| 329 | } |
| 330 | |
| 331 | std::string setCustomDnsWhileConnected(const std::string &pars) |
| 332 | { |
| 333 | unsigned long ifIndex; |
| 334 | std::wstring overrideDnsIpAddress; |
| 335 | deserializePars(pars, ifIndex, overrideDnsIpAddress); |
| 336 | |
| 337 | if (!NetworkValidation::isValidIpAddress(overrideDnsIpAddress)) { |
| 338 | spdlog::error(L"setCustomDnsWhileConnected: invalid IP address: \"{}\"", overrideDnsIpAddress); |
| 339 | return serializeResult(false); |
| 340 | } |
| 341 | |
| 342 | // Prefer the structured SetInterfaceDnsSettings API (Win10 2004+) so the IP is passed |
| 343 | // through a typed field instead of being interpolated into a command line. The IP is |
| 344 | // validated above, so command injection isn't reachable today, but the typed call |
| 345 | // closes the netsh parsing sink entirely as defense-in-depth. |
| 346 | try { |
| 347 | wsl::SystemLibLoader iphlpapi("iphlpapi.dll"); |
| 348 | const auto pSetInterfaceDnsSettings = iphlpapi.getFunction<DWORD WINAPI(GUID, const DNS_INTERFACE_SETTINGS *)>("SetInterfaceDnsSettings"); |
| 349 | |
| 350 | NET_LUID luid = {}; |
| 351 | DWORD ret = ::ConvertInterfaceIndexToLuid(ifIndex, &luid); |
| 352 | if (ret != NO_ERROR) { |
| 353 | spdlog::error("setCustomDnsWhileConnected: ConvertInterfaceIndexToLuid failed ({})", ret); |
| 354 | return serializeResult(false); |
| 355 | } |
| 356 | |
| 357 | GUID guid = {}; |
| 358 | ret = ::ConvertInterfaceLuidToGuid(&luid, &guid); |
| 359 | if (ret != NO_ERROR) { |
| 360 | spdlog::error("setCustomDnsWhileConnected: ConvertInterfaceLuidToGuid failed ({})", ret); |
| 361 | return serializeResult(false); |
| 362 | } |
| 363 | |
| 364 | IN6_ADDR addr6; |
| 365 | const bool isV6 = (::InetPtonW(AF_INET6, overrideDnsIpAddress.c_str(), &addr6) == 1); |
| 366 | |
| 367 | // DNS_INTERFACE_SETTINGS::NameServer is PWSTR; copy into a non-const buffer so we |
| 368 | // don't const_cast away the std::wstring's immutability. |
| 369 | std::wstring nameServer = overrideDnsIpAddress; |
| 370 | DNS_INTERFACE_SETTINGS settings = {}; |
| 371 | settings.Version = DNS_INTERFACE_SETTINGS_VERSION1; |
| 372 | settings.Flags = DNS_SETTING_NAMESERVER | (isV6 ? DNS_SETTING_IPV6 : 0); |
| 373 | settings.NameServer = nameServer.data(); |
| 374 | |
| 375 | ret = pSetInterfaceDnsSettings(guid, &settings); |
| 376 | if (ret != NO_ERROR) { |
| 377 | spdlog::error(L"setCustomDnsWhileConnected: SetInterfaceDnsSettings failed for ifIndex={} dns=\"{}\" ({})", ifIndex, overrideDnsIpAddress, ret); |
| 378 | return serializeResult(false); |
| 379 | } |
| 380 | |
| 381 | spdlog::debug(L"setCustomDnsWhileConnected: ifIndex={} dns={}", ifIndex, overrideDnsIpAddress); |
| 382 | return serializeResult(true); |
| 383 | } |
| 384 | catch (const std::system_error &ex) { |
| 385 | // SetInterfaceDnsSettings unavailable on this OS — fall through to the netsh path below. |
| 386 | spdlog::debug("setCustomDnsWhileConnected: SetInterfaceDnsSettings API unavailable ({}), falling back to netsh", ex.what()); |
| 387 | } |
| 388 |
nothing calls this directly
no test coverage detected