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Merge "fs_mgr: overlayfs deal with verity detection issues"

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This commit is contained in:
Treehugger Robot 2018-10-10 16:51:57 +00:00 • committed by Gerrit Code Review
commit 042f2da1f3
1 changed files with 42 additions and 16 deletions
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58
fs_mgr/fs_mgr_overlayfs.cpp
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@ -29,6 +29,7 @@
#include <sys/vfs.h>
#include <unistd.h>
#include <algorithm>
#include <map>
#include <memory>
#include <string>
@ -42,10 +43,12 @@
#include <ext4_utils/ext4_utils.h>
#include <fs_mgr_overlayfs.h>
#include <fstab/fstab.h>
#include <libdm/dm.h>
#include "fs_mgr_priv.h"
using namespace std::literals;
using namespace android::dm;
#if ALLOW_ADBD_DISABLE_VERITY == 0 // If we are a user build, provide stubs
@ -222,13 +225,12 @@ bool fs_mgr_overlayfs_already_mounted(const std::string& mount_point) {
return false;
}
bool fs_mgr_overlayfs_verity_enabled(const std::string& basename_mount_point) {
auto found = false;
fs_mgr_update_verity_state(
[&basename_mount_point, &found](fstab_rec*, const char* mount_point, int, int) {
if (mount_point && (basename_mount_point == mount_point)) found = true;
});
return found;
std::vector<std::string> fs_mgr_overlayfs_verity_enabled_list() {
std::vector<std::string> ret;
fs_mgr_update_verity_state([&ret](fstab_rec*, const char* mount_point, int, int) {
ret.emplace_back(mount_point);
});
return ret;
}
bool fs_mgr_wants_overlayfs(const fstab_rec* fsrec) {
@ -254,7 +256,7 @@ bool fs_mgr_wants_overlayfs(const fstab_rec* fsrec) {
if (!fs_mgr_overlayfs_enabled(fsrec)) return false;
return !fs_mgr_overlayfs_verity_enabled(android::base::Basename(fsrec_mount_point));
return true;
}
bool fs_mgr_rm_all(const std::string& path, bool* change = nullptr) {
@ -445,11 +447,16 @@ std::vector<std::string> fs_mgr_candidate_list(const fstab* fstab,
std::vector<std::string> mounts;
if (!fstab) return mounts;
auto verity = fs_mgr_overlayfs_verity_enabled_list();
for (auto i = 0; i < fstab->num_entries; i++) {
const auto fsrec = &fstab->recs[i];
if (!fs_mgr_wants_overlayfs(fsrec)) continue;
std::string new_mount_point(fs_mgr_mount_point(fstab, fsrec->mount_point));
if (mount_point && (new_mount_point != mount_point)) continue;
if (std::find(verity.begin(), verity.end(), android::base::Basename(new_mount_point)) !=
verity.end()) {
continue;
}
auto duplicate_or_more_specific = false;
for (auto it = mounts.begin(); it != mounts.end();) {
if ((*it == new_mount_point) ||
@ -465,16 +472,35 @@ std::vector<std::string> fs_mgr_candidate_list(const fstab* fstab,
}
if (!duplicate_or_more_specific) mounts.emplace_back(new_mount_point);
}
// if not itemized /system or /, system as root, fake up
// fs_mgr_wants_overlayfs evaluation of /system as candidate.
if ((std::find(mounts.begin(), mounts.end(), "/system") == mounts.end()) &&
!fs_mgr_get_entry_for_mount_point(const_cast<struct fstab*>(fstab), "/") &&
!fs_mgr_get_entry_for_mount_point(const_cast<struct fstab*>(fstab), "/system") &&
(!mount_point || ("/system"s == mount_point)) &&
!fs_mgr_overlayfs_verity_enabled("system")) {
mounts.emplace_back("/system");
// if not itemized /system or /, system as root, fake one up?
// do we want or need to?
if (mount_point && ("/system"s != mount_point)) return mounts;
if (std::find(mounts.begin(), mounts.end(), "/system") != mounts.end()) return mounts;
// fs_mgr_overlayfs_verity_enabled_list says not to?
if (std::find(verity.begin(), verity.end(), "system") != verity.end()) return mounts;
// confirm that fstab is missing system
if (fs_mgr_get_entry_for_mount_point(const_cast<struct fstab*>(fstab), "/")) {
return mounts;
}
if (fs_mgr_get_entry_for_mount_point(const_cast<struct fstab*>(fstab), "/system")) {
return mounts;
}
// Manually check dm state because stunted fstab (w/o system as root) borken
auto& dm = DeviceMapper::Instance();
auto found = false;
for (auto& system : {"system", "vroot"}) {
if (dm.GetState(system) == DmDeviceState::INVALID) continue;
std::vector<DeviceMapper::TargetInfo> table;
found = !dm.GetTableStatus(system, &table) || table.empty() || table[0].data.empty() ||
(table[0].data[0] == 'C') || (table[0].data[0] == 'V');
if (found) break;
}
if (!found) mounts.emplace_back("/system");
return mounts;
}