vendor/unbound/1.6.6

5 files changed, 136 insertions, 70 deletions

diff --git a/daemon/daemon.c b/daemon/daemon.c
index dad9f86b344e5..7411fabe75736 100644
--- a/daemon/daemon.c
+++ b/daemon/daemon.c
@@ -221,7 +221,9 @@ daemon_init(void)
 #  ifdef HAVE_ERR_LOAD_CRYPTO_STRINGS
 	ERR_load_crypto_strings();
 #  endif
+#if OPENSSL_VERSION_NUMBER < 0x10100000 || !defined(HAVE_OPENSSL_INIT_SSL)
 	ERR_load_SSL_strings();
+#endif
 #  ifdef USE_GOST
 	(void)sldns_key_EVP_load_gost_id();
 #  endif
@@ -239,7 +241,7 @@ daemon_init(void)
 #  if OPENSSL_VERSION_NUMBER < 0x10100000 || !defined(HAVE_OPENSSL_INIT_SSL)
 	(void)SSL_library_init();
 #  else
-	(void)OPENSSL_init_ssl(0, NULL);
+	(void)OPENSSL_init_ssl(OPENSSL_INIT_LOAD_SSL_STRINGS, NULL);
 #  endif
 #  if defined(HAVE_SSL) && defined(OPENSSL_THREADS) && !defined(THREADS_DISABLED)
 	if(!ub_openssl_lock_init())
@@ -421,8 +423,8 @@ daemon_create_workers(struct daemon* daemon)
 		daemon->rand = ub_initstate(seed, NULL);
 		if(!daemon->rand)
 			fatal_exit("could not init random generator");
+		hash_set_raninit((uint32_t)ub_random(daemon->rand));
 	}
-	hash_set_raninit((uint32_t)ub_random(daemon->rand));
 	shufport = (int*)calloc(65536, sizeof(int));
 	if(!shufport)
 		fatal_exit("out of memory during daemon init");
@@ -691,6 +693,9 @@ daemon_cleanup(struct daemon* daemon)
 #ifdef USE_DNSTAP
 	dt_delete(daemon->dtenv);
 #endif
+#ifdef USE_DNSCRYPT
+	dnsc_delete(daemon->dnscenv);
+#endif
 	daemon->cfg = NULL;
 }
 
diff --git a/daemon/remote.c b/daemon/remote.c
index bb41cc5df2dbb..243d94c49aa16 100644
--- a/daemon/remote.c
+++ b/daemon/remote.c
@@ -229,42 +229,10 @@ daemon_remote_create(struct config_file* cfg)
 		free(rc);
 		return NULL;
 	}
-	/* no SSLv2, SSLv3 because has defects */
-	if((SSL_CTX_set_options(rc->ctx, SSL_OP_NO_SSLv2) & SSL_OP_NO_SSLv2)
-		!= SSL_OP_NO_SSLv2){
-		log_crypto_err("could not set SSL_OP_NO_SSLv2");
+	if(!listen_sslctx_setup(rc->ctx)) {
 		daemon_remote_delete(rc);
 		return NULL;
 	}
-	if((SSL_CTX_set_options(rc->ctx, SSL_OP_NO_SSLv3) & SSL_OP_NO_SSLv3)
-		!= SSL_OP_NO_SSLv3){
-		log_crypto_err("could not set SSL_OP_NO_SSLv3");
-		daemon_remote_delete(rc);
-		return NULL;
-	}
-#if defined(SSL_OP_NO_TLSv1) && defined(SSL_OP_NO_TLSv1_1)
-	/* if we have tls 1.1 disable 1.0 */
-	if((SSL_CTX_set_options(rc->ctx, SSL_OP_NO_TLSv1) & SSL_OP_NO_TLSv1)
-		!= SSL_OP_NO_TLSv1){
-		log_crypto_err("could not set SSL_OP_NO_TLSv1");
-		daemon_remote_delete(rc);
-		return NULL;
-	}
-#endif
-#if defined(SSL_OP_NO_TLSv1_1) && defined(SSL_OP_NO_TLSv1_2)
-	/* if we have tls 1.2 disable 1.1 */
-	if((SSL_CTX_set_options(rc->ctx, SSL_OP_NO_TLSv1_1) & SSL_OP_NO_TLSv1_1)
-		!= SSL_OP_NO_TLSv1_1){
-		log_crypto_err("could not set SSL_OP_NO_TLSv1_1");
-		daemon_remote_delete(rc);
-		return NULL;
-	}
-#endif
-#if defined(SHA256_DIGEST_LENGTH) && defined(USE_ECDSA)
-	/* if we have sha256, set the cipher list to have no known vulns */
-	if(!SSL_CTX_set_cipher_list(rc->ctx, "ECDHE-ECDSA-CHACHA20-POLY1305:ECDHE-RSA-CHACHA20-POLY1305:ECDHE-ECDSA-AES256-GCM-SHA384:ECDHE-RSA-AES256-GCM-SHA384:ECDHE-ECDSA-AES128-GCM-SHA256:ECDHE-RSA-AES128-GCM-SHA256"))
-		log_crypto_err("could not set cipher list with SSL_CTX_set_cipher_list");
-#endif
 
 	if (cfg->remote_control_use_cert == 0) {
 		/* No certificates are requested */
@@ -314,23 +282,7 @@ daemon_remote_create(struct config_file* cfg)
 		log_crypto_err("Error in SSL_CTX check_private_key");
 		goto setup_error;
 	}
-#if HAVE_DECL_SSL_CTX_SET_ECDH_AUTO
-	if(!SSL_CTX_set_ecdh_auto(rc->ctx,1)) {
-		log_crypto_err("Error in SSL_CTX_ecdh_auto, not enabling ECDHE");
-	}
-#elif defined(USE_ECDSA)
-	if(1) {
-		EC_KEY *ecdh = EC_KEY_new_by_curve_name (NID_X9_62_prime256v1);
-		if (!ecdh) {
-			log_crypto_err("could not find p256, not enabling ECDHE");
-		} else {
-			if (1 != SSL_CTX_set_tmp_ecdh (rc->ctx, ecdh)) {
-				log_crypto_err("Error in SSL_CTX_set_tmp_ecdh, not enabling ECDHE");
-			}
-			EC_KEY_free (ecdh);
-		}
-	}
-#endif
+	listen_sslctx_setup_2(rc->ctx);
 	if(!SSL_CTX_load_verify_locations(rc->ctx, s_cert, NULL)) {
 		log_crypto_err("Error setting up SSL_CTX verify locations");
 	setup_error:
@@ -415,7 +367,7 @@ add_open(const char* ip, int nr, struct listen_port** list, int noproto_is_err,
 			if (cfg->username && cfg->username[0] &&
 				cfg_uid != (uid_t)-1) {
 				if(chown(ip, cfg_uid, cfg_gid) == -1)
-					log_err("cannot chown %u.%u %s: %s",
+					verbose(VERB_QUERY, "cannot chown %u.%u %s: %s",
 					  (unsigned)cfg_uid, (unsigned)cfg_gid,
 					  ip, strerror(errno));
 			}
@@ -841,7 +793,7 @@ print_stats(SSL* ssl, const char* nm, struct ub_stats_info* s)
 static int
 print_thread_stats(SSL* ssl, int i, struct ub_stats_info* s)
 {
-	char nm[16];
+	char nm[32];
 	snprintf(nm, sizeof(nm), "thread%d", i);
 	nm[sizeof(nm)-1]=0;
 	return print_stats(ssl, nm, s);
@@ -873,6 +825,9 @@ print_mem(SSL* ssl, struct worker* worker, struct daemon* daemon)
 #ifdef USE_IPSECMOD
 	size_t ipsecmod = 0;
 #endif /* USE_IPSECMOD */
+#ifdef USE_DNSCRYPT
+	size_t dnscrypt_shared_secret = 0;
+#endif /* USE_DNSCRYPT */
 	msg = slabhash_get_mem(daemon->env->msg_cache);
 	rrset = slabhash_get_mem(&daemon->env->rrset_cache->table);
 	val = mod_get_mem(&worker->env, "validator");
@@ -884,6 +839,12 @@ print_mem(SSL* ssl, struct worker* worker, struct daemon* daemon)
 #ifdef USE_IPSECMOD
 	ipsecmod = mod_get_mem(&worker->env, "ipsecmod");
 #endif /* USE_IPSECMOD */
+#ifdef USE_DNSCRYPT
+	if(daemon->dnscenv) {
+		dnscrypt_shared_secret = slabhash_get_mem(
+			daemon->dnscenv->shared_secrets_cache);
+	}
+#endif /* USE_DNSCRYPT */
 
 	if(!print_longnum(ssl, "mem.cache.rrset"SQ, rrset))
 		return 0;
@@ -903,6 +864,11 @@ print_mem(SSL* ssl, struct worker* worker, struct daemon* daemon)
 	if(!print_longnum(ssl, "mem.mod.ipsecmod"SQ, ipsecmod))
 		return 0;
 #endif /* USE_IPSECMOD */
+#ifdef USE_DNSCRYPT
+	if(!print_longnum(ssl, "mem.cache.dnscrypt_shared_secret"SQ,
+			dnscrypt_shared_secret))
+		return 0;
+#endif /* USE_DNSCRYPT */
 	return 1;
 }
 
@@ -1065,6 +1031,9 @@ print_ext(SSL* ssl, struct ub_stats_info* s)
 		if(!ssl_printf(ssl, "num.answer.rcode.nodata"SQ"%lu\n", 
 			(unsigned long)s->svr.ans_rcode_nodata)) return 0;
 	}
+	/* iteration */
+	if(!ssl_printf(ssl, "num.query.ratelimited"SQ"%lu\n", 
+		(unsigned long)s->svr.queries_ratelimited)) return 0;
 	/* validation */
 	if(!ssl_printf(ssl, "num.answer.secure"SQ"%lu\n", 
 		(unsigned long)s->svr.ans_secure)) return 0;
@@ -1086,6 +1055,12 @@ print_ext(SSL* ssl, struct ub_stats_info* s)
 		(unsigned)s->svr.infra_cache_count)) return 0;
 	if(!ssl_printf(ssl, "key.cache.count"SQ"%u\n",
 		(unsigned)s->svr.key_cache_count)) return 0;
+#ifdef USE_DNSCRYPT
+	if(!ssl_printf(ssl, "dnscrypt_shared_secret.cache.count"SQ"%u\n",
+		(unsigned)s->svr.shared_secret_cache_count)) return 0;
+	if(!ssl_printf(ssl, "num.query.dnscrypt.shared_secret.cachemiss"SQ"%lu\n",
+		(unsigned long)s->svr.num_query_dnscrypt_secret_missed_cache)) return 0;
+#endif /* USE_DNSCRYPT */
 	return 1;
 }
 
@@ -2389,10 +2364,16 @@ dump_infra_host(struct lruhash_entry* e, void* arg)
 	struct infra_data* d = (struct infra_data*)e->data;
 	char ip_str[1024];
 	char name[257];
+	int port;
 	if(a->ssl_failed)
 		return;
 	addr_to_str(&k->addr, k->addrlen, ip_str, sizeof(ip_str));
 	dname_str(k->zonename, name);
+	port = (int)ntohs(((struct sockaddr_in*)&k->addr)->sin_port);
+	if(port != UNBOUND_DNS_PORT) {
+		snprintf(ip_str+strlen(ip_str), sizeof(ip_str)-strlen(ip_str),
+			"@%d", port);
+	}
 	/* skip expired stuff (only backed off) */
 	if(d->ttl < a->now) {
 		if(d->rtt.rto >= USEFUL_SERVER_TOP_TIMEOUT) {
diff --git a/daemon/stats.c b/daemon/stats.c
index 599f39bcddda0..1058556be7c26 100644
--- a/daemon/stats.c
+++ b/daemon/stats.c
@@ -56,6 +56,7 @@
 #include "util/timehist.h"
 #include "util/net_help.h"
 #include "validator/validator.h"
+#include "iterator/iterator.h"
 #include "sldns/sbuffer.h"
 #include "services/cache/rrset.h"
 #include "services/cache/infra.h"
@@ -123,7 +124,7 @@ void server_stats_log(struct ub_server_stats* stats, struct worker* worker,
 
 /** get rrsets bogus number from validator */
 static size_t
-get_rrset_bogus(struct worker* worker)
+get_rrset_bogus(struct worker* worker, int reset)
 {
 	int m = modstack_find(&worker->env.mesh->mods, "validator");
 	struct val_env* ve;
@@ -133,12 +134,48 @@ get_rrset_bogus(struct worker* worker)
 	ve = (struct val_env*)worker->env.modinfo[m];
 	lock_basic_lock(&ve->bogus_lock);
 	r = ve->num_rrset_bogus;
-	if(!worker->env.cfg->stat_cumulative)
+	if(reset && !worker->env.cfg->stat_cumulative)
 		ve->num_rrset_bogus = 0;
 	lock_basic_unlock(&ve->bogus_lock);
 	return r;
 }
 
+/** get number of ratelimited queries from iterator */
+static size_t
+get_queries_ratelimit(struct worker* worker, int reset)
+{
+	int m = modstack_find(&worker->env.mesh->mods, "iterator");
+	struct iter_env* ie;
+	size_t r;
+	if(m == -1)
+		return 0;
+	ie = (struct iter_env*)worker->env.modinfo[m];
+	lock_basic_lock(&ie->queries_ratelimit_lock);
+	r = ie->num_queries_ratelimited;
+	if(reset && !worker->env.cfg->stat_cumulative)
+		ie->num_queries_ratelimited = 0;
+	lock_basic_unlock(&ie->queries_ratelimit_lock);
+	return r;
+}
+
+#ifdef USE_DNSCRYPT
+/** get the number of shared secret cache miss */
+static size_t
+get_dnscrypt_cache_miss(struct worker* worker, int reset)
+{
+	size_t r;
+	struct dnsc_env* de = worker->daemon->dnscenv;
+	if(!de) return 0;
+
+	lock_basic_lock(&de->shared_secrets_cache_lock);
+	r = de->num_query_dnscrypt_secret_missed_cache;
+	if(reset && !worker->env.cfg->stat_cumulative)
+		de->num_query_dnscrypt_secret_missed_cache = 0;
+	lock_basic_unlock(&de->shared_secrets_cache_lock);
+	return r;
+}
+#endif /* USE_DNSCRYPT */
+
 void
 server_stats_compile(struct worker* worker, struct ub_stats_info* s, int reset)
 {
@@ -169,7 +206,10 @@ server_stats_compile(struct worker* worker, struct ub_stats_info* s, int reset)
 	s->svr.qtcp_outgoing = (long long)worker->back->num_tcp_outgoing;
 
 	/* get and reset validator rrset bogus number */
-	s->svr.rrset_bogus = (long long)get_rrset_bogus(worker);
+	s->svr.rrset_bogus = (long long)get_rrset_bogus(worker, reset);
+
+	/* get and reset iterator query ratelimit number */
+	s->svr.queries_ratelimited = (long long)get_queries_ratelimit(worker, reset);
 
 	/* get cache sizes */
 	s->svr.msg_cache_count = (long long)count_slabhash_entries(worker->env.msg_cache);
@@ -179,6 +219,21 @@ server_stats_compile(struct worker* worker, struct ub_stats_info* s, int reset)
 		s->svr.key_cache_count = (long long)count_slabhash_entries(worker->env.key_cache->slab);
 	else	s->svr.key_cache_count = 0;
 
+#ifdef USE_DNSCRYPT
+	if(worker->daemon->dnscenv) {
+		s->svr.num_query_dnscrypt_secret_missed_cache =
+			(long long)get_dnscrypt_cache_miss(worker, reset);
+		s->svr.shared_secret_cache_count = (long long)count_slabhash_entries(
+			worker->daemon->dnscenv->shared_secrets_cache);
+	} else {
+		s->svr.num_query_dnscrypt_secret_missed_cache = 0;
+		s->svr.shared_secret_cache_count = 0;
+	}
+#else
+	s->svr.num_query_dnscrypt_secret_missed_cache = 0;
+	s->svr.shared_secret_cache_count = 0;
+#endif /* USE_DNSCRYPT */
+
 	/* get tcp accept usage */
 	s->svr.tcp_accept_usage = 0;
 	for(lp = worker->front->cps; lp; lp = lp->next) {
@@ -240,7 +295,7 @@ void server_stats_add(struct ub_stats_info* total, struct ub_stats_info* a)
 		a->svr.num_query_dnscrypt_cleartext;
 	total->svr.num_query_dnscrypt_crypted_malformed += \
 		a->svr.num_query_dnscrypt_crypted_malformed;
-#endif
+#endif /* USE_DNSCRYPT */
 	/* the max size reached is upped to higher of both */
 	if(a->svr.max_query_list_size > total->svr.max_query_list_size)
 		total->svr.max_query_list_size = a->svr.max_query_list_size;
@@ -266,7 +321,6 @@ void server_stats_add(struct ub_stats_info* total, struct ub_stats_info* a)
 		total->svr.zero_ttl_responses += a->svr.zero_ttl_responses;
 		total->svr.ans_secure += a->svr.ans_secure;
 		total->svr.ans_bogus += a->svr.ans_bogus;
-		total->svr.rrset_bogus += a->svr.rrset_bogus;
 		total->svr.unwanted_replies += a->svr.unwanted_replies;
 		total->svr.unwanted_queries += a->svr.unwanted_queries;
 		total->svr.tcp_accept_usage += a->svr.tcp_accept_usage;
diff --git a/daemon/unbound.c b/daemon/unbound.c
index ba7337d8907ad..070a824d67343 100644
--- a/daemon/unbound.c
+++ b/daemon/unbound.c
@@ -128,6 +128,9 @@ static void usage(void)
 	for(m = module_list_avail(); *m; m++)
 		printf(" %s", *m);
 	printf("\n");
+#ifdef USE_DNSCRYPT
+	printf("DNSCrypt feature available\n");
+#endif
 	printf("BSD licensed, see LICENSE in source package for details.\n");
 	printf("Report bugs to %s\n", PACKAGE_BUGREPORT);
 	ub_event_base_free(base);
@@ -400,7 +403,7 @@ detach(void)
 /** daemonize, drop user priviliges and chroot if needed */
 static void
 perform_setup(struct daemon* daemon, struct config_file* cfg, int debug_mode,
-	const char** cfgfile)
+	const char** cfgfile, int need_pidfile)
 {
 #ifdef HAVE_KILL
 	int pidinchroot;
@@ -444,13 +447,13 @@ perform_setup(struct daemon* daemon, struct config_file* cfg, int debug_mode,
 
 #ifdef HAVE_KILL
 	/* true if pidfile is inside chrootdir, or nochroot */
-	pidinchroot = !(cfg->chrootdir && cfg->chrootdir[0]) ||
+	pidinchroot = need_pidfile && (!(cfg->chrootdir && cfg->chrootdir[0]) ||
 				(cfg->chrootdir && cfg->chrootdir[0] &&
 				strncmp(cfg->pidfile, cfg->chrootdir,
-				strlen(cfg->chrootdir))==0);
+				strlen(cfg->chrootdir))==0));
 
 	/* check old pid file before forking */
-	if(cfg->pidfile && cfg->pidfile[0]) {
+	if(cfg->pidfile && cfg->pidfile[0] && need_pidfile) {
 		/* calculate position of pidfile */
 		if(cfg->pidfile[0] == '/')
 			daemon->pidfile = strdup(cfg->pidfile);
@@ -469,7 +472,7 @@ perform_setup(struct daemon* daemon, struct config_file* cfg, int debug_mode,
 
 	/* write new pidfile (while still root, so can be outside chroot) */
 #ifdef HAVE_KILL
-	if(cfg->pidfile && cfg->pidfile[0]) {
+	if(cfg->pidfile && cfg->pidfile[0] && need_pidfile) {
 		writepid(daemon->pidfile, getpid());
 		if(cfg->username && cfg->username[0] && cfg_uid != (uid_t)-1 &&
 			pidinchroot) {
@@ -484,6 +487,7 @@ perform_setup(struct daemon* daemon, struct config_file* cfg, int debug_mode,
 	}
 #else
 	(void)daemon;
+	(void)need_pidfile;
 #endif /* HAVE_KILL */
 
 	/* Set user context */
@@ -600,9 +604,10 @@ perform_setup(struct daemon* daemon, struct config_file* cfg, int debug_mode,
  *    These increase verbosity as specified in the config file.
  * @param debug_mode: if set, do not daemonize.
  * @param log_default_identity: Default identity to report in logs
+ * @param need_pidfile: if false, no pidfile is checked or created.
  */
 static void 
-run_daemon(const char* cfgfile, int cmdline_verbose, int debug_mode, const char* log_default_identity)
+run_daemon(const char* cfgfile, int cmdline_verbose, int debug_mode, const char* log_default_identity, int need_pidfile)
 {
 	struct config_file* cfg = NULL;
 	struct daemon* daemon = NULL;
@@ -632,7 +637,7 @@ run_daemon(const char* cfgfile, int cmdline_verbose, int debug_mode, const char*
 		if(!daemon_open_shared_ports(daemon))
 			fatal_exit("could not open ports");
 		if(!done_setup) { 
-			perform_setup(daemon, cfg, debug_mode, &cfgfile);
+			perform_setup(daemon, cfg, debug_mode, &cfgfile, need_pidfile);
 			done_setup = 1; 
 		} else {
 			/* reopen log after HUP to facilitate log rotation */
@@ -682,6 +687,8 @@ main(int argc, char* argv[])
 	const char* log_ident_default;
 	int cmdline_verbose = 0;
 	int debug_mode = 0;
+	int need_pidfile = 1;
+
 #ifdef UB_ON_WINDOWS
 	int cmdline_cfg = 0;
 #endif
@@ -690,7 +697,7 @@ main(int argc, char* argv[])
 	log_ident_default = strrchr(argv[0],'/')?strrchr(argv[0],'/')+1:argv[0];
 	log_ident_set(log_ident_default);
 	/* parse the options */
-	while( (c=getopt(argc, argv, "c:dhvw:")) != -1) {
+	while( (c=getopt(argc, argv, "c:dhpvw:")) != -1) {
 		switch(c) {
 		case 'c':
 			cfgfile = optarg;
@@ -702,6 +709,9 @@ main(int argc, char* argv[])
 			cmdline_verbose++;
 			verbosity++;
 			break;
+		case 'p':
+			need_pidfile = 0;
+			break;
 		case 'd':
 			debug_mode++;
 			break;
@@ -732,7 +742,7 @@ main(int argc, char* argv[])
 		return 1;
 	}
 
-	run_daemon(cfgfile, cmdline_verbose, debug_mode, log_ident_default);
+	run_daemon(cfgfile, cmdline_verbose, debug_mode, log_ident_default, need_pidfile);
 	log_init(NULL, 0, NULL); /* close logfile */
 	return 0;
 }
diff --git a/daemon/worker.c b/daemon/worker.c
index 2c4cf5ba6c0a1..683f93169117d 100644
--- a/daemon/worker.c
+++ b/daemon/worker.c
@@ -1009,6 +1009,7 @@ worker_handle_request(struct comm_point* c, void* arg, int error,
 	struct query_info* lookup_qinfo = &qinfo;
 	struct query_info qinfo_tmp; /* placeholdoer for lookup_qinfo */
 	struct respip_client_info* cinfo = NULL, cinfo_tmp;
+	memset(&qinfo, 0, sizeof(qinfo));
 
 	if(error != NETEVENT_NOERROR) {
 		/* some bad tcp query DNS formats give these error calls */
@@ -1111,6 +1112,7 @@ worker_handle_request(struct comm_point* c, void* arg, int error,
 	if(!query_info_parse(&qinfo, c->buffer)) {
 		verbose(VERB_ALGO, "worker parse request: formerror.");
 		log_addr(VERB_CLIENT,"from",&repinfo->addr, repinfo->addrlen);
+		memset(&qinfo, 0, sizeof(qinfo)); /* zero qinfo.qname */
 		if(worker_err_ratelimit(worker, LDNS_RCODE_FORMERR) == -1) {
 			comm_point_drop_reply(repinfo);
 			return 0;
@@ -1355,6 +1357,10 @@ lookup_cache:
 					lock_rw_unlock(&e->lock);
 					regional_free_all(worker->scratchpad);
 					goto send_reply;
+				} else {
+					/* Note that we've already released the
+					 * lock if we're here after prefetch. */
+					lock_rw_unlock(&e->lock);
 				}
 				/* We've found a partial reply ending with an
 				 * alias.  Replace the lookup qinfo for the
@@ -1362,7 +1368,6 @@ lookup_cache:
 				 * (possibly) complete the reply.  As we're
 				 * passing the "base" reply, there will be no
 				 * more alias chasing. */
-				lock_rw_unlock(&e->lock);
 				memset(&qinfo_tmp, 0, sizeof(qinfo_tmp));
 				get_cname_target(alias_rrset, &qinfo_tmp.qname,
 					&qinfo_tmp.qname_len);
@@ -1669,7 +1674,17 @@ worker_init(struct worker* worker, struct config_file *cfg,
 	worker->env.send_query = &worker_send_query;
 	worker->env.alloc = &worker->alloc;
 	worker->env.rnd = worker->rndstate;
-	worker->env.scratch = worker->scratchpad;
+	/* If case prefetch is triggered, the corresponding mesh will clear
+	 * the scratchpad for the module env in the middle of request handling.
+	 * It would be prone to a use-after-free kind of bug, so we avoid
+	 * sharing it with worker's own scratchpad at the cost of having
+	 * one more pad per worker. */
+	worker->env.scratch = regional_create_custom(cfg->msg_buffer_size);
+	if(!worker->env.scratch) {
+		log_err("malloc failure");
+		worker_delete(worker);
+		return 0;
+	}
 	worker->env.mesh = mesh_create(&worker->daemon->mods, &worker->env);
 	worker->env.detach_subs = &mesh_detach_subs;
 	worker->env.attach_sub = &mesh_attach_sub;
@@ -1758,6 +1773,7 @@ worker_delete(struct worker* worker)
 	comm_base_delete(worker->base);
 	ub_randfree(worker->rndstate);
 	alloc_clear(&worker->alloc);
+	regional_destroy(worker->env.scratch);
 	regional_destroy(worker->scratchpad);
 	free(worker);
 }