Merge "fs_mgr: Refactor mandatory overlayfs kernel patch checks" into main (bb1cc95f) · Commits · e / os / android_system_core

fs_mgr/fs_mgr.cpp

+23 −22

Original line number	Diff line number	Diff line
		@@ -2227,8 +2227,8 @@ bool fs_mgr_create_canonical_mount_point(const std::string& mount_point) {
		}

		bool fs_mgr_mount_overlayfs_fstab_entry(const FstabEntry& entry) {
		auto overlayfs_valid_result = fs_mgr_overlayfs_valid();
		if (overlayfs_valid_result == OverlayfsValidResult::kNotSupported) {
		const auto overlayfs_check_result = android::fs_mgr::CheckOverlayfs();
		if (!overlayfs_check_result.supported) {
		LERROR << __FUNCTION__ << "(): kernel does not support overlayfs";
		return false;
		}
		@@ -2280,10 +2280,7 @@ bool fs_mgr_mount_overlayfs_fstab_entry(const FstabEntry& entry) {
		}
		}

		auto options = "lowerdir=" + lowerdir;
		if (overlayfs_valid_result == OverlayfsValidResult::kOverrideCredsRequired) {
		options += ",override_creds=off";
		}
		const auto options = "lowerdir=" + lowerdir + overlayfs_check_result.mount_flags;

		// Use "overlay-" + entry.blk_device as the mount() source, so that adb-remout-test don't
		// confuse this with adb remount overlay, whose device name is "overlay".
		@@ -2339,30 +2336,34 @@ std::string fs_mgr_get_context(const std::string& mount_point) {
		return context;
		}

		OverlayfsValidResult fs_mgr_overlayfs_valid() {
		// Overlayfs available in the kernel, and patched for override_creds?
		if (access("/sys/module/overlay/parameters/override_creds", F_OK) == 0) {
		return OverlayfsValidResult::kOverrideCredsRequired;
		}
		namespace android {
		namespace fs_mgr {

		OverlayfsCheckResult CheckOverlayfs() {
		if (!fs_mgr_filesystem_available("overlay")) {
		return OverlayfsValidResult::kNotSupported;
		return {.supported = false};
		}
		struct utsname uts;
		if (uname(&uts) == -1) {
		return OverlayfsValidResult::kNotSupported;
		return {.supported = false};
		}
		int major, minor;
		if (sscanf(uts.release, "%d.%d", &major, &minor) != 2) {
		return OverlayfsValidResult::kNotSupported;
		return {.supported = false};
		}
		if (major < 4) {
		return OverlayfsValidResult::kOk;
		// Overlayfs available in the kernel, and patched for override_creds?
		if (access("/sys/module/overlay/parameters/override_creds", F_OK) == 0) {
		auto mount_flags = ",override_creds=off"s;
		if (major > 5 \|\| (major == 5 && minor >= 15)) {
		mount_flags += ",userxattr"s;
		}
		if (major > 4) {
		return OverlayfsValidResult::kNotSupported;
		return {.supported = true, .mount_flags = mount_flags};
		}
		if (minor > 3) {
		return OverlayfsValidResult::kNotSupported;
		if (major < 4 \|\| (major == 4 && minor <= 3)) {
		return {.supported = true};
		}
		return OverlayfsValidResult::kOk;
		return {.supported = false};
		}

		} // namespace fs_mgr
		} // namespace android

fs_mgr/fs_mgr_overlayfs_mount.cpp

+2 −20

Original line number	Diff line number	Diff line
		@@ -23,7 +23,6 @@
		#include <sys/stat.h>
		#include <sys/statvfs.h>
		#include <sys/types.h>
		#include <sys/utsname.h>
		#include <sys/vfs.h>
		#include <unistd.h>

		@@ -218,17 +217,6 @@ static std::string fs_mgr_get_overlayfs_candidate(const std::string& mount_point
		return "";
		}

		static inline bool KernelSupportsUserXattrs() {
		struct utsname uts;
		uname(&uts);

		int major, minor;
		if (sscanf(uts.release, "%d.%d", &major, &minor) != 2) {
		return false;
		}
		return major > 5 \|\| (major == 5 && minor >= 15);
		}

		const std::string fs_mgr_mount_point(const std::string& mount_point) {
		if ("/"s != mount_point) return mount_point;
		return "/system";
		@@ -240,13 +228,7 @@ static std::string fs_mgr_get_overlayfs_options(const FstabEntry& entry) {
		auto candidate = fs_mgr_get_overlayfs_candidate(mount_point);
		if (candidate.empty()) return "";
		auto ret = kLowerdirOption + mount_point + "," + kUpperdirOption + candidate + kUpperName +
		",workdir=" + candidate + kWorkName;
		if (fs_mgr_overlayfs_valid() == OverlayfsValidResult::kOverrideCredsRequired) {
		ret += ",override_creds=off";
		}
		if (KernelSupportsUserXattrs()) {
		ret += ",userxattr";
		}
		",workdir=" + candidate + kWorkName + android::fs_mgr::CheckOverlayfs().mount_flags;
		for (const auto& flag : android::base::Split(entry.fs_options, ",")) {
		if (android::base::StartsWith(flag, "context=")) {
		ret += "," + flag;
		@@ -608,7 +590,7 @@ bool OverlayfsSetupAllowed(bool verbose) {
		return false;
		}
		// Check mandatory kernel patches.
		if (fs_mgr_overlayfs_valid() == OverlayfsValidResult::kNotSupported) {
		if (!android::fs_mgr::CheckOverlayfs().supported) {
		if (verbose) {
		LOG(ERROR) << "Kernel does not support overlayfs";
		}

fs_mgr/fs_mgr_priv.h

+7 −7

Original line number	Diff line number	Diff line
		@@ -100,18 +100,18 @@ bool fs_mgr_is_f2fs(const std::string& blk_device);
		bool fs_mgr_filesystem_available(const std::string& filesystem);
		std::string fs_mgr_get_context(const std::string& mount_point);

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

		namespace android {
		namespace fs_mgr {

		bool UnmapDevice(const std::string& name);
		bool InRecovery();

		struct OverlayfsCheckResult {
		bool supported;
		std::string mount_flags;
		};

		OverlayfsCheckResult CheckOverlayfs();

		} // namespace fs_mgr
		} // namespace android

fs_mgr/fs_mgr_vendor_overlay.cpp

+3 −5

Original line number	Diff line number	Diff line
		@@ -85,10 +85,8 @@ bool fs_mgr_vendor_overlay_mount(const std::pair<std::string, std::string>& moun
		return false;
		}

		auto options = kLowerdirOption + source_directory + ":" + vendor_mount_point;
		if (fs_mgr_overlayfs_valid() == OverlayfsValidResult::kOverrideCredsRequired) {
		options += ",override_creds=off";
		}
		const auto options = kLowerdirOption + source_directory + ":" + vendor_mount_point +
		android::fs_mgr::CheckOverlayfs().mount_flags;
		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_NOATIME,
		@@ -120,7 +118,7 @@ bool fs_mgr_vendor_overlay_mount_all() {

		const auto vendor_overlay_dirs = fs_mgr_get_vendor_overlay_dirs(vndk_version);
		if (vendor_overlay_dirs.empty()) return true;
		if (fs_mgr_overlayfs_valid() == OverlayfsValidResult::kNotSupported) {
		if (!android::fs_mgr::CheckOverlayfs().supported) {
		LINFO << "vendor overlay: kernel does not support overlayfs";
		return false;
		}