,
int n GCC_UNUSED)
{
char result[NKEYLEN];
int rc = get_encryption_key(result, sizeof(result));
if (rc == TRUE) {
TRACE(("set key for %s\n", curbp->b_bname));
(void)strcpy(curbp->b_cryptkey, result);
make_local_b_val(curbp, MDCRYPT);
set_b_val(curbp, MDCRYPT, TRUE);
curwp->w_flag |= WFMODE;
} else if (rc == FALSE) {
if (curbp->b_cryptkey[0] != EOS) {
rc = mlyesno("Discard encryption key");
if (rc == TRUE) {
TRACE(("reset key for %s\n", curbp->b_bname));
curbp->b_cryptkey[0] = EOS;
if (global_b_val(MDCRYPT)) {
make_local_b_val(curbp, MDCRYPT);
set_b_val(curbp, MDCRYPT, FALSE);
curwp->w_flag |= WFMODE;
} else if (b_val(curbp,MDCRYPT)) {
make_global_val(curbp->b_values.bv, global_b_values.bv, MDCRYPT);
curwp->w_flag |= WFMODE;
}
}
}
}
return (rc);
}
/*
* Call this function at the beginning of encrypting/decrypting a file, i.e.,
* while writing or reading it.
*/
void
vl_setup_encrypt(char *encrypted_password)
{
int j, c1, c2, temp;
unsigned mixs;
long myseed = seed; /* this isn't a random number, it's a parameter */
TRACE(("setup_encrypt(%s)\n", encrypted_password));
for (j = 0; j < LEN_CRYPT; j++)
myseed = myseed * encrypted_password[j] + j;
for (j = 0; j < N_chars; j++)
table1[j] = (char) j;
memset(table3, 0, sizeof(table3));
for (j = 0; j < N_chars; j++) {
myseed = 5 * myseed + encrypted_password[j % LEN_CRYPT];
mixs = myseed % 65521;
c2 = N_chars-1 - j;
c1 = MASKED(mixs) % (c2+1);
mixs >>= 8;
temp = table1[c2];
table1[c2] = table1[c1];
table1[c1] = temp;
if (table3[c2] == 0) {
c1 = MASKED(mixs) % c2;
while (table3[c1] != 0)
c1 = (c1+1) % c2;
table3[c2] = c1;
table3[c1] = c2;
}
}
for(j = 0; j < N_chars; j++)
table2[MASKED(table1[j])] = j;
index_1 = 0;
index_2 = 0;
}
#endif
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