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 u_int32 *cookiebuf = malloc(
868 RSA_size(host_pkey->pkey.rsa));
869 if (cookiebuf == NULL) {
873 if (RSA_private_decrypt(vallen,
877 RSA_PKCS1_OAEP_PADDING) != 4) {
882 cookie = ntohl(*cookiebuf);
891 * Install cookie values and light the cookie
892 * bit. If this is not broadcast client mode, we
896 peer->cookval.tstamp = ep->tstamp;
897 peer->cookval.fstamp = ep->fstamp;
898 if (peer->crypto & CRYPTO_FLAG_AGREE)
899 peer->pcookie ^= cookie;
901 peer->pcookie = cookie;
902 if (peer->hmode == MODE_CLIENT &&
903 !(peer->cast_flags & MDF_BCLNT))
904 peer->crypto |= CRYPTO_FLAG_AUTO;
906 peer->crypto &= ~CRYPTO_FLAG_AUTO;
907 peer->crypto |= CRYPTO_FLAG_AGREE;
908 peer->flash &= ~TEST8;
909 snprintf(statstr, NTP_MAXSTRLEN, "cook %x ts %u fs %u",
910 peer->pcookie, ntohl(ep->tstamp),
912 record_crypto_stats(&peer->srcadr, statstr);
915 printf("crypto_recv: %s\n", statstr);
920 * Install autokey values in broadcast client and
921 * symmetric modes. We have to do this every time the
922 * sever/peer cookie changes or a new keylist is
923 * rolled. Ordinarily, this is automatic as this message
924 * is piggybacked on the first NTP packet sent upon
925 * either of these events. Note that a broadcast client
926 * or symmetric peer can receive this response without a
929 case CRYPTO_AUTO | CRYPTO_RESP:
932 * Discard the message if invalid or identity
933 * not confirmed or signature not verified with
934 * respect to the receive autokey values.
936 if (!(peer->crypto & CRYPTO_FLAG_VRFY)) {
940 if ((rval = crypto_verify(ep, &peer->recval,
945 * Install autokey values and light the
946 * autokey bit. This is not hard.
948 if (peer->recval.ptr == NULL)
950 emalloc(sizeof(struct autokey));
951 bp = (struct autokey *)peer->recval.ptr;
952 peer->recval.tstamp = ep->tstamp;
953 peer->recval.fstamp = ep->fstamp;
954 ap = (struct autokey *)ep->pkt;
955 bp->seq = ntohl(ap->seq);
956 bp->key = ntohl(ap->key);
957 peer->pkeyid = bp->key;
958 peer->crypto |= CRYPTO_FLAG_AUTO;
959 peer->flash &= ~TEST8;
960 snprintf(statstr, NTP_MAXSTRLEN,
961 "auto seq %d key %x ts %u fs %u", bp->seq,
962 bp->key, ntohl(ep->tstamp),
964 record_crypto_stats(&peer->srcadr, statstr);
967 printf("crypto_recv: %s\n", statstr);
972 * X509 certificate sign response. Validate the
973 * certificate signed by the server and install. Later
974 * this can be provided to clients of this server in
975 * lieu of the self signed certificate in order to
976 * validate the public key.
978 case CRYPTO_SIGN | CRYPTO_RESP:
981 * Discard the message if invalid or not
984 if (!(peer->crypto & CRYPTO_FLAG_PROV)) {
988 if ((rval = crypto_verify(ep, NULL, peer)) !=
993 * Scan the certificate list to delete old
994 * versions and link the newest version first on
997 if ((rval = cert_install(ep, peer)) != XEVNT_OK)
1000 peer->crypto |= CRYPTO_FLAG_SIGN;
1001 peer->flash &= ~TEST8;
1002 temp32 = cinfo->nid;
1003 snprintf(statstr, NTP_MAXSTRLEN,
1004 "sign %s 0x%x %s (%u) fs %u",
1005 cinfo->issuer, cinfo->flags,
1006 OBJ_nid2ln(temp32), temp32,
1008 record_crypto_stats(&peer->srcadr, statstr);
1011 printf("crypto_recv: %s\n", statstr);
1016 * Install leapseconds table in symmetric modes. This
1017 * table is proventicated to the NIST primary servers,
1018 * either by copying the file containing the table from
1019 * a NIST server to a trusted server or directly using
1020 * this protocol. While the entire table is installed at
1021 * the server, presently only the current TAI offset is
1022 * provided via the kernel to other applications.
1027 * Discard the message if invalid.
1029 if ((rval = crypto_verify(ep, NULL, peer)) !=
1034 * Pass the extension field to the transmit
1035 * side. Continue below if a leapseconds table
1036 * accompanies the message.
1039 memcpy(fp, ep, len);
1040 temp32 = CRYPTO_RESP;
1041 fp->opcode |= htonl(temp32);
1043 if (len <= VALUE_LEN) {
1044 peer->flash &= ~TEST8;
1049 case CRYPTO_TAI | CRYPTO_RESP:
1052 * If this is a response, discard the message if
1053 * signature not verified with respect to the
1054 * leapsecond table values.
1056 if (peer->cmmd == NULL) {
1057 if ((rval = crypto_verify(ep,
1058 &peer->tai_leap, peer)) != XEVNT_OK)
1063 * Initialize peer variables with latest update.
1065 peer->tai_leap.tstamp = ep->tstamp;
1066 peer->tai_leap.fstamp = ep->fstamp;
1067 peer->tai_leap.vallen = ep->vallen;
1070 * Install the new table if there is no stored
1071 * table or the new table is more recent than
1072 * the stored table. Since a filestamp may have
1073 * changed, recompute the signatures.
1075 if (ntohl(peer->tai_leap.fstamp) >
1076 ntohl(tai_leap.fstamp)) {
1077 tai_leap.fstamp = ep->fstamp;
1078 tai_leap.vallen = ep->vallen;
1079 if (tai_leap.ptr != NULL)
1081 tai_leap.ptr = emalloc(vallen);
1082 memcpy(tai_leap.ptr, ep->pkt, vallen);
1085 crypto_flags |= CRYPTO_FLAG_TAI;
1086 peer->crypto |= CRYPTO_FLAG_LEAP;
1087 peer->flash &= ~TEST8;
1088 snprintf(statstr, NTP_MAXSTRLEN,
1089 "leap %u ts %u fs %u", vallen,
1090 ntohl(ep->tstamp), ntohl(ep->fstamp));
1091 record_crypto_stats(&peer->srcadr, statstr);
1094 printf("crypto_recv: %s\n", statstr);
1099 * We come here in symmetric modes for miscellaneous
1100 * commands that have value fields but are processed on
1101 * the transmit side. All we need do here is check for
1102 * valid field length. Remaining checks are below and on
1103 * the transmit side.
1110 if (len < VALUE_LEN) {
1117 * We come here for miscellaneous requests and unknown
1118 * requests and responses. If an unknown response or
1119 * error, forget it. If a request, save the extension
1120 * field for later. Unknown requests will be caught on
1121 * the transmit side.
1124 if (code & (CRYPTO_RESP | CRYPTO_ERROR)) {
1126 } else if ((rval = crypto_verify(ep, NULL,
1127 peer)) == XEVNT_OK) {
1129 memcpy(fp, ep, len);
1130 temp32 = CRYPTO_RESP;
1131 fp->opcode |= htonl(temp32);
1137 * We don't log length/format/timestamp errors and
1138 * duplicates, which are log clogging vulnerabilities.
1139 * The first error found terminates the extension field
1140 * scan and we return the laundry to the caller. A
1141 * length/format/timestamp error on transmit is
1142 * cheerfully ignored, as the message is not sent.
1144 if (rval > XEVNT_TSP) {
1145 snprintf(statstr, NTP_MAXSTRLEN,
1146 "error %x opcode %x ts %u fs %u", rval,
1147 code, tstamp, fstamp);
1148 record_crypto_stats(&peer->srcadr, statstr);
1149 report_event(rval, peer);
1152 printf("crypto_recv: %s\n", statstr);
1156 } else if (rval > XEVNT_OK && (code & CRYPTO_RESP)) {
1166 * crypto_xmit - construct extension fields
1168 * This routine is called both when an association is configured and
1169 * when one is not. The only case where this matters is to retrieve the
1170 * autokey information, in which case the caller has to provide the
1171 * association ID to match the association.
1173 * Returns length of extension field.
1177 struct pkt *xpkt, /* transmit packet pointer */
1178 struct sockaddr_storage *srcadr_sin, /* active runway */
1179 int start, /* offset to extension field */
1180 struct exten *ep, /* extension pointer */
1181 keyid_t cookie /* session cookie */
1184 u_int32 *pkt; /* packet pointer */
1185 struct peer *peer; /* peer structure pointer */
1186 u_int opcode; /* extension field opcode */
1187 struct exten *fp; /* extension pointers */
1188 struct cert_info *cp, *xp; /* certificate info/value pointer */
1189 char certname[MAXHOSTNAME + 1]; /* subject name buffer */
1190 char statstr[NTP_MAXSTRLEN]; /* statistics for filegen */
1200 * Generate the requested extension field request code, length
1201 * and association ID. If this is a response and the host is not
1202 * synchronized, light the error bit and go home.
1204 pkt = (u_int32 *)xpkt + start / 4;
1205 fp = (struct exten *)pkt;
1206 opcode = ntohl(ep->opcode);
1207 associd = (associd_t) ntohl(ep->associd);
1208 fp->associd = htonl(associd);
1211 tstamp = crypto_time();
1212 switch (opcode & 0xffff0000) {
1215 * Send association request and response with status word and
1216 * host name. Note, this message is not signed and the filestamp
1217 * contains only the status word.
1219 case CRYPTO_ASSOC | CRYPTO_RESP:
1220 len += crypto_send(fp, &hostval);
1221 fp->fstamp = htonl(crypto_flags);
1225 len += crypto_send(fp, &hostval);
1226 fp->fstamp = htonl(crypto_flags | ident_scheme);
1230 * Send certificate request. Use the values from the extension
1234 memset(&vtemp, 0, sizeof(vtemp));
1235 vtemp.tstamp = ep->tstamp;
1236 vtemp.fstamp = ep->fstamp;
1237 vtemp.vallen = ep->vallen;
1238 vtemp.ptr = (u_char *)ep->pkt;
1239 len += crypto_send(fp, &vtemp);
1243 * Send certificate response or sign request. Use the values
1244 * from the certificate cache. If the request contains no
1245 * subject name, assume the name of this host. This is for
1246 * backwards compatibility. Private certificates are never sent.
1249 case CRYPTO_CERT | CRYPTO_RESP:
1250 vallen = ntohl(ep->vallen);
1252 strcpy(certname, sys_hostname);
1253 } else if (vallen == 0 || vallen > MAXHOSTNAME) {
1258 memcpy(certname, ep->pkt, vallen);
1259 certname[vallen] = '\0';
1263 * Find all certificates with matching subject. If a
1264 * self-signed, trusted certificate is found, use that.
1265 * If not, use the first one with matching subject. A
1266 * private certificate is never divulged or signed.
1269 for (cp = cinfo; cp != NULL; cp = cp->link) {
1270 if (cp->flags & CERT_PRIV)
1273 if (strcmp(certname, cp->subject) == 0) {
1276 if (strcmp(certname, cp->issuer) ==
1277 0 && cp->flags & CERT_TRUST) {
1285 * Be careful who you trust. If not yet synchronized,
1286 * give back an empty response. If certificate not found
1287 * or beyond the lifetime, return an error. This is to
1288 * avoid a bad dude trying to get an expired certificate
1289 * re-signed. Otherwise, send it.
1291 * Note the timestamp and filestamp are taken from the
1292 * certificate value structure. For all certificates the
1293 * timestamp is the latest signature update time. For
1294 * host and imported certificates the filestamp is the
1295 * creation epoch. For signed certificates the filestamp
1296 * is the creation epoch of the trusted certificate at
1297 * the base of the certificate trail. In principle, this
1298 * allows strong checking for signature masquerade.
1305 else if (tstamp < xp->first || tstamp > xp->last)
1308 len += crypto_send(fp, &xp->cert);
1312 * Send challenge in Schnorr (IFF) identity scheme.
1315 if ((peer = findpeerbyassoc(ep->pkt[0])) == NULL) {
1319 if ((rval = crypto_alice(peer, &vtemp)) == XEVNT_OK) {
1320 len += crypto_send(fp, &vtemp);
1326 * Send response in Schnorr (IFF) identity scheme.
1328 case CRYPTO_IFF | CRYPTO_RESP:
1329 if ((rval = crypto_bob(ep, &vtemp)) == XEVNT_OK) {
1330 len += crypto_send(fp, &vtemp);
1336 * Send challenge in Guillou-Quisquater (GQ) identity scheme.
1339 if ((peer = findpeerbyassoc(ep->pkt[0])) == NULL) {
1343 if ((rval = crypto_alice2(peer, &vtemp)) == XEVNT_OK) {
1344 len += crypto_send(fp, &vtemp);
1350 * Send response in Guillou-Quisquater (GQ) identity scheme.
1352 case CRYPTO_GQ | CRYPTO_RESP:
1353 if ((rval = crypto_bob2(ep, &vtemp)) == XEVNT_OK) {
1354 len += crypto_send(fp, &vtemp);
1360 * Send challenge in MV identity scheme.
1363 if ((peer = findpeerbyassoc(ep->pkt[0])) == NULL) {
1367 if ((rval = crypto_alice3(peer, &vtemp)) == XEVNT_OK) {
1368 len += crypto_send(fp, &vtemp);
1374 * Send response in MV identity scheme.
1376 case CRYPTO_MV | CRYPTO_RESP:
1377 if ((rval = crypto_bob3(ep, &vtemp)) == XEVNT_OK) {
1378 len += crypto_send(fp, &vtemp);
1384 * Send certificate sign response. The integrity of the request
1385 * certificate has already been verified on the receive side.
1386 * Sign the response using the local server key. Use the
1387 * filestamp from the request and use the timestamp as the
1388 * current time. Light the error bit if the certificate is
1389 * invalid or contains an unverified signature.
1391 case CRYPTO_SIGN | CRYPTO_RESP:
1392 if ((rval = cert_sign(ep, &vtemp)) == XEVNT_OK)
1393 len += crypto_send(fp, &vtemp);
1398 * Send public key and signature. Use the values from the public
1402 len += crypto_send(fp, &pubkey);
1406 * Encrypt and send cookie and signature. Light the error bit if
1407 * anything goes wrong.
1409 case CRYPTO_COOK | CRYPTO_RESP:
1410 if ((opcode & 0xffff) < VALUE_LEN) {
1414 if (PKT_MODE(xpkt->li_vn_mode) == MODE_SERVER) {
1417 if ((peer = findpeerbyassoc(associd)) == NULL) {
1421 tcookie = peer->pcookie;
1423 if ((rval = crypto_encrypt(ep, &vtemp, &tcookie)) ==
1425 len += crypto_send(fp, &vtemp);
1430 * Find peer and send autokey data and signature in broadcast
1431 * server and symmetric modes. Use the values in the autokey
1432 * structure. If no association is found, either the server has
1433 * restarted with new associations or some perp has replayed an
1434 * old message, in which case light the error bit.
1436 case CRYPTO_AUTO | CRYPTO_RESP:
1437 if ((peer = findpeerbyassoc(associd)) == NULL) {
1441 peer->flags &= ~FLAG_ASSOC;
1442 len += crypto_send(fp, &peer->sndval);
1446 * Send leapseconds table and signature. Use the values from the
1447 * tai structure. If no table has been loaded, just send an
1451 case CRYPTO_TAI | CRYPTO_RESP:
1452 if (crypto_flags & CRYPTO_FLAG_TAI)
1453 len += crypto_send(fp, &tai_leap);
1457 * Default - Fall through for requests; for unknown responses,
1461 if (opcode & CRYPTO_RESP)
1466 * In case of error, flame the log. If a request, toss the
1467 * puppy; if a response, return so the sender can flame, too.
1469 if (rval != XEVNT_OK) {
1470 opcode |= CRYPTO_ERROR;
1471 snprintf(statstr, NTP_MAXSTRLEN,
1472 "error %x opcode %x", rval, opcode);
1473 record_crypto_stats(srcadr_sin, statstr);
1474 report_event(rval, NULL);
1477 printf("crypto_xmit: %s\n", statstr);
1479 if (!(opcode & CRYPTO_RESP))
1484 * Round up the field length to a multiple of 8 bytes and save
1485 * the request code and length.
1487 len = ((len + 7) / 8) * 8;
1488 fp->opcode = htonl((opcode & 0xffff0000) | len);
1492 "crypto_xmit: flags 0x%x ext offset %d len %u code 0x%x assocID %d\n",
1493 crypto_flags, start, len, opcode >> 16, associd);
1500 * crypto_verify - parse and verify the extension field and value
1504 * XEVNT_LEN bad field format or length
1505 * XEVNT_TSP bad timestamp
1506 * XEVNT_FSP bad filestamp
1507 * XEVNT_PUB bad or missing public key
1508 * XEVNT_SGL bad signature length
1509 * XEVNT_SIG signature not verified
1510 * XEVNT_ERR protocol error
1514 struct exten *ep, /* extension pointer */
1515 struct value *vp, /* value pointer */
1516 struct peer *peer /* peer structure pointer */
1519 EVP_PKEY *pkey; /* server public key */
1520 EVP_MD_CTX ctx; /* signature context */
1521 tstamp_t tstamp, tstamp1 = 0; /* timestamp */
1522 tstamp_t fstamp, fstamp1 = 0; /* filestamp */
1523 u_int vallen; /* value length */
1524 u_int siglen; /* signature length */
1529 * We require valid opcode and field lengths, timestamp,
1530 * filestamp, public key, digest, signature length and
1531 * signature, where relevant. Note that preliminary length
1532 * checks are done in the main loop.
1534 len = ntohl(ep->opcode) & 0x0000ffff;
1535 opcode = ntohl(ep->opcode) & 0xffff0000;
1538 * Check for valid operation code and protocol. The opcode must
1539 * not have the error bit set. If a response, it must have a
1540 * value header. If a request and does not contain a value
1541 * header, no need for further checking.
1543 if (opcode & CRYPTO_ERROR)
1546 if (opcode & CRYPTO_RESP) {
1547 if (len < VALUE_LEN)
1550 if (len < VALUE_LEN)
1555 * We have a value header. Check for valid field lengths. The
1556 * field length must be long enough to contain the value header,
1557 * value and signature. Note both the value and signature fields
1558 * are rounded up to the next word.
1560 vallen = ntohl(ep->vallen);
1561 i = (vallen + 3) / 4;
1562 siglen = ntohl(ep->pkt[i++]);
1563 if (len < VALUE_LEN + ((vallen + 3) / 4) * 4 + ((siglen + 3) /
1568 * Punt if this is a response with no data. Punt if this is a
1569 * request and a previous response is pending.
1571 if (opcode & CRYPTO_RESP) {
1575 if (peer->cmmd != NULL)
1580 * Check for valid timestamp and filestamp. If the timestamp is
1581 * zero, the sender is not synchronized and signatures are
1582 * disregarded. If not, the timestamp must not precede the
1583 * filestamp. The timestamp and filestamp must not precede the
1584 * corresponding values in the value structure, if present. Once
1585 * the autokey values have been installed, the timestamp must
1586 * always be later than the corresponding value in the value
1587 * structure. Duplicate timestamps are illegal once the cookie
1588 * has been validated.
1590 tstamp = ntohl(ep->tstamp);
1591 fstamp = ntohl(ep->fstamp);
1595 if (tstamp < fstamp)
1599 tstamp1 = ntohl(vp->tstamp);
1600 fstamp1 = ntohl(vp->fstamp);
1601 if ((tstamp < tstamp1 || (tstamp == tstamp1 &&
1602 (peer->crypto & CRYPTO_FLAG_AUTO))))
1605 if ((tstamp < fstamp1 || fstamp < fstamp1))
1610 * Check for valid signature length, public key and digest
1613 if (crypto_flags & peer->crypto & CRYPTO_FLAG_PRIV)
1617 if (siglen == 0 || pkey == NULL || peer->digest == NULL)
1620 if (siglen != (u_int)EVP_PKEY_size(pkey))
1624 * Darn, I thought we would never get here. Verify the
1625 * signature. If the identity exchange is verified, light the
1626 * proventic bit. If no client identity scheme is specified,
1627 * avoid doing the sign exchange.
1629 EVP_VerifyInit(&ctx, peer->digest);
1630 EVP_VerifyUpdate(&ctx, (u_char *)&ep->tstamp, vallen + 12);
1631 if (EVP_VerifyFinal(&ctx, (u_char *)&ep->pkt[i], siglen, pkey) <= 0)
1634 if (peer->crypto & CRYPTO_FLAG_VRFY) {
1635 peer->crypto |= CRYPTO_FLAG_PROV;
1636 if (!(crypto_flags & CRYPTO_FLAG_MASK))
1637 peer->crypto |= CRYPTO_FLAG_SIGN;
1644 * crypto_encrypt - construct encrypted cookie and signature from
1645 * extension field and cookie
1649 * XEVNT_PUB bad or missing public key
1650 * XEVNT_CKY bad or missing cookie
1651 * XEVNT_PER host certificate expired
1655 struct exten *ep, /* extension pointer */
1656 struct value *vp, /* value pointer */
1657 keyid_t *cookie /* server cookie */
1660 EVP_PKEY *pkey; /* public key */
1661 EVP_MD_CTX ctx; /* signature context */
1662 tstamp_t tstamp; /* NTP timestamp */
1668 * Extract the public key from the request.
1670 len = ntohl(ep->vallen);
1671 ptr = (u_char *)ep->pkt;
1672 pkey = d2i_PublicKey(EVP_PKEY_RSA, NULL, &ptr, len);
1674 msyslog(LOG_ERR, "crypto_encrypt %s\n",
1675 ERR_error_string(ERR_get_error(), NULL));
1680 * Encrypt the cookie, encode in ASN.1 and sign.
1682 tstamp = crypto_time();
1683 memset(vp, 0, sizeof(struct value));
1684 vp->tstamp = htonl(tstamp);
1685 vp->fstamp = hostval.tstamp;
1686 len = EVP_PKEY_size(pkey);
1687 vp->vallen = htonl(len);
1688 vp->ptr = emalloc(len);
1689 temp32 = htonl(*cookie);
1690 if (!RSA_public_encrypt(4, (u_char *)&temp32, vp->ptr,
1691 pkey->pkey.rsa, RSA_PKCS1_OAEP_PADDING)) {
1692 msyslog(LOG_ERR, "crypto_encrypt %s\n",
1693 ERR_error_string(ERR_get_error(), NULL));
1694 EVP_PKEY_free(pkey);
1697 EVP_PKEY_free(pkey);
1702 if (tstamp < cinfo->first || tstamp > cinfo->last)
1705 vp->sig = emalloc(sign_siglen);
1706 EVP_SignInit(&ctx, sign_digest);
1707 EVP_SignUpdate(&ctx, (u_char *)&vp->tstamp, 12);
1708 EVP_SignUpdate(&ctx, vp->ptr, len);
1709 if (EVP_SignFinal(&ctx, vp->sig, &len, sign_pkey))
1710 vp->siglen = htonl(len);
1716 * crypto_ident - construct extension field for identity scheme
1718 * This routine determines which identity scheme is in use and
1719 * constructs an extension field for that scheme.
1723 struct peer *peer /* peer structure pointer */
1726 char filename[MAXFILENAME + 1];
1729 * If the server identity has already been verified, no further
1730 * action is necessary. Otherwise, try to load the identity file
1731 * of the certificate issuer. If the issuer file is not found,
1732 * try the host file. If nothing found, declare a cryptobust.
1733 * Note we can't get here unless the trusted certificate has
1734 * been found and the CRYPTO_FLAG_VALID bit is set, so the
1735 * certificate issuer is valid.
1737 if (peer->ident_pkey != NULL)
1738 EVP_PKEY_free(peer->ident_pkey);
1739 if (peer->crypto & CRYPTO_FLAG_GQ) {
1740 snprintf(filename, MAXFILENAME, "ntpkey_gq_%s",
1742 peer->ident_pkey = crypto_key(filename, &peer->fstamp);
1743 if (peer->ident_pkey != NULL)
1746 snprintf(filename, MAXFILENAME, "ntpkey_gq_%s",
1748 peer->ident_pkey = crypto_key(filename, &peer->fstamp);
1749 if (peer->ident_pkey != NULL)
1752 if (peer->crypto & CRYPTO_FLAG_IFF) {
1753 snprintf(filename, MAXFILENAME, "ntpkey_iff_%s",
1755 peer->ident_pkey = crypto_key(filename, &peer->fstamp);
1756 if (peer->ident_pkey != NULL)
1757 return (CRYPTO_IFF);
1759 snprintf(filename, MAXFILENAME, "ntpkey_iff_%s",
1761 peer->ident_pkey = crypto_key(filename, &peer->fstamp);
1762 if (peer->ident_pkey != NULL)
1763 return (CRYPTO_IFF);
1765 if (peer->crypto & CRYPTO_FLAG_MV) {
1766 snprintf(filename, MAXFILENAME, "ntpkey_mv_%s",
1768 peer->ident_pkey = crypto_key(filename, &peer->fstamp);
1769 if (peer->ident_pkey != NULL)
1772 snprintf(filename, MAXFILENAME, "ntpkey_mv_%s",
1774 peer->ident_pkey = crypto_key(filename, &peer->fstamp);
1775 if (peer->ident_pkey != NULL)
1780 * No compatible identity scheme is available. Life is hard.
1783 "crypto_ident: no compatible identity scheme found");
1789 * crypto_args - construct extension field from arguments
1791 * This routine creates an extension field with current timestamps and
1792 * specified opcode, association ID and optional string. Note that the
1793 * extension field is created here, but freed after the crypto_xmit()
1794 * call in the protocol module.
1796 * Returns extension field pointer (no errors).
1800 struct peer *peer, /* peer structure pointer */
1801 u_int opcode, /* operation code */
1802 char *str /* argument string */
1805 tstamp_t tstamp; /* NTP timestamp */
1806 struct exten *ep; /* extension field pointer */
1807 u_int len; /* extension field length */
1809 tstamp = crypto_time();
1810 len = sizeof(struct exten);
1818 ep->opcode = htonl(opcode + len);
1821 * If a response, send our ID; if a request, send the
1824 if (opcode & CRYPTO_RESP)
1825 ep->associd = htonl(peer->associd);
1827 ep->associd = htonl(peer->assoc);
1828 ep->tstamp = htonl(tstamp);
1829 ep->fstamp = hostval.tstamp;
1832 ep->vallen = htonl(strlen(str));
1833 memcpy((char *)ep->pkt, str, strlen(str));
1835 ep->pkt[0] = peer->associd;
1842 * crypto_send - construct extension field from value components
1844 * Returns extension field length. Note: it is not polite to send a
1845 * nonempty signature with zero timestamp or a nonzero timestamp with
1846 * empty signature, but these rules are not enforced here.
1850 struct exten *ep, /* extension field pointer */
1851 struct value *vp /* value pointer */
1858 * Copy data. If the data field is empty or zero length, encode
1859 * an empty value with length zero.
1861 ep->tstamp = vp->tstamp;
1862 ep->fstamp = vp->fstamp;
1863 ep->vallen = vp->vallen;
1865 temp32 = ntohl(vp->vallen);
1866 if (temp32 > 0 && vp->ptr != NULL)
1867 memcpy(ep->pkt, vp->ptr, temp32);
1870 * Copy signature. If the signature field is empty or zero
1871 * length, encode an empty signature with length zero.
1873 i = (temp32 + 3) / 4;
1875 ep->pkt[i++] = vp->siglen;
1876 temp32 = ntohl(vp->siglen);
1877 if (temp32 > 0 && vp->sig != NULL)
1878 memcpy(&ep->pkt[i], vp->sig, temp32);
1885 * crypto_update - compute new public value and sign extension fields
1887 * This routine runs periodically, like once a day, and when something
1888 * changes. It updates the timestamps on three value structures and one
1889 * value structure list, then signs all the structures:
1891 * hostval host name (not signed)
1893 * cinfo certificate info/value list
1894 * tai_leap leapseconds file
1896 * Filestamps are proventicated data, so this routine is run only when
1897 * the host has been synchronized to a proventicated source. Thus, the
1898 * timestamp is proventicated, too, and can be used to deflect
1899 * clogging attacks and even cook breakfast.
1901 * Returns void (no errors)
1906 EVP_MD_CTX ctx; /* message digest context */
1907 struct cert_info *cp, *cpn; /* certificate info/value */
1908 char statstr[NTP_MAXSTRLEN]; /* statistics for filegen */
1909 tstamp_t tstamp; /* NTP timestamp */
1912 if ((tstamp = crypto_time()) == 0)
1915 hostval.tstamp = htonl(tstamp);
1918 * Sign public key and timestamps. The filestamp is derived from
1919 * the host key file extension from wherever the file was
1922 if (pubkey.vallen != 0) {
1923 pubkey.tstamp = hostval.tstamp;
1925 if (pubkey.sig == NULL)
1926 pubkey.sig = emalloc(sign_siglen);
1927 EVP_SignInit(&ctx, sign_digest);
1928 EVP_SignUpdate(&ctx, (u_char *)&pubkey, 12);
1929 EVP_SignUpdate(&ctx, pubkey.ptr, ntohl(pubkey.vallen));
1930 if (EVP_SignFinal(&ctx, pubkey.sig, &len, sign_pkey))
1931 pubkey.siglen = htonl(len);
1935 * Sign certificates and timestamps. The filestamp is derived
1936 * from the certificate file extension from wherever the file
1937 * was generated. Note we do not throw expired certificates
1938 * away; they may have signed younger ones.
1940 for (cp = cinfo; cp != NULL; cp = cpn) {
1942 cp->cert.tstamp = hostval.tstamp;
1943 cp->cert.siglen = 0;
1944 if (cp->cert.sig == NULL)
1945 cp->cert.sig = emalloc(sign_siglen);
1946 EVP_SignInit(&ctx, sign_digest);
1947 EVP_SignUpdate(&ctx, (u_char *)&cp->cert, 12);
1948 EVP_SignUpdate(&ctx, cp->cert.ptr,
1949 ntohl(cp->cert.vallen));
1950 if (EVP_SignFinal(&ctx, cp->cert.sig, &len, sign_pkey))
1951 cp->cert.siglen = htonl(len);
1955 * Sign leapseconds table and timestamps. The filestamp is
1956 * derived from the leapsecond file extension from wherever the
1957 * file was generated.
1959 if (tai_leap.vallen != 0) {
1960 tai_leap.tstamp = hostval.tstamp;
1961 tai_leap.siglen = 0;
1962 if (tai_leap.sig == NULL)
1963 tai_leap.sig = emalloc(sign_siglen);
1964 EVP_SignInit(&ctx, sign_digest);
1965 EVP_SignUpdate(&ctx, (u_char *)&tai_leap, 12);
1966 EVP_SignUpdate(&ctx, tai_leap.ptr,
1967 ntohl(tai_leap.vallen));
1968 if (EVP_SignFinal(&ctx, tai_leap.sig, &len, sign_pkey))
1969 tai_leap.siglen = htonl(len);
1971 snprintf(statstr, NTP_MAXSTRLEN,
1972 "update ts %u", ntohl(hostval.tstamp));
1973 record_crypto_stats(NULL, statstr);
1976 printf("crypto_update: %s\n", statstr);
1982 * value_free - free value structure components.
1984 * Returns void (no errors)
1988 struct value *vp /* value structure */
1991 if (vp->ptr != NULL)
1993 if (vp->sig != NULL)
1995 memset(vp, 0, sizeof(struct value));
2000 * crypto_time - returns current NTP time in seconds.
2005 l_fp tstamp; /* NTP time */ L_CLR(&tstamp);
2008 if (sys_leap != LEAP_NOTINSYNC)
2009 get_systime(&tstamp);
2010 return (tstamp.l_ui);
2015 * asn2ntp - convert ASN1_TIME time structure to NTP time in seconds.
2019 ASN1_TIME *asn1time /* pointer to ASN1_TIME structure */
2022 char *v; /* pointer to ASN1_TIME string */
2023 struct tm tm; /* used to convert to NTP time */
2026 * Extract time string YYMMDDHHMMSSZ from ASN1 time structure.
2027 * Note that the YY, MM, DD fields start with one, the HH, MM,
2028 * SS fiels start with zero and the Z character should be 'Z'
2029 * for UTC. Also note that years less than 50 map to years
2030 * greater than 100. Dontcha love ASN.1? Better than MIL-188.
2032 if (asn1time->length > 13)
2033 return ((u_long)(~0)); /* We can't use -1 here. It's invalid */
2035 v = (char *)asn1time->data;
2036 tm.tm_year = (v[0] - '0') * 10 + v[1] - '0';
2037 if (tm.tm_year < 50)
2039 tm.tm_mon = (v[2] - '0') * 10 + v[3] - '0' - 1;
2040 tm.tm_mday = (v[4] - '0') * 10 + v[5] - '0';
2041 tm.tm_hour = (v[6] - '0') * 10 + v[7] - '0';
2042 tm.tm_min = (v[8] - '0') * 10 + v[9] - '0';
2043 tm.tm_sec = (v[10] - '0') * 10 + v[11] - '0';
2047 return (timegm(&tm) + JAN_1970);
2052 * bigdig() - compute a BIGNUM MD5 hash of a BIGNUM number.
2056 BIGNUM *bn, /* BIGNUM * from */
2057 BIGNUM *bk /* BIGNUM * to */
2060 EVP_MD_CTX ctx; /* message digest context */
2061 u_char dgst[EVP_MAX_MD_SIZE]; /* message digest */
2062 u_char *ptr; /* a BIGNUM as binary string */
2065 len = BN_num_bytes(bn);
2068 EVP_DigestInit(&ctx, EVP_md5());
2069 EVP_DigestUpdate(&ctx, ptr, len);
2070 EVP_DigestFinal(&ctx, dgst, &len);
2071 BN_bin2bn(dgst, len, bk);
2073 /* XXX MEMLEAK? free ptr? */
2080 ***********************************************************************
2082 * The following routines implement the Schnorr (IFF) identity scheme *
2084 ***********************************************************************
2086 * The Schnorr (IFF) identity scheme is intended for use when
2087 * the ntp-genkeys program does not generate the certificates used in
2088 * the protocol and the group key cannot be conveyed in the certificate
2089 * itself. For this purpose, new generations of IFF values must be
2090 * securely transmitted to all members of the group before use. The
2091 * scheme is self contained and independent of new generations of host
2092 * keys, sign keys and certificates.
2094 * The IFF identity scheme is based on DSA cryptography and algorithms
2095 * described in Stinson p. 285. The IFF values hide in a DSA cuckoo
2096 * structure, but only the primes and generator are used. The p is a
2097 * 512-bit prime, q a 160-bit prime that divides p - 1 and is a qth root
2098 * of 1 mod p; that is, g^q = 1 mod p. The TA rolls primvate random
2099 * group key b disguised as a DSA structure member, then computes public
2100 * key g^(q - b). These values are shared only among group members and
2101 * never revealed in messages. Alice challenges Bob to confirm identity
2102 * using the protocol described below.
2106 * The scheme goes like this. Both Alice and Bob have the public primes
2107 * p, q and generator g. The TA gives private key b to Bob and public
2108 * key v = g^(q - a) mod p to Alice.
2110 * Alice rolls new random challenge r and sends to Bob in the IFF
2111 * request message. Bob rolls new random k, then computes y = k + b r
2112 * mod q and x = g^k mod p and sends (y, hash(x)) to Alice in the
2113 * response message. Besides making the response shorter, the hash makes
2114 * it effectivey impossible for an intruder to solve for b by observing
2115 * a number of these messages.
2117 * Alice receives the response and computes g^y v^r mod p. After a bit
2118 * of algebra, this simplifies to g^k. If the hash of this result
2119 * matches hash(x), Alice knows that Bob has the group key b. The signed
2120 * response binds this knowledge to Bob's private key and the public key
2121 * previously received in his certificate.
2123 * crypto_alice - construct Alice's challenge in IFF scheme
2127 * XEVNT_PUB bad or missing public key
2128 * XEVNT_ID bad or missing group key
2132 struct peer *peer, /* peer pointer */
2133 struct value *vp /* value pointer */
2136 DSA *dsa; /* IFF parameters */
2137 BN_CTX *bctx; /* BIGNUM context */
2138 EVP_MD_CTX ctx; /* signature context */
2143 * The identity parameters must have correct format and content.
2145 if (peer->ident_pkey == NULL)
2148 if ((dsa = peer->ident_pkey->pkey.dsa) == NULL) {
2149 msyslog(LOG_INFO, "crypto_alice: defective key");
2154 * Roll new random r (0 < r < q). The OpenSSL library has a bug
2155 * omitting BN_rand_range, so we have to do it the hard way.
2157 bctx = BN_CTX_new();
2158 len = BN_num_bytes(dsa->q);
2159 if (peer->iffval != NULL)
2160 BN_free(peer->iffval);
2161 peer->iffval = BN_new();
2162 BN_rand(peer->iffval, len * 8, -1, 1); /* r */
2163 BN_mod(peer->iffval, peer->iffval, dsa->q, bctx);
2167 * Sign and send to Bob. The filestamp is from the local file.
2169 tstamp = crypto_time();
2170 memset(vp, 0, sizeof(struct value));
2171 vp->tstamp = htonl(tstamp);
2172 vp->fstamp = htonl(peer->fstamp);
2173 vp->vallen = htonl(len);
2174 vp->ptr = emalloc(len);
2175 BN_bn2bin(peer->iffval, vp->ptr);
2180 if (tstamp < cinfo->first || tstamp > cinfo->last)
2183 vp->sig = emalloc(sign_siglen);
2184 EVP_SignInit(&ctx, sign_digest);
2185 EVP_SignUpdate(&ctx, (u_char *)&vp->tstamp, 12);
2186 EVP_SignUpdate(&ctx, vp->ptr, len);
2187 if (EVP_SignFinal(&ctx, vp->sig, &len, sign_pkey))
2188 vp->siglen = htonl(len);
2194 * crypto_bob - construct Bob's response to Alice's challenge
2198 * XEVNT_ID bad or missing group key
2199 * XEVNT_ERR protocol error
2200 * XEVNT_PER host expired certificate
2204 struct exten *ep, /* extension pointer */
2205 struct value *vp /* value pointer */
2208 DSA *dsa; /* IFF parameters */
2209 DSA_SIG *sdsa; /* DSA signature context fake */
2210 BN_CTX *bctx; /* BIGNUM context */
2211 EVP_MD_CTX ctx; /* signature context */
2212 tstamp_t tstamp; /* NTP timestamp */
2213 BIGNUM *bn, *bk, *r;
2218 * If the IFF parameters are not valid, something awful
2219 * happened or we are being tormented.
2221 if (iffpar_pkey == NULL) {
2222 msyslog(LOG_INFO, "crypto_bob: scheme unavailable");
2225 dsa = iffpar_pkey->pkey.dsa;
2228 * Extract r from the challenge.
2230 len = ntohl(ep->vallen);
2231 if ((r = BN_bin2bn((u_char *)ep->pkt, len, NULL)) == NULL) {
2232 msyslog(LOG_ERR, "crypto_bob %s\n",
2233 ERR_error_string(ERR_get_error(), NULL));
2238 * Bob rolls random k (0 < k < q), computes y = k + b r mod q
2239 * and x = g^k mod p, then sends (y, hash(x)) to Alice.
2241 bctx = BN_CTX_new(); bk = BN_new(); bn = BN_new();
2242 sdsa = DSA_SIG_new();
2243 BN_rand(bk, len * 8, -1, 1); /* k */
2244 BN_mod_mul(bn, dsa->priv_key, r, dsa->q, bctx); /* b r mod q */
2246 BN_mod(bn, bn, dsa->q, bctx); /* k + b r mod q */
2247 sdsa->r = BN_dup(bn);
2248 BN_mod_exp(bk, dsa->g, bk, dsa->p, bctx); /* g^k mod p */
2250 sdsa->s = BN_dup(bk);
2252 BN_free(r); BN_free(bn); BN_free(bk);
2255 * Encode the values in ASN.1 and sign.
2257 tstamp = crypto_time();
2258 memset(vp, 0, sizeof(struct value));
2259 vp->tstamp = htonl(tstamp);
2260 vp->fstamp = htonl(if_fstamp);
2261 len = i2d_DSA_SIG(sdsa, NULL);
2263 msyslog(LOG_ERR, "crypto_bob %s\n",
2264 ERR_error_string(ERR_get_error(), NULL));
2268 vp->vallen = htonl(len);
2271 i2d_DSA_SIG(sdsa, &ptr);
2277 if (tstamp < cinfo->first || tstamp > cinfo->last)
2280 vp->sig = emalloc(sign_siglen);
2281 EVP_SignInit(&ctx, sign_digest);
2282 EVP_SignUpdate(&ctx, (u_char *)&vp->tstamp, 12);
2283 EVP_SignUpdate(&ctx, vp->ptr, len);
2284 if (EVP_SignFinal(&ctx, vp->sig, &len, sign_pkey))
2285 vp->siglen = htonl(len);
2291 * crypto_iff - verify Bob's response to Alice's challenge
2295 * XEVNT_PUB bad or missing public key
2296 * XEVNT_ID bad or missing group key
2297 * XEVNT_FSP bad filestamp
2301 struct exten *ep, /* extension pointer */
2302 struct peer *peer /* peer structure pointer */
2305 DSA *dsa; /* IFF parameters */
2306 BN_CTX *bctx; /* BIGNUM context */
2307 DSA_SIG *sdsa; /* DSA parameters */
2314 * If the IFF parameters are not valid or no challenge was sent,
2315 * something awful happened or we are being tormented.
2317 if (peer->ident_pkey == NULL) {
2318 msyslog(LOG_INFO, "crypto_iff: scheme unavailable");
2321 if (ntohl(ep->fstamp) != peer->fstamp) {
2322 msyslog(LOG_INFO, "crypto_iff: invalid filestamp %u",
2326 if ((dsa = peer->ident_pkey->pkey.dsa) == NULL) {
2327 msyslog(LOG_INFO, "crypto_iff: defective key");
2330 if (peer->iffval == NULL) {
2331 msyslog(LOG_INFO, "crypto_iff: missing challenge");
2336 * Extract the k + b r and g^k values from the response.
2338 bctx = BN_CTX_new(); bk = BN_new(); bn = BN_new();
2339 len = ntohl(ep->vallen);
2340 ptr = (const u_char *)ep->pkt;
2341 if ((sdsa = d2i_DSA_SIG(NULL, &ptr, len)) == NULL) {
2342 msyslog(LOG_ERR, "crypto_iff %s\n",
2343 ERR_error_string(ERR_get_error(), NULL));
2348 * Compute g^(k + b r) g^(q - b)r mod p.
2350 BN_mod_exp(bn, dsa->pub_key, peer->iffval, dsa->p, bctx);
2351 BN_mod_exp(bk, dsa->g, sdsa->r, dsa->p, bctx);
2352 BN_mod_mul(bn, bn, bk, dsa->p, bctx);
2355 * Verify the hash of the result matches hash(x).
2358 temp = BN_cmp(bn, sdsa->s);
2359 BN_free(bn); BN_free(bk); BN_CTX_free(bctx);
2360 BN_free(peer->iffval);
2361 peer->iffval = NULL;
2372 ***********************************************************************
2374 * The following routines implement the Guillou-Quisquater (GQ) *
2377 ***********************************************************************
2379 * The Guillou-Quisquater (GQ) identity scheme is intended for use when
2380 * the ntp-genkeys program generates the certificates used in the
2381 * protocol and the group key can be conveyed in a certificate extension
2382 * field. The scheme is self contained and independent of new
2383 * generations of host keys, sign keys and certificates.
2385 * The GQ identity scheme is based on RSA cryptography and algorithms
2386 * described in Stinson p. 300 (with errors). The GQ values hide in a
2387 * RSA cuckoo structure, but only the modulus is used. The 512-bit
2388 * public modulus is n = p q, where p and q are secret large primes. The
2389 * TA rolls random group key b disguised as a RSA structure member.
2390 * Except for the public key, these values are shared only among group
2391 * members and never revealed in messages.
2393 * When rolling new certificates, Bob recomputes the private and
2394 * public keys. The private key u is a random roll, while the public key
2395 * is the inverse obscured by the group key v = (u^-1)^b. These values
2396 * replace the private and public keys normally generated by the RSA
2397 * scheme. Alice challenges Bob to confirm identity using the protocol
2402 * The scheme goes like this. Both Alice and Bob have the same modulus n
2403 * and some random b as the group key. These values are computed and
2404 * distributed in advance via secret means, although only the group key
2405 * b is truly secret. Each has a private random private key u and public
2406 * key (u^-1)^b, although not necessarily the same ones. Bob and Alice
2407 * can regenerate the key pair from time to time without affecting
2408 * operations. The public key is conveyed on the certificate in an
2409 * extension field; the private key is never revealed.
2411 * Alice rolls new random challenge r and sends to Bob in the GQ
2412 * request message. Bob rolls new random k, then computes y = k u^r mod
2413 * n and x = k^b mod n and sends (y, hash(x)) to Alice in the response
2414 * message. Besides making the response shorter, the hash makes it
2415 * effectivey impossible for an intruder to solve for b by observing
2416 * a number of these messages.
2418 * Alice receives the response and computes y^b v^r mod n. After a bit
2419 * of algebra, this simplifies to k^b. If the hash of this result
2420 * matches hash(x), Alice knows that Bob has the group key b. The signed
2421 * response binds this knowledge to Bob's private key and the public key
2422 * previously received in his certificate.
2424 * crypto_alice2 - construct Alice's challenge in GQ scheme
2428 * XEVNT_PUB bad or missing public key
2429 * XEVNT_ID bad or missing group key
2430 * XEVNT_PER host certificate expired
2434 struct peer *peer, /* peer pointer */
2435 struct value *vp /* value pointer */
2438 RSA *rsa; /* GQ parameters */
2439 BN_CTX *bctx; /* BIGNUM context */
2440 EVP_MD_CTX ctx; /* signature context */
2445 * The identity parameters must have correct format and content.
2447 if (peer->ident_pkey == NULL)
2450 if ((rsa = peer->ident_pkey->pkey.rsa) == NULL) {
2451 msyslog(LOG_INFO, "crypto_alice2: defective key");
2456 * Roll new random r (0 < r < n). The OpenSSL library has a bug
2457 * omitting BN_rand_range, so we have to do it the hard way.
2459 bctx = BN_CTX_new();
2460 len = BN_num_bytes(rsa->n);
2461 if (peer->iffval != NULL)
2462 BN_free(peer->iffval);
2463 peer->iffval = BN_new();
2464 BN_rand(peer->iffval, len * 8, -1, 1); /* r mod n */
2465 BN_mod(peer->iffval, peer->iffval, rsa->n, bctx);
2469 * Sign and send to Bob. The filestamp is from the local file.
2471 tstamp = crypto_time();
2472 memset(vp, 0, sizeof(struct value));
2473 vp->tstamp = htonl(tstamp);
2474 vp->fstamp = htonl(peer->fstamp);
2475 vp->vallen = htonl(len);
2476 vp->ptr = emalloc(len);
2477 BN_bn2bin(peer->iffval, vp->ptr);
2482 if (tstamp < cinfo->first || tstamp > cinfo->last)
2485 vp->sig = emalloc(sign_siglen);
2486 EVP_SignInit(&ctx, sign_digest);
2487 EVP_SignUpdate(&ctx, (u_char *)&vp->tstamp, 12);
2488 EVP_SignUpdate(&ctx, vp->ptr, len);
2489 if (EVP_SignFinal(&ctx, vp->sig, &len, sign_pkey))
2490 vp->siglen = htonl(len);
2496 * crypto_bob2 - construct Bob's response to Alice's challenge
2500 * XEVNT_ID bad or missing group key
2501 * XEVNT_ERR protocol error
2502 * XEVNT_PER host certificate expired
2506 struct exten *ep, /* extension pointer */
2507 struct value *vp /* value pointer */
2510 RSA *rsa; /* GQ parameters */
2511 DSA_SIG *sdsa; /* DSA parameters */
2512 BN_CTX *bctx; /* BIGNUM context */
2513 EVP_MD_CTX ctx; /* signature context */
2514 tstamp_t tstamp; /* NTP timestamp */
2515 BIGNUM *r, *k, *g, *y;
2520 * If the GQ parameters are not valid, something awful
2521 * happened or we are being tormented.
2523 if (gqpar_pkey == NULL) {
2524 msyslog(LOG_INFO, "crypto_bob2: scheme unavailable");
2527 rsa = gqpar_pkey->pkey.rsa;
2530 * Extract r from the challenge.
2532 len = ntohl(ep->vallen);
2533 if ((r = BN_bin2bn((u_char *)ep->pkt, len, NULL)) == NULL) {
2534 msyslog(LOG_ERR, "crypto_bob2 %s\n",
2535 ERR_error_string(ERR_get_error(), NULL));
2540 * Bob rolls random k (0 < k < n), computes y = k u^r mod n and
2541 * x = k^b mod n, then sends (y, hash(x)) to Alice.
2543 bctx = BN_CTX_new(); k = BN_new(); g = BN_new(); y = BN_new();
2544 sdsa = DSA_SIG_new();
2545 BN_rand(k, len * 8, -1, 1); /* k */
2546 BN_mod(k, k, rsa->n, bctx);
2547 BN_mod_exp(y, rsa->p, r, rsa->n, bctx); /* u^r mod n */
2548 BN_mod_mul(y, k, y, rsa->n, bctx); /* k u^r mod n */
2549 sdsa->r = BN_dup(y);
2550 BN_mod_exp(g, k, rsa->e, rsa->n, bctx); /* k^b mod n */
2552 sdsa->s = BN_dup(g);
2554 BN_free(r); BN_free(k); BN_free(g); BN_free(y);
2557 * Encode the values in ASN.1 and sign.
2559 tstamp = crypto_time();
2560 memset(vp, 0, sizeof(struct value));
2561 vp->tstamp = htonl(tstamp);
2562 vp->fstamp = htonl(gq_fstamp);
2563 len = i2d_DSA_SIG(sdsa, NULL);
2565 msyslog(LOG_ERR, "crypto_bob2 %s\n",
2566 ERR_error_string(ERR_get_error(), NULL));
2570 vp->vallen = htonl(len);
2573 i2d_DSA_SIG(sdsa, &ptr);
2579 if (tstamp < cinfo->first || tstamp > cinfo->last)
2582 vp->sig = emalloc(sign_siglen);
2583 EVP_SignInit(&ctx, sign_digest);
2584 EVP_SignUpdate(&ctx, (u_char *)&vp->tstamp, 12);
2585 EVP_SignUpdate(&ctx, vp->ptr, len);
2586 if (EVP_SignFinal(&ctx, vp->sig, &len, sign_pkey))
2587 vp->siglen = htonl(len);
2593 * crypto_gq - verify Bob's response to Alice's challenge
2597 * XEVNT_PUB bad or missing public key
2598 * XEVNT_ID bad or missing group keys
2599 * XEVNT_ERR protocol error
2600 * XEVNT_FSP bad filestamp
2604 struct exten *ep, /* extension pointer */
2605 struct peer *peer /* peer structure pointer */
2608 RSA *rsa; /* GQ parameters */
2609 BN_CTX *bctx; /* BIGNUM context */
2610 DSA_SIG *sdsa; /* RSA signature context fake */
2617 * If the GQ parameters are not valid or no challenge was sent,
2618 * something awful happened or we are being tormented.
2620 if (peer->ident_pkey == NULL) {
2621 msyslog(LOG_INFO, "crypto_gq: scheme unavailable");
2624 if (ntohl(ep->fstamp) != peer->fstamp) {
2625 msyslog(LOG_INFO, "crypto_gq: invalid filestamp %u",
2629 if ((rsa = peer->ident_pkey->pkey.rsa) == NULL) {
2630 msyslog(LOG_INFO, "crypto_gq: defective key");
2633 if (peer->iffval == NULL) {
2634 msyslog(LOG_INFO, "crypto_gq: missing challenge");
2639 * Extract the y = k u^r and hash(x = k^b) values from the
2642 bctx = BN_CTX_new(); y = BN_new(); v = BN_new();
2643 len = ntohl(ep->vallen);
2644 ptr = (const u_char *)ep->pkt;
2645 if ((sdsa = d2i_DSA_SIG(NULL, &ptr, len)) == NULL) {
2646 msyslog(LOG_ERR, "crypto_gq %s\n",
2647 ERR_error_string(ERR_get_error(), NULL));
2652 * Compute v^r y^b mod n.
2654 BN_mod_exp(v, peer->grpkey, peer->iffval, rsa->n, bctx);
2656 BN_mod_exp(y, sdsa->r, rsa->e, rsa->n, bctx); /* y^b mod n */
2657 BN_mod_mul(y, v, y, rsa->n, bctx); /* v^r y^b mod n */
2660 * Verify the hash of the result matches hash(x).
2663 temp = BN_cmp(y, sdsa->s);
2664 BN_CTX_free(bctx); BN_free(y); BN_free(v);
2665 BN_free(peer->iffval);
2666 peer->iffval = NULL;
2677 ***********************************************************************
2679 * The following routines implement the Mu-Varadharajan (MV) identity *
2682 ***********************************************************************
2685 * The Mu-Varadharajan (MV) cryptosystem was originally intended when
2686 * servers broadcast messages to clients, but clients never send
2687 * messages to servers. There is one encryption key for the server and a
2688 * separate decryption key for each client. It operated something like a
2689 * pay-per-view satellite broadcasting system where the session key is
2690 * encrypted by the broadcaster and the decryption keys are held in a
2691 * tamperproof set-top box.
2693 * The MV parameters and private encryption key hide in a DSA cuckoo
2694 * structure which uses the same parameters, but generated in a
2695 * different way. The values are used in an encryption scheme similar to
2696 * El Gamal cryptography and a polynomial formed from the expansion of
2697 * product terms (x - x[j]), as described in Mu, Y., and V.
2698 * Varadharajan: Robust and Secure Broadcasting, Proc. Indocrypt 2001,
2699 * 223-231. The paper has significant errors and serious omissions.
2701 * Let q be the product of n distinct primes s'[j] (j = 1...n), where
2702 * each s'[j] has m significant bits. Let p be a prime p = 2 * q + 1, so
2703 * that q and each s'[j] divide p - 1 and p has M = n * m + 1
2704 * significant bits. The elements x mod q of Zq with the elements 2 and
2705 * the primes removed form a field Zq* valid for polynomial arithetic.
2706 * Let g be a generator of Zp; that is, gcd(g, p - 1) = 1 and g^q = 1
2707 * mod p. We expect M to be in the 500-bit range and n relatively small,
2708 * like 25, so the likelihood of a randomly generated element of x mod q
2709 * of Zq colliding with a factor of p - 1 is very small and can be
2710 * avoided. Associated with each s'[j] is an element s[j] such that s[j]
2711 * s'[j] = s'[j] mod q. We find s[j] as the quotient (q + s'[j]) /
2712 * s'[j]. These are the parameters of the scheme and they are expensive
2715 * We set up an instance of the scheme as follows. A set of random
2716 * values x[j] mod q (j = 1...n), are generated as the zeros of a
2717 * polynomial of order n. The product terms (x - x[j]) are expanded to
2718 * form coefficients a[i] mod q (i = 0...n) in powers of x. These are
2719 * used as exponents of the generator g mod p to generate the private
2720 * encryption key A. The pair (gbar, ghat) of public server keys and the
2721 * pairs (xbar[j], xhat[j]) (j = 1...n) of private client keys are used
2722 * to construct the decryption keys. The devil is in the details.
2724 * The distinguishing characteristic of this scheme is the capability to
2725 * revoke keys. Included in the calculation of E, gbar and ghat is the
2726 * product s = prod(s'[j]) (j = 1...n) above. If the factor s'[j] is
2727 * subsequently removed from the product and E, gbar and ghat
2728 * recomputed, the jth client will no longer be able to compute E^-1 and
2729 * thus unable to decrypt the block.
2733 * The scheme goes like this. Bob has the server values (p, A, q, gbar,
2734 * ghat) and Alice the client values (p, xbar, xhat).
2736 * Alice rolls new random challenge r (0 < r < p) and sends to Bob in
2737 * the MV request message. Bob rolls new random k (0 < k < q), encrypts
2738 * y = A^k mod p (a permutation) and sends (hash(y), gbar^k, ghat^k) to
2741 * Alice receives the response and computes the decryption key (the
2742 * inverse permutation) from previously obtained (xbar, xhat) and
2743 * (gbar^k, ghat^k) in the message. She computes the inverse, which is
2744 * unique by reasons explained in the ntp-keygen.c program sources. If
2745 * the hash of this result matches hash(y), Alice knows that Bob has the
2746 * group key b. The signed response binds this knowledge to Bob's
2747 * private key and the public key previously received in his
2750 * crypto_alice3 - construct Alice's challenge in MV scheme
2754 * XEVNT_PUB bad or missing public key
2755 * XEVNT_ID bad or missing group key
2756 * XEVNT_PER host certificate expired
2760 struct peer *peer, /* peer pointer */
2761 struct value *vp /* value pointer */
2764 DSA *dsa; /* MV parameters */
2765 BN_CTX *bctx; /* BIGNUM context */
2766 EVP_MD_CTX ctx; /* signature context */
2771 * The identity parameters must have correct format and content.
2773 if (peer->ident_pkey == NULL)
2776 if ((dsa = peer->ident_pkey->pkey.dsa) == NULL) {
2777 msyslog(LOG_INFO, "crypto_alice3: defective key");
2782 * Roll new random r (0 < r < q). The OpenSSL library has a bug
2783 * omitting BN_rand_range, so we have to do it the hard way.
2785 bctx = BN_CTX_new();
2786 len = BN_num_bytes(dsa->p);
2787 if (peer->iffval != NULL)
2788 BN_free(peer->iffval);
2789 peer->iffval = BN_new();
2790 BN_rand(peer->iffval, len * 8, -1, 1); /* r */
2791 BN_mod(peer->iffval, peer->iffval, dsa->p, bctx);
2795 * Sign and send to Bob. The filestamp is from the local file.
2797 tstamp = crypto_time();
2798 memset(vp, 0, sizeof(struct value));
2799 vp->tstamp = htonl(tstamp);
2800 vp->fstamp = htonl(peer->fstamp);
2801 vp->vallen = htonl(len);
2802 vp->ptr = emalloc(len);
2803 BN_bn2bin(peer->iffval, vp->ptr);
2808 if (tstamp < cinfo->first || tstamp > cinfo->last)
2811 vp->sig = emalloc(sign_siglen);
2812 EVP_SignInit(&ctx, sign_digest);
2813 EVP_SignUpdate(&ctx, (u_char *)&vp->tstamp, 12);
2814 EVP_SignUpdate(&ctx, vp->ptr, len);
2815 if (EVP_SignFinal(&ctx, vp->sig, &len, sign_pkey))
2816 vp->siglen = htonl(len);
2822 * crypto_bob3 - construct Bob's response to Alice's challenge
2826 * XEVNT_ERR protocol error
2827 * XEVNT_PER host certificate expired
2831 struct exten *ep, /* extension pointer */
2832 struct value *vp /* value pointer */
2835 DSA *dsa; /* MV parameters */
2836 DSA *sdsa; /* DSA signature context fake */
2837 BN_CTX *bctx; /* BIGNUM context */
2838 EVP_MD_CTX ctx; /* signature context */
2839 tstamp_t tstamp; /* NTP timestamp */
2845 * If the MV parameters are not valid, something awful
2846 * happened or we are being tormented.
2848 if (mvpar_pkey == NULL) {
2849 msyslog(LOG_INFO, "crypto_bob3: scheme unavailable");
2852 dsa = mvpar_pkey->pkey.dsa;
2855 * Extract r from the challenge.
2857 len = ntohl(ep->vallen);
2858 if ((r = BN_bin2bn((u_char *)ep->pkt, len, NULL)) == NULL) {
2859 msyslog(LOG_ERR, "crypto_bob3 %s\n",
2860 ERR_error_string(ERR_get_error(), NULL));
2865 * Bob rolls random k (0 < k < q), making sure it is not a
2866 * factor of q. He then computes y = A^k r and sends (hash(y),
2867 * gbar^k, ghat^k) to Alice.
2869 bctx = BN_CTX_new(); k = BN_new(); u = BN_new();
2871 sdsa->p = BN_new(); sdsa->q = BN_new(); sdsa->g = BN_new();
2873 BN_rand(k, BN_num_bits(dsa->q), 0, 0);
2874 BN_mod(k, k, dsa->q, bctx);
2875 BN_gcd(u, k, dsa->q, bctx);
2879 BN_mod_exp(u, dsa->g, k, dsa->p, bctx); /* A r */
2880 BN_mod_mul(u, u, r, dsa->p, bctx);
2881 bighash(u, sdsa->p);
2882 BN_mod_exp(sdsa->q, dsa->priv_key, k, dsa->p, bctx); /* gbar */
2883 BN_mod_exp(sdsa->g, dsa->pub_key, k, dsa->p, bctx); /* ghat */
2884 BN_CTX_free(bctx); BN_free(k); BN_free(r); BN_free(u);
2887 * Encode the values in ASN.1 and sign.
2889 tstamp = crypto_time();
2890 memset(vp, 0, sizeof(struct value));
2891 vp->tstamp = htonl(tstamp);
2892 vp->fstamp = htonl(mv_fstamp);
2893 len = i2d_DSAparams(sdsa, NULL);
2895 msyslog(LOG_ERR, "crypto_bob3 %s\n",
2896 ERR_error_string(ERR_get_error(), NULL));
2900 vp->vallen = htonl(len);
2903 i2d_DSAparams(sdsa, &ptr);
2909 if (tstamp < cinfo->first || tstamp > cinfo->last)
2912 vp->sig = emalloc(sign_siglen);
2913 EVP_SignInit(&ctx, sign_digest);
2914 EVP_SignUpdate(&ctx, (u_char *)&vp->tstamp, 12);
2915 EVP_SignUpdate(&ctx, vp->ptr, len);
2916 if (EVP_SignFinal(&ctx, vp->sig, &len, sign_pkey))
2917 vp->siglen = htonl(len);
2923 * crypto_mv - verify Bob's response to Alice's challenge
2927 * XEVNT_PUB bad or missing public key
2928 * XEVNT_ID bad or missing group key
2929 * XEVNT_ERR protocol error
2930 * XEVNT_FSP bad filestamp
2934 struct exten *ep, /* extension pointer */
2935 struct peer *peer /* peer structure pointer */
2938 DSA *dsa; /* MV parameters */
2939 DSA *sdsa; /* DSA parameters */
2940 BN_CTX *bctx; /* BIGNUM context */
2947 * If the MV parameters are not valid or no challenge was sent,
2948 * something awful happened or we are being tormented.
2950 if (peer->ident_pkey == NULL) {
2951 msyslog(LOG_INFO, "crypto_mv: scheme unavailable");
2954 if (ntohl(ep->fstamp) != peer->fstamp) {
2955 msyslog(LOG_INFO, "crypto_mv: invalid filestamp %u",
2959 if ((dsa = peer->ident_pkey->pkey.dsa) == NULL) {
2960 msyslog(LOG_INFO, "crypto_mv: defective key");
2963 if (peer->iffval == NULL) {
2964 msyslog(LOG_INFO, "crypto_mv: missing challenge");
2969 * Extract the (hash(y), gbar, ghat) values from the response.
2971 bctx = BN_CTX_new(); k = BN_new(); u = BN_new(); v = BN_new();
2972 len = ntohl(ep->vallen);
2973 ptr = (const u_char *)ep->pkt;
2974 if ((sdsa = d2i_DSAparams(NULL, &ptr, len)) == NULL) {
2975 msyslog(LOG_ERR, "crypto_mv %s\n",
2976 ERR_error_string(ERR_get_error(), NULL));
2981 * Compute (gbar^xhat ghat^xbar)^-1 mod p.
2983 BN_mod_exp(u, sdsa->q, dsa->pub_key, dsa->p, bctx);
2984 BN_mod_exp(v, sdsa->g, dsa->priv_key, dsa->p, bctx);
2985 BN_mod_mul(u, u, v, dsa->p, bctx);
2986 BN_mod_inverse(u, u, dsa->p, bctx);
2987 BN_mod_mul(v, u, peer->iffval, dsa->p, bctx);
2990 * The result should match the hash of r mod p.
2993 temp = BN_cmp(v, sdsa->p);
2994 BN_CTX_free(bctx); BN_free(k); BN_free(u); BN_free(v);
2995 BN_free(peer->iffval);
2996 peer->iffval = NULL;
3007 ***********************************************************************
3009 * The following routines are used to manipulate certificates *
3011 ***********************************************************************
3014 * cert_parse - parse x509 certificate and create info/value structures.
3016 * The server certificate includes the version number, issuer name,
3017 * subject name, public key and valid date interval. If the issuer name
3018 * is the same as the subject name, the certificate is self signed and
3019 * valid only if the server is configured as trustable. If the names are
3020 * different, another issuer has signed the server certificate and
3021 * vouched for it. In this case the server certificate is valid if
3022 * verified by the issuer public key.
3024 * Returns certificate info/value pointer if valid, NULL if not.
3026 struct cert_info * /* certificate information structure */
3028 u_char *asn1cert, /* X509 certificate */
3029 u_int len, /* certificate length */
3030 tstamp_t fstamp /* filestamp */
3033 X509 *cert; /* X509 certificate */
3034 X509_EXTENSION *ext; /* X509v3 extension */
3035 struct cert_info *ret; /* certificate info/value */
3037 X509V3_EXT_METHOD *method;
3038 char pathbuf[MAXFILENAME];
3044 * Decode ASN.1 objects and construct certificate structure.
3047 if ((cert = d2i_X509(NULL, &uptr, len)) == NULL) {
3048 msyslog(LOG_ERR, "cert_parse %s\n",
3049 ERR_error_string(ERR_get_error(), NULL));
3054 * Extract version, subject name and public key.
3056 ret = emalloc(sizeof(struct cert_info));
3057 memset(ret, 0, sizeof(struct cert_info));
3058 if ((ret->pkey = X509_get_pubkey(cert)) == NULL) {
3059 msyslog(LOG_ERR, "cert_parse %s\n",
3060 ERR_error_string(ERR_get_error(), NULL));
3065 ret->version = X509_get_version(cert);
3066 X509_NAME_oneline(X509_get_subject_name(cert), pathbuf,
3068 ptr = strstr(pathbuf, "CN=");
3070 msyslog(LOG_INFO, "cert_parse: invalid subject %s",
3076 ret->subject = emalloc(strlen(ptr) + 1);
3077 strcpy(ret->subject, ptr + 3);
3080 * Extract remaining objects. Note that the NTP serial number is
3081 * the NTP seconds at the time of signing, but this might not be
3082 * the case for other authority. We don't bother to check the
3083 * objects at this time, since the real crunch can happen only
3084 * when the time is valid but not yet certificated.
3086 ret->nid = OBJ_obj2nid(cert->cert_info->signature->algorithm);
3087 ret->digest = (const EVP_MD *)EVP_get_digestbynid(ret->nid);
3089 (u_long)ASN1_INTEGER_get(X509_get_serialNumber(cert));
3090 X509_NAME_oneline(X509_get_issuer_name(cert), pathbuf,
3092 if ((ptr = strstr(pathbuf, "CN=")) == NULL) {
3093 msyslog(LOG_INFO, "cert_parse: invalid issuer %s",
3099 ret->issuer = emalloc(strlen(ptr) + 1);
3100 strcpy(ret->issuer, ptr + 3);
3101 ret->first = asn2ntp(X509_get_notBefore(cert));
3102 ret->last = asn2ntp(X509_get_notAfter(cert));
3105 * Extract extension fields. These are ad hoc ripoffs of
3106 * currently assigned functions and will certainly be changed
3107 * before prime time.
3109 cnt = X509_get_ext_count(cert);
3110 for (i = 0; i < cnt; i++) {
3111 ext = X509_get_ext(cert, i);
3112 method = X509V3_EXT_get(ext);
3113 temp = OBJ_obj2nid(ext->object);
3117 * If a key_usage field is present, we decode whether
3118 * this is a trusted or private certificate. This is
3119 * dorky; all we want is to compare NIDs, but OpenSSL
3120 * insists on BIO text strings.
3122 case NID_ext_key_usage:
3123 bp = BIO_new(BIO_s_mem());
3124 X509V3_EXT_print(bp, ext, 0, 0);
3125 BIO_gets(bp, pathbuf, MAXFILENAME);
3129 printf("cert_parse: %s: %s\n",
3130 OBJ_nid2ln(temp), pathbuf);
3132 if (strcmp(pathbuf, "Trust Root") == 0)
3133 ret->flags |= CERT_TRUST;
3134 else if (strcmp(pathbuf, "Private") == 0)
3135 ret->flags |= CERT_PRIV;
3139 * If a NID_subject_key_identifier field is present, it
3140 * contains the GQ public key.
3142 case NID_subject_key_identifier:
3143 ret->grplen = ext->value->length - 2;
3144 ret->grpkey = emalloc(ret->grplen);
3145 memcpy(ret->grpkey, &ext->value->data[2],
3152 * If certificate is self signed, verify signature.
3154 if (strcmp(ret->subject, ret->issuer) == 0) {
3155 if (!X509_verify(cert, ret->pkey)) {
3157 "cert_parse: signature not verified %s",
3166 * Verify certificate valid times. Note that certificates cannot
3169 if (ret->first > ret->last || ret->first < fstamp) {
3171 "cert_parse: invalid certificate %s first %u last %u fstamp %u",
3172 ret->subject, ret->first, ret->last, fstamp);
3179 * Build the value structure to sign and send later.
3181 ret->cert.fstamp = htonl(fstamp);
3182 ret->cert.vallen = htonl(len);
3183 ret->cert.ptr = emalloc(len);
3184 memcpy(ret->cert.ptr, asn1cert, len);
3187 X509_print_fp(stdout, cert);
3195 * cert_sign - sign x509 certificate equest and update value structure.
3197 * The certificate request includes a copy of the host certificate,
3198 * which includes the version number, subject name and public key of the
3199 * host. The resulting certificate includes these values plus the
3200 * serial number, issuer name and valid interval of the server. The
3201 * valid interval extends from the current time to the same time one
3202 * year hence. This may extend the life of the signed certificate beyond
3203 * that of the signer certificate.
3205 * It is convenient to use the NTP seconds of the current time as the
3206 * serial number. In the value structure the timestamp is the current
3207 * time and the filestamp is taken from the extension field. Note this
3208 * routine is called only when the client clock is synchronized to a
3209 * proventic source, so timestamp comparisons are valid.
3211 * The host certificate is valid from the time it was generated for a
3212 * period of one year. A signed certificate is valid from the time of
3213 * signature for a period of one year, but only the host certificate (or
3214 * sign certificate if used) is actually used to encrypt and decrypt
3215 * signatures. The signature trail is built from the client via the
3216 * intermediate servers to the trusted server. Each signature on the
3217 * trail must be valid at the time of signature, but it could happen
3218 * that a signer certificate expire before the signed certificate, which
3219 * remains valid until its expiration.
3223 * XEVNT_PUB bad or missing public key
3224 * XEVNT_CRT bad or missing certificate
3225 * XEVNT_VFY certificate not verified
3226 * XEVNT_PER host certificate expired
3230 struct exten *ep, /* extension field pointer */
3231 struct value *vp /* value pointer */
3234 X509 *req; /* X509 certificate request */
3235 X509 *cert; /* X509 certificate */
3236 X509_EXTENSION *ext; /* certificate extension */
3237 ASN1_INTEGER *serial; /* serial number */
3238 X509_NAME *subj; /* distinguished (common) name */
3239 EVP_PKEY *pkey; /* public key */
3240 EVP_MD_CTX ctx; /* message digest context */
3241 tstamp_t tstamp; /* NTP timestamp */
3247 * Decode ASN.1 objects and construct certificate structure.
3248 * Make sure the system clock is synchronized to a proventic
3251 tstamp = crypto_time();
3255 if (tstamp < cinfo->first || tstamp > cinfo->last)
3258 ptr = (u_char *)ep->pkt;
3259 if ((req = d2i_X509(NULL, &ptr, ntohl(ep->vallen))) == NULL) {
3260 msyslog(LOG_ERR, "cert_sign %s\n",
3261 ERR_error_string(ERR_get_error(), NULL));
3265 * Extract public key and check for errors.
3267 if ((pkey = X509_get_pubkey(req)) == NULL) {
3268 msyslog(LOG_ERR, "cert_sign %s\n",
3269 ERR_error_string(ERR_get_error(), NULL));
3275 * Generate X509 certificate signed by this server. For this
3276 * purpose the issuer name is the server name. Also copy any
3277 * extensions that might be present.
3280 X509_set_version(cert, X509_get_version(req));
3281 serial = ASN1_INTEGER_new();
3282 ASN1_INTEGER_set(serial, tstamp);
3283 X509_set_serialNumber(cert, serial);
3284 X509_gmtime_adj(X509_get_notBefore(cert), 0L);
3285 X509_gmtime_adj(X509_get_notAfter(cert), YEAR);
3286 subj = X509_get_issuer_name(cert);
3287 X509_NAME_add_entry_by_txt(subj, "commonName", MBSTRING_ASC,
3288 (u_char *)sys_hostname, strlen(sys_hostname), -1, 0);
3289 subj = X509_get_subject_name(req);
3290 X509_set_subject_name(cert, subj);
3291 X509_set_pubkey(cert, pkey);
3292 ext = X509_get_ext(req, 0);
3293 temp = X509_get_ext_count(req);
3294 for (i = 0; i < temp; i++) {
3295 ext = X509_get_ext(req, i);
3296 X509_add_ext(cert, ext, -1);
3301 * Sign and verify the certificate.
3303 X509_sign(cert, sign_pkey, sign_digest);
3304 if (!X509_verify(cert, sign_pkey)) {
3305 printf("cert_sign\n%s\n",
3306 ERR_error_string(ERR_get_error(), NULL));
3310 len = i2d_X509(cert, NULL);
3313 * Build and sign the value structure. We have to sign it here,
3314 * since the response has to be returned right away. This is a
3317 memset(vp, 0, sizeof(struct value));
3318 vp->tstamp = htonl(tstamp);
3319 vp->fstamp = ep->fstamp;
3320 vp->vallen = htonl(len);
3321 vp->ptr = emalloc(len);
3323 i2d_X509(cert, &ptr);
3325 vp->sig = emalloc(sign_siglen);
3326 EVP_SignInit(&ctx, sign_digest);
3327 EVP_SignUpdate(&ctx, (u_char *)vp, 12);
3328 EVP_SignUpdate(&ctx, vp->ptr, len);
3329 if (EVP_SignFinal(&ctx, vp->sig, &len, sign_pkey))
3330 vp->siglen = htonl(len);
3333 X509_print_fp(stdout, cert);
3341 * cert_valid - verify certificate with given public key
3343 * This is pretty ugly, as the certificate has to be verified in the
3344 * OpenSSL X509 structure, not in the DER format in the info/value
3349 * XEVNT_VFY certificate not verified
3353 struct cert_info *cinf, /* certificate information structure */
3354 EVP_PKEY *pkey /* public key */
3357 X509 *cert; /* X509 certificate */
3360 if (cinf->flags & CERT_SIGN)
3363 ptr = (u_char *)cinf->cert.ptr;
3364 cert = d2i_X509(NULL, &ptr, ntohl(cinf->cert.vallen));
3365 if (cert == NULL || !X509_verify(cert, pkey))
3374 * cert - install certificate in certificate list
3376 * This routine encodes an extension field into a certificate info/value
3377 * structure. It searches the certificate list for duplicates and
3378 * expunges whichever is older. It then searches the list for other
3379 * certificates that might be verified by this latest one. Finally, it
3380 * inserts this certificate first on the list.
3384 * XEVNT_FSP bad or missing filestamp
3385 * XEVNT_CRT bad or missing certificate
3389 struct exten *ep, /* cert info/value */
3390 struct peer *peer /* peer structure */
3393 struct cert_info *cp, *xp, *yp, **zp;
3396 * Parse and validate the signed certificate. If valid,
3397 * construct the info/value structure; otherwise, scamper home.
3399 if ((cp = cert_parse((u_char *)ep->pkt, ntohl(ep->vallen),
3400 ntohl(ep->fstamp))) == NULL)
3404 * Scan certificate list looking for another certificate with
3405 * the same subject and issuer. If another is found with the
3406 * same or older filestamp, unlink it and return the goodies to
3407 * the heap. If another is found with a later filestamp, discard
3408 * the new one and leave the building.
3410 * Make a note to study this issue again. An earlier certificate
3411 * with a long lifetime might be overtaken by a later
3412 * certificate with a short lifetime, thus invalidating the
3413 * earlier signature. However, we gotta find a way to leak old
3414 * stuff from the cache, so we do it anyway.
3418 for (xp = cinfo; xp != NULL; xp = xp->link) {
3419 if (strcmp(cp->subject, xp->subject) == 0 &&
3420 strcmp(cp->issuer, xp->issuer) == 0) {
3421 if (ntohl(cp->cert.fstamp) <=
3422 ntohl(xp->cert.fstamp)) {
3437 * Scan the certificate list to see if Y is signed by X. This is
3438 * independent of order.
3440 for (yp = cinfo; yp != NULL; yp = yp->link) {
3441 for (xp = cinfo; xp != NULL; xp = xp->link) {
3444 * If the issuer of certificate Y matches the
3445 * subject of certificate X, verify the
3446 * signature of Y using the public key of X. If
3449 if (strcmp(yp->issuer, xp->subject) != 0 ||
3450 xp->flags & CERT_ERROR)
3453 if (cert_valid(yp, xp->pkey) != XEVNT_OK) {
3454 yp->flags |= CERT_ERROR;
3459 * The signature Y is valid only if it begins
3460 * during the lifetime of X; however, it is not
3461 * necessarily an error, since some other
3462 * certificate might sign Y.
3464 if (yp->first < xp->first || yp->first >
3468 yp->flags |= CERT_SIGN;
3471 * If X is trusted, then Y is trusted. Note that
3472 * we might stumble over a self-signed
3473 * certificate that is not trusted, at least
3474 * temporarily. This can happen when a dude
3475 * first comes up, but has not synchronized the
3476 * clock and had its certificate signed by its
3477 * server. In case of broken certificate trail,
3478 * this might result in a loop that could
3479 * persist until timeout.
3481 if (!(xp->flags & (CERT_TRUST | CERT_VALID)))
3484 yp->flags |= CERT_VALID;
3487 * If subject Y matches the server subject name,
3488 * then Y has completed the certificate trail.
3489 * Save the group key and light the valid bit.
3491 if (strcmp(yp->subject, peer->subject) != 0)
3494 if (yp->grpkey != NULL) {
3495 if (peer->grpkey != NULL)
3496 BN_free(peer->grpkey);
3497 peer->grpkey = BN_bin2bn(yp->grpkey,
3500 peer->crypto |= CRYPTO_FLAG_VALID;
3503 * If the server has an an identity scheme,
3504 * fetch the identity credentials. If not, the
3505 * identity is verified only by the trusted
3506 * certificate. The next signature will set the
3509 if (peer->crypto & (CRYPTO_FLAG_GQ |
3510 CRYPTO_FLAG_IFF | CRYPTO_FLAG_MV))
3513 peer->crypto |= CRYPTO_FLAG_VRFY;
3518 * That was awesome. Now update the timestamps and signatures.
3526 * cert_free - free certificate information structure
3530 struct cert_info *cinf /* certificate info/value structure */
3533 if (cinf->pkey != NULL)
3534 EVP_PKEY_free(cinf->pkey);
3535 if (cinf->subject != NULL)
3536 free(cinf->subject);
3537 if (cinf->issuer != NULL)
3539 if (cinf->grpkey != NULL)
3541 value_free(&cinf->cert);
3547 ***********************************************************************
3549 * The following routines are used only at initialization time *
3551 ***********************************************************************
3554 * crypto_key - load cryptographic parameters and keys from files
3556 * This routine loads a PEM-encoded public/private key pair and extracts
3557 * the filestamp from the file name.
3559 * Returns public key pointer if valid, NULL if not. Side effect updates
3560 * the filestamp if valid.
3564 char *cp, /* file name */
3565 tstamp_t *fstamp /* filestamp */
3568 FILE *str; /* file handle */
3569 EVP_PKEY *pkey = NULL; /* public/private key */
3570 char filename[MAXFILENAME]; /* name of key file */
3571 char linkname[MAXFILENAME]; /* filestamp buffer) */
3572 char statstr[NTP_MAXSTRLEN]; /* statistics for filegen */
3576 * Open the key file. If the first character of the file name is
3577 * not '/', prepend the keys directory string. If something goes
3578 * wrong, abandon ship.
3581 strcpy(filename, cp);
3583 snprintf(filename, MAXFILENAME, "%s/%s", keysdir, cp);
3584 str = fopen(filename, "r");
3589 * Read the filestamp, which is contained in the first line.
3591 if ((ptr = fgets(linkname, MAXFILENAME, str)) == NULL) {
3592 msyslog(LOG_ERR, "crypto_key: no data %s\n",
3597 if ((ptr = strrchr(ptr, '.')) == NULL) {
3598 msyslog(LOG_ERR, "crypto_key: no filestamp %s\n",
3603 if (sscanf(++ptr, "%u", fstamp) != 1) {
3604 msyslog(LOG_ERR, "crypto_key: invalid timestamp %s\n",
3611 * Read and decrypt PEM-encoded private key.
3613 pkey = PEM_read_PrivateKey(str, NULL, NULL, passwd);
3616 msyslog(LOG_ERR, "crypto_key %s\n",
3617 ERR_error_string(ERR_get_error(), NULL));
3622 * Leave tracks in the cryptostats.
3624 if ((ptr = strrchr(linkname, '\n')) != NULL)
3626 snprintf(statstr, NTP_MAXSTRLEN, "%s mod %d", &linkname[2],
3627 EVP_PKEY_size(pkey) * 8);
3628 record_crypto_stats(NULL, statstr);
3631 printf("crypto_key: %s\n", statstr);
3633 if (pkey->type == EVP_PKEY_DSA)
3634 DSA_print_fp(stdout, pkey->pkey.dsa, 0);
3636 RSA_print_fp(stdout, pkey->pkey.rsa, 0);
3644 * crypto_cert - load certificate from file
3646 * This routine loads a X.509 RSA or DSA certificate from a file and
3647 * constructs a info/cert value structure for this machine. The
3648 * structure includes a filestamp extracted from the file name. Later
3649 * the certificate can be sent to another machine by request.
3651 * Returns certificate info/value pointer if valid, NULL if not.
3653 static struct cert_info * /* certificate information */
3655 char *cp /* file name */
3658 struct cert_info *ret; /* certificate information */
3659 FILE *str; /* file handle */
3660 char filename[MAXFILENAME]; /* name of certificate file */
3661 char linkname[MAXFILENAME]; /* filestamp buffer */
3662 char statstr[NTP_MAXSTRLEN]; /* statistics for filegen */
3663 tstamp_t fstamp; /* filestamp */
3666 char *name, *header;
3670 * Open the certificate file. If the first character of the file
3671 * name is not '/', prepend the keys directory string. If
3672 * something goes wrong, abandon ship.
3675 strcpy(filename, cp);
3677 snprintf(filename, MAXFILENAME, "%s/%s", keysdir, cp);
3678 str = fopen(filename, "r");
3683 * Read the filestamp, which is contained in the first line.
3685 if ((ptr = fgets(linkname, MAXFILENAME, str)) == NULL) {
3686 msyslog(LOG_ERR, "crypto_cert: no data %s\n",
3691 if ((ptr = strrchr(ptr, '.')) == NULL) {
3692 msyslog(LOG_ERR, "crypto_cert: no filestamp %s\n",
3697 if (sscanf(++ptr, "%u", &fstamp) != 1) {
3698 msyslog(LOG_ERR, "crypto_cert: invalid filestamp %s\n",
3705 * Read PEM-encoded certificate and install.
3707 if (!PEM_read(str, &name, &header, &data, &len)) {
3708 msyslog(LOG_ERR, "crypto_cert %s\n",
3709 ERR_error_string(ERR_get_error(), NULL));
3714 if (strcmp(name, "CERTIFICATE") !=0) {
3715 msyslog(LOG_INFO, "crypto_cert: wrong PEM type %s",
3725 * Parse certificate and generate info/value structure.
3727 ret = cert_parse(data, len, fstamp);
3733 if ((ptr = strrchr(linkname, '\n')) != NULL)
3735 snprintf(statstr, NTP_MAXSTRLEN,
3736 "%s 0x%x len %lu", &linkname[2], ret->flags, len);
3737 record_crypto_stats(NULL, statstr);
3740 printf("crypto_cert: %s\n", statstr);
3747 * crypto_tai - load leapseconds table from file
3749 * This routine loads the ERTS leapsecond file in NIST text format,
3750 * converts to a value structure and extracts a filestamp from the file
3751 * name. The data are used to establish the TAI offset from UTC, which
3752 * is provided to the kernel if supported. Later the data can be sent to
3753 * another machine on request.
3757 char *cp /* file name */
3760 FILE *str; /* file handle */
3761 char buf[NTP_MAXSTRLEN]; /* file line buffer */
3762 u_int32 leapsec[MAX_LEAP]; /* NTP time at leaps */
3763 int offset; /* offset at leap (s) */
3764 char filename[MAXFILENAME]; /* name of leapseconds file */
3765 char linkname[MAXFILENAME]; /* file link (for filestamp) */
3766 char statstr[NTP_MAXSTRLEN]; /* statistics for filegen */
3767 tstamp_t fstamp; /* filestamp */
3774 * Open the file and discard comment lines. If the first
3775 * character of the file name is not '/', prepend the keys
3776 * directory string. If the file is not found, not to worry; it
3777 * can be retrieved over the net. But, if it is found with
3778 * errors, we crash and burn.
3781 strcpy(filename, cp);
3783 snprintf(filename, MAXFILENAME, "%s/%s", keysdir, cp);
3784 if ((str = fopen(filename, "r")) == NULL)
3788 * Extract filestamp if present.
3790 rval = readlink(filename, linkname, MAXFILENAME - 1);
3792 linkname[rval] = '\0';
3793 dp = strrchr(linkname, '.');
3795 dp = strrchr(filename, '.');
3798 sscanf(++dp, "%u", &fstamp);
3801 tai_leap.fstamp = htonl(fstamp);
3804 * We are rather paranoid here, since an intruder might cause a
3805 * coredump by infiltrating naughty values. Empty lines and
3806 * comments are ignored. Other lines must begin with two
3807 * integers followed by junk or comments. The first integer is
3808 * the NTP seconds of leap insertion, the second is the offset
3809 * of TAI relative to UTC after that insertion. The second word
3810 * must equal the initial insertion of ten seconds on 1 January
3811 * 1972 plus one second for each succeeding insertion.
3814 while (i < MAX_LEAP) {
3815 dp = fgets(buf, NTP_MAXSTRLEN - 1, str);
3819 if (strlen(buf) < 1)
3825 if (sscanf(buf, "%u %d", &leapsec[i], &offset) != 2)
3828 if (i != offset - TAI_1972)
3836 "crypto_tai: leapseconds file %s error %d", cp,
3842 * The extension field table entries consists of the NTP seconds
3843 * of leap insertion in network byte order.
3845 len = i * sizeof(u_int32);
3846 tai_leap.vallen = htonl(len);
3848 tai_leap.ptr = (u_char *)ptr;
3849 for (j = 0; j < i; j++)
3850 *ptr++ = htonl(leapsec[j]);
3851 crypto_flags |= CRYPTO_FLAG_TAI;
3852 snprintf(statstr, NTP_MAXSTRLEN, "%s fs %u leap %u len %u", cp, fstamp,
3854 record_crypto_stats(NULL, statstr);
3857 printf("crypto_tai: %s\n", statstr);
3863 * crypto_setup - load keys, certificate and leapseconds table
3865 * This routine loads the public/private host key and certificate. If
3866 * available, it loads the public/private sign key, which defaults to
3867 * the host key, and leapseconds table. The host key must be RSA, but
3868 * the sign key can be either RSA or DSA. In either case, the public key
3869 * on the certificate must agree with the sign key.
3874 EVP_PKEY *pkey; /* private/public key pair */
3875 char filename[MAXFILENAME]; /* file name buffer */
3876 l_fp seed; /* crypto PRNG seed as NTP timestamp */
3877 tstamp_t fstamp; /* filestamp */
3878 tstamp_t sstamp; /* sign filestamp */
3883 * Initialize structures.
3888 gethostname(filename, MAXFILENAME);
3889 bytes = strlen(filename) + 1;
3890 sys_hostname = emalloc(bytes);
3891 memcpy(sys_hostname, filename, bytes);
3893 passwd = sys_hostname;
3894 memset(&hostval, 0, sizeof(hostval));
3895 memset(&pubkey, 0, sizeof(pubkey));
3896 memset(&tai_leap, 0, sizeof(tai_leap));
3899 * Load required random seed file and seed the random number
3900 * generator. Be default, it is found in the user home
3901 * directory. The root home directory may be / or /root,
3902 * depending on the system. Wiggle the contents a bit and write
3903 * it back so the sequence does not repeat when we next restart.
3905 ERR_load_crypto_strings();
3906 if (rand_file == NULL) {
3907 if ((RAND_file_name(filename, MAXFILENAME)) != NULL) {
3908 rand_file = emalloc(strlen(filename) + 1);
3909 strcpy(rand_file, filename);
3911 } else if (*rand_file != '/') {
3912 snprintf(filename, MAXFILENAME, "%s/%s", keysdir,
3915 rand_file = emalloc(strlen(filename) + 1);
3916 strcpy(rand_file, filename);
3918 if (rand_file == NULL) {
3920 "crypto_setup: random seed file not specified");
3923 if ((bytes = RAND_load_file(rand_file, -1)) == 0) {
3925 "crypto_setup: random seed file %s not found\n",
3929 arc4random_buf(&seed, sizeof(l_fp));
3930 RAND_seed(&seed, sizeof(l_fp));
3931 RAND_write_file(rand_file);
3932 OpenSSL_add_all_algorithms();
3936 "crypto_setup: OpenSSL version %lx random seed file %s bytes read %d\n",
3937 SSLeay(), rand_file, bytes);
3941 * Load required host key from file "ntpkey_host_<hostname>". It
3942 * also becomes the default sign key.
3944 if (host_file == NULL) {
3945 snprintf(filename, MAXFILENAME, "ntpkey_host_%s",
3947 host_file = emalloc(strlen(filename) + 1);
3948 strcpy(host_file, filename);
3950 pkey = crypto_key(host_file, &fstamp);
3953 "crypto_setup: host key file %s not found or corrupt",
3960 hostval.fstamp = htonl(fstamp);
3961 if (host_pkey->type != EVP_PKEY_RSA) {
3963 "crypto_setup: host key is not RSA key type");
3966 hostval.vallen = htonl(strlen(sys_hostname));
3967 hostval.ptr = (u_char *)sys_hostname;
3970 * Construct public key extension field for agreement scheme.
3972 len = i2d_PublicKey(host_pkey, NULL);
3975 i2d_PublicKey(host_pkey, &ptr);
3976 pubkey.vallen = htonl(len);
3977 pubkey.fstamp = hostval.fstamp;
3980 * Load optional sign key from file "ntpkey_sign_<hostname>". If
3981 * loaded, it becomes the sign key.
3983 if (sign_file == NULL) {
3984 snprintf(filename, MAXFILENAME, "ntpkey_sign_%s",
3986 sign_file = emalloc(strlen(filename) + 1);
3987 strcpy(sign_file, filename);
3989 pkey = crypto_key(sign_file, &fstamp);
3994 sign_siglen = EVP_PKEY_size(sign_pkey);
3997 * Load optional IFF parameters from file
3998 * "ntpkey_iff_<hostname>".
4000 if (iffpar_file == NULL) {
4001 snprintf(filename, MAXFILENAME, "ntpkey_iff_%s",
4003 iffpar_file = emalloc(strlen(filename) + 1);
4004 strcpy(iffpar_file, filename);
4006 iffpar_pkey = crypto_key(iffpar_file, &if_fstamp);
4007 if (iffpar_pkey != NULL)
4008 crypto_flags |= CRYPTO_FLAG_IFF;
4011 * Load optional GQ parameters from file "ntpkey_gq_<hostname>".
4013 if (gqpar_file == NULL) {
4014 snprintf(filename, MAXFILENAME, "ntpkey_gq_%s",
4016 gqpar_file = emalloc(strlen(filename) + 1);
4017 strcpy(gqpar_file, filename);
4019 gqpar_pkey = crypto_key(gqpar_file, &gq_fstamp);
4020 if (gqpar_pkey != NULL)
4021 crypto_flags |= CRYPTO_FLAG_GQ;
4024 * Load optional MV parameters from file "ntpkey_mv_<hostname>".
4026 if (mvpar_file == NULL) {
4027 snprintf(filename, MAXFILENAME, "ntpkey_mv_%s",
4029 mvpar_file = emalloc(strlen(filename) + 1);
4030 strcpy(mvpar_file, filename);
4032 mvpar_pkey = crypto_key(mvpar_file, &mv_fstamp);
4033 if (mvpar_pkey != NULL)
4034 crypto_flags |= CRYPTO_FLAG_MV;
4037 * Load required certificate from file "ntpkey_cert_<hostname>".
4039 if (cert_file == NULL) {
4040 snprintf(filename, MAXFILENAME, "ntpkey_cert_%s",
4042 cert_file = emalloc(strlen(filename) + 1);
4043 strcpy(cert_file, filename);
4045 if ((cinfo = crypto_cert(cert_file)) == NULL) {
4047 "certificate file %s not found or corrupt",
4053 * The subject name must be the same as the host name, unless
4054 * the certificate is private, in which case it may have come
4055 * from another host.
4057 if (!(cinfo->flags & CERT_PRIV) && strcmp(cinfo->subject,
4058 sys_hostname) != 0) {
4060 "crypto_setup: certificate %s not for this host",
4067 * It the certificate is trusted, the subject must be the same
4068 * as the issuer, in other words it must be self signed.
4070 if (cinfo->flags & CERT_TRUST && strcmp(cinfo->subject,
4071 cinfo->issuer) != 0) {
4072 if (cert_valid(cinfo, sign_pkey) != XEVNT_OK) {
4074 "crypto_setup: certificate %s is trusted, but not self signed.",
4080 sign_digest = cinfo->digest;
4081 if (cinfo->flags & CERT_PRIV)
4082 crypto_flags |= CRYPTO_FLAG_PRIV;
4083 crypto_flags |= cinfo->nid << 16;
4086 * Load optional leapseconds table from file "ntpkey_leap". If
4087 * the file is missing or defective, the values can later be
4088 * retrieved from a server.
4090 if (leap_file == NULL)
4091 leap_file = "ntpkey_leap";
4092 crypto_tai(leap_file);
4096 "crypto_setup: flags 0x%x host %s signature %s\n",
4097 crypto_flags, sys_hostname, OBJ_nid2ln(cinfo->nid));
4103 * crypto_config - configure data from crypto configuration command.
4107 int item, /* configuration item */
4108 char *cp /* file name */
4114 * Set random seed file name.
4116 case CRYPTO_CONF_RAND:
4117 rand_file = emalloc(strlen(cp) + 1);
4118 strcpy(rand_file, cp);
4122 * Set private key password.
4124 case CRYPTO_CONF_PW:
4125 passwd = emalloc(strlen(cp) + 1);
4130 * Set host file name.
4132 case CRYPTO_CONF_PRIV:
4133 host_file = emalloc(strlen(cp) + 1);
4134 strcpy(host_file, cp);
4138 * Set sign key file name.
4140 case CRYPTO_CONF_SIGN:
4141 sign_file = emalloc(strlen(cp) + 1);
4142 strcpy(sign_file, cp);
4146 * Set iff parameters file name.
4148 case CRYPTO_CONF_IFFPAR:
4149 iffpar_file = emalloc(strlen(cp) + 1);
4150 strcpy(iffpar_file, cp);
4154 * Set gq parameters file name.
4156 case CRYPTO_CONF_GQPAR:
4157 gqpar_file = emalloc(strlen(cp) + 1);
4158 strcpy(gqpar_file, cp);
4162 * Set mv parameters file name.
4164 case CRYPTO_CONF_MVPAR:
4165 mvpar_file = emalloc(strlen(cp) + 1);
4166 strcpy(mvpar_file, cp);
4170 * Set identity scheme.
4172 case CRYPTO_CONF_IDENT:
4173 if (!strcasecmp(cp, "iff"))
4174 ident_scheme |= CRYPTO_FLAG_IFF;
4175 else if (!strcasecmp(cp, "gq"))
4176 ident_scheme |= CRYPTO_FLAG_GQ;
4177 else if (!strcasecmp(cp, "mv"))
4178 ident_scheme |= CRYPTO_FLAG_MV;
4182 * Set certificate file name.
4184 case CRYPTO_CONF_CERT:
4185 cert_file = emalloc(strlen(cp) + 1);
4186 strcpy(cert_file, cp);
4190 * Set leapseconds file name.
4192 case CRYPTO_CONF_LEAP:
4193 leap_file = emalloc(strlen(cp) + 1);
4194 strcpy(leap_file, cp);
4197 crypto_flags |= CRYPTO_FLAG_ENAB;
4200 int ntp_crypto_bs_pubkey;
4201 # endif /* OPENSSL */