Merge "Add evaluate domain name callback in DnsResolver" (c20becb3) · Commits · e / os / android_packages_modules_DnsResolver

DnsProxyListener.cpp

+25 −5

Original line number	Diff line number	Diff line
		@@ -535,6 +535,13 @@ DnsProxyListener::GetAddrInfoHandler::~GetAddrInfoHandler() {
		free(mHints);
		}

		static bool evaluate_domain_name(const android_net_context &netcontext,
		const char *host) {
		if (!gResNetdCallbacks.evaluate_domain_name)
		return true;
		return gResNetdCallbacks.evaluate_domain_name(netcontext, host);
		}

		static bool sendBE32(SocketClient* c, uint32_t data) {
		uint32_t be_data = htonl(data);
		return c->sendData(&be_data, sizeof(be_data)) == 0;
		@@ -672,7 +679,12 @@ void DnsProxyListener::GetAddrInfoHandler::run() {
		NetworkDnsEventReported event;
		initDnsEvent(&event);
		if (queryLimiter.start(uid)) {
		rv = resolv_getaddrinfo(mHost, mService, mHints, &mNetContext, &result, &event);
		if (evaluate_domain_name(mNetContext, mHost)) {
		rv = resolv_getaddrinfo(mHost, mService, mHints, &mNetContext, &result,
		&event);
		} else {
		rv = EAI_SYSTEM;
		}
		queryLimiter.finish(uid);
		} else {
		// Note that this error code is currently not passed down to the client.
		@@ -887,8 +899,12 @@ void DnsProxyListener::ResNSendHandler::run() {
		NetworkDnsEventReported event;
		initDnsEvent(&event);
		if (queryLimiter.start(uid)) {
		if (evaluate_domain_name(mNetContext, rr_name.c_str())) {
		nsendAns = resolv_res_nsend(&mNetContext, msg.data(), msgLen, ansBuf.data(), MAXPACKET,
		&rcode, static_cast<ResNsendFlags>(mFlags), &event);
		} else {
		nsendAns = -EAI_SYSTEM;
		}
		queryLimiter.finish(uid);
		} else {
		LOG(WARNING) << "ResNSendHandler::run: resnsend: from UID " << uid
		@@ -1080,8 +1096,12 @@ void DnsProxyListener::GetHostByNameHandler::run() {
		NetworkDnsEventReported event;
		initDnsEvent(&event);
		if (queryLimiter.start(uid)) {
		if (evaluate_domain_name(mNetContext, mName)) {
		rv = resolv_gethostbyname(mName, mAf, &hbuf, tmpbuf, sizeof tmpbuf, &mNetContext, &hp,
		&event);
		} else {
		rv = EAI_SYSTEM;
		}
		queryLimiter.finish(uid);
		} else {
		rv = EAI_MEMORY;

DnsResolver.cpp

+1 −0

Original line number	Diff line number	Diff line
		@@ -38,6 +38,7 @@ bool resolv_init(const ResolverNetdCallbacks* callbacks) {
		gResNetdCallbacks.log = callbacks->log;
		if (gApiLevel >= 30) {
		gResNetdCallbacks.tagSocket = callbacks->tagSocket;
		gResNetdCallbacks.evaluate_domain_name = callbacks->evaluate_domain_name;
		}
		android::net::gDnsResolv = android::net::DnsResolver::getInstance();
		return android::net::gDnsResolv->start();

include/netd_resolv/resolv.h

+24 −0

Original line number	Diff line number	Diff line
		@@ -81,6 +81,29 @@ typedef void (*get_network_context_callback)(unsigned netid, uid_t uid,
		typedef void (log_callback)(const char msg);
		typedef int (*tagSocketCallback)(int sockFd, uint32_t tag, uid_t uid, pid_t pid);

		// The DnsResolver module invokes this callback once before starting each DNS
		// lookup. The callback receives the android_net_context associated with the
		// request, and the (possibly unqualified) hostname requested by the app via
		// getaddrinfo() or gethostbyname().
		//
		// If the callback returns false, the DnsResolver will abort the request
		// returning EAI_SYSTEM. If the callback returns true, the query will proceed as
		// usual.
		//
		// If this callback is not present (i.e. set to nullptr), the effect is the same
		// of returning true.
		//
		// This callback will be invoked concurrently from multiple threads. It must
		// peform its own locking when accessing shared data structures. Furthermore,
		// the callback must not sleep nor perform RPC requests.
		//
		// Be mindful that hostnames could contain sensitive user data. Do not log them
		// and do not transmit them to third parties without explicit user
		// authorization.
		//
		typedef bool (*evaluate_domain_name_callback)(
		const android_net_context &netcontext, const char *host);

		/*
		* Some functions needed by the resolver (e.g. checkCallingPermission()) live in
		* libraries with no ABI stability guarantees, such as libbinder.so.
		@@ -92,6 +115,7 @@ struct ResolverNetdCallbacks {
		get_network_context_callback get_network_context;
		log_callback log;
		tagSocketCallback tagSocket;
		evaluate_domain_name_callback evaluate_domain_name;
		};

		#define TAG_SYSTEM_DNS 0xFFFFFF82