[openssh.git] / auth-skey.c

#include "includes.h"
#ifdef SKEY
RCSID("$OpenBSD: auth-skey.c,v 1.7 2000/06/20 01:39:38 markus Exp $");

#include "ssh.h"
#include "packet.h"
#include <openssl/sha.h>

/* from %OpenBSD: skeylogin.c,v 1.32 1999/08/16 14:46:56 millert Exp % */

/*
 * try skey authentication,
 * return 1 on success, 0 on failure, -1 if skey is not available
 */

int
auth_skey_password(struct passwd * pw, const char *password)
{
	if (strncasecmp(password, "s/key", 5) == 0) {
		char *skeyinfo = skey_keyinfo(pw->pw_name);
		if (skeyinfo == NULL) {
			debug("generating fake skeyinfo for %.100s.",
			    pw->pw_name);
			skeyinfo = skey_fake_keyinfo(pw->pw_name);
		}
		if (skeyinfo != NULL)
			packet_send_debug(skeyinfo);
		/* Try again. */
		return 0;
	} else if (skey_haskey(pw->pw_name) == 0 &&
		   skey_passcheck(pw->pw_name, (char *) password) != -1) {
		/* Authentication succeeded. */
		return 1;
	}
	/* Fall back to ordinary passwd authentication. */
	return -1;
}

/* 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;
	SHA_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 */
	up = malloc(SHA_DIGEST_LENGTH);
	if (up != NULL) {
		struct stat sb;
		time_t t;
		int fd;

		SHA1_Init(&ctx);
		SHA1_Update(&ctx, username, strlen(username));
		SHA1_Final(up, &ctx);

		/* 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);
			fd = -1;
			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;
		}
		if (fd != -1)
			close(fd);
	}

	/* Put that in your pipe and smoke it */
	if (flg == 0) {
		/* Hash secret value with username */
		SHA1_Init(&ctx);
		SHA1_Update(&ctx, secret, secretlen);
		SHA1_Update(&ctx, username, strlen(username));
		SHA1_Final(up, &ctx);
		
		/* Zero out */
		memset(secret, 0, secretlen);

		/* Now hash the hash */
		SHA1_Init(&ctx);
		SHA1_Update(&ctx, up, strlen(up));
		SHA1_Final(up, &ctx);
		
		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, SHA_DIGEST_LENGTH); /* 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;
}

#endif /* SKEY */
Commit	Line	Data
5260325f	1	#include "includes.h"
91b8065d	2	#ifdef SKEY
74fc9186	3	RCSID("$OpenBSD: auth-skey.c,v 1.7 2000/06/20 01:39:38 markus Exp $");
8efc0c15	4
8efc0c15	5	#include "ssh.h"
57112b5a	6	#include "packet.h"
a4070484	7	#include <openssl/sha.h>
8efc0c15	8
	9	/* from %OpenBSD: skeylogin.c,v 1.32 1999/08/16 14:46:56 millert Exp % */
	10
6ae2364d	11	/*
57112b5a	12	* try skey authentication,
6ae2364d	13	* return 1 on success, 0 on failure, -1 if skey is not available
57112b5a	14	*/
57112b5a	15
6ae2364d	16	int
57112b5a	17	auth_skey_password(struct passwd * pw, const char *password)
	18	{
	19	if (strncasecmp(password, "s/key", 5) == 0) {
	20	char *skeyinfo = skey_keyinfo(pw->pw_name);
	21	if (skeyinfo == NULL) {
	22	debug("generating fake skeyinfo for %.100s.",
	23	pw->pw_name);
	24	skeyinfo = skey_fake_keyinfo(pw->pw_name);
	25	}
	26	if (skeyinfo != NULL)
	27	packet_send_debug(skeyinfo);
	28	/* Try again. */
	29	return 0;
	30	} else if (skey_haskey(pw->pw_name) == 0 &&
	31	skey_passcheck(pw->pw_name, (char *) password) != -1) {
	32	/* Authentication succeeded. */
	33	return 1;
	34	}
	35	/* Fall back to ordinary passwd authentication. */
	36	return -1;
	37	}
59625cbb	38
59625cbb	39	/* from %OpenBSD: skeylogin.c,v 1.32 1999/08/16 14:46:56 millert Exp % */
8efc0c15	40
	41	#define ROUND(x) (((x)[0] << 24) + (((x)[1]) << 16) + (((x)[2]) << 8) + \
	42	((x)[3]))
	43
	44	/*
	45	* hash_collapse()
	46	*/
	47	static u_int32_t
	48	hash_collapse(s)
6ae2364d	49	u_char *s;
8efc0c15	50	{
6ae2364d	51	int len, target;
8efc0c15	52	u_int32_t i;
	53
	54	if ((strlen(s) % sizeof(u_int32_t)) == 0)
6ae2364d	55	target = strlen(s); /* Multiple of 4 */
8efc0c15	56	else
8efc0c15	57	target = strlen(s) - (strlen(s) % sizeof(u_int32_t));
6ae2364d	58
8efc0c15	59	for (i = 0, len = 0; len < target; len += 4)
6ae2364d	60	i ^= ROUND(s + len);
8efc0c15	61
	62	return i;
	63	}
5260325f	64
8efc0c15	65	char *
	66	skey_fake_keyinfo(char *username)
	67	{
	68	int i;
	69	u_int ptr;
	70	u_char hseed[SKEY_MAX_SEED_LEN], flg = 1, *up;
	71	char pbuf[SKEY_MAX_PW_LEN+1];
	72	static char skeyprompt[SKEY_MAX_CHALLENGE+1];
	73	char *secret = NULL;
	74	size_t secretlen = 0;
2598df62	75	SHA_CTX ctx;
8efc0c15	76	char p, u;
	77
	78	/*
	79	* Base first 4 chars of seed on hostname.
	80	* Add some filler for short hostnames if necessary.
	81	*/
	82	if (gethostname(pbuf, sizeof(pbuf)) == -1)
	83	*(p = pbuf) = '.';
	84	else
	85	for (p = pbuf; p && isalnum(p); p++)
	86	if (isalpha(p) && isupper(p))
	87	p = tolower(p);
	88	if (*p && pbuf - p < 4)
	89	(void)strncpy(p, "asjd", 4 - (pbuf - p));
	90	pbuf[4] = '\0';
	91
	92	/* Hash the username if possible */
2598df62	93	up = malloc(SHA_DIGEST_LENGTH);
2598df62	94	if (up != NULL) {
8efc0c15	95	struct stat sb;
	96	time_t t;
	97	int fd;
	98
2598df62	99	SHA1_Init(&ctx);
2598df62	100	SHA1_Update(&ctx, username, strlen(username));
a4070484	101	SHA1_Final(up, &ctx);
2598df62	102
8efc0c15	103	/* Collapse the hash */
	104	ptr = hash_collapse(up);
	105	memset(up, 0, strlen(up));
	106
	107	/* See if the random file's there, else use ctime */
	108	if ((fd = open(_SKEY_RAND_FILE_PATH_, O_RDONLY)) != -1
	109	&& fstat(fd, &sb) == 0 &&
	110	sb.st_size > (off_t)SKEY_MAX_SEED_LEN &&
	111	lseek(fd, ptr % (sb.st_size - SKEY_MAX_SEED_LEN),
	112	SEEK_SET) != -1 && read(fd, hseed,
	113	SKEY_MAX_SEED_LEN) == SKEY_MAX_SEED_LEN) {
	114	close(fd);
a408af76	115	fd = -1;
8efc0c15	116	secret = hseed;
	117	secretlen = SKEY_MAX_SEED_LEN;
	118	flg = 0;
	119	} else if (!stat(_PATH_MEM, &sb) \|\| !stat("/", &sb)) {
	120	t = sb.st_ctime;
	121	secret = ctime(&t);
	122	secretlen = strlen(secret);
	123	flg = 0;
	124	}
a408af76	125	if (fd != -1)
a408af76	126	close(fd);
8efc0c15	127	}
	128
	129	/* Put that in your pipe and smoke it */
	130	if (flg == 0) {
	131	/* Hash secret value with username */
2598df62	132	SHA1_Init(&ctx);
	133	SHA1_Update(&ctx, secret, secretlen);
	134	SHA1_Update(&ctx, username, strlen(username));
a4070484	135	SHA1_Final(up, &ctx);
8efc0c15	136
	137	/* Zero out */
	138	memset(secret, 0, secretlen);
	139
	140	/* Now hash the hash */
2598df62	141	SHA1_Init(&ctx);
2598df62	142	SHA1_Update(&ctx, up, strlen(up));
a4070484	143	SHA1_Final(up, &ctx);
8efc0c15	144
	145	ptr = hash_collapse(up + 4);
	146
	147	for (i = 4; i < 9; i++) {
	148	pbuf[i] = (ptr % 10) + '0';
	149	ptr /= 10;
	150	}
	151	pbuf[i] = '\0';
	152
	153	/* Sequence number */
	154	ptr = ((up[2] + up[3]) % 99) + 1;
	155
2598df62	156	memset(up, 0, SHA_DIGEST_LENGTH); /* SHA1 specific */
8efc0c15	157	free(up);
	158
	159	(void)snprintf(skeyprompt, sizeof skeyprompt,
	160	"otp-%.s %d %.s",
	161	SKEY_MAX_HASHNAME_LEN,
	162	skey_get_algorithm(),
	163	ptr, SKEY_MAX_SEED_LEN,
	164	pbuf);
	165	} else {
	166	/* Base last 8 chars of seed on username */
	167	u = username;
	168	i = 8;
	169	p = &pbuf[4];
	170	do {
	171	if (*u == 0) {
	172	/* Pad remainder with zeros */
	173	while (--i >= 0)
	174	*p++ = '0';
	175	break;
	176	}
	177
	178	p++ = (u++ % 10) + '0';
	179	} while (--i != 0);
	180	pbuf[12] = '\0';
	181
	182	(void)snprintf(skeyprompt, sizeof skeyprompt,
	183	"otp-%.s %d %.s",
	184	SKEY_MAX_HASHNAME_LEN,
	185	skey_get_algorithm(),
	186	99, SKEY_MAX_SEED_LEN, pbuf);
	187	}
	188	return skeyprompt;
	189	}
91b8065d	190
5260325f	191	#endif /* SKEY */