Merge branch 'dnssec-limit'

This merges security fixes for CVE-2023-50387 and CVE-2023-50868

Keytrap - extreme CPU consumption in the DNSSEC validator.
This commit is contained in:
Simon Kelley
2024-02-13 13:27:25 +00:00
11 changed files with 570 additions and 281 deletions

View File

@@ -834,7 +834,18 @@ void cache_end_insert(void)
if (daemon->pipe_to_parent != -1)
{
ssize_t m = -1;
read_write(daemon->pipe_to_parent, (unsigned char *)&m, sizeof(m), 0);
#ifdef HAVE_DNSSEC
/* Sneak out possibly updated crypto HWM values. */
m = daemon->metrics[METRIC_CRYPTO_HWM];
read_write(daemon->pipe_to_parent, (unsigned char *)&m, sizeof(m), 0);
m = daemon->metrics[METRIC_SIG_FAIL_HWM];
read_write(daemon->pipe_to_parent, (unsigned char *)&m, sizeof(m), 0);
m = daemon->metrics[METRIC_WORK_HWM];
read_write(daemon->pipe_to_parent, (unsigned char *)&m, sizeof(m), 0);
#endif
}
new_chain = NULL;
@@ -853,7 +864,7 @@ int cache_recv_insert(time_t now, int fd)
cache_start_insert();
while(1)
while (1)
{
if (!read_write(fd, (unsigned char *)&m, sizeof(m), 1))
@@ -861,6 +872,21 @@ int cache_recv_insert(time_t now, int fd)
if (m == -1)
{
#ifdef HAVE_DNSSEC
/* Sneak in possibly updated crypto HWM. */
if (!read_write(fd, (unsigned char *)&m, sizeof(m), 1))
return 0;
if (m > daemon->metrics[METRIC_CRYPTO_HWM])
daemon->metrics[METRIC_CRYPTO_HWM] = m;
if (!read_write(fd, (unsigned char *)&m, sizeof(m), 1))
return 0;
if (m > daemon->metrics[METRIC_SIG_FAIL_HWM])
daemon->metrics[METRIC_SIG_FAIL_HWM] = m;
if (!read_write(fd, (unsigned char *)&m, sizeof(m), 1))
return 0;
if (m > daemon->metrics[METRIC_WORK_HWM])
daemon->metrics[METRIC_WORK_HWM] = m;
#endif
cache_end_insert();
return 1;
}
@@ -1893,6 +1919,11 @@ void dump_cache(time_t now)
#ifdef HAVE_AUTH
my_syslog(LOG_INFO, _("queries for authoritative zones %u"), daemon->metrics[METRIC_DNS_AUTH_ANSWERED]);
#endif
#ifdef HAVE_DNSSEC
my_syslog(LOG_INFO, _("DNSSEC per-query subqueries HWM %u"), daemon->metrics[METRIC_WORK_HWM]);
my_syslog(LOG_INFO, _("DNSSEC per-query crypto work HWM %u"), daemon->metrics[METRIC_CRYPTO_HWM]);
my_syslog(LOG_INFO, _("DNSSEC per-RRSet signature fails HWM %u"), daemon->metrics[METRIC_SIG_FAIL_HWM]);
#endif
blockdata_report();
my_syslog(LOG_INFO, _("child processes for TCP requests: in use %zu, highest since last SIGUSR1 %zu, max allowed %zu."),
@@ -2052,6 +2083,11 @@ static char *edestr(int ede)
case EDE_NO_AUTH: return "no reachable authority";
case EDE_NETERR: return "network error";
case EDE_INVALID_DATA: return "invalid data";
case EDE_SIG_E_B_V: return "signature expired before valid";
case EDE_TOO_EARLY: return "too early";
case EDE_UNS_NS3_ITER: return "unsupported NSEC3 iterations value";
case EDE_UNABLE_POLICY: return "uanble to conform to policy";
case EDE_SYNTHESIZED: return "synthesized";
default: return "unknown";
}
}

View File

@@ -22,7 +22,10 @@
#define EDNS_PKTSZ 1232 /* default max EDNS.0 UDP packet from from /dnsflagday.net/2020 */
#define SAFE_PKTSZ 1232 /* "go anywhere" UDP packet size, see https://dnsflagday.net/2020/ */
#define KEYBLOCK_LEN 40 /* choose to minimise fragmentation when storing DNSSEC keys */
#define DNSSEC_WORK 50 /* Max number of queries to validate one question */
#define DNSSEC_LIMIT_WORK 40 /* Max number of queries to validate one question */
#define DNSSEC_LIMIT_SIG_FAIL 20 /* Number of signature that can fail to validate in one answer */
#define DNSSEC_LIMIT_CRYPTO 200 /* max no. of crypto operations to validate one query. */
#define DNSSEC_LIMIT_NSEC3_ITERS 150 /* Max. number if iterations allowed in NSEC3 record. */
#define TIMEOUT 10 /* drop UDP queries after TIMEOUT seconds */
#define SMALL_PORT_RANGE 30 /* If DNS port range is smaller than this, use different allocation. */
#define FORWARD_TEST 50 /* try all servers every 50 queries */

View File

@@ -112,8 +112,11 @@
#define EDE_NO_AUTH 22 /* No Reachable Authority */
#define EDE_NETERR 23 /* Network error */
#define EDE_INVALID_DATA 24 /* Invalid Data */
#define EDE_SIG_E_B_V 25 /* Signature Expired before Valid */
#define EDE_TOO_EARLY 26 /* To Early */
#define EDE_UNS_NS3_ITER 27 /* Unsupported NSEC3 Iterations Value */
#define EDE_UNABLE_POLICY 28 /* Unable to conform to policy */
#define EDE_SYNTHESIZED 29 /* Synthesized */
struct dns_header {

View File

@@ -757,6 +757,9 @@ struct dyndir {
#define DNSSEC_FAIL_NONSEC 0x0040 /* No NSEC */
#define DNSSEC_FAIL_NODSSUP 0x0080 /* no supported DS algo. */
#define DNSSEC_FAIL_NOKEY 0x0100 /* no DNSKEY */
#define DNSSEC_FAIL_NSEC3_ITERS 0x0200 /* too many iterations in NSEC3 */
#define DNSSEC_FAIL_BADPACKET 0x0400 /* bad packet */
#define DNSSEC_FAIL_WORK 0x0800 /* too much crypto */
#define STAT_ISEQUAL(a, b) (((a) & 0xffff0000) == (b))
@@ -794,7 +797,7 @@ struct frec {
struct blockdata *stash; /* Saved reply, whilst we validate */
size_t stash_len;
#ifdef HAVE_DNSSEC
int class, work_counter;
int class, work_counter, validate_counter;
struct frec *dependent; /* Query awaiting internally-generated DNSKEY or DS query */
struct frec *next_dependent; /* list of above. */
struct frec *blocking_query; /* Query which is blocking us. */
@@ -831,6 +834,12 @@ struct frec {
#define LEASE_HAVE_HWADDR 128 /* Have set hwaddress */
#define LEASE_EXP_CHANGED 256 /* Lease expiry time changed */
#define LIMIT_SIG_FAIL 0
#define LIMIT_CRYPTO 1
#define LIMIT_WORK 2
#define LIMIT_NSEC3_ITERS 3
#define LIMIT_MAX 4
struct dhcp_lease {
int clid_len; /* length of client identifier */
unsigned char *clid; /* clientid */
@@ -1240,6 +1249,7 @@ extern struct daemon {
int rr_status_sz;
int dnssec_no_time_check;
int back_to_the_future;
int limit[LIMIT_MAX];
#endif
struct frec *frec_list;
struct frec_src *free_frec_src;
@@ -1415,10 +1425,12 @@ int in_zone(struct auth_zone *zone, char *name, char **cut);
/* dnssec.c */
#ifdef HAVE_DNSSEC
size_t dnssec_generate_query(struct dns_header *header, unsigned char *end, char *name, int class, int type, int edns_pktsz);
int dnssec_validate_by_ds(time_t now, struct dns_header *header, size_t plen, char *name, char *keyname, int class);
int dnssec_validate_ds(time_t now, struct dns_header *header, size_t plen, char *name, char *keyname, int class);
int dnssec_validate_by_ds(time_t now, struct dns_header *header, size_t plen, char *name,
char *keyname, int class, int *validate_count);
int dnssec_validate_ds(time_t now, struct dns_header *header, size_t plen, char *name,
char *keyname, int class, int *validate_count);
int dnssec_validate_reply(time_t now, struct dns_header *header, size_t plen, char *name, char *keyname, int *class,
int check_unsigned, int *neganswer, int *nons, int *nsec_ttl);
int check_unsigned, int *neganswer, int *nons, int *nsec_ttl, int *validate_count);
int dnskey_keytag(int alg, int flags, unsigned char *key, int keylen);
size_t filter_rrsigs(struct dns_header *header, size_t plen);
int setup_timestamp(void);

File diff suppressed because it is too large Load Diff

View File

@@ -338,7 +338,8 @@ static int forward_query(int udpfd, union mysockaddr *udpaddr,
if (ad_reqd)
forward->flags |= FREC_AD_QUESTION;
#ifdef HAVE_DNSSEC
forward->work_counter = DNSSEC_WORK;
forward->work_counter = daemon->limit[LIMIT_WORK];
forward->validate_counter = daemon->limit[LIMIT_CRYPTO];
if (do_bit)
forward->flags |= FREC_DO_QUESTION;
#endif
@@ -892,6 +893,9 @@ static size_t process_reply(struct dns_header *header, time_t now, struct server
static void dnssec_validate(struct frec *forward, struct dns_header *header,
ssize_t plen, int status, time_t now)
{
struct frec *orig;
int log_resource = 0;
daemon->log_display_id = forward->frec_src.log_id;
/* We've had a reply already, which we're validating. Ignore this duplicate */
@@ -916,6 +920,9 @@ static void dnssec_validate(struct frec *forward, struct dns_header *header,
log_query(F_UPSTREAM | F_NOEXTRA, daemon->namebuff, NULL, "truncated", (forward->flags & FREC_DNSKEY_QUERY) ? T_DNSKEY : T_DS);
}
}
/* Find the original query that started it all.... */
for (orig = forward; orig->dependent; orig = orig->dependent);
/* As soon as anything returns BOGUS, we stop and unwind, to do otherwise
would invite infinite loops, since the answers to DNSKEY and DS queries
@@ -923,19 +930,17 @@ static void dnssec_validate(struct frec *forward, struct dns_header *header,
if (!STAT_ISEQUAL(status, STAT_BOGUS) && !STAT_ISEQUAL(status, STAT_TRUNCATED) && !STAT_ISEQUAL(status, STAT_ABANDONED))
{
if (forward->flags & FREC_DNSKEY_QUERY)
status = dnssec_validate_by_ds(now, header, plen, daemon->namebuff, daemon->keyname, forward->class);
status = dnssec_validate_by_ds(now, header, plen, daemon->namebuff, daemon->keyname, forward->class, &orig->validate_counter);
else if (forward->flags & FREC_DS_QUERY)
status = dnssec_validate_ds(now, header, plen, daemon->namebuff, daemon->keyname, forward->class);
status = dnssec_validate_ds(now, header, plen, daemon->namebuff, daemon->keyname, forward->class, &orig->validate_counter);
else
status = dnssec_validate_reply(now, header, plen, daemon->namebuff, daemon->keyname, &forward->class,
!option_bool(OPT_DNSSEC_IGN_NS) && (forward->sentto->flags & SERV_DO_DNSSEC),
NULL, NULL, NULL);
#ifdef HAVE_DUMPFILE
if (STAT_ISEQUAL(status, STAT_BOGUS))
dump_packet_udp((forward->flags & (FREC_DNSKEY_QUERY | FREC_DS_QUERY)) ? DUMP_SEC_BOGUS : DUMP_BOGUS,
header, (size_t)plen, &forward->sentto->addr, NULL, -daemon->port);
#endif
NULL, NULL, NULL, &orig->validate_counter);
}
if (STAT_ISEQUAL(status, STAT_ABANDONED))
log_resource = 1;
/* Can't validate, as we're missing key data. Put this
answer aside, whilst we get that. */
@@ -979,18 +984,19 @@ static void dnssec_validate(struct frec *forward, struct dns_header *header,
return;
}
}
else if (orig->work_counter-- == 0)
{
my_syslog(LOG_WARNING, _("limit exceeded: per-query subqueries"));
log_resource = 1;
}
else
{
struct server *server;
struct frec *orig;
void *hash;
size_t nn;
int serverind, fd;
struct randfd_list *rfds = NULL;
/* Find the original query that started it all.... */
for (orig = forward; orig->dependent; orig = orig->dependent);
/* Make sure we don't expire and free the orig frec during the
allocation of a new one: third arg of get_new_frec() does that. */
if ((serverind = dnssec_server(forward->sentto, daemon->keyname, NULL, NULL)) != -1 &&
@@ -999,7 +1005,6 @@ static void dnssec_validate(struct frec *forward, struct dns_header *header,
daemon->keyname, forward->class,
STAT_ISEQUAL(status, STAT_NEED_KEY) ? T_DNSKEY : T_DS, server->edns_pktsz)) &&
(hash = hash_questions(header, nn, daemon->namebuff)) &&
--orig->work_counter != 0 &&
(fd = allocate_rfd(&rfds, server)) != -1 &&
(new = get_new_frec(now, server, 1)))
{
@@ -1065,6 +1070,21 @@ static void dnssec_validate(struct frec *forward, struct dns_header *header,
status = STAT_ABANDONED;
}
if (log_resource)
{
/* Log the actual validation that made us barf. */
unsigned char *p = (unsigned char *)(header+1);
if (extract_name(header, plen, &p, daemon->namebuff, 0, 4) == 1)
my_syslog(LOG_WARNING, _("validation of %s failed: resource limit exceeded."),
daemon->namebuff[0] ? daemon->namebuff : ".");
}
#ifdef HAVE_DUMPFILE
if (STAT_ISEQUAL(status, STAT_BOGUS) || STAT_ISEQUAL(status, STAT_ABANDONED))
dump_packet_udp((forward->flags & (FREC_DNSKEY_QUERY | FREC_DS_QUERY)) ? DUMP_SEC_BOGUS : DUMP_BOGUS,
header, (size_t)plen, &forward->sentto->addr, NULL, -daemon->port);
#endif
/* Validated original answer, all done. */
if (!forward->dependent)
return_reply(now, forward, header, plen, status);
@@ -1073,7 +1093,7 @@ static void dnssec_validate(struct frec *forward, struct dns_header *header,
/* validated subsidiary query/queries, (and cached result)
pop that and return to the previous query/queries we were working on. */
struct frec *prev, *nxt = forward->dependent;
free_frec(forward);
while ((prev = nxt))
@@ -1337,6 +1357,12 @@ static void return_reply(time_t now, struct frec *forward, struct dns_header *he
log_query(F_SECSTAT, domain, &a, result, 0);
}
}
if ((daemon->limit[LIMIT_CRYPTO] - forward->validate_counter) > (int)daemon->metrics[METRIC_CRYPTO_HWM])
daemon->metrics[METRIC_CRYPTO_HWM] = daemon->limit[LIMIT_CRYPTO] - forward->validate_counter;
if ((daemon->limit[LIMIT_WORK] - forward->work_counter) > (int)daemon->metrics[METRIC_WORK_HWM])
daemon->metrics[METRIC_WORK_HWM] = daemon->limit[LIMIT_WORK] - forward->work_counter;
#endif
if (option_bool(OPT_NO_REBIND))
@@ -2018,7 +2044,7 @@ static ssize_t tcp_talk(int first, int last, int start, unsigned char *packet,
/* Recurse down the key hierarchy */
static int tcp_key_recurse(time_t now, int status, struct dns_header *header, size_t n,
int class, char *name, char *keyname, struct server *server,
int have_mark, unsigned int mark, int *keycount)
int have_mark, unsigned int mark, int *keycount, int *validatecount)
{
int first, last, start, new_status;
unsigned char *packet = NULL;
@@ -2030,20 +2056,34 @@ static int tcp_key_recurse(time_t now, int status, struct dns_header *header, si
int log_save;
/* limit the amount of work we do, to avoid cycling forever on loops in the DNS */
if (--(*keycount) == 0)
new_status = STAT_ABANDONED;
else if (STAT_ISEQUAL(status, STAT_NEED_KEY))
new_status = dnssec_validate_by_ds(now, header, n, name, keyname, class);
if (STAT_ISEQUAL(status, STAT_NEED_KEY))
new_status = dnssec_validate_by_ds(now, header, n, name, keyname, class, validatecount);
else if (STAT_ISEQUAL(status, STAT_NEED_DS))
new_status = dnssec_validate_ds(now, header, n, name, keyname, class);
new_status = dnssec_validate_ds(now, header, n, name, keyname, class, validatecount);
else
new_status = dnssec_validate_reply(now, header, n, name, keyname, &class,
!option_bool(OPT_DNSSEC_IGN_NS) && (server->flags & SERV_DO_DNSSEC),
NULL, NULL, NULL);
NULL, NULL, NULL, validatecount);
if (!STAT_ISEQUAL(new_status, STAT_NEED_DS) && !STAT_ISEQUAL(new_status, STAT_NEED_KEY))
if (!STAT_ISEQUAL(new_status, STAT_NEED_DS) && !STAT_ISEQUAL(new_status, STAT_NEED_KEY) && !STAT_ISEQUAL(new_status, STAT_ABANDONED))
break;
if ((*keycount)-- == 0)
{
my_syslog(LOG_WARNING, _("limit exceeded: per-query subqueries"));
new_status = STAT_ABANDONED;
}
if (STAT_ISEQUAL(new_status, STAT_ABANDONED))
{
/* Log the actual validation that made us barf. */
unsigned char *p = (unsigned char *)(header+1);
if (extract_name(header, n, &p, daemon->namebuff, 0, 4) == 1)
my_syslog(LOG_WARNING, _("validation of %s failed: resource limit exceeded."),
daemon->namebuff[0] ? daemon->namebuff : ".");
break;
}
/* Can't validate because we need a key/DS whose name now in keyname.
Make query for same, and recurse to validate */
if (!packet)
@@ -2057,7 +2097,7 @@ static int tcp_key_recurse(time_t now, int status, struct dns_header *header, si
new_status = STAT_ABANDONED;
break;
}
m = dnssec_generate_query(new_header, ((unsigned char *) new_header) + 65536, keyname, class,
STAT_ISEQUAL(new_status, STAT_NEED_KEY) ? T_DNSKEY : T_DS, server->edns_pktsz);
@@ -2072,10 +2112,11 @@ static int tcp_key_recurse(time_t now, int status, struct dns_header *header, si
daemon->log_display_id = ++daemon->log_id;
log_query_mysockaddr(F_NOEXTRA | F_DNSSEC | F_SERVER, keyname, &server->addr,
STAT_ISEQUAL(new_status, STAT_NEED_KEY) ? "dnssec-query[DNSKEY]" : "dnssec-query[DS]", 0);
new_status = tcp_key_recurse(now, new_status, new_header, m, class, name, keyname, server, have_mark, mark, keycount);
STAT_ISEQUAL(new_status, STAT_NEED_KEY) ? "dnssec-query[DNSKEY]" : "dnssec-query[DS]", 0);
new_status = tcp_key_recurse(now, new_status, new_header, m, class, name, keyname, server,
have_mark, mark, keycount, validatecount);
daemon->log_display_id = log_save;
if (!STAT_ISEQUAL(new_status, STAT_OK))
@@ -2379,9 +2420,10 @@ unsigned char *tcp_request(int confd, time_t now,
#ifdef HAVE_DNSSEC
if (option_bool(OPT_DNSSEC_VALID) && !checking_disabled && (master->flags & SERV_DO_DNSSEC))
{
int keycount = DNSSEC_WORK; /* Limit to number of DNSSEC questions, to catch loops and avoid filling cache. */
int keycount = daemon->limit[LIMIT_WORK]; /* Limit to number of DNSSEC questions, to catch loops and avoid filling cache. */
int validatecount = daemon->limit[LIMIT_CRYPTO];
int status = tcp_key_recurse(now, STAT_OK, header, m, 0, daemon->namebuff, daemon->keyname,
serv, have_mark, mark, &keycount);
serv, have_mark, mark, &keycount, &validatecount);
char *result, *domain = "result";
union all_addr a;
@@ -2407,6 +2449,12 @@ unsigned char *tcp_request(int confd, time_t now,
}
log_query(F_SECSTAT, domain, &a, result, 0);
if ((daemon->limit[LIMIT_CRYPTO] - validatecount) > (int)daemon->metrics[METRIC_CRYPTO_HWM])
daemon->metrics[METRIC_CRYPTO_HWM] = daemon->limit[LIMIT_CRYPTO] - validatecount;
if ((daemon->limit[LIMIT_WORK] - keycount) > (int)daemon->metrics[METRIC_WORK_HWM])
daemon->metrics[METRIC_WORK_HWM] = daemon->limit[LIMIT_WORK] - keycount;
}
#endif

View File

@@ -24,6 +24,9 @@ const char * metric_names[] = {
"dns_local_answered",
"dns_stale_answered",
"dns_unanswered",
"dnssec_max_crypto_use",
"dnssec_max_sig_fail",
"dnssec_max_work",
"bootp",
"pxe",
"dhcp_ack",

View File

@@ -23,6 +23,9 @@ enum {
METRIC_DNS_LOCAL_ANSWERED,
METRIC_DNS_STALE_ANSWERED,
METRIC_DNS_UNANSWERED_QUERY,
METRIC_CRYPTO_HWM,
METRIC_SIG_FAIL_HWM,
METRIC_WORK_HWM,
METRIC_BOOTP,
METRIC_PXE,
METRIC_DHCPACK,

View File

@@ -191,6 +191,7 @@ struct myoption {
#define LOPT_NO_DHCP6 382
#define LOPT_NO_DHCP4 383
#define LOPT_MAX_PROCS 384
#define LOPT_DNSSEC_LIMITS 385
#ifdef HAVE_GETOPT_LONG
static const struct option opts[] =
@@ -364,6 +365,7 @@ static const struct myoption opts[] =
{ "dnssec-check-unsigned", 2, 0, LOPT_DNSSEC_CHECK },
{ "dnssec-no-timecheck", 0, 0, LOPT_DNSSEC_TIME },
{ "dnssec-timestamp", 1, 0, LOPT_DNSSEC_STAMP },
{ "dnssec-limits", 1, 0, LOPT_DNSSEC_LIMITS },
{ "dhcp-relay", 1, 0, LOPT_RELAY },
{ "ra-param", 1, 0, LOPT_RA_PARAM },
{ "quiet-dhcp", 0, 0, LOPT_QUIET_DHCP },
@@ -568,6 +570,7 @@ static struct {
{ LOPT_DNSSEC_CHECK, ARG_DUP, NULL, gettext_noop("Ensure answers without DNSSEC are in unsigned zones."), NULL },
{ LOPT_DNSSEC_TIME, OPT_DNSSEC_TIME, NULL, gettext_noop("Don't check DNSSEC signature timestamps until first cache-reload"), NULL },
{ LOPT_DNSSEC_STAMP, ARG_ONE, "<path>", gettext_noop("Timestamp file to verify system clock for DNSSEC"), NULL },
{ LOPT_DNSSEC_LIMITS, ARG_ONE, "<limit>,..", gettext_noop("Set resource limits for DNSSEC validation"), NULL },
{ LOPT_RA_PARAM, ARG_DUP, "<iface>,[mtu:<value>|<interface>|off,][<prio>,]<intval>[,<lifetime>]", gettext_noop("Set MTU, priority, resend-interval and router-lifetime"), NULL },
{ LOPT_QUIET_DHCP, OPT_QUIET_DHCP, NULL, gettext_noop("Do not log routine DHCP."), NULL },
{ LOPT_QUIET_DHCP6, OPT_QUIET_DHCP6, NULL, gettext_noop("Do not log routine DHCPv6."), NULL },
@@ -5258,6 +5261,24 @@ err:
}
#ifdef HAVE_DNSSEC
case LOPT_DNSSEC_LIMITS:
{
int lim, val;
for (lim = LIMIT_SIG_FAIL; arg && lim < LIMIT_MAX ; lim++, arg = comma)
{
comma = split(arg);
if (!atoi_check(arg, &val))
ret_err(gen_err);
if (val != 0)
daemon->limit[lim] = val;
}
break;
}
case LOPT_DNSSEC_STAMP: /* --dnssec-timestamp */
daemon->timestamp_file = opt_string_alloc(arg);
break;
@@ -5869,7 +5890,12 @@ void read_opts(int argc, char **argv, char *compile_opts)
daemon->randport_limit = 1;
daemon->host_index = SRC_AH;
daemon->max_procs = MAX_PROCS;
daemon->max_procs_used = 0;
#ifdef HAVE_DNSSEC
daemon->limit[LIMIT_SIG_FAIL] = DNSSEC_LIMIT_SIG_FAIL;
daemon->limit[LIMIT_CRYPTO] = DNSSEC_LIMIT_CRYPTO;
daemon->limit[LIMIT_WORK] = DNSSEC_LIMIT_WORK;
daemon->limit[LIMIT_NSEC3_ITERS] = DNSSEC_LIMIT_NSEC3_ITERS;
#endif
/* See comment above make_servers(). Optimises server-read code. */
mark_servers(0);