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Merge "Make fs_mgr_overlayfs_mount_fstab_entry() available for user builds" am: 869ab86944 am: c88ce98631

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Original change: https://android-review.googlesource.com/c/platform/system/core/+/1711246

Change-Id: Ie9f509f32dfc85deaa38480b7a51c7206ea5aa7e
This commit is contained in:
Yo Chiang 2021-05-27 09:38:41 +00:00 • committed by Automerger Merge Worker
commit 30687fbdbe
5 changed files with 75 additions and 34 deletions
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69
fs_mgr/fs_mgr.cpp
View file

@ -2265,3 +2265,72 @@ std::string fs_mgr_get_super_partition_name(int slot) {
}
return LP_METADATA_DEFAULT_PARTITION_NAME;
}
bool fs_mgr_mount_overlayfs_fstab_entry(const FstabEntry& entry) {
auto overlayfs_valid_result = fs_mgr_overlayfs_valid();
if (overlayfs_valid_result == OverlayfsValidResult::kNotSupported) {
LERROR << __FUNCTION__ << "(): kernel does not support overlayfs";
return false;
}
#if ALLOW_ADBD_DISABLE_VERITY == 0
// Allowlist the mount point if user build.
static const std::vector<const std::string> kAllowedPaths = {
"/odm", "/odm_dlkm", "/oem", "/product", "/system_ext", "/vendor", "/vendor_dlkm",
};
static const std::vector<const std::string> kAllowedPrefixes = {
"/mnt/product/",
"/mnt/vendor/",
};
if (std::none_of(kAllowedPaths.begin(), kAllowedPaths.end(),
[&entry](const auto& path) -> bool {
return entry.mount_point == path ||
StartsWith(entry.mount_point, path + "/");
}) &&
std::none_of(kAllowedPrefixes.begin(), kAllowedPrefixes.end(),
[&entry](const auto& prefix) -> bool {
return entry.mount_point != prefix &&
StartsWith(entry.mount_point, prefix);
})) {
LERROR << __FUNCTION__
<< "(): mount point is forbidden on user build: " << entry.mount_point;
return false;
}
#endif // ALLOW_ADBD_DISABLE_VERITY == 0
// Create the mount point in case it doesn't exist.
mkdir(entry.mount_point.c_str(), 0755);
// Ensure that mount point exists and doesn't contain symbolic link or /../.
std::string mount_point;
if (!Realpath(entry.mount_point, &mount_point)) {
PERROR << __FUNCTION__ << "(): failed to realpath " << entry.mount_point;
return false;
}
if (entry.mount_point != mount_point) {
LERROR << __FUNCTION__ << "(): mount point must be a canonicalized path: realpath "
<< entry.mount_point << " = " << mount_point;
return false;
}
auto options = "lowerdir=" + entry.lowerdir;
if (overlayfs_valid_result == OverlayfsValidResult::kOverrideCredsRequired) {
options += ",override_creds=off";
}
// 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".
// Overlayfs is a pseudo filesystem, so the source device is a symbolic value and isn't used to
// back the filesystem. However the device name would be shown in /proc/mounts.
auto source = "overlay-" + entry.blk_device;
auto report = "__mount(source=" + source + ",target=" + entry.mount_point + ",type=overlay," +
options + ")=";
auto ret = mount(source.c_str(), entry.mount_point.c_str(), "overlay", MS_RDONLY | MS_NOATIME,
options.c_str());
if (ret) {
PERROR << report << ret;
return false;
}
LINFO << report << ret;
return true;
}

32
fs_mgr/fs_mgr_overlayfs.cpp
View file

@ -92,10 +92,6 @@ bool fs_mgr_overlayfs_mount_all(Fstab*) {
return false;
}
bool fs_mgr_overlayfs_mount_fstab_entry(const android::fs_mgr::FstabEntry&) {
return false;
}
std::vector<std::string> fs_mgr_overlayfs_required_devices(Fstab*) {
return {};
}
@ -1299,34 +1295,6 @@ static void TryMountScratch() {
}
}
bool fs_mgr_overlayfs_mount_fstab_entry(const android::fs_mgr::FstabEntry& entry) {
if (fs_mgr_overlayfs_invalid()) return false;
// Create the mount point in case it doesn't exist.
mkdir(entry.mount_point.c_str(), 0755);
auto options = kLowerdirOption + entry.lowerdir;
if (fs_mgr_overlayfs_valid() == OverlayfsValidResult::kOverrideCredsRequired) {
options += ",override_creds=off";
}
// 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".
// Overlayfs is a pseudo filesystem, so the source device is a symbolic value and isn't used to
// back the filesystem. However the device name would be shown in /proc/mounts.
auto source = "overlay-" + entry.blk_device;
auto report = "__mount(source=" + source + ",target=" + entry.mount_point + ",type=overlay," +
options + ")=";
auto ret = mount(source.c_str(), entry.mount_point.c_str(), "overlay", MS_RDONLY | MS_NOATIME,
options.c_str());
if (ret) {
PERROR << report << ret;
return false;
}
LINFO << report << ret;
return true;
}
bool fs_mgr_overlayfs_mount_all(Fstab* fstab) {
auto ret = false;
if (fs_mgr_overlayfs_invalid()) return ret;

5
fs_mgr/include/fs_mgr.h
View file

@ -131,3 +131,8 @@ int fs_mgr_remount_userdata_into_checkpointing(android::fs_mgr::Fstab* fstab);
// Finds the dm_bow device on which this block device is stacked, or returns
// empty string
std::string fs_mgr_find_bow_device(const std::string& block_device);
// Like fs_mgr_do_mount_one() but for overlayfs fstab entries.
// Unlike fs_mgr_overlayfs, mount overlayfs without upperdir and workdir, so the
// filesystem cannot be remount read-write.
bool fs_mgr_mount_overlayfs_fstab_entry(const android::fs_mgr::FstabEntry& entry);

1
fs_mgr/include/fs_mgr_overlayfs.h
View file

@ -27,7 +27,6 @@
android::fs_mgr::Fstab fs_mgr_overlayfs_candidate_list(const android::fs_mgr::Fstab& fstab);
bool fs_mgr_overlayfs_mount_all(android::fs_mgr::Fstab* fstab);
bool fs_mgr_overlayfs_mount_fstab_entry(const android::fs_mgr::FstabEntry& entry);
std::vector<std::string> fs_mgr_overlayfs_required_devices(android::fs_mgr::Fstab* fstab);
bool fs_mgr_overlayfs_setup(const char* backing = nullptr, const char* mount_point = nullptr,
bool* change = nullptr, bool force = true);

2
init/first_stage_mount.cpp
View file

@ -574,7 +574,7 @@ bool FirstStageMount::MountPartitions() {
for (const auto& entry : fstab_) {
if (entry.fs_type == "overlay") {
fs_mgr_overlayfs_mount_fstab_entry(entry);
fs_mgr_mount_overlayfs_fstab_entry(entry);
}
}