2 * ntp_crypto.c - NTP version 4 public key routines
10 #include <sys/types.h>
11 #include <sys/param.h>
16 #include "ntp_stdlib.h"
17 #include "ntp_unixtime.h"
18 #include "ntp_string.h"
19 #include <ntp_random.h>
21 #include "openssl/asn1_mac.h"
22 #include "openssl/bn.h"
23 #include "openssl/err.h"
24 #include "openssl/evp.h"
25 #include "openssl/pem.h"
26 #include "openssl/rand.h"
27 #include "openssl/x509v3.h"
30 #include "ntp_syscall.h"
31 #endif /* KERNEL_PLL */
34 * Extension field message format
36 * These are always signed and saved before sending in network byte
37 * order. They must be converted to and from host byte order for
41 * | op | len | <- extension pointer
45 * | timestamp | <- value pointer
62 * The CRYPTO_RESP bit is set to 0 for requests, 1 for responses.
63 * Requests carry the association ID of the receiver; responses carry
64 * the association ID of the sender. Some messages include only the
65 * operation/length and association ID words and so have length 8
66 * octets. Ohers include the value structure and associated value and
67 * signature fields. These messages include the timestamp, filestamp,
68 * value and signature words and so have length at least 24 octets. The
69 * signature and/or value fields can be empty, in which case the
70 * respective length words are zero. An empty value with nonempty
71 * signature is syntactically valid, but semantically questionable.
73 * The filestamp represents the time when a cryptographic data file such
74 * as a public/private key pair is created. It follows every reference
75 * depending on that file and serves as a means to obsolete earlier data
76 * of the same type. The timestamp represents the time when the
77 * cryptographic data of the message were last signed. Creation of a
78 * cryptographic data file or signing a message can occur only when the
79 * creator or signor is synchronized to an authoritative source and
80 * proventicated to a trusted authority.
82 * Note there are four conditions required for server trust. First, the
83 * public key on the certificate must be verified, which involves a
84 * number of format, content and consistency checks. Next, the server
85 * identity must be confirmed by one of four schemes: private
86 * certificate, IFF scheme, GQ scheme or certificate trail hike to a
87 * self signed trusted certificate. Finally, the server signature must
93 #define TAI_1972 10 /* initial TAI offset (s) */
94 #define MAX_LEAP 100 /* max UTC leapseconds (s) */
95 #define VALUE_LEN (6 * 4) /* min response field length */
96 #define YEAR (60 * 60 * 24 * 365) /* seconds in year */
99 * Global cryptodata in host byte order
101 u_int32 crypto_flags = 0x0; /* status word */
104 * Global cryptodata in network byte order
106 struct cert_info *cinfo = NULL; /* certificate info/value */
107 struct value hostval; /* host value */
108 struct value pubkey; /* public key */
109 struct value tai_leap; /* leapseconds table */
110 EVP_PKEY *iffpar_pkey = NULL; /* IFF parameters */
111 EVP_PKEY *gqpar_pkey = NULL; /* GQ parameters */
112 EVP_PKEY *mvpar_pkey = NULL; /* MV parameters */
113 char *iffpar_file = NULL; /* IFF parameters file */
114 char *gqpar_file = NULL; /* GQ parameters file */
115 char *mvpar_file = NULL; /* MV parameters file */
118 * Private cryptodata in host byte order
120 static char *passwd = NULL; /* private key password */
121 static EVP_PKEY *host_pkey = NULL; /* host key */
122 static EVP_PKEY *sign_pkey = NULL; /* sign key */
123 static const EVP_MD *sign_digest = NULL; /* sign digest */
124 static u_int sign_siglen; /* sign key length */
125 static char *rand_file = NULL; /* random seed file */
126 static char *host_file = NULL; /* host key file */
127 static char *sign_file = NULL; /* sign key file */
128 static char *cert_file = NULL; /* certificate file */
129 static char *leap_file = NULL; /* leapseconds file */
130 static tstamp_t if_fstamp = 0; /* IFF filestamp */
131 static tstamp_t gq_fstamp = 0; /* GQ file stamp */
132 static tstamp_t mv_fstamp = 0; /* MV filestamp */
133 static u_int ident_scheme = 0; /* server identity scheme */
138 static int crypto_verify P((struct exten *, struct value *,
140 static int crypto_encrypt P((struct exten *, struct value *,
142 static int crypto_alice P((struct peer *, struct value *));
143 static int crypto_alice2 P((struct peer *, struct value *));
144 static int crypto_alice3 P((struct peer *, struct value *));
145 static int crypto_bob P((struct exten *, struct value *));
146 static int crypto_bob2 P((struct exten *, struct value *));
147 static int crypto_bob3 P((struct exten *, struct value *));
148 static int crypto_iff P((struct exten *, struct peer *));
149 static int crypto_gq P((struct exten *, struct peer *));
150 static int crypto_mv P((struct exten *, struct peer *));
151 static u_int crypto_send P((struct exten *, struct value *));
152 static tstamp_t crypto_time P((void));
153 static u_long asn2ntp P((ASN1_TIME *));
154 static struct cert_info *cert_parse P((u_char *, u_int, tstamp_t));
155 static int cert_sign P((struct exten *, struct value *));
156 static int cert_valid P((struct cert_info *, EVP_PKEY *));
157 static int cert_install P((struct exten *, struct peer *));
158 static void cert_free P((struct cert_info *));
159 static EVP_PKEY *crypto_key P((char *, tstamp_t *));
160 static int bighash P((BIGNUM *, BIGNUM *));
161 static struct cert_info *crypto_cert P((char *));
162 static void crypto_tai P((char *));
166 readlink(char * link, char * file, int len) {
172 * session_key - generate session key
174 * This routine generates a session key from the source address,
175 * destination address, key ID and private value. The value of the
176 * session key is the MD5 hash of these values, while the next key ID is
177 * the first four octets of the hash.
179 * Returns the next key ID
183 struct sockaddr_storage *srcadr, /* source address */
184 struct sockaddr_storage *dstadr, /* destination address */
185 keyid_t keyno, /* key ID */
186 keyid_t private, /* private value */
187 u_long lifetime /* key lifetime */
190 EVP_MD_CTX ctx; /* message digest context */
191 u_char dgst[EVP_MAX_MD_SIZE]; /* message digest */
192 keyid_t keyid; /* key identifer */
193 u_int32 header[10]; /* data in network byte order */
200 * Generate the session key and key ID. If the lifetime is
201 * greater than zero, install the key and call it trusted.
204 switch(srcadr->ss_family) {
206 header[0] = ((struct sockaddr_in *)srcadr)->sin_addr.s_addr;
207 header[1] = ((struct sockaddr_in *)dstadr)->sin_addr.s_addr;
208 header[2] = htonl(keyno);
209 header[3] = htonl(private);
210 hdlen = 4 * sizeof(u_int32);
214 memcpy(&header[0], &GET_INADDR6(*srcadr),
215 sizeof(struct in6_addr));
216 memcpy(&header[4], &GET_INADDR6(*dstadr),
217 sizeof(struct in6_addr));
218 header[8] = htonl(keyno);
219 header[9] = htonl(private);
220 hdlen = 10 * sizeof(u_int32);
223 EVP_DigestInit(&ctx, EVP_md5());
224 EVP_DigestUpdate(&ctx, (u_char *)header, hdlen);
225 EVP_DigestFinal(&ctx, dgst, &len);
226 memcpy(&keyid, dgst, 4);
227 keyid = ntohl(keyid);
229 MD5auth_setkey(keyno, dgst, len);
230 authtrust(keyno, lifetime);
235 "session_key: %s > %s %08x %08x hash %08x life %lu\n",
236 stoa(srcadr), stoa(dstadr), keyno,
237 private, keyid, lifetime);
244 * make_keylist - generate key list
248 * XEVNT_PER host certificate expired
250 * This routine constructs a pseudo-random sequence by repeatedly
251 * hashing the session key starting from a given source address,
252 * destination address, private value and the next key ID of the
253 * preceeding session key. The last entry on the list is saved along
254 * with its sequence number and public signature.
258 struct peer *peer, /* peer structure pointer */
259 struct interface *dstadr /* interface */
262 EVP_MD_CTX ctx; /* signature context */
263 tstamp_t tstamp; /* NTP timestamp */
264 struct autokey *ap; /* autokey pointer */
265 struct value *vp; /* value pointer */
266 keyid_t keyid = 0; /* next key ID */
267 keyid_t cookie; /* private value */
276 * Allocate the key list if necessary.
278 tstamp = crypto_time();
279 if (peer->keylist == NULL)
280 peer->keylist = emalloc(sizeof(keyid_t) *
284 * Generate an initial key ID which is unique and greater than
288 keyid = (ntp_random() + NTP_MAXKEY + 1) & ((1 <<
289 sizeof(keyid_t)) - 1);
290 if (authhavekey(keyid))
296 * Generate up to NTP_MAXSESSION session keys. Stop if the
297 * next one would not be unique or not a session key ID or if
298 * it would expire before the next poll. The private value
299 * included in the hash is zero if broadcast mode, the peer
300 * cookie if client mode or the host cookie if symmetric modes.
302 mpoll = 1 << min(peer->ppoll, peer->hpoll);
303 lifetime = min(sys_automax, NTP_MAXSESSION * mpoll);
304 if (peer->hmode == MODE_BROADCAST)
307 cookie = peer->pcookie;
308 for (i = 0; i < NTP_MAXSESSION; i++) {
309 peer->keylist[i] = keyid;
311 keyid = session_key(&dstadr->sin, &peer->srcadr, keyid,
314 if (auth_havekey(keyid) || keyid <= NTP_MAXKEY ||
320 * Save the last session key ID, sequence number and timestamp,
321 * then sign these values for later retrieval by the clients. Be
322 * careful not to use invalid key media. Use the public values
323 * timestamp as filestamp.
327 vp->ptr = emalloc(sizeof(struct autokey));
328 ap = (struct autokey *)vp->ptr;
329 ap->seq = htonl(peer->keynumber);
330 ap->key = htonl(keyid);
331 vp->tstamp = htonl(tstamp);
332 vp->fstamp = hostval.tstamp;
333 vp->vallen = htonl(sizeof(struct autokey));
336 if (tstamp < cinfo->first || tstamp > cinfo->last)
340 vp->sig = emalloc(sign_siglen);
341 EVP_SignInit(&ctx, sign_digest);
342 EVP_SignUpdate(&ctx, (u_char *)vp, 12);
343 EVP_SignUpdate(&ctx, vp->ptr, sizeof(struct autokey));
344 if (EVP_SignFinal(&ctx, vp->sig, &len, sign_pkey))
345 vp->siglen = htonl(len);
347 msyslog(LOG_ERR, "make_keys %s\n",
348 ERR_error_string(ERR_get_error(), NULL));
349 peer->flags |= FLAG_ASSOC;
353 printf("make_keys: %d %08x %08x ts %u fs %u poll %d\n",
354 ntohl(ap->seq), ntohl(ap->key), cookie,
355 ntohl(vp->tstamp), ntohl(vp->fstamp), peer->hpoll);
362 * crypto_recv - parse extension fields
364 * This routine is called when the packet has been matched to an
365 * association and passed sanity, format and MAC checks. We believe the
366 * extension field values only if the field has proper format and
367 * length, the timestamp and filestamp are valid and the signature has
368 * valid length and is verified. There are a few cases where some values
369 * are believed even if the signature fails, but only if the proventic
374 struct peer *peer, /* peer structure pointer */
375 struct recvbuf *rbufp /* packet buffer pointer */
378 const EVP_MD *dp; /* message digest algorithm */
379 u_int32 *pkt; /* receive packet pointer */
380 struct autokey *ap, *bp; /* autokey pointer */
381 struct exten *ep, *fp; /* extension pointers */
382 int has_mac; /* length of MAC field */
383 int authlen; /* offset of MAC field */
384 associd_t associd; /* association ID */
385 tstamp_t tstamp = 0; /* timestamp */
386 tstamp_t fstamp = 0; /* filestamp */
387 u_int len; /* extension field length */
388 u_int code; /* extension field opcode */
389 u_int vallen = 0; /* value length */
390 X509 *cert; /* X509 certificate */
391 char statstr[NTP_MAXSTRLEN]; /* statistics for filegen */
392 keyid_t cookie; /* crumbles */
393 int hismode; /* packet mode */
399 * Initialize. Note that the packet has already been checked for
400 * valid format and extension field lengths. First extract the
401 * field length, command code and association ID in host byte
402 * order. These are used with all commands and modes. Then check
403 * the version number, which must be 2, and length, which must
404 * be at least 8 for requests and VALUE_LEN (24) for responses.
405 * Packets that fail either test sink without a trace. The
406 * association ID is saved only if nonzero.
408 authlen = LEN_PKT_NOMAC;
409 hismode = (int)PKT_MODE((&rbufp->recv_pkt)->li_vn_mode);
410 while ((has_mac = rbufp->recv_length - authlen) > MAX_MAC_LEN) {
411 pkt = (u_int32 *)&rbufp->recv_pkt + authlen / 4;
412 ep = (struct exten *)pkt;
413 code = ntohl(ep->opcode) & 0xffff0000;
414 len = ntohl(ep->opcode) & 0x0000ffff;
415 associd = (associd_t) ntohl(pkt[1]);
420 "crypto_recv: flags 0x%x ext offset %d len %u code 0x%x assocID %d\n",
421 peer->crypto, authlen, len, code >> 16,
426 * Check version number and field length. If bad,
427 * quietly ignore the packet.
429 if (((code >> 24) & 0x3f) != CRYPTO_VN || len < 8) {
430 sys_unknownversion++;
431 code |= CRYPTO_ERROR;
435 * Little vulnerability bandage here. If a perp tosses a
436 * fake association ID over the fence, we better toss it
437 * out. Only the first one counts.
439 if (code & CRYPTO_RESP) {
440 if (peer->assoc == 0)
441 peer->assoc = associd;
442 else if (peer->assoc != associd)
443 code |= CRYPTO_ERROR;
445 if (len >= VALUE_LEN) {
446 tstamp = ntohl(ep->tstamp);
447 fstamp = ntohl(ep->fstamp);
448 vallen = ntohl(ep->vallen);
453 * Install status word, host name, signature scheme and
454 * association ID. In OpenSSL the signature algorithm is
455 * bound to the digest algorithm, so the NID completely
456 * defines the signature scheme. Note the request and
457 * response are identical, but neither is validated by
458 * signature. The request is processed here only in
459 * symmetric modes. The server name field might be
460 * useful to implement access controls in future.
465 * If the machine is running when this message
466 * arrives, the other fellow has reset and so
467 * must we. Otherwise, pass the extension field
468 * to the transmit side.
476 temp32 = CRYPTO_RESP;
477 fp->opcode |= htonl(temp32);
481 case CRYPTO_ASSOC | CRYPTO_RESP:
484 * Discard the message if it has already been
485 * stored or the message has been amputated.
490 if (vallen == 0 || vallen > MAXHOSTNAME ||
491 len < VALUE_LEN + vallen) {
497 * Check the identity schemes are compatible. If
498 * the client has PC, the server must have PC,
499 * in which case the server public key and
500 * identity are presumed valid, so we skip the
501 * certificate and identity exchanges and move
502 * immediately to the cookie exchange which
503 * confirms the server signature.
508 "crypto_recv: ident host 0x%x server 0x%x\n",
509 crypto_flags, fstamp);
511 temp32 = (crypto_flags | ident_scheme) &
512 fstamp & CRYPTO_FLAG_MASK;
513 if (crypto_flags & CRYPTO_FLAG_PRIV) {
514 if (!(fstamp & CRYPTO_FLAG_PRIV)) {
519 fstamp |= CRYPTO_FLAG_VALID |
524 * In symmetric modes it is an error if either
525 * peer requests identity and the other peer
526 * does not support it.
528 } else if ((hismode == MODE_ACTIVE || hismode ==
529 MODE_PASSIVE) && ((crypto_flags | fstamp) &
530 CRYPTO_FLAG_MASK) && !temp32) {
534 * It is an error if the client requests
535 * identity and the server does not support it.
537 } else if (hismode == MODE_CLIENT && (fstamp &
538 CRYPTO_FLAG_MASK) && !temp32) {
544 * Otherwise, the identity scheme(s) are those
545 * that both client and server support.
547 fstamp = temp32 | (fstamp & ~CRYPTO_FLAG_MASK);
550 * Discard the message if the signature digest
551 * NID is not supported.
553 temp32 = (fstamp >> 16) & 0xffff;
555 (const EVP_MD *)EVP_get_digestbynid(temp32);
562 * Save status word, host name and message
563 * digest/signature type.
565 peer->crypto = fstamp;
567 peer->subject = emalloc(vallen + 1);
568 memcpy(peer->subject, ep->pkt, vallen);
569 peer->subject[vallen] = '\0';
570 peer->issuer = emalloc(vallen + 1);
571 strcpy(peer->issuer, peer->subject);
572 temp32 = (fstamp >> 16) & 0xffff;
573 snprintf(statstr, NTP_MAXSTRLEN,
574 "flags 0x%x host %s signature %s", fstamp,
575 peer->subject, OBJ_nid2ln(temp32));
576 record_crypto_stats(&peer->srcadr, statstr);
579 printf("crypto_recv: %s\n", statstr);
584 * Decode X509 certificate in ASN.1 format and extract
585 * the data containing, among other things, subject
586 * name and public key. In the default identification
587 * scheme, the certificate trail is followed to a self
588 * signed trusted certificate.
590 case CRYPTO_CERT | CRYPTO_RESP:
593 * Discard the message if invalid.
595 if ((rval = crypto_verify(ep, NULL, peer)) !=
600 * Scan the certificate list to delete old
601 * versions and link the newest version first on
604 if ((rval = cert_install(ep, peer)) != XEVNT_OK)
608 * If we snatch the certificate before the
609 * server certificate has been signed by its
610 * server, it will be self signed. When it is,
611 * we chase the certificate issuer, which the
612 * server has, and keep going until a self
613 * signed trusted certificate is found. Be sure
614 * to update the issuer field, since it may
617 if (peer->issuer != NULL)
619 peer->issuer = emalloc(strlen(cinfo->issuer) +
621 strcpy(peer->issuer, cinfo->issuer);
624 * We plug in the public key and lifetime from
625 * the first certificate received. However, note
626 * that this certificate might not be signed by
627 * the server, so we can't check the
628 * signature/digest NID.
630 if (peer->pkey == NULL) {
631 ptr = (u_char *)cinfo->cert.ptr;
632 cert = d2i_X509(NULL, &ptr,
633 ntohl(cinfo->cert.vallen));
634 peer->pkey = X509_get_pubkey(cert);
637 peer->flash &= ~TEST8;
639 snprintf(statstr, NTP_MAXSTRLEN,
640 "cert %s 0x%x %s (%u) fs %u",
641 cinfo->subject, cinfo->flags,
642 OBJ_nid2ln(temp32), temp32,
644 record_crypto_stats(&peer->srcadr, statstr);
647 printf("crypto_recv: %s\n", statstr);
652 * Schnorr (IFF)identity scheme. This scheme is designed
653 * for use with shared secret group keys and where the
654 * certificate may be generated by a third party. The
655 * client sends a challenge to the server, which
656 * performs a calculation and returns the result. A
657 * positive result is possible only if both client and
658 * server contain the same secret group key.
660 case CRYPTO_IFF | CRYPTO_RESP:
663 * Discard the message if invalid or certificate
666 if (!(peer->crypto & CRYPTO_FLAG_VALID)) {
670 if ((rval = crypto_verify(ep, NULL, peer)) !=
675 * If the the challenge matches the response,
676 * the certificate public key, as well as the
677 * server public key, signatyre and identity are
678 * all verified at the same time. The server is
679 * declared trusted, so we skip further
680 * certificate stages and move immediately to
683 if ((rval = crypto_iff(ep, peer)) != XEVNT_OK)
686 peer->crypto |= CRYPTO_FLAG_VRFY |
688 peer->flash &= ~TEST8;
689 snprintf(statstr, NTP_MAXSTRLEN, "iff fs %u",
691 record_crypto_stats(&peer->srcadr, statstr);
694 printf("crypto_recv: %s\n", statstr);
699 * Guillou-Quisquater (GQ) identity scheme. This scheme
700 * is designed for use with public certificates carrying
701 * the GQ public key in an extension field. The client
702 * sends a challenge to the server, which performs a
703 * calculation and returns the result. A positive result
704 * is possible only if both client and server contain
705 * the same group key and the server has the matching GQ
708 case CRYPTO_GQ | CRYPTO_RESP:
711 * Discard the message if invalid or certificate
714 if (!(peer->crypto & CRYPTO_FLAG_VALID)) {
718 if ((rval = crypto_verify(ep, NULL, peer)) !=
723 * If the the challenge matches the response,
724 * the certificate public key, as well as the
725 * server public key, signatyre and identity are
726 * all verified at the same time. The server is
727 * declared trusted, so we skip further
728 * certificate stages and move immediately to
731 if ((rval = crypto_gq(ep, peer)) != XEVNT_OK)
734 peer->crypto |= CRYPTO_FLAG_VRFY |
736 peer->flash &= ~TEST8;
737 snprintf(statstr, NTP_MAXSTRLEN, "gq fs %u",
739 record_crypto_stats(&peer->srcadr, statstr);
742 printf("crypto_recv: %s\n", statstr);
749 case CRYPTO_MV | CRYPTO_RESP:
752 * Discard the message if invalid or certificate
755 if (!(peer->crypto & CRYPTO_FLAG_VALID)) {
759 if ((rval = crypto_verify(ep, NULL, peer)) !=
764 * If the the challenge matches the response,
765 * the certificate public key, as well as the
766 * server public key, signatyre and identity are
767 * all verified at the same time. The server is
768 * declared trusted, so we skip further
769 * certificate stages and move immediately to
772 if ((rval = crypto_mv(ep, peer)) != XEVNT_OK)
775 peer->crypto |= CRYPTO_FLAG_VRFY |
777 peer->flash &= ~TEST8;
778 snprintf(statstr, NTP_MAXSTRLEN, "mv fs %u",
780 record_crypto_stats(&peer->srcadr, statstr);
783 printf("crypto_recv: %s\n", statstr);
788 * Cookie request in symmetric modes. Roll a random
789 * cookie and install in symmetric mode. Encrypt for the
790 * response, which is transmitted later.
795 * Discard the message if invalid or certificate
798 if (!(peer->crypto & CRYPTO_FLAG_VALID)) {
802 if ((rval = crypto_verify(ep, NULL, peer)) !=
807 * Pass the extension field to the transmit
808 * side. If already agreed, walk away.
812 temp32 = CRYPTO_RESP;
813 fp->opcode |= htonl(temp32);
815 if (peer->crypto & CRYPTO_FLAG_AGREE) {
816 peer->flash &= ~TEST8;
821 * Install cookie values and light the cookie
822 * bit. The transmit side will pick up and
823 * encrypt it for the response.
826 peer->cookval.tstamp = ep->tstamp;
827 peer->cookval.fstamp = ep->fstamp;
828 RAND_bytes((u_char *)&peer->pcookie, 4);
829 peer->crypto &= ~CRYPTO_FLAG_AUTO;
830 peer->crypto |= CRYPTO_FLAG_AGREE;
831 peer->flash &= ~TEST8;
832 snprintf(statstr, NTP_MAXSTRLEN, "cook %x ts %u fs %u",
833 peer->pcookie, ntohl(ep->tstamp),
835 record_crypto_stats(&peer->srcadr, statstr);
838 printf("crypto_recv: %s\n", statstr);
843 * Cookie response in client and symmetric modes. If the
844 * cookie bit is set, the working cookie is the EXOR of
845 * the current and new values.
847 case CRYPTO_COOK | CRYPTO_RESP:
850 * Discard the message if invalid or identity
851 * not confirmed or signature not verified with
852 * respect to the cookie values.
854 if (!(peer->crypto & CRYPTO_FLAG_VRFY)) {
858 if ((rval = crypto_verify(ep, &peer->cookval,
863 * Decrypt the cookie, hunting all the time for
866 if (vallen == (u_int) EVP_PKEY_size(host_pkey)) {
867 RSA_private_decrypt(vallen,
871 RSA_PKCS1_OAEP_PADDING);
872 cookie = ntohl(temp32);
879 * Install cookie values and light the cookie
880 * bit. If this is not broadcast client mode, we
884 peer->cookval.tstamp = ep->tstamp;
885 peer->cookval.fstamp = ep->fstamp;
886 if (peer->crypto & CRYPTO_FLAG_AGREE)
887 peer->pcookie ^= cookie;
889 peer->pcookie = cookie;
890 if (peer->hmode == MODE_CLIENT &&
891 !(peer->cast_flags & MDF_BCLNT))
892 peer->crypto |= CRYPTO_FLAG_AUTO;
894 peer->crypto &= ~CRYPTO_FLAG_AUTO;
895 peer->crypto |= CRYPTO_FLAG_AGREE;
896 peer->flash &= ~TEST8;
897 snprintf(statstr, NTP_MAXSTRLEN, "cook %x ts %u fs %u",
898 peer->pcookie, ntohl(ep->tstamp),
900 record_crypto_stats(&peer->srcadr, statstr);
903 printf("crypto_recv: %s\n", statstr);
908 * Install autokey values in broadcast client and
909 * symmetric modes. We have to do this every time the
910 * sever/peer cookie changes or a new keylist is
911 * rolled. Ordinarily, this is automatic as this message
912 * is piggybacked on the first NTP packet sent upon
913 * either of these events. Note that a broadcast client
914 * or symmetric peer can receive this response without a
917 case CRYPTO_AUTO | CRYPTO_RESP:
920 * Discard the message if invalid or identity
921 * not confirmed or signature not verified with
922 * respect to the receive autokey values.
924 if (!(peer->crypto & CRYPTO_FLAG_VRFY)) {
928 if ((rval = crypto_verify(ep, &peer->recval,
933 * Install autokey values and light the
934 * autokey bit. This is not hard.
936 if (peer->recval.ptr == NULL)
938 emalloc(sizeof(struct autokey));
939 bp = (struct autokey *)peer->recval.ptr;
940 peer->recval.tstamp = ep->tstamp;
941 peer->recval.fstamp = ep->fstamp;
942 ap = (struct autokey *)ep->pkt;
943 bp->seq = ntohl(ap->seq);
944 bp->key = ntohl(ap->key);
945 peer->pkeyid = bp->key;
946 peer->crypto |= CRYPTO_FLAG_AUTO;
947 peer->flash &= ~TEST8;
948 snprintf(statstr, NTP_MAXSTRLEN,
949 "auto seq %d key %x ts %u fs %u", bp->seq,
950 bp->key, ntohl(ep->tstamp),
952 record_crypto_stats(&peer->srcadr, statstr);
955 printf("crypto_recv: %s\n", statstr);
960 * X509 certificate sign response. Validate the
961 * certificate signed by the server and install. Later
962 * this can be provided to clients of this server in
963 * lieu of the self signed certificate in order to
964 * validate the public key.
966 case CRYPTO_SIGN | CRYPTO_RESP:
969 * Discard the message if invalid or not
972 if (!(peer->crypto & CRYPTO_FLAG_PROV)) {
976 if ((rval = crypto_verify(ep, NULL, peer)) !=
981 * Scan the certificate list to delete old
982 * versions and link the newest version first on
985 if ((rval = cert_install(ep, peer)) != XEVNT_OK)
988 peer->crypto |= CRYPTO_FLAG_SIGN;
989 peer->flash &= ~TEST8;
991 snprintf(statstr, NTP_MAXSTRLEN,
992 "sign %s 0x%x %s (%u) fs %u",
993 cinfo->issuer, cinfo->flags,
994 OBJ_nid2ln(temp32), temp32,
996 record_crypto_stats(&peer->srcadr, statstr);
999 printf("crypto_recv: %s\n", statstr);
1004 * Install leapseconds table in symmetric modes. This
1005 * table is proventicated to the NIST primary servers,
1006 * either by copying the file containing the table from
1007 * a NIST server to a trusted server or directly using
1008 * this protocol. While the entire table is installed at
1009 * the server, presently only the current TAI offset is
1010 * provided via the kernel to other applications.
1015 * Discard the message if invalid.
1017 if ((rval = crypto_verify(ep, NULL, peer)) !=
1022 * Pass the extension field to the transmit
1023 * side. Continue below if a leapseconds table
1024 * accompanies the message.
1027 memcpy(fp, ep, len);
1028 temp32 = CRYPTO_RESP;
1029 fp->opcode |= htonl(temp32);
1031 if (len <= VALUE_LEN) {
1032 peer->flash &= ~TEST8;
1037 case CRYPTO_TAI | CRYPTO_RESP:
1040 * If this is a response, discard the message if
1041 * signature not verified with respect to the
1042 * leapsecond table values.
1044 if (peer->cmmd == NULL) {
1045 if ((rval = crypto_verify(ep,
1046 &peer->tai_leap, peer)) != XEVNT_OK)
1051 * Initialize peer variables with latest update.
1053 peer->tai_leap.tstamp = ep->tstamp;
1054 peer->tai_leap.fstamp = ep->fstamp;
1055 peer->tai_leap.vallen = ep->vallen;
1058 * Install the new table if there is no stored
1059 * table or the new table is more recent than
1060 * the stored table. Since a filestamp may have
1061 * changed, recompute the signatures.
1063 if (ntohl(peer->tai_leap.fstamp) >
1064 ntohl(tai_leap.fstamp)) {
1065 tai_leap.fstamp = ep->fstamp;
1066 tai_leap.vallen = ep->vallen;
1067 if (tai_leap.ptr != NULL)
1069 tai_leap.ptr = emalloc(vallen);
1070 memcpy(tai_leap.ptr, ep->pkt, vallen);
1073 crypto_flags |= CRYPTO_FLAG_TAI;
1074 peer->crypto |= CRYPTO_FLAG_LEAP;
1075 peer->flash &= ~TEST8;
1076 snprintf(statstr, NTP_MAXSTRLEN,
1077 "leap %u ts %u fs %u", vallen,
1078 ntohl(ep->tstamp), ntohl(ep->fstamp));
1079 record_crypto_stats(&peer->srcadr, statstr);
1082 printf("crypto_recv: %s\n", statstr);
1087 * We come here in symmetric modes for miscellaneous
1088 * commands that have value fields but are processed on
1089 * the transmit side. All we need do here is check for
1090 * valid field length. Remaining checks are below and on
1091 * the transmit side.
1098 if (len < VALUE_LEN) {
1105 * We come here for miscellaneous requests and unknown
1106 * requests and responses. If an unknown response or
1107 * error, forget it. If a request, save the extension
1108 * field for later. Unknown requests will be caught on
1109 * the transmit side.
1112 if (code & (CRYPTO_RESP | CRYPTO_ERROR)) {
1114 } else if ((rval = crypto_verify(ep, NULL,
1115 peer)) == XEVNT_OK) {
1117 memcpy(fp, ep, len);
1118 temp32 = CRYPTO_RESP;
1119 fp->opcode |= htonl(temp32);
1125 * We don't log length/format/timestamp errors and
1126 * duplicates, which are log clogging vulnerabilities.
1127 * The first error found terminates the extension field
1128 * scan and we return the laundry to the caller. A
1129 * length/format/timestamp error on transmit is
1130 * cheerfully ignored, as the message is not sent.
1132 if (rval > XEVNT_TSP) {
1133 snprintf(statstr, NTP_MAXSTRLEN,
1134 "error %x opcode %x ts %u fs %u", rval,
1135 code, tstamp, fstamp);
1136 record_crypto_stats(&peer->srcadr, statstr);
1137 report_event(rval, peer);
1140 printf("crypto_recv: %s\n", statstr);
1144 } else if (rval > XEVNT_OK && (code & CRYPTO_RESP)) {
1154 * crypto_xmit - construct extension fields
1156 * This routine is called both when an association is configured and
1157 * when one is not. The only case where this matters is to retrieve the
1158 * autokey information, in which case the caller has to provide the
1159 * association ID to match the association.
1161 * Returns length of extension field.
1165 struct pkt *xpkt, /* transmit packet pointer */
1166 struct sockaddr_storage *srcadr_sin, /* active runway */
1167 int start, /* offset to extension field */
1168 struct exten *ep, /* extension pointer */
1169 keyid_t cookie /* session cookie */
1172 u_int32 *pkt; /* packet pointer */
1173 struct peer *peer; /* peer structure pointer */
1174 u_int opcode; /* extension field opcode */
1175 struct exten *fp; /* extension pointers */
1176 struct cert_info *cp, *xp; /* certificate info/value pointer */
1177 char certname[MAXHOSTNAME + 1]; /* subject name buffer */
1178 char statstr[NTP_MAXSTRLEN]; /* statistics for filegen */
1188 * Generate the requested extension field request code, length
1189 * and association ID. If this is a response and the host is not
1190 * synchronized, light the error bit and go home.
1192 pkt = (u_int32 *)xpkt + start / 4;
1193 fp = (struct exten *)pkt;
1194 opcode = ntohl(ep->opcode);
1195 associd = (associd_t) ntohl(ep->associd);
1196 fp->associd = htonl(associd);
1199 tstamp = crypto_time();
1200 switch (opcode & 0xffff0000) {
1203 * Send association request and response with status word and
1204 * host name. Note, this message is not signed and the filestamp
1205 * contains only the status word.
1207 case CRYPTO_ASSOC | CRYPTO_RESP:
1208 len += crypto_send(fp, &hostval);
1209 fp->fstamp = htonl(crypto_flags);
1213 len += crypto_send(fp, &hostval);
1214 fp->fstamp = htonl(crypto_flags | ident_scheme);
1218 * Send certificate request. Use the values from the extension
1222 memset(&vtemp, 0, sizeof(vtemp));
1223 vtemp.tstamp = ep->tstamp;
1224 vtemp.fstamp = ep->fstamp;
1225 vtemp.vallen = ep->vallen;
1226 vtemp.ptr = (u_char *)ep->pkt;
1227 len += crypto_send(fp, &vtemp);
1231 * Send certificate response or sign request. Use the values
1232 * from the certificate cache. If the request contains no
1233 * subject name, assume the name of this host. This is for
1234 * backwards compatibility. Private certificates are never sent.
1237 case CRYPTO_CERT | CRYPTO_RESP:
1238 vallen = ntohl(ep->vallen);
1240 strcpy(certname, sys_hostname);
1241 } else if (vallen == 0 || vallen > MAXHOSTNAME) {
1246 memcpy(certname, ep->pkt, vallen);
1247 certname[vallen] = '\0';
1251 * Find all certificates with matching subject. If a
1252 * self-signed, trusted certificate is found, use that.
1253 * If not, use the first one with matching subject. A
1254 * private certificate is never divulged or signed.
1257 for (cp = cinfo; cp != NULL; cp = cp->link) {
1258 if (cp->flags & CERT_PRIV)
1261 if (strcmp(certname, cp->subject) == 0) {
1264 if (strcmp(certname, cp->issuer) ==
1265 0 && cp->flags & CERT_TRUST) {
1273 * Be careful who you trust. If not yet synchronized,
1274 * give back an empty response. If certificate not found
1275 * or beyond the lifetime, return an error. This is to
1276 * avoid a bad dude trying to get an expired certificate
1277 * re-signed. Otherwise, send it.
1279 * Note the timestamp and filestamp are taken from the
1280 * certificate value structure. For all certificates the
1281 * timestamp is the latest signature update time. For
1282 * host and imported certificates the filestamp is the
1283 * creation epoch. For signed certificates the filestamp
1284 * is the creation epoch of the trusted certificate at
1285 * the base of the certificate trail. In principle, this
1286 * allows strong checking for signature masquerade.
1293 else if (tstamp < xp->first || tstamp > xp->last)
1296 len += crypto_send(fp, &xp->cert);
1300 * Send challenge in Schnorr (IFF) identity scheme.
1303 if ((peer = findpeerbyassoc(ep->pkt[0])) == NULL) {
1307 if ((rval = crypto_alice(peer, &vtemp)) == XEVNT_OK) {
1308 len += crypto_send(fp, &vtemp);
1314 * Send response in Schnorr (IFF) identity scheme.
1316 case CRYPTO_IFF | CRYPTO_RESP:
1317 if ((rval = crypto_bob(ep, &vtemp)) == XEVNT_OK) {
1318 len += crypto_send(fp, &vtemp);
1324 * Send challenge in Guillou-Quisquater (GQ) identity scheme.
1327 if ((peer = findpeerbyassoc(ep->pkt[0])) == NULL) {
1331 if ((rval = crypto_alice2(peer, &vtemp)) == XEVNT_OK) {
1332 len += crypto_send(fp, &vtemp);
1338 * Send response in Guillou-Quisquater (GQ) identity scheme.
1340 case CRYPTO_GQ | CRYPTO_RESP:
1341 if ((rval = crypto_bob2(ep, &vtemp)) == XEVNT_OK) {
1342 len += crypto_send(fp, &vtemp);
1348 * Send challenge in MV identity scheme.
1351 if ((peer = findpeerbyassoc(ep->pkt[0])) == NULL) {
1355 if ((rval = crypto_alice3(peer, &vtemp)) == XEVNT_OK) {
1356 len += crypto_send(fp, &vtemp);
1362 * Send response in MV identity scheme.
1364 case CRYPTO_MV | CRYPTO_RESP:
1365 if ((rval = crypto_bob3(ep, &vtemp)) == XEVNT_OK) {
1366 len += crypto_send(fp, &vtemp);
1372 * Send certificate sign response. The integrity of the request
1373 * certificate has already been verified on the receive side.
1374 * Sign the response using the local server key. Use the
1375 * filestamp from the request and use the timestamp as the
1376 * current time. Light the error bit if the certificate is
1377 * invalid or contains an unverified signature.
1379 case CRYPTO_SIGN | CRYPTO_RESP:
1380 if ((rval = cert_sign(ep, &vtemp)) == XEVNT_OK)
1381 len += crypto_send(fp, &vtemp);
1386 * Send public key and signature. Use the values from the public
1390 len += crypto_send(fp, &pubkey);
1394 * Encrypt and send cookie and signature. Light the error bit if
1395 * anything goes wrong.
1397 case CRYPTO_COOK | CRYPTO_RESP:
1398 if ((opcode & 0xffff) < VALUE_LEN) {
1402 if (PKT_MODE(xpkt->li_vn_mode) == MODE_SERVER) {
1405 if ((peer = findpeerbyassoc(associd)) == NULL) {
1409 tcookie = peer->pcookie;
1411 if ((rval = crypto_encrypt(ep, &vtemp, &tcookie)) ==
1413 len += crypto_send(fp, &vtemp);
1418 * Find peer and send autokey data and signature in broadcast
1419 * server and symmetric modes. Use the values in the autokey
1420 * structure. If no association is found, either the server has
1421 * restarted with new associations or some perp has replayed an
1422 * old message, in which case light the error bit.
1424 case CRYPTO_AUTO | CRYPTO_RESP:
1425 if ((peer = findpeerbyassoc(associd)) == NULL) {
1429 peer->flags &= ~FLAG_ASSOC;
1430 len += crypto_send(fp, &peer->sndval);
1434 * Send leapseconds table and signature. Use the values from the
1435 * tai structure. If no table has been loaded, just send an
1439 case CRYPTO_TAI | CRYPTO_RESP:
1440 if (crypto_flags & CRYPTO_FLAG_TAI)
1441 len += crypto_send(fp, &tai_leap);
1445 * Default - Fall through for requests; for unknown responses,
1449 if (opcode & CRYPTO_RESP)
1454 * In case of error, flame the log. If a request, toss the
1455 * puppy; if a response, return so the sender can flame, too.
1457 if (rval != XEVNT_OK) {
1458 opcode |= CRYPTO_ERROR;
1459 snprintf(statstr, NTP_MAXSTRLEN,
1460 "error %x opcode %x", rval, opcode);
1461 record_crypto_stats(srcadr_sin, statstr);
1462 report_event(rval, NULL);
1465 printf("crypto_xmit: %s\n", statstr);
1467 if (!(opcode & CRYPTO_RESP))
1472 * Round up the field length to a multiple of 8 bytes and save
1473 * the request code and length.
1475 len = ((len + 7) / 8) * 8;
1476 fp->opcode = htonl((opcode & 0xffff0000) | len);
1480 "crypto_xmit: flags 0x%x ext offset %d len %u code 0x%x assocID %d\n",
1481 crypto_flags, start, len, opcode >> 16, associd);
1488 * crypto_verify - parse and verify the extension field and value
1492 * XEVNT_LEN bad field format or length
1493 * XEVNT_TSP bad timestamp
1494 * XEVNT_FSP bad filestamp
1495 * XEVNT_PUB bad or missing public key
1496 * XEVNT_SGL bad signature length
1497 * XEVNT_SIG signature not verified
1498 * XEVNT_ERR protocol error
1502 struct exten *ep, /* extension pointer */
1503 struct value *vp, /* value pointer */
1504 struct peer *peer /* peer structure pointer */
1507 EVP_PKEY *pkey; /* server public key */
1508 EVP_MD_CTX ctx; /* signature context */
1509 tstamp_t tstamp, tstamp1 = 0; /* timestamp */
1510 tstamp_t fstamp, fstamp1 = 0; /* filestamp */
1511 u_int vallen; /* value length */
1512 u_int siglen; /* signature length */
1517 * We require valid opcode and field lengths, timestamp,
1518 * filestamp, public key, digest, signature length and
1519 * signature, where relevant. Note that preliminary length
1520 * checks are done in the main loop.
1522 len = ntohl(ep->opcode) & 0x0000ffff;
1523 opcode = ntohl(ep->opcode) & 0xffff0000;
1526 * Check for valid operation code and protocol. The opcode must
1527 * not have the error bit set. If a response, it must have a
1528 * value header. If a request and does not contain a value
1529 * header, no need for further checking.
1531 if (opcode & CRYPTO_ERROR)
1534 if (opcode & CRYPTO_RESP) {
1535 if (len < VALUE_LEN)
1538 if (len < VALUE_LEN)
1543 * We have a value header. Check for valid field lengths. The
1544 * field length must be long enough to contain the value header,
1545 * value and signature. Note both the value and signature fields
1546 * are rounded up to the next word.
1548 vallen = ntohl(ep->vallen);
1549 i = (vallen + 3) / 4;
1550 siglen = ntohl(ep->pkt[i++]);
1551 if (len < VALUE_LEN + ((vallen + 3) / 4) * 4 + ((siglen + 3) /
1556 * Punt if this is a response with no data. Punt if this is a
1557 * request and a previous response is pending.
1559 if (opcode & CRYPTO_RESP) {
1563 if (peer->cmmd != NULL)
1568 * Check for valid timestamp and filestamp. If the timestamp is
1569 * zero, the sender is not synchronized and signatures are
1570 * disregarded. If not, the timestamp must not precede the
1571 * filestamp. The timestamp and filestamp must not precede the
1572 * corresponding values in the value structure, if present. Once
1573 * the autokey values have been installed, the timestamp must
1574 * always be later than the corresponding value in the value
1575 * structure. Duplicate timestamps are illegal once the cookie
1576 * has been validated.
1578 tstamp = ntohl(ep->tstamp);
1579 fstamp = ntohl(ep->fstamp);
1583 if (tstamp < fstamp)
1587 tstamp1 = ntohl(vp->tstamp);
1588 fstamp1 = ntohl(vp->fstamp);
1589 if ((tstamp < tstamp1 || (tstamp == tstamp1 &&
1590 (peer->crypto & CRYPTO_FLAG_AUTO))))
1593 if ((tstamp < fstamp1 || fstamp < fstamp1))
1598 * Check for valid signature length, public key and digest
1601 if (crypto_flags & peer->crypto & CRYPTO_FLAG_PRIV)
1605 if (siglen == 0 || pkey == NULL || peer->digest == NULL)
1608 if (siglen != (u_int)EVP_PKEY_size(pkey))
1612 * Darn, I thought we would never get here. Verify the
1613 * signature. If the identity exchange is verified, light the
1614 * proventic bit. If no client identity scheme is specified,
1615 * avoid doing the sign exchange.
1617 EVP_VerifyInit(&ctx, peer->digest);
1618 EVP_VerifyUpdate(&ctx, (u_char *)&ep->tstamp, vallen + 12);
1619 if (EVP_VerifyFinal(&ctx, (u_char *)&ep->pkt[i], siglen, pkey) <= 0)
1622 if (peer->crypto & CRYPTO_FLAG_VRFY) {
1623 peer->crypto |= CRYPTO_FLAG_PROV;
1624 if (!(crypto_flags & CRYPTO_FLAG_MASK))
1625 peer->crypto |= CRYPTO_FLAG_SIGN;
1632 * crypto_encrypt - construct encrypted cookie and signature from
1633 * extension field and cookie
1637 * XEVNT_PUB bad or missing public key
1638 * XEVNT_CKY bad or missing cookie
1639 * XEVNT_PER host certificate expired
1643 struct exten *ep, /* extension pointer */
1644 struct value *vp, /* value pointer */
1645 keyid_t *cookie /* server cookie */
1648 EVP_PKEY *pkey; /* public key */
1649 EVP_MD_CTX ctx; /* signature context */
1650 tstamp_t tstamp; /* NTP timestamp */
1656 * Extract the public key from the request.
1658 len = ntohl(ep->vallen);
1659 ptr = (u_char *)ep->pkt;
1660 pkey = d2i_PublicKey(EVP_PKEY_RSA, NULL, &ptr, len);
1662 msyslog(LOG_ERR, "crypto_encrypt %s\n",
1663 ERR_error_string(ERR_get_error(), NULL));
1668 * Encrypt the cookie, encode in ASN.1 and sign.
1670 tstamp = crypto_time();
1671 memset(vp, 0, sizeof(struct value));
1672 vp->tstamp = htonl(tstamp);
1673 vp->fstamp = hostval.tstamp;
1674 len = EVP_PKEY_size(pkey);
1675 vp->vallen = htonl(len);
1676 vp->ptr = emalloc(len);
1677 temp32 = htonl(*cookie);
1678 if (!RSA_public_encrypt(4, (u_char *)&temp32, vp->ptr,
1679 pkey->pkey.rsa, RSA_PKCS1_OAEP_PADDING)) {
1680 msyslog(LOG_ERR, "crypto_encrypt %s\n",
1681 ERR_error_string(ERR_get_error(), NULL));
1682 EVP_PKEY_free(pkey);
1685 EVP_PKEY_free(pkey);
1690 if (tstamp < cinfo->first || tstamp > cinfo->last)
1693 vp->sig = emalloc(sign_siglen);
1694 EVP_SignInit(&ctx, sign_digest);
1695 EVP_SignUpdate(&ctx, (u_char *)&vp->tstamp, 12);
1696 EVP_SignUpdate(&ctx, vp->ptr, len);
1697 if (EVP_SignFinal(&ctx, vp->sig, &len, sign_pkey))
1698 vp->siglen = htonl(len);
1704 * crypto_ident - construct extension field for identity scheme
1706 * This routine determines which identity scheme is in use and
1707 * constructs an extension field for that scheme.
1711 struct peer *peer /* peer structure pointer */
1714 char filename[MAXFILENAME + 1];
1717 * If the server identity has already been verified, no further
1718 * action is necessary. Otherwise, try to load the identity file
1719 * of the certificate issuer. If the issuer file is not found,
1720 * try the host file. If nothing found, declare a cryptobust.
1721 * Note we can't get here unless the trusted certificate has
1722 * been found and the CRYPTO_FLAG_VALID bit is set, so the
1723 * certificate issuer is valid.
1725 if (peer->ident_pkey != NULL)
1726 EVP_PKEY_free(peer->ident_pkey);
1727 if (peer->crypto & CRYPTO_FLAG_GQ) {
1728 snprintf(filename, MAXFILENAME, "ntpkey_gq_%s",
1730 peer->ident_pkey = crypto_key(filename, &peer->fstamp);
1731 if (peer->ident_pkey != NULL)
1734 snprintf(filename, MAXFILENAME, "ntpkey_gq_%s",
1736 peer->ident_pkey = crypto_key(filename, &peer->fstamp);
1737 if (peer->ident_pkey != NULL)
1740 if (peer->crypto & CRYPTO_FLAG_IFF) {
1741 snprintf(filename, MAXFILENAME, "ntpkey_iff_%s",
1743 peer->ident_pkey = crypto_key(filename, &peer->fstamp);
1744 if (peer->ident_pkey != NULL)
1745 return (CRYPTO_IFF);
1747 snprintf(filename, MAXFILENAME, "ntpkey_iff_%s",
1749 peer->ident_pkey = crypto_key(filename, &peer->fstamp);
1750 if (peer->ident_pkey != NULL)
1751 return (CRYPTO_IFF);
1753 if (peer->crypto & CRYPTO_FLAG_MV) {
1754 snprintf(filename, MAXFILENAME, "ntpkey_mv_%s",
1756 peer->ident_pkey = crypto_key(filename, &peer->fstamp);
1757 if (peer->ident_pkey != NULL)
1760 snprintf(filename, MAXFILENAME, "ntpkey_mv_%s",
1762 peer->ident_pkey = crypto_key(filename, &peer->fstamp);
1763 if (peer->ident_pkey != NULL)
1768 * No compatible identity scheme is available. Life is hard.
1771 "crypto_ident: no compatible identity scheme found");
1777 * crypto_args - construct extension field from arguments
1779 * This routine creates an extension field with current timestamps and
1780 * specified opcode, association ID and optional string. Note that the
1781 * extension field is created here, but freed after the crypto_xmit()
1782 * call in the protocol module.
1784 * Returns extension field pointer (no errors).
1788 struct peer *peer, /* peer structure pointer */
1789 u_int opcode, /* operation code */
1790 char *str /* argument string */
1793 tstamp_t tstamp; /* NTP timestamp */
1794 struct exten *ep; /* extension field pointer */
1795 u_int len; /* extension field length */
1797 tstamp = crypto_time();
1798 len = sizeof(struct exten);
1806 ep->opcode = htonl(opcode + len);
1809 * If a response, send our ID; if a request, send the
1812 if (opcode & CRYPTO_RESP)
1813 ep->associd = htonl(peer->associd);
1815 ep->associd = htonl(peer->assoc);
1816 ep->tstamp = htonl(tstamp);
1817 ep->fstamp = hostval.tstamp;
1820 ep->vallen = htonl(strlen(str));
1821 memcpy((char *)ep->pkt, str, strlen(str));
1823 ep->pkt[0] = peer->associd;
1830 * crypto_send - construct extension field from value components
1832 * Returns extension field length. Note: it is not polite to send a
1833 * nonempty signature with zero timestamp or a nonzero timestamp with
1834 * empty signature, but these rules are not enforced here.
1838 struct exten *ep, /* extension field pointer */
1839 struct value *vp /* value pointer */
1846 * Copy data. If the data field is empty or zero length, encode
1847 * an empty value with length zero.
1849 ep->tstamp = vp->tstamp;
1850 ep->fstamp = vp->fstamp;
1851 ep->vallen = vp->vallen;
1853 temp32 = ntohl(vp->vallen);
1854 if (temp32 > 0 && vp->ptr != NULL)
1855 memcpy(ep->pkt, vp->ptr, temp32);
1858 * Copy signature. If the signature field is empty or zero
1859 * length, encode an empty signature with length zero.
1861 i = (temp32 + 3) / 4;
1863 ep->pkt[i++] = vp->siglen;
1864 temp32 = ntohl(vp->siglen);
1865 if (temp32 > 0 && vp->sig != NULL)
1866 memcpy(&ep->pkt[i], vp->sig, temp32);
1873 * crypto_update - compute new public value and sign extension fields
1875 * This routine runs periodically, like once a day, and when something
1876 * changes. It updates the timestamps on three value structures and one
1877 * value structure list, then signs all the structures:
1879 * hostval host name (not signed)
1881 * cinfo certificate info/value list
1882 * tai_leap leapseconds file
1884 * Filestamps are proventicated data, so this routine is run only when
1885 * the host has been synchronized to a proventicated source. Thus, the
1886 * timestamp is proventicated, too, and can be used to deflect
1887 * clogging attacks and even cook breakfast.
1889 * Returns void (no errors)
1894 EVP_MD_CTX ctx; /* message digest context */
1895 struct cert_info *cp, *cpn; /* certificate info/value */
1896 char statstr[NTP_MAXSTRLEN]; /* statistics for filegen */
1897 tstamp_t tstamp; /* NTP timestamp */
1900 if ((tstamp = crypto_time()) == 0)
1903 hostval.tstamp = htonl(tstamp);
1906 * Sign public key and timestamps. The filestamp is derived from
1907 * the host key file extension from wherever the file was
1910 if (pubkey.vallen != 0) {
1911 pubkey.tstamp = hostval.tstamp;
1913 if (pubkey.sig == NULL)
1914 pubkey.sig = emalloc(sign_siglen);
1915 EVP_SignInit(&ctx, sign_digest);
1916 EVP_SignUpdate(&ctx, (u_char *)&pubkey, 12);
1917 EVP_SignUpdate(&ctx, pubkey.ptr, ntohl(pubkey.vallen));
1918 if (EVP_SignFinal(&ctx, pubkey.sig, &len, sign_pkey))
1919 pubkey.siglen = htonl(len);
1923 * Sign certificates and timestamps. The filestamp is derived
1924 * from the certificate file extension from wherever the file
1925 * was generated. Note we do not throw expired certificates
1926 * away; they may have signed younger ones.
1928 for (cp = cinfo; cp != NULL; cp = cpn) {
1930 cp->cert.tstamp = hostval.tstamp;
1931 cp->cert.siglen = 0;
1932 if (cp->cert.sig == NULL)
1933 cp->cert.sig = emalloc(sign_siglen);
1934 EVP_SignInit(&ctx, sign_digest);
1935 EVP_SignUpdate(&ctx, (u_char *)&cp->cert, 12);
1936 EVP_SignUpdate(&ctx, cp->cert.ptr,
1937 ntohl(cp->cert.vallen));
1938 if (EVP_SignFinal(&ctx, cp->cert.sig, &len, sign_pkey))
1939 cp->cert.siglen = htonl(len);
1943 * Sign leapseconds table and timestamps. The filestamp is
1944 * derived from the leapsecond file extension from wherever the
1945 * file was generated.
1947 if (tai_leap.vallen != 0) {
1948 tai_leap.tstamp = hostval.tstamp;
1949 tai_leap.siglen = 0;
1950 if (tai_leap.sig == NULL)
1951 tai_leap.sig = emalloc(sign_siglen);
1952 EVP_SignInit(&ctx, sign_digest);
1953 EVP_SignUpdate(&ctx, (u_char *)&tai_leap, 12);
1954 EVP_SignUpdate(&ctx, tai_leap.ptr,
1955 ntohl(tai_leap.vallen));
1956 if (EVP_SignFinal(&ctx, tai_leap.sig, &len, sign_pkey))
1957 tai_leap.siglen = htonl(len);
1959 snprintf(statstr, NTP_MAXSTRLEN,
1960 "update ts %u", ntohl(hostval.tstamp));
1961 record_crypto_stats(NULL, statstr);
1964 printf("crypto_update: %s\n", statstr);
1970 * value_free - free value structure components.
1972 * Returns void (no errors)
1976 struct value *vp /* value structure */
1979 if (vp->ptr != NULL)
1981 if (vp->sig != NULL)
1983 memset(vp, 0, sizeof(struct value));
1988 * crypto_time - returns current NTP time in seconds.
1993 l_fp tstamp; /* NTP time */ L_CLR(&tstamp);
1996 if (sys_leap != LEAP_NOTINSYNC)
1997 get_systime(&tstamp);
1998 return (tstamp.l_ui);
2003 * asn2ntp - convert ASN1_TIME time structure to NTP time in seconds.
2007 ASN1_TIME *asn1time /* pointer to ASN1_TIME structure */
2010 char *v; /* pointer to ASN1_TIME string */
2011 struct tm tm; /* used to convert to NTP time */
2014 * Extract time string YYMMDDHHMMSSZ from ASN1 time structure.
2015 * Note that the YY, MM, DD fields start with one, the HH, MM,
2016 * SS fiels start with zero and the Z character should be 'Z'
2017 * for UTC. Also note that years less than 50 map to years
2018 * greater than 100. Dontcha love ASN.1? Better than MIL-188.
2020 if (asn1time->length > 13)
2021 return ((u_long)(~0)); /* We can't use -1 here. It's invalid */
2023 v = (char *)asn1time->data;
2024 tm.tm_year = (v[0] - '0') * 10 + v[1] - '0';
2025 if (tm.tm_year < 50)
2027 tm.tm_mon = (v[2] - '0') * 10 + v[3] - '0' - 1;
2028 tm.tm_mday = (v[4] - '0') * 10 + v[5] - '0';
2029 tm.tm_hour = (v[6] - '0') * 10 + v[7] - '0';
2030 tm.tm_min = (v[8] - '0') * 10 + v[9] - '0';
2031 tm.tm_sec = (v[10] - '0') * 10 + v[11] - '0';
2035 return (timegm(&tm) + JAN_1970);
2040 * bigdig() - compute a BIGNUM MD5 hash of a BIGNUM number.
2044 BIGNUM *bn, /* BIGNUM * from */
2045 BIGNUM *bk /* BIGNUM * to */
2048 EVP_MD_CTX ctx; /* message digest context */
2049 u_char dgst[EVP_MAX_MD_SIZE]; /* message digest */
2050 u_char *ptr; /* a BIGNUM as binary string */
2053 len = BN_num_bytes(bn);
2056 EVP_DigestInit(&ctx, EVP_md5());
2057 EVP_DigestUpdate(&ctx, ptr, len);
2058 EVP_DigestFinal(&ctx, dgst, &len);
2059 BN_bin2bn(dgst, len, bk);
2061 /* XXX MEMLEAK? free ptr? */
2068 ***********************************************************************
2070 * The following routines implement the Schnorr (IFF) identity scheme *
2072 ***********************************************************************
2074 * The Schnorr (IFF) identity scheme is intended for use when
2075 * the ntp-genkeys program does not generate the certificates used in
2076 * the protocol and the group key cannot be conveyed in the certificate
2077 * itself. For this purpose, new generations of IFF values must be
2078 * securely transmitted to all members of the group before use. The
2079 * scheme is self contained and independent of new generations of host
2080 * keys, sign keys and certificates.
2082 * The IFF identity scheme is based on DSA cryptography and algorithms
2083 * described in Stinson p. 285. The IFF values hide in a DSA cuckoo
2084 * structure, but only the primes and generator are used. The p is a
2085 * 512-bit prime, q a 160-bit prime that divides p - 1 and is a qth root
2086 * of 1 mod p; that is, g^q = 1 mod p. The TA rolls primvate random
2087 * group key b disguised as a DSA structure member, then computes public
2088 * key g^(q - b). These values are shared only among group members and
2089 * never revealed in messages. Alice challenges Bob to confirm identity
2090 * using the protocol described below.
2094 * The scheme goes like this. Both Alice and Bob have the public primes
2095 * p, q and generator g. The TA gives private key b to Bob and public
2096 * key v = g^(q - a) mod p to Alice.
2098 * Alice rolls new random challenge r and sends to Bob in the IFF
2099 * request message. Bob rolls new random k, then computes y = k + b r
2100 * mod q and x = g^k mod p and sends (y, hash(x)) to Alice in the
2101 * response message. Besides making the response shorter, the hash makes
2102 * it effectivey impossible for an intruder to solve for b by observing
2103 * a number of these messages.
2105 * Alice receives the response and computes g^y v^r mod p. After a bit
2106 * of algebra, this simplifies to g^k. If the hash of this result
2107 * matches hash(x), Alice knows that Bob has the group key b. The signed
2108 * response binds this knowledge to Bob's private key and the public key
2109 * previously received in his certificate.
2111 * crypto_alice - construct Alice's challenge in IFF scheme
2115 * XEVNT_PUB bad or missing public key
2116 * XEVNT_ID bad or missing group key
2120 struct peer *peer, /* peer pointer */
2121 struct value *vp /* value pointer */
2124 DSA *dsa; /* IFF parameters */
2125 BN_CTX *bctx; /* BIGNUM context */
2126 EVP_MD_CTX ctx; /* signature context */
2131 * The identity parameters must have correct format and content.
2133 if (peer->ident_pkey == NULL)
2136 if ((dsa = peer->ident_pkey->pkey.dsa) == NULL) {
2137 msyslog(LOG_INFO, "crypto_alice: defective key");
2142 * Roll new random r (0 < r < q). The OpenSSL library has a bug
2143 * omitting BN_rand_range, so we have to do it the hard way.
2145 bctx = BN_CTX_new();
2146 len = BN_num_bytes(dsa->q);
2147 if (peer->iffval != NULL)
2148 BN_free(peer->iffval);
2149 peer->iffval = BN_new();
2150 BN_rand(peer->iffval, len * 8, -1, 1); /* r */
2151 BN_mod(peer->iffval, peer->iffval, dsa->q, bctx);
2155 * Sign and send to Bob. The filestamp is from the local file.
2157 tstamp = crypto_time();
2158 memset(vp, 0, sizeof(struct value));
2159 vp->tstamp = htonl(tstamp);
2160 vp->fstamp = htonl(peer->fstamp);
2161 vp->vallen = htonl(len);
2162 vp->ptr = emalloc(len);
2163 BN_bn2bin(peer->iffval, vp->ptr);
2168 if (tstamp < cinfo->first || tstamp > cinfo->last)
2171 vp->sig = emalloc(sign_siglen);
2172 EVP_SignInit(&ctx, sign_digest);
2173 EVP_SignUpdate(&ctx, (u_char *)&vp->tstamp, 12);
2174 EVP_SignUpdate(&ctx, vp->ptr, len);
2175 if (EVP_SignFinal(&ctx, vp->sig, &len, sign_pkey))
2176 vp->siglen = htonl(len);
2182 * crypto_bob - construct Bob's response to Alice's challenge
2186 * XEVNT_ID bad or missing group key
2187 * XEVNT_ERR protocol error
2188 * XEVNT_PER host expired certificate
2192 struct exten *ep, /* extension pointer */
2193 struct value *vp /* value pointer */
2196 DSA *dsa; /* IFF parameters */
2197 DSA_SIG *sdsa; /* DSA signature context fake */
2198 BN_CTX *bctx; /* BIGNUM context */
2199 EVP_MD_CTX ctx; /* signature context */
2200 tstamp_t tstamp; /* NTP timestamp */
2201 BIGNUM *bn, *bk, *r;
2206 * If the IFF parameters are not valid, something awful
2207 * happened or we are being tormented.
2209 if (iffpar_pkey == NULL) {
2210 msyslog(LOG_INFO, "crypto_bob: scheme unavailable");
2213 dsa = iffpar_pkey->pkey.dsa;
2216 * Extract r from the challenge.
2218 len = ntohl(ep->vallen);
2219 if ((r = BN_bin2bn((u_char *)ep->pkt, len, NULL)) == NULL) {
2220 msyslog(LOG_ERR, "crypto_bob %s\n",
2221 ERR_error_string(ERR_get_error(), NULL));
2226 * Bob rolls random k (0 < k < q), computes y = k + b r mod q
2227 * and x = g^k mod p, then sends (y, hash(x)) to Alice.
2229 bctx = BN_CTX_new(); bk = BN_new(); bn = BN_new();
2230 sdsa = DSA_SIG_new();
2231 BN_rand(bk, len * 8, -1, 1); /* k */
2232 BN_mod_mul(bn, dsa->priv_key, r, dsa->q, bctx); /* b r mod q */
2234 BN_mod(bn, bn, dsa->q, bctx); /* k + b r mod q */
2235 sdsa->r = BN_dup(bn);
2236 BN_mod_exp(bk, dsa->g, bk, dsa->p, bctx); /* g^k mod p */
2238 sdsa->s = BN_dup(bk);
2240 BN_free(r); BN_free(bn); BN_free(bk);
2243 * Encode the values in ASN.1 and sign.
2245 tstamp = crypto_time();
2246 memset(vp, 0, sizeof(struct value));
2247 vp->tstamp = htonl(tstamp);
2248 vp->fstamp = htonl(if_fstamp);
2249 len = i2d_DSA_SIG(sdsa, NULL);
2251 msyslog(LOG_ERR, "crypto_bob %s\n",
2252 ERR_error_string(ERR_get_error(), NULL));
2256 vp->vallen = htonl(len);
2259 i2d_DSA_SIG(sdsa, &ptr);
2265 if (tstamp < cinfo->first || tstamp > cinfo->last)
2268 vp->sig = emalloc(sign_siglen);
2269 EVP_SignInit(&ctx, sign_digest);
2270 EVP_SignUpdate(&ctx, (u_char *)&vp->tstamp, 12);
2271 EVP_SignUpdate(&ctx, vp->ptr, len);
2272 if (EVP_SignFinal(&ctx, vp->sig, &len, sign_pkey))
2273 vp->siglen = htonl(len);
2279 * crypto_iff - verify Bob's response to Alice's challenge
2283 * XEVNT_PUB bad or missing public key
2284 * XEVNT_ID bad or missing group key
2285 * XEVNT_FSP bad filestamp
2289 struct exten *ep, /* extension pointer */
2290 struct peer *peer /* peer structure pointer */
2293 DSA *dsa; /* IFF parameters */
2294 BN_CTX *bctx; /* BIGNUM context */
2295 DSA_SIG *sdsa; /* DSA parameters */
2302 * If the IFF parameters are not valid or no challenge was sent,
2303 * something awful happened or we are being tormented.
2305 if (peer->ident_pkey == NULL) {
2306 msyslog(LOG_INFO, "crypto_iff: scheme unavailable");
2309 if (ntohl(ep->fstamp) != peer->fstamp) {
2310 msyslog(LOG_INFO, "crypto_iff: invalid filestamp %u",
2314 if ((dsa = peer->ident_pkey->pkey.dsa) == NULL) {
2315 msyslog(LOG_INFO, "crypto_iff: defective key");
2318 if (peer->iffval == NULL) {
2319 msyslog(LOG_INFO, "crypto_iff: missing challenge");
2324 * Extract the k + b r and g^k values from the response.
2326 bctx = BN_CTX_new(); bk = BN_new(); bn = BN_new();
2327 len = ntohl(ep->vallen);
2328 ptr = (const u_char *)ep->pkt;
2329 if ((sdsa = d2i_DSA_SIG(NULL, &ptr, len)) == NULL) {
2330 msyslog(LOG_ERR, "crypto_iff %s\n",
2331 ERR_error_string(ERR_get_error(), NULL));
2336 * Compute g^(k + b r) g^(q - b)r mod p.
2338 BN_mod_exp(bn, dsa->pub_key, peer->iffval, dsa->p, bctx);
2339 BN_mod_exp(bk, dsa->g, sdsa->r, dsa->p, bctx);
2340 BN_mod_mul(bn, bn, bk, dsa->p, bctx);
2343 * Verify the hash of the result matches hash(x).
2346 temp = BN_cmp(bn, sdsa->s);
2347 BN_free(bn); BN_free(bk); BN_CTX_free(bctx);
2348 BN_free(peer->iffval);
2349 peer->iffval = NULL;
2360 ***********************************************************************
2362 * The following routines implement the Guillou-Quisquater (GQ) *
2365 ***********************************************************************
2367 * The Guillou-Quisquater (GQ) identity scheme is intended for use when
2368 * the ntp-genkeys program generates the certificates used in the
2369 * protocol and the group key can be conveyed in a certificate extension
2370 * field. The scheme is self contained and independent of new
2371 * generations of host keys, sign keys and certificates.
2373 * The GQ identity scheme is based on RSA cryptography and algorithms
2374 * described in Stinson p. 300 (with errors). The GQ values hide in a
2375 * RSA cuckoo structure, but only the modulus is used. The 512-bit
2376 * public modulus is n = p q, where p and q are secret large primes. The
2377 * TA rolls random group key b disguised as a RSA structure member.
2378 * Except for the public key, these values are shared only among group
2379 * members and never revealed in messages.
2381 * When rolling new certificates, Bob recomputes the private and
2382 * public keys. The private key u is a random roll, while the public key
2383 * is the inverse obscured by the group key v = (u^-1)^b. These values
2384 * replace the private and public keys normally generated by the RSA
2385 * scheme. Alice challenges Bob to confirm identity using the protocol
2390 * The scheme goes like this. Both Alice and Bob have the same modulus n
2391 * and some random b as the group key. These values are computed and
2392 * distributed in advance via secret means, although only the group key
2393 * b is truly secret. Each has a private random private key u and public
2394 * key (u^-1)^b, although not necessarily the same ones. Bob and Alice
2395 * can regenerate the key pair from time to time without affecting
2396 * operations. The public key is conveyed on the certificate in an
2397 * extension field; the private key is never revealed.
2399 * Alice rolls new random challenge r and sends to Bob in the GQ
2400 * request message. Bob rolls new random k, then computes y = k u^r mod
2401 * n and x = k^b mod n and sends (y, hash(x)) to Alice in the response
2402 * message. Besides making the response shorter, the hash makes it
2403 * effectivey impossible for an intruder to solve for b by observing
2404 * a number of these messages.
2406 * Alice receives the response and computes y^b v^r mod n. After a bit
2407 * of algebra, this simplifies to k^b. If the hash of this result
2408 * matches hash(x), Alice knows that Bob has the group key b. The signed
2409 * response binds this knowledge to Bob's private key and the public key
2410 * previously received in his certificate.
2412 * crypto_alice2 - construct Alice's challenge in GQ scheme
2416 * XEVNT_PUB bad or missing public key
2417 * XEVNT_ID bad or missing group key
2418 * XEVNT_PER host certificate expired
2422 struct peer *peer, /* peer pointer */
2423 struct value *vp /* value pointer */
2426 RSA *rsa; /* GQ parameters */
2427 BN_CTX *bctx; /* BIGNUM context */
2428 EVP_MD_CTX ctx; /* signature context */
2433 * The identity parameters must have correct format and content.
2435 if (peer->ident_pkey == NULL)
2438 if ((rsa = peer->ident_pkey->pkey.rsa) == NULL) {
2439 msyslog(LOG_INFO, "crypto_alice2: defective key");
2444 * Roll new random r (0 < r < n). The OpenSSL library has a bug
2445 * omitting BN_rand_range, so we have to do it the hard way.
2447 bctx = BN_CTX_new();
2448 len = BN_num_bytes(rsa->n);
2449 if (peer->iffval != NULL)
2450 BN_free(peer->iffval);
2451 peer->iffval = BN_new();
2452 BN_rand(peer->iffval, len * 8, -1, 1); /* r mod n */
2453 BN_mod(peer->iffval, peer->iffval, rsa->n, bctx);
2457 * Sign and send to Bob. The filestamp is from the local file.
2459 tstamp = crypto_time();
2460 memset(vp, 0, sizeof(struct value));
2461 vp->tstamp = htonl(tstamp);
2462 vp->fstamp = htonl(peer->fstamp);
2463 vp->vallen = htonl(len);
2464 vp->ptr = emalloc(len);
2465 BN_bn2bin(peer->iffval, vp->ptr);
2470 if (tstamp < cinfo->first || tstamp > cinfo->last)
2473 vp->sig = emalloc(sign_siglen);
2474 EVP_SignInit(&ctx, sign_digest);
2475 EVP_SignUpdate(&ctx, (u_char *)&vp->tstamp, 12);
2476 EVP_SignUpdate(&ctx, vp->ptr, len);
2477 if (EVP_SignFinal(&ctx, vp->sig, &len, sign_pkey))
2478 vp->siglen = htonl(len);
2484 * crypto_bob2 - construct Bob's response to Alice's challenge
2488 * XEVNT_ID bad or missing group key
2489 * XEVNT_ERR protocol error
2490 * XEVNT_PER host certificate expired
2494 struct exten *ep, /* extension pointer */
2495 struct value *vp /* value pointer */
2498 RSA *rsa; /* GQ parameters */
2499 DSA_SIG *sdsa; /* DSA parameters */
2500 BN_CTX *bctx; /* BIGNUM context */
2501 EVP_MD_CTX ctx; /* signature context */
2502 tstamp_t tstamp; /* NTP timestamp */
2503 BIGNUM *r, *k, *g, *y;
2508 * If the GQ parameters are not valid, something awful
2509 * happened or we are being tormented.
2511 if (gqpar_pkey == NULL) {
2512 msyslog(LOG_INFO, "crypto_bob2: scheme unavailable");
2515 rsa = gqpar_pkey->pkey.rsa;
2518 * Extract r from the challenge.
2520 len = ntohl(ep->vallen);
2521 if ((r = BN_bin2bn((u_char *)ep->pkt, len, NULL)) == NULL) {
2522 msyslog(LOG_ERR, "crypto_bob2 %s\n",
2523 ERR_error_string(ERR_get_error(), NULL));
2528 * Bob rolls random k (0 < k < n), computes y = k u^r mod n and
2529 * x = k^b mod n, then sends (y, hash(x)) to Alice.
2531 bctx = BN_CTX_new(); k = BN_new(); g = BN_new(); y = BN_new();
2532 sdsa = DSA_SIG_new();
2533 BN_rand(k, len * 8, -1, 1); /* k */
2534 BN_mod(k, k, rsa->n, bctx);
2535 BN_mod_exp(y, rsa->p, r, rsa->n, bctx); /* u^r mod n */
2536 BN_mod_mul(y, k, y, rsa->n, bctx); /* k u^r mod n */
2537 sdsa->r = BN_dup(y);
2538 BN_mod_exp(g, k, rsa->e, rsa->n, bctx); /* k^b mod n */
2540 sdsa->s = BN_dup(g);
2542 BN_free(r); BN_free(k); BN_free(g); BN_free(y);
2545 * Encode the values in ASN.1 and sign.
2547 tstamp = crypto_time();
2548 memset(vp, 0, sizeof(struct value));
2549 vp->tstamp = htonl(tstamp);
2550 vp->fstamp = htonl(gq_fstamp);
2551 len = i2d_DSA_SIG(sdsa, NULL);
2553 msyslog(LOG_ERR, "crypto_bob2 %s\n",
2554 ERR_error_string(ERR_get_error(), NULL));
2558 vp->vallen = htonl(len);
2561 i2d_DSA_SIG(sdsa, &ptr);
2567 if (tstamp < cinfo->first || tstamp > cinfo->last)
2570 vp->sig = emalloc(sign_siglen);
2571 EVP_SignInit(&ctx, sign_digest);
2572 EVP_SignUpdate(&ctx, (u_char *)&vp->tstamp, 12);
2573 EVP_SignUpdate(&ctx, vp->ptr, len);
2574 if (EVP_SignFinal(&ctx, vp->sig, &len, sign_pkey))
2575 vp->siglen = htonl(len);
2581 * crypto_gq - verify Bob's response to Alice's challenge
2585 * XEVNT_PUB bad or missing public key
2586 * XEVNT_ID bad or missing group keys
2587 * XEVNT_ERR protocol error
2588 * XEVNT_FSP bad filestamp
2592 struct exten *ep, /* extension pointer */
2593 struct peer *peer /* peer structure pointer */
2596 RSA *rsa; /* GQ parameters */
2597 BN_CTX *bctx; /* BIGNUM context */
2598 DSA_SIG *sdsa; /* RSA signature context fake */
2605 * If the GQ parameters are not valid or no challenge was sent,
2606 * something awful happened or we are being tormented.
2608 if (peer->ident_pkey == NULL) {
2609 msyslog(LOG_INFO, "crypto_gq: scheme unavailable");
2612 if (ntohl(ep->fstamp) != peer->fstamp) {
2613 msyslog(LOG_INFO, "crypto_gq: invalid filestamp %u",
2617 if ((rsa = peer->ident_pkey->pkey.rsa) == NULL) {
2618 msyslog(LOG_INFO, "crypto_gq: defective key");
2621 if (peer->iffval == NULL) {
2622 msyslog(LOG_INFO, "crypto_gq: missing challenge");
2627 * Extract the y = k u^r and hash(x = k^b) values from the
2630 bctx = BN_CTX_new(); y = BN_new(); v = BN_new();
2631 len = ntohl(ep->vallen);
2632 ptr = (const u_char *)ep->pkt;
2633 if ((sdsa = d2i_DSA_SIG(NULL, &ptr, len)) == NULL) {
2634 msyslog(LOG_ERR, "crypto_gq %s\n",
2635 ERR_error_string(ERR_get_error(), NULL));
2640 * Compute v^r y^b mod n.
2642 BN_mod_exp(v, peer->grpkey, peer->iffval, rsa->n, bctx);
2644 BN_mod_exp(y, sdsa->r, rsa->e, rsa->n, bctx); /* y^b mod n */
2645 BN_mod_mul(y, v, y, rsa->n, bctx); /* v^r y^b mod n */
2648 * Verify the hash of the result matches hash(x).
2651 temp = BN_cmp(y, sdsa->s);
2652 BN_CTX_free(bctx); BN_free(y); BN_free(v);
2653 BN_free(peer->iffval);
2654 peer->iffval = NULL;
2665 ***********************************************************************
2667 * The following routines implement the Mu-Varadharajan (MV) identity *
2670 ***********************************************************************
2673 * The Mu-Varadharajan (MV) cryptosystem was originally intended when
2674 * servers broadcast messages to clients, but clients never send
2675 * messages to servers. There is one encryption key for the server and a
2676 * separate decryption key for each client. It operated something like a
2677 * pay-per-view satellite broadcasting system where the session key is
2678 * encrypted by the broadcaster and the decryption keys are held in a
2679 * tamperproof set-top box.
2681 * The MV parameters and private encryption key hide in a DSA cuckoo
2682 * structure which uses the same parameters, but generated in a
2683 * different way. The values are used in an encryption scheme similar to
2684 * El Gamal cryptography and a polynomial formed from the expansion of
2685 * product terms (x - x[j]), as described in Mu, Y., and V.
2686 * Varadharajan: Robust and Secure Broadcasting, Proc. Indocrypt 2001,
2687 * 223-231. The paper has significant errors and serious omissions.
2689 * Let q be the product of n distinct primes s'[j] (j = 1...n), where
2690 * each s'[j] has m significant bits. Let p be a prime p = 2 * q + 1, so
2691 * that q and each s'[j] divide p - 1 and p has M = n * m + 1
2692 * significant bits. The elements x mod q of Zq with the elements 2 and
2693 * the primes removed form a field Zq* valid for polynomial arithetic.
2694 * Let g be a generator of Zp; that is, gcd(g, p - 1) = 1 and g^q = 1
2695 * mod p. We expect M to be in the 500-bit range and n relatively small,
2696 * like 25, so the likelihood of a randomly generated element of x mod q
2697 * of Zq colliding with a factor of p - 1 is very small and can be
2698 * avoided. Associated with each s'[j] is an element s[j] such that s[j]
2699 * s'[j] = s'[j] mod q. We find s[j] as the quotient (q + s'[j]) /
2700 * s'[j]. These are the parameters of the scheme and they are expensive
2703 * We set up an instance of the scheme as follows. A set of random
2704 * values x[j] mod q (j = 1...n), are generated as the zeros of a
2705 * polynomial of order n. The product terms (x - x[j]) are expanded to
2706 * form coefficients a[i] mod q (i = 0...n) in powers of x. These are
2707 * used as exponents of the generator g mod p to generate the private
2708 * encryption key A. The pair (gbar, ghat) of public server keys and the
2709 * pairs (xbar[j], xhat[j]) (j = 1...n) of private client keys are used
2710 * to construct the decryption keys. The devil is in the details.
2712 * The distinguishing characteristic of this scheme is the capability to
2713 * revoke keys. Included in the calculation of E, gbar and ghat is the
2714 * product s = prod(s'[j]) (j = 1...n) above. If the factor s'[j] is
2715 * subsequently removed from the product and E, gbar and ghat
2716 * recomputed, the jth client will no longer be able to compute E^-1 and
2717 * thus unable to decrypt the block.
2721 * The scheme goes like this. Bob has the server values (p, A, q, gbar,
2722 * ghat) and Alice the client values (p, xbar, xhat).
2724 * Alice rolls new random challenge r (0 < r < p) and sends to Bob in
2725 * the MV request message. Bob rolls new random k (0 < k < q), encrypts
2726 * y = A^k mod p (a permutation) and sends (hash(y), gbar^k, ghat^k) to
2729 * Alice receives the response and computes the decryption key (the
2730 * inverse permutation) from previously obtained (xbar, xhat) and
2731 * (gbar^k, ghat^k) in the message. She computes the inverse, which is
2732 * unique by reasons explained in the ntp-keygen.c program sources. If
2733 * the hash of this result matches hash(y), Alice knows that Bob has the
2734 * group key b. The signed response binds this knowledge to Bob's
2735 * private key and the public key previously received in his
2738 * crypto_alice3 - construct Alice's challenge in MV scheme
2742 * XEVNT_PUB bad or missing public key
2743 * XEVNT_ID bad or missing group key
2744 * XEVNT_PER host certificate expired
2748 struct peer *peer, /* peer pointer */
2749 struct value *vp /* value pointer */
2752 DSA *dsa; /* MV parameters */
2753 BN_CTX *bctx; /* BIGNUM context */
2754 EVP_MD_CTX ctx; /* signature context */
2759 * The identity parameters must have correct format and content.
2761 if (peer->ident_pkey == NULL)
2764 if ((dsa = peer->ident_pkey->pkey.dsa) == NULL) {
2765 msyslog(LOG_INFO, "crypto_alice3: defective key");
2770 * Roll new random r (0 < r < q). The OpenSSL library has a bug
2771 * omitting BN_rand_range, so we have to do it the hard way.
2773 bctx = BN_CTX_new();
2774 len = BN_num_bytes(dsa->p);
2775 if (peer->iffval != NULL)
2776 BN_free(peer->iffval);
2777 peer->iffval = BN_new();
2778 BN_rand(peer->iffval, len * 8, -1, 1); /* r */
2779 BN_mod(peer->iffval, peer->iffval, dsa->p, bctx);
2783 * Sign and send to Bob. The filestamp is from the local file.
2785 tstamp = crypto_time();
2786 memset(vp, 0, sizeof(struct value));
2787 vp->tstamp = htonl(tstamp);
2788 vp->fstamp = htonl(peer->fstamp);
2789 vp->vallen = htonl(len);
2790 vp->ptr = emalloc(len);
2791 BN_bn2bin(peer->iffval, vp->ptr);
2796 if (tstamp < cinfo->first || tstamp > cinfo->last)
2799 vp->sig = emalloc(sign_siglen);
2800 EVP_SignInit(&ctx, sign_digest);
2801 EVP_SignUpdate(&ctx, (u_char *)&vp->tstamp, 12);
2802 EVP_SignUpdate(&ctx, vp->ptr, len);
2803 if (EVP_SignFinal(&ctx, vp->sig, &len, sign_pkey))
2804 vp->siglen = htonl(len);
2810 * crypto_bob3 - construct Bob's response to Alice's challenge
2814 * XEVNT_ERR protocol error
2815 * XEVNT_PER host certificate expired
2819 struct exten *ep, /* extension pointer */
2820 struct value *vp /* value pointer */
2823 DSA *dsa; /* MV parameters */
2824 DSA *sdsa; /* DSA signature context fake */
2825 BN_CTX *bctx; /* BIGNUM context */
2826 EVP_MD_CTX ctx; /* signature context */
2827 tstamp_t tstamp; /* NTP timestamp */
2833 * If the MV parameters are not valid, something awful
2834 * happened or we are being tormented.
2836 if (mvpar_pkey == NULL) {
2837 msyslog(LOG_INFO, "crypto_bob3: scheme unavailable");
2840 dsa = mvpar_pkey->pkey.dsa;
2843 * Extract r from the challenge.
2845 len = ntohl(ep->vallen);
2846 if ((r = BN_bin2bn((u_char *)ep->pkt, len, NULL)) == NULL) {
2847 msyslog(LOG_ERR, "crypto_bob3 %s\n",
2848 ERR_error_string(ERR_get_error(), NULL));
2853 * Bob rolls random k (0 < k < q), making sure it is not a
2854 * factor of q. He then computes y = A^k r and sends (hash(y),
2855 * gbar^k, ghat^k) to Alice.
2857 bctx = BN_CTX_new(); k = BN_new(); u = BN_new();
2859 sdsa->p = BN_new(); sdsa->q = BN_new(); sdsa->g = BN_new();
2861 BN_rand(k, BN_num_bits(dsa->q), 0, 0);
2862 BN_mod(k, k, dsa->q, bctx);
2863 BN_gcd(u, k, dsa->q, bctx);
2867 BN_mod_exp(u, dsa->g, k, dsa->p, bctx); /* A r */
2868 BN_mod_mul(u, u, r, dsa->p, bctx);
2869 bighash(u, sdsa->p);
2870 BN_mod_exp(sdsa->q, dsa->priv_key, k, dsa->p, bctx); /* gbar */
2871 BN_mod_exp(sdsa->g, dsa->pub_key, k, dsa->p, bctx); /* ghat */
2872 BN_CTX_free(bctx); BN_free(k); BN_free(r); BN_free(u);
2875 * Encode the values in ASN.1 and sign.
2877 tstamp = crypto_time();
2878 memset(vp, 0, sizeof(struct value));
2879 vp->tstamp = htonl(tstamp);
2880 vp->fstamp = htonl(mv_fstamp);
2881 len = i2d_DSAparams(sdsa, NULL);
2883 msyslog(LOG_ERR, "crypto_bob3 %s\n",
2884 ERR_error_string(ERR_get_error(), NULL));
2888 vp->vallen = htonl(len);
2891 i2d_DSAparams(sdsa, &ptr);
2897 if (tstamp < cinfo->first || tstamp > cinfo->last)
2900 vp->sig = emalloc(sign_siglen);
2901 EVP_SignInit(&ctx, sign_digest);
2902 EVP_SignUpdate(&ctx, (u_char *)&vp->tstamp, 12);
2903 EVP_SignUpdate(&ctx, vp->ptr, len);
2904 if (EVP_SignFinal(&ctx, vp->sig, &len, sign_pkey))
2905 vp->siglen = htonl(len);
2911 * crypto_mv - verify Bob's response to Alice's challenge
2915 * XEVNT_PUB bad or missing public key
2916 * XEVNT_ID bad or missing group key
2917 * XEVNT_ERR protocol error
2918 * XEVNT_FSP bad filestamp
2922 struct exten *ep, /* extension pointer */
2923 struct peer *peer /* peer structure pointer */
2926 DSA *dsa; /* MV parameters */
2927 DSA *sdsa; /* DSA parameters */
2928 BN_CTX *bctx; /* BIGNUM context */
2935 * If the MV parameters are not valid or no challenge was sent,
2936 * something awful happened or we are being tormented.
2938 if (peer->ident_pkey == NULL) {
2939 msyslog(LOG_INFO, "crypto_mv: scheme unavailable");
2942 if (ntohl(ep->fstamp) != peer->fstamp) {
2943 msyslog(LOG_INFO, "crypto_mv: invalid filestamp %u",
2947 if ((dsa = peer->ident_pkey->pkey.dsa) == NULL) {
2948 msyslog(LOG_INFO, "crypto_mv: defective key");
2951 if (peer->iffval == NULL) {
2952 msyslog(LOG_INFO, "crypto_mv: missing challenge");
2957 * Extract the (hash(y), gbar, ghat) values from the response.
2959 bctx = BN_CTX_new(); k = BN_new(); u = BN_new(); v = BN_new();
2960 len = ntohl(ep->vallen);
2961 ptr = (const u_char *)ep->pkt;
2962 if ((sdsa = d2i_DSAparams(NULL, &ptr, len)) == NULL) {
2963 msyslog(LOG_ERR, "crypto_mv %s\n",
2964 ERR_error_string(ERR_get_error(), NULL));
2969 * Compute (gbar^xhat ghat^xbar)^-1 mod p.
2971 BN_mod_exp(u, sdsa->q, dsa->pub_key, dsa->p, bctx);
2972 BN_mod_exp(v, sdsa->g, dsa->priv_key, dsa->p, bctx);
2973 BN_mod_mul(u, u, v, dsa->p, bctx);
2974 BN_mod_inverse(u, u, dsa->p, bctx);
2975 BN_mod_mul(v, u, peer->iffval, dsa->p, bctx);
2978 * The result should match the hash of r mod p.
2981 temp = BN_cmp(v, sdsa->p);
2982 BN_CTX_free(bctx); BN_free(k); BN_free(u); BN_free(v);
2983 BN_free(peer->iffval);
2984 peer->iffval = NULL;
2995 ***********************************************************************
2997 * The following routines are used to manipulate certificates *
2999 ***********************************************************************
3002 * cert_parse - parse x509 certificate and create info/value structures.
3004 * The server certificate includes the version number, issuer name,
3005 * subject name, public key and valid date interval. If the issuer name
3006 * is the same as the subject name, the certificate is self signed and
3007 * valid only if the server is configured as trustable. If the names are
3008 * different, another issuer has signed the server certificate and
3009 * vouched for it. In this case the server certificate is valid if
3010 * verified by the issuer public key.
3012 * Returns certificate info/value pointer if valid, NULL if not.
3014 struct cert_info * /* certificate information structure */
3016 u_char *asn1cert, /* X509 certificate */
3017 u_int len, /* certificate length */
3018 tstamp_t fstamp /* filestamp */
3021 X509 *cert; /* X509 certificate */
3022 X509_EXTENSION *ext; /* X509v3 extension */
3023 struct cert_info *ret; /* certificate info/value */
3025 X509V3_EXT_METHOD *method;
3026 char pathbuf[MAXFILENAME];
3032 * Decode ASN.1 objects and construct certificate structure.
3035 if ((cert = d2i_X509(NULL, &uptr, len)) == NULL) {
3036 msyslog(LOG_ERR, "cert_parse %s\n",
3037 ERR_error_string(ERR_get_error(), NULL));
3042 * Extract version, subject name and public key.
3044 ret = emalloc(sizeof(struct cert_info));
3045 memset(ret, 0, sizeof(struct cert_info));
3046 if ((ret->pkey = X509_get_pubkey(cert)) == NULL) {
3047 msyslog(LOG_ERR, "cert_parse %s\n",
3048 ERR_error_string(ERR_get_error(), NULL));
3053 ret->version = X509_get_version(cert);
3054 X509_NAME_oneline(X509_get_subject_name(cert), pathbuf,
3056 ptr = strstr(pathbuf, "CN=");
3058 msyslog(LOG_INFO, "cert_parse: invalid subject %s",
3064 ret->subject = emalloc(strlen(ptr) + 1);
3065 strcpy(ret->subject, ptr + 3);
3068 * Extract remaining objects. Note that the NTP serial number is
3069 * the NTP seconds at the time of signing, but this might not be
3070 * the case for other authority. We don't bother to check the
3071 * objects at this time, since the real crunch can happen only
3072 * when the time is valid but not yet certificated.
3074 ret->nid = OBJ_obj2nid(cert->cert_info->signature->algorithm);
3075 ret->digest = (const EVP_MD *)EVP_get_digestbynid(ret->nid);
3077 (u_long)ASN1_INTEGER_get(X509_get_serialNumber(cert));
3078 X509_NAME_oneline(X509_get_issuer_name(cert), pathbuf,
3080 if ((ptr = strstr(pathbuf, "CN=")) == NULL) {
3081 msyslog(LOG_INFO, "cert_parse: invalid issuer %s",
3087 ret->issuer = emalloc(strlen(ptr) + 1);
3088 strcpy(ret->issuer, ptr + 3);
3089 ret->first = asn2ntp(X509_get_notBefore(cert));
3090 ret->last = asn2ntp(X509_get_notAfter(cert));
3093 * Extract extension fields. These are ad hoc ripoffs of
3094 * currently assigned functions and will certainly be changed
3095 * before prime time.
3097 cnt = X509_get_ext_count(cert);
3098 for (i = 0; i < cnt; i++) {
3099 ext = X509_get_ext(cert, i);
3100 method = X509V3_EXT_get(ext);
3101 temp = OBJ_obj2nid(ext->object);
3105 * If a key_usage field is present, we decode whether
3106 * this is a trusted or private certificate. This is
3107 * dorky; all we want is to compare NIDs, but OpenSSL
3108 * insists on BIO text strings.
3110 case NID_ext_key_usage:
3111 bp = BIO_new(BIO_s_mem());
3112 X509V3_EXT_print(bp, ext, 0, 0);
3113 BIO_gets(bp, pathbuf, MAXFILENAME);
3117 printf("cert_parse: %s: %s\n",
3118 OBJ_nid2ln(temp), pathbuf);
3120 if (strcmp(pathbuf, "Trust Root") == 0)
3121 ret->flags |= CERT_TRUST;
3122 else if (strcmp(pathbuf, "Private") == 0)
3123 ret->flags |= CERT_PRIV;
3127 * If a NID_subject_key_identifier field is present, it
3128 * contains the GQ public key.
3130 case NID_subject_key_identifier:
3131 ret->grplen = ext->value->length - 2;
3132 ret->grpkey = emalloc(ret->grplen);
3133 memcpy(ret->grpkey, &ext->value->data[2],
3140 * If certificate is self signed, verify signature.
3142 if (strcmp(ret->subject, ret->issuer) == 0) {
3143 if (!X509_verify(cert, ret->pkey)) {
3145 "cert_parse: signature not verified %s",
3154 * Verify certificate valid times. Note that certificates cannot
3157 if (ret->first > ret->last || ret->first < fstamp) {
3159 "cert_parse: invalid certificate %s first %u last %u fstamp %u",
3160 ret->subject, ret->first, ret->last, fstamp);
3167 * Build the value structure to sign and send later.
3169 ret->cert.fstamp = htonl(fstamp);
3170 ret->cert.vallen = htonl(len);
3171 ret->cert.ptr = emalloc(len);
3172 memcpy(ret->cert.ptr, asn1cert, len);
3175 X509_print_fp(stdout, cert);
3183 * cert_sign - sign x509 certificate equest and update value structure.
3185 * The certificate request includes a copy of the host certificate,
3186 * which includes the version number, subject name and public key of the
3187 * host. The resulting certificate includes these values plus the
3188 * serial number, issuer name and valid interval of the server. The
3189 * valid interval extends from the current time to the same time one
3190 * year hence. This may extend the life of the signed certificate beyond
3191 * that of the signer certificate.
3193 * It is convenient to use the NTP seconds of the current time as the
3194 * serial number. In the value structure the timestamp is the current
3195 * time and the filestamp is taken from the extension field. Note this
3196 * routine is called only when the client clock is synchronized to a
3197 * proventic source, so timestamp comparisons are valid.
3199 * The host certificate is valid from the time it was generated for a
3200 * period of one year. A signed certificate is valid from the time of
3201 * signature for a period of one year, but only the host certificate (or
3202 * sign certificate if used) is actually used to encrypt and decrypt
3203 * signatures. The signature trail is built from the client via the
3204 * intermediate servers to the trusted server. Each signature on the
3205 * trail must be valid at the time of signature, but it could happen
3206 * that a signer certificate expire before the signed certificate, which
3207 * remains valid until its expiration.
3211 * XEVNT_PUB bad or missing public key
3212 * XEVNT_CRT bad or missing certificate
3213 * XEVNT_VFY certificate not verified
3214 * XEVNT_PER host certificate expired
3218 struct exten *ep, /* extension field pointer */
3219 struct value *vp /* value pointer */
3222 X509 *req; /* X509 certificate request */
3223 X509 *cert; /* X509 certificate */
3224 X509_EXTENSION *ext; /* certificate extension */
3225 ASN1_INTEGER *serial; /* serial number */
3226 X509_NAME *subj; /* distinguished (common) name */
3227 EVP_PKEY *pkey; /* public key */
3228 EVP_MD_CTX ctx; /* message digest context */
3229 tstamp_t tstamp; /* NTP timestamp */
3235 * Decode ASN.1 objects and construct certificate structure.
3236 * Make sure the system clock is synchronized to a proventic
3239 tstamp = crypto_time();
3243 if (tstamp < cinfo->first || tstamp > cinfo->last)
3246 ptr = (u_char *)ep->pkt;
3247 if ((req = d2i_X509(NULL, &ptr, ntohl(ep->vallen))) == NULL) {
3248 msyslog(LOG_ERR, "cert_sign %s\n",
3249 ERR_error_string(ERR_get_error(), NULL));
3253 * Extract public key and check for errors.
3255 if ((pkey = X509_get_pubkey(req)) == NULL) {
3256 msyslog(LOG_ERR, "cert_sign %s\n",
3257 ERR_error_string(ERR_get_error(), NULL));
3263 * Generate X509 certificate signed by this server. For this
3264 * purpose the issuer name is the server name. Also copy any
3265 * extensions that might be present.
3268 X509_set_version(cert, X509_get_version(req));
3269 serial = ASN1_INTEGER_new();
3270 ASN1_INTEGER_set(serial, tstamp);
3271 X509_set_serialNumber(cert, serial);
3272 X509_gmtime_adj(X509_get_notBefore(cert), 0L);
3273 X509_gmtime_adj(X509_get_notAfter(cert), YEAR);
3274 subj = X509_get_issuer_name(cert);
3275 X509_NAME_add_entry_by_txt(subj, "commonName", MBSTRING_ASC,
3276 (u_char *)sys_hostname, strlen(sys_hostname), -1, 0);
3277 subj = X509_get_subject_name(req);
3278 X509_set_subject_name(cert, subj);
3279 X509_set_pubkey(cert, pkey);
3280 ext = X509_get_ext(req, 0);
3281 temp = X509_get_ext_count(req);
3282 for (i = 0; i < temp; i++) {
3283 ext = X509_get_ext(req, i);
3284 X509_add_ext(cert, ext, -1);
3289 * Sign and verify the certificate.
3291 X509_sign(cert, sign_pkey, sign_digest);
3292 if (!X509_verify(cert, sign_pkey)) {
3293 printf("cert_sign\n%s\n",
3294 ERR_error_string(ERR_get_error(), NULL));
3298 len = i2d_X509(cert, NULL);
3301 * Build and sign the value structure. We have to sign it here,
3302 * since the response has to be returned right away. This is a
3305 memset(vp, 0, sizeof(struct value));
3306 vp->tstamp = htonl(tstamp);
3307 vp->fstamp = ep->fstamp;
3308 vp->vallen = htonl(len);
3309 vp->ptr = emalloc(len);
3311 i2d_X509(cert, &ptr);
3313 vp->sig = emalloc(sign_siglen);
3314 EVP_SignInit(&ctx, sign_digest);
3315 EVP_SignUpdate(&ctx, (u_char *)vp, 12);
3316 EVP_SignUpdate(&ctx, vp->ptr, len);
3317 if (EVP_SignFinal(&ctx, vp->sig, &len, sign_pkey))
3318 vp->siglen = htonl(len);
3321 X509_print_fp(stdout, cert);
3329 * cert_valid - verify certificate with given public key
3331 * This is pretty ugly, as the certificate has to be verified in the
3332 * OpenSSL X509 structure, not in the DER format in the info/value
3337 * XEVNT_VFY certificate not verified
3341 struct cert_info *cinf, /* certificate information structure */
3342 EVP_PKEY *pkey /* public key */
3345 X509 *cert; /* X509 certificate */
3348 if (cinf->flags & CERT_SIGN)
3351 ptr = (u_char *)cinf->cert.ptr;
3352 cert = d2i_X509(NULL, &ptr, ntohl(cinf->cert.vallen));
3353 if (cert == NULL || !X509_verify(cert, pkey))
3362 * cert - install certificate in certificate list
3364 * This routine encodes an extension field into a certificate info/value
3365 * structure. It searches the certificate list for duplicates and
3366 * expunges whichever is older. It then searches the list for other
3367 * certificates that might be verified by this latest one. Finally, it
3368 * inserts this certificate first on the list.
3372 * XEVNT_FSP bad or missing filestamp
3373 * XEVNT_CRT bad or missing certificate
3377 struct exten *ep, /* cert info/value */
3378 struct peer *peer /* peer structure */
3381 struct cert_info *cp, *xp, *yp, **zp;
3384 * Parse and validate the signed certificate. If valid,
3385 * construct the info/value structure; otherwise, scamper home.
3387 if ((cp = cert_parse((u_char *)ep->pkt, ntohl(ep->vallen),
3388 ntohl(ep->fstamp))) == NULL)
3392 * Scan certificate list looking for another certificate with
3393 * the same subject and issuer. If another is found with the
3394 * same or older filestamp, unlink it and return the goodies to
3395 * the heap. If another is found with a later filestamp, discard
3396 * the new one and leave the building.
3398 * Make a note to study this issue again. An earlier certificate
3399 * with a long lifetime might be overtaken by a later
3400 * certificate with a short lifetime, thus invalidating the
3401 * earlier signature. However, we gotta find a way to leak old
3402 * stuff from the cache, so we do it anyway.
3406 for (xp = cinfo; xp != NULL; xp = xp->link) {
3407 if (strcmp(cp->subject, xp->subject) == 0 &&
3408 strcmp(cp->issuer, xp->issuer) == 0) {
3409 if (ntohl(cp->cert.fstamp) <=
3410 ntohl(xp->cert.fstamp)) {
3425 * Scan the certificate list to see if Y is signed by X. This is
3426 * independent of order.
3428 for (yp = cinfo; yp != NULL; yp = yp->link) {
3429 for (xp = cinfo; xp != NULL; xp = xp->link) {
3432 * If the issuer of certificate Y matches the
3433 * subject of certificate X, verify the
3434 * signature of Y using the public key of X. If
3437 if (strcmp(yp->issuer, xp->subject) != 0 ||
3438 xp->flags & CERT_ERROR)
3441 if (cert_valid(yp, xp->pkey) != XEVNT_OK) {
3442 yp->flags |= CERT_ERROR;
3447 * The signature Y is valid only if it begins
3448 * during the lifetime of X; however, it is not
3449 * necessarily an error, since some other
3450 * certificate might sign Y.
3452 if (yp->first < xp->first || yp->first >
3456 yp->flags |= CERT_SIGN;
3459 * If X is trusted, then Y is trusted. Note that
3460 * we might stumble over a self-signed
3461 * certificate that is not trusted, at least
3462 * temporarily. This can happen when a dude
3463 * first comes up, but has not synchronized the
3464 * clock and had its certificate signed by its
3465 * server. In case of broken certificate trail,
3466 * this might result in a loop that could
3467 * persist until timeout.
3469 if (!(xp->flags & (CERT_TRUST | CERT_VALID)))
3472 yp->flags |= CERT_VALID;
3475 * If subject Y matches the server subject name,
3476 * then Y has completed the certificate trail.
3477 * Save the group key and light the valid bit.
3479 if (strcmp(yp->subject, peer->subject) != 0)
3482 if (yp->grpkey != NULL) {
3483 if (peer->grpkey != NULL)
3484 BN_free(peer->grpkey);
3485 peer->grpkey = BN_bin2bn(yp->grpkey,
3488 peer->crypto |= CRYPTO_FLAG_VALID;
3491 * If the server has an an identity scheme,
3492 * fetch the identity credentials. If not, the
3493 * identity is verified only by the trusted
3494 * certificate. The next signature will set the
3497 if (peer->crypto & (CRYPTO_FLAG_GQ |
3498 CRYPTO_FLAG_IFF | CRYPTO_FLAG_MV))
3501 peer->crypto |= CRYPTO_FLAG_VRFY;
3506 * That was awesome. Now update the timestamps and signatures.
3514 * cert_free - free certificate information structure
3518 struct cert_info *cinf /* certificate info/value structure */
3521 if (cinf->pkey != NULL)
3522 EVP_PKEY_free(cinf->pkey);
3523 if (cinf->subject != NULL)
3524 free(cinf->subject);
3525 if (cinf->issuer != NULL)
3527 if (cinf->grpkey != NULL)
3529 value_free(&cinf->cert);
3535 ***********************************************************************
3537 * The following routines are used only at initialization time *
3539 ***********************************************************************
3542 * crypto_key - load cryptographic parameters and keys from files
3544 * This routine loads a PEM-encoded public/private key pair and extracts
3545 * the filestamp from the file name.
3547 * Returns public key pointer if valid, NULL if not. Side effect updates
3548 * the filestamp if valid.
3552 char *cp, /* file name */
3553 tstamp_t *fstamp /* filestamp */
3556 FILE *str; /* file handle */
3557 EVP_PKEY *pkey = NULL; /* public/private key */
3558 char filename[MAXFILENAME]; /* name of key file */
3559 char linkname[MAXFILENAME]; /* filestamp buffer) */
3560 char statstr[NTP_MAXSTRLEN]; /* statistics for filegen */
3564 * Open the key file. If the first character of the file name is
3565 * not '/', prepend the keys directory string. If something goes
3566 * wrong, abandon ship.
3569 strcpy(filename, cp);
3571 snprintf(filename, MAXFILENAME, "%s/%s", keysdir, cp);
3572 str = fopen(filename, "r");
3577 * Read the filestamp, which is contained in the first line.
3579 if ((ptr = fgets(linkname, MAXFILENAME, str)) == NULL) {
3580 msyslog(LOG_ERR, "crypto_key: no data %s\n",
3585 if ((ptr = strrchr(ptr, '.')) == NULL) {
3586 msyslog(LOG_ERR, "crypto_key: no filestamp %s\n",
3591 if (sscanf(++ptr, "%u", fstamp) != 1) {
3592 msyslog(LOG_ERR, "crypto_key: invalid timestamp %s\n",
3599 * Read and decrypt PEM-encoded private key.
3601 pkey = PEM_read_PrivateKey(str, NULL, NULL, passwd);
3604 msyslog(LOG_ERR, "crypto_key %s\n",
3605 ERR_error_string(ERR_get_error(), NULL));
3610 * Leave tracks in the cryptostats.
3612 if ((ptr = strrchr(linkname, '\n')) != NULL)
3614 snprintf(statstr, NTP_MAXSTRLEN, "%s mod %d", &linkname[2],
3615 EVP_PKEY_size(pkey) * 8);
3616 record_crypto_stats(NULL, statstr);
3619 printf("crypto_key: %s\n", statstr);
3621 if (pkey->type == EVP_PKEY_DSA)
3622 DSA_print_fp(stdout, pkey->pkey.dsa, 0);
3624 RSA_print_fp(stdout, pkey->pkey.rsa, 0);
3632 * crypto_cert - load certificate from file
3634 * This routine loads a X.509 RSA or DSA certificate from a file and
3635 * constructs a info/cert value structure for this machine. The
3636 * structure includes a filestamp extracted from the file name. Later
3637 * the certificate can be sent to another machine by request.
3639 * Returns certificate info/value pointer if valid, NULL if not.
3641 static struct cert_info * /* certificate information */
3643 char *cp /* file name */
3646 struct cert_info *ret; /* certificate information */
3647 FILE *str; /* file handle */
3648 char filename[MAXFILENAME]; /* name of certificate file */
3649 char linkname[MAXFILENAME]; /* filestamp buffer */
3650 char statstr[NTP_MAXSTRLEN]; /* statistics for filegen */
3651 tstamp_t fstamp; /* filestamp */
3654 char *name, *header;
3658 * Open the certificate file. If the first character of the file
3659 * name is not '/', prepend the keys directory string. If
3660 * something goes wrong, abandon ship.
3663 strcpy(filename, cp);
3665 snprintf(filename, MAXFILENAME, "%s/%s", keysdir, cp);
3666 str = fopen(filename, "r");
3671 * Read the filestamp, which is contained in the first line.
3673 if ((ptr = fgets(linkname, MAXFILENAME, str)) == NULL) {
3674 msyslog(LOG_ERR, "crypto_cert: no data %s\n",
3679 if ((ptr = strrchr(ptr, '.')) == NULL) {
3680 msyslog(LOG_ERR, "crypto_cert: no filestamp %s\n",
3685 if (sscanf(++ptr, "%u", &fstamp) != 1) {
3686 msyslog(LOG_ERR, "crypto_cert: invalid filestamp %s\n",
3693 * Read PEM-encoded certificate and install.
3695 if (!PEM_read(str, &name, &header, &data, &len)) {
3696 msyslog(LOG_ERR, "crypto_cert %s\n",
3697 ERR_error_string(ERR_get_error(), NULL));
3702 if (strcmp(name, "CERTIFICATE") !=0) {
3703 msyslog(LOG_INFO, "crypto_cert: wrong PEM type %s",
3713 * Parse certificate and generate info/value structure.
3715 ret = cert_parse(data, len, fstamp);
3721 if ((ptr = strrchr(linkname, '\n')) != NULL)
3723 snprintf(statstr, NTP_MAXSTRLEN,
3724 "%s 0x%x len %lu", &linkname[2], ret->flags, len);
3725 record_crypto_stats(NULL, statstr);
3728 printf("crypto_cert: %s\n", statstr);
3735 * crypto_tai - load leapseconds table from file
3737 * This routine loads the ERTS leapsecond file in NIST text format,
3738 * converts to a value structure and extracts a filestamp from the file
3739 * name. The data are used to establish the TAI offset from UTC, which
3740 * is provided to the kernel if supported. Later the data can be sent to
3741 * another machine on request.
3745 char *cp /* file name */
3748 FILE *str; /* file handle */
3749 char buf[NTP_MAXSTRLEN]; /* file line buffer */
3750 u_int32 leapsec[MAX_LEAP]; /* NTP time at leaps */
3751 int offset; /* offset at leap (s) */
3752 char filename[MAXFILENAME]; /* name of leapseconds file */
3753 char linkname[MAXFILENAME]; /* file link (for filestamp) */
3754 char statstr[NTP_MAXSTRLEN]; /* statistics for filegen */
3755 tstamp_t fstamp; /* filestamp */
3762 * Open the file and discard comment lines. If the first
3763 * character of the file name is not '/', prepend the keys
3764 * directory string. If the file is not found, not to worry; it
3765 * can be retrieved over the net. But, if it is found with
3766 * errors, we crash and burn.
3769 strcpy(filename, cp);
3771 snprintf(filename, MAXFILENAME, "%s/%s", keysdir, cp);
3772 if ((str = fopen(filename, "r")) == NULL)
3776 * Extract filestamp if present.
3778 rval = readlink(filename, linkname, MAXFILENAME - 1);
3780 linkname[rval] = '\0';
3781 dp = strrchr(linkname, '.');
3783 dp = strrchr(filename, '.');
3786 sscanf(++dp, "%u", &fstamp);
3789 tai_leap.fstamp = htonl(fstamp);
3792 * We are rather paranoid here, since an intruder might cause a
3793 * coredump by infiltrating naughty values. Empty lines and
3794 * comments are ignored. Other lines must begin with two
3795 * integers followed by junk or comments. The first integer is
3796 * the NTP seconds of leap insertion, the second is the offset
3797 * of TAI relative to UTC after that insertion. The second word
3798 * must equal the initial insertion of ten seconds on 1 January
3799 * 1972 plus one second for each succeeding insertion.
3802 while (i < MAX_LEAP) {
3803 dp = fgets(buf, NTP_MAXSTRLEN - 1, str);
3807 if (strlen(buf) < 1)
3813 if (sscanf(buf, "%u %d", &leapsec[i], &offset) != 2)
3816 if (i != offset - TAI_1972)
3824 "crypto_tai: leapseconds file %s error %d", cp,
3830 * The extension field table entries consists of the NTP seconds
3831 * of leap insertion in network byte order.
3833 len = i * sizeof(u_int32);
3834 tai_leap.vallen = htonl(len);
3836 tai_leap.ptr = (u_char *)ptr;
3837 for (j = 0; j < i; j++)
3838 *ptr++ = htonl(leapsec[j]);
3839 crypto_flags |= CRYPTO_FLAG_TAI;
3840 snprintf(statstr, NTP_MAXSTRLEN, "%s fs %u leap %u len %u", cp, fstamp,
3842 record_crypto_stats(NULL, statstr);
3845 printf("crypto_tai: %s\n", statstr);
3851 * crypto_setup - load keys, certificate and leapseconds table
3853 * This routine loads the public/private host key and certificate. If
3854 * available, it loads the public/private sign key, which defaults to
3855 * the host key, and leapseconds table. The host key must be RSA, but
3856 * the sign key can be either RSA or DSA. In either case, the public key
3857 * on the certificate must agree with the sign key.
3862 EVP_PKEY *pkey; /* private/public key pair */
3863 char filename[MAXFILENAME]; /* file name buffer */
3864 l_fp seed; /* crypto PRNG seed as NTP timestamp */
3865 tstamp_t fstamp; /* filestamp */
3866 tstamp_t sstamp; /* sign filestamp */
3871 * Initialize structures.
3876 gethostname(filename, MAXFILENAME);
3877 bytes = strlen(filename) + 1;
3878 sys_hostname = emalloc(bytes);
3879 memcpy(sys_hostname, filename, bytes);
3881 passwd = sys_hostname;
3882 memset(&hostval, 0, sizeof(hostval));
3883 memset(&pubkey, 0, sizeof(pubkey));
3884 memset(&tai_leap, 0, sizeof(tai_leap));
3887 * Load required random seed file and seed the random number
3888 * generator. Be default, it is found in the user home
3889 * directory. The root home directory may be / or /root,
3890 * depending on the system. Wiggle the contents a bit and write
3891 * it back so the sequence does not repeat when we next restart.
3893 ERR_load_crypto_strings();
3894 if (rand_file == NULL) {
3895 if ((RAND_file_name(filename, MAXFILENAME)) != NULL) {
3896 rand_file = emalloc(strlen(filename) + 1);
3897 strcpy(rand_file, filename);
3899 } else if (*rand_file != '/') {
3900 snprintf(filename, MAXFILENAME, "%s/%s", keysdir,
3903 rand_file = emalloc(strlen(filename) + 1);
3904 strcpy(rand_file, filename);
3906 if (rand_file == NULL) {
3908 "crypto_setup: random seed file not specified");
3911 if ((bytes = RAND_load_file(rand_file, -1)) == 0) {
3913 "crypto_setup: random seed file %s not found\n",
3918 RAND_seed(&seed, sizeof(l_fp));
3919 RAND_write_file(rand_file);
3920 OpenSSL_add_all_algorithms();
3924 "crypto_setup: OpenSSL version %lx random seed file %s bytes read %d\n",
3925 SSLeay(), rand_file, bytes);
3929 * Load required host key from file "ntpkey_host_<hostname>". It
3930 * also becomes the default sign key.
3932 if (host_file == NULL) {
3933 snprintf(filename, MAXFILENAME, "ntpkey_host_%s",
3935 host_file = emalloc(strlen(filename) + 1);
3936 strcpy(host_file, filename);
3938 pkey = crypto_key(host_file, &fstamp);
3941 "crypto_setup: host key file %s not found or corrupt",
3948 hostval.fstamp = htonl(fstamp);
3949 if (host_pkey->type != EVP_PKEY_RSA) {
3951 "crypto_setup: host key is not RSA key type");
3954 hostval.vallen = htonl(strlen(sys_hostname));
3955 hostval.ptr = (u_char *)sys_hostname;
3958 * Construct public key extension field for agreement scheme.
3960 len = i2d_PublicKey(host_pkey, NULL);
3963 i2d_PublicKey(host_pkey, &ptr);
3964 pubkey.vallen = htonl(len);
3965 pubkey.fstamp = hostval.fstamp;
3968 * Load optional sign key from file "ntpkey_sign_<hostname>". If
3969 * loaded, it becomes the sign key.
3971 if (sign_file == NULL) {
3972 snprintf(filename, MAXFILENAME, "ntpkey_sign_%s",
3974 sign_file = emalloc(strlen(filename) + 1);
3975 strcpy(sign_file, filename);
3977 pkey = crypto_key(sign_file, &fstamp);
3982 sign_siglen = EVP_PKEY_size(sign_pkey);
3985 * Load optional IFF parameters from file
3986 * "ntpkey_iff_<hostname>".
3988 if (iffpar_file == NULL) {
3989 snprintf(filename, MAXFILENAME, "ntpkey_iff_%s",
3991 iffpar_file = emalloc(strlen(filename) + 1);
3992 strcpy(iffpar_file, filename);
3994 iffpar_pkey = crypto_key(iffpar_file, &if_fstamp);
3995 if (iffpar_pkey != NULL)
3996 crypto_flags |= CRYPTO_FLAG_IFF;
3999 * Load optional GQ parameters from file "ntpkey_gq_<hostname>".
4001 if (gqpar_file == NULL) {
4002 snprintf(filename, MAXFILENAME, "ntpkey_gq_%s",
4004 gqpar_file = emalloc(strlen(filename) + 1);
4005 strcpy(gqpar_file, filename);
4007 gqpar_pkey = crypto_key(gqpar_file, &gq_fstamp);
4008 if (gqpar_pkey != NULL)
4009 crypto_flags |= CRYPTO_FLAG_GQ;
4012 * Load optional MV parameters from file "ntpkey_mv_<hostname>".
4014 if (mvpar_file == NULL) {
4015 snprintf(filename, MAXFILENAME, "ntpkey_mv_%s",
4017 mvpar_file = emalloc(strlen(filename) + 1);
4018 strcpy(mvpar_file, filename);
4020 mvpar_pkey = crypto_key(mvpar_file, &mv_fstamp);
4021 if (mvpar_pkey != NULL)
4022 crypto_flags |= CRYPTO_FLAG_MV;
4025 * Load required certificate from file "ntpkey_cert_<hostname>".
4027 if (cert_file == NULL) {
4028 snprintf(filename, MAXFILENAME, "ntpkey_cert_%s",
4030 cert_file = emalloc(strlen(filename) + 1);
4031 strcpy(cert_file, filename);
4033 if ((cinfo = crypto_cert(cert_file)) == NULL) {
4035 "certificate file %s not found or corrupt",
4041 * The subject name must be the same as the host name, unless
4042 * the certificate is private, in which case it may have come
4043 * from another host.
4045 if (!(cinfo->flags & CERT_PRIV) && strcmp(cinfo->subject,
4046 sys_hostname) != 0) {
4048 "crypto_setup: certificate %s not for this host",
4055 * It the certificate is trusted, the subject must be the same
4056 * as the issuer, in other words it must be self signed.
4058 if (cinfo->flags & CERT_TRUST && strcmp(cinfo->subject,
4059 cinfo->issuer) != 0) {
4060 if (cert_valid(cinfo, sign_pkey) != XEVNT_OK) {
4062 "crypto_setup: certificate %s is trusted, but not self signed.",
4068 sign_digest = cinfo->digest;
4069 if (cinfo->flags & CERT_PRIV)
4070 crypto_flags |= CRYPTO_FLAG_PRIV;
4071 crypto_flags |= cinfo->nid << 16;
4074 * Load optional leapseconds table from file "ntpkey_leap". If
4075 * the file is missing or defective, the values can later be
4076 * retrieved from a server.
4078 if (leap_file == NULL)
4079 leap_file = "ntpkey_leap";
4080 crypto_tai(leap_file);
4084 "crypto_setup: flags 0x%x host %s signature %s\n",
4085 crypto_flags, sys_hostname, OBJ_nid2ln(cinfo->nid));
4091 * crypto_config - configure data from crypto configuration command.
4095 int item, /* configuration item */
4096 char *cp /* file name */
4102 * Set random seed file name.
4104 case CRYPTO_CONF_RAND:
4105 rand_file = emalloc(strlen(cp) + 1);
4106 strcpy(rand_file, cp);
4110 * Set private key password.
4112 case CRYPTO_CONF_PW:
4113 passwd = emalloc(strlen(cp) + 1);
4118 * Set host file name.
4120 case CRYPTO_CONF_PRIV:
4121 host_file = emalloc(strlen(cp) + 1);
4122 strcpy(host_file, cp);
4126 * Set sign key file name.
4128 case CRYPTO_CONF_SIGN:
4129 sign_file = emalloc(strlen(cp) + 1);
4130 strcpy(sign_file, cp);
4134 * Set iff parameters file name.
4136 case CRYPTO_CONF_IFFPAR:
4137 iffpar_file = emalloc(strlen(cp) + 1);
4138 strcpy(iffpar_file, cp);
4142 * Set gq parameters file name.
4144 case CRYPTO_CONF_GQPAR:
4145 gqpar_file = emalloc(strlen(cp) + 1);
4146 strcpy(gqpar_file, cp);
4150 * Set mv parameters file name.
4152 case CRYPTO_CONF_MVPAR:
4153 mvpar_file = emalloc(strlen(cp) + 1);
4154 strcpy(mvpar_file, cp);
4158 * Set identity scheme.
4160 case CRYPTO_CONF_IDENT:
4161 if (!strcasecmp(cp, "iff"))
4162 ident_scheme |= CRYPTO_FLAG_IFF;
4163 else if (!strcasecmp(cp, "gq"))
4164 ident_scheme |= CRYPTO_FLAG_GQ;
4165 else if (!strcasecmp(cp, "mv"))
4166 ident_scheme |= CRYPTO_FLAG_MV;
4170 * Set certificate file name.
4172 case CRYPTO_CONF_CERT:
4173 cert_file = emalloc(strlen(cp) + 1);
4174 strcpy(cert_file, cp);
4178 * Set leapseconds file name.
4180 case CRYPTO_CONF_LEAP:
4181 leap_file = emalloc(strlen(cp) + 1);
4182 strcpy(leap_file, cp);
4185 crypto_flags |= CRYPTO_FLAG_ENAB;
4188 int ntp_crypto_bs_pubkey;
4189 # endif /* OPENSSL */