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Merge pull request #20002 from yuwata/sd-dhcp-client-ignore-forcerenew

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sd-dhcp-client: ignore FORCERENEW
This commit is contained in:
Luca Boccassi 2021-06-24 10:01:10 +01:00 committed by GitHub
commit 6222acc2b5
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1 changed files with 72 additions and 68 deletions
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140
src/libsystemd-network/sd-dhcp-client.c
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@ -1587,9 +1587,17 @@ static int client_handle_forcerenew(sd_dhcp_client *client, DHCPMessage *force,
if (r != DHCP_FORCERENEW)
return -ENOMSG;
#if 0
log_dhcp_client(client, "FORCERENEW");
return 0;
#else
/* FIXME: Ignore FORCERENEW requests until we implement RFC3118 (Authentication for DHCP
* Messages) and/or RFC6704 (Forcerenew Nonce Authentication), as unauthenticated FORCERENEW
* requests causes a security issue (TALOS-2020-1142, CVE-2020-13529). */
log_dhcp_client(client, "Received FORCERENEW, ignoring.");
return -ENOMSG;
#endif
}
static bool lease_equal(const sd_dhcp_lease *a, const sd_dhcp_lease *b) {
@ -1777,7 +1785,7 @@ static int client_set_lease_timeouts(sd_dhcp_client *client) {
static int client_handle_message(sd_dhcp_client *client, DHCPMessage *message, int len) {
DHCP_CLIENT_DONT_DESTROY(client);
char time_string[FORMAT_TIMESPAN_MAX];
int r = 0, notify_event = 0;
int r, notify_event;
assert(client);
assert(client->event);
@ -1787,22 +1795,19 @@ static int client_handle_message(sd_dhcp_client *client, DHCPMessage *message, i
case DHCP_STATE_SELECTING:
r = client_handle_offer(client, message, len);
if (r >= 0) {
if (r == -ENOMSG)
return 0; /* invalid message, let's ignore it */
if (r < 0)
goto error;
client->state = DHCP_STATE_REQUESTING;
client->attempt = 0;
r = event_reset_time(client->event, &client->timeout_resend,
clock_boottime_or_monotonic(),
0, 0,
client_timeout_resend, client,
client->event_priority, "dhcp4-resend-timer", true);
if (r < 0)
goto error;
} else if (r == -ENOMSG)
/* invalid message, let's ignore it */
return 0;
client->state = DHCP_STATE_REQUESTING;
client->attempt = 0;
r = event_reset_time(client->event, &client->timeout_resend,
clock_boottime_or_monotonic(),
0, 0,
client_timeout_resend, client,
client->event_priority, "dhcp4-resend-timer", true);
break;
case DHCP_STATE_REBOOTING:
@ -1811,47 +1816,9 @@ static int client_handle_message(sd_dhcp_client *client, DHCPMessage *message, i
case DHCP_STATE_REBINDING:
r = client_handle_ack(client, message, len);
if (r >= 0) {
client->start_delay = 0;
(void) event_source_disable(client->timeout_resend);
client->receive_message =
sd_event_source_unref(client->receive_message);
client->fd = safe_close(client->fd);
if (IN_SET(client->state, DHCP_STATE_REQUESTING,
DHCP_STATE_REBOOTING))
notify_event = SD_DHCP_CLIENT_EVENT_IP_ACQUIRE;
else if (r != SD_DHCP_CLIENT_EVENT_IP_ACQUIRE)
notify_event = r;
client->state = DHCP_STATE_BOUND;
client->attempt = 0;
client->last_addr = client->lease->address;
r = client_set_lease_timeouts(client);
if (r < 0) {
log_dhcp_client(client, "could not set lease timeouts");
goto error;
}
r = dhcp_network_bind_udp_socket(client->ifindex, client->lease->address, client->port, client->ip_service_type);
if (r < 0) {
log_dhcp_client(client, "could not bind UDP socket");
goto error;
}
client->fd = r;
client_initialize_io_events(client, client_receive_message_udp);
if (notify_event) {
client_notify(client, notify_event);
if (client->state == DHCP_STATE_STOPPED)
return 0;
}
} else if (r == -EADDRNOTAVAIL) {
if (r == -ENOMSG)
return 0; /* invalid message, let's ignore it */
if (r == -EADDRNOTAVAIL) {
/* got a NAK, let's restart the client */
client_notify(client, SD_DHCP_CLIENT_EVENT_EXPIRED);
@ -1868,34 +1835,71 @@ static int client_handle_message(sd_dhcp_client *client, DHCPMessage *message, i
client->start_delay = CLAMP(client->start_delay * 2,
RESTART_AFTER_NAK_MIN_USEC, RESTART_AFTER_NAK_MAX_USEC);
return 0;
} else if (r == -ENOMSG)
/* invalid message, let's ignore it */
return 0;
}
if (r < 0)
goto error;
if (IN_SET(client->state, DHCP_STATE_REQUESTING, DHCP_STATE_REBOOTING))
notify_event = SD_DHCP_CLIENT_EVENT_IP_ACQUIRE;
else
notify_event = r;
client->start_delay = 0;
(void) event_source_disable(client->timeout_resend);
client->receive_message = sd_event_source_unref(client->receive_message);
client->fd = safe_close(client->fd);
client->state = DHCP_STATE_BOUND;
client->attempt = 0;
client->last_addr = client->lease->address;
r = client_set_lease_timeouts(client);
if (r < 0) {
log_dhcp_client(client, "could not set lease timeouts");
goto error;
}
r = dhcp_network_bind_udp_socket(client->ifindex, client->lease->address, client->port, client->ip_service_type);
if (r < 0) {
log_dhcp_client(client, "could not bind UDP socket");
goto error;
}
client->fd = r;
client_initialize_io_events(client, client_receive_message_udp);
if (IN_SET(client->state, DHCP_STATE_RENEWING, DHCP_STATE_REBINDING) &&
notify_event == SD_DHCP_CLIENT_EVENT_IP_ACQUIRE)
/* FIXME: hmm, maybe this is a bug... */
log_dhcp_client(client, "client_handle_ack() returned SD_DHCP_CLIENT_EVENT_IP_ACQUIRE while DHCP client is %s the address, skipping callback.",
client->state == DHCP_STATE_RENEWING ? "renewing" : "rebinding");
else
client_notify(client, notify_event);
break;
case DHCP_STATE_BOUND:
r = client_handle_forcerenew(client, message, len);
if (r >= 0) {
r = client_timeout_t1(NULL, 0, client);
if (r < 0)
goto error;
} else if (r == -ENOMSG)
/* invalid message, let's ignore it */
return 0;
if (r == -ENOMSG)
return 0; /* invalid message, let's ignore it */
if (r < 0)
goto error;
r = client_timeout_t1(NULL, 0, client);
break;
case DHCP_STATE_INIT:
case DHCP_STATE_INIT_REBOOT:
r = 0;
break;
case DHCP_STATE_STOPPED:
r = -EINVAL;
goto error;
default:
assert_not_reached("invalid state");
}
error: