Use client-server processing to avoid constant super-user invocation.

Architecture.cpp

@@ -0,0 +1,25 @@
+/*
+U2FDevice - A program to allow Raspberry Pi Zeros to act as U2F tokens
+Copyright (C) 2018  Michael Kuc
+
+This program is free software: you can redistribute it and/or modify
+it under the terms of the GNU General Public License as published by
+the Free Software Foundation, either version 3 of the License, or
+(at your option) any later version.
+
+This program is distributed in the hope that it will be useful,
+but WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+GNU General Public License for more details.
+
+You should have received a copy of the GNU General Public License
+along with this program.  If not, see <https://www.gnu.org/licenses/>.
+*/
+
+#include "_Architecture.hpp"
+
+using namespace std;
+
+#if ARCHITECTURE == ARCH_ANDROID
+string hidDev = "/dev/hidg2";
+#endif

Architecture.hpp

@@ -18,22 +18,7 @@ along with this program.  If not, see <https://www.gnu.org/licenses/>.
 
 #pragma once
 
-#define ARCH_RASPBERRY_PI 1
+#include "_Architecture.hpp"
-#define ARCH_ANDROID 2
-#define ARCHITECTURE ARCH_ANDROID
-
-#if ARCHITECTURE == ARCH_RASPBERRY_PI
-#	define STORAGE_PREFIX "/usr/share/"
-#	define HID_DEV "/dev/hidg0"
-#	define DEBUG_STREAMS "/tmp/"
-//	#define DEBUG_MSGS
-#	define LEDS
-#elif ARCHITECTURE == ARCH_ANDROID
-#	define STORAGE_PREFIX "/sdcard/U2F/"
-#	define HID_DEV "/dev/hidg2"
-#	define DEBUG_STREAMS "/data/local/tmp/"
-// #define DEBUG_MSGS
-#endif
 
 #undef ARCH_ANDROID
 #undef ARCH_RASPBERRY_PI

IO.cpp

@@ -29,9 +29,11 @@ along with this program.  If not, see <https://www.gnu.org/licenses/>.
 #include <fcntl.h>
 #include <iostream>
 #include <memory>
+#include <poll.h>
 #include <ratio>
 #include <stdexcept>
 #include <string>
+#include <sys/socket.h>
 #include <sys/stat.h>
 #include <sys/types.h>
 #include <unistd.h>
@@ -41,12 +43,13 @@ using namespace std;
 bool bytesAvailable(size_t count);
 vector<uint8_t>& getBuffer();
 
-string binaryDirectory{};
+#ifdef DEBUG_STREAMS
 string cacheDirectory{ DEBUG_STREAMS };
+#endif
 
-// Thanks to https://stackoverflow.com/a/478960
+#ifdef HID_SOCKET
-vector<uint8_t> execOutput(const string& cmd);
+string clientSocket{};
-void execInput(const string& cmd, const vector<uint8_t>& stdinData);
+#endif
 
 vector<uint8_t> readNonBlock(const size_t count) {
 	if (!bytesAvailable(count))
@@ -63,13 +66,25 @@ vector<uint8_t> readNonBlock(const size_t count) {
 }
 
 void write(const vector<uint8_t>& bytes) {
-	__android_log_print(ANDROID_LOG_DEBUG, "U2FAndroid", "Writing %zu bytes", bytes.size());
+	size_t totalBytes = 0;
-	execInput("su -c \"" + binaryDirectory + "/U2FAndroid_Write\"", bytes);
+	auto hostDescriptor = *getHostDescriptor();
+
+	while (totalBytes < bytes.size()) {
+		auto writtenBytes =
+		    send(hostDescriptor, bytes.data() + totalBytes, bytes.size() - totalBytes, 0);
+
+		if (writtenBytes > 0)
+			totalBytes += writtenBytes;
+		else if (errno != 0 && errno != EAGAIN &&
+		         errno != EWOULDBLOCK) // Expect file blocking behaviour
+			ERR();
+	}
+
+	errno = 0;
 }
 
 bool bytesAvailable(const size_t count) {
 	auto startTime = std::chrono::high_resolution_clock::now();
-	const timespec iterDelay{ 0, 10000000 };
 	chrono::duration<double, milli> delay{ 0 };
 
 	while (delay.count() < U2FHID_TRANS_TIMEOUT) {
@@ -79,7 +94,6 @@ bool bytesAvailable(const size_t count) {
 #endif
 			return true;
 		}
-		nanosleep(&iterDelay, nullptr);
 		delay = chrono::high_resolution_clock::now() - startTime;
 	}
 
@@ -96,44 +110,49 @@ vector<uint8_t>& bufferVar() {
 }
 
 vector<uint8_t>& getBuffer() {
-	auto& buff = bufferVar();
+	const timespec delay{ 0, 10'000'000 };
-	vector<uint8_t> bytes = execOutput("su -c \"" + binaryDirectory + "/U2FAndroid_Read\"");
 
-	if (!bytes.empty()) {
+	auto& buff = bufferVar();
-		__android_log_print(ANDROID_LOG_DEBUG, "U2FAndroid", "Reading bytes: got %zu",
+	array<uint8_t, HID_RPT_SIZE> bytes{};
-		                    bytes.size());
+	auto hostDescriptor = *getHostDescriptor();
-		buff.insert(buff.end(), bytes.begin(), bytes.end());
+
+	pollfd pFD{ hostDescriptor, POLLIN };
+
+	while (true) {
+		ppoll(&pFD, 1, &delay, 0);
+
+		if (pFD.revents & POLLIN) {
+			auto readByteCount = recv(hostDescriptor, bytes.data(), HID_RPT_SIZE, 0);
+
+			if (readByteCount > 0 && readByteCount != HID_RPT_SIZE) {
+				// Failed to copy an entire packet in, so log this packet
+#ifdef DEBUG_MSGS
+				cerr << "Only retrieved " << readByteCount << " bytes from expected full packet."
+				     << endl;
+#endif
+			}
+
+			if (readByteCount > 0) {
+				copy(bytes.begin(), bytes.begin() + readByteCount, back_inserter(buff));
 
 #ifdef DEBUG_STREAMS
-		fwrite(bytes.data(), 1, bytes.size(), getComHostStream().get());
+				fwrite(bytes.data(), 1, readByteCount, getComHostStream().get());
 #endif
+
+			} else if (errno != EAGAIN && errno != EWOULDBLOCK) // Expect read would block
+			{
+				ERR();
+#ifdef DEBUG_MSGS
+				cerr << "Unknown stream error: " << errno << endl;
+#endif
+				break;
+			} else {
+				errno = 0;
+				break; // Escape loop if blocking would occur
+			}
+		} else
+			break;
 	}
 
 	return buff;
 }
-
-vector<uint8_t> execOutput(const string& cmd) {
-	// NOLINT(hicpp-member-init)
-	array<char, HID_RPT_SIZE> buffer;
-	vector<uint8_t> result{};
-	unique_ptr<FILE, decltype(&pclose)> pipe{ popen(cmd.c_str(), "rb"), pclose };
-
-	if (!pipe)
-		throw std::runtime_error("popen() failed!");
-	while (size_t readBytes = fread(buffer.data(), 1, buffer.size(), pipe.get()))
-		copy(buffer.begin(), buffer.begin() + readBytes, back_inserter(result));
-
-	return result;
-}
-
-void execInput(const string& cmd, const vector<uint8_t>& stdinData) {
-	assert(stdinData.size() % HID_RPT_SIZE == 0);
-
-	size_t writtenBytes = 0;
-	unique_ptr<FILE, decltype(&pclose)> pipe{ popen(cmd.c_str(), "wb"), pclose };
-
-	if (!pipe)
-		throw std::runtime_error("popen() failed!");
-	while (writtenBytes < stdinData.size())
-		writtenBytes += fwrite(stdinData.data(), 1, HID_RPT_SIZE, pipe.get());
-}

IO.hpp

@@ -21,8 +21,13 @@ along with this program.  If not, see <https://www.gnu.org/licenses/>.
 #include <cstdint>
 #include <vector>
 
-extern std::string binaryDirectory;
+#ifdef DEBUG_STREAMS
 extern std::string cacheDirectory;
+#endif
+
+#ifdef HID_SOCKET
+extern std::string clientSocket;
+#endif
 
 // Returns either the number of bytes specified,
 // or returns empty vector without discarding bytes from HID stream

Streams.cpp

@@ -17,36 +17,46 @@ along with this program.  If not, see <https://www.gnu.org/licenses/>.
 */
 
 #include "Streams.hpp"
+#include "Architecture.hpp"
 #include "IO.hpp"
+#include <android/log.h>
 #include <cstdio>
 #include <fcntl.h>
 #include <iostream>
+#include <sys/socket.h>
 #include <sys/stat.h>
 #include <sys/types.h>
+#include <sys/un.h>
 #include <unistd.h>
 
-using namespace std;
+using std::cerr;
+using std::clog;
+using std::endl;
+using std::runtime_error;
+using std::shared_ptr;
+using std::string;
+
+int initialiseHostDescriptor();
 
 #ifdef DEBUG_STREAMS
+
 FILE* initHTML(FILE* fPtr, const string& title);
+
 void closeHTML(FILE* fPtr);
+
 #endif
 
 shared_ptr<int> getHostDescriptor() {
-	static shared_ptr<int> descriptor{};
+	static shared_ptr<int> descriptor{ new int{ initialiseHostDescriptor() }, [](const int* fd) {
-
+		                                  close(*fd);
-	descriptor.reset(new int{ open(HID_DEV, O_RDWR | O_NONBLOCK | O_APPEND) }, [](int* fd) {
+		                                  delete fd;
-		close(*fd);
+		                              } };
-		delete fd;
-	});
-
-	if (*descriptor == -1)
-		throw runtime_error{ "Descriptor is unavailable" };
 
 	return descriptor;
 }
 
 #ifdef DEBUG_STREAMS
+
 shared_ptr<FILE> getComHostStream() {
 	static shared_ptr<FILE> stream{ fopen((cacheDirectory + "comhost.txt").c_str(), "wb"),
 		                            [](FILE* f) {
@@ -182,4 +192,49 @@ void closeHTML(FILE* fPtr) {
 	              "</html>");
 	fclose(fPtr);
 }
+
 #endif
+
+int initialiseHostDescriptor() {
+	int descriptor;
+
+#ifdef HID_SOCKET
+	descriptor = socket(AF_UNIX, SOCK_SEQPACKET | SOCK_CLOEXEC, 0);
+	if (descriptor == -1)
+		throw runtime_error{ "Unable to open client socket" };
+
+	sockaddr_un serverSockAddr{}, clientSockAddr{};
+
+	clientSockAddr.sun_family = AF_UNIX;
+	strncpy(clientSockAddr.sun_path, clientSocket.c_str(), sizeof(clientSockAddr.sun_path) - 1);
+
+	// Attempt to remove existing
+	unlink(clientSocket.c_str());
+
+	int result = ::bind(descriptor, (sockaddr*)&clientSockAddr, sizeof(clientSockAddr));
+	if (result == -1)
+		throw runtime_error{ "Unable to bind to client socket: " + clientSocket };
+
+	serverSockAddr.sun_family = AF_UNIX;
+	strncpy(serverSockAddr.sun_path, HID_DEV, sizeof(serverSockAddr.sun_path) - 1);
+
+	for (size_t connectCount = 0; connectCount < 100; connectCount++) {
+		result = connect(descriptor, (sockaddr*)&serverSockAddr, sizeof(serverSockAddr));
+		if (result != 1)
+			break;
+		usleep(100000);
+	}
+
+	if (result == -1)
+		throw runtime_error{ "Unable to connect to server socket: " + string{ HID_DEV } };
+
+	__android_log_print(ANDROID_LOG_DEBUG, "U2FDevice", "Connected to server");
+#else
+	descriptor = open(HID_DEV, O_RDWR | O_NONBLOCK | O_APPEND);
+
+	if (descriptor == -1)
+		throw runtime_error{ "Descriptor is unavailable" };
+#endif
+
+	return descriptor;
+}

_Architecture.hpp

@@ -0,0 +1,39 @@
+/*
+U2FDevice - A program to allow Raspberry Pi Zeros to act as U2F tokens
+Copyright (C) 2018  Michael Kuc
+
+This program is free software: you can redistribute it and/or modify
+it under the terms of the GNU General Public License as published by
+the Free Software Foundation, either version 3 of the License, or
+(at your option) any later version.
+
+This program is distributed in the hope that it will be useful,
+but WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+GNU General Public License for more details.
+
+You should have received a copy of the GNU General Public License
+along with this program.  If not, see <https://www.gnu.org/licenses/>.
+*/
+
+#pragma once
+
+#define ARCH_RASPBERRY_PI 1
+#define ARCH_ANDROID 2
+#define ARCHITECTURE ARCH_ANDROID
+
+#if ARCHITECTURE == ARCH_RASPBERRY_PI
+#	define STORAGE_PREFIX "/usr/share/"
+#	define HID_DEV "/dev/hidg0"
+#	define DEBUG_STREAMS "/tmp/"
+//	#define DEBUG_MSGS
+#	define LEDS
+#elif ARCHITECTURE == ARCH_ANDROID
+#	include <string>
+#	define STORAGE_PREFIX "/sdcard/U2F/"
+extern std::string hidDev;
+#	define HID_DEV hidDev.c_str()
+#	define DEBUG_STREAMS "/sdcard/log/"
+#	define HID_SOCKET
+// #define DEBUG_MSGS
+#endif