void
test_GenerateAuthenticatedPacket(void)
{
static const int EXPECTED_PKTLEN = LEN_PKT_NOMAC + MAX_MD5_LEN;
struct key testkey;
struct pkt testpkt;
struct timeval xmt;
l_fp expected_xmt, actual_xmt;
char expected_mac[MAX_MD5_LEN];
testkey.next = NULL;
testkey.key_id = 30;
testkey.key_len = 9;
memcpy(testkey.key_seq, "123456789", testkey.key_len);
strlcpy(testkey.typen, "MD5", sizeof(testkey.typen));
testkey.typei = keytype_from_text(testkey.typen, NULL);
GETTIMEOFDAY(&xmt, NULL);
xmt.tv_sec += JAN_1970;
TEST_ASSERT_EQUAL(EXPECTED_PKTLEN,
generate_pkt(&testpkt, &xmt, testkey.key_id, &testkey));
TEST_ASSERT_EQUAL(LEAP_NOTINSYNC, PKT_LEAP(testpkt.li_vn_mode));
TEST_ASSERT_EQUAL(NTP_VERSION, PKT_VERSION(testpkt.li_vn_mode));
TEST_ASSERT_EQUAL(MODE_CLIENT, PKT_MODE(testpkt.li_vn_mode));
TEST_ASSERT_EQUAL(STRATUM_UNSPEC, PKT_TO_STRATUM(testpkt.stratum));
TEST_ASSERT_EQUAL(8, testpkt.ppoll);
TVTOTS(&xmt, &expected_xmt);
NTOHL_FP(&testpkt.xmt, &actual_xmt);
TEST_ASSERT_TRUE(LfpEquality(expected_xmt, actual_xmt));
TEST_ASSERT_EQUAL(testkey.key_id, ntohl(testpkt.exten[0]));
TEST_ASSERT_EQUAL(MAX_MD5_LEN - 4, /* Remove the key_id, only keep the mac. */
make_mac(&testpkt, LEN_PKT_NOMAC, MAX_MD5_LEN-4, &testkey, expected_mac));
TEST_ASSERT_EQUAL_MEMORY(expected_mac, (char*)&testpkt.exten[1], MAX_MD5_LEN -4);
}
TEST_F(mainTest, GenerateUnauthenticatedPacket) {
pkt testpkt;
timeval xmt;
GETTIMEOFDAY(&xmt, NULL);
xmt.tv_sec += JAN_1970;
EXPECT_EQ(LEN_PKT_NOMAC,
generate_pkt(&testpkt, &xmt, 0, NULL));
EXPECT_EQ(LEAP_NOTINSYNC, PKT_LEAP(testpkt.li_vn_mode));
EXPECT_EQ(NTP_VERSION, PKT_VERSION(testpkt.li_vn_mode));
EXPECT_EQ(MODE_CLIENT, PKT_MODE(testpkt.li_vn_mode));
EXPECT_EQ(STRATUM_UNSPEC, PKT_TO_STRATUM(testpkt.stratum));
EXPECT_EQ(8, testpkt.ppoll);
l_fp expected_xmt, actual_xmt;
TVTOTS(&xmt, &expected_xmt);
NTOHL_FP(&testpkt.xmt, &actual_xmt);
EXPECT_TRUE(LfpEquality(expected_xmt, actual_xmt));
}
TEST_F(mainTest, GenerateAuthenticatedPacket) {
key testkey;
testkey.next = NULL;
testkey.key_id = 30;
testkey.key_len = 9;
memcpy(testkey.key_seq, "123456789", testkey.key_len);
memcpy(testkey.type, "MD5", 3);
pkt testpkt;
timeval xmt;
GETTIMEOFDAY(&xmt, NULL);
xmt.tv_sec += JAN_1970;
const int EXPECTED_PKTLEN = LEN_PKT_NOMAC + MAX_MD5_LEN;
EXPECT_EQ(EXPECTED_PKTLEN,
generate_pkt(&testpkt, &xmt, testkey.key_id, &testkey));
EXPECT_EQ(LEAP_NOTINSYNC, PKT_LEAP(testpkt.li_vn_mode));
EXPECT_EQ(NTP_VERSION, PKT_VERSION(testpkt.li_vn_mode));
EXPECT_EQ(MODE_CLIENT, PKT_MODE(testpkt.li_vn_mode));
EXPECT_EQ(STRATUM_UNSPEC, PKT_TO_STRATUM(testpkt.stratum));
EXPECT_EQ(8, testpkt.ppoll);
l_fp expected_xmt, actual_xmt;
TVTOTS(&xmt, &expected_xmt);
NTOHL_FP(&testpkt.xmt, &actual_xmt);
EXPECT_TRUE(LfpEquality(expected_xmt, actual_xmt));
EXPECT_EQ(testkey.key_id, ntohl(testpkt.exten[0]));
char expected_mac[MAX_MD5_LEN];
ASSERT_EQ(MAX_MD5_LEN - 4, // Remove the key_id, only keep the mac.
make_mac((char*)&testpkt, LEN_PKT_NOMAC, MAX_MD5_LEN, &testkey, expected_mac));
EXPECT_TRUE(memcmp(expected_mac, (char*)&testpkt.exten[1], MAX_MD5_LEN -4) == 0);
}
void
test_GenerateUnauthenticatedPacket(void)
{
struct pkt testpkt;
struct timeval xmt;
l_fp expected_xmt, actual_xmt;
GETTIMEOFDAY(&xmt, NULL);
xmt.tv_sec += JAN_1970;
TEST_ASSERT_EQUAL(LEN_PKT_NOMAC,
generate_pkt(&testpkt, &xmt, 0, NULL));
TEST_ASSERT_EQUAL(LEAP_NOTINSYNC, PKT_LEAP(testpkt.li_vn_mode));
TEST_ASSERT_EQUAL(NTP_VERSION, PKT_VERSION(testpkt.li_vn_mode));
TEST_ASSERT_EQUAL(MODE_CLIENT, PKT_MODE(testpkt.li_vn_mode));
TEST_ASSERT_EQUAL(STRATUM_UNSPEC, PKT_TO_STRATUM(testpkt.stratum));
TEST_ASSERT_EQUAL(8, testpkt.ppoll);
TVTOTS(&xmt, &expected_xmt);
NTOHL_FP(&testpkt.xmt, &actual_xmt);
TEST_ASSERT_TRUE(LfpEquality(expected_xmt, actual_xmt));
}
/*
* ntp_monitor - record stats about this packet
*
* Returns supplied restriction flags, with RES_LIMITED and RES_KOD
* cleared unless the packet should not be responded to normally
* (RES_LIMITED) and possibly should trigger a KoD response (RES_KOD).
* The returned flags are saved in the MRU entry, so that it reflects
* whether the last packet from that source triggered rate limiting,
* and if so, possible KoD response. This implies you can not tell
* whether a given address is eligible for rate limiting/KoD from the
* monlist restrict bits, only whether or not the last packet triggered
* such responses. ntpdc -c reslist lets you see whether RES_LIMITED
* or RES_KOD is lit for a particular address before ntp_monitor()'s
* typical dousing.
*/
u_short
ntp_monitor(
struct recvbuf *rbufp,
u_short flags
)
{
l_fp interval_fp;
struct pkt * pkt;
mon_entry * mon;
mon_entry * oldest;
int oldest_age;
u_int hash;
u_short restrict_mask;
u_char mode;
u_char version;
int interval;
int head; /* headway increment */
int leak; /* new headway */
int limit; /* average threshold */
REQUIRE(rbufp != NULL);
if (mon_enabled == MON_OFF)
return ~(RES_LIMITED | RES_KOD) & flags;
pkt = &rbufp->recv_pkt;
hash = MON_HASH(&rbufp->recv_srcadr);
mode = PKT_MODE(pkt->li_vn_mode);
version = PKT_VERSION(pkt->li_vn_mode);
mon = mon_hash[hash];
/*
* We keep track of all traffic for a given IP in one entry,
* otherwise cron'ed ntpdate or similar evades RES_LIMITED.
*/
for (; mon != NULL; mon = mon->hash_next)
if (SOCK_EQ(&mon->rmtadr, &rbufp->recv_srcadr))
break;
if (mon != NULL) {
interval_fp = rbufp->recv_time;
L_SUB(&interval_fp, &mon->last);
/* add one-half second to round up */
L_ADDUF(&interval_fp, 0x80000000);
interval = interval_fp.l_i;
mon->last = rbufp->recv_time;
NSRCPORT(&mon->rmtadr) = NSRCPORT(&rbufp->recv_srcadr);
mon->count++;
restrict_mask = flags;
mon->vn_mode = VN_MODE(version, mode);
/* Shuffle to the head of the MRU list. */
UNLINK_DLIST(mon, mru);
LINK_DLIST(mon_mru_list, mon, mru);
/*
* At this point the most recent arrival is first in the
* MRU list. Decrease the counter by the headway, but
* not less than zero.
*/
mon->leak -= interval;
mon->leak = max(0, mon->leak);
head = 1 << ntp_minpoll;
leak = mon->leak + head;
limit = NTP_SHIFT * head;
DPRINTF(2, ("MRU: interval %d headway %d limit %d\n",
interval, leak, limit));
/*
* If the minimum and average thresholds are not
* exceeded, douse the RES_LIMITED and RES_KOD bits and
* increase the counter by the headway increment. Note
* that we give a 1-s grace for the minimum threshold
* and a 2-s grace for the headway increment. If one or
* both thresholds are exceeded and the old counter is
* less than the average threshold, set the counter to
* the average threshold plus the increment and leave
* the RES_LIMITED and RES_KOD bits lit. Otherwise,
* leave the counter alone and douse the RES_KOD bit.
* This rate-limits the KoDs to no less than the average
* headway.
*/
if (interval + 1 >= ntp_minpkt && leak < limit) {
mon->leak = leak - 2;
restrict_mask &= ~(RES_LIMITED | RES_KOD);
} else if (mon->leak < limit)
mon->leak = limit + head;
else
restrict_mask &= ~RES_KOD;
mon->flags = restrict_mask;
return mon->flags;
}
/*
* If we got here, this is the first we've heard of this
* guy. Get him some memory, either from the free list
* or from the tail of the MRU list.
*
* The following ntp.conf "mru" knobs come into play determining
* the depth (or count) of the MRU list:
* - mru_mindepth ("mru mindepth") is a floor beneath which
* entries are kept without regard to their age. The
* default is 600 which matches the longtime implementation
* limit on the total number of entries.
* - mru_maxage ("mru maxage") is a ceiling on the age in
* seconds of entries. Entries older than this are
* reclaimed once mon_mindepth is exceeded. 64s default.
* Note that entries older than this can easily survive
* as they are reclaimed only as needed.
* - mru_maxdepth ("mru maxdepth") is a hard limit on the
* number of entries.
* - "mru maxmem" sets mru_maxdepth to the number of entries
* which fit in the given number of kilobytes. The default is
* 1024, or 1 megabyte.
* - mru_initalloc ("mru initalloc" sets the count of the
* initial allocation of MRU entries.
* - "mru initmem" sets mru_initalloc in units of kilobytes.
* The default is 4.
* - mru_incalloc ("mru incalloc" sets the number of entries to
* allocate on-demand each time the free list is empty.
* - "mru incmem" sets mru_incalloc in units of kilobytes.
* The default is 4.
* Whichever of "mru maxmem" or "mru maxdepth" occurs last in
* ntp.conf controls. Similarly for "mru initalloc" and "mru
* initmem", and for "mru incalloc" and "mru incmem".
*/
if (mru_entries < mru_mindepth) {
if (NULL == mon_free)
mon_getmoremem();
UNLINK_HEAD_SLIST(mon, mon_free, hash_next);
} else {
oldest = TAIL_DLIST(mon_mru_list, mru);
oldest_age = 0; /* silence uninit warning */
if (oldest != NULL) {
interval_fp = rbufp->recv_time;
L_SUB(&interval_fp, &oldest->last);
/* add one-half second to round up */
L_ADDUF(&interval_fp, 0x80000000);
oldest_age = interval_fp.l_i;
}
/* note -1 is legal for mru_maxage (disables) */
if (oldest != NULL && mru_maxage < oldest_age) {
mon_reclaim_entry(oldest);
mon = oldest;
} else if (mon_free != NULL || mru_alloc <
mru_maxdepth) {
if (NULL == mon_free)
mon_getmoremem();
UNLINK_HEAD_SLIST(mon, mon_free, hash_next);
/* Preempt from the MRU list if old enough. */
} else if (ntp_random() / (2. * FRAC) >
(double)oldest_age / mon_age) {
return ~(RES_LIMITED | RES_KOD) & flags;
} else {
mon_reclaim_entry(oldest);
mon = oldest;
}
}
INSIST(mon != NULL);
/*
* Got one, initialize it
*/
mru_entries++;
mru_peakentries = max(mru_peakentries, mru_entries);
mon->last = rbufp->recv_time;
mon->first = mon->last;
mon->count = 1;
mon->flags = ~(RES_LIMITED | RES_KOD) & flags;
mon->leak = 0;
memcpy(&mon->rmtadr, &rbufp->recv_srcadr, sizeof(mon->rmtadr));
mon->vn_mode = VN_MODE(version, mode);
mon->lcladr = rbufp->dstadr;
mon->cast_flags = (u_char)(((rbufp->dstadr->flags &
INT_MCASTOPEN) && rbufp->fd == mon->lcladr->fd) ? MDF_MCAST
: rbufp->fd == mon->lcladr->bfd ? MDF_BCAST : MDF_UCAST);
/*
* Drop him into front of the hash table. Also put him on top of
* the MRU list.
*/
LINK_SLIST(mon_hash[hash], mon, hash_next);
LINK_DLIST(mon_mru_list, mon, mru);
return mon->flags;
}
int
process_pkt (
struct pkt *rpkt,
sockaddr_u *sas,
int pkt_len,
int mode,
struct pkt *spkt,
const char * func_name
)
{
unsigned int key_id = 0;
struct key *pkt_key = NULL;
int is_authentic = 0;
unsigned int exten_words, exten_words_used = 0;
int mac_size;
/*
* Parse the extension field if present. We figure out whether
* an extension field is present by measuring the MAC size. If
* the number of words following the packet header is 0, no MAC
* is present and the packet is not authenticated. If 1, the
* packet is a crypto-NAK; if 3, the packet is authenticated
* with DES; if 5, the packet is authenticated with MD5; if 6,
* the packet is authenticated with SHA. If 2 or 4, the packet
* is a runt and discarded forthwith. If greater than 6, an
* extension field is present, so we subtract the length of the
* field and go around again.
*/
if (pkt_len < (int)LEN_PKT_NOMAC || (pkt_len & 3) != 0) {
unusable:
if (ENABLED_OPT(NORMALVERBOSE))
printf("sntp %s: Funny packet length: %i. Discarding package.\n", func_name, pkt_len);
return PACKET_UNUSEABLE;
}
/* skip past the extensions, if any */
exten_words = ((unsigned)pkt_len - LEN_PKT_NOMAC) >> 2;
while (exten_words > 6) {
unsigned int exten_len;
exten_len = ntohl(rpkt->exten[exten_words_used]) & 0xffff;
exten_len = (exten_len + 7) >> 2; /* convert to words, add 1 */
if (exten_len > exten_words || exten_len < 5)
goto unusable;
exten_words -= exten_len;
exten_words_used += exten_len;
}
switch (exten_words) {
case 1:
key_id = ntohl(rpkt->exten[exten_words_used]);
printf("Crypto NAK = 0x%08x\n", key_id);
break;
case 5:
case 6:
/* Look for the key used by the server in the specified keyfile
* and if existent, fetch it or else leave the pointer untouched */
key_id = ntohl(rpkt->exten[exten_words_used]);
get_key(key_id, &pkt_key);
if (!pkt_key) {
printf("unrecognized key ID = 0x%08x\n", key_id);
break;
}
/* Seems like we've got a key with matching keyid */
/* Generate a md5sum of the packet with the key from our keyfile
* and compare those md5sums */
mac_size = exten_words << 2;
if (!auth_md5((char *)rpkt, pkt_len - mac_size, mac_size - 4, pkt_key)) {
break;
}
/* Yay! Things worked out! */
if (ENABLED_OPT(NORMALVERBOSE)) {
char *hostname = ss_to_str(sas);
printf("sntp %s: packet received from %s successfully authenticated using key id %i.\n",
func_name, hostname, key_id);
free(hostname);
}
is_authentic = 1;
break;
case 0:
break;
default:
goto unusable;
break;
}
if (!is_authentic) {
if (ENABLED_OPT(AUTHENTICATION)) {
/* We want a authenticated packet */
if (ENABLED_OPT(NORMALVERBOSE)) {
char *hostname = ss_to_str(sas);
printf("sntp %s: packet received from %s is not authentic. Will discard it.\n",
func_name, hostname);
free(hostname);
}
return SERVER_AUTH_FAIL;
}
/* We don't know if the user wanted authentication so let's
* use it anyways */
if (ENABLED_OPT(NORMALVERBOSE)) {
char *hostname = ss_to_str(sas);
printf("sntp %s: packet received from %s is not authentic. Authentication not enforced.\n",
func_name, hostname);
free(hostname);
}
}
/* Check for server's ntp version */
if (PKT_VERSION(rpkt->li_vn_mode) < NTP_OLDVERSION ||
PKT_VERSION(rpkt->li_vn_mode) > NTP_VERSION) {
if (ENABLED_OPT(NORMALVERBOSE))
printf("sntp %s: Packet shows wrong version (%i)\n",
func_name, PKT_VERSION(rpkt->li_vn_mode));
return SERVER_UNUSEABLE;
}
/* We want a server to sync with */
if (PKT_MODE(rpkt->li_vn_mode) != mode &&
PKT_MODE(rpkt->li_vn_mode) != MODE_PASSIVE) {
if (ENABLED_OPT(NORMALVERBOSE))
printf("sntp %s: mode %d stratum %i\n", func_name,
PKT_MODE(rpkt->li_vn_mode), rpkt->stratum);
return SERVER_UNUSEABLE;
}
/* Stratum is unspecified (0) check what's going on */
if (STRATUM_PKT_UNSPEC == rpkt->stratum) {
char *ref_char;
if (ENABLED_OPT(NORMALVERBOSE))
printf("sntp %s: Stratum unspecified, going to check for KOD (stratum: %i)\n",
func_name, rpkt->stratum);
ref_char = (char *) &rpkt->refid;
if (ENABLED_OPT(NORMALVERBOSE))
printf("sntp %s: Packet refid: %c%c%c%c\n", func_name,
ref_char[0], ref_char[1], ref_char[2], ref_char[3]);
/* If it's a KOD packet we'll just use the KOD information */
if (ref_char[0] != 'X') {
if (strncmp(ref_char, "DENY", 4) == 0)
return KOD_DEMOBILIZE;
if (strncmp(ref_char, "RSTR", 4) == 0)
return KOD_DEMOBILIZE;
if (strncmp(ref_char, "RATE", 4) == 0)
return KOD_RATE;
/* There are other interesting kiss codes which might be interesting for authentication */
}
}
/* If the server is not synced it's not really useable for us */
if (LEAP_NOTINSYNC == PKT_LEAP(rpkt->li_vn_mode)) {
if (ENABLED_OPT(NORMALVERBOSE))
printf("sntp %s: Server not in sync, skipping this server\n", func_name);
return SERVER_UNUSEABLE;
}
/*
* Decode the org timestamp and make sure we're getting a response
* to our last request, but only if we're not in broadcast mode.
*/
#ifdef DEBUG
printf("rpkt->org:\n");
l_fp_output(&rpkt->org, stdout);
printf("spkt->xmt:\n");
l_fp_output(&spkt->xmt, stdout);
#endif
if (mode != MODE_BROADCAST && !L_ISEQU(&rpkt->org, &spkt->xmt)) {
if (ENABLED_OPT(NORMALVERBOSE))
printf("sntp process_pkt: pkt.org and peer.xmt differ\n");
return PACKET_UNUSEABLE;
}
return pkt_len;
}
/*
** Check if it's data for us and whether it's useable or not.
**
** If not, return a failure code so we can delete this server from our list
** and continue with another one.
*/
int
process_pkt (
struct pkt *rpkt,
sockaddr_u *sender,
int pkt_len,
int mode,
struct pkt *spkt,
const char * func_name
)
{
u_int key_id;
struct key * pkt_key;
int is_authentic;
int mac_size;
u_int exten_len;
u_int32 * exten_end;
u_int32 * packet_end;
l_fp sent_xmt;
l_fp resp_org;
// key_id = 0;
pkt_key = NULL;
is_authentic = (HAVE_OPT(AUTHENTICATION)) ? 0 : -1;
/*
* Parse the extension field if present. We figure out whether
* an extension field is present by measuring the MAC size. If
* the number of words following the packet header is 0, no MAC
* is present and the packet is not authenticated. If 1, the
* packet is a crypto-NAK; if 3, the packet is authenticated
* with DES; if 5, the packet is authenticated with MD5; if 6,
* the packet is authenticated with SHA. If 2 or 4, the packet
* is a runt and discarded forthwith. If greater than 6, an
* extension field is present, so we subtract the length of the
* field and go around again.
*/
if (pkt_len < (int)LEN_PKT_NOMAC || (pkt_len & 3) != 0) {
msyslog(LOG_ERR,
"%s: Incredible packet length: %d. Discarding.",
func_name, pkt_len);
return PACKET_UNUSEABLE;
}
/* HMS: the following needs a bit of work */
/* Note: pkt_len must be a multiple of 4 at this point! */
packet_end = (void*)((char*)rpkt + pkt_len);
exten_end = skip_efields(rpkt->exten, packet_end);
if (NULL == exten_end) {
msyslog(LOG_ERR,
"%s: Missing extension field. Discarding.",
func_name);
return PACKET_UNUSEABLE;
}
/* get size of MAC in cells; can be zero */
exten_len = (u_int)(packet_end - exten_end);
/* deduce action required from remaining length */
switch (exten_len) {
case 0: /* no Legacy MAC */
break;
case 1: /* crypto NAK */
/* Only if the keyID is 0 and there were no EFs */
key_id = ntohl(*exten_end);
printf("Crypto NAK = 0x%08x from %s\n", key_id, stoa(sender));
break;
case 3: /* key ID + 3DES MAC -- unsupported! */
msyslog(LOG_ERR,
"%s: Key ID + 3DES MAC is unsupported. Discarding.",
func_name);
return PACKET_UNUSEABLE;
case 5: /* key ID + MD5 MAC */
case 6: /* key ID + SHA MAC */
/*
** Look for the key used by the server in the specified
** keyfile and if existent, fetch it or else leave the
** pointer untouched
*/
key_id = ntohl(*exten_end);
get_key(key_id, &pkt_key);
if (!pkt_key) {
printf("unrecognized key ID = 0x%08x\n", key_id);
break;
}
/*
** Seems like we've got a key with matching keyid.
**
** Generate a md5sum of the packet with the key from our
** keyfile and compare those md5sums.
*/
mac_size = exten_len << 2;
if (!auth_md5(rpkt, pkt_len - mac_size,
mac_size - 4, pkt_key)) {
is_authentic = FALSE;
break;
}
/* Yay! Things worked out! */
is_authentic = TRUE;
TRACE(1, ("sntp %s: packet from %s authenticated using key id %d.\n",
func_name, stoa(sender), key_id));
break;
default:
msyslog(LOG_ERR,
"%s: Unexpected extension length: %d. Discarding.",
func_name, exten_len);
return PACKET_UNUSEABLE;
}
switch (is_authentic) {
case -1: /* unknown */
break;
case 0: /* not authentic */
return SERVER_AUTH_FAIL;
break;
case 1: /* authentic */
break;
default: /* error */
break;
}
/* Check for server's ntp version */
if (PKT_VERSION(rpkt->li_vn_mode) < NTP_OLDVERSION ||
PKT_VERSION(rpkt->li_vn_mode) > NTP_VERSION) {
msyslog(LOG_ERR,
"%s: Packet shows wrong version (%d)",
func_name, PKT_VERSION(rpkt->li_vn_mode));
return SERVER_UNUSEABLE;
}
/* We want a server to sync with */
if (PKT_MODE(rpkt->li_vn_mode) != mode &&
PKT_MODE(rpkt->li_vn_mode) != MODE_PASSIVE) {
msyslog(LOG_ERR,
"%s: mode %d stratum %d", func_name,
PKT_MODE(rpkt->li_vn_mode), rpkt->stratum);
return SERVER_UNUSEABLE;
}
/* Stratum is unspecified (0) check what's going on */
if (STRATUM_PKT_UNSPEC == rpkt->stratum) {
char *ref_char;
TRACE(1, ("%s: Stratum unspecified, going to check for KOD (stratum: %d)\n",
func_name, rpkt->stratum));
ref_char = (char *) &rpkt->refid;
TRACE(1, ("%s: Packet refid: %c%c%c%c\n", func_name,
ref_char[0], ref_char[1], ref_char[2], ref_char[3]));
/* If it's a KOD packet we'll just use the KOD information */
if (ref_char[0] != 'X') {
if (strncmp(ref_char, "DENY", 4) == 0)
return KOD_DEMOBILIZE;
if (strncmp(ref_char, "RSTR", 4) == 0)
return KOD_DEMOBILIZE;
if (strncmp(ref_char, "RATE", 4) == 0)
return KOD_RATE;
/*
** There are other interesting kiss codes which
** might be interesting for authentication.
*/
}
}
/* If the server is not synced it's not really useable for us */
if (LEAP_NOTINSYNC == PKT_LEAP(rpkt->li_vn_mode)) {
msyslog(LOG_ERR,
"%s: %s not in sync, skipping this server",
func_name, stoa(sender));
return SERVER_UNUSEABLE;
}
/*
* Decode the org timestamp and make sure we're getting a response
* to our last request, but only if we're not in broadcast mode.
*/
if (MODE_BROADCAST == mode)
return pkt_len;
if (!L_ISEQU(&rpkt->org, &spkt->xmt)) {
NTOHL_FP(&rpkt->org, &resp_org);
NTOHL_FP(&spkt->xmt, &sent_xmt);
msyslog(LOG_ERR,
"%s response org expected to match sent xmt",
stoa(sender));
msyslog(LOG_ERR, "resp org: %s", prettydate(&resp_org));
msyslog(LOG_ERR, "sent xmt: %s", prettydate(&sent_xmt));
return PACKET_UNUSEABLE;
}
return pkt_len;
}
/* Fetch data, check if it's data for us and whether it's useable or not. If not, return
* a failure code so we can delete this server from our list and continue with another one.
*/
int
recvpkt (
SOCKET rsock,
struct pkt *rpkt,
struct pkt *spkt
)
{
sockaddr_u sender;
char *rdata /* , done */;
register int a;
int has_mac, is_authentic, pkt_len, orig_pkt_len;
/* Much space, just to be sure */
rdata = emalloc(sizeof(char) * 256);
pkt_len = recvdata(rsock, &sender, rdata, 256);
#if 0 /* done uninitialized */
if (!done) {
/* Do something about it, first check for a maximum length of ntp packets,
* probably that's something we can avoid
*/
}
#endif
if (pkt_len < 0) {
if (ENABLED_OPT(NORMALVERBOSE)) {
printf("sntp recvpkt failed: %d.\n", pkt_len);
}
free(rdata);
return pkt_len;
}
/* Some checks to see if that packet is intended for us */
/* No MAC, no authentication */
if (LEN_PKT_NOMAC == pkt_len)
has_mac = 0;
/* If there's more than just the NTP packet it should be a MAC */
else if (pkt_len > LEN_PKT_NOMAC)
has_mac = pkt_len - LEN_PKT_NOMAC;
else {
if (ENABLED_OPT(NORMALVERBOSE))
printf("sntp recvpkt: Funny packet length: %i. Discarding package.\n", pkt_len);
free(rdata);
return PACKET_UNUSEABLE;
}
/* Packet too big */
if (pkt_len > LEN_PKT_MAC) {
if (ENABLED_OPT(NORMALVERBOSE))
printf("sntp recvpkt: Received packet is too big (%i bytes), trying again to get a useable packet\n",
pkt_len);
free(rdata);
return PACKET_UNUSEABLE;
}
orig_pkt_len = pkt_len;
pkt_len = min(pkt_len, sizeof(struct pkt));
for (a = 0; a < pkt_len; a++)
/* FIXME! */
if (a < orig_pkt_len)
((char *) rpkt)[a] = rdata[a];
else
((char *) rpkt)[a] = 0;
free(rdata);
rdata = NULL;
/* MAC could be useable for us */
if (has_mac) {
/* Two more things that the MAC must conform to */
if(has_mac > MAX_MAC_LEN || has_mac % 4 != 0) {
is_authentic = 0; /* Or should we discard this packet? */
}
else {
if (MAX_MAC_LEN == has_mac) {
struct key *pkt_key = NULL;
/*
* Look for the key used by the server in the specified keyfile
* and if existent, fetch it or else leave the pointer untouched
*/
get_key(rpkt->mac[0], &pkt_key);
/* Seems like we've got a key with matching keyid */
if (pkt_key != NULL) {
/*
* Generate a md5sum of the packet with the key from our keyfile
* and compare those md5sums
*/
if (!auth_md5((char *) rpkt, has_mac, pkt_key)) {
if (ENABLED_OPT(AUTHENTICATION)) {
/* We want a authenticated packet */
if (ENABLED_OPT(NORMALVERBOSE)) {
char *hostname = ss_to_str(&sender);
printf("sntp recvpkt: Broadcast packet received from %s is not authentic. Will discard this packet.\n",
hostname);
free(hostname);
}
return SERVER_AUTH_FAIL;
}
else {
/*
* We don't know if the user wanted authentication so let's
* use it anyways
*/
if (ENABLED_OPT(NORMALVERBOSE)) {
char *hostname = ss_to_str(&sender);
printf("sntp recvpkt: Broadcast packet received from %s is not authentic. Authentication not enforced.\n",
hostname);
free(hostname);
}
is_authentic = 0;
}
}
else {
/* Yay! Things worked out! */
if (ENABLED_OPT(NORMALVERBOSE)) {
char *hostname = ss_to_str(&sender);
printf("sntp recvpkt: Broadcast packet received from %s successfully authenticated using key id %i.\n",
hostname, rpkt->mac[0]);
free(hostname);
}
is_authentic = 1;
}
}
}
}
}
/* Check for server's ntp version */
if (PKT_VERSION(rpkt->li_vn_mode) < NTP_OLDVERSION ||
PKT_VERSION(rpkt->li_vn_mode) > NTP_VERSION) {
if (ENABLED_OPT(NORMALVERBOSE))
printf("sntp recvpkt: Packet got wrong version (%i)\n", PKT_VERSION(rpkt->li_vn_mode));
return SERVER_UNUSEABLE;
}
/* We want a server to sync with */
if (PKT_MODE(rpkt->li_vn_mode) != MODE_SERVER &&
PKT_MODE(rpkt->li_vn_mode) != MODE_PASSIVE) {
if (ENABLED_OPT(NORMALVERBOSE))
printf("sntp recvpkt: mode %d stratum %i\n",
PKT_MODE(rpkt->li_vn_mode), rpkt->stratum);
return SERVER_UNUSEABLE;
}
/* Stratum is unspecified (0) check what's going on */
if (STRATUM_PKT_UNSPEC == rpkt->stratum) {
char *ref_char;
if (ENABLED_OPT(NORMALVERBOSE))
printf("sntp recvpkt: Stratum unspecified, going to check for KOD (stratum: %i)\n", rpkt->stratum);
ref_char = (char *) &rpkt->refid;
if (ENABLED_OPT(NORMALVERBOSE))
printf("sntp recvpkt: Packet refid: %c%c%c%c\n", ref_char[0], ref_char[1], ref_char[2], ref_char[3]);
/* If it's a KOD packet we'll just use the KOD information */
if (ref_char[0] != 'X') {
if (!strncmp(ref_char, "DENY", 4))
return KOD_DEMOBILIZE;
if (!strncmp(ref_char, "RSTR", 4))
return KOD_DEMOBILIZE;
if (!strncmp(ref_char, "RATE", 4))
return KOD_RATE;
/* There are other interesting kiss codes which might be interesting for authentication */
}
}
/* If the server is not synced it's not really useable for us */
if (LEAP_NOTINSYNC == PKT_LEAP(rpkt->li_vn_mode)) {
if (ENABLED_OPT(NORMALVERBOSE))
printf("sntp recvpkt: Server not in sync, skipping this server\n");
return SERVER_UNUSEABLE;
}
/*
* Decode the org timestamp and make sure we're getting a response
* to our last request.
*/
#ifdef DEBUG
printf("rpkt->org:\n");
l_fp_output(&rpkt->org, stdout);
printf("spkt->xmt:\n");
l_fp_output(&spkt->xmt, stdout);
#endif
if (!L_ISEQU(&rpkt->org, &spkt->xmt)) {
if (ENABLED_OPT(NORMALVERBOSE))
printf("sntp recvpkt: pkt.org and peer.xmt differ\n");
return PACKET_UNUSEABLE;
}
return pkt_len;
}
int
recv_bcst_pkt (
SOCKET rsock,
struct pkt *rpkt,
sockaddr_u *sas
)
{
sockaddr_u sender;
register int a;
int is_authentic, has_mac = 0, orig_pkt_len;
char *rdata = emalloc(sizeof(char) * 256);
int pkt_len = recv_bcst_data(rsock, rdata, 256, sas, &sender);
if (pkt_len < 0) {
free(rdata);
return BROADCAST_FAILED;
}
/* No MAC, no authentication */
if (LEN_PKT_NOMAC == pkt_len)
has_mac = 0;
/* If there's more than just the NTP packet it should be a MAC */
else if(pkt_len > LEN_PKT_NOMAC)
has_mac = pkt_len - LEN_PKT_NOMAC;
else
if(ENABLED_OPT(NORMALVERBOSE)) {
printf("sntp recv_bcst_pkt: Funny packet length: %i. Discarding package.\n", pkt_len);
free(rdata);
return PACKET_UNUSEABLE;
}
/* Packet too big */
if(pkt_len > LEN_PKT_NOMAC + MAX_MAC_LEN) {
if(ENABLED_OPT(NORMALVERBOSE))
printf("sntp recv_bcst_pkt: Received packet is too big (%i bytes), trying again to get a useFable packet\n",
pkt_len);
free(rdata);
return PACKET_UNUSEABLE;
}
orig_pkt_len = pkt_len;
pkt_len = min(pkt_len, sizeof(struct pkt));
/* Let's copy the received data to the packet structure */
for (a = 0; a < pkt_len; a++)
if (a < orig_pkt_len)
((char *)rpkt)[a] = rdata[a];
else
((char *)rpkt)[a] = 0;
free(rdata);
/* MAC could be useable for us */
if (has_mac) {
/* Two more things that the MAC must conform to */
if (has_mac > MAX_MAC_LEN || has_mac % 4 != 0) {
is_authentic = 0; /* Or should we discard this packet? */
}
else {
if (MAX_MAC_LEN == has_mac) {
struct key *pkt_key = NULL;
/* Look for the key used by the server in the specified keyfile
* and if existent, fetch it or else leave the pointer untouched */
get_key(rpkt->mac[0], &pkt_key);
/* Seems like we've got a key with matching keyid */
if (pkt_key != NULL) {
/* Generate a md5sum of the packet with the key from our keyfile
* and compare those md5sums */
if (!auth_md5((char *) rpkt, has_mac, pkt_key)) {
if (ENABLED_OPT(AUTHENTICATION)) {
/* We want a authenticated packet */
if (ENABLED_OPT(NORMALVERBOSE)) {
char *hostname = ss_to_str(sas);
printf("sntp recv_bcst_pkt: Broadcast packet received from %s is not authentic. Will discard this packet.\n",
hostname);
free(hostname);
}
return SERVER_AUTH_FAIL;
}
else {
/* We don't know if the user wanted authentication so let's
* use it anyways */
if (ENABLED_OPT(NORMALVERBOSE)) {
char *hostname = ss_to_str(sas);
printf("sntp recv_bcst_pkt: Broadcast packet received from %s is not authentic. Authentication not enforced.\n",
hostname);
free(hostname);
}
is_authentic = 0;
}
}
else {
/* Yay! Things worked out! */
if (ENABLED_OPT(NORMALVERBOSE)) {
char *hostname = ss_to_str(sas);
printf("sntp recv_bcst_pkt: Broadcast packet received from %s successfully authenticated using key id %i.\n",
hostname, rpkt->mac[0]);
free(hostname);
}
is_authentic = 1;
}
}
}
}
}
/* Check for server's ntp version */
if (PKT_VERSION(rpkt->li_vn_mode) < NTP_OLDVERSION ||
PKT_VERSION(rpkt->li_vn_mode) > NTP_VERSION) {
if (ENABLED_OPT(NORMALVERBOSE))
printf("sntp recv_bcst_pkt: Packet shows wrong version (%i)\n",
PKT_VERSION(rpkt->li_vn_mode));
return SERVER_UNUSEABLE;
}
/* We want a server to sync with */
if (PKT_MODE(rpkt->li_vn_mode) != MODE_BROADCAST
&& PKT_MODE(rpkt->li_vn_mode) != MODE_PASSIVE) {
if (ENABLED_OPT(NORMALVERBOSE))
printf("sntp recv_bcst_pkt: mode %d stratum %i\n",
PKT_MODE(rpkt->li_vn_mode), rpkt->stratum);
return SERVER_UNUSEABLE;
}
if (STRATUM_PKT_UNSPEC == rpkt->stratum) {
char *ref_char;
if (ENABLED_OPT(NORMALVERBOSE))
printf("sntp recv_bcst_pkt: Stratum unspecified, going to check for KOD (stratum: %i)\n", rpkt->stratum);
ref_char = (char *) &rpkt->refid;
/* If it's a KOD packet we'll just use the KOD information */
if (ref_char[0] != 'X') {
if (strncmp(ref_char, "DENY", 4))
return KOD_DEMOBILIZE;
if (strncmp(ref_char, "RSTR", 4))
return KOD_DEMOBILIZE;
if (strncmp(ref_char, "RATE", 4))
return KOD_RATE;
/* There are other interesting kiss codes which might be interesting for authentication */
}
}
/* If the server is not synced it's not really useable for us */
if (LEAP_NOTINSYNC == PKT_LEAP(rpkt->li_vn_mode)) {
if (ENABLED_OPT(NORMALVERBOSE))
printf("recv_bcst_pkt: Server not in sync, skipping this server\n");
return SERVER_UNUSEABLE;
}
return pkt_len;
}
