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