577 lines
10 KiB
C
577 lines
10 KiB
C
/* $NetBSD: authkeys.c,v 1.1.1.2 2000/04/22 14:52:55 simonb Exp $ */
|
|
|
|
/*
|
|
* authkeys.c - routines to manage the storage of authentication keys
|
|
*/
|
|
|
|
#ifdef HAVE_CONFIG_H
|
|
# include <config.h>
|
|
#endif
|
|
|
|
#include <stdio.h>
|
|
|
|
#include "ntp_types.h"
|
|
#include "ntp_fp.h"
|
|
#include "ntp.h"
|
|
#include "ntpd.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 {
|
|
long bogon; /* Make sure nonempty */
|
|
#ifdef DES
|
|
u_int32 DES_key[2]; /* DES key */
|
|
#endif
|
|
#ifdef MD5
|
|
u_char MD5_key[32]; /* MD5 key */
|
|
#endif
|
|
} k;
|
|
keyid_t keyid; /* key identifier */
|
|
u_short flags; /* flags that wave */
|
|
u_long lifetime; /* remaining lifetime */
|
|
#ifdef MD5
|
|
int keylen; /* key length */
|
|
#endif
|
|
};
|
|
|
|
#define KEY_TRUSTED 0x001 /* this key is trusted */
|
|
#define KEY_DES 0x100 /* this is a DES type key */
|
|
#define KEY_MD5 0x200 /* this is a MD5 type key */
|
|
|
|
/*
|
|
* 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; /* keys not found */
|
|
u_long authkeylookups; /* calls to lookup keys */
|
|
u_long authnumkeys; /* number of active keys */
|
|
u_long authkeyexpired; /* key lifetime expirations */
|
|
u_long authkeyuncached; /* cache misses */
|
|
u_long authnokey; /* calls to encrypt with no key */
|
|
u_long authencryptions; /* calls to encrypt */
|
|
u_long authdecryptions; /* calls to decrypt */
|
|
|
|
/*
|
|
* 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 */
|
|
|
|
/*
|
|
* The key cache. We cache the last key we looked at here.
|
|
*/
|
|
keyid_t cache_keyid; /* key identifier */
|
|
u_char *cache_key; /* key pointer */
|
|
u_int cache_keylen; /* key length */
|
|
u_short cache_flags; /* flags that wave */
|
|
|
|
|
|
/*
|
|
* init_auth - initialize internal data
|
|
*/
|
|
void
|
|
init_auth(void)
|
|
{
|
|
/*
|
|
* Initialize hash table and free list
|
|
*/
|
|
memset((char *)key_hash, 0, sizeof key_hash);
|
|
}
|
|
|
|
|
|
/*
|
|
* auth_findkey - find a key in the hash table
|
|
*/
|
|
struct savekey *
|
|
auth_findkey(
|
|
keyid_t keyno
|
|
)
|
|
{
|
|
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 one if the key is known
|
|
*/
|
|
int
|
|
auth_havekey(
|
|
keyid_t keyno
|
|
)
|
|
{
|
|
struct savekey *sk;
|
|
|
|
if (keyno == 0 || (keyno == cache_keyid))
|
|
return (1);
|
|
|
|
sk = key_hash[KEYHASH(keyno)];
|
|
while (sk != 0) {
|
|
if (keyno == sk->keyid)
|
|
return (1);
|
|
|
|
sk = sk->next;
|
|
}
|
|
return (0);
|
|
}
|
|
|
|
|
|
/*
|
|
* authhavekey - return one and cache the key, if known and trusted.
|
|
*/
|
|
int
|
|
authhavekey(
|
|
keyid_t keyno
|
|
)
|
|
{
|
|
struct savekey *sk;
|
|
|
|
authkeylookups++;
|
|
if (keyno == 0 || keyno == cache_keyid)
|
|
return (1);
|
|
|
|
authkeyuncached++;
|
|
sk = key_hash[KEYHASH(keyno)];
|
|
while (sk != 0) {
|
|
if (keyno == sk->keyid)
|
|
break;
|
|
sk = sk->next;
|
|
}
|
|
if (sk == 0) {
|
|
authkeynotfound++;
|
|
return (0);
|
|
} else if (!(sk->flags & KEY_TRUSTED)) {
|
|
authnokey++;
|
|
return (0);
|
|
}
|
|
cache_keyid = sk->keyid;
|
|
cache_flags = sk->flags;
|
|
#ifdef MD5
|
|
if (sk->flags & KEY_MD5) {
|
|
cache_key = sk->k.MD5_key;
|
|
cache_keylen = sk->keylen;
|
|
return (1);
|
|
}
|
|
#endif
|
|
#ifdef DES
|
|
if (sk->flags & KEY_DES) {
|
|
cache_key = (u_char *)sk->k.DES_key;
|
|
return (1);
|
|
}
|
|
#endif
|
|
return (0);
|
|
}
|
|
|
|
|
|
/*
|
|
* auth_moremem - get some more free key structures
|
|
*/
|
|
int
|
|
auth_moremem(void)
|
|
{
|
|
struct savekey *sk;
|
|
int i;
|
|
|
|
sk = (struct savekey *)calloc(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(
|
|
keyid_t keyno,
|
|
u_long trust
|
|
)
|
|
{
|
|
struct savekey *sk;
|
|
|
|
#ifdef DEBUG
|
|
if (debug > 2)
|
|
printf("authtrust: keyid %08x life %lu\n", keyno, trust);
|
|
#endif
|
|
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 = 0;
|
|
cache_keyid = 0;
|
|
}
|
|
|
|
if (trust > 0) {
|
|
sk->flags |= KEY_TRUSTED;
|
|
if (trust > 1)
|
|
sk->lifetime = current_time + trust;
|
|
else
|
|
sk->lifetime = 0;
|
|
return;
|
|
}
|
|
|
|
sk->flags &= ~KEY_TRUSTED; {
|
|
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(
|
|
keyid_t keyno
|
|
)
|
|
{
|
|
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) {
|
|
authkeynotfound++;
|
|
return (0);
|
|
} else if (!(sk->flags & KEY_TRUSTED)) {
|
|
authkeynotfound++;
|
|
return (0);
|
|
}
|
|
return (1);
|
|
}
|
|
|
|
|
|
|
|
#ifdef DES
|
|
/*
|
|
* DESauth_setkey - set a key into the key array
|
|
*/
|
|
void
|
|
DESauth_setkey(
|
|
keyid_t keyno,
|
|
const u_int32 *key
|
|
)
|
|
{
|
|
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_DES;
|
|
if (cache_keyid == keyno)
|
|
cache_flags = 0;
|
|
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_DES;
|
|
sk->lifetime = 0;
|
|
sk->next = key_hash[KEYHASH(keyno)];
|
|
key_hash[KEYHASH(keyno)] = sk;
|
|
authnumkeys++;
|
|
return;
|
|
}
|
|
#endif
|
|
|
|
#ifdef MD5
|
|
void
|
|
MD5auth_setkey(
|
|
keyid_t keyno,
|
|
const u_char *key,
|
|
const int len
|
|
)
|
|
{
|
|
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((char *)sk->k.MD5_key, (const char *)key,
|
|
sizeof(sk->k.MD5_key));
|
|
if ((sk->keylen = len) > sizeof(sk->k.MD5_key))
|
|
sk->keylen = sizeof(sk->k.MD5_key);
|
|
|
|
sk->flags |= KEY_MD5;
|
|
if (cache_keyid == keyno) {
|
|
cache_flags = 0;
|
|
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((char *)sk->k.MD5_key, (const char *)key,
|
|
sizeof(sk->k.MD5_key));
|
|
if ((sk->keylen = len) > sizeof(sk->k.MD5_key))
|
|
sk->keylen = sizeof(sk->k.MD5_key);
|
|
|
|
sk->keyid = keyno;
|
|
sk->flags = KEY_MD5;
|
|
sk->lifetime = 0;
|
|
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(void)
|
|
{
|
|
struct savekey *sk;
|
|
struct savekey **skp;
|
|
int i;
|
|
|
|
for (i = 0; i < HASHSIZE; i++) {
|
|
skp = &(key_hash[i]);
|
|
sk = key_hash[i];
|
|
/*
|
|
* Leave autokey keys alone.
|
|
*/
|
|
while (sk != 0 && sk->keyid <= NTP_MAXKEY) {
|
|
/*
|
|
* Don't loose info which keys are trusted.
|
|
*/
|
|
if (sk->flags & KEY_TRUSTED) {
|
|
memset(&sk->k, 0, sizeof(sk->k));
|
|
sk->lifetime = 0;
|
|
#ifdef MD5
|
|
sk->keylen = 0;
|
|
#endif
|
|
sk = sk->next;
|
|
} else {
|
|
*skp = sk->next;
|
|
authnumkeys--;
|
|
sk->next = authfreekeys;
|
|
authfreekeys = sk;
|
|
authnumfreekeys++;
|
|
sk = *skp;
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
/*
|
|
* auth_agekeys - delete keys whose lifetimes have expired
|
|
*/
|
|
void
|
|
auth_agekeys(void)
|
|
{
|
|
struct savekey *sk;
|
|
struct savekey *skp;
|
|
int i;
|
|
|
|
for (i = 0; i < HASHSIZE; i++) {
|
|
sk = skp = key_hash[i];
|
|
while (sk != 0) {
|
|
skp = sk->next;
|
|
if (sk->lifetime > 0 && current_time >
|
|
sk->lifetime) {
|
|
authtrust(sk->keyid, 0);
|
|
authkeyexpired++;
|
|
}
|
|
sk = skp;
|
|
}
|
|
}
|
|
#ifdef DEBUG
|
|
if (debug)
|
|
printf("auth_agekeys: at %lu keys %lu expired %lu\n",
|
|
current_time, authnumkeys, authkeyexpired);
|
|
#endif
|
|
}
|
|
|
|
/*
|
|
* authencrypt - generate message authenticator
|
|
*
|
|
* Returns length of authenticator field, zero if key not found.
|
|
*/
|
|
int
|
|
authencrypt(
|
|
keyid_t keyno,
|
|
u_int32 *pkt,
|
|
int length
|
|
)
|
|
{
|
|
|
|
/*
|
|
* A zero key identifier means the sender has not verified
|
|
* the last message was correctly authenticated. The MAC
|
|
* consists of a single word with value zero.
|
|
*/
|
|
authencryptions++;
|
|
pkt[length / 4] = htonl(keyno);
|
|
if (keyno == 0) {
|
|
return (4);
|
|
}
|
|
if (!authhavekey(keyno))
|
|
return (0);
|
|
|
|
#ifdef DES
|
|
if (cache_flags & KEY_DES)
|
|
return (DESauthencrypt(cache_key, pkt, length));
|
|
#endif
|
|
|
|
#ifdef MD5
|
|
if (cache_flags & KEY_MD5)
|
|
return (MD5authencrypt(cache_key, pkt, length));
|
|
#endif
|
|
return (0);
|
|
}
|
|
|
|
/*
|
|
* authdecrypt - verify message authenticator
|
|
*
|
|
* Returns one if authenticator valid, zero if invalid or key not found.
|
|
*/
|
|
int
|
|
authdecrypt(
|
|
keyid_t keyno,
|
|
u_int32 *pkt,
|
|
int length,
|
|
int size
|
|
)
|
|
{
|
|
|
|
/*
|
|
* A zero key identifier means the sender has not verified
|
|
* the last message was correctly authenticated. Nevertheless,
|
|
* the authenticator itself is considered valid.
|
|
*/
|
|
authdecryptions++;
|
|
if (keyno == 0)
|
|
return (0);
|
|
|
|
if (!authhavekey(keyno) || size < 4)
|
|
return (0);
|
|
|
|
#ifdef DES
|
|
if (cache_flags & KEY_DES)
|
|
return (DESauthdecrypt(cache_key, pkt, length, size));
|
|
#endif
|
|
|
|
#ifdef MD5
|
|
if (cache_flags & KEY_MD5)
|
|
return (MD5authdecrypt(cache_key, pkt, length, size));
|
|
#endif
|
|
|
|
return (0);
|
|
}
|