Merge "fs_mgr: overlayfs earlier kernels do not need override_creds=off" (678076cc) · Commits · e / os / android_system_core

fs_mgr/fs_mgr_overlayfs.cpp

+40 −9

Original line number	Diff line number	Diff line
		@@ -27,6 +27,7 @@
		#include <sys/stat.h>
		#include <sys/statvfs.h>
		#include <sys/types.h>
		#include <sys/utsname.h>
		#include <sys/vfs.h>
		#include <unistd.h>

		@@ -56,13 +57,17 @@ using namespace std::literals;
		using namespace android::dm;
		using namespace android::fs_mgr;

		static bool fs_mgr_access(const std::string& path) {
		namespace {

		bool fs_mgr_access(const std::string& path) {
		auto save_errno = errno;
		auto ret = access(path.c_str(), F_OK) == 0;
		errno = save_errno;
		return ret;
		}

		} // namespace

		#if ALLOW_ADBD_DISABLE_VERITY == 0 // If we are a user build, provide stubs

		bool fs_mgr_overlayfs_mount_all(fstab*) {
		@@ -218,9 +223,12 @@ const auto kUpperdirOption = "upperdir="s;
		std::string fs_mgr_get_overlayfs_options(const std::string& mount_point) {
		auto candidate = fs_mgr_get_overlayfs_candidate(mount_point);
		if (candidate.empty()) return "";

		return "override_creds=off," + kLowerdirOption + mount_point + "," + kUpperdirOption +
		candidate + kUpperName + ",workdir=" + candidate + kWorkName;
		auto ret = kLowerdirOption + mount_point + "," + kUpperdirOption + candidate + kUpperName +
		",workdir=" + candidate + kWorkName;
		if (fs_mgr_overlayfs_valid() == OverlayfsValidResult::kOverrideCredsRequired) {
		ret += ",override_creds=off";
		}
		return ret;
		}

		const char* fs_mgr_mount_point(const char* mount_point) {
		@@ -733,7 +741,7 @@ bool fs_mgr_overlayfs_scratch_can_be_mounted(const std::string& scratch_device)
		bool fs_mgr_overlayfs_mount_all(fstab* fstab) {
		auto ret = false;

		if (!fs_mgr_overlayfs_supports_override_creds()) return ret;
		if (fs_mgr_overlayfs_valid() == OverlayfsValidResult::kNotSupported) return ret;

		if (!fstab) return ret;

		@@ -791,7 +799,7 @@ std::vector<std::string> fs_mgr_overlayfs_required_devices(
		bool fs_mgr_overlayfs_setup(const char* backing, const char* mount_point, bool* change) {
		if (change) *change = false;
		auto ret = false;
		if (!fs_mgr_overlayfs_supports_override_creds()) return ret;
		if (fs_mgr_overlayfs_valid() == OverlayfsValidResult::kNotSupported) return ret;
		if (!fs_mgr_boot_completed()) {
		errno = EBUSY;
		PERROR << "setup";
		@@ -854,7 +862,7 @@ bool fs_mgr_overlayfs_teardown(const char* mount_point, bool* change) {
		for (const auto& overlay_mount_point : kOverlayMountPoints) {
		ret &= fs_mgr_overlayfs_teardown_one(overlay_mount_point, mount_point ?: "", change);
		}
		if (!fs_mgr_overlayfs_supports_override_creds()) {
		if (fs_mgr_overlayfs_valid() == OverlayfsValidResult::kNotSupported) {
		// After obligatory teardown to make sure everything is clean, but if
		// we didn't want overlayfs in the the first place, we do not want to
		// waste time on a reboot (or reboot request message).
		@@ -905,7 +913,30 @@ std::string fs_mgr_get_context(const std::string& mount_point) {
		return context;
		}

		bool fs_mgr_overlayfs_supports_override_creds() {
		OverlayfsValidResult fs_mgr_overlayfs_valid() {
		// Overlayfs available in the kernel, and patched for override_creds?
		return fs_mgr_access("/sys/module/overlay/parameters/override_creds");
		if (fs_mgr_access("/sys/module/overlay/parameters/override_creds")) {
		return OverlayfsValidResult::kOverrideCredsRequired;
		}
		if (!fs_mgr_access("/sys/module/overlay")) {
		return OverlayfsValidResult::kNotSupported;
		}
		struct utsname uts;
		if (uname(&uts) == -1) {
		return OverlayfsValidResult::kNotSupported;
		}
		int major, minor;
		if (sscanf(uts.release, "%d.%d", &major, &minor) != 2) {
		return OverlayfsValidResult::kNotSupported;
		}
		if (major < 4) {
		return OverlayfsValidResult::kOk;
		}
		if (major > 4) {
		return OverlayfsValidResult::kNotSupported;
		}
		if (minor > 6) {
		return OverlayfsValidResult::kNotSupported;
		}
		return OverlayfsValidResult::kOk;
		}

fs_mgr/fs_mgr_vendor_overlay.cpp

+5 −3

Original line number	Diff line number	Diff line
		@@ -87,8 +87,10 @@ bool fs_mgr_vendor_overlay_mount(const std::string& overlay_top, const std::stri
		return false;
		}

		auto options =
		"override_creds=off,"s + kLowerdirOption + source_directory + ":" + vendor_mount_point;
		auto options = kLowerdirOption + source_directory + ":" + vendor_mount_point;
		if (fs_mgr_overlayfs_valid() == OverlayfsValidResult::kOverrideCredsRequired) {
		options += ",override_creds=off";
		}
		auto report = "__mount(source=overlay,target="s + vendor_mount_point + ",type=overlay," +
		options + ")=";
		auto ret = mount("overlay", vendor_mount_point.c_str(), "overlay", MS_RDONLY \| MS_RELATIME,
		@@ -117,7 +119,7 @@ bool fs_mgr_vendor_overlay_mount_all() {
		}
		const auto vendor_overlay_dirs = fs_mgr_get_vendor_overlay_dirs(overlay_top);
		if (vendor_overlay_dirs.empty()) return true;
		if (!fs_mgr_overlayfs_supports_override_creds()) {
		if (fs_mgr_overlayfs_valid() == OverlayfsValidResult::kNotSupported) {
		LINFO << "vendor overlay: kernel does not support overlayfs";
		return false;
		}

fs_mgr/include/fs_mgr_overlayfs.h

+7 −1

Original line number	Diff line number	Diff line
		@@ -31,4 +31,10 @@ bool fs_mgr_overlayfs_setup(const char* backing = nullptr, const char* mount_poi
		bool fs_mgr_overlayfs_teardown(const char* mount_point = nullptr, bool* change = nullptr);
		bool fs_mgr_has_shared_blocks(const std::string& mount_point, const std::string& dev);
		std::string fs_mgr_get_context(const std::string& mount_point);
		bool fs_mgr_overlayfs_supports_override_creds();

		enum class OverlayfsValidResult {
		kNotSupported = 0,
		kOk,
		kOverrideCredsRequired,
		};
		OverlayfsValidResult fs_mgr_overlayfs_valid();