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feat(mdns): add check of instance when handling PTR query
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@gytxxsy
gytxxsy committed May 31, 2024
1 parent 3f12ef6 commit 6af6ca5
Showing 1 changed file with 105 additions and 5 deletions.
110 changes: 105 additions & 5 deletions components/mdns/mdns.c
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Original file line number Diff line number Diff line change
Expand Up @@ -1871,21 +1871,44 @@ static void _mdns_create_answer_from_parsed_packet(mdns_parsed_packet_t *parsed_
packet->id = parsed_packet->id;

mdns_parsed_question_t *q = parsed_packet->questions;
uint32_t out_record_nums = 0;
while (q) {
shared = q->type == MDNS_TYPE_PTR || q->type == MDNS_TYPE_SDPTR || !parsed_packet->probe;
if (q->type == MDNS_TYPE_SRV || q->type == MDNS_TYPE_TXT) {
mdns_srv_item_t *service = _mdns_get_service_item_instance(q->host, q->service, q->proto, NULL);
if (service == NULL || !_mdns_create_answer_from_service(packet, service->service, q, shared, send_flush)) {
_mdns_free_tx_packet(packet);
return;
} else {
out_record_nums++;
}
} else if (q->service && q->proto) {
mdns_srv_item_t *service = _mdns_server->services;
while (service) {
if (_mdns_service_match_ptr_question(service->service, q)) {
if (!_mdns_create_answer_from_service(packet, service->service, q, shared, send_flush)) {
_mdns_free_tx_packet(packet);
return;
mdns_parsed_record_t *r = parsed_packet->records;
bool is_record_exist = false;
while (r) {
if (service->service->instance && r->host) {
if (_mdns_service_match_instance(service->service, r->host, r->service, r->proto, NULL) && r->ttl > (MDNS_ANSWER_PTR_TTL / 2)) {
is_record_exist = true;
break;
}
} else if (!service->service->instance && !r->host) {
if (_mdns_service_match(service->service, r->service, r->proto, NULL) && r->ttl > (MDNS_ANSWER_PTR_TTL / 2)) {
is_record_exist = true;
break;
}
}
r = r->next;
}
if (!is_record_exist) {
if (!_mdns_create_answer_from_service(packet, service->service, q, shared, send_flush)) {
_mdns_free_tx_packet(packet);
return;
} else {
out_record_nums++;
}
}
}
service = service->next;
Expand All @@ -1894,22 +1917,31 @@ static void _mdns_create_answer_from_parsed_packet(mdns_parsed_packet_t *parsed_
if (!_mdns_create_answer_from_hostname(packet, q->host, send_flush)) {
_mdns_free_tx_packet(packet);
return;
} else {
out_record_nums++;
}
} else if (q->type == MDNS_TYPE_ANY) {
if (!_mdns_append_host_list(&packet->answers, send_flush, false)) {
_mdns_free_tx_packet(packet);
return;
} else {
out_record_nums++;
}
#ifdef CONFIG_MDNS_RESPOND_REVERSE_QUERIES
} else if (q->type == MDNS_TYPE_PTR) {
mdns_host_item_t *host = mdns_get_host_item(q->host);
if (!_mdns_alloc_answer(&packet->answers, MDNS_TYPE_PTR, NULL, host, send_flush, false)) {
_mdns_free_tx_packet(packet);
return;
} else {
out_record_nums++;
}
#endif /* CONFIG_MDNS_RESPOND_REVERSE_QUERIES */
} else if (!_mdns_alloc_answer(&packet->answers, q->type, NULL, NULL, send_flush, false)) {
_mdns_free_tx_packet(packet);
return;
} else {
out_record_nums++;
}

if (parsed_packet->src_port != MDNS_SERVICE_PORT && // Repeat the queries only for "One-Shot mDNS queries"
Expand Down Expand Up @@ -1943,6 +1975,10 @@ static void _mdns_create_answer_from_parsed_packet(mdns_parsed_packet_t *parsed_
}
q = q->next;
}
if (out_record_nums == 0) {
_mdns_free_tx_packet(packet);
return;
}
if (unicast || !send_flush) {
memcpy(&packet->dst, &parsed_packet->src, sizeof(esp_ip_addr_t));
packet->port = parsed_packet->src_port;
Expand Down Expand Up @@ -3336,7 +3372,11 @@ static bool _mdns_question_matches(mdns_parsed_question_t *question, uint16_t ty
&& !strcasecmp(service->service->service, question->service)
&& !strcasecmp(service->service->proto, question->proto)
&& !strcasecmp(MDNS_DEFAULT_DOMAIN, question->domain)) {
return true;
if (!service->service->instance) {
return true;
} else if (service->service->instance && question->host && !strcasecmp(service->service->instance, question->host)) {
return true;
}
}
} else if (service && (type == MDNS_TYPE_SRV || type == MDNS_TYPE_TXT)) {
const char *name = _mdns_get_service_instance_name(service->service);
Expand Down Expand Up @@ -3635,6 +3675,7 @@ void mdns_parse_packet(mdns_rx_packet_t *packet)
parsed_packet->id = header.id;
esp_netif_ip_addr_copy(&parsed_packet->src, &packet->src);
parsed_packet->src_port = packet->src_port;
parsed_packet->records = NULL;

if (header.questions) {
uint8_t qs = header.questions;
Expand Down Expand Up @@ -3821,7 +3862,12 @@ void mdns_parse_packet(mdns_rx_packet_t *packet)
_mdns_search_result_add_ptr(search_result, name->host, name->service, name->proto,
packet->tcpip_if, packet->ip_protocol, ttl);
} else if ((discovery || ours) && !name->sub && _mdns_name_is_ours(name)) {
if (discovery && (service = _mdns_get_service_item(name->service, name->proto, NULL))) {
if (name->host[0]) {
service = _mdns_get_service_item_instance(name->host, name->service, name->proto, NULL);
} else {
service = _mdns_get_service_item(name->service, name->proto, NULL);
}
if (discovery && service) {
_mdns_remove_parsed_question(parsed_packet, MDNS_TYPE_SDPTR, service);
} else if (service && parsed_packet->questions && !parsed_packet->probe) {
_mdns_remove_parsed_question(parsed_packet, type, service);
Expand All @@ -3831,6 +3877,45 @@ void mdns_parse_packet(mdns_rx_packet_t *packet)
_mdns_remove_scheduled_answer(packet->tcpip_if, packet->ip_protocol, type, service);
}
}
if (service) {
mdns_parsed_record_t *record = malloc(sizeof(mdns_parsed_record_t));
if (!record) {
HOOK_MALLOC_FAILED;
goto clear_rx_packet;
}
record->next = parsed_packet->records;
parsed_packet->records = record;
record->type = MDNS_TYPE_PTR;
record->record_type = MDNS_ANSWER;
record->ttl = ttl;
record->host = NULL;
record->service = NULL;
record->proto = NULL;
if (name->host[0]) {
record->host = malloc(MDNS_NAME_BUF_LEN);
if (!record->host) {
HOOK_MALLOC_FAILED;
goto clear_rx_packet;
}
memcpy(record->host, name->host, MDNS_NAME_BUF_LEN);

Check warning

Code scanning / clang-tidy

Call to function 'memcpy' is insecure as it does not provide security checks introduced in the C11 standard. Replace with analogous functions that support length arguments or provides boundary checks such as 'memcpy_s' in case of C11 [clang-analyzer-security.insecureAPI.DeprecatedOrUnsafeBufferHandling] Warning

Call to function 'memcpy' is insecure as it does not provide security checks introduced in the C11 standard. Replace with analogous functions that support length arguments or provides boundary checks such as 'memcpy_s' in case of C11 [clang-analyzer-security.insecureAPI.DeprecatedOrUnsafeBufferHandling]
}
if (name->service[0]) {
record->service = malloc(MDNS_NAME_BUF_LEN);
if (!record->service) {
HOOK_MALLOC_FAILED;
goto clear_rx_packet;
}
memcpy(record->service, name->service, MDNS_NAME_BUF_LEN);

Check warning

Code scanning / clang-tidy

Call to function 'memcpy' is insecure as it does not provide security checks introduced in the C11 standard. Replace with analogous functions that support length arguments or provides boundary checks such as 'memcpy_s' in case of C11 [clang-analyzer-security.insecureAPI.DeprecatedOrUnsafeBufferHandling] Warning

Call to function 'memcpy' is insecure as it does not provide security checks introduced in the C11 standard. Replace with analogous functions that support length arguments or provides boundary checks such as 'memcpy_s' in case of C11 [clang-analyzer-security.insecureAPI.DeprecatedOrUnsafeBufferHandling]
}
if (name->proto[0]) {
record->proto = malloc(MDNS_NAME_BUF_LEN);
if (!record->proto) {
HOOK_MALLOC_FAILED;
goto clear_rx_packet;
}
memcpy(record->proto, name->proto, MDNS_NAME_BUF_LEN);

Check warning

Code scanning / clang-tidy

Call to function 'memcpy' is insecure as it does not provide security checks introduced in the C11 standard. Replace with analogous functions that support length arguments or provides boundary checks such as 'memcpy_s' in case of C11 [clang-analyzer-security.insecureAPI.DeprecatedOrUnsafeBufferHandling] Warning

Call to function 'memcpy' is insecure as it does not provide security checks introduced in the C11 standard. Replace with analogous functions that support length arguments or provides boundary checks such as 'memcpy_s' in case of C11 [clang-analyzer-security.insecureAPI.DeprecatedOrUnsafeBufferHandling]
}
}
}
} else if (type == MDNS_TYPE_SRV) {
mdns_result_t *result = NULL;
Expand Down Expand Up @@ -4161,6 +4246,21 @@ void mdns_parse_packet(mdns_rx_packet_t *packet)
}
free(question);
}
while (parsed_packet->records) {
mdns_parsed_record_t *record = parsed_packet->records;
parsed_packet->records = parsed_packet->records->next;
if (record->host) {
free(record->host);
}
if (record->service) {
free(record->service);
}
if (record->proto) {
free(record->proto);
}
record->next = NULL;
free(record);
}
free(parsed_packet);
if (browse_result_instance) {
free(browse_result_instance);
Expand Down

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