init: more unique_fd, less goto (7c4609cf) · Commits · e / os / android_system_core

init/init.cpp

+29 −49

Original line number	Diff line number	Diff line
		@@ -73,6 +73,7 @@ using namespace std::string_literals;
		using android::base::boot_clock;
		using android::base::GetProperty;
		using android::base::Timer;
		using android::base::unique_fd;

		namespace android {
		namespace init {
		@@ -291,65 +292,49 @@ static int wait_for_coldboot_done_action(const std::vector<std::string>& args) {
		* time. We do not reboot or halt on failures, as this is a best-effort
		* attempt.
		*/
		static int mix_hwrng_into_linux_rng_action(const std::vector<std::string>& args)
		{
		int result = -1;
		int hwrandom_fd = -1;
		int urandom_fd = -1;
		char buf[512];
		ssize_t chunk_size;
		size_t total_bytes_written = 0;

		hwrandom_fd = TEMP_FAILURE_RETRY(
		open("/dev/hw_random", O_RDONLY \| O_NOFOLLOW \| O_CLOEXEC));
		static int mix_hwrng_into_linux_rng_action(const std::vector<std::string>& args) {
		unique_fd hwrandom_fd(
		TEMP_FAILURE_RETRY(open("/dev/hw_random", O_RDONLY \| O_NOFOLLOW \| O_CLOEXEC)));
		if (hwrandom_fd == -1) {
		if (errno == ENOENT) {
		LOG(ERROR) << "/dev/hw_random not found";
		LOG(INFO) << "/dev/hw_random not found";
		// It's not an error to not have a Hardware RNG.
		result = 0;
		} else {
		PLOG(ERROR) << "Failed to open /dev/hw_random";
		return 0;
		}
		goto ret;
		PLOG(ERROR) << "Failed to open /dev/hw_random";
		return -1;
		}

		urandom_fd = TEMP_FAILURE_RETRY(
		open("/dev/urandom", O_WRONLY \| O_NOFOLLOW \| O_CLOEXEC));
		unique_fd urandom_fd(
		TEMP_FAILURE_RETRY(open("/dev/urandom", O_WRONLY \| O_NOFOLLOW \| O_CLOEXEC)));
		if (urandom_fd == -1) {
		PLOG(ERROR) << "Failed to open /dev/urandom";
		goto ret;
		return -1;
		}

		char buf[512];
		size_t total_bytes_written = 0;
		while (total_bytes_written < sizeof(buf)) {
		chunk_size = TEMP_FAILURE_RETRY(
		read(hwrandom_fd, buf, sizeof(buf) - total_bytes_written));
		ssize_t chunk_size =
		TEMP_FAILURE_RETRY(read(hwrandom_fd, buf, sizeof(buf) - total_bytes_written));
		if (chunk_size == -1) {
		PLOG(ERROR) << "Failed to read from /dev/hw_random";
		goto ret;
		return -1;
		} else if (chunk_size == 0) {
		LOG(ERROR) << "Failed to read from /dev/hw_random: EOF";
		goto ret;
		return -1;
		}

		chunk_size = TEMP_FAILURE_RETRY(write(urandom_fd, buf, chunk_size));
		if (chunk_size == -1) {
		PLOG(ERROR) << "Failed to write to /dev/urandom";
		goto ret;
		return -1;
		}
		total_bytes_written += chunk_size;
		}

		LOG(INFO) << "Mixed " << total_bytes_written << " bytes from /dev/hw_random into /dev/urandom";
		result = 0;

		ret:
		if (hwrandom_fd != -1) {
		close(hwrandom_fd);
		}
		if (urandom_fd != -1) {
		close(urandom_fd);
		}
		return result;
		return 0;
		}

		static void security_failure() {
		@@ -425,45 +410,40 @@ static bool __attribute__((unused)) set_mmap_rnd_bits_min(int start, int min, bo
		* ec9ee4acd97c drivers: char: random: add get_random_long()
		* 5ef11c35ce86 mm: ASLR: use get_random_long()
		*/
		static int set_mmap_rnd_bits_action(const std::vector<std::string>& args)
		{
		int ret = -1;

		static int set_mmap_rnd_bits_action(const std::vector<std::string>& args) {
		/* values are arch-dependent */
		#if defined(USER_MODE_LINUX)
		/* uml does not support mmap_rnd_bits */
		ret = 0;
		return 0;
		#elif defined(__aarch64__)
		/* arm64 supports 18 - 33 bits depending on pagesize and VA_SIZE */
		if (set_mmap_rnd_bits_min(33, 24, false)
		&& set_mmap_rnd_bits_min(16, 16, true)) {
		ret = 0;
		return 0;
		}
		#elif defined(__x86_64__)
		/* x86_64 supports 28 - 32 bits */
		if (set_mmap_rnd_bits_min(32, 32, false)
		&& set_mmap_rnd_bits_min(16, 16, true)) {
		ret = 0;
		return 0;
		}
		#elif defined(__arm__) \|\| defined(__i386__)
		/* check to see if we're running on 64-bit kernel */
		bool h64 = !access(MMAP_RND_COMPAT_PATH, F_OK);
		/* supported 32-bit architecture must have 16 bits set */
		if (set_mmap_rnd_bits_min(16, 16, h64)) {
		ret = 0;
		return 0;
		}
		#elif defined(__mips__) \|\| defined(__mips64__)
		// TODO: add mips support b/27788820
		ret = 0;
		return 0;
		#else
		LOG(ERROR) << "Unknown architecture";
		#endif

		if (ret == -1) {
		LOG(ERROR) << "Unable to set adequate mmap entropy value!";
		security_failure();
		}
		return ret;
		return -1;
		}

		#define KPTR_RESTRICT_PATH "/proc/sys/kernel/kptr_restrict"