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- Fix for #411, #439, #469: Reset the DNS message ID when moving queries

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between TCP streams.
- Refactor for uniform way to produce random DNS message IDs.
This commit is contained in:
George Thessalonikefs 2021-05-19 14:59:33 +02:00
parent 23152e6eb8
commit ff6b527184
4 changed files with 49 additions and 9 deletions
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5
doc/Changelog
View file

@ -1,3 +1,8 @@
19 May 2021: George
- Fix for #411, #439, #469: Reset the DNS message ID when moving queries
between TCP streams.
- Refactor for uniform way to produce random DNS message IDs.
17 May 2021: Wouter
- Fix #489: Compile using MSYS2 MinGW 64-bit.

4
services/authzone.c
View file

@ -5442,7 +5442,7 @@ xfr_transfer_init_fetch(struct auth_xfer* xfr, struct module_env* env)
/* perform AXFR/IXFR */
/* set the packet to be written */
/* create new ID */
xfr->task_transfer->id = (uint16_t)(ub_random(env->rnd)&0xffff);
xfr->task_transfer->id = GET_RANDOM_ID(env->rnd);
xfr_create_ixfr_packet(xfr, env->scratch_buffer,
xfr->task_transfer->id, master);
@ -6292,7 +6292,7 @@ xfr_probe_send_probe(struct auth_xfer* xfr, struct module_env* env,
/* create new ID for new probes, but not on timeout retries,
* this means we'll accept replies to previous retries to same ip */
if(timeout == AUTH_PROBE_TIMEOUT)
xfr->task_probe->id = (uint16_t)(ub_random(env->rnd)&0xffff);
xfr->task_probe->id = GET_RANDOM_ID(env->rnd);
xfr_create_soa_probe_packet(xfr, env->scratch_buffer,
xfr->task_probe->id);
/* we need to remove the cp if we have a different ip4/ip6 type now */

45
services/outside_network.c
View file

@ -94,6 +94,10 @@ static void waiting_list_remove(struct outside_network* outnet,
static void reuse_tcp_remove_tree_list(struct outside_network* outnet,
struct reuse_tcp* reuse);
/** select a DNS ID for a TCP stream */
static uint16_t tcp_select_id(struct outside_network* outnet,
struct reuse_tcp* reuse);
int
pending_cmp(const void* key1, const void* key2)
{
@ -406,9 +410,18 @@ static void reuse_write_wait_push_back(struct reuse_tcp* reuse,
void
reuse_tree_by_id_insert(struct reuse_tcp* reuse, struct waiting_tcp* w)
{
#ifdef UNBOUND_DEBUG
rbnode_type* added;
#endif
log_assert(w->id_node.key == NULL);
w->id_node.key = w;
#ifdef UNBOUND_DEBUG
added =
#else
(void)
#endif
rbtree_insert(&reuse->tree_by_id, &w->id_node);
log_assert(added); /* should have been added */
}
/** find element in tree by id */
@ -752,6 +765,9 @@ use_free_buffer(struct outside_network* outnet)
w->on_tcp_waiting_list = 0;
reuse = reuse_tcp_find(outnet, &w->addr, w->addrlen,
w->ssl_upstream);
/* re-select an ID when moving to a new TCP buffer */
w->id = tcp_select_id(outnet, reuse);
LDNS_ID_SET(w->pkt, w->id);
if(reuse) {
log_reuse_tcp(VERB_CLIENT, "use free buffer for waiting tcp: "
"found reuse", reuse);
@ -830,8 +846,17 @@ outnet_add_tcp_waiting(struct outside_network* outnet, struct waiting_tcp* w)
static void
reuse_tree_by_id_delete(struct reuse_tcp* reuse, struct waiting_tcp* w)
{
#ifdef UNBOUND_DEBUG
rbnode_type* rem;
#endif
log_assert(w->id_node.key != NULL);
#ifdef UNBOUND_DEBUG
rem =
#else
(void)
#endif
rbtree_delete(&reuse->tree_by_id, w);
log_assert(rem); /* should have been there */
w->id_node.key = NULL;
}
@ -1788,14 +1813,14 @@ select_id(struct outside_network* outnet, struct pending* pend,
sldns_buffer* packet)
{
int id_tries = 0;
pend->id = ((unsigned)ub_random(outnet->rnd)>>8) & 0xffff;
pend->id = GET_RANDOM_ID(outnet->rnd);
LDNS_ID_SET(sldns_buffer_begin(packet), pend->id);
/* insert in tree */
pend->node.key = pend;
while(!rbtree_insert(outnet->pending, &pend->node)) {
/* change ID to avoid collision */
pend->id = ((unsigned)ub_random(outnet->rnd)>>8) & 0xffff;
pend->id = GET_RANDOM_ID(outnet->rnd);
LDNS_ID_SET(sldns_buffer_begin(packet), pend->id);
id_tries++;
if(id_tries == MAX_ID_RETRY) {
@ -2088,6 +2113,14 @@ reuse_tcp_close_oldest(struct outside_network* outnet)
reuse_cb_and_decommission(outnet, pend, NETEVENT_CLOSED);
}
static uint16_t
tcp_select_id(struct outside_network* outnet, struct reuse_tcp* reuse)
{
if(reuse)
return reuse_tcp_select_id(reuse, outnet);
return GET_RANDOM_ID(outnet->rnd);
}
/** find spare ID value for reuse tcp stream. That is random and also does
* not collide with an existing query ID that is in use or waiting */
uint16_t
@ -2101,13 +2134,13 @@ reuse_tcp_select_id(struct reuse_tcp* reuse, struct outside_network* outnet)
/* make really sure the tree is not empty */
if(reuse->tree_by_id.count == 0) {
id = ((unsigned)ub_random(outnet->rnd)>>8) & 0xffff;
id = GET_RANDOM_ID(outnet->rnd);
return id;
}
/* try to find random empty spots by picking them */
for(i = 0; i<try_random; i++) {
id = ((unsigned)ub_random(outnet->rnd)>>8) & 0xffff;
id = GET_RANDOM_ID(outnet->rnd);
if(!reuse_tcp_by_id_find(reuse, id)) {
return id;
}
@ -2205,9 +2238,7 @@ pending_tcp_query(struct serviced_query* sq, sldns_buffer* packet,
w->pkt = (uint8_t*)w + sizeof(struct waiting_tcp);
w->pkt_len = sldns_buffer_limit(packet);
memmove(w->pkt, sldns_buffer_begin(packet), w->pkt_len);
if(reuse)
w->id = reuse_tcp_select_id(reuse, sq->outnet);
else w->id = ((unsigned)ub_random(sq->outnet->rnd)>>8) & 0xffff;
w->id = tcp_select_id(sq->outnet, reuse);
LDNS_ID_SET(w->pkt, w->id);
memcpy(&w->addr, &sq->addr, sq->addrlen);
w->addrlen = sq->addrlen;

4
util/net_help.h
View file

@ -42,6 +42,7 @@
#ifndef NET_HELP_H
#define NET_HELP_H
#include "util/log.h"
#include "util/random.h"
struct sock_list;
struct regional;
struct config_strlist;
@ -92,6 +93,9 @@ extern uint16_t EDNS_ADVERTISED_SIZE;
/** DNSKEY secure entry point, KSK flag */
#define DNSKEY_BIT_SEP 0x0001
/** return a random 16-bit number given a random source */
#define GET_RANDOM_ID(rnd) (((unsigned)ub_random(rnd)>>8) & 0xffff)
/** minimal responses when positive answer */
extern int MINIMAL_RESPONSES;