/contrib/ntp/ntpd/ntp_crypto.c
C | 4189 lines | 2414 code | 326 blank | 1449 comment | 577 complexity | 24628f797239e75d9f4988848ef9a38c MD5 | raw file
Possible License(s): MPL-2.0-no-copyleft-exception, BSD-3-Clause, LGPL-2.0, LGPL-2.1, BSD-2-Clause, 0BSD, JSON, AGPL-1.0, GPL-2.0
- /*
- * ntp_crypto.c - NTP version 4 public key routines
- */
- #ifdef HAVE_CONFIG_H
- #include <config.h>
- #endif
- #ifdef OPENSSL
- #include <stdio.h>
- #include <sys/types.h>
- #include <sys/param.h>
- #include <unistd.h>
- #include <fcntl.h>
- #include "ntpd.h"
- #include "ntp_stdlib.h"
- #include "ntp_unixtime.h"
- #include "ntp_string.h"
- #include <ntp_random.h>
- #include "openssl/asn1_mac.h"
- #include "openssl/bn.h"
- #include "openssl/err.h"
- #include "openssl/evp.h"
- #include "openssl/pem.h"
- #include "openssl/rand.h"
- #include "openssl/x509v3.h"
- #ifdef KERNEL_PLL
- #include "ntp_syscall.h"
- #endif /* KERNEL_PLL */
- /*
- * Extension field message format
- *
- * These are always signed and saved before sending in network byte
- * order. They must be converted to and from host byte order for
- * processing.
- *
- * +-------+-------+
- * | op | len | <- extension pointer
- * +-------+-------+
- * | assocID |
- * +---------------+
- * | timestamp | <- value pointer
- * +---------------+
- * | filestamp |
- * +---------------+
- * | value len |
- * +---------------+
- * | |
- * = value =
- * | |
- * +---------------+
- * | signature len |
- * +---------------+
- * | |
- * = signature =
- * | |
- * +---------------+
- *
- * The CRYPTO_RESP bit is set to 0 for requests, 1 for responses.
- * Requests carry the association ID of the receiver; responses carry
- * the association ID of the sender. Some messages include only the
- * operation/length and association ID words and so have length 8
- * octets. Ohers include the value structure and associated value and
- * signature fields. These messages include the timestamp, filestamp,
- * value and signature words and so have length at least 24 octets. The
- * signature and/or value fields can be empty, in which case the
- * respective length words are zero. An empty value with nonempty
- * signature is syntactically valid, but semantically questionable.
- *
- * The filestamp represents the time when a cryptographic data file such
- * as a public/private key pair is created. It follows every reference
- * depending on that file and serves as a means to obsolete earlier data
- * of the same type. The timestamp represents the time when the
- * cryptographic data of the message were last signed. Creation of a
- * cryptographic data file or signing a message can occur only when the
- * creator or signor is synchronized to an authoritative source and
- * proventicated to a trusted authority.
- *
- * Note there are four conditions required for server trust. First, the
- * public key on the certificate must be verified, which involves a
- * number of format, content and consistency checks. Next, the server
- * identity must be confirmed by one of four schemes: private
- * certificate, IFF scheme, GQ scheme or certificate trail hike to a
- * self signed trusted certificate. Finally, the server signature must
- * be verified.
- */
- /*
- * Cryptodefines
- */
- #define TAI_1972 10 /* initial TAI offset (s) */
- #define MAX_LEAP 100 /* max UTC leapseconds (s) */
- #define VALUE_LEN (6 * 4) /* min response field length */
- #define YEAR (60 * 60 * 24 * 365) /* seconds in year */
- /*
- * Global cryptodata in host byte order
- */
- u_int32 crypto_flags = 0x0; /* status word */
- /*
- * Global cryptodata in network byte order
- */
- struct cert_info *cinfo = NULL; /* certificate info/value */
- struct value hostval; /* host value */
- struct value pubkey; /* public key */
- struct value tai_leap; /* leapseconds table */
- EVP_PKEY *iffpar_pkey = NULL; /* IFF parameters */
- EVP_PKEY *gqpar_pkey = NULL; /* GQ parameters */
- EVP_PKEY *mvpar_pkey = NULL; /* MV parameters */
- char *iffpar_file = NULL; /* IFF parameters file */
- char *gqpar_file = NULL; /* GQ parameters file */
- char *mvpar_file = NULL; /* MV parameters file */
- /*
- * Private cryptodata in host byte order
- */
- static char *passwd = NULL; /* private key password */
- static EVP_PKEY *host_pkey = NULL; /* host key */
- static EVP_PKEY *sign_pkey = NULL; /* sign key */
- static const EVP_MD *sign_digest = NULL; /* sign digest */
- static u_int sign_siglen; /* sign key length */
- static char *rand_file = NULL; /* random seed file */
- static char *host_file = NULL; /* host key file */
- static char *sign_file = NULL; /* sign key file */
- static char *cert_file = NULL; /* certificate file */
- static char *leap_file = NULL; /* leapseconds file */
- static tstamp_t if_fstamp = 0; /* IFF filestamp */
- static tstamp_t gq_fstamp = 0; /* GQ file stamp */
- static tstamp_t mv_fstamp = 0; /* MV filestamp */
- static u_int ident_scheme = 0; /* server identity scheme */
- /*
- * Cryptotypes
- */
- static int crypto_verify P((struct exten *, struct value *,
- struct peer *));
- static int crypto_encrypt P((struct exten *, struct value *,
- keyid_t *));
- static int crypto_alice P((struct peer *, struct value *));
- static int crypto_alice2 P((struct peer *, struct value *));
- static int crypto_alice3 P((struct peer *, struct value *));
- static int crypto_bob P((struct exten *, struct value *));
- static int crypto_bob2 P((struct exten *, struct value *));
- static int crypto_bob3 P((struct exten *, struct value *));
- static int crypto_iff P((struct exten *, struct peer *));
- static int crypto_gq P((struct exten *, struct peer *));
- static int crypto_mv P((struct exten *, struct peer *));
- static u_int crypto_send P((struct exten *, struct value *));
- static tstamp_t crypto_time P((void));
- static u_long asn2ntp P((ASN1_TIME *));
- static struct cert_info *cert_parse P((u_char *, u_int, tstamp_t));
- static int cert_sign P((struct exten *, struct value *));
- static int cert_valid P((struct cert_info *, EVP_PKEY *));
- static int cert_install P((struct exten *, struct peer *));
- static void cert_free P((struct cert_info *));
- static EVP_PKEY *crypto_key P((char *, tstamp_t *));
- static int bighash P((BIGNUM *, BIGNUM *));
- static struct cert_info *crypto_cert P((char *));
- static void crypto_tai P((char *));
- #ifdef SYS_WINNT
- int
- readlink(char * link, char * file, int len) {
- return (-1);
- }
- #endif
- /*
- * session_key - generate session key
- *
- * This routine generates a session key from the source address,
- * destination address, key ID and private value. The value of the
- * session key is the MD5 hash of these values, while the next key ID is
- * the first four octets of the hash.
- *
- * Returns the next key ID
- */
- keyid_t
- session_key(
- struct sockaddr_storage *srcadr, /* source address */
- struct sockaddr_storage *dstadr, /* destination address */
- keyid_t keyno, /* key ID */
- keyid_t private, /* private value */
- u_long lifetime /* key lifetime */
- )
- {
- EVP_MD_CTX ctx; /* message digest context */
- u_char dgst[EVP_MAX_MD_SIZE]; /* message digest */
- keyid_t keyid; /* key identifer */
- u_int32 header[10]; /* data in network byte order */
- u_int hdlen, len;
- if (!dstadr)
- return 0;
-
- /*
- * Generate the session key and key ID. If the lifetime is
- * greater than zero, install the key and call it trusted.
- */
- hdlen = 0;
- switch(srcadr->ss_family) {
- case AF_INET:
- header[0] = ((struct sockaddr_in *)srcadr)->sin_addr.s_addr;
- header[1] = ((struct sockaddr_in *)dstadr)->sin_addr.s_addr;
- header[2] = htonl(keyno);
- header[3] = htonl(private);
- hdlen = 4 * sizeof(u_int32);
- break;
- case AF_INET6:
- memcpy(&header[0], &GET_INADDR6(*srcadr),
- sizeof(struct in6_addr));
- memcpy(&header[4], &GET_INADDR6(*dstadr),
- sizeof(struct in6_addr));
- header[8] = htonl(keyno);
- header[9] = htonl(private);
- hdlen = 10 * sizeof(u_int32);
- break;
- }
- EVP_DigestInit(&ctx, EVP_md5());
- EVP_DigestUpdate(&ctx, (u_char *)header, hdlen);
- EVP_DigestFinal(&ctx, dgst, &len);
- memcpy(&keyid, dgst, 4);
- keyid = ntohl(keyid);
- if (lifetime != 0) {
- MD5auth_setkey(keyno, dgst, len);
- authtrust(keyno, lifetime);
- }
- #ifdef DEBUG
- if (debug > 1)
- printf(
- "session_key: %s > %s %08x %08x hash %08x life %lu\n",
- stoa(srcadr), stoa(dstadr), keyno,
- private, keyid, lifetime);
- #endif
- return (keyid);
- }
- /*
- * make_keylist - generate key list
- *
- * Returns
- * XEVNT_OK success
- * XEVNT_PER host certificate expired
- *
- * This routine constructs a pseudo-random sequence by repeatedly
- * hashing the session key starting from a given source address,
- * destination address, private value and the next key ID of the
- * preceeding session key. The last entry on the list is saved along
- * with its sequence number and public signature.
- */
- int
- make_keylist(
- struct peer *peer, /* peer structure pointer */
- struct interface *dstadr /* interface */
- )
- {
- EVP_MD_CTX ctx; /* signature context */
- tstamp_t tstamp; /* NTP timestamp */
- struct autokey *ap; /* autokey pointer */
- struct value *vp; /* value pointer */
- keyid_t keyid = 0; /* next key ID */
- keyid_t cookie; /* private value */
- u_long lifetime;
- u_int len, mpoll;
- int i;
- if (!dstadr)
- return XEVNT_OK;
-
- /*
- * Allocate the key list if necessary.
- */
- tstamp = crypto_time();
- if (peer->keylist == NULL)
- peer->keylist = emalloc(sizeof(keyid_t) *
- NTP_MAXSESSION);
- /*
- * Generate an initial key ID which is unique and greater than
- * NTP_MAXKEY.
- */
- while (1) {
- keyid = (ntp_random() + NTP_MAXKEY + 1) & ((1 <<
- sizeof(keyid_t)) - 1);
- if (authhavekey(keyid))
- continue;
- break;
- }
- /*
- * Generate up to NTP_MAXSESSION session keys. Stop if the
- * next one would not be unique or not a session key ID or if
- * it would expire before the next poll. The private value
- * included in the hash is zero if broadcast mode, the peer
- * cookie if client mode or the host cookie if symmetric modes.
- */
- mpoll = 1 << min(peer->ppoll, peer->hpoll);
- lifetime = min(sys_automax, NTP_MAXSESSION * mpoll);
- if (peer->hmode == MODE_BROADCAST)
- cookie = 0;
- else
- cookie = peer->pcookie;
- for (i = 0; i < NTP_MAXSESSION; i++) {
- peer->keylist[i] = keyid;
- peer->keynumber = i;
- keyid = session_key(&dstadr->sin, &peer->srcadr, keyid,
- cookie, lifetime);
- lifetime -= mpoll;
- if (auth_havekey(keyid) || keyid <= NTP_MAXKEY ||
- lifetime <= mpoll)
- break;
- }
- /*
- * Save the last session key ID, sequence number and timestamp,
- * then sign these values for later retrieval by the clients. Be
- * careful not to use invalid key media. Use the public values
- * timestamp as filestamp.
- */
- vp = &peer->sndval;
- if (vp->ptr == NULL)
- vp->ptr = emalloc(sizeof(struct autokey));
- ap = (struct autokey *)vp->ptr;
- ap->seq = htonl(peer->keynumber);
- ap->key = htonl(keyid);
- vp->tstamp = htonl(tstamp);
- vp->fstamp = hostval.tstamp;
- vp->vallen = htonl(sizeof(struct autokey));
- vp->siglen = 0;
- if (tstamp != 0) {
- if (tstamp < cinfo->first || tstamp > cinfo->last)
- return (XEVNT_PER);
- if (vp->sig == NULL)
- vp->sig = emalloc(sign_siglen);
- EVP_SignInit(&ctx, sign_digest);
- EVP_SignUpdate(&ctx, (u_char *)vp, 12);
- EVP_SignUpdate(&ctx, vp->ptr, sizeof(struct autokey));
- if (EVP_SignFinal(&ctx, vp->sig, &len, sign_pkey))
- vp->siglen = htonl(len);
- else
- msyslog(LOG_ERR, "make_keys %s\n",
- ERR_error_string(ERR_get_error(), NULL));
- peer->flags |= FLAG_ASSOC;
- }
- #ifdef DEBUG
- if (debug)
- printf("make_keys: %d %08x %08x ts %u fs %u poll %d\n",
- ntohl(ap->seq), ntohl(ap->key), cookie,
- ntohl(vp->tstamp), ntohl(vp->fstamp), peer->hpoll);
- #endif
- return (XEVNT_OK);
- }
- /*
- * crypto_recv - parse extension fields
- *
- * This routine is called when the packet has been matched to an
- * association and passed sanity, format and MAC checks. We believe the
- * extension field values only if the field has proper format and
- * length, the timestamp and filestamp are valid and the signature has
- * valid length and is verified. There are a few cases where some values
- * are believed even if the signature fails, but only if the proventic
- * bit is not set.
- */
- int
- crypto_recv(
- struct peer *peer, /* peer structure pointer */
- struct recvbuf *rbufp /* packet buffer pointer */
- )
- {
- const EVP_MD *dp; /* message digest algorithm */
- u_int32 *pkt; /* receive packet pointer */
- struct autokey *ap, *bp; /* autokey pointer */
- struct exten *ep, *fp; /* extension pointers */
- int has_mac; /* length of MAC field */
- int authlen; /* offset of MAC field */
- associd_t associd; /* association ID */
- tstamp_t tstamp = 0; /* timestamp */
- tstamp_t fstamp = 0; /* filestamp */
- u_int len; /* extension field length */
- u_int code; /* extension field opcode */
- u_int vallen = 0; /* value length */
- X509 *cert; /* X509 certificate */
- char statstr[NTP_MAXSTRLEN]; /* statistics for filegen */
- keyid_t cookie; /* crumbles */
- int hismode; /* packet mode */
- int rval = XEVNT_OK;
- u_char *ptr;
- u_int32 temp32;
- /*
- * Initialize. Note that the packet has already been checked for
- * valid format and extension field lengths. First extract the
- * field length, command code and association ID in host byte
- * order. These are used with all commands and modes. Then check
- * the version number, which must be 2, and length, which must
- * be at least 8 for requests and VALUE_LEN (24) for responses.
- * Packets that fail either test sink without a trace. The
- * association ID is saved only if nonzero.
- */
- authlen = LEN_PKT_NOMAC;
- hismode = (int)PKT_MODE((&rbufp->recv_pkt)->li_vn_mode);
- while ((has_mac = rbufp->recv_length - authlen) > MAX_MAC_LEN) {
- pkt = (u_int32 *)&rbufp->recv_pkt + authlen / 4;
- ep = (struct exten *)pkt;
- code = ntohl(ep->opcode) & 0xffff0000;
- len = ntohl(ep->opcode) & 0x0000ffff;
- associd = (associd_t) ntohl(pkt[1]);
- rval = XEVNT_OK;
- #ifdef DEBUG
- if (debug)
- printf(
- "crypto_recv: flags 0x%x ext offset %d len %u code 0x%x assocID %d\n",
- peer->crypto, authlen, len, code >> 16,
- associd);
- #endif
- /*
- * Check version number and field length. If bad,
- * quietly ignore the packet.
- */
- if (((code >> 24) & 0x3f) != CRYPTO_VN || len < 8) {
- sys_unknownversion++;
- code |= CRYPTO_ERROR;
- }
- /*
- * Little vulnerability bandage here. If a perp tosses a
- * fake association ID over the fence, we better toss it
- * out. Only the first one counts.
- */
- if (code & CRYPTO_RESP) {
- if (peer->assoc == 0)
- peer->assoc = associd;
- else if (peer->assoc != associd)
- code |= CRYPTO_ERROR;
- }
- if (len >= VALUE_LEN) {
- tstamp = ntohl(ep->tstamp);
- fstamp = ntohl(ep->fstamp);
- vallen = ntohl(ep->vallen);
- }
- switch (code) {
- /*
- * Install status word, host name, signature scheme and
- * association ID. In OpenSSL the signature algorithm is
- * bound to the digest algorithm, so the NID completely
- * defines the signature scheme. Note the request and
- * response are identical, but neither is validated by
- * signature. The request is processed here only in
- * symmetric modes. The server name field might be
- * useful to implement access controls in future.
- */
- case CRYPTO_ASSOC:
- /*
- * If the machine is running when this message
- * arrives, the other fellow has reset and so
- * must we. Otherwise, pass the extension field
- * to the transmit side.
- */
- if (peer->crypto) {
- rval = XEVNT_ERR;
- break;
- }
- fp = emalloc(len);
- memcpy(fp, ep, len);
- temp32 = CRYPTO_RESP;
- fp->opcode |= htonl(temp32);
- peer->cmmd = fp;
- /* fall through */
- case CRYPTO_ASSOC | CRYPTO_RESP:
- /*
- * Discard the message if it has already been
- * stored or the message has been amputated.
- */
- if (peer->crypto)
- break;
- if (vallen == 0 || vallen > MAXHOSTNAME ||
- len < VALUE_LEN + vallen) {
- rval = XEVNT_LEN;
- break;
- }
- /*
- * Check the identity schemes are compatible. If
- * the client has PC, the server must have PC,
- * in which case the server public key and
- * identity are presumed valid, so we skip the
- * certificate and identity exchanges and move
- * immediately to the cookie exchange which
- * confirms the server signature.
- */
- #ifdef DEBUG
- if (debug)
- printf(
- "crypto_recv: ident host 0x%x server 0x%x\n",
- crypto_flags, fstamp);
- #endif
- temp32 = (crypto_flags | ident_scheme) &
- fstamp & CRYPTO_FLAG_MASK;
- if (crypto_flags & CRYPTO_FLAG_PRIV) {
- if (!(fstamp & CRYPTO_FLAG_PRIV)) {
- rval = XEVNT_KEY;
- break;
- } else {
- fstamp |= CRYPTO_FLAG_VALID |
- CRYPTO_FLAG_VRFY |
- CRYPTO_FLAG_SIGN;
- }
- /*
- * In symmetric modes it is an error if either
- * peer requests identity and the other peer
- * does not support it.
- */
- } else if ((hismode == MODE_ACTIVE || hismode ==
- MODE_PASSIVE) && ((crypto_flags | fstamp) &
- CRYPTO_FLAG_MASK) && !temp32) {
- rval = XEVNT_KEY;
- break;
- /*
- * It is an error if the client requests
- * identity and the server does not support it.
- */
- } else if (hismode == MODE_CLIENT && (fstamp &
- CRYPTO_FLAG_MASK) && !temp32) {
- rval = XEVNT_KEY;
- break;
- }
- /*
- * Otherwise, the identity scheme(s) are those
- * that both client and server support.
- */
- fstamp = temp32 | (fstamp & ~CRYPTO_FLAG_MASK);
- /*
- * Discard the message if the signature digest
- * NID is not supported.
- */
- temp32 = (fstamp >> 16) & 0xffff;
- dp =
- (const EVP_MD *)EVP_get_digestbynid(temp32);
- if (dp == NULL) {
- rval = XEVNT_MD;
- break;
- }
- /*
- * Save status word, host name and message
- * digest/signature type.
- */
- peer->crypto = fstamp;
- peer->digest = dp;
- peer->subject = emalloc(vallen + 1);
- memcpy(peer->subject, ep->pkt, vallen);
- peer->subject[vallen] = '\0';
- peer->issuer = emalloc(vallen + 1);
- strcpy(peer->issuer, peer->subject);
- temp32 = (fstamp >> 16) & 0xffff;
- snprintf(statstr, NTP_MAXSTRLEN,
- "flags 0x%x host %s signature %s", fstamp,
- peer->subject, OBJ_nid2ln(temp32));
- record_crypto_stats(&peer->srcadr, statstr);
- #ifdef DEBUG
- if (debug)
- printf("crypto_recv: %s\n", statstr);
- #endif
- break;
- /*
- * Decode X509 certificate in ASN.1 format and extract
- * the data containing, among other things, subject
- * name and public key. In the default identification
- * scheme, the certificate trail is followed to a self
- * signed trusted certificate.
- */
- case CRYPTO_CERT | CRYPTO_RESP:
- /*
- * Discard the message if invalid.
- */
- if ((rval = crypto_verify(ep, NULL, peer)) !=
- XEVNT_OK)
- break;
- /*
- * Scan the certificate list to delete old
- * versions and link the newest version first on
- * the list.
- */
- if ((rval = cert_install(ep, peer)) != XEVNT_OK)
- break;
- /*
- * If we snatch the certificate before the
- * server certificate has been signed by its
- * server, it will be self signed. When it is,
- * we chase the certificate issuer, which the
- * server has, and keep going until a self
- * signed trusted certificate is found. Be sure
- * to update the issuer field, since it may
- * change.
- */
- if (peer->issuer != NULL)
- free(peer->issuer);
- peer->issuer = emalloc(strlen(cinfo->issuer) +
- 1);
- strcpy(peer->issuer, cinfo->issuer);
- /*
- * We plug in the public key and lifetime from
- * the first certificate received. However, note
- * that this certificate might not be signed by
- * the server, so we can't check the
- * signature/digest NID.
- */
- if (peer->pkey == NULL) {
- ptr = (u_char *)cinfo->cert.ptr;
- cert = d2i_X509(NULL, &ptr,
- ntohl(cinfo->cert.vallen));
- peer->pkey = X509_get_pubkey(cert);
- X509_free(cert);
- }
- peer->flash &= ~TEST8;
- temp32 = cinfo->nid;
- snprintf(statstr, NTP_MAXSTRLEN,
- "cert %s 0x%x %s (%u) fs %u",
- cinfo->subject, cinfo->flags,
- OBJ_nid2ln(temp32), temp32,
- ntohl(ep->fstamp));
- record_crypto_stats(&peer->srcadr, statstr);
- #ifdef DEBUG
- if (debug)
- printf("crypto_recv: %s\n", statstr);
- #endif
- break;
- /*
- * Schnorr (IFF)identity scheme. This scheme is designed
- * for use with shared secret group keys and where the
- * certificate may be generated by a third party. The
- * client sends a challenge to the server, which
- * performs a calculation and returns the result. A
- * positive result is possible only if both client and
- * server contain the same secret group key.
- */
- case CRYPTO_IFF | CRYPTO_RESP:
- /*
- * Discard the message if invalid or certificate
- * trail not trusted.
- */
- if (!(peer->crypto & CRYPTO_FLAG_VALID)) {
- rval = XEVNT_ERR;
- break;
- }
- if ((rval = crypto_verify(ep, NULL, peer)) !=
- XEVNT_OK)
- break;
- /*
- * If the the challenge matches the response,
- * the certificate public key, as well as the
- * server public key, signatyre and identity are
- * all verified at the same time. The server is
- * declared trusted, so we skip further
- * certificate stages and move immediately to
- * the cookie stage.
- */
- if ((rval = crypto_iff(ep, peer)) != XEVNT_OK)
- break;
- peer->crypto |= CRYPTO_FLAG_VRFY |
- CRYPTO_FLAG_PROV;
- peer->flash &= ~TEST8;
- snprintf(statstr, NTP_MAXSTRLEN, "iff fs %u",
- ntohl(ep->fstamp));
- record_crypto_stats(&peer->srcadr, statstr);
- #ifdef DEBUG
- if (debug)
- printf("crypto_recv: %s\n", statstr);
- #endif
- break;
- /*
- * Guillou-Quisquater (GQ) identity scheme. This scheme
- * is designed for use with public certificates carrying
- * the GQ public key in an extension field. The client
- * sends a challenge to the server, which performs a
- * calculation and returns the result. A positive result
- * is possible only if both client and server contain
- * the same group key and the server has the matching GQ
- * private key.
- */
- case CRYPTO_GQ | CRYPTO_RESP:
- /*
- * Discard the message if invalid or certificate
- * trail not trusted.
- */
- if (!(peer->crypto & CRYPTO_FLAG_VALID)) {
- rval = XEVNT_ERR;
- break;
- }
- if ((rval = crypto_verify(ep, NULL, peer)) !=
- XEVNT_OK)
- break;
- /*
- * If the the challenge matches the response,
- * the certificate public key, as well as the
- * server public key, signatyre and identity are
- * all verified at the same time. The server is
- * declared trusted, so we skip further
- * certificate stages and move immediately to
- * the cookie stage.
- */
- if ((rval = crypto_gq(ep, peer)) != XEVNT_OK)
- break;
- peer->crypto |= CRYPTO_FLAG_VRFY |
- CRYPTO_FLAG_PROV;
- peer->flash &= ~TEST8;
- snprintf(statstr, NTP_MAXSTRLEN, "gq fs %u",
- ntohl(ep->fstamp));
- record_crypto_stats(&peer->srcadr, statstr);
- #ifdef DEBUG
- if (debug)
- printf("crypto_recv: %s\n", statstr);
- #endif
- break;
- /*
- * MV
- */
- case CRYPTO_MV | CRYPTO_RESP:
- /*
- * Discard the message if invalid or certificate
- * trail not trusted.
- */
- if (!(peer->crypto & CRYPTO_FLAG_VALID)) {
- rval = XEVNT_ERR;
- break;
- }
- if ((rval = crypto_verify(ep, NULL, peer)) !=
- XEVNT_OK)
- break;
- /*
- * If the the challenge matches the response,
- * the certificate public key, as well as the
- * server public key, signatyre and identity are
- * all verified at the same time. The server is
- * declared trusted, so we skip further
- * certificate stages and move immediately to
- * the cookie stage.
- */
- if ((rval = crypto_mv(ep, peer)) != XEVNT_OK)
- break;
- peer->crypto |= CRYPTO_FLAG_VRFY |
- CRYPTO_FLAG_PROV;
- peer->flash &= ~TEST8;
- snprintf(statstr, NTP_MAXSTRLEN, "mv fs %u",
- ntohl(ep->fstamp));
- record_crypto_stats(&peer->srcadr, statstr);
- #ifdef DEBUG
- if (debug)
- printf("crypto_recv: %s\n", statstr);
- #endif
- break;
- /*
- * Cookie request in symmetric modes. Roll a random
- * cookie and install in symmetric mode. Encrypt for the
- * response, which is transmitted later.
- */
- case CRYPTO_COOK:
- /*
- * Discard the message if invalid or certificate
- * trail not trusted.
- */
- if (!(peer->crypto & CRYPTO_FLAG_VALID)) {
- rval = XEVNT_ERR;
- break;
- }
- if ((rval = crypto_verify(ep, NULL, peer)) !=
- XEVNT_OK)
- break;
- /*
- * Pass the extension field to the transmit
- * side. If already agreed, walk away.
- */
- fp = emalloc(len);
- memcpy(fp, ep, len);
- temp32 = CRYPTO_RESP;
- fp->opcode |= htonl(temp32);
- peer->cmmd = fp;
- if (peer->crypto & CRYPTO_FLAG_AGREE) {
- peer->flash &= ~TEST8;
- break;
- }
- /*
- * Install cookie values and light the cookie
- * bit. The transmit side will pick up and
- * encrypt it for the response.
- */
- key_expire(peer);
- peer->cookval.tstamp = ep->tstamp;
- peer->cookval.fstamp = ep->fstamp;
- RAND_bytes((u_char *)&peer->pcookie, 4);
- peer->crypto &= ~CRYPTO_FLAG_AUTO;
- peer->crypto |= CRYPTO_FLAG_AGREE;
- peer->flash &= ~TEST8;
- snprintf(statstr, NTP_MAXSTRLEN, "cook %x ts %u fs %u",
- peer->pcookie, ntohl(ep->tstamp),
- ntohl(ep->fstamp));
- record_crypto_stats(&peer->srcadr, statstr);
- #ifdef DEBUG
- if (debug)
- printf("crypto_recv: %s\n", statstr);
- #endif
- break;
- /*
- * Cookie response in client and symmetric modes. If the
- * cookie bit is set, the working cookie is the EXOR of
- * the current and new values.
- */
- case CRYPTO_COOK | CRYPTO_RESP:
- /*
- * Discard the message if invalid or identity
- * not confirmed or signature not verified with
- * respect to the cookie values.
- */
- if (!(peer->crypto & CRYPTO_FLAG_VRFY)) {
- rval = XEVNT_ERR;
- break;
- }
- if ((rval = crypto_verify(ep, &peer->cookval,
- peer)) != XEVNT_OK)
- break;
- /*
- * Decrypt the cookie, hunting all the time for
- * errors.
- */
- if (vallen == (u_int) EVP_PKEY_size(host_pkey)) {
- RSA_private_decrypt(vallen,
- (u_char *)ep->pkt,
- (u_char *)&temp32,
- host_pkey->pkey.rsa,
- RSA_PKCS1_OAEP_PADDING);
- cookie = ntohl(temp32);
- } else {
- rval = XEVNT_CKY;
- break;
- }
- /*
- * Install cookie values and light the cookie
- * bit. If this is not broadcast client mode, we
- * are done here.
- */
- key_expire(peer);
- peer->cookval.tstamp = ep->tstamp;
- peer->cookval.fstamp = ep->fstamp;
- if (peer->crypto & CRYPTO_FLAG_AGREE)
- peer->pcookie ^= cookie;
- else
- peer->pcookie = cookie;
- if (peer->hmode == MODE_CLIENT &&
- !(peer->cast_flags & MDF_BCLNT))
- peer->crypto |= CRYPTO_FLAG_AUTO;
- else
- peer->crypto &= ~CRYPTO_FLAG_AUTO;
- peer->crypto |= CRYPTO_FLAG_AGREE;
- peer->flash &= ~TEST8;
- snprintf(statstr, NTP_MAXSTRLEN, "cook %x ts %u fs %u",
- peer->pcookie, ntohl(ep->tstamp),
- ntohl(ep->fstamp));
- record_crypto_stats(&peer->srcadr, statstr);
- #ifdef DEBUG
- if (debug)
- printf("crypto_recv: %s\n", statstr);
- #endif
- break;
- /*
- * Install autokey values in broadcast client and
- * symmetric modes. We have to do this every time the
- * sever/peer cookie changes or a new keylist is
- * rolled. Ordinarily, this is automatic as this message
- * is piggybacked on the first NTP packet sent upon
- * either of these events. Note that a broadcast client
- * or symmetric peer can receive this response without a
- * matching request.
- */
- case CRYPTO_AUTO | CRYPTO_RESP:
- /*
- * Discard the message if invalid or identity
- * not confirmed or signature not verified with
- * respect to the receive autokey values.
- */
- if (!(peer->crypto & CRYPTO_FLAG_VRFY)) {
- rval = XEVNT_ERR;
- break;
- }
- if ((rval = crypto_verify(ep, &peer->recval,
- peer)) != XEVNT_OK)
- break;
- /*
- * Install autokey values and light the
- * autokey bit. This is not hard.
- */
- if (peer->recval.ptr == NULL)
- peer->recval.ptr =
- emalloc(sizeof(struct autokey));
- bp = (struct autokey *)peer->recval.ptr;
- peer->recval.tstamp = ep->tstamp;
- peer->recval.fstamp = ep->fstamp;
- ap = (struct autokey *)ep->pkt;
- bp->seq = ntohl(ap->seq);
- bp->key = ntohl(ap->key);
- peer->pkeyid = bp->key;
- peer->crypto |= CRYPTO_FLAG_AUTO;
- peer->flash &= ~TEST8;
- snprintf(statstr, NTP_MAXSTRLEN,
- "auto seq %d key %x ts %u fs %u", bp->seq,
- bp->key, ntohl(ep->tstamp),
- ntohl(ep->fstamp));
- record_crypto_stats(&peer->srcadr, statstr);
- #ifdef DEBUG
- if (debug)
- printf("crypto_recv: %s\n", statstr);
- #endif
- break;
-
- /*
- * X509 certificate sign response. Validate the
- * certificate signed by the server and install. Later
- * this can be provided to clients of this server in
- * lieu of the self signed certificate in order to
- * validate the public key.
- */
- case CRYPTO_SIGN | CRYPTO_RESP:
- /*
- * Discard the message if invalid or not
- * proventic.
- */
- if (!(peer->crypto & CRYPTO_FLAG_PROV)) {
- rval = XEVNT_ERR;
- break;
- }
- if ((rval = crypto_verify(ep, NULL, peer)) !=
- XEVNT_OK)
- break;
- /*
- * Scan the certificate list to delete old
- * versions and link the newest version first on
- * the list.
- */
- if ((rval = cert_install(ep, peer)) != XEVNT_OK)
- break;
- peer->crypto |= CRYPTO_FLAG_SIGN;
- peer->flash &= ~TEST8;
- temp32 = cinfo->nid;
- snprintf(statstr, NTP_MAXSTRLEN,
- "sign %s 0x%x %s (%u) fs %u",
- cinfo->issuer, cinfo->flags,
- OBJ_nid2ln(temp32), temp32,
- ntohl(ep->fstamp));
- record_crypto_stats(&peer->srcadr, statstr);
- #ifdef DEBUG
- if (debug)
- printf("crypto_recv: %s\n", statstr);
- #endif
- break;
- /*
- * Install leapseconds table in symmetric modes. This
- * table is proventicated to the NIST primary servers,
- * either by copying the file containing the table from
- * a NIST server to a trusted server or directly using
- * this protocol. While the entire table is installed at
- * the server, presently only the current TAI offset is
- * provided via the kernel to other applications.
- */
- case CRYPTO_TAI:
- /*
- * Discard the message if invalid.
- */
- if ((rval = crypto_verify(ep, NULL, peer)) !=
- XEVNT_OK)
- break;
- /*
- * Pass the extension field to the transmit
- * side. Continue below if a leapseconds table
- * accompanies the message.
- */
- fp = emalloc(len);
- memcpy(fp, ep, len);
- temp32 = CRYPTO_RESP;
- fp->opcode |= htonl(temp32);
- peer->cmmd = fp;
- if (len <= VALUE_LEN) {
- peer->flash &= ~TEST8;
- break;
- }
- /* fall through */
- case CRYPTO_TAI | CRYPTO_RESP:
- /*
- * If this is a response, discard the message if
- * signature not verified with respect to the
- * leapsecond table values.
- */
- if (peer->cmmd == NULL) {
- if ((rval = crypto_verify(ep,
- &peer->tai_leap, peer)) != XEVNT_OK)
- break;
- }
- /*
- * Initialize peer variables with latest update.
- */
- peer->tai_leap.tstamp = ep->tstamp;
- peer->tai_leap.fstamp = ep->fstamp;
- peer->tai_leap.vallen = ep->vallen;
- /*
- * Install the new table if there is no stored
- * table or the new table is more recent than
- * the stored table. Since a filestamp may have
- * changed, recompute the signatures.
- */
- if (ntohl(peer->tai_leap.fstamp) >
- ntohl(tai_leap.fstamp)) {
- tai_leap.fstamp = ep->fstamp;
- tai_leap.vallen = ep->vallen;
- if (tai_leap.ptr != NULL)
- free(tai_leap.ptr);
- tai_leap.ptr = emalloc(vallen);
- memcpy(tai_leap.ptr, ep->pkt, vallen);
- crypto_update();
- }
- crypto_flags |= CRYPTO_FLAG_TAI;
- peer->crypto |= CRYPTO_FLAG_LEAP;
- peer->flash &= ~TEST8;
- snprintf(statstr, NTP_MAXSTRLEN,
- "leap %u ts %u fs %u", vallen,
- ntohl(ep->tstamp), ntohl(ep->fstamp));
- record_crypto_stats(&peer->srcadr, statstr);
- #ifdef DEBUG
- if (debug)
- printf("crypto_recv: %s\n", statstr);
- #endif
- break;
- /*
- * We come here in symmetric modes for miscellaneous
- * commands that have value fields but are processed on
- * the transmit side. All we need do here is check for
- * valid field length. Remaining checks are below and on
- * the transmit side.
- */
- case CRYPTO_CERT:
- case CRYPTO_IFF:
- case CRYPTO_GQ:
- case CRYPTO_MV:
- case CRYPTO_SIGN:
- if (len < VALUE_LEN) {
- rval = XEVNT_LEN;
- break;
- }
- /* fall through */
- /*
- * We come here for miscellaneous requests and unknown
- * requests and responses. If an unknown response or
- * error, forget it. If a request, save the extension
- * field for later. Unknown requests will be caught on
- * the transmit side.
- */
- default:
- if (code & (CRYPTO_RESP | CRYPTO_ERROR)) {
- rval = XEVNT_ERR;
- } else if ((rval = crypto_verify(ep, NULL,
- peer)) == XEVNT_OK) {
- fp = emalloc(len);
- memcpy(fp, ep, len);
- temp32 = CRYPTO_RESP;
- fp->opcode |= htonl(temp32);
- peer->cmmd = fp;
- }
- }
- /*
- * We don't log length/format/timestamp errors and
- * duplicates, which are log clogging vulnerabilities.
- * The first error found terminates the extension field
- * scan and we return the laundry to the caller. A
- * length/format/timestamp error on transmit is
- * cheerfully ignored, as the message is not sent.
- */
- if (rval > XEVNT_TSP) {
- snprintf(statstr, NTP_MAXSTRLEN,
- "error %x opcode %x ts %u fs %u", rval,
- code, tstamp, fstamp);
- record_crypto_stats(&peer->srcadr, statstr);
- report_event(rval, peer);
- #ifdef DEBUG
- if (debug)
- printf("crypto_recv: %s\n", statstr);
- #endif
- break;
- } else if (rval > XEVNT_OK && (code & CRYPTO_RESP)) {
- rval = XEVNT_OK;
- }
- authlen += len;
- }
- return (rval);
- }
- /*
- * crypto_xmit - construct extension fields
- *
- * This routine is called both when an association is configured and
- * when one is not. The only case where this matters is to retrieve the
- * autokey information, in which case the caller has to provide the
- * association ID to match the association.
- *
- * Returns length of extension field.
- */
- int
- crypto_xmit(
- struct pkt *xpkt, /* transmit packet pointer */
- struct sockaddr_storage *srcadr_sin, /* active runway */
- int start, /* offset to extension field */
- struct exten *ep, /* extension pointer */
- keyid_t cookie /* session cookie */
- )
- {
- u_int32 *pkt; /* packet pointer */
- struct peer *peer; /* peer structure pointer */
- u_int opcode; /* extension field opcode */
- struct exten *fp; /* extension pointers */
- struct cert_info *cp, *xp; /* certificate info/value pointer */
- char certname[MAXHOSTNAME + 1]; /* subject name buffer */
- char statstr[NTP_MAXSTRLEN]; /* statistics for filegen */
- tstamp_t tstamp;
- u_int vallen;
- u_int len;
- struct value vtemp;
- associd_t associd;
- int rval;
- keyid_t tcookie;
- /*
- * Generate the requested extension field request code, length
- * and association ID. If this is a response and the host is not
- * synchronized, light the error bit and go home.
- */
- pkt = (u_int32 *)xpkt + start / 4;
- fp = (struct exten *)pkt;
- opcode = ntohl(ep->opcode);
- associd = (associd_t) ntohl(ep->associd);
- fp->associd = htonl(associd);
- len = 8;
- rval = XEVNT_OK;
- tstamp = crypto_time();
- switch (opcode & 0xffff0000) {
- /*
- * Send association request and response with status word and
- * host name. Note, this message is not signed and the filestamp
- * contains only the status word.
- */
- case CRYPTO_ASSOC | CRYPTO_RESP:
- len += crypto_send(fp, &hostval);
- fp->fstamp = htonl(crypto_flags);
- break;
- case CRYPTO_ASSOC:
- len += crypto_send(fp, &hostval);
- fp->fstamp = htonl(crypto_flags | ident_scheme);
- break;
- /*
- * Send certificate request. Use the values from the extension
- * field.
- */
- case CRYPTO_CERT:
- memset(&vtemp, 0, sizeof(vtemp));
- vtemp.tstamp = ep->tstamp;
- vtemp.fstamp = ep->fstamp;
- vtemp.vallen = ep->vallen;
- vtemp.ptr = (u_char *)ep->pkt;
- len += crypto_send(fp, &vtemp);
- break;
- /*
- * Send certificate response or sign request. Use the values
- * from the certificate cache. If the request contains no
- * subject name, assume the name of this host. This is for
- * backwards compatibility. Private certificates are never sent.
- */
- case CRYPTO_SIGN:
- case CRYPTO_CERT | CRYPTO_RESP:
- vallen = ntohl(ep->vallen);
- if (vallen == 8) {
- strcpy(certname, sys_hostname);
- } else if (vallen == 0 || vallen > MAXHOSTNAME) {
- rval = XEVNT_LEN;
- break;
- } else {
- memcpy(certname, ep->pkt, vallen);
- certname[vallen] = '\0';
- }
- /*
- * Find all certificates with matching subject. If a
- * self-signed, trusted certificate is found, use that.
- * If not, use the first one with matching subject. A
- * private certificate is never divulged or signed.
- */
- xp = NULL;
- for (cp = cinfo; cp != NULL; cp = cp->link) {
- if (cp->flags & CERT_PRIV)
- continue;
- if (strcmp(certname, cp->subject) == 0) {
- if (xp == NULL)
- xp = cp;
- if (strcmp(certname, cp->issuer) ==
- 0 && cp->flags & CERT_TRUST) {
- xp = cp;
- break;
- }
- }
- }
- /*
- * Be careful who you trust. If not yet synchronized,
- * give back an empty response. If certificate not found
- * or beyond the lifetime, return an error. This is to
- * avoid a bad dude trying to get an expired certificate
- * re-signed. Otherwise, send it.
- *
- * Note the timestamp and filestamp are taken from the
- * certificate value structure. For all certificates the
- * timestamp is the latest signature update time. For
- * host and imported certificates the filestamp is the
- * creation epoch. For signed certificates the filestamp
- * is the creation epoch of the trusted certificate at
- * the base of the certificate trail. In principle, this
- * allows strong checking for signature masquerade.
- */
- if (tstamp == 0)
- break;
- if (xp == NULL)
- rval = XEVNT_CRT;
- else if (tstamp < xp->first || tstamp > xp->last)
- rval = XEVNT_SRV;
- else
- len += crypto_send(fp, &xp->cert);
- break;
- /*
- * Send challenge in Schnorr (IFF) identity scheme.
- */
- case CRYPTO_IFF:
- if ((peer = findpeerbyassoc(ep->pkt[0])) == NULL) {
- rval = XEVNT_ERR;
- break;
- }
- if ((rval = crypto_alice(peer, &vtemp)) == XEVNT_OK) {
- len += crypto_send(fp, &vtemp);
- value_free(&vtemp);
- }
- break;
- /*
- * Send response in Schnorr (IFF) identity scheme.
- */
- case CRYPTO_IFF | CRYPTO_RESP:
- if ((rval = crypto_bob(ep, &vtemp)) == XEVNT_OK) {
- len += crypto_send(fp, &vtemp);
- value_free(&vtemp);
- }
- break;
- /*
- * Send challenge in Guillou-Quisquater (GQ) identity scheme.
- */
- case CRYPTO_GQ:
- if ((peer = findpeerbyassoc(ep->pkt[0])) == NULL) {
- rval = XEVNT_ERR;
- break;
- }
- if ((rval = crypto_alice2(peer, &vtemp)) == XEVNT_OK) {
- len += crypto_send(fp, &vtemp);
- value_free(&vtemp);
- }
- break;
- /*
- * Send response in Guillou-Quisquater (GQ) identity scheme.
- */
- case CRYPTO_GQ | CRYPTO_RESP:
- if ((rval = crypto_bob2(ep, &vtemp)) == XEVNT_OK) {
- len += crypto_send(fp, &vtemp);
- value_free(&vtemp);
- }
- break;
- /*
- * Send challenge in MV identity scheme.
- */
- case CRYPTO_MV:
- if ((peer = findpeerbyassoc(ep->pkt[0])) == NULL) {
- rval = XEVNT_ERR;
- break;
- }
- if ((rval = crypto_alice3(peer, &vtemp)) == XEVNT_OK) {
- len += crypto_send(fp, &vtemp);
- value_free(&vtemp);
- }
- break;
- /*
- * Send response in MV identity scheme.
- */
- case CRYPTO_MV | CRYPTO_RESP:
- if ((rval = crypto_bob3(ep, &vtemp)) == XEVNT_OK) {
- len += crypto_send(fp, &vtemp);
- value_free(&vtemp);
- }
- break;
- /*
- * Send certificate sign response. The integrity of the request
- * certificate has already been verified on the receive side.
- * Sign the response using the local server key. Use the
- * filestamp from the request and use the timestamp as the
- * current time. Light the error bit if the certificate is
- * invalid or contains an unverified signature.
- */
- case CRYPTO_SIGN | CRYPTO_RESP:
- if ((rval = cert_sign(ep, &vtemp)) == XEVNT_OK)
- len += crypto_send(fp, &vtemp);
- value_free(&vtemp);
- break;
- /*
- * Send public key and signature. Use the values from the public
- * key.
- */
- case CRYPTO_COOK:
- len += crypto_send(fp, &pubkey);
- break;
- /*
- * Encrypt and send cookie and signature. Light the error bit if
- * anything goes wrong.
- */
- case CRYPTO_COOK | CRYPTO_RESP:
- if ((opcode & 0xffff) < VALUE_LEN) {
- rval = XEVNT_LEN;
- break;
- }
- if (PKT_MODE(xpkt->li_vn_mode) == MODE_SERVER) {
- tcookie = cookie;
- } else {
- if ((peer = findpeerbyassoc(associd)) == NULL) {
- rval = XEVNT_ERR;
- break;
- }
- tcookie = peer->pcookie;
- }
- if ((rval = crypto_encrypt(ep, &vtemp, &tcookie)) ==
- XEVNT_OK)
- len += crypto_send(fp, &vtemp);
- value_free(&vtemp);
- break;
- /*
- * Find peer and send autokey data and signature in broadcast
- * server and symmetric modes. Use the values in the autokey
- * structure. If no association is found, either the server has
- * restarted with new associations or some perp has replayed an
- * old message, in which case light the error bit.
- */
- case CRYPTO_AUTO | CRYPTO_RESP:
- if ((peer = findpeerbyassoc(associd)) == NULL) {
- rval = XEVNT_ERR;
- break;
- }
- peer->flags &= ~FLAG_ASSOC;
- len += crypto_send(fp, &peer->sndval);
- break;
- /*
- * Send leapseconds table and signature. Use the values from the
- * tai structure. If no table has been loaded, just send an
- * empty request.
- */
- case CRYPTO_TAI:
- case CRYPTO_TAI | CRYPTO_RESP:
- if (crypto_flags & CRYPTO_FLAG_TAI)
- len += crypto_send(fp, &tai_leap);
- break;
- /*
- * Default - Fall through for requests; for unknown responses,
- * flag as error.
- */
- default:
- if (opcode & CRYPTO_RESP)
- rval = XEVNT_ERR;
- }
- /*
- * In case of error, flame the log. If a request, toss the
- * puppy; if a response, return so the sender can flame, too.
- */
- if (rval != XEVNT_OK) {
- opcode |= CRYPTO_ERROR;
- snprintf(statstr, NTP_MAXSTRLEN,
- "error %x opcode %x", rval, opcode);
- record_crypto_stats(srcadr_sin, statstr);
- report_event(rval, NULL);
- #ifdef DEBUG
- if (debug)
- printf("crypto_xmit: %s\n", statstr);
- #endif
- if (!(opcode & CRYPTO_RESP))
- return (0);
- }
- /*
- * Round up the field length to a multiple of 8 bytes and save
- * the request code and length.
- */
- len = ((len + 7) / 8) * 8;
- fp->opcode = htonl((opcode & 0xffff0000) | len);
- #ifdef DEBUG
- if (debug)
- printf(
- "crypto_xmit: flags 0x%x ext offset %d len %u code 0x%x assocID %d\n",
- crypto_flags, start, len, opcode >> 16, associd);
- #endif
- return (len);
- }
- /*
- * crypto_verify - parse and verify the extension field and value
- *
- * Returns
- * XEVNT_OK success
- * XEVNT_LEN bad field format or length
- * XEVNT_TSP bad timestamp
- * XEVNT_FSP bad filestamp
- * XEVNT_PUB bad or missing public key
- * XEVNT_SGL bad signature length
- * XEVNT_SIG signature not verified
- * XEVNT_ERR protocol error
- */
- static int
- crypto_verify(
- struct exten *ep, /* extension pointer */
- struct value *vp, /* value pointer */
- struct peer *peer /* peer structure pointer */
- )
- {
- EVP_PKEY *pkey; /* server public key */
- EVP_MD_CTX ctx; /* signature context */
- tstamp_t tstamp, tstamp1 = 0; /* timestamp */
- tstamp_t fstamp, fstamp1 = 0; /* filestamp */
- u_int vallen; /* value length */
- u_int siglen; /* signature length */
- u_int opcode, len;
- int i;
- /*
- * We require valid opcode and field lengths, timestamp,
- * filestamp, public key, digest, signature length and
- * signature, where relevant. Note that preliminary length
- * checks are done in the main loop.
- */
- len = ntohl(ep->opcode) & 0x0000ffff;
- opcode = ntohl(ep->opcode) & 0xffff0000;
- /*
- * Check for valid operation code and protocol. The opcode must
- * not have the error bit set. If a response, it must have a
- * value header. If a request and does not contain a value
- * header, no need for further checking.
- */
- if (opcode & CRYPTO_ERROR)
- return (XEVNT_ERR);
- if (opcode & CRYPTO_RESP) {
- if (len < VALUE_LEN)
- return (XEVNT_LEN);
- } else {
- if (len < VALUE_LEN)
- return (XEVNT_OK);
- }
- /*
- * We have a value header. Check for valid field lengths. The
- * field length must be long enough to contain the value header,
- * value and signature. Note both the value and signature fields
- * are rounded up to the next word.
- */
- vallen = ntohl(ep->vallen);
- i = (vallen + 3) / 4;
- siglen = ntohl(ep->pkt[i++]);
- if (len < VALUE_LEN + ((vallen + 3) / 4) * 4 + ((siglen + 3) /
- 4) * 4)
- return (XEVNT_LEN);
- /*
- * Punt if this is a response with no data. Punt if this is a
- * request and a previous response is pending.
- */
- if (opcode & CRYPTO_RESP) {
- if (vallen == 0)
- return (XEVNT_LEN);
- } else {
- if (peer->cmmd != NULL)
- return (XEVNT_LEN);
- }
- /*
- * Check for valid timestamp and filestamp. If the timestamp is
- * zero, the sender is not synchronized and signatures are
- * disregarded. If not, the timestamp must not precede the
- * filestamp. The timestamp and filestamp must not precede the
- * corresponding values in the value structure, if present. Once
- * the autokey values have been installed, the timestamp must
- * always be later than the corresponding value in the value
- * structure. Duplicate timestamps are illegal once the cookie
- * has been validated.
- */
- tstamp = ntohl(ep->tstamp);
- fstamp = ntohl(ep->fstamp);
- if (tstamp == 0)
- return (XEVNT_OK);
- if (tstamp < fstamp)
- return (XEVNT_TSP);
- if (vp != NULL) {
- tstamp1 = ntohl(vp->tstamp);
- fstamp1 = ntohl(vp->fstamp);
- if ((tstamp < tstamp1 || (tstamp == tstamp1 &&
- (peer->crypto & CRYPTO_FLAG_AUTO))))
- return (XEVNT_TSP);
- if ((tstamp < fstamp1 || fstamp < fstamp1))
- return (XEVNT_FSP);
- }
- /*
- * Check for valid signature length, public key and digest
- * algorithm.
- */
- if (crypto_flags & peer->crypto & CRYPTO_FLAG_PRIV)
- pkey = sign_pkey;
- else
- pkey = peer->pkey;
- if (siglen == 0 || pkey == NULL || peer->digest == NULL)
- return (XEVNT_OK);
- if (siglen != (u_int)EVP_PKEY_size(pkey))
- return (XEVNT_SGL);
- /*
- * Darn, I thought we would never get here. Verify the
- * signature. If the identity exchange is verified, light the
- * proventic bit. If no client identity scheme is specified,
- * avoid doing the sign exchange.
- */
- EVP_VerifyInit(&ctx, peer->digest);
- EVP_VerifyUpdate(&ctx, (u_char *)&ep->tstamp, vallen + 12);
- if (EVP_VerifyFinal(&ctx, (u_char *)&ep->pkt[i], siglen, pkey) <= 0)
- return (XEVNT_SIG);
- if (peer->crypto & CRYPTO_FLAG_VRFY) {
- peer->crypto |= CRYPTO_FLAG_PROV;
- if (!(crypto_flags & CRYPTO_FLAG_MASK))
- peer->crypto |= CRYPTO_FLAG_SIGN;
- }
- return (XEVNT_OK);
- }
- /*
- * crypto_encrypt - construct encrypted cookie and signature from
- * extension field and cookie
- *
- * Returns
- * XEVNT_OK success
- * XEVNT_PUB bad or missing public key
- * XEVNT_CKY bad or missing cookie
- * XEVNT_PER host certificate expired
- */
- static int
- crypto_encrypt(
- struct exten *ep, /* extension pointer */
- struct value *vp, /* value pointer */
- keyid_t *cookie /* server cookie */
- )
- {
- EVP_PKEY *pkey; /* public key */
- EVP_MD_CTX ctx; /* signature context */
- tstamp_t tstamp; /* NTP timestamp */
- u_int32 temp32;
- u_int len;
- u_char *ptr;
- /*
- * Extract the public key from the request.
- */
- len = ntohl(ep->vallen);
- ptr = (u_char *)ep->pkt;
- pkey = d2i_PublicKey(EVP_PKEY_RSA, NULL, &ptr, len);
- if (pkey == NULL) {
- msyslog(LOG_ERR, "crypto_encrypt %s\n",
- ERR_error_string(ERR_get_error(), NULL));
- return (XEVNT_PUB);
- }
- /*
- * Encrypt the cookie, encode in ASN.1 and sign.
- */
- tstamp = crypto_time();
- memset(vp, 0, sizeof(struct value));
- vp->tstamp = htonl(tstamp);
- vp->fstamp = hostval.tstamp;
- len = EVP_PKEY_size(pkey);
- vp->vallen = htonl(len);
- vp->ptr = emalloc(len);
- temp32 = htonl(*cookie);
- if (!RSA_public_encrypt(4, (u_char *)&temp32, vp->ptr,
- pkey->pkey.rsa, RSA_PKCS1_OAEP_PADDING)) {
- msyslog(LOG_ERR, "crypto_encrypt %s\n",
- ERR_error_string(ERR_get_error(), NULL));
- EVP_PKEY_free(pkey);
- return (XEVNT_CKY);
- }
- EVP_PKEY_free(pkey);
- vp->siglen = 0;
- if (tstamp == 0)
- return (XEVNT_OK);
- if (tstamp < cinfo->first || tstamp > cinfo->last)
- return (XEVNT_PER);
- vp->sig = emalloc(sign_siglen);
- EVP_SignInit(&ctx, sign_digest);
- EVP_SignUpdate(&ctx, (u_char *)&vp->tstamp, 12);
- EVP_SignUpdate(&ctx, vp->ptr, len);
- if (EVP_SignFinal(&ctx, vp->sig, &len, sign_pkey))
- vp->siglen = htonl(len);
- return (XEVNT_OK);
- }
- /*
- * crypto_ident - construct extension field for identity scheme
- *
- * This routine determines which identity scheme is in use and
- * constructs an extension field for that scheme.
- */
- u_int
- crypto_ident(
- struct peer *peer /* peer structure pointer */
- )
- {
- char filename[MAXFILENAME + 1];
- /*
- * If the server identity has already been verified, no further
- * action is necessary. Otherwise, try to load the identity file
- * of the certificate issuer. If the issuer file is not found,
- * try the host file. If nothing found, declare a cryptobust.
- * Note we can't get here unless the trusted certificate has
- * been found and the CRYPTO_FLAG_VALID bit is set, so the
- * certificate issuer is valid.
- */
- if (peer->ident_pkey != NULL)
- EVP_PKEY_free(peer->ident_pkey);
- if (peer->crypto & CRYPTO_FLAG_GQ) {
- snprintf(filename, MAXFILENAME, "ntpkey_gq_%s",
- peer->issuer);
- peer->ident_pkey = crypto_key(filename, &peer->fstamp);
- if (peer->ident_pkey != NULL)
- return (CRYPTO_GQ);
- snprintf(filename, MAXFILENAME, "ntpkey_gq_%s",
- sys_hostname);
- peer->ident_pkey = crypto_key(filename, &peer->fstamp);
- if (peer->ident_pkey != NULL)
- return (CRYPTO_GQ);
- }
- if (peer->crypto & CRYPTO_FLAG_IFF) {
- snprintf(filename, MAXFILENAME, "ntpkey_iff_%s",
- peer->issuer);
- peer->ident_pkey = crypto_key(filename, &peer->fstamp);
- if (peer->ident_pkey != NULL)
- return (CRYPTO_IFF);
- snprintf(filename, MAXFILENAME, "ntpkey_iff_%s",
- sys_hostname);
- peer->ident_pkey = crypto_key(filename, &peer->fstamp);
- if (peer->ident_pkey != NULL)
- return (CRYPTO_IFF);
- }
- if (peer->crypto & CRYPTO_FLAG_MV) {
- snprintf(filename, MAXFILENAME, "ntpkey_mv_%s",
- peer->issuer);
- peer->ident_pkey = crypto_key(filename, &peer->fstamp);
- if (peer->ident_pkey != NULL)
- return (CRYPTO_MV);
- snprintf(filename, MAXFILENAME, "ntpkey_mv_%s",
- sys_hostname);
- peer->ident_pkey = crypto_key(filename, &peer->fstamp);
- if (peer->ident_pkey != NULL)
- return (CRYPTO_MV);
- }
- /*
- * No compatible identity scheme is available. Life is hard.
- */
- msyslog(LOG_INFO,
- "crypto_ident: no compatible identity scheme found");
- return (0);
- }
- /*
- * crypto_args - construct extension field from arguments
- *
- * This routine creates an extension field with current timestamps and
- * specified opcode, association ID and optional string. Note that the
- * extension field is created here, but freed after the crypto_xmit()
- * call in the protocol module.
- *
- * Returns extension field pointer (no errors).
- */
- struct exten *
- crypto_args(
- struct peer *peer, /* peer structure pointer */
- u_int opcode, /* operation code */
- char *str /* argument string */
- )
- {
- tstamp_t tstamp; /* NTP timestamp */
- struct exten *ep; /* extension field pointer */
- u_int len; /* extension field length */
- tstamp = crypto_time();
- len = sizeof(struct exten);
- if (str != NULL)
- len += strlen(str);
- ep = emalloc(len);
- memset(ep, 0, len);
- if (opcode == 0)
- return (ep);
- ep->opcode = htonl(opcode + len);
- /*
- * If a response, send our ID; if a request, send the
- * responder's ID.
- */
- if (opcode & CRYPTO_RESP)
- ep->associd = htonl(peer->associd);
- else
- ep->associd = htonl(peer->assoc);
- ep->tstamp = htonl(tstamp);
- ep->fstamp = hostval.tstamp;
- ep->vallen = 0;
- if (str != NULL) {
- ep->vallen = htonl(strlen(str));
- memcpy((char *)ep->pkt, str, strlen(str));
- } else {
- ep->pkt[0] = peer->associd;
- }
- return (ep);
- }
- /*
- * crypto_send - construct extension field from value components
- *
- * Returns extension field length. Note: it is not polite to send a
- * nonempty signature with zero timestamp or a nonzero timestamp with
- * empty signature, but these rules are not enforced here.
- */
- u_int
- crypto_send(
- struct exten *ep, /* extension field pointer */
- struct value *vp /* value pointer */
- )
- {
- u_int len, temp32;
- int i;
- /*
- * Copy data. If the data field is empty or zero length, encode
- * an empty value with length zero.
- */
- ep->tstamp = vp->tstamp;
- ep->fstamp = vp->fstamp;
- ep->vallen = vp->vallen;
- len = 12;
- temp32 = ntohl(vp->vallen);
- if (temp32 > 0 && vp->ptr != NULL)
- memcpy(ep->pkt, vp->ptr, temp32);
- /*
- * Copy signature. If the signature field is empty or zero
- * length, encode an empty signature with length zero.
- */
- i = (temp32 + 3) / 4;
- len += i * 4 + 4;
- ep->pkt[i++] = vp->siglen;
- temp32 = ntohl(vp->siglen);
- if (temp32 > 0 && vp->sig != NULL)
- memcpy(&ep->pkt[i], vp->sig, temp32);
- len += temp32;
- return (len);
- }
- /*
- * crypto_update - compute new public value and sign extension fields
- *
- * This routine runs periodically, like once a day, and when something
- * changes. It updates the timestamps on three value structures and one
- * value structure list, then signs all the structures:
- *
- * hostval host name (not signed)
- * pubkey public key
- * cinfo certificate info/value list
- * tai_leap leapseconds file
- *
- * Filestamps are proventicated data, so this routine is run only when
- * the host has been synchronized to a proventicated source. Thus, the
- * timestamp is proventicated, too, and can be used to deflect
- * clogging attacks and even cook breakfast.
- *
- * Returns void (no errors)
- */
- void
- crypto_update(void)
- {
- EVP_MD_CTX ctx; /* message digest context */
- struct cert_info *cp, *cpn; /* certificate info/value */
- char statstr[NTP_MAXSTRLEN]; /* statistics for filegen */
- tstamp_t tstamp; /* NTP timestamp */
- u_int len;
- if ((tstamp = crypto_time()) == 0)
- return;
- hostval.tstamp = htonl(tstamp);
- /*
- * Sign public key and timestamps. The filestamp is derived from
- * the host key file extension from wherever the file was
- * generated.
- */
- if (pubkey.vallen != 0) {
- pubkey.tstamp = hostval.tstamp;
- pubkey.siglen = 0;
- if (pubkey.sig == NULL)
- pubkey.sig = emalloc(sign_siglen);
- EVP_SignInit(&ctx, sign_digest);
- EVP_SignUpdate(&ctx, (u_char *)&pubkey, 12);
- EVP_SignUpdate(&ctx, pubkey.ptr, ntohl(pubkey.vallen));
- if (EVP_SignFinal(&ctx, pubkey.sig, &len, sign_pkey))
- pubkey.siglen = htonl(len);
- }
- /*
- * Sign certificates and timestamps. The filestamp is derived
- * from the certificate file extension from wherever the file
- * was generated. Note we do not throw expired certificates
- * away; they may have signed younger ones.
- */
- for (cp = cinfo; cp != NULL; cp = cpn) {
- cpn = cp->link;
- cp->cert.tstamp = hostval.tstamp;
- cp->cert.siglen = 0;
- if (cp->cert.sig == NULL)
- cp->cert.sig = emalloc(sign_siglen);
- EVP_SignInit(&ctx, sign_digest);
- EVP_SignUpdate(&ctx, (u_char *)&cp->cert, 12);
- EVP_SignUpdate(&ctx, cp->cert.ptr,
- ntohl(cp->cert.vallen));
- if (EVP_SignFinal(&ctx, cp->cert.sig, &len, sign_pkey))
- cp->cert.siglen = htonl(len);
- }
- /*
- * Sign leapseconds table and timestamps. The filestamp is
- * derived from the leapsecond file extension from wherever the
- * file was generated.
- */
- if (tai_leap.vallen != 0) {
- tai_leap.tstamp = hostval.tstamp;
- tai_leap.siglen = 0;
- if (tai_leap.sig == NULL)
- tai_leap.sig = emalloc(sign_siglen);
- EVP_SignInit(&ctx, sign_digest);
- EVP_SignUpdate(&ctx, (u_char *)&tai_leap, 12);
- EVP_SignUpdate(&ctx, tai_leap.ptr,
- ntohl(tai_leap.vallen));
- if (EVP_SignFinal(&ctx, tai_leap.sig, &len, sign_pkey))
- tai_leap.siglen = htonl(len);
- }
- snprintf(statstr, NTP_MAXSTRLEN,
- "update ts %u", ntohl(hostval.tstamp));
- record_crypto_stats(NULL, statstr);
- #ifdef DEBUG
- if (debug)
- printf("crypto_update: %s\n", statstr);
- #endif
- }
- /*
- * value_free - free value structure components.
- *
- * Returns void (no errors)
- */
- void
- value_free(
- struct value *vp /* value structure */
- )
- {
- if (vp->ptr != NULL)
- free(vp->ptr);
- if (vp->sig != NULL)
- free(vp->sig);
- memset(vp, 0, sizeof(struct value));
- }
- /*
- * crypto_time - returns current NTP time in seconds.
- */
- tstamp_t
- crypto_time()
- {
- l_fp tstamp; /* NTP time */ L_CLR(&tstamp);
- L_CLR(&tstamp);
- if (sys_leap != LEAP_NOTINSYNC)
- get_systime(&tstamp);
- return (tstamp.l_ui);
- }
- /*
- * asn2ntp - convert ASN1_TIME time structure to NTP time in seconds.
- */
- u_long
- asn2ntp (
- ASN1_TIME *asn1time /* pointer to ASN1_TIME structure */
- )
- {
- char *v; /* pointer to ASN1_TIME string */
- struct tm tm; /* used to convert to NTP time */
- /*
- * Extract time string YYMMDDHHMMSSZ from ASN1 time structure.
- * Note that the YY, MM, DD fields start with one, the HH, MM,
- * SS fiels start with zero and the Z character should be 'Z'
- * for UTC. Also note that years less than 50 map to years
- * greater than 100. Dontcha love ASN.1? Better than MIL-188.
- */
- if (asn1time->length > 13)
- return ((u_long)(~0)); /* We can't use -1 here. It's invalid */
- v = (char *)asn1time->data;
- tm.tm_year = (v[0] - '0') * 10 + v[1] - '0';
- if (tm.tm_year < 50)
- tm.tm_year += 100;
- tm.tm_mon = (v[2] - '0') * 10 + v[3] - '0' - 1;
- tm.tm_mday = (v[4] - '0') * 10 + v[5] - '0';
- tm.tm_hour = (v[6] - '0') * 10 + v[7] - '0';
- tm.tm_min = (v[8] - '0') * 10 + v[9] - '0';
- tm.tm_sec = (v[10] - '0') * 10 + v[11] - '0';
- tm.tm_wday = 0;
- tm.tm_yday = 0;
- tm.tm_isdst = 0;
- return (timegm(&tm) + JAN_1970);
- }
- /*
- * bigdig() - compute a BIGNUM MD5 hash of a BIGNUM number.
- */
- static int
- bighash(
- BIGNUM *bn, /* BIGNUM * from */
- BIGNUM *bk /* BIGNUM * to */
- )
- {
- EVP_MD_CTX ctx; /* message digest context */
- u_char dgst[EVP_MAX_MD_SIZE]; /* message digest */
- u_char *ptr; /* a BIGNUM as binary string */
- u_int len;
- len = BN_num_bytes(bn);
- ptr = emalloc(len);
- BN_bn2bin(bn, ptr);
- EVP_DigestInit(&ctx, EVP_md5());
- EVP_DigestUpdate(&ctx, ptr, len);
- EVP_DigestFinal(&ctx, dgst, &len);
- BN_bin2bn(dgst, len, bk);
- /* XXX MEMLEAK? free ptr? */
- return (1);
- }
- /*
- ***********************************************************************
- * *
- * The following routines implement the Schnorr (IFF) identity scheme *
- * *
- ***********************************************************************
- *
- * The Schnorr (IFF) identity scheme is intended for use when
- * the ntp-genkeys program does not generate the certificates used in
- * the protocol and the group key cannot be conveyed in the certificate
- * itself. For this purpose, new generations of IFF values must be
- * securely transmitted to all members of the group before use. The
- * scheme is self contained and independent of new generations of host
- * keys, sign keys and certificates.
- *
- * The IFF identity scheme is based on DSA cryptography and algorithms
- * described in Stinson p. 285. The IFF values hide in a DSA cuckoo
- * structure, but only the primes and generator are used. The p is a
- * 512-bit prime, q a 160-bit prime that divides p - 1 and is a qth root
- * of 1 mod p; that is, g^q = 1 mod p. The TA rolls primvate random
- * group key b disguised as a DSA structure member, then computes public
- * key g^(q - b). These values are shared only among group members and
- * never revealed in messages. Alice challenges Bob to confirm identity
- * using the protocol described below.
- *
- * How it works
- *
- * The scheme goes like this. Both Alice and Bob have the public primes
- * p, q and generator g. The TA gives private key b to Bob and public
- * key v = g^(q - a) mod p to Alice.
- *
- * Alice rolls new random challenge r and sends to Bob in the IFF
- * request message. Bob rolls new random k, then computes y = k + b r
- * mod q and x = g^k mod p and sends (y, hash(x)) to Alice in the
- * response message. Besides making the response shorter, the hash makes
- * it effectivey impossible for an intruder to solve for b by observing
- * a number of these messages.
- *
- * Alice receives the response and computes g^y v^r mod p. After a bit
- * of algebra, this simplifies to g^k. If the hash of this result
- * matches hash(x), Alice knows that Bob has the group key b. The signed
- * response binds this knowledge to Bob's private key and the public key
- * previously received in his certificate.
- *
- * crypto_alice - construct Alice's challenge in IFF scheme
- *
- * Returns
- * XEVNT_OK success
- * XEVNT_PUB bad or missing public key
- * XEVNT_ID bad or missing group key
- */
- static int
- crypto_alice(
- struct peer *peer, /* peer pointer */
- struct value *vp /* value pointer */
- )
- {
- DSA *dsa; /* IFF parameters */
- BN_CTX *bctx; /* BIGNUM context */
- EVP_MD_CTX ctx; /* signature context */
- tstamp_t tstamp;
- u_int len;
- /*
- * The identity parameters must have correct format and content.
- */
- if (peer->ident_pkey == NULL)
- return (XEVNT_ID);
- if ((dsa = peer->ident_pkey->pkey.dsa) == NULL) {
- msyslog(LOG_INFO, "crypto_alice: defective key");
- return (XEVNT_PUB);
- }
- /*
- * Roll new random r (0 < r < q). The OpenSSL library has a bug
- * omitting BN_rand_range, so we have to do it the hard way.
- */
- bctx = BN_CTX_new();
- len = BN_num_bytes(dsa->q);
- if (peer->iffval != NULL)
- BN_free(peer->iffval);
- peer->iffval = BN_new();
- BN_rand(peer->iffval, len * 8, -1, 1); /* r */
- BN_mod(peer->iffval, peer->iffval, dsa->q, bctx);
- BN_CTX_free(bctx);
- /*
- * Sign and send to Bob. The filestamp is from the local file.
- */
- tstamp = crypto_time();
- memset(vp, 0, sizeof(struct value));
- vp->tstamp = htonl(tstamp);
- vp->fstamp = htonl(peer->fstamp);
- vp->vallen = htonl(len);
- vp->ptr = emalloc(len);
- BN_bn2bin(peer->iffval, vp->ptr);
- vp->siglen = 0;
- if (tstamp == 0)
- return (XEVNT_OK);
- if (tstamp < cinfo->first || tstamp > cinfo->last)
- return (XEVNT_PER);
- vp->sig = emalloc(sign_siglen);
- EVP_SignInit(&ctx, sign_digest);
- EVP_SignUpdate(&ctx, (u_char *)&vp->tstamp, 12);
- EVP_SignUpdate(&ctx, vp->ptr, len);
- if (EVP_SignFinal(&ctx, vp->sig, &len, sign_pkey))
- vp->siglen = htonl(len);
- return (XEVNT_OK);
- }
- /*
- * crypto_bob - construct Bob's response to Alice's challenge
- *
- * Returns
- * XEVNT_OK success
- * XEVNT_ID bad or missing group key
- * XEVNT_ERR protocol error
- * XEVNT_PER host expired certificate
- */
- static int
- crypto_bob(
- struct exten *ep, /* extension pointer */
- struct value *vp /* value pointer */
- )
- {
- DSA *dsa; /* IFF parameters */
- DSA_SIG *sdsa; /* DSA signature context fake */
- BN_CTX *bctx; /* BIGNUM context */
- EVP_MD_CTX ctx; /* signature context */
- tstamp_t tstamp; /* NTP timestamp */
- BIGNUM *bn, *bk, *r;
- u_char *ptr;
- u_int len;
- /*
- * If the IFF parameters are not valid, something awful
- * happened or we are being tormented.
- */
- if (iffpar_pkey == NULL) {
- msyslog(LOG_INFO, "crypto_bob: scheme unavailable");
- return (XEVNT_ID);
- }
- dsa = iffpar_pkey->pkey.dsa;
- /*
- * Extract r from the challenge.
- */
- len = ntohl(ep->vallen);
- if ((r = BN_bin2bn((u_char *)ep->pkt, len, NULL)) == NULL) {
- msyslog(LOG_ERR, "crypto_bob %s\n",
- ERR_error_string(ERR_get_error(), NULL));
- return (XEVNT_ERR);
- }
- /*
- * Bob rolls random k (0 < k < q), computes y = k + b r mod q
- * and x = g^k mod p, then sends (y, hash(x)) to Alice.
- */
- bctx = BN_CTX_new(); bk = BN_new(); bn = BN_new();
- sdsa = DSA_SIG_new();
- BN_rand(bk, len * 8, -1, 1); /* k */
- BN_mod_mul(bn, dsa->priv_key, r, dsa->q, bctx); /* b r mod q */
- BN_add(bn, bn, bk);
- BN_mod(bn, bn, dsa->q, bctx); /* k + b r mod q */
- sdsa->r = BN_dup(bn);
- BN_mod_exp(bk, dsa->g, bk, dsa->p, bctx); /* g^k mod p */
- bighash(bk, bk);
- sdsa->s = BN_dup(bk);
- BN_CTX_free(bctx);
- BN_free(r); BN_free(bn); BN_free(bk);
- /*
- * Encode the values in ASN.1 and sign.
- */
- tstamp = crypto_time();
- memset(vp, 0, sizeof(struct value));
- vp->tstamp = htonl(tstamp);
- vp->fstamp = htonl(if_fstamp);
- len = i2d_DSA_SIG(sdsa, NULL);
- if (len <= 0) {
- msyslog(LOG_ERR, "crypto_bob %s\n",
- ERR_error_string(ERR_get_error(), NULL));
- DSA_SIG_free(sdsa);
- return (XEVNT_ERR);
- }
- vp->vallen = htonl(len);
- ptr = emalloc(len);
- vp->ptr = ptr;
- i2d_DSA_SIG(sdsa, &ptr);
- DSA_SIG_free(sdsa);
- vp->siglen = 0;
- if (tstamp == 0)
- return (XEVNT_OK);
- if (tstamp < cinfo->first || tstamp > cinfo->last)
- return (XEVNT_PER);
- vp->sig = emalloc(sign_siglen);
- EVP_SignInit(&ctx, sign_digest);
- EVP_SignUpdate(&ctx, (u_char *)&vp->tstamp, 12);
- EVP_SignUpdate(&ctx, vp->ptr, len);
- if (EVP_SignFinal(&ctx, vp->sig, &len, sign_pkey))
- vp->siglen = htonl(len);
- return (XEVNT_OK);
- }
- /*
- * crypto_iff - verify Bob's response to Alice's challenge
- *
- * Returns
- * XEVNT_OK success
- * XEVNT_PUB bad or missing public key
- * XEVNT_ID bad or missing group key
- * XEVNT_FSP bad filestamp
- */
- int
- crypto_iff(
- struct exten *ep, /* extension pointer */
- struct peer *peer /* peer structure pointer */
- )
- {
- DSA *dsa; /* IFF parameters */
- BN_CTX *bctx; /* BIGNUM context */
- DSA_SIG *sdsa; /* DSA parameters */
- BIGNUM *bn, *bk;
- u_int len;
- const u_char *ptr;
- int temp;
- /*
- * If the IFF parameters are not valid or no challenge was sent,
- * something awful happened or we are being tormented.
- */
- if (peer->ident_pkey == NULL) {
- msyslog(LOG_INFO, "crypto_iff: scheme unavailable");
- return (XEVNT_ID);
- }
- if (ntohl(ep->fstamp) != peer->fstamp) {
- msyslog(LOG_INFO, "crypto_iff: invalid filestamp %u",
- ntohl(ep->fstamp));
- return (XEVNT_FSP);
- }
- if ((dsa = peer->ident_pkey->pkey.dsa) == NULL) {
- msyslog(LOG_INFO, "crypto_iff: defective key");
- return (XEVNT_PUB);
- }
- if (peer->iffval == NULL) {
- msyslog(LOG_INFO, "crypto_iff: missing challenge");
- return (XEVNT_ID);
- }
- /*
- * Extract the k + b r and g^k values from the response.
- */
- bctx = BN_CTX_new(); bk = BN_new(); bn = BN_new();
- len = ntohl(ep->vallen);
- ptr = (const u_char *)ep->pkt;
- if ((sdsa = d2i_DSA_SIG(NULL, &ptr, len)) == NULL) {
- msyslog(LOG_ERR, "crypto_iff %s\n",
- ERR_error_string(ERR_get_error(), NULL));
- return (XEVNT_ERR);
- }
- /*
- * Compute g^(k + b r) g^(q - b)r mod p.
- */
- BN_mod_exp(bn, dsa->pub_key, peer->iffval, dsa->p, bctx);
- BN_mod_exp(bk, dsa->g, sdsa->r, dsa->p, bctx);
- BN_mod_mul(bn, bn, bk, dsa->p, bctx);
- /*
- * Verify the hash of the result matches hash(x).
- */
- bighash(bn, bn);
- temp = BN_cmp(bn, sdsa->s);
- BN_free(bn); BN_free(bk); BN_CTX_free(bctx);
- BN_free(peer->iffval);
- peer->iffval = NULL;
- DSA_SIG_free(sdsa);
- if (temp == 0)
- return (XEVNT_OK);
- else
- return (XEVNT_ID);
- }
- /*
- ***********************************************************************
- * *
- * The following routines implement the Guillou-Quisquater (GQ) *
- * identity scheme *
- * *
- ***********************************************************************
- *
- * The Guillou-Quisquater (GQ) identity scheme is intended for use when
- * the ntp-genkeys program generates the certificates used in the
- * protocol and the group key can be conveyed in a certificate extension
- * field. The scheme is self contained and independent of new
- * generations of host keys, sign keys and certificates.
- *
- * The GQ identity scheme is based on RSA cryptography and algorithms
- * described in Stinson p. 300 (with errors). The GQ values hide in a
- * RSA cuckoo structure, but only the modulus is used. The 512-bit
- * public modulus is n = p q, where p and q are secret large primes. The
- * TA rolls random group key b disguised as a RSA structure member.
- * Except for the public key, these values are shared only among group
- * members and never revealed in messages.
- *
- * When rolling new certificates, Bob recomputes the private and
- * public keys. The private key u is a random roll, while the public key
- * is the inverse obscured by the group key v = (u^-1)^b. These values
- * replace the private and public keys normally generated by the RSA
- * scheme. Alice challenges Bob to confirm identity using the protocol
- * described below.
- *
- * How it works
- *
- * The scheme goes like this. Both Alice and Bob have the same modulus n
- * and some random b as the group key. These values are computed and
- * distributed in advance via secret means, although only the group key
- * b is truly secret. Each has a private random private key u and public
- * key (u^-1)^b, although not necessarily the same ones. Bob and Alice
- * can regenerate the key pair from time to time without affecting
- * operations. The public key is conveyed on the certificate in an
- * extension field; the private key is never revealed.
- *
- * Alice rolls new random challenge r and sends to Bob in the GQ
- * request message. Bob rolls new random k, then computes y = k u^r mod
- * n and x = k^b mod n and sends (y, hash(x)) to Alice in the response
- * message. Besides making the response shorter, the hash makes it
- * effectivey impossible for an intruder to solve for b by observing
- * a number of these messages.
- *
- * Alice receives the response and computes y^b v^r mod n. After a bit
- * of algebra, this simplifies to k^b. If the hash of this result
- * matches hash(x), Alice knows that Bob has the group key b. The signed
- * response binds this knowledge to Bob's private key and the public key
- * previously received in his certificate.
- *
- * crypto_alice2 - construct Alice's challenge in GQ scheme
- *
- * Returns
- * XEVNT_OK success
- * XEVNT_PUB bad or missing public key
- * XEVNT_ID bad or missing group key
- * XEVNT_PER host certificate expired
- */
- static int
- crypto_alice2(
- struct peer *peer, /* peer pointer */
- struct value *vp /* value pointer */
- )
- {
- RSA *rsa; /* GQ parameters */
- BN_CTX *bctx; /* BIGNUM context */
- EVP_MD_CTX ctx; /* signature context */
- tstamp_t tstamp;
- u_int len;
- /*
- * The identity parameters must have correct format and content.
- */
- if (peer->ident_pkey == NULL)
- return (XEVNT_ID);
- if ((rsa = peer->ident_pkey->pkey.rsa) == NULL) {
- msyslog(LOG_INFO, "crypto_alice2: defective key");
- return (XEVNT_PUB);
- }
- /*
- * Roll new random r (0 < r < n). The OpenSSL library has a bug
- * omitting BN_rand_range, so we have to do it the hard way.
- */
- bctx = BN_CTX_new();
- len = BN_num_bytes(rsa->n);
- if (peer->iffval != NULL)
- BN_free(peer->iffval);
- peer->iffval = BN_new();
- BN_rand(peer->iffval, len * 8, -1, 1); /* r mod n */
- BN_mod(peer->iffval, peer->iffval, rsa->n, bctx);
- BN_CTX_free(bctx);
- /*
- * Sign and send to Bob. The filestamp is from the local file.
- */
- tstamp = crypto_time();
- memset(vp, 0, sizeof(struct value));
- vp->tstamp = htonl(tstamp);
- vp->fstamp = htonl(peer->fstamp);
- vp->vallen = htonl(len);
- vp->ptr = emalloc(len);
- BN_bn2bin(peer->iffval, vp->ptr);
- vp->siglen = 0;
- if (tstamp == 0)
- return (XEVNT_OK);
- if (tstamp < cinfo->first || tstamp > cinfo->last)
- return (XEVNT_PER);
- vp->sig = emalloc(sign_siglen);
- EVP_SignInit(&ctx, sign_digest);
- EVP_SignUpdate(&ctx, (u_char *)&vp->tstamp, 12);
- EVP_SignUpdate(&ctx, vp->ptr, len);
- if (EVP_SignFinal(&ctx, vp->sig, &len, sign_pkey))
- vp->siglen = htonl(len);
- return (XEVNT_OK);
- }
- /*
- * crypto_bob2 - construct Bob's response to Alice's challenge
- *
- * Returns
- * XEVNT_OK success
- * XEVNT_ID bad or missing group key
- * XEVNT_ERR protocol error
- * XEVNT_PER host certificate expired
- */
- static int
- crypto_bob2(
- struct exten *ep, /* extension pointer */
- struct value *vp /* value pointer */
- )
- {
- RSA *rsa; /* GQ parameters */
- DSA_SIG *sdsa; /* DSA parameters */
- BN_CTX *bctx; /* BIGNUM context */
- EVP_MD_CTX ctx; /* signature context */
- tstamp_t tstamp; /* NTP timestamp */
- BIGNUM *r, *k, *g, *y;
- u_char *ptr;
- u_int len;
- /*
- * If the GQ parameters are not valid, something awful
- * happened or we are being tormented.
- */
- if (gqpar_pkey == NULL) {
- msyslog(LOG_INFO, "crypto_bob2: scheme unavailable");
- return (XEVNT_ID);
- }
- rsa = gqpar_pkey->pkey.rsa;
- /*
- * Extract r from the challenge.
- */
- len = ntohl(ep->vallen);
- if ((r = BN_bin2bn((u_char *)ep->pkt, len, NULL)) == NULL) {
- msyslog(LOG_ERR, "crypto_bob2 %s\n",
- ERR_error_string(ERR_get_error(), NULL));
- return (XEVNT_ERR);
- }
- /*
- * Bob rolls random k (0 < k < n), computes y = k u^r mod n and
- * x = k^b mod n, then sends (y, hash(x)) to Alice.
- */
- bctx = BN_CTX_new(); k = BN_new(); g = BN_new(); y = BN_new();
- sdsa = DSA_SIG_new();
- BN_rand(k, len * 8, -1, 1); /* k */
- BN_mod(k, k, rsa->n, bctx);
- BN_mod_exp(y, rsa->p, r, rsa->n, bctx); /* u^r mod n */
- BN_mod_mul(y, k, y, rsa->n, bctx); /* k u^r mod n */
- sdsa->r = BN_dup(y);
- BN_mod_exp(g, k, rsa->e, rsa->n, bctx); /* k^b mod n */
- bighash(g, g);
- sdsa->s = BN_dup(g);
- BN_CTX_free(bctx);
- BN_free(r); BN_free(k); BN_free(g); BN_free(y);
-
- /*
- * Encode the values in ASN.1 and sign.
- */
- tstamp = crypto_time();
- memset(vp, 0, sizeof(struct value));
- vp->tstamp = htonl(tstamp);
- vp->fstamp = htonl(gq_fstamp);
- len = i2d_DSA_SIG(sdsa, NULL);
- if (len <= 0) {
- msyslog(LOG_ERR, "crypto_bob2 %s\n",
- ERR_error_string(ERR_get_error(), NULL));
- DSA_SIG_free(sdsa);
- return (XEVNT_ERR);
- }
- vp->vallen = htonl(len);
- ptr = emalloc(len);
- vp->ptr = ptr;
- i2d_DSA_SIG(sdsa, &ptr);
- DSA_SIG_free(sdsa);
- vp->siglen = 0;
- if (tstamp == 0)
- return (XEVNT_OK);
- if (tstamp < cinfo->first || tstamp > cinfo->last)
- return (XEVNT_PER);
- vp->sig = emalloc(sign_siglen);
- EVP_SignInit(&ctx, sign_digest);
- EVP_SignUpdate(&ctx, (u_char *)&vp->tstamp, 12);
- EVP_SignUpdate(&ctx, vp->ptr, len);
- if (EVP_SignFinal(&ctx, vp->sig, &len, sign_pkey))
- vp->siglen = htonl(len);
- return (XEVNT_OK);
- }
- /*
- * crypto_gq - verify Bob's response to Alice's challenge
- *
- * Returns
- * XEVNT_OK success
- * XEVNT_PUB bad or missing public key
- * XEVNT_ID bad or missing group keys
- * XEVNT_ERR protocol error
- * XEVNT_FSP bad filestamp
- */
- int
- crypto_gq(
- struct exten *ep, /* extension pointer */
- struct peer *peer /* peer structure pointer */
- )
- {
- RSA *rsa; /* GQ parameters */
- BN_CTX *bctx; /* BIGNUM context */
- DSA_SIG *sdsa; /* RSA signature context fake */
- BIGNUM *y, *v;
- const u_char *ptr;
- u_int len;
- int temp;
- /*
- * If the GQ parameters are not valid or no challenge was sent,
- * something awful happened or we are being tormented.
- */
- if (peer->ident_pkey == NULL) {
- msyslog(LOG_INFO, "crypto_gq: scheme unavailable");
- return (XEVNT_ID);
- }
- if (ntohl(ep->fstamp) != peer->fstamp) {
- msyslog(LOG_INFO, "crypto_gq: invalid filestamp %u",
- ntohl(ep->fstamp));
- return (XEVNT_FSP);
- }
- if ((rsa = peer->ident_pkey->pkey.rsa) == NULL) {
- msyslog(LOG_INFO, "crypto_gq: defective key");
- return (XEVNT_PUB);
- }
- if (peer->iffval == NULL) {
- msyslog(LOG_INFO, "crypto_gq: missing challenge");
- return (XEVNT_ID);
- }
- /*
- * Extract the y = k u^r and hash(x = k^b) values from the
- * response.
- */
- bctx = BN_CTX_new(); y = BN_new(); v = BN_new();
- len = ntohl(ep->vallen);
- ptr = (const u_char *)ep->pkt;
- if ((sdsa = d2i_DSA_SIG(NULL, &ptr, len)) == NULL) {
- msyslog(LOG_ERR, "crypto_gq %s\n",
- ERR_error_string(ERR_get_error(), NULL));
- return (XEVNT_ERR);
- }
- /*
- * Compute v^r y^b mod n.
- */
- BN_mod_exp(v, peer->grpkey, peer->iffval, rsa->n, bctx);
- /* v^r mod n */
- BN_mod_exp(y, sdsa->r, rsa->e, rsa->n, bctx); /* y^b mod n */
- BN_mod_mul(y, v, y, rsa->n, bctx); /* v^r y^b mod n */
- /*
- * Verify the hash of the result matches hash(x).
- */
- bighash(y, y);
- temp = BN_cmp(y, sdsa->s);
- BN_CTX_free(bctx); BN_free(y); BN_free(v);
- BN_free(peer->iffval);
- peer->iffval = NULL;
- DSA_SIG_free(sdsa);
- if (temp == 0)
- return (XEVNT_OK);
- else
- return (XEVNT_ID);
- }
- /*
- ***********************************************************************
- * *
- * The following routines implement the Mu-Varadharajan (MV) identity *
- * scheme *
- * *
- ***********************************************************************
- */
- /*
- * The Mu-Varadharajan (MV) cryptosystem was originally intended when
- * servers broadcast messages to clients, but clients never send
- * messages to servers. There is one encryption key for the server and a
- * separate decryption key for each client. It operated something like a
- * pay-per-view satellite broadcasting system where the session key is
- * encrypted by the broadcaster and the decryption keys are held in a
- * tamperproof set-top box.
- *
- * The MV parameters and private encryption key hide in a DSA cuckoo
- * structure which uses the same parameters, but generated in a
- * different way. The values are used in an encryption scheme similar to
- * El Gamal cryptography and a polynomial formed from the expansion of
- * product terms (x - x[j]), as described in Mu, Y., and V.
- * Varadharajan: Robust and Secure Broadcasting, Proc. Indocrypt 2001,
- * 223-231. The paper has significant errors and serious omissions.
- *
- * Let q be the product of n distinct primes s'[j] (j = 1...n), where
- * each s'[j] has m significant bits. Let p be a prime p = 2 * q + 1, so
- * that q and each s'[j] divide p - 1 and p has M = n * m + 1
- * significant bits. The elements x mod q of Zq with the elements 2 and
- * the primes removed form a field Zq* valid for polynomial arithetic.
- * Let g be a generator of Zp; that is, gcd(g, p - 1) = 1 and g^q = 1
- * mod p. We expect M to be in the 500-bit range and n relatively small,
- * like 25, so the likelihood of a randomly generated element of x mod q
- * of Zq colliding with a factor of p - 1 is very small and can be
- * avoided. Associated with each s'[j] is an element s[j] such that s[j]
- * s'[j] = s'[j] mod q. We find s[j] as the quotient (q + s'[j]) /
- * s'[j]. These are the parameters of the scheme and they are expensive
- * to compute.
- *
- * We set up an instance of the scheme as follows. A set of random
- * values x[j] mod q (j = 1...n), are generated as the zeros of a
- * polynomial of order n. The product terms (x - x[j]) are expanded to
- * form coefficients a[i] mod q (i = 0...n) in powers of x. These are
- * used as exponents of the generator g mod p to generate the private
- * encryption key A. The pair (gbar, ghat) of public server keys and the
- * pairs (xbar[j], xhat[j]) (j = 1...n) of private client keys are used
- * to construct the decryption keys. The devil is in the details.
- *
- * The distinguishing characteristic of this scheme is the capability to
- * revoke keys. Included in the calculation of E, gbar and ghat is the
- * product s = prod(s'[j]) (j = 1...n) above. If the factor s'[j] is
- * subsequently removed from the product and E, gbar and ghat
- * recomputed, the jth client will no longer be able to compute E^-1 and
- * thus unable to decrypt the block.
- *
- * How it works
- *
- * The scheme goes like this. Bob has the server values (p, A, q, gbar,
- * ghat) and Alice the client values (p, xbar, xhat).
- *
- * Alice rolls new random challenge r (0 < r < p) and sends to Bob in
- * the MV request message. Bob rolls new random k (0 < k < q), encrypts
- * y = A^k mod p (a permutation) and sends (hash(y), gbar^k, ghat^k) to
- * Alice.
- *
- * Alice receives the response and computes the decryption key (the
- * inverse permutation) from previously obtained (xbar, xhat) and
- * (gbar^k, ghat^k) in the message. She computes the inverse, which is
- * unique by reasons explained in the ntp-keygen.c program sources. If
- * the hash of this result matches hash(y), Alice knows that Bob has the
- * group key b. The signed response binds this knowledge to Bob's
- * private key and the public key previously received in his
- * certificate.
- *
- * crypto_alice3 - construct Alice's challenge in MV scheme
- *
- * Returns
- * XEVNT_OK success
- * XEVNT_PUB bad or missing public key
- * XEVNT_ID bad or missing group key
- * XEVNT_PER host certificate expired
- */
- static int
- crypto_alice3(
- struct peer *peer, /* peer pointer */
- struct value *vp /* value pointer */
- )
- {
- DSA *dsa; /* MV parameters */
- BN_CTX *bctx; /* BIGNUM context */
- EVP_MD_CTX ctx; /* signature context */
- tstamp_t tstamp;
- u_int len;
- /*
- * The identity parameters must have correct format and content.
- */
- if (peer->ident_pkey == NULL)
- return (XEVNT_ID);
- if ((dsa = peer->ident_pkey->pkey.dsa) == NULL) {
- msyslog(LOG_INFO, "crypto_alice3: defective key");
- return (XEVNT_PUB);
- }
- /*
- * Roll new random r (0 < r < q). The OpenSSL library has a bug
- * omitting BN_rand_range, so we have to do it the hard way.
- */
- bctx = BN_CTX_new();
- len = BN_num_bytes(dsa->p);
- if (peer->iffval != NULL)
- BN_free(peer->iffval);
- peer->iffval = BN_new();
- BN_rand(peer->iffval, len * 8, -1, 1); /* r */
- BN_mod(peer->iffval, peer->iffval, dsa->p, bctx);
- BN_CTX_free(bctx);
- /*
- * Sign and send to Bob. The filestamp is from the local file.
- */
- tstamp = crypto_time();
- memset(vp, 0, sizeof(struct value));
- vp->tstamp = htonl(tstamp);
- vp->fstamp = htonl(peer->fstamp);
- vp->vallen = htonl(len);
- vp->ptr = emalloc(len);
- BN_bn2bin(peer->iffval, vp->ptr);
- vp->siglen = 0;
- if (tstamp == 0)
- return (XEVNT_OK);
- if (tstamp < cinfo->first || tstamp > cinfo->last)
- return (XEVNT_PER);
- vp->sig = emalloc(sign_siglen);
- EVP_SignInit(&ctx, sign_digest);
- EVP_SignUpdate(&ctx, (u_char *)&vp->tstamp, 12);
- EVP_SignUpdate(&ctx, vp->ptr, len);
- if (EVP_SignFinal(&ctx, vp->sig, &len, sign_pkey))
- vp->siglen = htonl(len);
- return (XEVNT_OK);
- }
- /*
- * crypto_bob3 - construct Bob's response to Alice's challenge
- *
- * Returns
- * XEVNT_OK success
- * XEVNT_ERR protocol error
- * XEVNT_PER host certificate expired
- */
- static int
- crypto_bob3(
- struct exten *ep, /* extension pointer */
- struct value *vp /* value pointer */
- )
- {
- DSA *dsa; /* MV parameters */
- DSA *sdsa; /* DSA signature context fake */
- BN_CTX *bctx; /* BIGNUM context */
- EVP_MD_CTX ctx; /* signature context */
- tstamp_t tstamp; /* NTP timestamp */
- BIGNUM *r, *k, *u;
- u_char *ptr;
- u_int len;
- /*
- * If the MV parameters are not valid, something awful
- * happened or we are being tormented.
- */
- if (mvpar_pkey == NULL) {
- msyslog(LOG_INFO, "crypto_bob3: scheme unavailable");
- return (XEVNT_ID);
- }
- dsa = mvpar_pkey->pkey.dsa;
- /*
- * Extract r from the challenge.
- */
- len = ntohl(ep->vallen);
- if ((r = BN_bin2bn((u_char *)ep->pkt, len, NULL)) == NULL) {
- msyslog(LOG_ERR, "crypto_bob3 %s\n",
- ERR_error_string(ERR_get_error(), NULL));
- return (XEVNT_ERR);
- }
- /*
- * Bob rolls random k (0 < k < q), making sure it is not a
- * factor of q. He then computes y = A^k r and sends (hash(y),
- * gbar^k, ghat^k) to Alice.
- */
- bctx = BN_CTX_new(); k = BN_new(); u = BN_new();
- sdsa = DSA_new();
- sdsa->p = BN_new(); sdsa->q = BN_new(); sdsa->g = BN_new();
- while (1) {
- BN_rand(k, BN_num_bits(dsa->q), 0, 0);
- BN_mod(k, k, dsa->q, bctx);
- BN_gcd(u, k, dsa->q, bctx);
- if (BN_is_one(u))
- break;
- }
- BN_mod_exp(u, dsa->g, k, dsa->p, bctx); /* A r */
- BN_mod_mul(u, u, r, dsa->p, bctx);
- bighash(u, sdsa->p);
- BN_mod_exp(sdsa->q, dsa->priv_key, k, dsa->p, bctx); /* gbar */
- BN_mod_exp(sdsa->g, dsa->pub_key, k, dsa->p, bctx); /* ghat */
- BN_CTX_free(bctx); BN_free(k); BN_free(r); BN_free(u);
- /*
- * Encode the values in ASN.1 and sign.
- */
- tstamp = crypto_time();
- memset(vp, 0, sizeof(struct value));
- vp->tstamp = htonl(tstamp);
- vp->fstamp = htonl(mv_fstamp);
- len = i2d_DSAparams(sdsa, NULL);
- if (len <= 0) {
- msyslog(LOG_ERR, "crypto_bob3 %s\n",
- ERR_error_string(ERR_get_error(), NULL));
- DSA_free(sdsa);
- return (XEVNT_ERR);
- }
- vp->vallen = htonl(len);
- ptr = emalloc(len);
- vp->ptr = ptr;
- i2d_DSAparams(sdsa, &ptr);
- DSA_free(sdsa);
- vp->siglen = 0;
- if (tstamp == 0)
- return (XEVNT_OK);
- if (tstamp < cinfo->first || tstamp > cinfo->last)
- return (XEVNT_PER);
- vp->sig = emalloc(sign_siglen);
- EVP_SignInit(&ctx, sign_digest);
- EVP_SignUpdate(&ctx, (u_char *)&vp->tstamp, 12);
- EVP_SignUpdate(&ctx, vp->ptr, len);
- if (EVP_SignFinal(&ctx, vp->sig, &len, sign_pkey))
- vp->siglen = htonl(len);
- return (XEVNT_OK);
- }
- /*
- * crypto_mv - verify Bob's response to Alice's challenge
- *
- * Returns
- * XEVNT_OK success
- * XEVNT_PUB bad or missing public key
- * XEVNT_ID bad or missing group key
- * XEVNT_ERR protocol error
- * XEVNT_FSP bad filestamp
- */
- int
- crypto_mv(
- struct exten *ep, /* extension pointer */
- struct peer *peer /* peer structure pointer */
- )
- {
- DSA *dsa; /* MV parameters */
- DSA *sdsa; /* DSA parameters */
- BN_CTX *bctx; /* BIGNUM context */
- BIGNUM *k, *u, *v;
- u_int len;
- const u_char *ptr;
- int temp;
- /*
- * If the MV parameters are not valid or no challenge was sent,
- * something awful happened or we are being tormented.
- */
- if (peer->ident_pkey == NULL) {
- msyslog(LOG_INFO, "crypto_mv: scheme unavailable");
- return (XEVNT_ID);
- }
- if (ntohl(ep->fstamp) != peer->fstamp) {
- msyslog(LOG_INFO, "crypto_mv: invalid filestamp %u",
- ntohl(ep->fstamp));
- return (XEVNT_FSP);
- }
- if ((dsa = peer->ident_pkey->pkey.dsa) == NULL) {
- msyslog(LOG_INFO, "crypto_mv: defective key");
- return (XEVNT_PUB);
- }
- if (peer->iffval == NULL) {
- msyslog(LOG_INFO, "crypto_mv: missing challenge");
- return (XEVNT_ID);
- }
- /*
- * Extract the (hash(y), gbar, ghat) values from the response.
- */
- bctx = BN_CTX_new(); k = BN_new(); u = BN_new(); v = BN_new();
- len = ntohl(ep->vallen);
- ptr = (const u_char *)ep->pkt;
- if ((sdsa = d2i_DSAparams(NULL, &ptr, len)) == NULL) {
- msyslog(LOG_ERR, "crypto_mv %s\n",
- ERR_error_string(ERR_get_error(), NULL));
- return (XEVNT_ERR);
- }
- /*
- * Compute (gbar^xhat ghat^xbar)^-1 mod p.
- */
- BN_mod_exp(u, sdsa->q, dsa->pub_key, dsa->p, bctx);
- BN_mod_exp(v, sdsa->g, dsa->priv_key, dsa->p, bctx);
- BN_mod_mul(u, u, v, dsa->p, bctx);
- BN_mod_inverse(u, u, dsa->p, bctx);
- BN_mod_mul(v, u, peer->iffval, dsa->p, bctx);
- /*
- * The result should match the hash of r mod p.
- */
- bighash(v, v);
- temp = BN_cmp(v, sdsa->p);
- BN_CTX_free(bctx); BN_free(k); BN_free(u); BN_free(v);
- BN_free(peer->iffval);
- peer->iffval = NULL;
- DSA_free(sdsa);
- if (temp == 0)
- return (XEVNT_OK);
- else
- return (XEVNT_ID);
- }
- /*
- ***********************************************************************
- * *
- * The following routines are used to manipulate certificates *
- * *
- ***********************************************************************
- */
- /*
- * cert_parse - parse x509 certificate and create info/value structures.
- *
- * The server certificate includes the version number, issuer name,
- * subject name, public key and valid date interval. If the issuer name
- * is the same as the subject name, the certificate is self signed and
- * valid only if the server is configured as trustable. If the names are
- * different, another issuer has signed the server certificate and
- * vouched for it. In this case the server certificate is valid if
- * verified by the issuer public key.
- *
- * Returns certificate info/value pointer if valid, NULL if not.
- */
- struct cert_info * /* certificate information structure */
- cert_parse(
- u_char *asn1cert, /* X509 certificate */
- u_int len, /* certificate length */
- tstamp_t fstamp /* filestamp */
- )
- {
- X509 *cert; /* X509 certificate */
- X509_EXTENSION *ext; /* X509v3 extension */
- struct cert_info *ret; /* certificate info/value */
- BIO *bp;
- X509V3_EXT_METHOD *method;
- char pathbuf[MAXFILENAME];
- u_char *uptr;
- char *ptr;
- int temp, cnt, i;
- /*
- * Decode ASN.1 objects and construct certificate structure.
- */
- uptr = asn1cert;
- if ((cert = d2i_X509(NULL, &uptr, len)) == NULL) {
- msyslog(LOG_ERR, "cert_parse %s\n",
- ERR_error_string(ERR_get_error(), NULL));
- return (NULL);
- }
- /*
- * Extract version, subject name and public key.
- */
- ret = emalloc(sizeof(struct cert_info));
- memset(ret, 0, sizeof(struct cert_info));
- if ((ret->pkey = X509_get_pubkey(cert)) == NULL) {
- msyslog(LOG_ERR, "cert_parse %s\n",
- ERR_error_string(ERR_get_error(), NULL));
- cert_free(ret);
- X509_free(cert);
- return (NULL);
- }
- ret->version = X509_get_version(cert);
- X509_NAME_oneline(X509_get_subject_name(cert), pathbuf,
- MAXFILENAME - 1);
- ptr = strstr(pathbuf, "CN=");
- if (ptr == NULL) {
- msyslog(LOG_INFO, "cert_parse: invalid subject %s",
- pathbuf);
- cert_free(ret);
- X509_free(cert);
- return (NULL);
- }
- ret->subject = emalloc(strlen(ptr) + 1);
- strcpy(ret->subject, ptr + 3);
- /*
- * Extract remaining objects. Note that the NTP serial number is
- * the NTP seconds at the time of signing, but this might not be
- * the case for other authority. We don't bother to check the
- * objects at this time, since the real crunch can happen only
- * when the time is valid but not yet certificated.
- */
- ret->nid = OBJ_obj2nid(cert->cert_info->signature->algorithm);
- ret->digest = (const EVP_MD *)EVP_get_digestbynid(ret->nid);
- ret->serial =
- (u_long)ASN1_INTEGER_get(X509_get_serialNumber(cert));
- X509_NAME_oneline(X509_get_issuer_name(cert), pathbuf,
- MAXFILENAME);
- if ((ptr = strstr(pathbuf, "CN=")) == NULL) {
- msyslog(LOG_INFO, "cert_parse: invalid issuer %s",
- pathbuf);
- cert_free(ret);
- X509_free(cert);
- return (NULL);
- }
- ret->issuer = emalloc(strlen(ptr) + 1);
- strcpy(ret->issuer, ptr + 3);
- ret->first = asn2ntp(X509_get_notBefore(cert));
- ret->last = asn2ntp(X509_get_notAfter(cert));
- /*
- * Extract extension fields. These are ad hoc ripoffs of
- * currently assigned functions and will certainly be changed
- * before prime time.
- */
- cnt = X509_get_ext_count(cert);
- for (i = 0; i < cnt; i++) {
- ext = X509_get_ext(cert, i);
- method = X509V3_EXT_get(ext);
- temp = OBJ_obj2nid(ext->object);
- switch (temp) {
- /*
- * If a key_usage field is present, we decode whether
- * this is a trusted or private certificate. This is
- * dorky; all we want is to compare NIDs, but OpenSSL
- * insists on BIO text strings.
- */
- case NID_ext_key_usage:
- bp = BIO_new(BIO_s_mem());
- X509V3_EXT_print(bp, ext, 0, 0);
- BIO_gets(bp, pathbuf, MAXFILENAME);
- BIO_free(bp);
- #if DEBUG
- if (debug)
- printf("cert_parse: %s: %s\n",
- OBJ_nid2ln(temp), pathbuf);
- #endif
- if (strcmp(pathbuf, "Trust Root") == 0)
- ret->flags |= CERT_TRUST;
- else if (strcmp(pathbuf, "Private") == 0)
- ret->flags |= CERT_PRIV;
- break;
- /*
- * If a NID_subject_key_identifier field is present, it
- * contains the GQ public key.
- */
- case NID_subject_key_identifier:
- ret->grplen = ext->value->length - 2;
- ret->grpkey = emalloc(ret->grplen);
- memcpy(ret->grpkey, &ext->value->data[2],
- ret->grplen);
- break;
- }
- }
- /*
- * If certificate is self signed, verify signature.
- */
- if (strcmp(ret->subject, ret->issuer) == 0) {
- if (!X509_verify(cert, ret->pkey)) {
- msyslog(LOG_INFO,
- "cert_parse: signature not verified %s",
- pathbuf);
- cert_free(ret);
- X509_free(cert);
- return (NULL);
- }
- }
- /*
- * Verify certificate valid times. Note that certificates cannot
- * be retroactive.
- */
- if (ret->first > ret->last || ret->first < fstamp) {
- msyslog(LOG_INFO,
- "cert_parse: invalid certificate %s first %u last %u fstamp %u",
- ret->subject, ret->first, ret->last, fstamp);
- cert_free(ret);
- X509_free(cert);
- return (NULL);
- }
- /*
- * Build the value structure to sign and send later.
- */
- ret->cert.fstamp = htonl(fstamp);
- ret->cert.vallen = htonl(len);
- ret->cert.ptr = emalloc(len);
- memcpy(ret->cert.ptr, asn1cert, len);
- #ifdef DEBUG
- if (debug > 1)
- X509_print_fp(stdout, cert);
- #endif
- X509_free(cert);
- return (ret);
- }
- /*
- * cert_sign - sign x509 certificate equest and update value structure.
- *
- * The certificate request includes a copy of the host certificate,
- * which includes the version number, subject name and public key of the
- * host. The resulting certificate includes these values plus the
- * serial number, issuer name and valid interval of the server. The
- * valid interval extends from the current time to the same time one
- * year hence. This may extend the life of the signed certificate beyond
- * that of the signer certificate.
- *
- * It is convenient to use the NTP seconds of the current time as the
- * serial number. In the value structure the timestamp is the current
- * time and the filestamp is taken from the extension field. Note this
- * routine is called only when the client clock is synchronized to a
- * proventic source, so timestamp comparisons are valid.
- *
- * The host certificate is valid from the time it was generated for a
- * period of one year. A signed certificate is valid from the time of
- * signature for a period of one year, but only the host certificate (or
- * sign certificate if used) is actually used to encrypt and decrypt
- * signatures. The signature trail is built from the client via the
- * intermediate servers to the trusted server. Each signature on the
- * trail must be valid at the time of signature, but it could happen
- * that a signer certificate expire before the signed certificate, which
- * remains valid until its expiration.
- *
- * Returns
- * XEVNT_OK success
- * XEVNT_PUB bad or missing public key
- * XEVNT_CRT bad or missing certificate
- * XEVNT_VFY certificate not verified
- * XEVNT_PER host certificate expired
- */
- static int
- cert_sign(
- struct exten *ep, /* extension field pointer */
- struct value *vp /* value pointer */
- )
- {
- X509 *req; /* X509 certificate request */
- X509 *cert; /* X509 certificate */
- X509_EXTENSION *ext; /* certificate extension */
- ASN1_INTEGER *serial; /* serial number */
- X509_NAME *subj; /* distinguished (common) name */
- EVP_PKEY *pkey; /* public key */
- EVP_MD_CTX ctx; /* message digest context */
- tstamp_t tstamp; /* NTP timestamp */
- u_int len;
- u_char *ptr;
- int i, temp;
- /*
- * Decode ASN.1 objects and construct certificate structure.
- * Make sure the system clock is synchronized to a proventic
- * source.
- */
- tstamp = crypto_time();
- if (tstamp == 0)
- return (XEVNT_TSP);
- if (tstamp < cinfo->first || tstamp > cinfo->last)
- return (XEVNT_PER);
- ptr = (u_char *)ep->pkt;
- if ((req = d2i_X509(NULL, &ptr, ntohl(ep->vallen))) == NULL) {
- msyslog(LOG_ERR, "cert_sign %s\n",
- ERR_error_string(ERR_get_error(), NULL));
- return (XEVNT_CRT);
- }
- /*
- * Extract public key and check for errors.
- */
- if ((pkey = X509_get_pubkey(req)) == NULL) {
- msyslog(LOG_ERR, "cert_sign %s\n",
- ERR_error_string(ERR_get_error(), NULL));
- X509_free(req);
- return (XEVNT_PUB);
- }
- /*
- * Generate X509 certificate signed by this server. For this
- * purpose the issuer name is the server name. Also copy any
- * extensions that might be present.
- */
- cert = X509_new();
- X509_set_version(cert, X509_get_version(req));
- serial = ASN1_INTEGER_new();
- ASN1_INTEGER_set(serial, tstamp);
- X509_set_serialNumber(cert, serial);
- X509_gmtime_adj(X509_get_notBefore(cert), 0L);
- X509_gmtime_adj(X509_get_notAfter(cert), YEAR);
- subj = X509_get_issuer_name(cert);
- X509_NAME_add_entry_by_txt(subj, "commonName", MBSTRING_ASC,
- (u_char *)sys_hostname, strlen(sys_hostname), -1, 0);
- subj = X509_get_subject_name(req);
- X509_set_subject_name(cert, subj);
- X509_set_pubkey(cert, pkey);
- ext = X509_get_ext(req, 0);
- temp = X509_get_ext_count(req);
- for (i = 0; i < temp; i++) {
- ext = X509_get_ext(req, i);
- X509_add_ext(cert, ext, -1);
- }
- X509_free(req);
- /*
- * Sign and verify the certificate.
- */
- X509_sign(cert, sign_pkey, sign_digest);
- if (!X509_verify(cert, sign_pkey)) {
- printf("cert_sign\n%s\n",
- ERR_error_string(ERR_get_error(), NULL));
- X509_free(cert);
- return (XEVNT_VFY);
- }
- len = i2d_X509(cert, NULL);
- /*
- * Build and sign the value structure. We have to sign it here,
- * since the response has to be returned right away. This is a
- * clogging hazard.
- */
- memset(vp, 0, sizeof(struct value));
- vp->tstamp = htonl(tstamp);
- vp->fstamp = ep->fstamp;
- vp->vallen = htonl(len);
- vp->ptr = emalloc(len);
- ptr = vp->ptr;
- i2d_X509(cert, &ptr);
- vp->siglen = 0;
- vp->sig = emalloc(sign_siglen);
- EVP_SignInit(&ctx, sign_digest);
- EVP_SignUpdate(&ctx, (u_char *)vp, 12);
- EVP_SignUpdate(&ctx, vp->ptr, len);
- if (EVP_SignFinal(&ctx, vp->sig, &len, sign_pkey))
- vp->siglen = htonl(len);
- #ifdef DEBUG
- if (debug > 1)
- X509_print_fp(stdout, cert);
- #endif
- X509_free(cert);
- return (XEVNT_OK);
- }
- /*
- * cert_valid - verify certificate with given public key
- *
- * This is pretty ugly, as the certificate has to be verified in the
- * OpenSSL X509 structure, not in the DER format in the info/value
- * structure.
- *
- * Returns
- * XEVNT_OK success
- * XEVNT_VFY certificate not verified
- */
- int
- cert_valid(
- struct cert_info *cinf, /* certificate information structure */
- EVP_PKEY *pkey /* public key */
- )
- {
- X509 *cert; /* X509 certificate */
- u_char *ptr;
- if (cinf->flags & CERT_SIGN)
- return (XEVNT_OK);
- ptr = (u_char *)cinf->cert.ptr;
- cert = d2i_X509(NULL, &ptr, ntohl(cinf->cert.vallen));
- if (cert == NULL || !X509_verify(cert, pkey))
- return (XEVNT_VFY);
- X509_free(cert);
- return (XEVNT_OK);
- }
- /*
- * cert - install certificate in certificate list
- *
- * This routine encodes an extension field into a certificate info/value
- * structure. It searches the certificate list for duplicates and
- * expunges whichever is older. It then searches the list for other
- * certificates that might be verified by this latest one. Finally, it
- * inserts this certificate first on the list.
- *
- * Returns
- * XEVNT_OK success
- * XEVNT_FSP bad or missing filestamp
- * XEVNT_CRT bad or missing certificate
- */
- int
- cert_install(
- struct exten *ep, /* cert info/value */
- struct peer *peer /* peer structure */
- )
- {
- struct cert_info *cp, *xp, *yp, **zp;
- /*
- * Parse and validate the signed certificate. If valid,
- * construct the info/value structure; otherwise, scamper home.
- */
- if ((cp = cert_parse((u_char *)ep->pkt, ntohl(ep->vallen),
- ntohl(ep->fstamp))) == NULL)
- return (XEVNT_CRT);
- /*
- * Scan certificate list looking for another certificate with
- * the same subject and issuer. If another is found with the
- * same or older filestamp, unlink it and return the goodies to
- * the heap. If another is found with a later filestamp, discard
- * the new one and leave the building.
- *
- * Make a note to study this issue again. An earlier certificate
- * with a long lifetime might be overtaken by a later
- * certificate with a short lifetime, thus invalidating the
- * earlier signature. However, we gotta find a way to leak old
- * stuff from the cache, so we do it anyway.
- */
- yp = cp;
- zp = &cinfo;
- for (xp = cinfo; xp != NULL; xp = xp->link) {
- if (strcmp(cp->subject, xp->subject) == 0 &&
- strcmp(cp->issuer, xp->issuer) == 0) {
- if (ntohl(cp->cert.fstamp) <=
- ntohl(xp->cert.fstamp)) {
- *zp = xp->link;;
- cert_free(xp);
- } else {
- cert_free(cp);
- return (XEVNT_FSP);
- }
- break;
- }
- zp = &xp->link;
- }
- yp->link = cinfo;
- cinfo = yp;
- /*
- * Scan the certificate list to see if Y is signed by X. This is
- * independent of order.
- */
- for (yp = cinfo; yp != NULL; yp = yp->link) {
- for (xp = cinfo; xp != NULL; xp = xp->link) {
- /*
- * If the issuer of certificate Y matches the
- * subject of certificate X, verify the
- * signature of Y using the public key of X. If
- * so, X signs Y.
- */
- if (strcmp(yp->issuer, xp->subject) != 0 ||
- xp->flags & CERT_ERROR)
- continue;
- if (cert_valid(yp, xp->pkey) != XEVNT_OK) {
- yp->flags |= CERT_ERROR;
- continue;
- }
- /*
- * The signature Y is valid only if it begins
- * during the lifetime of X; however, it is not
- * necessarily an error, since some other
- * certificate might sign Y.
- */
- if (yp->first < xp->first || yp->first >
- xp->last)
- continue;
- yp->flags |= CERT_SIGN;
- /*
- * If X is trusted, then Y is trusted. Note that
- * we might stumble over a self-signed
- * certificate that is not trusted, at least
- * temporarily. This can happen when a dude
- * first comes up, but has not synchronized the
- * clock and had its certificate signed by its
- * server. In case of broken certificate trail,
- * this might result in a loop that could
- * persist until timeout.
- */
- if (!(xp->flags & (CERT_TRUST | CERT_VALID)))
- continue;
- yp->flags |= CERT_VALID;
- /*
- * If subject Y matches the server subject name,
- * then Y has completed the certificate trail.
- * Save the group key and light the valid bit.
- */
- if (strcmp(yp->subject, peer->subject) != 0)
- continue;
- if (yp->grpkey != NULL) {
- if (peer->grpkey != NULL)
- BN_free(peer->grpkey);
- peer->grpkey = BN_bin2bn(yp->grpkey,
- yp->grplen, NULL);
- }
- peer->crypto |= CRYPTO_FLAG_VALID;
- /*
- * If the server has an an identity scheme,
- * fetch the identity credentials. If not, the
- * identity is verified only by the trusted
- * certificate. The next signature will set the
- * server proventic.
- */
- if (peer->crypto & (CRYPTO_FLAG_GQ |
- CRYPTO_FLAG_IFF | CRYPTO_FLAG_MV))
- continue;
- peer->crypto |= CRYPTO_FLAG_VRFY;
- }
- }
- /*
- * That was awesome. Now update the timestamps and signatures.
- */
- crypto_update();
- return (XEVNT_OK);
- }
- /*
- * cert_free - free certificate information structure
- */
- void
- cert_free(
- struct cert_info *cinf /* certificate info/value structure */
- )
- {
- if (cinf->pkey != NULL)
- EVP_PKEY_free(cinf->pkey);
- if (cinf->subject != NULL)
- free(cinf->subject);
- if (cinf->issuer != NULL)
- free(cinf->issuer);
- if (cinf->grpkey != NULL)
- free(cinf->grpkey);
- value_free(&cinf->cert);
- free(cinf);
- }
- /*
- ***********************************************************************
- * *
- * The following routines are used only at initialization time *
- * *
- ***********************************************************************
- */
- /*
- * crypto_key - load cryptographic parameters and keys from files
- *
- * This routine loads a PEM-encoded public/private key pair and extracts
- * the filestamp from the file name.
- *
- * Returns public key pointer if valid, NULL if not. Side effect updates
- * the filestamp if valid.
- */
- static EVP_PKEY *
- crypto_key(
- char *cp, /* file name */
- tstamp_t *fstamp /* filestamp */
- )
- {
- FILE *str; /* file handle */
- EVP_PKEY *pkey = NULL; /* public/private key */
- char filename[MAXFILENAME]; /* name of key file */
- char linkname[MAXFILENAME]; /* filestamp buffer) */
- char statstr[NTP_MAXSTRLEN]; /* statistics for filegen */
- char *ptr;
- /*
- * Open the key file. If the first character of the file name is
- * not '/', prepend the keys directory string. If something goes
- * wrong, abandon ship.
- */
- if (*cp == '/')
- strcpy(filename, cp);
- else
- snprintf(filename, MAXFILENAME, "%s/%s", keysdir, cp);
- str = fopen(filename, "r");
- if (str == NULL)
- return (NULL);
- /*
- * Read the filestamp, which is contained in the first line.
- */
- if ((ptr = fgets(linkname, MAXFILENAME, str)) == NULL) {
- msyslog(LOG_ERR, "crypto_key: no data %s\n",
- filename);
- (void)fclose(str);
- return (NULL);
- }
- if ((ptr = strrchr(ptr, '.')) == NULL) {
- msyslog(LOG_ERR, "crypto_key: no filestamp %s\n",
- filename);
- (void)fclose(str);
- return (NULL);
- }
- if (sscanf(++ptr, "%u", fstamp) != 1) {
- msyslog(LOG_ERR, "crypto_key: invalid timestamp %s\n",
- filename);
- (void)fclose(str);
- return (NULL);
- }
- /*
- * Read and decrypt PEM-encoded private key.
- */
- pkey = PEM_read_PrivateKey(str, NULL, NULL, passwd);
- fclose(str);
- if (pkey == NULL) {
- msyslog(LOG_ERR, "crypto_key %s\n",
- ERR_error_string(ERR_get_error(), NULL));
- return (NULL);
- }
- /*
- * Leave tracks in the cryptostats.
- */
- if ((ptr = strrchr(linkname, '\n')) != NULL)
- *ptr = '\0';
- snprintf(statstr, NTP_MAXSTRLEN, "%s mod %d", &linkname[2],
- EVP_PKEY_size(pkey) * 8);
- record_crypto_stats(NULL, statstr);
- #ifdef DEBUG
- if (debug)
- printf("crypto_key: %s\n", statstr);
- if (debug > 1) {
- if (pkey->type == EVP_PKEY_DSA)
- DSA_print_fp(stdout, pkey->pkey.dsa, 0);
- else
- RSA_print_fp(stdout, pkey->pkey.rsa, 0);
- }
- #endif
- return (pkey);
- }
- /*
- * crypto_cert - load certificate from file
- *
- * This routine loads a X.509 RSA or DSA certificate from a file and
- * constructs a info/cert value structure for this machine. The
- * structure includes a filestamp extracted from the file name. Later
- * the certificate can be sent to another machine by request.
- *
- * Returns certificate info/value pointer if valid, NULL if not.
- */
- static struct cert_info * /* certificate information */
- crypto_cert(
- char *cp /* file name */
- )
- {
- struct cert_info *ret; /* certificate information */
- FILE *str; /* file handle */
- char filename[MAXFILENAME]; /* name of certificate file */
- char linkname[MAXFILENAME]; /* filestamp buffer */
- char statstr[NTP_MAXSTRLEN]; /* statistics for filegen */
- tstamp_t fstamp; /* filestamp */
- long len;
- char *ptr;
- char *name, *header;
- u_char *data;
- /*
- * Open the certificate file. If the first character of the file
- * name is not '/', prepend the keys directory string. If
- * something goes wrong, abandon ship.
- */
- if (*cp == '/')
- strcpy(filename, cp);
- else
- snprintf(filename, MAXFILENAME, "%s/%s", keysdir, cp);
- str = fopen(filename, "r");
- if (str == NULL)
- return (NULL);
- /*
- * Read the filestamp, which is contained in the first line.
- */
- if ((ptr = fgets(linkname, MAXFILENAME, str)) == NULL) {
- msyslog(LOG_ERR, "crypto_cert: no data %s\n",
- filename);
- (void)fclose(str);
- return (NULL);
- }
- if ((ptr = strrchr(ptr, '.')) == NULL) {
- msyslog(LOG_ERR, "crypto_cert: no filestamp %s\n",
- filename);
- (void)fclose(str);
- return (NULL);
- }
- if (sscanf(++ptr, "%u", &fstamp) != 1) {
- msyslog(LOG_ERR, "crypto_cert: invalid filestamp %s\n",
- filename);
- (void)fclose(str);
- return (NULL);
- }
- /*
- * Read PEM-encoded certificate and install.
- */
- if (!PEM_read(str, &name, &header, &data, &len)) {
- msyslog(LOG_ERR, "crypto_cert %s\n",
- ERR_error_string(ERR_get_error(), NULL));
- (void)fclose(str);
- return (NULL);
- }
- free(header);
- if (strcmp(name, "CERTIFICATE") !=0) {
- msyslog(LOG_INFO, "crypto_cert: wrong PEM type %s",
- name);
- free(name);
- free(data);
- (void)fclose(str);
- return (NULL);
- }
- free(name);
- /*
- * Parse certificate and generate info/value structure.
- */
- ret = cert_parse(data, len, fstamp);
- free(data);
- (void)fclose(str);
- if (ret == NULL)
- return (NULL);
- if ((ptr = strrchr(linkname, '\n')) != NULL)
- *ptr = '\0';
- snprintf(statstr, NTP_MAXSTRLEN,
- "%s 0x%x len %lu", &linkname[2], ret->flags, len);
- record_crypto_stats(NULL, statstr);
- #ifdef DEBUG
- if (debug)
- printf("crypto_cert: %s\n", statstr);
- #endif
- return (ret);
- }
- /*
- * crypto_tai - load leapseconds table from file
- *
- * This routine loads the ERTS leapsecond file in NIST text format,
- * converts to a value structure and extracts a filestamp from the file
- * name. The data are used to establish the TAI offset from UTC, which
- * is provided to the kernel if supported. Later the data can be sent to
- * another machine on request.
- */
- static void
- crypto_tai(
- char *cp /* file name */
- )
- {
- FILE *str; /* file handle */
- char buf[NTP_MAXSTRLEN]; /* file line buffer */
- u_int32 leapsec[MAX_LEAP]; /* NTP time at leaps */
- int offset; /* offset at leap (s) */
- char filename[MAXFILENAME]; /* name of leapseconds file */
- char linkname[MAXFILENAME]; /* file link (for filestamp) */
- char statstr[NTP_MAXSTRLEN]; /* statistics for filegen */
- tstamp_t fstamp; /* filestamp */
- u_int len;
- u_int32 *ptr;
- char *dp;
- int rval, i, j;
- /*
- * Open the file and discard comment lines. If the first
- * character of the file name is not '/', prepend the keys
- * directory string. If the file is not found, not to worry; it
- * can be retrieved over the net. But, if it is found with
- * errors, we crash and burn.
- */
- if (*cp == '/')
- strcpy(filename, cp);
- else
- snprintf(filename, MAXFILENAME, "%s/%s", keysdir, cp);
- if ((str = fopen(filename, "r")) == NULL)
- return;
- /*
- * Extract filestamp if present.
- */
- rval = readlink(filename, linkname, MAXFILENAME - 1);
- if (rval > 0) {
- linkname[rval] = '\0';
- dp = strrchr(linkname, '.');
- } else {
- dp = strrchr(filename, '.');
- }
- if (dp != NULL)
- sscanf(++dp, "%u", &fstamp);
- else
- fstamp = 0;
- tai_leap.fstamp = htonl(fstamp);
- /*
- * We are rather paranoid here, since an intruder might cause a
- * coredump by infiltrating naughty values. Empty lines and
- * comments are ignored. Other lines must begin with two
- * integers followed by junk or comments. The first integer is
- * the NTP seconds of leap insertion, the second is the offset
- * of TAI relative to UTC after that insertion. The second word
- * must equal the initial insertion of ten seconds on 1 January
- * 1972 plus one second for each succeeding insertion.
- */
- i = 0;
- while (i < MAX_LEAP) {
- dp = fgets(buf, NTP_MAXSTRLEN - 1, str);
- if (dp == NULL)
- break;
- if (strlen(buf) < 1)
- continue;
- if (*buf == '#')
- continue;
- if (sscanf(buf, "%u %d", &leapsec[i], &offset) != 2)
- continue;
- if (i != offset - TAI_1972)
- break;
- i++;
- }
- fclose(str);
- if (dp != NULL) {
- msyslog(LOG_INFO,
- "crypto_tai: leapseconds file %s error %d", cp,
- rval);
- exit (-1);
- }
- /*
- * The extension field table entries consists of the NTP seconds
- * of leap insertion in network byte order.
- */
- len = i * sizeof(u_int32);
- tai_leap.vallen = htonl(len);
- ptr = emalloc(len);
- tai_leap.ptr = (u_char *)ptr;
- for (j = 0; j < i; j++)
- *ptr++ = htonl(leapsec[j]);
- crypto_flags |= CRYPTO_FLAG_TAI;
- snprintf(statstr, NTP_MAXSTRLEN, "%s fs %u leap %u len %u", cp, fstamp,
- leapsec[--j], len);
- record_crypto_stats(NULL, statstr);
- #ifdef DEBUG
- if (debug)
- printf("crypto_tai: %s\n", statstr);
- #endif
- }
- /*
- * crypto_setup - load keys, certificate and leapseconds table
- *
- * This routine loads the public/private host key and certificate. If
- * available, it loads the public/private sign key, which defaults to
- * the host key, and leapseconds table. The host key must be RSA, but
- * the sign key can be either RSA or DSA. In either case, the public key
- * on the certificate must agree with the sign key.
- */
- void
- crypto_setup(void)
- {
- EVP_PKEY *pkey; /* private/public key pair */
- char filename[MAXFILENAME]; /* file name buffer */
- l_fp seed; /* crypto PRNG seed as NTP timestamp */
- tstamp_t fstamp; /* filestamp */
- tstamp_t sstamp; /* sign filestamp */
- u_int len, bytes;
- u_char *ptr;
- /*
- * Initialize structures.
- */
- if (!crypto_flags)
- return;
- gethostname(filename, MAXFILENAME);
- bytes = strlen(filename) + 1;
- sys_hostname = emalloc(bytes);
- memcpy(sys_hostname, filename, bytes);
- if (passwd == NULL)
- passwd = sys_hostname;
- memset(&hostval, 0, sizeof(hostval));
- memset(&pubkey, 0, sizeof(pubkey));
- memset(&tai_leap, 0, sizeof(tai_leap));
- /*
- * Load required random seed file and seed the random number
- * generator. Be default, it is found in the user home
- * directory. The root home directory may be / or /root,
- * depending on the system. Wiggle the contents a bit and write
- * it back so the sequence does not repeat when we next restart.
- */
- ERR_load_crypto_strings();
- if (rand_file == NULL) {
- if ((RAND_file_name(filename, MAXFILENAME)) != NULL) {
- rand_file = emalloc(strlen(filename) + 1);
- strcpy(rand_file, filename);
- }
- } else if (*rand_file != '/') {
- snprintf(filename, MAXFILENAME, "%s/%s", keysdir,
- rand_file);
- free(rand_file);
- rand_file = emalloc(strlen(filename) + 1);
- strcpy(rand_file, filename);
- }
- if (rand_file == NULL) {
- msyslog(LOG_ERR,
- "crypto_setup: random seed file not specified");
- exit (-1);
- }
- if ((bytes = RAND_load_file(rand_file, -1)) == 0) {
- msyslog(LOG_ERR,
- "crypto_setup: random seed file %s not found\n",
- rand_file);
- exit (-1);
- }
- get_systime(&seed);
- RAND_seed(&seed, sizeof(l_fp));
- RAND_write_file(rand_file);
- OpenSSL_add_all_algorithms();
- #ifdef DEBUG
- if (debug)
- printf(
- "crypto_setup: OpenSSL version %lx random seed file %s bytes read %d\n",
- SSLeay(), rand_file, bytes);
- #endif
- /*
- * Load required host key from file "ntpkey_host_<hostname>". It
- * also becomes the default sign key.
- */
- if (host_file == NULL) {
- snprintf(filename, MAXFILENAME, "ntpkey_host_%s",
- sys_hostname);
- host_file = emalloc(strlen(filename) + 1);
- strcpy(host_file, filename);
- }
- pkey = crypto_key(host_file, &fstamp);
- if (pkey == NULL) {
- msyslog(LOG_ERR,
- "crypto_setup: host key file %s not found or corrupt",
- host_file);
- exit (-1);
- }
- host_pkey = pkey;
- sign_pkey = pkey;
- sstamp = fstamp;
- hostval.fstamp = htonl(fstamp);
- if (host_pkey->type != EVP_PKEY_RSA) {
- msyslog(LOG_ERR,
- "crypto_setup: host key is not RSA key type");
- exit (-1);
- }
- hostval.vallen = htonl(strlen(sys_hostname));
- hostval.ptr = (u_char *)sys_hostname;
-
- /*
- * Construct public key extension field for agreement scheme.
- */
- len = i2d_PublicKey(host_pkey, NULL);
- ptr = emalloc(len);
- pubkey.ptr = ptr;
- i2d_PublicKey(host_pkey, &ptr);
- pubkey.vallen = htonl(len);
- pubkey.fstamp = hostval.fstamp;
- /*
- * Load optional sign key from file "ntpkey_sign_<hostname>". If
- * loaded, it becomes the sign key.
- */
- if (sign_file == NULL) {
- snprintf(filename, MAXFILENAME, "ntpkey_sign_%s",
- sys_hostname);
- sign_file = emalloc(strlen(filename) + 1);
- strcpy(sign_file, filename);
- }
- pkey = crypto_key(sign_file, &fstamp);
- if (pkey != NULL) {
- sign_pkey = pkey;
- sstamp = fstamp;
- }
- sign_siglen = EVP_PKEY_size(sign_pkey);
- /*
- * Load optional IFF parameters from file
- * "ntpkey_iff_<hostname>".
- */
- if (iffpar_file == NULL) {
- snprintf(filename, MAXFILENAME, "ntpkey_iff_%s",
- sys_hostname);
- iffpar_file = emalloc(strlen(filename) + 1);
- strcpy(iffpar_file, filename);
- }
- iffpar_pkey = crypto_key(iffpar_file, &if_fstamp);
- if (iffpar_pkey != NULL)
- crypto_flags |= CRYPTO_FLAG_IFF;
- /*
- * Load optional GQ parameters from file "ntpkey_gq_<hostname>".
- */
- if (gqpar_file == NULL) {
- snprintf(filename, MAXFILENAME, "ntpkey_gq_%s",
- sys_hostname);
- gqpar_file = emalloc(strlen(filename) + 1);
- strcpy(gqpar_file, filename);
- }
- gqpar_pkey = crypto_key(gqpar_file, &gq_fstamp);
- if (gqpar_pkey != NULL)
- crypto_flags |= CRYPTO_FLAG_GQ;
- /*
- * Load optional MV parameters from file "ntpkey_mv_<hostname>".
- */
- if (mvpar_file == NULL) {
- snprintf(filename, MAXFILENAME, "ntpkey_mv_%s",
- sys_hostname);
- mvpar_file = emalloc(strlen(filename) + 1);
- strcpy(mvpar_file, filename);
- }
- mvpar_pkey = crypto_key(mvpar_file, &mv_fstamp);
- if (mvpar_pkey != NULL)
- crypto_flags |= CRYPTO_FLAG_MV;
- /*
- * Load required certificate from file "ntpkey_cert_<hostname>".
- */
- if (cert_file == NULL) {
- snprintf(filename, MAXFILENAME, "ntpkey_cert_%s",
- sys_hostname);
- cert_file = emalloc(strlen(filename) + 1);
- strcpy(cert_file, filename);
- }
- if ((cinfo = crypto_cert(cert_file)) == NULL) {
- msyslog(LOG_ERR,
- "certificate file %s not found or corrupt",
- cert_file);
- exit (-1);
- }
- /*
- * The subject name must be the same as the host name, unless
- * the certificate is private, in which case it may have come
- * from another host.
- */
- if (!(cinfo->flags & CERT_PRIV) && strcmp(cinfo->subject,
- sys_hostname) != 0) {
- msyslog(LOG_ERR,
- "crypto_setup: certificate %s not for this host",
- cert_file);
- cert_free(cinfo);
- exit (-1);
- }
- /*
- * It the certificate is trusted, the subject must be the same
- * as the issuer, in other words it must be self signed.
- */
- if (cinfo->flags & CERT_TRUST && strcmp(cinfo->subject,
- cinfo->issuer) != 0) {
- if (cert_valid(cinfo, sign_pkey) != XEVNT_OK) {
- msyslog(LOG_ERR,
- "crypto_setup: certificate %s is trusted, but not self signed.",
- cert_file);
- cert_free(cinfo);
- exit (-1);
- }
- }
- sign_digest = cinfo->digest;
- if (cinfo->flags & CERT_PRIV)
- crypto_flags |= CRYPTO_FLAG_PRIV;
- crypto_flags |= cinfo->nid << 16;
- /*
- * Load optional leapseconds table from file "ntpkey_leap". If
- * the file is missing or defective, the values can later be
- * retrieved from a server.
- */
- if (leap_file == NULL)
- leap_file = "ntpkey_leap";
- crypto_tai(leap_file);
- #ifdef DEBUG
- if (debug)
- printf(
- "crypto_setup: flags 0x%x host %s signature %s\n",
- crypto_flags, sys_hostname, OBJ_nid2ln(cinfo->nid));
- #endif
- }
- /*
- * crypto_config - configure data from crypto configuration command.
- */
- void
- crypto_config(
- int item, /* configuration item */
- char *cp /* file name */
- )
- {
- switch (item) {
- /*
- * Set random seed file name.
- */
- case CRYPTO_CONF_RAND:
- rand_file = emalloc(strlen(cp) + 1);
- strcpy(rand_file, cp);
- break;
- /*
- * Set private key password.
- */
- case CRYPTO_CONF_PW:
- passwd = emalloc(strlen(cp) + 1);
- strcpy(passwd, cp);
- break;
- /*
- * Set host file name.
- */
- case CRYPTO_CONF_PRIV:
- host_file = emalloc(strlen(cp) + 1);
- strcpy(host_file, cp);
- break;
- /*
- * Set sign key file name.
- */
- case CRYPTO_CONF_SIGN:
- sign_file = emalloc(strlen(cp) + 1);
- strcpy(sign_file, cp);
- break;
- /*
- * Set iff parameters file name.
- */
- case CRYPTO_CONF_IFFPAR:
- iffpar_file = emalloc(strlen(cp) + 1);
- strcpy(iffpar_file, cp);
- break;
- /*
- * Set gq parameters file name.
- */
- case CRYPTO_CONF_GQPAR:
- gqpar_file = emalloc(strlen(cp) + 1);
- strcpy(gqpar_file, cp);
- break;
- /*
- * Set mv parameters file name.
- */
- case CRYPTO_CONF_MVPAR:
- mvpar_file = emalloc(strlen(cp) + 1);
- strcpy(mvpar_file, cp);
- break;
- /*
- * Set identity scheme.
- */
- case CRYPTO_CONF_IDENT:
- if (!strcasecmp(cp, "iff"))
- ident_scheme |= CRYPTO_FLAG_IFF;
- else if (!strcasecmp(cp, "gq"))
- ident_scheme |= CRYPTO_FLAG_GQ;
- else if (!strcasecmp(cp, "mv"))
- ident_scheme |= CRYPTO_FLAG_MV;
- break;
- /*
- * Set certificate file name.
- */
- case CRYPTO_CONF_CERT:
- cert_file = emalloc(strlen(cp) + 1);
- strcpy(cert_file, cp);
- break;
- /*
- * Set leapseconds file name.
- */
- case CRYPTO_CONF_LEAP:
- leap_file = emalloc(strlen(cp) + 1);
- strcpy(leap_file, cp);
- break;
- }
- crypto_flags |= CRYPTO_FLAG_ENAB;
- }
- # else
- int ntp_crypto_bs_pubkey;
- # endif /* OPENSSL */