Make resolv_gethostbyaddr() re-entrant (324f9f8c) · Commits · e / os / android_packages_modules_DnsResolver

DnsProxyListener.cpp

+12 −8

Original line number	Original line	Diff line number	Diff line
	@@ -1186,7 +1186,9 @@ DnsProxyListener::GetHostByAddrHandler::~GetHostByAddrHandler() {
	free(mAddress);		free(mAddress);
	}		}

	void DnsProxyListener::GetHostByAddrHandler::doDns64ReverseLookup(struct hostent** hpp,		void DnsProxyListener::GetHostByAddrHandler::doDns64ReverseLookup(hostent* hbuf, char* buf,
			size_t buflen,
			struct hostent** hpp,
	NetworkDnsEventReported* event) {		NetworkDnsEventReported* event) {
	if (*hpp != nullptr \|\| mAddressFamily != AF_INET6 \|\| !mAddress) {		if (*hpp != nullptr \|\| mAddressFamily != AF_INET6 \|\| !mAddress) {
	return;		return;
	@@ -1215,14 +1217,14 @@ void DnsProxyListener::GetHostByAddrHandler::doDns64ReverseLookup(struct hostent
	if (queryLimiter.start(uid)) {		if (queryLimiter.start(uid)) {
	// Remove NAT64 prefix and do reverse DNS query		// Remove NAT64 prefix and do reverse DNS query
	struct in_addr v4addr = {.s_addr = v6addr.s6_addr32[3]};		struct in_addr v4addr = {.s_addr = v6addr.s6_addr32[3]};
	android_gethostbyaddrfornetcontext(&v4addr, sizeof(v4addr), AF_INET, &mNetContext, hpp,		resolv_gethostbyaddr(&v4addr, sizeof(v4addr), AF_INET, hbuf, buf, buflen, &mNetContext, hpp,
	event);		event);
	queryLimiter.finish(uid);		queryLimiter.finish(uid);
	if (*hpp) {		if (*hpp) {
	// Replace IPv4 address with original queried IPv6 address in place. The space has		// Replace IPv4 address with original queried IPv6 address in place. The space has
	// reserved by dns_gethtbyaddr() and netbsd_gethostent_r() in		// reserved by dns_gethtbyaddr() and netbsd_gethostent_r() in
	// system/netd/resolv/gethnamaddr.cpp.		// system/netd/resolv/gethnamaddr.cpp.
	// Note that android_gethostbyaddrfornetcontext returns only one entry in result.		// Note that resolv_gethostbyaddr() returns only one entry in result.
	memcpy((*hpp)->h_addr_list[0], &v6addr, sizeof(v6addr));		memcpy((*hpp)->h_addr_list[0], &v6addr, sizeof(v6addr));
	(*hpp)->h_addrtype = AF_INET6;		(*hpp)->h_addrtype = AF_INET6;
	(*hpp)->h_length = sizeof(struct in6_addr);		(*hpp)->h_length = sizeof(struct in6_addr);
	@@ -1237,12 +1239,14 @@ void DnsProxyListener::GetHostByAddrHandler::run() {
	maybeFixupNetContext(&mNetContext);		maybeFixupNetContext(&mNetContext);
	const uid_t uid = mClient->getUid();		const uid_t uid = mClient->getUid();
	hostent* hp = nullptr;		hostent* hp = nullptr;
			hostent hbuf;
			char tmpbuf[MAXPACKET];
	int32_t rv = 0;		int32_t rv = 0;
	NetworkDnsEventReported event;		NetworkDnsEventReported event;
	initDnsEvent(&event);		initDnsEvent(&event);
	if (queryLimiter.start(uid)) {		if (queryLimiter.start(uid)) {
	rv = android_gethostbyaddrfornetcontext(mAddress, mAddressLen, mAddressFamily, &mNetContext,		rv = resolv_gethostbyaddr(mAddress, mAddressLen, mAddressFamily, &hbuf, tmpbuf,
	&hp, &event);		sizeof tmpbuf, &mNetContext, &hp, &event);
	queryLimiter.finish(uid);		queryLimiter.finish(uid);
	} else {		} else {
	rv = EAI_MEMORY;		rv = EAI_MEMORY;
	@@ -1250,12 +1254,12 @@ void DnsProxyListener::GetHostByAddrHandler::run() {
	<< ", max concurrent queries reached";		<< ", max concurrent queries reached";
	}		}

	doDns64ReverseLookup(&hp, &event);		doDns64ReverseLookup(&hbuf, tmpbuf, sizeof tmpbuf, &hp, &event);
	const int32_t latencyUs = saturate_cast<int32_t>(s.timeTakenUs());		const int32_t latencyUs = saturate_cast<int32_t>(s.timeTakenUs());
	event.set_latency_micros(latencyUs);		event.set_latency_micros(latencyUs);
	event.set_event_type(EVENT_GETHOSTBYADDR);		event.set_event_type(EVENT_GETHOSTBYADDR);

	LOG(DEBUG) << "GetHostByAddrHandler::run: result: " << (hp ? "success" : gai_strerror(rv));		LOG(DEBUG) << "GetHostByAddrHandler::run: result: " << gai_strerror(rv);

	bool success = true;		bool success = true;
	if (hp) {		if (hp) {

DnsProxyListener.h

+2 −1

Original line number	Original line	Diff line number	Diff line
	@@ -111,7 +111,8 @@ class DnsProxyListener : public FrameworkListener {
	std::string threadName();		std::string threadName();

	private:		private:
	void doDns64ReverseLookup(hostent** hpp, NetworkDnsEventReported* event);		void doDns64ReverseLookup(hostent* hbuf, char* buf, size_t buflen, hostent** hpp,
			NetworkDnsEventReported* event);

	SocketClient* mClient; // ref counted		SocketClient* mClient; // ref counted
	void* mAddress; // address to lookup; owned		void* mAddress; // address to lookup; owned

gethnamaddr.cpp

+4 −40

Original line number	Original line	Diff line number	Diff line
	@@ -117,14 +117,6 @@ static int dns_gethtbyaddr(const unsigned char* uaddr, int len, int af,
	NetworkDnsEventReported* event);		NetworkDnsEventReported* event);
	static int dns_gethtbyname(const char* name, int af, getnamaddr* info);		static int dns_gethtbyname(const char* name, int af, getnamaddr* info);

	static int android_gethostbyaddrfornetcontext_proxy_internal(const void*, socklen_t, int,
	struct hostent, char, size_t,
	const struct android_net_context*,
	NetworkDnsEventReported* event);
	static int android_gethostbyaddrfornetcontext_proxy(const void* addr, socklen_t len, int af,
	const struct android_net_context* netcontext,
	hostent** hp, NetworkDnsEventReported* event);

	#define BOUNDED_INCR(x) \		#define BOUNDED_INCR(x) \
	do { \		do { \
	BOUNDS_CHECK(cp, x); \		BOUNDS_CHECK(cp, x); \
	@@ -483,10 +475,9 @@ fake:
	return 0;		return 0;
	}		}

	static int android_gethostbyaddrfornetcontext_real(const void* addr, socklen_t len, int af,		int resolv_gethostbyaddr(const void* addr, socklen_t len, int af, hostent* hp, char* buf,
	struct hostent* hp, char* buf, size_t buflen,		size_t buflen, const struct android_net_context* netcontext,
	const struct android_net_context* netcontext,		hostent** result, NetworkDnsEventReported* event) {
	NetworkDnsEventReported* event) {
	const uint8_t* uaddr = (const uint8_t*)addr;		const uint8_t* uaddr = (const uint8_t*)addr;
	socklen_t size;		socklen_t size;
	struct getnamaddr info;		struct getnamaddr info;
	@@ -531,16 +522,10 @@ static int android_gethostbyaddrfornetcontext_real(const void* addr, socklen_t l
	int error = dns_gethtbyaddr(uaddr, len, af, netcontext, &info, event);		int error = dns_gethtbyaddr(uaddr, len, af, netcontext, &info, event);
	if (error != 0) return error;		if (error != 0) return error;
	}		}
			*result = hp;
	return 0;		return 0;
	}		}

	static int android_gethostbyaddrfornetcontext_proxy_internal(
	const void* addr, socklen_t len, int af, struct hostent* hp, char* hbuf, size_t hbuflen,
	const struct android_net_context* netcontext, NetworkDnsEventReported* event) {
	return android_gethostbyaddrfornetcontext_real(addr, len, af, hp, hbuf, hbuflen, netcontext,
	event);
	}

	// TODO: Consider leaving function without returning error code as _gethtent() does because		// TODO: Consider leaving function without returning error code as _gethtent() does because
	// the error code of the caller does not currently return to netd.		// the error code of the caller does not currently return to netd.
	struct hostent* netbsd_gethostent_r(FILE* hf, struct hostent* hent, char* buf, size_t buflen,		struct hostent* netbsd_gethostent_r(FILE* hf, struct hostent* hent, char* buf, size_t buflen,
	@@ -584,9 +569,6 @@ struct hostent* netbsd_gethostent_r(FILE* hf, struct hostent* hent, char* buf, s
	len = NS_IN6ADDRSZ;		len = NS_IN6ADDRSZ;
	} else {		} else {
	if (inet_pton(AF_INET, p, &host_addr) <= 0) continue;		if (inet_pton(AF_INET, p, &host_addr) <= 0) continue;

	res_state res = res_get_state();
	if (res == NULL) goto nospc;
	af = AF_INET;		af = AF_INET;
	len = NS_INADDRSZ;		len = NS_INADDRSZ;
	}		}
	@@ -787,24 +769,6 @@ nospc:
	return EAI_MEMORY;		return EAI_MEMORY;
	}		}

	int android_gethostbyaddrfornetcontext(const void* addr, socklen_t len, int af,
	const struct android_net_context* netcontext, hostent** hp,
	NetworkDnsEventReported* event) {
	return android_gethostbyaddrfornetcontext_proxy(addr, len, af, netcontext, hp, event);
	}

	static int android_gethostbyaddrfornetcontext_proxy(const void* addr, socklen_t len, int af,
	const struct android_net_context* netcontext,
	hostent** hp, NetworkDnsEventReported* event) {
	assert(event != nullptr);

	struct res_static* rs = res_get_static(); // For thread-safety.
	int error = android_gethostbyaddrfornetcontext_proxy_internal(
	addr, len, af, &rs->host, rs->hostbuf, sizeof(rs->hostbuf), netcontext, event);
	if (error == 0) *hp = &rs->host;
	return error;
	}

	int herrnoToAiErrno(int he) {		int herrnoToAiErrno(int he) {
	switch (he) {		switch (he) {
	// extended h_errno		// extended h_errno

gethnamaddr.h

+4 −3

Original line number	Original line	Diff line number	Diff line
	@@ -30,8 +30,9 @@
	// This is the entry point for the gethostbyname() family of legacy calls.		// This is the entry point for the gethostbyname() family of legacy calls.
	int resolv_gethostbyname(const char* name, int af, hostent* hp, char* buf, size_t buflen,		int resolv_gethostbyname(const char* name, int af, hostent* hp, char* buf, size_t buflen,
	const android_net_context* netcontext, hostent** result,		const android_net_context* netcontext, hostent** result,
	android::net::NetworkDnsEventReported*);		android::net::NetworkDnsEventReported* event);

	// This is the entry point for the gethostbyaddr() family of legacy calls.		// This is the entry point for the gethostbyaddr() family of legacy calls.
	int android_gethostbyaddrfornetcontext(const void, socklen_t, int, const android_net_context,		int resolv_gethostbyaddr(const void* addr, socklen_t len, int af, hostent* hp, char* buf,
	hostent*, android::net::NetworkDnsEventReported);		size_t buflen, const android_net_context* netcontext, hostent** result,
			android::net::NetworkDnsEventReported* event);

resolv_unit_test.cpp

+1 −1

Original line number	Original line	Diff line number	Diff line
	@@ -968,7 +968,7 @@ TEST_F(GetHostByNameForNetContextTest, CnamesInfiniteLoop) {
	// - Invalid length CNAME, or QNAME.		// - Invalid length CNAME, or QNAME.
	// - Unexpected amount of questions.		// - Unexpected amount of questions.
	// - CNAME RDATA with the domain name which has null label(s).		// - CNAME RDATA with the domain name which has null label(s).
	// TODO: Add test for android_gethostbyaddrfornetcontext().		// TODO: Add test for resolv_gethostbyaddr().

	} // end of namespace net		} // end of namespace net
	} // end of namespace android		} // end of namespace android