freebsd-dev/usr.sbin/xntpd/lib/authkeys.c
1995-05-30 03:57:47 +00:00

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/*
* authkeys.c - routines to manage the storage of authentication keys
*/
#include <stdio.h>
#include "ntp_types.h"
#include "ntp_string.h"
#include "ntp_malloc.h"
#include "ntp_stdlib.h"
/*
* Structure to store keys in in the hash table.
*/
struct savekey {
struct savekey *next;
union {
#ifdef DES
U_LONG DES_key[2];
#endif
#ifdef MD5
char MD5_key[32];
#endif
} k;
u_long keyid;
u_short flags;
#ifdef MD5
int keylen;
#endif
};
#define KEY_TRUSTED 0x1 /* this key is trusted */
#define KEY_KNOWN 0x2 /* this key is known */
#ifdef DES
#define KEY_DES 0x100 /* this is a DES type key */
#endif
#ifdef MD5
#define KEY_MD5 0x200 /* this is a MD5 type key */
#endif
/*
* The hash table. This is indexed by the low order bits of the
* keyid. We make this fairly big for potentially busy servers.
*/
#define HASHSIZE 64
#define HASHMASK ((HASHSIZE)-1)
#define KEYHASH(keyid) ((keyid) & HASHMASK)
struct savekey *key_hash[HASHSIZE];
U_LONG authkeynotfound;
U_LONG authkeylookups;
U_LONG authnumkeys;
U_LONG authuncached;
U_LONG authkeyuncached;
U_LONG authnokey; /* calls to encrypt with no key */
U_LONG authencryptions;
U_LONG authdecryptions;
/*
* Storage for free key structures. We malloc() such things but
* never free them.
*/
struct savekey *authfreekeys;
int authnumfreekeys;
#define MEMINC 12 /* number of new free ones to get at once */
#ifdef DES
/*
* Size of the key schedule
*/
#define KEY_SCHED_SIZE 128 /* number of octets to store key schedule */
/*
* The zero key, which we always have. Store the permutted key
* zero in here.
*/
#define ZEROKEY_L 0x01010101 /* odd parity zero key */
#define ZEROKEY_R 0x01010101 /* right half of same */
u_char DESzeroekeys[KEY_SCHED_SIZE];
u_char DESzerodkeys[KEY_SCHED_SIZE];
u_char DEScache_ekeys[KEY_SCHED_SIZE];
u_char DEScache_dkeys[KEY_SCHED_SIZE];
#endif
/*
* The key cache. We cache the last key we looked at here.
*/
u_long cache_keyid;
u_short cache_flags;
#ifdef MD5
int cache_keylen;
char *cache_key;
#endif
/*
* init_auth - initialize internal data
*/
void
init_auth()
{
U_LONG zerokey[2];
/*
* Initialize hash table and free list
*/
memset((char *)key_hash, 0, sizeof key_hash);
cache_flags = cache_keyid = 0;
authnumfreekeys = authkeynotfound = authkeylookups = 0;
authnumkeys = authuncached = authkeyuncached = authnokey = 0;
authencryptions = authdecryptions = 0;
#ifdef DES
/*
* Initialize the zero key
*/
zerokey[0] = ZEROKEY_L;
zerokey[1] = ZEROKEY_R;
/* could just zero all */
DESauth_subkeys(zerokey, DESzeroekeys, DESzerodkeys);
#endif
}
/*
* auth_findkey - find a key in the hash table
*/
struct savekey *
auth_findkey(keyno)
u_long keyno;
{
register struct savekey *sk;
sk = key_hash[KEYHASH(keyno)];
while (sk != 0) {
if (keyno == sk->keyid)
return sk;
sk = sk->next;
}
return 0;
}
/*
* auth_havekey - return whether a key is known
*/
int
auth_havekey(keyno)
u_long keyno;
{
register struct savekey *sk;
if (keyno == 0 || (keyno == cache_keyid))
return 1;
sk = key_hash[KEYHASH(keyno)];
while (sk != 0) {
if (keyno == sk->keyid) {
if (sk->flags & KEY_KNOWN)
return 1;
else {
authkeynotfound++;
return 0;
}
}
sk = sk->next;
}
authkeynotfound++;
return 0;
}
/*
* authhavekey - return whether a key is known. Permute and cache
* the key as a side effect.
*/
int
authhavekey(keyno)
u_long keyno;
{
register struct savekey *sk;
authkeylookups++;
if (keyno == 0 || keyno == cache_keyid)
return 1;
sk = key_hash[KEYHASH(keyno)];
while (sk != 0) {
if (keyno == sk->keyid)
break;
sk = sk->next;
}
if (sk == 0 || !(sk->flags & KEY_KNOWN)) {
authkeynotfound++;
return 0;
}
cache_keyid = sk->keyid;
cache_flags = sk->flags;
#ifdef MD5
if (sk->flags & KEY_MD5) {
cache_keylen = sk->keylen;
cache_key = (char *) sk->k.MD5_key; /* XXX */
return 1;
}
#endif
#ifdef DES
if (sk->flags & KEY_DES) {
DESauth_subkeys(sk->k.DES_key, DEScache_ekeys, DEScache_dkeys);
return 1;
}
#endif
return 0;
}
/*
* auth_moremem - get some more free key structures
*/
int
auth_moremem()
{
register struct savekey *sk;
register int i;
sk = (struct savekey *)malloc(MEMINC * sizeof(struct savekey));
if (sk == 0)
return 0;
for (i = MEMINC; i > 0; i--) {
sk->next = authfreekeys;
authfreekeys = sk++;
}
authnumfreekeys += MEMINC;
return authnumfreekeys;
}
/*
* authtrust - declare a key to be trusted/untrusted
*/
void
authtrust(keyno, trust)
u_long keyno;
int trust;
{
register struct savekey *sk;
sk = key_hash[KEYHASH(keyno)];
while (sk != 0) {
if (keyno == sk->keyid)
break;
sk = sk->next;
}
if (sk == 0 && !trust)
return;
if (sk != 0) {
if (cache_keyid == keyno)
cache_flags = cache_keyid = 0;
if (trust) {
sk->flags |= KEY_TRUSTED;
return;
}
sk->flags &= ~KEY_TRUSTED;
if (!(sk->flags & KEY_KNOWN)) {
register struct savekey *skp;
skp = key_hash[KEYHASH(keyno)];
if (skp == sk) {
key_hash[KEYHASH(keyno)] = sk->next;
} else {
while (skp->next != sk)
skp = skp->next;
skp->next = sk->next;
}
authnumkeys--;
sk->next = authfreekeys;
authfreekeys = sk;
authnumfreekeys++;
}
return;
}
if (authnumfreekeys == 0)
if (auth_moremem() == 0)
return;
sk = authfreekeys;
authfreekeys = sk->next;
authnumfreekeys--;
sk->keyid = keyno;
sk->flags = KEY_TRUSTED;
sk->next = key_hash[KEYHASH(keyno)];
key_hash[KEYHASH(keyno)] = sk;
authnumkeys++;
return;
}
/*
* authistrusted - determine whether a key is trusted
*/
int
authistrusted(keyno)
u_long keyno;
{
register struct savekey *sk;
if (keyno == cache_keyid)
return ((cache_flags & KEY_TRUSTED) != 0);
authkeyuncached++;
sk = key_hash[KEYHASH(keyno)];
while (sk != 0) {
if (keyno == sk->keyid)
break;
sk = sk->next;
}
if (sk == 0 || !(sk->flags & KEY_TRUSTED))
return 0;
return 1;
}
#ifdef DES
/*
* DESauth_setkey - set a key into the key array
*/
void
DESauth_setkey(keyno, key)
u_long keyno;
const U_LONG *key;
{
register struct savekey *sk;
/*
* See if we already have the key. If so just stick in the
* new value.
*/
sk = key_hash[KEYHASH(keyno)];
while (sk != 0) {
if (keyno == sk->keyid) {
sk->k.DES_key[0] = key[0];
sk->k.DES_key[1] = key[1];
sk->flags |= KEY_KNOWN | KEY_DES;
if (cache_keyid == keyno)
cache_flags = cache_keyid = 0;
return;
}
sk = sk->next;
}
/*
* Need to allocate new structure. Do it.
*/
if (authnumfreekeys == 0) {
if (auth_moremem() == 0)
return;
}
sk = authfreekeys;
authfreekeys = sk->next;
authnumfreekeys--;
sk->k.DES_key[0] = key[0];
sk->k.DES_key[1] = key[1];
sk->keyid = keyno;
sk->flags = KEY_KNOWN | KEY_DES;
sk->next = key_hash[KEYHASH(keyno)];
key_hash[KEYHASH(keyno)] = sk;
authnumkeys++;
return;
}
#endif
#ifdef MD5
void
MD5auth_setkey(keyno, key)
u_long keyno;
const U_LONG *key;
{
register struct savekey *sk;
/*
* See if we already have the key. If so just stick in the
* new value.
*/
sk = key_hash[KEYHASH(keyno)];
while (sk != 0) {
if (keyno == sk->keyid) {
strncpy(sk->k.MD5_key, (char *)key, sizeof(sk->k.MD5_key));
if ((sk->keylen = strlen((char *)key)) >
sizeof(sk->k.MD5_key))
sk->keylen = sizeof(sk->k.MD5_key);
sk->flags |= KEY_KNOWN | KEY_MD5;
if (cache_keyid == keyno)
cache_flags = cache_keyid = 0;
return;
}
sk = sk->next;
}
/*
* Need to allocate new structure. Do it.
*/
if (authnumfreekeys == 0) {
if (auth_moremem() == 0)
return;
}
sk = authfreekeys;
authfreekeys = sk->next;
authnumfreekeys--;
strncpy(sk->k.MD5_key, (char *)key, sizeof(sk->k.MD5_key));
if ((sk->keylen = strlen((char *)key)) > sizeof(sk->k.MD5_key))
sk->keylen = sizeof(sk->k.MD5_key);
sk->keyid = keyno;
sk->flags = KEY_KNOWN | KEY_MD5;
sk->next = key_hash[KEYHASH(keyno)];
key_hash[KEYHASH(keyno)] = sk;
authnumkeys++;
return;
}
#endif
/*
* auth_delkeys - delete all known keys, in preparation for rereading
* the keys file (presumably)
*/
void
auth_delkeys()
{
register struct savekey *sk;
register struct savekey **skp;
register int i;
for (i = 0; i < HASHSIZE; i++) {
skp = &(key_hash[i]);
sk = key_hash[i];
while (sk != 0) {
sk->flags &= ~(KEY_KNOWN
#ifdef MD5
| KEY_MD5
#endif
#ifdef DES
| KEY_DES
#endif
);
if (sk->flags == 0) {
*skp = sk->next;
authnumkeys--;
sk->next = authfreekeys;
authfreekeys = sk;
authnumfreekeys++;
sk = *skp;
} else {
skp = &(sk->next);
sk = sk->next;
}
}
}
}
/*
* auth1crypt - support for two stage encryption, part 1.
*/
void
auth1crypt(keyno, pkt, length)
u_long keyno;
U_LONG *pkt;
int length; /* length of all encrypted data */
{
if (keyno && keyno != cache_keyid) {
authkeyuncached++;
if (!authhavekey(keyno)) {
authnokey++;
return;
}
}
#ifdef DES
if (!keyno || (cache_flags & KEY_DES)) {
DESauth1crypt(keyno, pkt, length);
return;
}
#endif
#ifdef MD5
if (cache_flags & KEY_MD5) {
MD5auth1crypt(keyno, pkt, length);
return;
}
#endif
}
/*
* auth1crypt - support for two stage encryption, part 1.
*/
int
auth2crypt(keyno, pkt, length)
u_long keyno;
U_LONG *pkt;
int length; /* total length of encrypted area */
{
if (keyno && keyno != cache_keyid) {
authkeyuncached++;
if (!authhavekey(keyno)) {
authnokey++;
return 0;
}
}
#ifdef DES
if (!keyno || (cache_flags & KEY_DES))
return DESauth2crypt(keyno, pkt, length);
#endif
#ifdef MD5
if (cache_flags & KEY_MD5)
return MD5auth2crypt(keyno, pkt, length);
#endif
return 0;
}
int
authencrypt(keyno, pkt, length)
u_long keyno;
U_LONG *pkt;
int length; /* length of encrypted portion of packet */
{
int sendlength = 0;
if (keyno && keyno != cache_keyid) {
authkeyuncached++;
if (!authhavekey(keyno)) {
authnokey++;
return 0;
}
}
#ifdef DES
if (!keyno || (cache_flags & KEY_DES))
return sendlength = DESauthencrypt(keyno, pkt, length);
#endif
#ifdef MD5
if (cache_flags & KEY_MD5)
return MD5authencrypt(keyno, pkt, length);
#endif
return 0;
}
int
authdecrypt(keyno, pkt, length)
u_long keyno;
U_LONG *pkt;
int length; /* length of variable data in octets */
{
if (keyno && (keyno != cache_keyid)) {
authkeyuncached++;
if (!authhavekey(keyno)) {
authnokey++;
return 0;
}
}
#ifdef DES
if (!keyno || (cache_flags & KEY_DES))
return DESauthdecrypt(keyno, pkt, length);
#endif
#ifdef MD5
if (cache_flags & KEY_MD5)
return MD5authdecrypt(keyno, pkt, length);
#endif
return 0;
}