2 * ntp_crypto.c - NTP version 4 public key routines
10 #include <stdlib.h> /* strtoul */
11 #include <sys/types.h>
12 #include <sys/param.h>
17 #include "ntp_stdlib.h"
18 #include "ntp_unixtime.h"
19 #include "ntp_string.h"
20 #include "ntp_random.h"
21 #include "ntp_assert.h"
22 #include "ntp_calendar.h"
23 #include "ntp_leapsec.h"
25 #include "openssl/bn.h"
26 #include "openssl/err.h"
27 #include "openssl/evp.h"
28 #include "openssl/pem.h"
29 #include "openssl/rand.h"
30 #include "openssl/x509v3.h"
31 #include "libssl_compat.h"
34 #include "ntp_syscall.h"
35 #endif /* KERNEL_PLL */
38 * calcomp - compare two calendar structures, ignoring yearday and weekday; like strcmp
39 * No, it's not a plotter. If you don't understand that, you're too young.
41 static int calcomp(struct calendar *pjd1, struct calendar *pjd2)
43 int32_t diff; /* large enough to hold the signed difference between two uint16_t values */
45 diff = pjd1->year - pjd2->year;
46 if (diff < 0) return -1; else if (diff > 0) return 1;
47 /* same year; compare months */
48 diff = pjd1->month - pjd2->month;
49 if (diff < 0) return -1; else if (diff > 0) return 1;
50 /* same year and month; compare monthday */
51 diff = pjd1->monthday - pjd2->monthday;
52 if (diff < 0) return -1; else if (diff > 0) return 1;
53 /* same year and month and monthday; compare time */
54 diff = pjd1->hour - pjd2->hour;
55 if (diff < 0) return -1; else if (diff > 0) return 1;
56 diff = pjd1->minute - pjd2->minute;
57 if (diff < 0) return -1; else if (diff > 0) return 1;
58 diff = pjd1->second - pjd2->second;
59 if (diff < 0) return -1; else if (diff > 0) return 1;
65 * Extension field message format
67 * These are always signed and saved before sending in network byte
68 * order. They must be converted to and from host byte order for
72 * | op | len | <- extension pointer
76 * | timestamp | <- value pointer
93 * The CRYPTO_RESP bit is set to 0 for requests, 1 for responses.
94 * Requests carry the association ID of the receiver; responses carry
95 * the association ID of the sender. Some messages include only the
96 * operation/length and association ID words and so have length 8
97 * octets. Ohers include the value structure and associated value and
98 * signature fields. These messages include the timestamp, filestamp,
99 * value and signature words and so have length at least 24 octets. The
100 * signature and/or value fields can be empty, in which case the
101 * respective length words are zero. An empty value with nonempty
102 * signature is syntactically valid, but semantically questionable.
104 * The filestamp represents the time when a cryptographic data file such
105 * as a public/private key pair is created. It follows every reference
106 * depending on that file and serves as a means to obsolete earlier data
107 * of the same type. The timestamp represents the time when the
108 * cryptographic data of the message were last signed. Creation of a
109 * cryptographic data file or signing a message can occur only when the
110 * creator or signor is synchronized to an authoritative source and
111 * proventicated to a trusted authority.
113 * Note there are several conditions required for server trust. First,
114 * the public key on the server certificate must be verified, which can
115 * involve a hike along the certificate trail to a trusted host. Next,
116 * the server trust must be confirmed by one of several identity
117 * schemes. Valid cryptographic values are signed with attached
118 * timestamp and filestamp. Individual packet trust is confirmed
119 * relative to these values by a message digest with keys generated by a
120 * reverse-order pseudorandom hash.
122 * State decomposition. These flags are lit in the order given. They are
123 * dim only when the association is demobilized.
125 * CRYPTO_FLAG_ENAB Lit upon acceptance of a CRYPTO_ASSOC message
126 * CRYPTO_FLAG_CERT Lit when a self-digned trusted certificate is
128 * CRYPTO_FLAG_VRFY Lit when identity is confirmed.
129 * CRYPTO_FLAG_PROV Lit when the first signature is verified.
130 * CRYPTO_FLAG_COOK Lit when a valid cookie is accepted.
131 * CRYPTO_FLAG_AUTO Lit when valid autokey values are accepted.
132 * CRYPTO_FLAG_SIGN Lit when the server signed certificate is
134 * CRYPTO_FLAG_LEAP Lit when the leapsecond values are accepted.
139 #define TAI_1972 10 /* initial TAI offset (s) */
140 #define MAX_LEAP 100 /* max UTC leapseconds (s) */
141 #define VALUE_LEN (6 * 4) /* min response field length */
142 #define MAX_VALLEN (65535 - VALUE_LEN)
143 #define YEAR (60 * 60 * 24 * 365) /* seconds in year */
146 * Global cryptodata in host byte order
148 u_int32 crypto_flags = 0x0; /* status word */
149 int crypto_nid = KEY_TYPE_MD5; /* digest nid */
150 char *sys_hostname = NULL;
151 char *sys_groupname = NULL;
152 static char *host_filename = NULL; /* host file name */
153 static char *ident_filename = NULL; /* group file name */
156 * Global cryptodata in network byte order
158 struct cert_info *cinfo = NULL; /* certificate info/value cache */
159 struct cert_info *cert_host = NULL; /* host certificate */
160 struct pkey_info *pkinfo = NULL; /* key info/value cache */
161 struct value hostval; /* host value */
162 struct value pubkey; /* public key */
163 struct value tai_leap; /* leapseconds values */
164 struct pkey_info *iffkey_info = NULL; /* IFF keys */
165 struct pkey_info *gqkey_info = NULL; /* GQ keys */
166 struct pkey_info *mvkey_info = NULL; /* MV keys */
169 * Private cryptodata in host byte order
171 static char *passwd = NULL; /* private key password */
172 static EVP_PKEY *host_pkey = NULL; /* host key */
173 static EVP_PKEY *sign_pkey = NULL; /* sign key */
174 static const EVP_MD *sign_digest = NULL; /* sign digest */
175 static u_int sign_siglen; /* sign key length */
176 static char *rand_file = NULL; /* random seed file */
181 static int crypto_verify (struct exten *, struct value *,
183 static int crypto_encrypt (const u_char *, u_int, keyid_t *,
185 static int crypto_alice (struct peer *, struct value *);
186 static int crypto_alice2 (struct peer *, struct value *);
187 static int crypto_alice3 (struct peer *, struct value *);
188 static int crypto_bob (struct exten *, struct value *);
189 static int crypto_bob2 (struct exten *, struct value *);
190 static int crypto_bob3 (struct exten *, struct value *);
191 static int crypto_iff (struct exten *, struct peer *);
192 static int crypto_gq (struct exten *, struct peer *);
193 static int crypto_mv (struct exten *, struct peer *);
194 static int crypto_send (struct exten *, struct value *, int);
195 static tstamp_t crypto_time (void);
196 static void asn_to_calendar (ASN1_TIME *, struct calendar*);
197 static struct cert_info *cert_parse (const u_char *, long, tstamp_t);
198 static int cert_sign (struct exten *, struct value *);
199 static struct cert_info *cert_install (struct exten *, struct peer *);
200 static int cert_hike (struct peer *, struct cert_info *);
201 static void cert_free (struct cert_info *);
202 static struct pkey_info *crypto_key (char *, char *, sockaddr_u *);
203 static void bighash (BIGNUM *, BIGNUM *);
204 static struct cert_info *crypto_cert (char *);
205 static u_int exten_payload_size(const struct exten *);
209 readlink(char * link, char * file, int len) {
215 * session_key - generate session key
217 * This routine generates a session key from the source address,
218 * destination address, key ID and private value. The value of the
219 * session key is the MD5 hash of these values, while the next key ID is
220 * the first four octets of the hash.
222 * Returns the next key ID or 0 if there is no destination address.
226 sockaddr_u *srcadr, /* source address */
227 sockaddr_u *dstadr, /* destination address */
228 keyid_t keyno, /* key ID */
229 keyid_t private, /* private value */
230 u_long lifetime /* key lifetime */
233 EVP_MD_CTX *ctx; /* message digest context */
234 u_char dgst[EVP_MAX_MD_SIZE]; /* message digest */
235 keyid_t keyid; /* key identifer */
236 u_int32 header[10]; /* data in network byte order */
243 * Generate the session key and key ID. If the lifetime is
244 * greater than zero, install the key and call it trusted.
249 header[0] = NSRCADR(srcadr);
250 header[1] = NSRCADR(dstadr);
251 header[2] = htonl(keyno);
252 header[3] = htonl(private);
253 hdlen = 4 * sizeof(u_int32);
257 memcpy(&header[0], PSOCK_ADDR6(srcadr),
258 sizeof(struct in6_addr));
259 memcpy(&header[4], PSOCK_ADDR6(dstadr),
260 sizeof(struct in6_addr));
261 header[8] = htonl(keyno);
262 header[9] = htonl(private);
263 hdlen = 10 * sizeof(u_int32);
266 ctx = EVP_MD_CTX_new();
267 EVP_DigestInit(ctx, EVP_get_digestbynid(crypto_nid));
268 EVP_DigestUpdate(ctx, (u_char *)header, hdlen);
269 EVP_DigestFinal(ctx, dgst, &len);
270 EVP_MD_CTX_free(ctx);
271 memcpy(&keyid, dgst, 4);
272 keyid = ntohl(keyid);
274 MD5auth_setkey(keyno, crypto_nid, dgst, len, NULL);
275 authtrust(keyno, lifetime);
277 DPRINTF(2, ("session_key: %s > %s %08x %08x hash %08x life %lu\n",
278 stoa(srcadr), stoa(dstadr), keyno,
279 private, keyid, lifetime));
286 * make_keylist - generate key list
290 * XEVNT_ERR protocol error
292 * This routine constructs a pseudo-random sequence by repeatedly
293 * hashing the session key starting from a given source address,
294 * destination address, private value and the next key ID of the
295 * preceeding session key. The last entry on the list is saved along
296 * with its sequence number and public signature.
300 struct peer *peer, /* peer structure pointer */
301 struct interface *dstadr /* interface */
304 EVP_MD_CTX *ctx; /* signature context */
305 tstamp_t tstamp; /* NTP timestamp */
306 struct autokey *ap; /* autokey pointer */
307 struct value *vp; /* value pointer */
308 keyid_t keyid = 0; /* next key ID */
309 keyid_t cookie; /* private value */
318 * Allocate the key list if necessary.
320 tstamp = crypto_time();
321 if (peer->keylist == NULL)
322 peer->keylist = eallocarray(NTP_MAXSESSION,
326 * Generate an initial key ID which is unique and greater than
330 keyid = ntp_random() & 0xffffffff;
331 if (keyid <= NTP_MAXKEY)
334 if (authhavekey(keyid))
340 * Generate up to NTP_MAXSESSION session keys. Stop if the
341 * next one would not be unique or not a session key ID or if
342 * it would expire before the next poll. The private value
343 * included in the hash is zero if broadcast mode, the peer
344 * cookie if client mode or the host cookie if symmetric modes.
346 mpoll = 1 << min(peer->ppoll, peer->hpoll);
347 lifetime = min(1U << sys_automax, NTP_MAXSESSION * mpoll);
348 if (peer->hmode == MODE_BROADCAST)
351 cookie = peer->pcookie;
352 for (i = 0; i < NTP_MAXSESSION; i++) {
353 peer->keylist[i] = keyid;
355 keyid = session_key(&dstadr->sin, &peer->srcadr, keyid,
356 cookie, lifetime + mpoll);
358 if (auth_havekey(keyid) || keyid <= NTP_MAXKEY ||
359 lifetime < 0 || tstamp == 0)
364 * Save the last session key ID, sequence number and timestamp,
365 * then sign these values for later retrieval by the clients. Be
366 * careful not to use invalid key media. Use the public values
367 * timestamp as filestamp.
371 vp->ptr = emalloc(sizeof(struct autokey));
372 ap = (struct autokey *)vp->ptr;
373 ap->seq = htonl(peer->keynumber);
374 ap->key = htonl(keyid);
375 vp->tstamp = htonl(tstamp);
376 vp->fstamp = hostval.tstamp;
377 vp->vallen = htonl(sizeof(struct autokey));
381 vp->sig = emalloc(sign_siglen);
382 ctx = EVP_MD_CTX_new();
383 EVP_SignInit(ctx, sign_digest);
384 EVP_SignUpdate(ctx, (u_char *)vp, 12);
385 EVP_SignUpdate(ctx, vp->ptr, sizeof(struct autokey));
386 if (EVP_SignFinal(ctx, vp->sig, &len, sign_pkey)) {
387 INSIST(len <= sign_siglen);
388 vp->siglen = htonl(len);
389 peer->flags |= FLAG_ASSOC;
391 EVP_MD_CTX_free(ctx);
393 DPRINTF(1, ("make_keys: %d %08x %08x ts %u fs %u poll %d\n",
394 peer->keynumber, keyid, cookie, ntohl(vp->tstamp),
395 ntohl(vp->fstamp), peer->hpoll));
401 * crypto_recv - parse extension fields
403 * This routine is called when the packet has been matched to an
404 * association and passed sanity, format and MAC checks. We believe the
405 * extension field values only if the field has proper format and
406 * length, the timestamp and filestamp are valid and the signature has
407 * valid length and is verified. There are a few cases where some values
408 * are believed even if the signature fails, but only if the proventic
413 * XEVNT_ERR protocol error
414 * XEVNT_LEN bad field format or length
418 struct peer *peer, /* peer structure pointer */
419 struct recvbuf *rbufp /* packet buffer pointer */
422 const EVP_MD *dp; /* message digest algorithm */
423 u_int32 *pkt; /* receive packet pointer */
424 struct autokey *ap, *bp; /* autokey pointer */
425 struct exten *ep, *fp; /* extension pointers */
426 struct cert_info *xinfo; /* certificate info pointer */
427 int macbytes; /* length of MAC field, signed by intention */
428 int authlen; /* offset of MAC field */
429 associd_t associd; /* association ID */
430 tstamp_t fstamp = 0; /* filestamp */
431 u_int len; /* extension field length */
432 u_int code; /* extension field opcode */
433 u_int vallen = 0; /* value length */
434 X509 *cert; /* X509 certificate */
435 char statstr[NTP_MAXSTRLEN]; /* statistics for filegen */
436 keyid_t cookie; /* crumbles */
437 int hismode; /* packet mode */
443 * Initialize. Note that the packet has already been checked for
444 * valid format and extension field lengths. First extract the
445 * field length, command code and association ID in host byte
446 * order. These are used with all commands and modes. Then check
447 * the version number, which must be 2, and length, which must
448 * be at least 8 for requests and VALUE_LEN (24) for responses.
449 * Packets that fail either test sink without a trace. The
450 * association ID is saved only if nonzero.
452 authlen = LEN_PKT_NOMAC;
453 hismode = (int)PKT_MODE((&rbufp->recv_pkt)->li_vn_mode);
454 while ((macbytes = rbufp->recv_length - authlen) > (int)MAX_MAC_LEN) {
455 /* We can be reasonably sure that we can read at least
456 * the opcode and the size field here. More stringent
457 * checks follow up shortly.
459 pkt = (u_int32 *)&rbufp->recv_pkt + authlen / 4;
460 ep = (struct exten *)pkt;
461 code = ntohl(ep->opcode) & 0xffff0000;
462 len = ntohl(ep->opcode) & 0x0000ffff;
463 // HMS: Why pkt[1] instead of ep->associd ?
464 associd = (associd_t)ntohl(pkt[1]);
466 DPRINTF(1, ("crypto_recv: flags 0x%x ext offset %d len %u code 0x%x associd %d\n",
467 peer->crypto, authlen, len, code >> 16,
471 * Check version number and field length. If bad,
472 * quietly ignore the packet.
474 if (((code >> 24) & 0x3f) != CRYPTO_VN || len < 8) {
476 code |= CRYPTO_ERROR;
479 /* Check if the declared size fits into the remaining
480 * buffer. We *know* 'macbytes' > 0 here!
482 if (len > (u_int)macbytes) {
483 DPRINTF(1, ("crypto_recv: possible attack detected, associd %d\n",
488 /* Check if the paylod of the extension fits into the
491 if (len >= VALUE_LEN) {
492 fstamp = ntohl(ep->fstamp);
493 vallen = ntohl(ep->vallen);
495 * Bug 2761: I hope this isn't too early...
498 || len - VALUE_LEN < vallen)
504 * Install status word, host name, signature scheme and
505 * association ID. In OpenSSL the signature algorithm is
506 * bound to the digest algorithm, so the NID completely
507 * defines the signature scheme. Note the request and
508 * response are identical, but neither is validated by
509 * signature. The request is processed here only in
510 * symmetric modes. The server name field might be
511 * useful to implement access controls in future.
516 * If our state machine is running when this
517 * message arrives, the other fellow might have
518 * restarted. However, this could be an
519 * intruder, so just clamp the poll interval and
520 * find out for ourselves. Otherwise, pass the
521 * extension field to the transmit side.
523 if (peer->crypto & CRYPTO_FLAG_CERT) {
528 if (peer->assoc != associd) {
532 free(peer->cmmd); /* will be set again! */
536 fp->associd = htonl(peer->associd);
540 case CRYPTO_ASSOC | CRYPTO_RESP:
543 * Discard the message if it has already been
544 * stored or the message has been amputated.
547 if (peer->assoc != associd)
551 INSIST(len >= VALUE_LEN);
552 if (vallen == 0 || vallen > MAXHOSTNAME ||
553 len - VALUE_LEN < vallen) {
557 DPRINTF(1, ("crypto_recv: ident host 0x%x %d server 0x%x %d\n",
558 crypto_flags, peer->associd, fstamp,
560 temp32 = crypto_flags & CRYPTO_FLAG_MASK;
563 * If the client scheme is PC, the server scheme
564 * must be PC. The public key and identity are
565 * presumed valid, so we skip the certificate
566 * and identity exchanges and move immediately
567 * to the cookie exchange which confirms the
570 if (crypto_flags & CRYPTO_FLAG_PRIV) {
571 if (!(fstamp & CRYPTO_FLAG_PRIV)) {
575 fstamp |= CRYPTO_FLAG_CERT |
576 CRYPTO_FLAG_VRFY | CRYPTO_FLAG_SIGN;
579 * It is an error if either peer supports
580 * identity, but the other does not.
582 } else if (hismode == MODE_ACTIVE || hismode ==
584 if ((temp32 && !(fstamp &
585 CRYPTO_FLAG_MASK)) ||
586 (!temp32 && (fstamp &
587 CRYPTO_FLAG_MASK))) {
594 * Discard the message if the signature digest
595 * NID is not supported.
597 temp32 = (fstamp >> 16) & 0xffff;
599 (const EVP_MD *)EVP_get_digestbynid(temp32);
606 * Save status word, host name and message
607 * digest/signature type. If this is from a
608 * broadcast and the association ID has changed,
609 * request the autokey values.
611 peer->assoc = associd;
612 if (hismode == MODE_SERVER)
613 fstamp |= CRYPTO_FLAG_AUTO;
614 if (!(fstamp & CRYPTO_FLAG_TAI))
615 fstamp |= CRYPTO_FLAG_LEAP;
616 RAND_bytes((u_char *)&peer->hcookie, 4);
617 peer->crypto = fstamp;
619 if (peer->subject != NULL)
621 peer->subject = emalloc(vallen + 1);
622 memcpy(peer->subject, ep->pkt, vallen);
623 peer->subject[vallen] = '\0';
624 if (peer->issuer != NULL)
626 peer->issuer = estrdup(peer->subject);
627 snprintf(statstr, sizeof(statstr),
628 "assoc %d %d host %s %s", peer->associd,
629 peer->assoc, peer->subject,
631 record_crypto_stats(&peer->srcadr, statstr);
632 DPRINTF(1, ("crypto_recv: %s\n", statstr));
636 * Decode X509 certificate in ASN.1 format and extract
637 * the data containing, among other things, subject
638 * name and public key. In the default identification
639 * scheme, the certificate trail is followed to a self
640 * signed trusted certificate.
642 case CRYPTO_CERT | CRYPTO_RESP:
645 * Discard the message if empty or invalid.
650 if ((rval = crypto_verify(ep, NULL, peer)) !=
655 * Scan the certificate list to delete old
656 * versions and link the newest version first on
657 * the list. Then, verify the signature. If the
658 * certificate is bad or missing, just ignore
661 if ((xinfo = cert_install(ep, peer)) == NULL) {
665 if ((rval = cert_hike(peer, xinfo)) != XEVNT_OK)
669 * We plug in the public key and lifetime from
670 * the first certificate received. However, note
671 * that this certificate might not be signed by
672 * the server, so we can't check the
673 * signature/digest NID.
675 if (peer->pkey == NULL) {
676 puch = xinfo->cert.ptr;
677 cert = d2i_X509(NULL, &puch,
678 ntohl(xinfo->cert.vallen));
679 peer->pkey = X509_get_pubkey(cert);
682 peer->flash &= ~TEST8;
684 snprintf(statstr, sizeof(statstr),
685 "cert %s %s 0x%x %s (%u) fs %u",
686 xinfo->subject, xinfo->issuer, xinfo->flags,
687 OBJ_nid2ln(temp32), temp32,
689 record_crypto_stats(&peer->srcadr, statstr);
690 DPRINTF(1, ("crypto_recv: %s\n", statstr));
694 * Schnorr (IFF) identity scheme. This scheme is
695 * designed for use with shared secret server group keys
696 * and where the certificate may be generated by a third
697 * party. The client sends a challenge to the server,
698 * which performs a calculation and returns the result.
699 * A positive result is possible only if both client and
700 * server contain the same secret group key.
702 case CRYPTO_IFF | CRYPTO_RESP:
705 * Discard the message if invalid.
707 if ((rval = crypto_verify(ep, NULL, peer)) !=
712 * If the challenge matches the response, the
713 * server public key, signature and identity are
714 * all verified at the same time. The server is
715 * declared trusted, so we skip further
716 * certificate exchanges and move immediately to
717 * the cookie exchange.
719 if ((rval = crypto_iff(ep, peer)) != XEVNT_OK)
722 peer->crypto |= CRYPTO_FLAG_VRFY;
723 peer->flash &= ~TEST8;
724 snprintf(statstr, sizeof(statstr), "iff %s fs %u",
725 peer->issuer, ntohl(ep->fstamp));
726 record_crypto_stats(&peer->srcadr, statstr);
727 DPRINTF(1, ("crypto_recv: %s\n", statstr));
731 * Guillou-Quisquater (GQ) identity scheme. This scheme
732 * is designed for use with public certificates carrying
733 * the GQ public key in an extension field. The client
734 * sends a challenge to the server, which performs a
735 * calculation and returns the result. A positive result
736 * is possible only if both client and server contain
737 * the same group key and the server has the matching GQ
740 case CRYPTO_GQ | CRYPTO_RESP:
743 * Discard the message if invalid
745 if ((rval = crypto_verify(ep, NULL, peer)) !=
750 * If the challenge matches the response, the
751 * server public key, signature and identity are
752 * all verified at the same time. The server is
753 * declared trusted, so we skip further
754 * certificate exchanges and move immediately to
755 * the cookie exchange.
757 if ((rval = crypto_gq(ep, peer)) != XEVNT_OK)
760 peer->crypto |= CRYPTO_FLAG_VRFY;
761 peer->flash &= ~TEST8;
762 snprintf(statstr, sizeof(statstr), "gq %s fs %u",
763 peer->issuer, ntohl(ep->fstamp));
764 record_crypto_stats(&peer->srcadr, statstr);
765 DPRINTF(1, ("crypto_recv: %s\n", statstr));
769 * Mu-Varadharajan (MV) identity scheme. This scheme is
770 * designed for use with three levels of trust, trusted
771 * host, server and client. The trusted host key is
772 * opaque to servers and clients; the server keys are
773 * opaque to clients and each client key is different.
774 * Client keys can be revoked without requiring new key
777 case CRYPTO_MV | CRYPTO_RESP:
780 * Discard the message if invalid.
782 if ((rval = crypto_verify(ep, NULL, peer)) !=
787 * If the challenge matches the response, the
788 * server public key, signature and identity are
789 * all verified at the same time. The server is
790 * declared trusted, so we skip further
791 * certificate exchanges and move immediately to
792 * the cookie exchange.
794 if ((rval = crypto_mv(ep, peer)) != XEVNT_OK)
797 peer->crypto |= CRYPTO_FLAG_VRFY;
798 peer->flash &= ~TEST8;
799 snprintf(statstr, sizeof(statstr), "mv %s fs %u",
800 peer->issuer, ntohl(ep->fstamp));
801 record_crypto_stats(&peer->srcadr, statstr);
802 DPRINTF(1, ("crypto_recv: %s\n", statstr));
807 * Cookie response in client and symmetric modes. If the
808 * cookie bit is set, the working cookie is the EXOR of
809 * the current and new values.
811 case CRYPTO_COOK | CRYPTO_RESP:
814 * Discard the message if invalid or signature
815 * not verified with respect to the cookie
818 if ((rval = crypto_verify(ep, &peer->cookval,
823 * Decrypt the cookie, hunting all the time for
826 if (vallen == (u_int)EVP_PKEY_size(host_pkey)) {
827 RSA *rsa = EVP_PKEY_get0_RSA(host_pkey);
828 u_int32 *cookiebuf = malloc(RSA_size(rsa));
834 if (RSA_private_decrypt(vallen,
838 RSA_PKCS1_OAEP_PADDING) != 4) {
843 cookie = ntohl(*cookiebuf);
852 * Install cookie values and light the cookie
853 * bit. If this is not broadcast client mode, we
857 if (hismode == MODE_ACTIVE || hismode ==
859 peer->pcookie = peer->hcookie ^ cookie;
861 peer->pcookie = cookie;
862 peer->crypto |= CRYPTO_FLAG_COOK;
863 peer->flash &= ~TEST8;
864 snprintf(statstr, sizeof(statstr),
865 "cook %x ts %u fs %u", peer->pcookie,
866 ntohl(ep->tstamp), ntohl(ep->fstamp));
867 record_crypto_stats(&peer->srcadr, statstr);
868 DPRINTF(1, ("crypto_recv: %s\n", statstr));
872 * Install autokey values in broadcast client and
873 * symmetric modes. We have to do this every time the
874 * sever/peer cookie changes or a new keylist is
875 * rolled. Ordinarily, this is automatic as this message
876 * is piggybacked on the first NTP packet sent upon
877 * either of these events. Note that a broadcast client
878 * or symmetric peer can receive this response without a
881 case CRYPTO_AUTO | CRYPTO_RESP:
884 * Discard the message if invalid or signature
885 * not verified with respect to the receive
888 if ((rval = crypto_verify(ep, &peer->recval,
893 * Discard the message if a broadcast client and
894 * the association ID does not match. This might
895 * happen if a broacast server restarts the
896 * protocol. A protocol restart will occur at
897 * the next ASSOC message.
899 if ((peer->cast_flags & MDF_BCLNT) &&
900 peer->assoc != associd)
904 * Install autokey values and light the
905 * autokey bit. This is not hard.
910 if (peer->recval.ptr == NULL)
912 emalloc(sizeof(struct autokey));
913 bp = (struct autokey *)peer->recval.ptr;
914 peer->recval.tstamp = ep->tstamp;
915 peer->recval.fstamp = ep->fstamp;
916 ap = (struct autokey *)ep->pkt;
917 bp->seq = ntohl(ap->seq);
918 bp->key = ntohl(ap->key);
919 peer->pkeyid = bp->key;
920 peer->crypto |= CRYPTO_FLAG_AUTO;
921 peer->flash &= ~TEST8;
922 snprintf(statstr, sizeof(statstr),
923 "auto seq %d key %x ts %u fs %u", bp->seq,
924 bp->key, ntohl(ep->tstamp),
926 record_crypto_stats(&peer->srcadr, statstr);
927 DPRINTF(1, ("crypto_recv: %s\n", statstr));
931 * X509 certificate sign response. Validate the
932 * certificate signed by the server and install. Later
933 * this can be provided to clients of this server in
934 * lieu of the self signed certificate in order to
935 * validate the public key.
937 case CRYPTO_SIGN | CRYPTO_RESP:
940 * Discard the message if invalid.
942 if ((rval = crypto_verify(ep, NULL, peer)) !=
947 * Scan the certificate list to delete old
948 * versions and link the newest version first on
951 if ((xinfo = cert_install(ep, peer)) == NULL) {
955 peer->crypto |= CRYPTO_FLAG_SIGN;
956 peer->flash &= ~TEST8;
958 snprintf(statstr, sizeof(statstr),
959 "sign %s %s 0x%x %s (%u) fs %u",
960 xinfo->subject, xinfo->issuer, xinfo->flags,
961 OBJ_nid2ln(temp32), temp32,
963 record_crypto_stats(&peer->srcadr, statstr);
964 DPRINTF(1, ("crypto_recv: %s\n", statstr));
968 * Install leapseconds values. While the leapsecond
969 * values epoch, TAI offset and values expiration epoch
970 * are retained, only the current TAI offset is provided
971 * via the kernel to other applications.
973 case CRYPTO_LEAP | CRYPTO_RESP:
975 * Discard the message if invalid. We can't
976 * compare the value timestamps here, as they
977 * can be updated by different servers.
979 rval = crypto_verify(ep, NULL, peer);
980 if ((rval != XEVNT_OK ) ||
981 (vallen != 3*sizeof(uint32_t)) )
984 /* Check if we can update the basic TAI offset
985 * for our current leap frame. This is a hack
986 * and ignores the time stamps in the autokey
989 if (sys_leap != LEAP_NOTINSYNC)
990 leapsec_autokey_tai(ntohl(ep->pkt[0]),
991 rbufp->recv_time.l_ui, NULL);
992 tai_leap.tstamp = ep->tstamp;
993 tai_leap.fstamp = ep->fstamp;
995 mprintf_event(EVNT_TAI, peer,
996 "%d seconds", ntohl(ep->pkt[0]));
997 peer->crypto |= CRYPTO_FLAG_LEAP;
998 peer->flash &= ~TEST8;
999 snprintf(statstr, sizeof(statstr),
1000 "leap TAI offset %d at %u expire %u fs %u",
1001 ntohl(ep->pkt[0]), ntohl(ep->pkt[1]),
1002 ntohl(ep->pkt[2]), ntohl(ep->fstamp));
1003 record_crypto_stats(&peer->srcadr, statstr);
1004 DPRINTF(1, ("crypto_recv: %s\n", statstr));
1008 * We come here in symmetric modes for miscellaneous
1009 * commands that have value fields but are processed on
1010 * the transmit side. All we need do here is check for
1011 * valid field length. Note that ASSOC is handled
1020 if (len < VALUE_LEN) {
1027 * We come here in symmetric modes for requests
1028 * requiring a response (above plus AUTO and LEAP) and
1029 * for responses. If a request, save the extension field
1030 * for later; invalid requests will be caught on the
1031 * transmit side. If an error or invalid response,
1032 * declare a protocol error.
1035 if (code & (CRYPTO_RESP | CRYPTO_ERROR)) {
1037 } else if (peer->cmmd == NULL) {
1039 memcpy(fp, ep, len);
1045 * The first error found terminates the extension field
1046 * scan and we return the laundry to the caller.
1048 if (rval != XEVNT_OK) {
1049 snprintf(statstr, sizeof(statstr),
1050 "%04x %d %02x %s", htonl(ep->opcode),
1051 associd, rval, eventstr(rval));
1052 record_crypto_stats(&peer->srcadr, statstr);
1053 DPRINTF(1, ("crypto_recv: %s\n", statstr));
1056 authlen += (len + 3) / 4 * 4;
1063 * crypto_xmit - construct extension fields
1065 * This routine is called both when an association is configured and
1066 * when one is not. The only case where this matters is to retrieve the
1067 * autokey information, in which case the caller has to provide the
1068 * association ID to match the association.
1070 * Side effect: update the packet offset.
1074 * XEVNT_CRT bad or missing certificate
1075 * XEVNT_ERR protocol error
1076 * XEVNT_LEN bad field format or length
1077 * XEVNT_PER host certificate expired
1081 struct peer *peer, /* peer structure pointer */
1082 struct pkt *xpkt, /* transmit packet pointer */
1083 struct recvbuf *rbufp, /* receive buffer pointer */
1084 int start, /* offset to extension field */
1085 struct exten *ep, /* extension pointer */
1086 keyid_t cookie /* session cookie */
1089 struct exten *fp; /* extension pointers */
1090 struct cert_info *cp, *xp, *yp; /* cert info/value pointer */
1091 sockaddr_u *srcadr_sin; /* source address */
1092 u_int32 *pkt; /* packet pointer */
1093 u_int opcode; /* extension field opcode */
1094 char certname[MAXHOSTNAME + 1]; /* subject name buffer */
1095 char statstr[NTP_MAXSTRLEN]; /* statistics for filegen */
1097 struct calendar tscal;
1106 * Generate the requested extension field request code, length
1107 * and association ID. If this is a response and the host is not
1108 * synchronized, light the error bit and go home.
1110 pkt = (u_int32 *)xpkt + start / 4;
1111 fp = (struct exten *)pkt;
1112 opcode = ntohl(ep->opcode);
1114 srcadr_sin = &peer->srcadr;
1115 if (!(opcode & CRYPTO_RESP))
1116 peer->opcode = ep->opcode;
1118 srcadr_sin = &rbufp->recv_srcadr;
1120 associd = (associd_t) ntohl(ep->associd);
1122 fp->opcode = htonl((opcode & 0xffff0000) | len);
1123 fp->associd = ep->associd;
1125 tstamp = crypto_time();
1126 switch (opcode & 0xffff0000) {
1129 * Send association request and response with status word and
1130 * host name. Note, this message is not signed and the filestamp
1131 * contains only the status word.
1134 case CRYPTO_ASSOC | CRYPTO_RESP:
1135 len = crypto_send(fp, &hostval, start);
1136 fp->fstamp = htonl(crypto_flags);
1140 * Send certificate request. Use the values from the extension
1144 memset(&vtemp, 0, sizeof(vtemp));
1145 vtemp.tstamp = ep->tstamp;
1146 vtemp.fstamp = ep->fstamp;
1147 vtemp.vallen = ep->vallen;
1148 vtemp.ptr = (u_char *)ep->pkt;
1149 len = crypto_send(fp, &vtemp, start);
1153 * Send sign request. Use the host certificate, which is self-
1154 * signed and may or may not be trusted.
1157 (void)ntpcal_ntp_to_date(&tscal, tstamp, NULL);
1158 if ((calcomp(&tscal, &(cert_host->first)) < 0)
1159 || (calcomp(&tscal, &(cert_host->last)) > 0))
1162 len = crypto_send(fp, &cert_host->cert, start);
1166 * Send certificate response. Use the name in the extension
1167 * field to find the certificate in the cache. If the request
1168 * contains no subject name, assume the name of this host. This
1169 * is for backwards compatibility. Private certificates are
1172 * There may be several certificates matching the request. First
1173 * choice is a self-signed trusted certificate; second choice is
1174 * any certificate signed by another host. There is no third
1177 case CRYPTO_CERT | CRYPTO_RESP:
1178 vallen = exten_payload_size(ep); /* Must be <64k */
1179 if (vallen == 0 || vallen >= sizeof(certname) ) {
1185 * Find all public valid certificates with matching
1186 * subject. If a self-signed, trusted certificate is
1187 * found, use that certificate. If not, use the last non
1188 * self-signed certificate.
1190 memcpy(certname, ep->pkt, vallen);
1191 certname[vallen] = '\0';
1193 for (cp = cinfo; cp != NULL; cp = cp->link) {
1194 if (cp->flags & (CERT_PRIV | CERT_ERROR))
1197 if (strcmp(certname, cp->subject) != 0)
1200 if (strcmp(certname, cp->issuer) != 0)
1202 else if (cp ->flags & CERT_TRUST)
1208 * Be careful who you trust. If the certificate is not
1209 * found, return an empty response. Note that we dont
1210 * enforce lifetimes here.
1212 * The timestamp and filestamp are taken from the
1213 * certificate value structure. For all certificates the
1214 * timestamp is the latest signature update time. For
1215 * host and imported certificates the filestamp is the
1216 * creation epoch. For signed certificates the filestamp
1217 * is the creation epoch of the trusted certificate at
1218 * the root of the certificate trail. In principle, this
1219 * allows strong checking for signature masquerade.
1229 len = crypto_send(fp, &xp->cert, start);
1233 * Send challenge in Schnorr (IFF) identity scheme.
1237 break; /* hack attack */
1239 if ((rval = crypto_alice(peer, &vtemp)) == XEVNT_OK) {
1240 len = crypto_send(fp, &vtemp, start);
1246 * Send response in Schnorr (IFF) identity scheme.
1248 case CRYPTO_IFF | CRYPTO_RESP:
1249 if ((rval = crypto_bob(ep, &vtemp)) == XEVNT_OK) {
1250 len = crypto_send(fp, &vtemp, start);
1256 * Send challenge in Guillou-Quisquater (GQ) identity scheme.
1260 break; /* hack attack */
1262 if ((rval = crypto_alice2(peer, &vtemp)) == XEVNT_OK) {
1263 len = crypto_send(fp, &vtemp, start);
1269 * Send response in Guillou-Quisquater (GQ) identity scheme.
1271 case CRYPTO_GQ | CRYPTO_RESP:
1272 if ((rval = crypto_bob2(ep, &vtemp)) == XEVNT_OK) {
1273 len = crypto_send(fp, &vtemp, start);
1279 * Send challenge in MV identity scheme.
1283 break; /* hack attack */
1285 if ((rval = crypto_alice3(peer, &vtemp)) == XEVNT_OK) {
1286 len = crypto_send(fp, &vtemp, start);
1292 * Send response in MV identity scheme.
1294 case CRYPTO_MV | CRYPTO_RESP:
1295 if ((rval = crypto_bob3(ep, &vtemp)) == XEVNT_OK) {
1296 len = crypto_send(fp, &vtemp, start);
1302 * Send certificate sign response. The integrity of the request
1303 * certificate has already been verified on the receive side.
1304 * Sign the response using the local server key. Use the
1305 * filestamp from the request and use the timestamp as the
1306 * current time. Light the error bit if the certificate is
1307 * invalid or contains an unverified signature.
1309 case CRYPTO_SIGN | CRYPTO_RESP:
1310 if ((rval = cert_sign(ep, &vtemp)) == XEVNT_OK) {
1311 len = crypto_send(fp, &vtemp, start);
1317 * Send public key and signature. Use the values from the public
1321 len = crypto_send(fp, &pubkey, start);
1325 * Encrypt and send cookie and signature. Light the error bit if
1326 * anything goes wrong.
1328 case CRYPTO_COOK | CRYPTO_RESP:
1329 vallen = ntohl(ep->vallen); /* Must be <64k */
1331 || (vallen >= MAX_VALLEN)
1332 || (opcode & 0x0000ffff) < VALUE_LEN + vallen) {
1339 tcookie = peer->hcookie;
1340 if ((rval = crypto_encrypt((const u_char *)ep->pkt, vallen, &tcookie, &vtemp))
1342 len = crypto_send(fp, &vtemp, start);
1348 * Find peer and send autokey data and signature in broadcast
1349 * server and symmetric modes. Use the values in the autokey
1350 * structure. If no association is found, either the server has
1351 * restarted with new associations or some perp has replayed an
1352 * old message, in which case light the error bit.
1354 case CRYPTO_AUTO | CRYPTO_RESP:
1356 if ((peer = findpeerbyassoc(associd)) == NULL) {
1361 peer->flags &= ~FLAG_ASSOC;
1362 len = crypto_send(fp, &peer->sndval, start);
1366 * Send leapseconds values and signature. Use the values from
1367 * the tai structure. If no table has been loaded, just send an
1370 case CRYPTO_LEAP | CRYPTO_RESP:
1371 len = crypto_send(fp, &tai_leap, start);
1375 * Default - Send a valid command for unknown requests; send
1376 * an error response for unknown resonses.
1379 if (opcode & CRYPTO_RESP)
1384 * In case of error, flame the log. If a request, toss the
1385 * puppy; if a response, return so the sender can flame, too.
1387 if (rval != XEVNT_OK) {
1390 uint32 = CRYPTO_ERROR;
1392 fp->opcode |= htonl(uint32);
1393 snprintf(statstr, sizeof(statstr),
1394 "%04x %d %02x %s", opcode, associd, rval,
1396 record_crypto_stats(srcadr_sin, statstr);
1397 DPRINTF(1, ("crypto_xmit: %s\n", statstr));
1398 if (!(opcode & CRYPTO_RESP))
1401 DPRINTF(1, ("crypto_xmit: flags 0x%x offset %d len %d code 0x%x associd %d\n",
1402 crypto_flags, start, len, opcode >> 16, associd));
1408 * crypto_verify - verify the extension field value and signature
1412 * XEVNT_ERR protocol error
1413 * XEVNT_FSP bad filestamp
1414 * XEVNT_LEN bad field format or length
1415 * XEVNT_PUB bad or missing public key
1416 * XEVNT_SGL bad signature length
1417 * XEVNT_SIG signature not verified
1418 * XEVNT_TSP bad timestamp
1422 struct exten *ep, /* extension pointer */
1423 struct value *vp, /* value pointer */
1424 struct peer *peer /* peer structure pointer */
1427 EVP_PKEY *pkey; /* server public key */
1428 EVP_MD_CTX *ctx; /* signature context */
1429 tstamp_t tstamp, tstamp1 = 0; /* timestamp */
1430 tstamp_t fstamp, fstamp1 = 0; /* filestamp */
1431 u_int vallen; /* value length */
1432 u_int siglen; /* signature length */
1437 * We are extremely parannoyed. We require valid opcode, length,
1438 * association ID, timestamp, filestamp, public key, digest,
1439 * signature length and signature, where relevant. Note that
1440 * preliminary length checks are done in the main loop.
1442 len = ntohl(ep->opcode) & 0x0000ffff;
1443 opcode = ntohl(ep->opcode) & 0xffff0000;
1446 * Check for valid value header, association ID and extension
1447 * field length. Remember, it is not an error to receive an
1448 * unsolicited response; however, the response ID must match
1449 * the association ID.
1451 if (opcode & CRYPTO_ERROR)
1454 if (len < VALUE_LEN)
1457 if (opcode == (CRYPTO_AUTO | CRYPTO_RESP) && (peer->pmode ==
1458 MODE_BROADCAST || (peer->cast_flags & MDF_BCLNT))) {
1459 if (ntohl(ep->associd) != peer->assoc)
1462 if (ntohl(ep->associd) != peer->associd)
1467 * We have a valid value header. Check for valid value and
1468 * signature field lengths. The extension field length must be
1469 * long enough to contain the value header, value and signature.
1470 * Note both the value and signature field lengths are rounded
1471 * up to the next word (4 octets).
1473 vallen = ntohl(ep->vallen);
1475 || vallen > MAX_VALLEN)
1478 i = (vallen + 3) / 4;
1479 siglen = ntohl(ep->pkt[i++]);
1480 if ( siglen > MAX_VALLEN
1481 || len - VALUE_LEN < ((vallen + 3) / 4) * 4
1482 || len - VALUE_LEN - ((vallen + 3) / 4) * 4
1483 < ((siglen + 3) / 4) * 4)
1487 * Check for valid timestamp and filestamp. If the timestamp is
1488 * zero, the sender is not synchronized and signatures are
1489 * not possible. If nonzero the timestamp must not precede the
1490 * filestamp. The timestamp and filestamp must not precede the
1491 * corresponding values in the value structure, if present.
1493 tstamp = ntohl(ep->tstamp);
1494 fstamp = ntohl(ep->fstamp);
1498 if (tstamp < fstamp)
1502 tstamp1 = ntohl(vp->tstamp);
1503 fstamp1 = ntohl(vp->fstamp);
1504 if (tstamp1 != 0 && fstamp1 != 0) {
1505 if (tstamp < tstamp1)
1508 if ((tstamp < fstamp1 || fstamp < fstamp1))
1514 * At the time the certificate message is validated, the public
1515 * key in the message is not available. Thus, don't try to
1516 * verify the signature.
1518 if (opcode == (CRYPTO_CERT | CRYPTO_RESP))
1522 * Check for valid signature length, public key and digest
1525 if (crypto_flags & peer->crypto & CRYPTO_FLAG_PRIV)
1529 if (siglen == 0 || pkey == NULL || peer->digest == NULL)
1532 if (siglen != (u_int)EVP_PKEY_size(pkey))
1536 * Darn, I thought we would never get here. Verify the
1537 * signature. If the identity exchange is verified, light the
1538 * proventic bit. What a relief.
1540 ctx = EVP_MD_CTX_new();
1541 EVP_VerifyInit(ctx, peer->digest);
1542 /* XXX: the "+ 12" needs to be at least documented... */
1543 EVP_VerifyUpdate(ctx, (u_char *)&ep->tstamp, vallen + 12);
1544 if (EVP_VerifyFinal(ctx, (u_char *)&ep->pkt[i], siglen,
1546 EVP_MD_CTX_free(ctx);
1549 EVP_MD_CTX_free(ctx);
1551 if (peer->crypto & CRYPTO_FLAG_VRFY)
1552 peer->crypto |= CRYPTO_FLAG_PROV;
1558 * crypto_encrypt - construct vp (encrypted cookie and signature) from
1559 * the public key and cookie.
1563 * XEVNT_CKY bad or missing cookie
1564 * XEVNT_PUB bad or missing public key
1568 const u_char *ptr, /* Public Key */
1569 u_int vallen, /* Length of Public Key */
1570 keyid_t *cookie, /* server cookie */
1571 struct value *vp /* value pointer */
1574 EVP_PKEY *pkey; /* public key */
1575 EVP_MD_CTX *ctx; /* signature context */
1576 tstamp_t tstamp; /* NTP timestamp */
1581 * Extract the public key from the request.
1583 pkey = d2i_PublicKey(EVP_PKEY_RSA, NULL, &ptr, vallen);
1585 msyslog(LOG_ERR, "crypto_encrypt: %s",
1586 ERR_error_string(ERR_get_error(), NULL));
1591 * Encrypt the cookie, encode in ASN.1 and sign.
1593 memset(vp, 0, sizeof(struct value));
1594 tstamp = crypto_time();
1595 vp->tstamp = htonl(tstamp);
1596 vp->fstamp = hostval.tstamp;
1597 vallen = EVP_PKEY_size(pkey);
1598 vp->vallen = htonl(vallen);
1599 vp->ptr = emalloc(vallen);
1601 temp32 = htonl(*cookie);
1602 if (RSA_public_encrypt(4, (u_char *)&temp32, puch,
1603 EVP_PKEY_get0_RSA(pkey), RSA_PKCS1_OAEP_PADDING) <= 0) {
1604 msyslog(LOG_ERR, "crypto_encrypt: %s",
1605 ERR_error_string(ERR_get_error(), NULL));
1607 EVP_PKEY_free(pkey);
1610 EVP_PKEY_free(pkey);
1614 vp->sig = emalloc(sign_siglen);
1615 ctx = EVP_MD_CTX_new();
1616 EVP_SignInit(ctx, sign_digest);
1617 EVP_SignUpdate(ctx, (u_char *)&vp->tstamp, 12);
1618 EVP_SignUpdate(ctx, vp->ptr, vallen);
1619 if (EVP_SignFinal(ctx, vp->sig, &vallen, sign_pkey)) {
1620 INSIST(vallen <= sign_siglen);
1621 vp->siglen = htonl(vallen);
1623 EVP_MD_CTX_free(ctx);
1629 * crypto_ident - construct extension field for identity scheme
1631 * This routine determines which identity scheme is in use and
1632 * constructs an extension field for that scheme.
1635 * CRYTPO_IFF IFF scheme
1636 * CRYPTO_GQ GQ scheme
1637 * CRYPTO_MV MV scheme
1638 * CRYPTO_NULL no available scheme
1642 struct peer *peer /* peer structure pointer */
1645 char filename[MAXFILENAME];
1646 const char * scheme_name;
1650 * We come here after the group trusted host has been found; its
1651 * name defines the group name. Search the key cache for all
1652 * keys matching the same group name in order IFF, GQ and MV.
1653 * Use the first one available.
1656 if (peer->crypto & CRYPTO_FLAG_IFF) {
1657 scheme_name = "iff";
1658 scheme_id = CRYPTO_IFF;
1659 } else if (peer->crypto & CRYPTO_FLAG_GQ) {
1661 scheme_id = CRYPTO_GQ;
1662 } else if (peer->crypto & CRYPTO_FLAG_MV) {
1664 scheme_id = CRYPTO_MV;
1667 if (scheme_name != NULL) {
1668 snprintf(filename, sizeof(filename), "ntpkey_%spar_%s",
1669 scheme_name, peer->ident);
1670 peer->ident_pkey = crypto_key(filename, NULL,
1672 if (peer->ident_pkey != NULL)
1677 "crypto_ident: no identity parameters found for group %s",
1685 * crypto_args - construct extension field from arguments
1687 * This routine creates an extension field with current timestamps and
1688 * specified opcode, association ID and optional string. Note that the
1689 * extension field is created here, but freed after the crypto_xmit()
1690 * call in the protocol module.
1692 * Returns extension field pointer (no errors)
1694 * XXX: opcode and len should really be 32-bit quantities and
1695 * we should make sure that str is not too big.
1699 struct peer *peer, /* peer structure pointer */
1700 u_int opcode, /* operation code */
1701 associd_t associd, /* association ID */
1702 char *str /* argument string */
1705 tstamp_t tstamp; /* NTP timestamp */
1706 struct exten *ep; /* extension field pointer */
1707 u_int len; /* extension field length */
1710 tstamp = crypto_time();
1711 len = sizeof(struct exten);
1714 INSIST(slen < MAX_VALLEN);
1717 ep = emalloc_zero(len);
1721 REQUIRE(0 == (len & ~0x0000ffff));
1722 REQUIRE(0 == (opcode & ~0xffff0000));
1724 ep->opcode = htonl(opcode + len);
1725 ep->associd = htonl(associd);
1726 ep->tstamp = htonl(tstamp);
1727 ep->fstamp = hostval.tstamp;
1730 ep->vallen = htonl(slen);
1731 memcpy((char *)ep->pkt, str, slen);
1738 * crypto_send - construct extension field from value components
1740 * The value and signature fields are zero-padded to a word boundary.
1741 * Note: it is not polite to send a nonempty signature with zero
1742 * timestamp or a nonzero timestamp with an empty signature, but those
1743 * rules are not enforced here.
1745 * XXX This code won't work on a box with 16-bit ints.
1749 struct exten *ep, /* extension field pointer */
1750 struct value *vp, /* value pointer */
1751 int start /* buffer offset */
1754 u_int len, vallen, siglen, opcode;
1758 * Calculate extension field length and check for buffer
1759 * overflow. Leave room for the MAC.
1761 len = 16; /* XXX Document! */
1762 vallen = ntohl(vp->vallen);
1763 INSIST(vallen <= MAX_VALLEN);
1764 len += ((vallen + 3) / 4 + 1) * 4;
1765 siglen = ntohl(vp->siglen);
1766 len += ((siglen + 3) / 4 + 1) * 4;
1767 if (start + len > sizeof(struct pkt) - MAX_MAC_LEN)
1773 ep->tstamp = vp->tstamp;
1774 ep->fstamp = vp->fstamp;
1775 ep->vallen = vp->vallen;
1778 * Copy value. If the data field is empty or zero length,
1779 * encode an empty value with length zero.
1782 if (vallen > 0 && vp->ptr != NULL) {
1785 ep->pkt[i + j++] = 0;
1786 memcpy(&ep->pkt[i], vp->ptr, vallen);
1791 * Copy signature. If the signature field is empty or zero
1792 * length, encode an empty signature with length zero.
1794 ep->pkt[i++] = vp->siglen;
1795 if (siglen > 0 && vp->sig != NULL) {
1798 ep->pkt[i + j++] = 0;
1799 memcpy(&ep->pkt[i], vp->sig, siglen);
1800 /* i += j; */ /* We don't use i after this */
1802 opcode = ntohl(ep->opcode);
1803 ep->opcode = htonl((opcode & 0xffff0000) | len);
1804 ENSURE(len <= MAX_VALLEN);
1810 * crypto_update - compute new public value and sign extension fields
1812 * This routine runs periodically, like once a day, and when something
1813 * changes. It updates the timestamps on three value structures and one
1814 * value structure list, then signs all the structures:
1816 * hostval host name (not signed)
1818 * cinfo certificate info/value list
1819 * tai_leap leap values
1821 * Filestamps are proventic data, so this routine runs only when the
1822 * host is synchronized to a proventicated source. Thus, the timestamp
1823 * is proventic and can be used to deflect clogging attacks.
1825 * Returns void (no errors)
1830 EVP_MD_CTX *ctx; /* message digest context */
1831 struct cert_info *cp; /* certificate info/value */
1832 char statstr[NTP_MAXSTRLEN]; /* statistics for filegen */
1835 leap_result_t leap_data;
1837 hostval.tstamp = htonl(crypto_time());
1838 if (hostval.tstamp == 0)
1841 ctx = EVP_MD_CTX_new();
1844 * Sign public key and timestamps. The filestamp is derived from
1845 * the host key file extension from wherever the file was
1848 if (pubkey.vallen != 0) {
1849 pubkey.tstamp = hostval.tstamp;
1851 if (pubkey.sig == NULL)
1852 pubkey.sig = emalloc(sign_siglen);
1853 EVP_SignInit(ctx, sign_digest);
1854 EVP_SignUpdate(ctx, (u_char *)&pubkey, 12);
1855 EVP_SignUpdate(ctx, pubkey.ptr, ntohl(pubkey.vallen));
1856 if (EVP_SignFinal(ctx, pubkey.sig, &len, sign_pkey)) {
1857 INSIST(len <= sign_siglen);
1858 pubkey.siglen = htonl(len);
1863 * Sign certificates and timestamps. The filestamp is derived
1864 * from the certificate file extension from wherever the file
1865 * was generated. Note we do not throw expired certificates
1866 * away; they may have signed younger ones.
1868 for (cp = cinfo; cp != NULL; cp = cp->link) {
1869 cp->cert.tstamp = hostval.tstamp;
1870 cp->cert.siglen = 0;
1871 if (cp->cert.sig == NULL)
1872 cp->cert.sig = emalloc(sign_siglen);
1873 EVP_SignInit(ctx, sign_digest);
1874 EVP_SignUpdate(ctx, (u_char *)&cp->cert, 12);
1875 EVP_SignUpdate(ctx, cp->cert.ptr,
1876 ntohl(cp->cert.vallen));
1877 if (EVP_SignFinal(ctx, cp->cert.sig, &len, sign_pkey)) {
1878 INSIST(len <= sign_siglen);
1879 cp->cert.siglen = htonl(len);
1884 * Sign leapseconds values and timestamps. Note it is not an
1885 * error to return null values.
1887 tai_leap.tstamp = hostval.tstamp;
1888 tai_leap.fstamp = hostval.fstamp;
1890 /* Get the leap second era. We might need a full lookup early
1891 * after start, when the cache is not yet loaded.
1893 leapsec_frame(&leap_data);
1894 if ( ! memcmp(&leap_data.ebase, &leap_data.ttime, sizeof(vint64))) {
1895 time_t now = time(NULL);
1896 uint32_t nowntp = (uint32_t)now + JAN_1970;
1897 leapsec_query(&leap_data, nowntp, &now);
1900 /* Create the data block. The protocol does not work without. */
1901 len = 3 * sizeof(u_int32);
1902 if (tai_leap.ptr == NULL || ntohl(tai_leap.vallen) != len) {
1904 tai_leap.ptr = emalloc(len);
1905 tai_leap.vallen = htonl(len);
1907 ptr = (u_int32 *)tai_leap.ptr;
1908 if (leap_data.tai_offs > 10) {
1909 /* create a TAI / leap era block. The end time is a
1910 * fake -- maybe we can do better.
1912 ptr[0] = htonl(leap_data.tai_offs);
1913 ptr[1] = htonl(leap_data.ebase.d_s.lo);
1914 if (leap_data.ttime.d_s.hi >= 0)
1915 ptr[2] = htonl(leap_data.ttime.D_s.lo + 7*86400);
1917 ptr[2] = htonl(leap_data.ebase.D_s.lo + 25*86400);
1919 /* no leap era available */
1920 memset(ptr, 0, len);
1922 if (tai_leap.sig == NULL)
1923 tai_leap.sig = emalloc(sign_siglen);
1924 EVP_SignInit(ctx, sign_digest);
1925 EVP_SignUpdate(ctx, (u_char *)&tai_leap, 12);
1926 EVP_SignUpdate(ctx, tai_leap.ptr, len);
1927 if (EVP_SignFinal(ctx, tai_leap.sig, &len, sign_pkey)) {
1928 INSIST(len <= sign_siglen);
1929 tai_leap.siglen = htonl(len);
1931 crypto_flags |= CRYPTO_FLAG_TAI;
1933 snprintf(statstr, sizeof(statstr), "signature update ts %u",
1934 ntohl(hostval.tstamp));
1935 record_crypto_stats(NULL, statstr);
1936 DPRINTF(1, ("crypto_update: %s\n", statstr));
1937 EVP_MD_CTX_free(ctx);
1941 * crypto_update_taichange - eventually trigger crypto_update
1943 * This is called when a change in 'sys_tai' is detected. This will
1944 * happen shortly after a leap second is detected, but unhappily also
1945 * early after system start; also, the crypto stuff might be unused and
1946 * an unguarded call to crypto_update() causes a crash.
1948 * This function makes sure that there already *is* a valid crypto block
1949 * for the use with autokey, and only calls 'crypto_update()' if it can
1952 * Returns void (no errors)
1955 crypto_update_taichange(void)
1957 static const u_int len = 3 * sizeof(u_int32);
1959 /* check if the signing digest algo is available */
1960 if (sign_digest == NULL || sign_pkey == NULL)
1963 /* check size of TAI extension block */
1964 if (tai_leap.ptr == NULL || ntohl(tai_leap.vallen) != len)
1967 /* crypto_update should at least not crash here! */
1972 * value_free - free value structure components.
1974 * Returns void (no errors)
1978 struct value *vp /* value structure */
1981 if (vp->ptr != NULL)
1983 if (vp->sig != NULL)
1985 memset(vp, 0, sizeof(struct value));
1990 * crypto_time - returns current NTP time.
1992 * Returns NTP seconds if in synch, 0 otherwise
1997 l_fp tstamp; /* NTP time */
2000 if (sys_leap != LEAP_NOTINSYNC)
2001 get_systime(&tstamp);
2002 return (tstamp.l_ui);
2007 * asn_to_calendar - convert ASN1_TIME time structure to struct calendar.
2013 ASN1_TIME *asn1time, /* pointer to ASN1_TIME structure */
2014 struct calendar *pjd /* pointer to result */
2017 size_t len; /* length of ASN1_TIME string */
2018 char v[24]; /* writable copy of ASN1_TIME string */
2019 unsigned long temp; /* result from strtoul */
2022 * Extract time string YYMMDDHHMMSSZ from ASN1 time structure.
2023 * Or YYYYMMDDHHMMSSZ.
2024 * Note that the YY, MM, DD fields start with one, the HH, MM,
2025 * SS fields start with zero and the Z character is ignored.
2026 * Also note that two-digit years less than 50 map to years greater than
2027 * 100. Dontcha love ASN.1? Better than MIL-188.
2029 len = asn1time->length;
2030 REQUIRE(len < sizeof(v));
2031 (void)strncpy(v, (char *)(asn1time->data), len);
2033 temp = strtoul(v+len-3, NULL, 10);
2037 temp = strtoul(v+len-5, NULL, 10);
2041 temp = strtoul(v+len-7, NULL, 10);
2045 temp = strtoul(v+len-9, NULL, 10);
2046 pjd->monthday = temp;
2049 temp = strtoul(v+len-11, NULL, 10);
2053 temp = strtoul(v, NULL, 10);
2054 /* handle two-digit years */
2061 pjd->yearday = pjd->weekday = 0;
2067 * bigdig() - compute a BIGNUM MD5 hash of a BIGNUM number.
2069 * Returns void (no errors)
2073 BIGNUM *bn, /* BIGNUM * from */
2074 BIGNUM *bk /* BIGNUM * to */
2077 EVP_MD_CTX *ctx; /* message digest context */
2078 u_char dgst[EVP_MAX_MD_SIZE]; /* message digest */
2079 u_char *ptr; /* a BIGNUM as binary string */
2082 len = BN_num_bytes(bn);
2085 ctx = EVP_MD_CTX_new();
2086 EVP_DigestInit(ctx, EVP_md5());
2087 EVP_DigestUpdate(ctx, ptr, len);
2088 EVP_DigestFinal(ctx, dgst, &len);
2089 EVP_MD_CTX_free(ctx);
2090 BN_bin2bn(dgst, len, bk);
2096 ***********************************************************************
2098 * The following routines implement the Schnorr (IFF) identity scheme *
2100 ***********************************************************************
2102 * The Schnorr (IFF) identity scheme is intended for use when
2103 * certificates are generated by some other trusted certificate
2104 * authority and the certificate cannot be used to convey public
2105 * parameters. There are two kinds of files: encrypted server files that
2106 * contain private and public values and nonencrypted client files that
2107 * contain only public values. New generations of server files must be
2108 * securely transmitted to all servers of the group; client files can be
2109 * distributed by any means. The scheme is self contained and
2110 * independent of new generations of host keys, sign keys and
2113 * The IFF values hide in a DSA cuckoo structure which uses the same
2114 * parameters. The values are used by an identity scheme based on DSA
2115 * cryptography and described in Stimson p. 285. The p is a 512-bit
2116 * prime, g a generator of Zp* and q a 160-bit prime that divides p - 1
2117 * and is a qth root of 1 mod p; that is, g^q = 1 mod p. The TA rolls a
2118 * private random group key b (0 < b < q) and public key v = g^b, then
2119 * sends (p, q, g, b) to the servers and (p, q, g, v) to the clients.
2120 * Alice challenges Bob to confirm identity using the protocol described
2125 * The scheme goes like this. Both Alice and Bob have the public primes
2126 * p, q and generator g. The TA gives private key b to Bob and public
2129 * Alice rolls new random challenge r (o < r < q) and sends to Bob in
2130 * the IFF request message. Bob rolls new random k (0 < k < q), then
2131 * computes y = k + b r mod q and x = g^k mod p and sends (y, hash(x))
2132 * to Alice in the response message. Besides making the response
2133 * shorter, the hash makes it effectivey impossible for an intruder to
2134 * solve for b by observing a number of these messages.
2136 * Alice receives the response and computes g^y v^r mod p. After a bit
2137 * of algebra, this simplifies to g^k. If the hash of this result
2138 * matches hash(x), Alice knows that Bob has the group key b. The signed
2139 * response binds this knowledge to Bob's private key and the public key
2140 * previously received in his certificate.
2142 * crypto_alice - construct Alice's challenge in IFF scheme
2146 * XEVNT_ID bad or missing group key
2147 * XEVNT_PUB bad or missing public key
2151 struct peer *peer, /* peer pointer */
2152 struct value *vp /* value pointer */
2155 DSA *dsa; /* IFF parameters */
2156 BN_CTX *bctx; /* BIGNUM context */
2157 EVP_MD_CTX *ctx; /* signature context */
2163 * The identity parameters must have correct format and content.
2165 if (peer->ident_pkey == NULL) {
2166 msyslog(LOG_NOTICE, "crypto_alice: scheme unavailable");
2170 if ((dsa = EVP_PKEY_get0_DSA(peer->ident_pkey->pkey)) == NULL) {
2171 msyslog(LOG_NOTICE, "crypto_alice: defective key");
2176 * Roll new random r (0 < r < q).
2178 if (peer->iffval != NULL)
2179 BN_free(peer->iffval);
2180 peer->iffval = BN_new();
2181 DSA_get0_pqg(dsa, NULL, &q, NULL);
2182 len = BN_num_bytes(q);
2183 BN_rand(peer->iffval, len * 8, -1, 1); /* r mod q*/
2184 bctx = BN_CTX_new();
2185 BN_mod(peer->iffval, peer->iffval, q, bctx);
2189 * Sign and send to Bob. The filestamp is from the local file.
2191 memset(vp, 0, sizeof(struct value));
2192 tstamp = crypto_time();
2193 vp->tstamp = htonl(tstamp);
2194 vp->fstamp = htonl(peer->ident_pkey->fstamp);
2195 vp->vallen = htonl(len);
2196 vp->ptr = emalloc(len);
2197 BN_bn2bin(peer->iffval, vp->ptr);
2201 vp->sig = emalloc(sign_siglen);
2202 ctx = EVP_MD_CTX_new();
2203 EVP_SignInit(ctx, sign_digest);
2204 EVP_SignUpdate(ctx, (u_char *)&vp->tstamp, 12);
2205 EVP_SignUpdate(ctx, vp->ptr, len);
2206 if (EVP_SignFinal(ctx, vp->sig, &len, sign_pkey)) {
2207 INSIST(len <= sign_siglen);
2208 vp->siglen = htonl(len);
2210 EVP_MD_CTX_free(ctx);
2216 * crypto_bob - construct Bob's response to Alice's challenge
2220 * XEVNT_ERR protocol error
2221 * XEVNT_ID bad or missing group key
2225 struct exten *ep, /* extension pointer */
2226 struct value *vp /* value pointer */
2229 DSA *dsa; /* IFF parameters */
2230 DSA_SIG *sdsa; /* DSA signature context fake */
2231 BN_CTX *bctx; /* BIGNUM context */
2232 EVP_MD_CTX *ctx; /* signature context */
2233 tstamp_t tstamp; /* NTP timestamp */
2234 BIGNUM *bn, *bk, *r;
2236 u_int len; /* extension field value length */
2237 const BIGNUM *p, *q, *g;
2238 const BIGNUM *priv_key;
2241 * If the IFF parameters are not valid, something awful
2242 * happened or we are being tormented.
2244 if (iffkey_info == NULL) {
2245 msyslog(LOG_NOTICE, "crypto_bob: scheme unavailable");
2248 dsa = EVP_PKEY_get0_DSA(iffkey_info->pkey);
2249 DSA_get0_pqg(dsa, &p, &q, &g);
2250 DSA_get0_key(dsa, NULL, &priv_key);
2253 * Extract r from the challenge.
2255 len = exten_payload_size(ep);
2256 if (len == 0 || len > MAX_VALLEN)
2258 if ((r = BN_bin2bn((u_char *)ep->pkt, len, NULL)) == NULL) {
2259 msyslog(LOG_ERR, "crypto_bob: %s",
2260 ERR_error_string(ERR_get_error(), NULL));
2265 * Bob rolls random k (0 < k < q), computes y = k + b r mod q
2266 * and x = g^k mod p, then sends (y, hash(x)) to Alice.
2268 bctx = BN_CTX_new(); bk = BN_new(); bn = BN_new();
2269 sdsa = DSA_SIG_new();
2270 BN_rand(bk, len * 8, -1, 1); /* k */
2271 BN_mod_mul(bn, priv_key, r, q, bctx); /* b r mod q */
2273 BN_mod(bn, bn, q, bctx); /* k + b r mod q */
2274 BN_mod_exp(bk, g, bk, p, bctx); /* g^k mod p */
2276 DSA_SIG_set0(sdsa, bn, bk);
2281 DSA_print_fp(stdout, dsa, 0);
2285 * Encode the values in ASN.1 and sign. The filestamp is from
2288 len = i2d_DSA_SIG(sdsa, NULL);
2290 msyslog(LOG_ERR, "crypto_bob: %s",
2291 ERR_error_string(ERR_get_error(), NULL));
2295 if (len > MAX_VALLEN) {
2296 msyslog(LOG_ERR, "crypto_bob: signature is too big: %u",
2301 memset(vp, 0, sizeof(struct value));
2302 tstamp = crypto_time();
2303 vp->tstamp = htonl(tstamp);
2304 vp->fstamp = htonl(iffkey_info->fstamp);
2305 vp->vallen = htonl(len);
2308 i2d_DSA_SIG(sdsa, &ptr);
2313 /* XXX: more validation to make sure the sign fits... */
2314 vp->sig = emalloc(sign_siglen);
2315 ctx = EVP_MD_CTX_new();
2316 EVP_SignInit(ctx, sign_digest);
2317 EVP_SignUpdate(ctx, (u_char *)&vp->tstamp, 12);
2318 EVP_SignUpdate(ctx, vp->ptr, len);
2319 if (EVP_SignFinal(ctx, vp->sig, &len, sign_pkey)) {
2320 INSIST(len <= sign_siglen);
2321 vp->siglen = htonl(len);
2323 EVP_MD_CTX_free(ctx);
2329 * crypto_iff - verify Bob's response to Alice's challenge
2333 * XEVNT_FSP bad filestamp
2334 * XEVNT_ID bad or missing group key
2335 * XEVNT_PUB bad or missing public key
2339 struct exten *ep, /* extension pointer */
2340 struct peer *peer /* peer structure pointer */
2343 DSA *dsa; /* IFF parameters */
2344 BN_CTX *bctx; /* BIGNUM context */
2345 DSA_SIG *sdsa; /* DSA parameters */
2350 const BIGNUM *p, *g;
2351 const BIGNUM *r, *s;
2352 const BIGNUM *pub_key;
2355 * If the IFF parameters are not valid or no challenge was sent,
2356 * something awful happened or we are being tormented.
2358 if (peer->ident_pkey == NULL) {
2359 msyslog(LOG_NOTICE, "crypto_iff: scheme unavailable");
2362 if (ntohl(ep->fstamp) != peer->ident_pkey->fstamp) {
2363 msyslog(LOG_NOTICE, "crypto_iff: invalid filestamp %u",
2367 if ((dsa = EVP_PKEY_get0_DSA(peer->ident_pkey->pkey)) == NULL) {
2368 msyslog(LOG_NOTICE, "crypto_iff: defective key");
2371 if (peer->iffval == NULL) {
2372 msyslog(LOG_NOTICE, "crypto_iff: missing challenge");
2377 * Extract the k + b r and g^k values from the response.
2379 bctx = BN_CTX_new(); bk = BN_new(); bn = BN_new();
2380 len = ntohl(ep->vallen);
2381 ptr = (u_char *)ep->pkt;
2382 if ((sdsa = d2i_DSA_SIG(NULL, &ptr, len)) == NULL) {
2383 BN_free(bn); BN_free(bk); BN_CTX_free(bctx);
2384 msyslog(LOG_ERR, "crypto_iff: %s",
2385 ERR_error_string(ERR_get_error(), NULL));
2390 * Compute g^(k + b r) g^(q - b)r mod p.
2392 DSA_get0_key(dsa, &pub_key, NULL);
2393 DSA_get0_pqg(dsa, &p, NULL, &g);
2394 DSA_SIG_get0(sdsa, &r, &s);
2395 BN_mod_exp(bn, pub_key, peer->iffval, p, bctx);
2396 BN_mod_exp(bk, g, r, p, bctx);
2397 BN_mod_mul(bn, bn, bk, p, bctx);
2400 * Verify the hash of the result matches hash(x).
2403 temp = BN_cmp(bn, s);
2404 BN_free(bn); BN_free(bk); BN_CTX_free(bctx);
2405 BN_free(peer->iffval);
2406 peer->iffval = NULL;
2411 msyslog(LOG_NOTICE, "crypto_iff: identity not verified");
2417 ***********************************************************************
2419 * The following routines implement the Guillou-Quisquater (GQ) *
2422 ***********************************************************************
2424 * The Guillou-Quisquater (GQ) identity scheme is intended for use when
2425 * the certificate can be used to convey public parameters. The scheme
2426 * uses a X509v3 certificate extension field do convey the public key of
2427 * a private key known only to servers. There are two kinds of files:
2428 * encrypted server files that contain private and public values and
2429 * nonencrypted client files that contain only public values. New
2430 * generations of server files must be securely transmitted to all
2431 * servers of the group; client files can be distributed by any means.
2432 * The scheme is self contained and independent of new generations of
2433 * host keys and sign keys. The scheme is self contained and independent
2434 * of new generations of host keys and sign keys.
2436 * The GQ parameters hide in a RSA cuckoo structure which uses the same
2437 * parameters. The values are used by an identity scheme based on RSA
2438 * cryptography and described in Stimson p. 300 (with errors). The 512-
2439 * bit public modulus is n = p q, where p and q are secret large primes.
2440 * The TA rolls private random group key b as RSA exponent. These values
2441 * are known to all group members.
2443 * When rolling new certificates, a server recomputes the private and
2444 * public keys. The private key u is a random roll, while the public key
2445 * is the inverse obscured by the group key v = (u^-1)^b. These values
2446 * replace the private and public keys normally generated by the RSA
2447 * scheme. Alice challenges Bob to confirm identity using the protocol
2452 * The scheme goes like this. Both Alice and Bob have the same modulus n
2453 * and some random b as the group key. These values are computed and
2454 * distributed in advance via secret means, although only the group key
2455 * b is truly secret. Each has a private random private key u and public
2456 * key (u^-1)^b, although not necessarily the same ones. Bob and Alice
2457 * can regenerate the key pair from time to time without affecting
2458 * operations. The public key is conveyed on the certificate in an
2459 * extension field; the private key is never revealed.
2461 * Alice rolls new random challenge r and sends to Bob in the GQ
2462 * request message. Bob rolls new random k, then computes y = k u^r mod
2463 * n and x = k^b mod n and sends (y, hash(x)) to Alice in the response
2464 * message. Besides making the response shorter, the hash makes it
2465 * effectivey impossible for an intruder to solve for b by observing
2466 * a number of these messages.
2468 * Alice receives the response and computes y^b v^r mod n. After a bit
2469 * of algebra, this simplifies to k^b. If the hash of this result
2470 * matches hash(x), Alice knows that Bob has the group key b. The signed
2471 * response binds this knowledge to Bob's private key and the public key
2472 * previously received in his certificate.
2474 * crypto_alice2 - construct Alice's challenge in GQ scheme
2478 * XEVNT_ID bad or missing group key
2479 * XEVNT_PUB bad or missing public key
2483 struct peer *peer, /* peer pointer */
2484 struct value *vp /* value pointer */
2487 RSA *rsa; /* GQ parameters */
2488 BN_CTX *bctx; /* BIGNUM context */
2489 EVP_MD_CTX *ctx; /* signature context */
2495 * The identity parameters must have correct format and content.
2497 if (peer->ident_pkey == NULL)
2500 if ((rsa = EVP_PKEY_get0_RSA(peer->ident_pkey->pkey)) == NULL) {
2501 msyslog(LOG_NOTICE, "crypto_alice2: defective key");
2506 * Roll new random r (0 < r < n).
2508 if (peer->iffval != NULL)
2509 BN_free(peer->iffval);
2510 peer->iffval = BN_new();
2511 RSA_get0_key(rsa, &n, NULL, NULL);
2512 len = BN_num_bytes(n);
2513 BN_rand(peer->iffval, len * 8, -1, 1); /* r mod n */
2514 bctx = BN_CTX_new();
2515 BN_mod(peer->iffval, peer->iffval, n, bctx);
2519 * Sign and send to Bob. The filestamp is from the local file.
2521 memset(vp, 0, sizeof(struct value));
2522 tstamp = crypto_time();
2523 vp->tstamp = htonl(tstamp);
2524 vp->fstamp = htonl(peer->ident_pkey->fstamp);
2525 vp->vallen = htonl(len);
2526 vp->ptr = emalloc(len);
2527 BN_bn2bin(peer->iffval, vp->ptr);
2531 vp->sig = emalloc(sign_siglen);
2532 ctx = EVP_MD_CTX_new();
2533 EVP_SignInit(ctx, sign_digest);
2534 EVP_SignUpdate(ctx, (u_char *)&vp->tstamp, 12);
2535 EVP_SignUpdate(ctx, vp->ptr, len);
2536 if (EVP_SignFinal(ctx, vp->sig, &len, sign_pkey)) {
2537 INSIST(len <= sign_siglen);
2538 vp->siglen = htonl(len);
2540 EVP_MD_CTX_free(ctx);
2546 * crypto_bob2 - construct Bob's response to Alice's challenge
2550 * XEVNT_ERR protocol error
2551 * XEVNT_ID bad or missing group key
2555 struct exten *ep, /* extension pointer */
2556 struct value *vp /* value pointer */
2559 RSA *rsa; /* GQ parameters */
2560 DSA_SIG *sdsa; /* DSA parameters */
2561 BN_CTX *bctx; /* BIGNUM context */
2562 EVP_MD_CTX *ctx; /* signature context */
2563 tstamp_t tstamp; /* NTP timestamp */
2564 BIGNUM *r, *k, *g, *y;
2568 const BIGNUM *n, *p, *e;
2571 * If the GQ parameters are not valid, something awful
2572 * happened or we are being tormented.
2574 if (gqkey_info == NULL) {
2575 msyslog(LOG_NOTICE, "crypto_bob2: scheme unavailable");
2578 rsa = EVP_PKEY_get0_RSA(gqkey_info->pkey);
2579 RSA_get0_key(rsa, &n, &p, &e);
2582 * Extract r from the challenge.
2584 len = exten_payload_size(ep);
2585 if (len == 0 || len > MAX_VALLEN)
2587 if ((r = BN_bin2bn((u_char *)ep->pkt, len, NULL)) == NULL) {
2588 msyslog(LOG_ERR, "crypto_bob2: %s",
2589 ERR_error_string(ERR_get_error(), NULL));
2594 * Bob rolls random k (0 < k < n), computes y = k u^r mod n and
2595 * x = k^b mod n, then sends (y, hash(x)) to Alice.
2597 bctx = BN_CTX_new(); k = BN_new(); g = BN_new(); y = BN_new();
2598 sdsa = DSA_SIG_new();
2599 BN_rand(k, len * 8, -1, 1); /* k */
2600 BN_mod(k, k, n, bctx);
2601 BN_mod_exp(y, p, r, n, bctx); /* u^r mod n */
2602 BN_mod_mul(y, k, y, n, bctx); /* k u^r mod n */
2603 BN_mod_exp(g, k, e, n, bctx); /* k^b mod n */
2605 DSA_SIG_set0(sdsa, y, g);
2607 BN_free(r); BN_free(k);
2610 RSA_print_fp(stdout, rsa, 0);
2614 * Encode the values in ASN.1 and sign. The filestamp is from
2617 len = s_len = i2d_DSA_SIG(sdsa, NULL);
2619 msyslog(LOG_ERR, "crypto_bob2: %s",
2620 ERR_error_string(ERR_get_error(), NULL));
2624 memset(vp, 0, sizeof(struct value));
2625 tstamp = crypto_time();
2626 vp->tstamp = htonl(tstamp);
2627 vp->fstamp = htonl(gqkey_info->fstamp);
2628 vp->vallen = htonl(len);
2631 i2d_DSA_SIG(sdsa, &ptr);
2636 vp->sig = emalloc(sign_siglen);
2637 ctx = EVP_MD_CTX_new();
2638 EVP_SignInit(ctx, sign_digest);
2639 EVP_SignUpdate(ctx, (u_char *)&vp->tstamp, 12);
2640 EVP_SignUpdate(ctx, vp->ptr, len);
2641 if (EVP_SignFinal(ctx, vp->sig, &len, sign_pkey)) {
2642 INSIST(len <= sign_siglen);
2643 vp->siglen = htonl(len);
2645 EVP_MD_CTX_free(ctx);
2651 * crypto_gq - verify Bob's response to Alice's challenge
2655 * XEVNT_ERR protocol error
2656 * XEVNT_FSP bad filestamp
2657 * XEVNT_ID bad or missing group keys
2658 * XEVNT_PUB bad or missing public key
2662 struct exten *ep, /* extension pointer */
2663 struct peer *peer /* peer structure pointer */
2666 RSA *rsa; /* GQ parameters */
2667 BN_CTX *bctx; /* BIGNUM context */
2668 DSA_SIG *sdsa; /* RSA signature context fake */
2673 const BIGNUM *n, *e;
2674 const BIGNUM *r, *s;
2677 * If the GQ parameters are not valid or no challenge was sent,
2678 * something awful happened or we are being tormented. Note that
2679 * the filestamp on the local key file can be greater than on
2680 * the remote parameter file if the keys have been refreshed.
2682 if (peer->ident_pkey == NULL) {
2683 msyslog(LOG_NOTICE, "crypto_gq: scheme unavailable");
2686 if (ntohl(ep->fstamp) < peer->ident_pkey->fstamp) {
2687 msyslog(LOG_NOTICE, "crypto_gq: invalid filestamp %u",
2691 if ((rsa = EVP_PKEY_get0_RSA(peer->ident_pkey->pkey)) == NULL) {
2692 msyslog(LOG_NOTICE, "crypto_gq: defective key");
2695 RSA_get0_key(rsa, &n, NULL, &e);
2696 if (peer->iffval == NULL) {
2697 msyslog(LOG_NOTICE, "crypto_gq: missing challenge");
2702 * Extract the y = k u^r and hash(x = k^b) values from the
2705 bctx = BN_CTX_new(); y = BN_new(); v = BN_new();
2706 len = ntohl(ep->vallen);
2707 ptr = (u_char *)ep->pkt;
2708 if ((sdsa = d2i_DSA_SIG(NULL, &ptr, len)) == NULL) {
2709 BN_CTX_free(bctx); BN_free(y); BN_free(v);
2710 msyslog(LOG_ERR, "crypto_gq: %s",
2711 ERR_error_string(ERR_get_error(), NULL));
2714 DSA_SIG_get0(sdsa, &r, &s);
2717 * Compute v^r y^b mod n.
2719 if (peer->grpkey == NULL) {
2720 msyslog(LOG_NOTICE, "crypto_gq: missing group key");
2723 BN_mod_exp(v, peer->grpkey, peer->iffval, n, bctx);
2725 BN_mod_exp(y, r, e, n, bctx); /* y^b mod n */
2726 BN_mod_mul(y, v, y, n, bctx); /* v^r y^b mod n */
2729 * Verify the hash of the result matches hash(x).
2732 temp = BN_cmp(y, s);
2733 BN_CTX_free(bctx); BN_free(y); BN_free(v);
2734 BN_free(peer->iffval);
2735 peer->iffval = NULL;
2740 msyslog(LOG_NOTICE, "crypto_gq: identity not verified");
2746 ***********************************************************************
2748 * The following routines implement the Mu-Varadharajan (MV) identity *
2751 ***********************************************************************
2753 * The Mu-Varadharajan (MV) cryptosystem was originally intended when
2754 * servers broadcast messages to clients, but clients never send
2755 * messages to servers. There is one encryption key for the server and a
2756 * separate decryption key for each client. It operated something like a
2757 * pay-per-view satellite broadcasting system where the session key is
2758 * encrypted by the broadcaster and the decryption keys are held in a
2759 * tamperproof set-top box.
2761 * The MV parameters and private encryption key hide in a DSA cuckoo
2762 * structure which uses the same parameters, but generated in a
2763 * different way. The values are used in an encryption scheme similar to
2764 * El Gamal cryptography and a polynomial formed from the expansion of
2765 * product terms (x - x[j]), as described in Mu, Y., and V.
2766 * Varadharajan: Robust and Secure Broadcasting, Proc. Indocrypt 2001,
2767 * 223-231. The paper has significant errors and serious omissions.
2769 * Let q be the product of n distinct primes s1[j] (j = 1...n), where
2770 * each s1[j] has m significant bits. Let p be a prime p = 2 * q + 1, so
2771 * that q and each s1[j] divide p - 1 and p has M = n * m + 1
2772 * significant bits. Let g be a generator of Zp; that is, gcd(g, p - 1)
2773 * = 1 and g^q = 1 mod p. We do modular arithmetic over Zq and then
2774 * project into Zp* as exponents of g. Sometimes we have to compute an
2775 * inverse b^-1 of random b in Zq, but for that purpose we require
2776 * gcd(b, q) = 1. We expect M to be in the 500-bit range and n
2777 * relatively small, like 30. These are the parameters of the scheme and
2778 * they are expensive to compute.
2780 * We set up an instance of the scheme as follows. A set of random
2781 * values x[j] mod q (j = 1...n), are generated as the zeros of a
2782 * polynomial of order n. The product terms (x - x[j]) are expanded to
2783 * form coefficients a[i] mod q (i = 0...n) in powers of x. These are
2784 * used as exponents of the generator g mod p to generate the private
2785 * encryption key A. The pair (gbar, ghat) of public server keys and the
2786 * pairs (xbar[j], xhat[j]) (j = 1...n) of private client keys are used
2787 * to construct the decryption keys. The devil is in the details.
2789 * This routine generates a private server encryption file including the
2790 * private encryption key E and partial decryption keys gbar and ghat.
2791 * It then generates public client decryption files including the public
2792 * keys xbar[j] and xhat[j] for each client j. The partial decryption
2793 * files are used to compute the inverse of E. These values are suitably
2794 * blinded so secrets are not revealed.
2796 * The distinguishing characteristic of this scheme is the capability to
2797 * revoke keys. Included in the calculation of E, gbar and ghat is the
2798 * product s = prod(s1[j]) (j = 1...n) above. If the factor s1[j] is
2799 * subsequently removed from the product and E, gbar and ghat
2800 * recomputed, the jth client will no longer be able to compute E^-1 and
2801 * thus unable to decrypt the messageblock.
2805 * The scheme goes like this. Bob has the server values (p, E, q, gbar,
2806 * ghat) and Alice has the client values (p, xbar, xhat).
2808 * Alice rolls new random nonce r mod p and sends to Bob in the MV
2809 * request message. Bob rolls random nonce k mod q, encrypts y = r E^k
2810 * mod p and sends (y, gbar^k, ghat^k) to Alice.
2812 * Alice receives the response and computes the inverse (E^k)^-1 from
2813 * the partial decryption keys gbar^k, ghat^k, xbar and xhat. She then
2814 * decrypts y and verifies it matches the original r. The signed
2815 * response binds this knowledge to Bob's private key and the public key
2816 * previously received in his certificate.
2818 * crypto_alice3 - construct Alice's challenge in MV scheme
2822 * XEVNT_ID bad or missing group key
2823 * XEVNT_PUB bad or missing public key
2827 struct peer *peer, /* peer pointer */
2828 struct value *vp /* value pointer */
2831 DSA *dsa; /* MV parameters */
2832 BN_CTX *bctx; /* BIGNUM context */
2833 EVP_MD_CTX *ctx; /* signature context */
2839 * The identity parameters must have correct format and content.
2841 if (peer->ident_pkey == NULL)
2844 if ((dsa = EVP_PKEY_get0_DSA(peer->ident_pkey->pkey)) == NULL) {
2845 msyslog(LOG_NOTICE, "crypto_alice3: defective key");
2848 DSA_get0_pqg(dsa, &p, NULL, NULL);
2851 * Roll new random r (0 < r < q).
2853 if (peer->iffval != NULL)
2854 BN_free(peer->iffval);
2855 peer->iffval = BN_new();
2856 len = BN_num_bytes(p);
2857 BN_rand(peer->iffval, len * 8, -1, 1); /* r mod p */
2858 bctx = BN_CTX_new();
2859 BN_mod(peer->iffval, peer->iffval, p, bctx);
2863 * Sign and send to Bob. The filestamp is from the local file.
2865 memset(vp, 0, sizeof(struct value));
2866 tstamp = crypto_time();
2867 vp->tstamp = htonl(tstamp);
2868 vp->fstamp = htonl(peer->ident_pkey->fstamp);
2869 vp->vallen = htonl(len);
2870 vp->ptr = emalloc(len);
2871 BN_bn2bin(peer->iffval, vp->ptr);
2875 vp->sig = emalloc(sign_siglen);
2876 ctx = EVP_MD_CTX_new();
2877 EVP_SignInit(ctx, sign_digest);
2878 EVP_SignUpdate(ctx, (u_char *)&vp->tstamp, 12);
2879 EVP_SignUpdate(ctx, vp->ptr, len);
2880 if (EVP_SignFinal(ctx, vp->sig, &len, sign_pkey)) {
2881 INSIST(len <= sign_siglen);
2882 vp->siglen = htonl(len);
2884 EVP_MD_CTX_free(ctx);
2890 * crypto_bob3 - construct Bob's response to Alice's challenge
2894 * XEVNT_ERR protocol error
2898 struct exten *ep, /* extension pointer */
2899 struct value *vp /* value pointer */
2902 DSA *dsa; /* MV parameters */
2903 DSA *sdsa; /* DSA signature context fake */
2904 BN_CTX *bctx; /* BIGNUM context */
2905 EVP_MD_CTX *ctx; /* signature context */
2906 tstamp_t tstamp; /* NTP timestamp */
2910 const BIGNUM *p, *q, *g;
2911 const BIGNUM *pub_key, *priv_key;
2912 BIGNUM *sp, *sq, *sg;
2915 * If the MV parameters are not valid, something awful
2916 * happened or we are being tormented.
2918 if (mvkey_info == NULL) {
2919 msyslog(LOG_NOTICE, "crypto_bob3: scheme unavailable");
2922 dsa = EVP_PKEY_get0_DSA(mvkey_info->pkey);
2923 DSA_get0_pqg(dsa, &p, &q, &g);
2924 DSA_get0_key(dsa, &pub_key, &priv_key);
2927 * Extract r from the challenge.
2929 len = exten_payload_size(ep);
2930 if (len == 0 || len > MAX_VALLEN)
2932 if ((r = BN_bin2bn((u_char *)ep->pkt, len, NULL)) == NULL) {
2933 msyslog(LOG_ERR, "crypto_bob3: %s",
2934 ERR_error_string(ERR_get_error(), NULL));
2939 * Bob rolls random k (0 < k < q), making sure it is not a
2940 * factor of q. He then computes y = r A^k and sends (y, gbar^k,
2941 * and ghat^k) to Alice.
2943 bctx = BN_CTX_new(); k = BN_new(); u = BN_new();
2945 sp = BN_new(); sq = BN_new(); sg = BN_new();
2947 BN_rand(k, BN_num_bits(q), 0, 0);
2948 BN_mod(k, k, q, bctx);
2949 BN_gcd(u, k, q, bctx);
2953 BN_mod_exp(u, g, k, p, bctx); /* A^k r */
2954 BN_mod_mul(sp, u, r, p, bctx);
2955 BN_mod_exp(sq, priv_key, k, p, bctx); /* gbar */
2956 BN_mod_exp(sg, pub_key, k, p, bctx); /* ghat */
2957 DSA_set0_key(sdsa, BN_dup(pub_key), NULL);
2958 DSA_set0_pqg(sdsa, sp, sq, sg);
2959 BN_CTX_free(bctx); BN_free(k); BN_free(r); BN_free(u);
2962 DSA_print_fp(stdout, sdsa, 0);
2966 * Encode the values in ASN.1 and sign. The filestamp is from
2969 memset(vp, 0, sizeof(struct value));
2970 tstamp = crypto_time();
2971 vp->tstamp = htonl(tstamp);
2972 vp->fstamp = htonl(mvkey_info->fstamp);
2973 len = i2d_DSAparams(sdsa, NULL);
2975 msyslog(LOG_ERR, "crypto_bob3: %s",
2976 ERR_error_string(ERR_get_error(), NULL));
2980 vp->vallen = htonl(len);
2983 i2d_DSAparams(sdsa, &ptr);
2988 vp->sig = emalloc(sign_siglen);
2989 ctx = EVP_MD_CTX_new();
2990 EVP_SignInit(ctx, sign_digest);
2991 EVP_SignUpdate(ctx, (u_char *)&vp->tstamp, 12);
2992 EVP_SignUpdate(ctx, vp->ptr, len);
2993 if (EVP_SignFinal(ctx, vp->sig, &len, sign_pkey)) {
2994 INSIST(len <= sign_siglen);
2995 vp->siglen = htonl(len);
2997 EVP_MD_CTX_free(ctx);
3003 * crypto_mv - verify Bob's response to Alice's challenge
3007 * XEVNT_ERR protocol error
3008 * XEVNT_FSP bad filestamp
3009 * XEVNT_ID bad or missing group key
3010 * XEVNT_PUB bad or missing public key
3014 struct exten *ep, /* extension pointer */
3015 struct peer *peer /* peer structure pointer */
3018 DSA *dsa; /* MV parameters */
3019 DSA *sdsa; /* DSA parameters */
3020 BN_CTX *bctx; /* BIGNUM context */
3026 const BIGNUM *pub_key, *priv_key;
3027 const BIGNUM *sp, *sq, *sg;
3030 * If the MV parameters are not valid or no challenge was sent,
3031 * something awful happened or we are being tormented.
3033 if (peer->ident_pkey == NULL) {
3034 msyslog(LOG_NOTICE, "crypto_mv: scheme unavailable");
3037 if (ntohl(ep->fstamp) != peer->ident_pkey->fstamp) {
3038 msyslog(LOG_NOTICE, "crypto_mv: invalid filestamp %u",
3042 if ((dsa = EVP_PKEY_get0_DSA(peer->ident_pkey->pkey)) == NULL) {
3043 msyslog(LOG_NOTICE, "crypto_mv: defective key");
3046 DSA_get0_pqg(dsa, &p, NULL, NULL);
3047 DSA_get0_key(dsa, &pub_key, &priv_key);
3048 if (peer->iffval == NULL) {
3049 msyslog(LOG_NOTICE, "crypto_mv: missing challenge");
3054 * Extract the y, gbar and ghat values from the response.
3056 bctx = BN_CTX_new(); k = BN_new(); u = BN_new(); v = BN_new();
3057 len = ntohl(ep->vallen);
3058 ptr = (u_char *)ep->pkt;
3059 if ((sdsa = d2i_DSAparams(NULL, &ptr, len)) == NULL) {
3060 msyslog(LOG_ERR, "crypto_mv: %s",
3061 ERR_error_string(ERR_get_error(), NULL));
3064 DSA_get0_pqg(sdsa, &sp, &sq, &sg);
3067 * Compute (gbar^xhat ghat^xbar) mod p.
3069 BN_mod_exp(u, sq, pub_key, p, bctx);
3070 BN_mod_exp(v, sg, priv_key, p, bctx);
3071 BN_mod_mul(u, u, v, p, bctx);
3072 BN_mod_mul(u, u, sp, p, bctx);
3075 * The result should match r.
3077 temp = BN_cmp(u, peer->iffval);
3078 BN_CTX_free(bctx); BN_free(k); BN_free(u); BN_free(v);
3079 BN_free(peer->iffval);
3080 peer->iffval = NULL;
3085 msyslog(LOG_NOTICE, "crypto_mv: identity not verified");
3091 ***********************************************************************
3093 * The following routines are used to manipulate certificates *
3095 ***********************************************************************
3098 * cert_sign - sign x509 certificate equest and update value structure.
3100 * The certificate request includes a copy of the host certificate,
3101 * which includes the version number, subject name and public key of the
3102 * host. The resulting certificate includes these values plus the
3103 * serial number, issuer name and valid interval of the server. The
3104 * valid interval extends from the current time to the same time one
3105 * year hence. This may extend the life of the signed certificate beyond
3106 * that of the signer certificate.
3108 * It is convenient to use the NTP seconds of the current time as the
3109 * serial number. In the value structure the timestamp is the current
3110 * time and the filestamp is taken from the extension field. Note this
3111 * routine is called only when the client clock is synchronized to a
3112 * proventic source, so timestamp comparisons are valid.
3114 * The host certificate is valid from the time it was generated for a
3115 * period of one year. A signed certificate is valid from the time of
3116 * signature for a period of one year, but only the host certificate (or
3117 * sign certificate if used) is actually used to encrypt and decrypt
3118 * signatures. The signature trail is built from the client via the
3119 * intermediate servers to the trusted server. Each signature on the
3120 * trail must be valid at the time of signature, but it could happen
3121 * that a signer certificate expire before the signed certificate, which
3122 * remains valid until its expiration.
3126 * XEVNT_CRT bad or missing certificate
3127 * XEVNT_PER host certificate expired
3128 * XEVNT_PUB bad or missing public key
3129 * XEVNT_VFY certificate not verified
3133 struct exten *ep, /* extension field pointer */
3134 struct value *vp /* value pointer */
3137 X509 *req; /* X509 certificate request */
3138 X509 *cert; /* X509 certificate */
3139 X509_EXTENSION *ext; /* certificate extension */
3140 ASN1_INTEGER *serial; /* serial number */
3141 X509_NAME *subj; /* distinguished (common) name */
3142 EVP_PKEY *pkey; /* public key */
3143 EVP_MD_CTX *ctx; /* message digest context */
3144 tstamp_t tstamp; /* NTP timestamp */
3145 struct calendar tscal;
3152 * Decode ASN.1 objects and construct certificate structure.
3153 * Make sure the system clock is synchronized to a proventic
3156 tstamp = crypto_time();
3160 len = exten_payload_size(ep);
3161 if (len == 0 || len > MAX_VALLEN)
3163 cptr = (void *)ep->pkt;
3164 if ((req = d2i_X509(NULL, &cptr, len)) == NULL) {
3165 msyslog(LOG_ERR, "cert_sign: %s",
3166 ERR_error_string(ERR_get_error(), NULL));
3170 * Extract public key and check for errors.
3172 if ((pkey = X509_get_pubkey(req)) == NULL) {
3173 msyslog(LOG_ERR, "cert_sign: %s",
3174 ERR_error_string(ERR_get_error(), NULL));
3180 * Generate X509 certificate signed by this server. If this is a
3181 * trusted host, the issuer name is the group name; otherwise,
3182 * it is the host name. Also copy any extensions that might be
3186 X509_set_version(cert, X509_get_version(req));
3187 serial = ASN1_INTEGER_new();
3188 ASN1_INTEGER_set(serial, tstamp);
3189 X509_set_serialNumber(cert, serial);
3190 X509_gmtime_adj(X509_get_notBefore(cert), 0L);
3191 X509_gmtime_adj(X509_get_notAfter(cert), YEAR);
3192 subj = X509_get_issuer_name(cert);
3193 X509_NAME_add_entry_by_txt(subj, "commonName", MBSTRING_ASC,
3194 hostval.ptr, strlen((const char *)hostval.ptr), -1, 0);
3195 subj = X509_get_subject_name(req);
3196 X509_set_subject_name(cert, subj);
3197 X509_set_pubkey(cert, pkey);
3198 temp = X509_get_ext_count(req);
3199 for (i = 0; i < temp; i++) {
3200 ext = X509_get_ext(req, i);
3201 INSIST(X509_add_ext(cert, ext, -1));
3206 * Sign and verify the client certificate, but only if the host
3207 * certificate has not expired.
3209 (void)ntpcal_ntp_to_date(&tscal, tstamp, NULL);
3210 if ((calcomp(&tscal, &(cert_host->first)) < 0)
3211 || (calcomp(&tscal, &(cert_host->last)) > 0)) {
3215 X509_sign(cert, sign_pkey, sign_digest);
3216 if (X509_verify(cert, sign_pkey) <= 0) {
3217 msyslog(LOG_ERR, "cert_sign: %s",
3218 ERR_error_string(ERR_get_error(), NULL));
3222 len = i2d_X509(cert, NULL);
3225 * Build and sign the value structure. We have to sign it here,
3226 * since the response has to be returned right away. This is a
3229 memset(vp, 0, sizeof(struct value));
3230 vp->tstamp = htonl(tstamp);
3231 vp->fstamp = ep->fstamp;
3232 vp->vallen = htonl(len);
3233 vp->ptr = emalloc(len);
3235 i2d_X509(cert, (unsigned char **)(intptr_t)&ptr);
3238 vp->sig = emalloc(sign_siglen);
3239 ctx = EVP_MD_CTX_new();
3240 EVP_SignInit(ctx, sign_digest);
3241 EVP_SignUpdate(ctx, (u_char *)vp, 12);
3242 EVP_SignUpdate(ctx, vp->ptr, len);
3243 if (EVP_SignFinal(ctx, vp->sig, &len, sign_pkey)) {
3244 INSIST(len <= sign_siglen);
3245 vp->siglen = htonl(len);
3247 EVP_MD_CTX_free(ctx);
3251 X509_print_fp(stdout, cert);
3259 * cert_install - install certificate in certificate cache
3261 * This routine encodes an extension field into a certificate info/value
3262 * structure. It searches the certificate list for duplicates and
3263 * expunges whichever is older. Finally, it inserts this certificate
3264 * first on the list.
3266 * Returns certificate info pointer if valid, NULL if not.
3270 struct exten *ep, /* cert info/value */
3271 struct peer *peer /* peer structure */
3274 struct cert_info *cp, *xp, **zp;
3277 * Parse and validate the signed certificate. If valid,
3278 * construct the info/value structure; otherwise, scamper home
3281 if ((cp = cert_parse((u_char *)ep->pkt, (long)ntohl(ep->vallen),
3282 (tstamp_t)ntohl(ep->fstamp))) == NULL)
3286 * Scan certificate list looking for another certificate with
3287 * the same subject and issuer. If another is found with the
3288 * same or older filestamp, unlink it and return the goodies to
3289 * the heap. If another is found with a later filestamp, discard
3290 * the new one and leave the building with the old one.
3292 * Make a note to study this issue again. An earlier certificate
3293 * with a long lifetime might be overtaken by a later
3294 * certificate with a short lifetime, thus invalidating the
3295 * earlier signature. However, we gotta find a way to leak old
3296 * stuff from the cache, so we do it anyway.
3299 for (xp = cinfo; xp != NULL; xp = xp->link) {
3300 if (strcmp(cp->subject, xp->subject) == 0 &&
3301 strcmp(cp->issuer, xp->issuer) == 0) {
3302 if (ntohl(cp->cert.fstamp) <=
3303 ntohl(xp->cert.fstamp)) {
3319 cp->flags |= CERT_VALID;
3326 * cert_hike - verify the signature using the issuer public key
3330 * XEVNT_CRT bad or missing certificate
3331 * XEVNT_PER host certificate expired
3332 * XEVNT_VFY certificate not verified
3336 struct peer *peer, /* peer structure pointer */
3337 struct cert_info *yp /* issuer certificate */
3340 struct cert_info *xp; /* subject certificate */
3341 X509 *cert; /* X509 certificate */
3345 * Save the issuer on the new certificate, but remember the old
3348 if (peer->issuer != NULL)
3350 peer->issuer = estrdup(yp->issuer);
3355 * If subject Y matches issuer Y, then the certificate trail is
3356 * complete. If Y is not trusted, the server certificate has yet
3357 * been signed, so keep trying. Otherwise, save the group key
3358 * and light the valid bit. If the host certificate is trusted,
3359 * do not execute a sign exchange. If no identity scheme is in
3360 * use, light the identity and proventic bits.
3362 if (strcmp(yp->subject, yp->issuer) == 0) {
3363 if (!(yp->flags & CERT_TRUST))
3367 * If the server has an an identity scheme, fetch the
3368 * identity credentials. If not, the identity is
3369 * verified only by the trusted certificate. The next
3370 * signature will set the server proventic.
3372 peer->crypto |= CRYPTO_FLAG_CERT;
3373 peer->grpkey = yp->grpkey;
3374 if (peer->ident == NULL || !(peer->crypto &
3376 peer->crypto |= CRYPTO_FLAG_VRFY;
3380 * If X exists, verify signature X using public key Y.
3385 ptr = (u_char *)xp->cert.ptr;
3386 cert = d2i_X509(NULL, &ptr, ntohl(xp->cert.vallen));
3388 xp->flags |= CERT_ERROR;
3391 if (X509_verify(cert, yp->pkey) <= 0) {
3393 xp->flags |= CERT_ERROR;
3399 * Signature X is valid only if it begins during the
3402 if ((calcomp(&(xp->first), &(yp->first)) < 0)
3403 || (calcomp(&(xp->first), &(yp->last)) > 0)) {
3404 xp->flags |= CERT_ERROR;
3407 xp->flags |= CERT_SIGN;
3413 * cert_parse - parse x509 certificate and create info/value structures.
3415 * The server certificate includes the version number, issuer name,
3416 * subject name, public key and valid date interval. If the issuer name
3417 * is the same as the subject name, the certificate is self signed and
3418 * valid only if the server is configured as trustable. If the names are
3419 * different, another issuer has signed the server certificate and
3420 * vouched for it. In this case the server certificate is valid if
3421 * verified by the issuer public key.
3423 * Returns certificate info/value pointer if valid, NULL if not.
3425 struct cert_info * /* certificate information structure */
3427 const u_char *asn1cert, /* X509 certificate */
3428 long len, /* certificate length */
3429 tstamp_t fstamp /* filestamp */
3432 X509 *cert; /* X509 certificate */
3433 struct cert_info *ret; /* certificate info/value */
3435 char pathbuf[MAXFILENAME];
3439 struct calendar fscal;
3442 * Decode ASN.1 objects and construct certificate structure.
3445 if ((cert = d2i_X509(NULL, &ptr, len)) == NULL) {
3446 msyslog(LOG_ERR, "cert_parse: %s",
3447 ERR_error_string(ERR_get_error(), NULL));
3452 X509_print_fp(stdout, cert);
3456 * Extract version, subject name and public key.
3458 ret = emalloc_zero(sizeof(*ret));
3459 if ((ret->pkey = X509_get_pubkey(cert)) == NULL) {
3460 msyslog(LOG_ERR, "cert_parse: %s",
3461 ERR_error_string(ERR_get_error(), NULL));
3466 ret->version = X509_get_version(cert);
3467 X509_NAME_oneline(X509_get_subject_name(cert), pathbuf,
3469 pch = strstr(pathbuf, "CN=");
3471 msyslog(LOG_NOTICE, "cert_parse: invalid subject %s",
3477 ret->subject = estrdup(pch + 3);
3480 * Extract remaining objects. Note that the NTP serial number is
3481 * the NTP seconds at the time of signing, but this might not be
3482 * the case for other authority. We don't bother to check the
3483 * objects at this time, since the real crunch can happen only
3484 * when the time is valid but not yet certificated.
3486 ret->nid = X509_get_signature_nid(cert);
3487 ret->digest = (const EVP_MD *)EVP_get_digestbynid(ret->nid);
3489 (u_long)ASN1_INTEGER_get(X509_get_serialNumber(cert));
3490 X509_NAME_oneline(X509_get_issuer_name(cert), pathbuf,
3492 if ((pch = strstr(pathbuf, "CN=")) == NULL) {
3493 msyslog(LOG_NOTICE, "cert_parse: invalid issuer %s",
3499 ret->issuer = estrdup(pch + 3);
3500 asn_to_calendar(X509_get_notBefore(cert), &(ret->first));
3501 asn_to_calendar(X509_get_notAfter(cert), &(ret->last));
3504 * Extract extension fields. These are ad hoc ripoffs of
3505 * currently assigned functions and will certainly be changed
3506 * before prime time.
3508 cnt = X509_get_ext_count(cert);
3509 for (i = 0; i < cnt; i++) {
3510 X509_EXTENSION *ext;
3513 ASN1_OCTET_STRING *data;
3515 ext = X509_get_ext(cert, i);
3516 obj = X509_EXTENSION_get_object(ext);
3517 nid = OBJ_obj2nid(obj);
3522 * If a key_usage field is present, we decode whether
3523 * this is a trusted or private certificate. This is
3524 * dorky; all we want is to compare NIDs, but OpenSSL
3525 * insists on BIO text strings.
3527 case NID_ext_key_usage:
3528 bp = BIO_new(BIO_s_mem());
3529 X509V3_EXT_print(bp, ext, 0, 0);
3530 BIO_gets(bp, pathbuf, sizeof(pathbuf));
3532 if (strcmp(pathbuf, "Trust Root") == 0)
3533 ret->flags |= CERT_TRUST;
3534 else if (strcmp(pathbuf, "Private") == 0)
3535 ret->flags |= CERT_PRIV;
3536 DPRINTF(1, ("cert_parse: %s: %s\n",
3537 OBJ_nid2ln(nid), pathbuf));
3541 * If a NID_subject_key_identifier field is present, it
3542 * contains the GQ public key.
3544 case NID_subject_key_identifier:
3545 data = X509_EXTENSION_get_data(ext);
3546 ret->grpkey = BN_bin2bn(&data->data[2],
3547 data->length - 2, NULL);
3550 DPRINTF(1, ("cert_parse: %s\n",
3555 if (strcmp(ret->subject, ret->issuer) == 0) {
3558 * If certificate is self signed, verify signature.
3560 if (X509_verify(cert, ret->pkey) <= 0) {
3562 "cert_parse: signature not verified %s",
3571 * Check for a certificate loop.
3573 if (strcmp((const char *)hostval.ptr, ret->issuer) == 0) {
3575 "cert_parse: certificate trail loop %s",
3584 * Verify certificate valid times. Note that certificates cannot
3587 (void)ntpcal_ntp_to_date(&fscal, fstamp, NULL);
3588 if ((calcomp(&(ret->first), &(ret->last)) > 0)
3589 || (calcomp(&(ret->first), &fscal) < 0)) {
3591 "cert_parse: invalid times %s first %u-%02u-%02uT%02u:%02u:%02u last %u-%02u-%02uT%02u:%02u:%02u fstamp %u-%02u-%02uT%02u:%02u:%02u",
3593 ret->first.year, ret->first.month, ret->first.monthday,
3594 ret->first.hour, ret->first.minute, ret->first.second,
3595 ret->last.year, ret->last.month, ret->last.monthday,
3596 ret->last.hour, ret->last.minute, ret->last.second,
3597 fscal.year, fscal.month, fscal.monthday,
3598 fscal.hour, fscal.minute, fscal.second);
3605 * Build the value structure to sign and send later.
3607 ret->cert.fstamp = htonl(fstamp);
3608 ret->cert.vallen = htonl(len);
3609 ret->cert.ptr = emalloc(len);
3610 memcpy(ret->cert.ptr, asn1cert, len);
3617 * cert_free - free certificate information structure
3621 struct cert_info *cinf /* certificate info/value structure */
3624 if (cinf->pkey != NULL)
3625 EVP_PKEY_free(cinf->pkey);
3626 if (cinf->subject != NULL)
3627 free(cinf->subject);
3628 if (cinf->issuer != NULL)
3630 if (cinf->grpkey != NULL)
3631 BN_free(cinf->grpkey);
3632 value_free(&cinf->cert);
3638 * crypto_key - load cryptographic parameters and keys
3640 * This routine searches the key cache for matching name in the form
3641 * ntpkey_<key>_<name>, where <key> is one of host, sign, iff, gq, mv,
3642 * and <name> is the host/group name. If not found, it tries to load a
3643 * PEM-encoded file of the same name and extracts the filestamp from
3644 * the first line of the file name. It returns the key pointer if valid,
3647 static struct pkey_info *
3649 char *cp, /* file name */
3650 char *passwd1, /* password */
3651 sockaddr_u *addr /* IP address */
3654 FILE *str; /* file handle */
3655 struct pkey_info *pkp; /* generic key */
3656 EVP_PKEY *pkey = NULL; /* public/private key */
3658 char filename[MAXFILENAME]; /* name of key file */
3659 char linkname[MAXFILENAME]; /* filestamp buffer) */
3660 char statstr[NTP_MAXSTRLEN]; /* statistics for filegen */
3664 * Search the key cache for matching key and name.
3666 for (pkp = pkinfo; pkp != NULL; pkp = pkp->link) {
3667 if (strcmp(cp, pkp->name) == 0)
3672 * Open the key file. If the first character of the file name is
3673 * not '/', prepend the keys directory string. If something goes
3674 * wrong, abandon ship.
3677 strlcpy(filename, cp, sizeof(filename));
3679 snprintf(filename, sizeof(filename), "%s/%s", keysdir,
3681 str = fopen(filename, "r");
3686 * Read the filestamp, which is contained in the first line.
3688 if ((ptr = fgets(linkname, sizeof(linkname), str)) == NULL) {
3689 msyslog(LOG_ERR, "crypto_key: empty file %s",
3694 if ((ptr = strrchr(ptr, '.')) == NULL) {
3695 msyslog(LOG_ERR, "crypto_key: no filestamp %s",
3700 if (sscanf(++ptr, "%u", &fstamp) != 1) {
3701 msyslog(LOG_ERR, "crypto_key: invalid filestamp %s",
3708 * Read and decrypt PEM-encoded private key. If it fails to
3709 * decrypt, game over.
3711 pkey = PEM_read_PrivateKey(str, NULL, NULL, passwd1);
3714 msyslog(LOG_ERR, "crypto_key: %s",
3715 ERR_error_string(ERR_get_error(), NULL));
3720 * Make a new entry in the key cache.
3722 pkp = emalloc(sizeof(struct pkey_info));
3726 pkp->name = estrdup(cp);
3727 pkp->fstamp = fstamp;
3730 * Leave tracks in the cryptostats.
3732 if ((ptr = strrchr(linkname, '\n')) != NULL)
3734 snprintf(statstr, sizeof(statstr), "%s mod %d", &linkname[2],
3735 EVP_PKEY_size(pkey) * 8);
3736 record_crypto_stats(addr, statstr);
3738 DPRINTF(1, ("crypto_key: %s\n", statstr));
3741 if (EVP_PKEY_base_id(pkey) == EVP_PKEY_DSA)
3742 DSA_print_fp(stdout, EVP_PKEY_get0_DSA(pkey), 0);
3743 else if (EVP_PKEY_base_id(pkey) == EVP_PKEY_RSA)
3744 RSA_print_fp(stdout, EVP_PKEY_get0_RSA(pkey), 0);
3752 ***********************************************************************
3754 * The following routines are used only at initialization time *
3756 ***********************************************************************
3759 * crypto_cert - load certificate from file
3761 * This routine loads an X.509 RSA or DSA certificate from a file and
3762 * constructs a info/cert value structure for this machine. The
3763 * structure includes a filestamp extracted from the file name. Later
3764 * the certificate can be sent to another machine on request.
3766 * Returns certificate info/value pointer if valid, NULL if not.
3768 static struct cert_info * /* certificate information */
3770 char *cp /* file name */
3773 struct cert_info *ret; /* certificate information */
3774 FILE *str; /* file handle */
3775 char filename[MAXFILENAME]; /* name of certificate file */
3776 char linkname[MAXFILENAME]; /* filestamp buffer */
3777 char statstr[NTP_MAXSTRLEN]; /* statistics for filegen */
3778 tstamp_t fstamp; /* filestamp */
3781 char *name, *header;
3785 * Open the certificate file. If the first character of the file
3786 * name is not '/', prepend the keys directory string. If
3787 * something goes wrong, abandon ship.
3790 strlcpy(filename, cp, sizeof(filename));
3792 snprintf(filename, sizeof(filename), "%s/%s", keysdir,
3794 str = fopen(filename, "r");
3799 * Read the filestamp, which is contained in the first line.
3801 if ((ptr = fgets(linkname, sizeof(linkname), str)) == NULL) {
3802 msyslog(LOG_ERR, "crypto_cert: empty file %s",
3807 if ((ptr = strrchr(ptr, '.')) == NULL) {
3808 msyslog(LOG_ERR, "crypto_cert: no filestamp %s",
3813 if (sscanf(++ptr, "%u", &fstamp) != 1) {
3814 msyslog(LOG_ERR, "crypto_cert: invalid filestamp %s",
3821 * Read PEM-encoded certificate and install.
3823 if (!PEM_read(str, &name, &header, &data, &len)) {
3824 msyslog(LOG_ERR, "crypto_cert: %s",
3825 ERR_error_string(ERR_get_error(), NULL));
3831 if (strcmp(name, "CERTIFICATE") != 0) {
3832 msyslog(LOG_NOTICE, "crypto_cert: wrong PEM type %s",
3841 * Parse certificate and generate info/value structure. The
3842 * pointer and copy nonsense is due something broken in Solaris.
3844 ret = cert_parse(data, len, fstamp);
3849 if ((ptr = strrchr(linkname, '\n')) != NULL)
3851 snprintf(statstr, sizeof(statstr), "%s 0x%x len %lu",
3852 &linkname[2], ret->flags, len);
3853 record_crypto_stats(NULL, statstr);
3854 DPRINTF(1, ("crypto_cert: %s\n", statstr));
3860 * crypto_setup - load keys, certificate and identity parameters
3862 * This routine loads the public/private host key and certificate. If
3863 * available, it loads the public/private sign key, which defaults to
3864 * the host key. The host key must be RSA, but the sign key can be
3865 * either RSA or DSA. If a trusted certificate, it loads the identity
3866 * parameters. In either case, the public key on the certificate must
3867 * agree with the sign key.
3869 * Required but missing files and inconsistent data and errors are
3870 * fatal. Allowing configuration to continue would be hazardous and
3871 * require really messy error checks.
3876 struct pkey_info *pinfo; /* private/public key */
3877 char filename[MAXFILENAME]; /* file name buffer */
3878 char hostname[MAXFILENAME]; /* host name buffer */
3880 char statstr[NTP_MAXSTRLEN]; /* statistics for filegen */
3881 l_fp seed; /* crypto PRNG seed as NTP timestamp */
3887 * Check for correct OpenSSL version and avoid initialization in
3888 * the case of multiple crypto commands.
3890 if (crypto_flags & CRYPTO_FLAG_ENAB) {
3892 "crypto_setup: spurious crypto command");
3895 ssl_check_version();
3898 * Load required random seed file and seed the random number
3899 * generator. Be default, it is found as .rnd in the user home
3900 * directory. The root home directory may be / or /root,
3901 * depending on the system. Wiggle the contents a bit and write
3902 * it back so the sequence does not repeat when we next restart.
3904 if (!RAND_status()) {
3905 if (rand_file == NULL) {
3906 RAND_file_name(filename, sizeof(filename));
3907 randfile = filename;
3908 } else if (*rand_file != '/') {
3909 snprintf(filename, sizeof(filename), "%s/%s",
3910 keysdir, rand_file);
3911 randfile = filename;
3913 randfile = rand_file;
3915 if ((bytes = RAND_load_file(randfile, -1)) == 0) {
3917 "crypto_setup: random seed file %s missing",
3921 arc4random_buf(&seed, sizeof(l_fp));
3922 RAND_seed(&seed, sizeof(l_fp));
3923 RAND_write_file(randfile);
3924 DPRINTF(1, ("crypto_setup: OpenSSL version %lx random seed file %s bytes read %d\n",
3925 SSLeay(), randfile, bytes));
3929 * Initialize structures.
3931 gethostname(hostname, sizeof(hostname));
3932 if (host_filename != NULL)
3933 strlcpy(hostname, host_filename, sizeof(hostname));
3935 passwd = estrdup(hostname);
3936 memset(&hostval, 0, sizeof(hostval));
3937 memset(&pubkey, 0, sizeof(pubkey));
3938 memset(&tai_leap, 0, sizeof(tai_leap));
3941 * Load required host key from file "ntpkey_host_<hostname>". If
3942 * no host key file is not found or has invalid password, life
3943 * as we know it ends. The host key also becomes the default
3946 snprintf(filename, sizeof(filename), "ntpkey_host_%s", hostname);
3947 pinfo = crypto_key(filename, passwd, NULL);
3948 if (pinfo == NULL) {
3950 "crypto_setup: host key file %s not found or corrupt",
3954 if (EVP_PKEY_base_id(pinfo->pkey) != EVP_PKEY_RSA) {
3956 "crypto_setup: host key is not RSA key type");
3959 host_pkey = pinfo->pkey;
3960 sign_pkey = host_pkey;
3961 hostval.fstamp = htonl(pinfo->fstamp);
3964 * Construct public key extension field for agreement scheme.
3966 len = i2d_PublicKey(host_pkey, NULL);
3969 i2d_PublicKey(host_pkey, &ptr);
3970 pubkey.fstamp = hostval.fstamp;
3971 pubkey.vallen = htonl(len);
3974 * Load optional sign key from file "ntpkey_sign_<hostname>". If
3975 * available, it becomes the sign key.
3977 snprintf(filename, sizeof(filename), "ntpkey_sign_%s", hostname);
3978 pinfo = crypto_key(filename, passwd, NULL);
3980 sign_pkey = pinfo->pkey;
3983 * Load required certificate from file "ntpkey_cert_<hostname>".
3985 snprintf(filename, sizeof(filename), "ntpkey_cert_%s", hostname);
3986 cinfo = crypto_cert(filename);
3987 if (cinfo == NULL) {
3989 "crypto_setup: certificate file %s not found or corrupt",
3994 sign_digest = cinfo->digest;
3995 sign_siglen = EVP_PKEY_size(sign_pkey);
3996 if (cinfo->flags & CERT_PRIV)
3997 crypto_flags |= CRYPTO_FLAG_PRIV;
4000 * The certificate must be self-signed.
4002 if (strcmp(cinfo->subject, cinfo->issuer) != 0) {
4004 "crypto_setup: certificate %s is not self-signed",
4008 hostval.ptr = estrdup(cinfo->subject);
4009 hostval.vallen = htonl(strlen(cinfo->subject));
4010 sys_hostname = hostval.ptr;
4011 ptr = (u_char *)strchr(sys_hostname, '@');
4013 sys_groupname = estrdup((char *)++ptr);
4014 if (ident_filename != NULL)
4015 strlcpy(hostname, ident_filename, sizeof(hostname));
4018 * Load optional IFF parameters from file
4019 * "ntpkey_iffkey_<hostname>".
4021 snprintf(filename, sizeof(filename), "ntpkey_iffkey_%s",
4023 iffkey_info = crypto_key(filename, passwd, NULL);
4024 if (iffkey_info != NULL)
4025 crypto_flags |= CRYPTO_FLAG_IFF;
4028 * Load optional GQ parameters from file
4029 * "ntpkey_gqkey_<hostname>".
4031 snprintf(filename, sizeof(filename), "ntpkey_gqkey_%s",
4033 gqkey_info = crypto_key(filename, passwd, NULL);
4034 if (gqkey_info != NULL)
4035 crypto_flags |= CRYPTO_FLAG_GQ;
4038 * Load optional MV parameters from file
4039 * "ntpkey_mvkey_<hostname>".
4041 snprintf(filename, sizeof(filename), "ntpkey_mvkey_%s",
4043 mvkey_info = crypto_key(filename, passwd, NULL);
4044 if (mvkey_info != NULL)
4045 crypto_flags |= CRYPTO_FLAG_MV;
4048 * We met the enemy and he is us. Now strike up the dance.
4050 crypto_flags |= CRYPTO_FLAG_ENAB | (cinfo->nid << 16);
4051 snprintf(statstr, sizeof(statstr), "setup 0x%x host %s %s",
4052 crypto_flags, hostname, OBJ_nid2ln(cinfo->nid));
4053 record_crypto_stats(NULL, statstr);
4054 DPRINTF(1, ("crypto_setup: %s\n", statstr));
4059 * crypto_config - configure data from the crypto command.
4063 int item, /* configuration item */
4064 char *cp /* item name */
4069 DPRINTF(1, ("crypto_config: item %d %s\n", item, cp));
4074 * Set host name (host).
4076 case CRYPTO_CONF_PRIV:
4077 if (NULL != host_filename)
4078 free(host_filename);
4079 host_filename = estrdup(cp);
4083 * Set group name (ident).
4085 case CRYPTO_CONF_IDENT:
4086 if (NULL != ident_filename)
4087 free(ident_filename);
4088 ident_filename = estrdup(cp);
4092 * Set private key password (pw).
4094 case CRYPTO_CONF_PW:
4097 passwd = estrdup(cp);
4101 * Set random seed file name (randfile).
4103 case CRYPTO_CONF_RAND:
4104 if (NULL != rand_file)
4106 rand_file = estrdup(cp);
4110 * Set message digest NID.
4112 case CRYPTO_CONF_NID:
4113 nid = OBJ_sn2nid(cp);
4116 "crypto_config: invalid digest name %s", cp);
4124 * Get the payload size (internal value length) of an extension packet.
4125 * If the inner value size does not match the outer packet size (that
4126 * is, the value would end behind the frame given by the opcode/size
4127 * field) the function will effectively return UINT_MAX. If the frame is
4128 * too short to hold a variable-sized value, the return value is zero.
4132 const struct exten * ep)
4134 typedef const u_char *BPTR;
4142 head_size = (BPTR)(&ep->vallen + 1) - (BPTR)ep;
4143 extn_size = (uint16_t)(ntohl(ep->opcode) & 0x0000ffff);
4144 if (extn_size >= head_size) {
4145 data_size = (uint32_t)ntohl(ep->vallen);
4146 if (data_size > extn_size - head_size)
4147 data_size = ~(size_t)0u;
4150 return (u_int)data_size;
4152 # else /* !AUTOKEY follows */
4153 int ntp_crypto_bs_pubkey;
4154 # endif /* !AUTOKEY */