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#include "includes.h"
RCSID("$Id: auth-skey.c,v 1.2 1999/10/16 20:57:52 deraadt Exp $");
#include "ssh.h"
#include <sha1.h>
/* from %OpenBSD: skeylogin.c,v 1.32 1999/08/16 14:46:56 millert Exp % */
#define ROUND(x) (((x)[0] << 24) + (((x)[1]) << 16) + (((x)[2]) << 8) + \
((x)[3]))
/*
* hash_collapse()
*/
static u_int32_t
hash_collapse(s)
u_char *s;
{
int len, target;
u_int32_t i;
if ((strlen(s) % sizeof(u_int32_t)) == 0)
target = strlen(s); /* Multiple of 4 */
else
target = strlen(s) - (strlen(s) % sizeof(u_int32_t));
for (i = 0, len = 0; len < target; len += 4)
i ^= ROUND(s + len);
return i;
}
char *
skey_fake_keyinfo(char *username)
{
int i;
u_int ptr;
u_char hseed[SKEY_MAX_SEED_LEN], flg = 1, *up;
char pbuf[SKEY_MAX_PW_LEN+1];
static char skeyprompt[SKEY_MAX_CHALLENGE+1];
char *secret = NULL;
size_t secretlen = 0;
SHA1_CTX ctx;
char *p, *u;
/*
* Base first 4 chars of seed on hostname.
* Add some filler for short hostnames if necessary.
*/
if (gethostname(pbuf, sizeof(pbuf)) == -1)
*(p = pbuf) = '.';
else
for (p = pbuf; *p && isalnum(*p); p++)
if (isalpha(*p) && isupper(*p))
*p = tolower(*p);
if (*p && pbuf - p < 4)
(void)strncpy(p, "asjd", 4 - (pbuf - p));
pbuf[4] = '\0';
/* Hash the username if possible */
if ((up = SHA1Data(username, strlen(username), NULL)) != NULL) {
struct stat sb;
time_t t;
int fd;
/* Collapse the hash */
ptr = hash_collapse(up);
memset(up, 0, strlen(up));
/* See if the random file's there, else use ctime */
if ((fd = open(_SKEY_RAND_FILE_PATH_, O_RDONLY)) != -1
&& fstat(fd, &sb) == 0 &&
sb.st_size > (off_t)SKEY_MAX_SEED_LEN &&
lseek(fd, ptr % (sb.st_size - SKEY_MAX_SEED_LEN),
SEEK_SET) != -1 && read(fd, hseed,
SKEY_MAX_SEED_LEN) == SKEY_MAX_SEED_LEN) {
close(fd);
secret = hseed;
secretlen = SKEY_MAX_SEED_LEN;
flg = 0;
} else if (!stat(_PATH_MEM, &sb) || !stat("/", &sb)) {
t = sb.st_ctime;
secret = ctime(&t);
secretlen = strlen(secret);
flg = 0;
}
}
/* Put that in your pipe and smoke it */
if (flg == 0) {
/* Hash secret value with username */
SHA1Init(&ctx);
SHA1Update(&ctx, secret, secretlen);
SHA1Update(&ctx, username, strlen(username));
SHA1End(&ctx, up);
/* Zero out */
memset(secret, 0, secretlen);
/* Now hash the hash */
SHA1Init(&ctx);
SHA1Update(&ctx, up, strlen(up));
SHA1End(&ctx, up);
ptr = hash_collapse(up + 4);
for (i = 4; i < 9; i++) {
pbuf[i] = (ptr % 10) + '0';
ptr /= 10;
}
pbuf[i] = '\0';
/* Sequence number */
ptr = ((up[2] + up[3]) % 99) + 1;
memset(up, 0, 20); /* SHA1 specific */
free(up);
(void)snprintf(skeyprompt, sizeof skeyprompt,
"otp-%.*s %d %.*s",
SKEY_MAX_HASHNAME_LEN,
skey_get_algorithm(),
ptr, SKEY_MAX_SEED_LEN,
pbuf);
} else {
/* Base last 8 chars of seed on username */
u = username;
i = 8;
p = &pbuf[4];
do {
if (*u == 0) {
/* Pad remainder with zeros */
while (--i >= 0)
*p++ = '0';
break;
}
*p++ = (*u++ % 10) + '0';
} while (--i != 0);
pbuf[12] = '\0';
(void)snprintf(skeyprompt, sizeof skeyprompt,
"otp-%.*s %d %.*s",
SKEY_MAX_HASHNAME_LEN,
skey_get_algorithm(),
99, SKEY_MAX_SEED_LEN, pbuf);
}
return skeyprompt;
}
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