Merge "Revert "Use Apex sepolicy if it's available""
diff --git a/init/Android.bp b/init/Android.bp
index c39d163..66427dc 100644
--- a/init/Android.bp
+++ b/init/Android.bp
@@ -162,15 +162,12 @@
"libavb",
"libc++fs",
"libcgrouprc_format",
- "libfsverity_init",
"liblmkd_utils",
- "libmini_keyctl_static",
"libmodprobe",
"libprocinfo",
"libprotobuf-cpp-lite",
"libpropertyinfoserializer",
"libpropertyinfoparser",
- "libsigningutils",
"libsnapshot_cow",
"libsnapshot_init",
"libxml2",
@@ -181,7 +178,6 @@
"libbacktrace",
"libbase",
"libbootloader_message",
- "libcrypto",
"libcutils",
"libdl",
"libext4_utils",
@@ -196,7 +192,6 @@
"libprocessgroup_setup",
"libselinux",
"libutils",
- "libziparchive",
],
bootstrap: true,
visibility: [":__subpackages__"],
diff --git a/init/first_stage_init.cpp b/init/first_stage_init.cpp
index 3cd0252..c7b7b0c 100644
--- a/init/first_stage_init.cpp
+++ b/init/first_stage_init.cpp
@@ -254,9 +254,6 @@
// stage init
CHECKCALL(mount("tmpfs", kSecondStageRes, "tmpfs", MS_NOEXEC | MS_NOSUID | MS_NODEV,
"mode=0755,uid=0,gid=0"))
-
- // First stage init stores Mainline sepolicy here.
- CHECKCALL(mkdir("/dev/selinux", 0744));
#undef CHECKCALL
SetStdioToDevNull(argv);
diff --git a/init/property_service.cpp b/init/property_service.cpp
index bdd5677..70e26ec 100644
--- a/init/property_service.cpp
+++ b/init/property_service.cpp
@@ -1171,9 +1171,6 @@
// Don't check for failure here, since we don't always have all of these partitions.
// E.g. In case of recovery, the vendor partition will not have mounted and we
// still need the system / platform properties to function.
- if (access("/dev/selinux/apex_property_contexts", R_OK) != -1) {
- LoadPropertyInfoFromFile("/dev/selinux/apex_property_contexts", &property_infos);
- }
if (access("/system_ext/etc/selinux/system_ext_property_contexts", R_OK) != -1) {
LoadPropertyInfoFromFile("/system_ext/etc/selinux/system_ext_property_contexts",
&property_infos);
@@ -1197,7 +1194,6 @@
LoadPropertyInfoFromFile("/vendor_property_contexts", &property_infos);
LoadPropertyInfoFromFile("/product_property_contexts", &property_infos);
LoadPropertyInfoFromFile("/odm_property_contexts", &property_infos);
- LoadPropertyInfoFromFile("/dev/selinux/apex_property_contexts", &property_infos);
}
auto serialized_contexts = std::string();
diff --git a/init/selinux.cpp b/init/selinux.cpp
index c89c5ab..28cd012 100644
--- a/init/selinux.cpp
+++ b/init/selinux.cpp
@@ -26,29 +26,26 @@
// The monolithic policy variant is for legacy non-treble devices that contain a single SEPolicy
// file located at /sepolicy and is directly loaded into the kernel SELinux subsystem.
-// The split policy is for supporting treble devices and updateable apexes. It splits the SEPolicy
-// across files on /system/etc/selinux (the 'plat' portion of the policy), /vendor/etc/selinux
-// (the 'vendor' portion of the policy), /system_ext/etc/selinux, /product/etc/selinux,
-// /odm/etc/selinux, and /dev/selinux (the apex portion of policy). This is necessary to allow
-// images to be updated independently of the vendor image, while maintaining contributions from
-// multiple partitions in the SEPolicy. This is especially important for VTS testing, where the
-// SEPolicy on the Google System Image may not be identical to the system image shipped on a
-// vendor's device.
+// The split policy is for supporting treble devices. It splits the SEPolicy across files on
+// /system/etc/selinux (the 'plat' portion of the policy) and /vendor/etc/selinux (the 'vendor'
+// portion of the policy). This is necessary to allow the system image to be updated independently
+// of the vendor image, while maintaining contributions from both partitions in the SEPolicy. This
+// is especially important for VTS testing, where the SEPolicy on the Google System Image may not be
+// identical to the system image shipped on a vendor's device.
// The split SEPolicy is loaded as described below:
// 1) There is a precompiled SEPolicy located at either /vendor/etc/selinux/precompiled_sepolicy or
// /odm/etc/selinux/precompiled_sepolicy if odm parition is present. Stored along with this file
-// are the sha256 hashes of the parts of the SEPolicy on /system, /system_ext, /product, and apex
-// that were used to compile this precompiled policy. The system partition contains a similar
-// sha256 of the parts of the SEPolicy that it currently contains. Symmetrically, system_ext,
-// product, and apex contain sha256 hashes of their SEPolicy. Init loads this
+// are the sha256 hashes of the parts of the SEPolicy on /system, /system_ext and /product that
+// were used to compile this precompiled policy. The system partition contains a similar sha256
+// of the parts of the SEPolicy that it currently contains. Symmetrically, system_ext and
+// product paritition contain sha256 hashes of their SEPolicy. The init loads this
// precompiled_sepolicy directly if and only if the hashes along with the precompiled SEPolicy on
-// /vendor or /odm match the hashes for system, system_ext, product, and apex SEPolicy,
-// respectively.
-// 2) If these hashes do not match, then either /system or /system_ext /product, or apex (or some of
-// them) have been updated out of sync with /vendor (or /odm if it is present) and the init needs
-// to compile the SEPolicy. /system contains the SEPolicy compiler, secilc, and it is used by
-// the OpenSplitPolicy() function below to compile the SEPolicy to a temp directory and load it.
+// /vendor or /odm match the hashes for system, system_ext and product SEPolicy, respectively.
+// 2) If these hashes do not match, then either /system or /system_ext or /product (or some of them)
+// have been updated out of sync with /vendor (or /odm if it is present) and the init needs to
+// compile the SEPolicy. /system contains the SEPolicy compiler, secilc, and it is used by the
+// OpenSplitPolicy() function below to compile the SEPolicy to a temp directory and load it.
// That function contains even more documentation with the specific implementation details of how
// the SEPolicy is compiled if needed.
@@ -61,25 +58,19 @@
#include <stdlib.h>
#include <sys/wait.h>
#include <unistd.h>
-#include <fstream>
-#include <CertUtils.h>
#include <android-base/chrono_utils.h>
#include <android-base/file.h>
#include <android-base/logging.h>
#include <android-base/parseint.h>
#include <android-base/result.h>
-#include <android-base/scopeguard.h>
#include <android-base/strings.h>
#include <android-base/unique_fd.h>
#include <fs_avb/fs_avb.h>
#include <fs_mgr.h>
-#include <fsverity_init.h>
#include <libgsi/libgsi.h>
#include <libsnapshot/snapshot.h>
-#include <mini_keyctl_utils.h>
#include <selinux/android.h>
-#include <ziparchive/zip_archive.h>
#include "block_dev_initializer.h"
#include "debug_ramdisk.h"
@@ -256,7 +247,6 @@
precompiled_sepolicy + ".system_ext_sepolicy_and_mapping.sha256"},
{"/product/etc/selinux/product_sepolicy_and_mapping.sha256",
precompiled_sepolicy + ".product_sepolicy_and_mapping.sha256"},
- {"/dev/selinux/apex_sepolicy.sha256", precompiled_sepolicy + ".apex_sepolicy.sha256"},
};
for (const auto& [actual_id_path, precompiled_id_path] : sepolicy_hashes) {
@@ -335,7 +325,7 @@
// * vendor -- policy needed due to logic contained in the vendor image,
// * mapping -- mapping policy which helps preserve forward-compatibility of non-platform policy
// with newer versions of platform policy.
- // * (optional) policy needed due to logic on product, system_ext, odm, or apex.
+ // * (optional) policy needed due to logic on product, system_ext, or odm images.
// secilc is invoked to compile the above three policy files into a single monolithic policy
// file. This file is then loaded into the kernel.
@@ -431,12 +421,6 @@
if (access(odm_policy_cil_file.c_str(), F_OK) == -1) {
odm_policy_cil_file.clear();
}
-
- // apex_sepolicy.cil is default but optional.
- std::string apex_policy_cil_file("/dev/selinux/apex_sepolicy.cil");
- if (access(apex_policy_cil_file.c_str(), F_OK) == -1) {
- apex_policy_cil_file.clear();
- }
const std::string version_as_string = std::to_string(SEPOLICY_VERSION);
// clang-format off
@@ -479,9 +463,6 @@
if (!odm_policy_cil_file.empty()) {
compile_args.push_back(odm_policy_cil_file.c_str());
}
- if (!apex_policy_cil_file.empty()) {
- compile_args.push_back(apex_policy_cil_file.c_str());
- }
compile_args.push_back(nullptr);
if (!ForkExecveAndWaitForCompletion(compile_args[0], (char**)compile_args.data())) {
@@ -508,197 +489,6 @@
return true;
}
-constexpr const char* kSigningCertRelease =
- "/system/etc/selinux/com.android.sepolicy.cert-release.der";
-constexpr const char* kFsVerityProcPath = "/proc/sys/fs/verity";
-const std::string kSepolicyApexMetadataDir = "/metadata/sepolicy/";
-const std::string kSepolicyApexSystemDir = "/system/etc/selinux/apex/";
-const std::string kSepolicyZip = "SEPolicy.zip";
-const std::string kSepolicySignature = "SEPolicy.zip.sig";
-
-const std::string kTmpfsDir = "/dev/selinux/";
-
-// Files that are deleted after policy is compiled/loaded.
-const std::vector<std::string> kApexSepolicyTmp{"apex_sepolicy.cil", "apex_sepolicy.sha256"};
-// Files that need to persist because they are used by userspace processes.
-const std::vector<std::string> kApexSepolicy{"apex_file_contexts", "apex_property_contexts",
- "apex_service_contexts", "apex_seapp_contexts",
- "apex_test"};
-
-Result<void> PutFileInTmpfs(ZipArchiveHandle archive, const std::string& fileName) {
- ZipEntry entry;
- std::string dstPath = kTmpfsDir + fileName;
-
- int ret = FindEntry(archive, fileName, &entry);
- if (ret != 0) {
- // All files are optional. If a file doesn't exist, return without error.
- return {};
- }
-
- unique_fd fd(TEMP_FAILURE_RETRY(
- open(dstPath.c_str(), O_WRONLY | O_CREAT | O_TRUNC | O_CLOEXEC, S_IRUSR | S_IWUSR)));
- if (fd == -1) {
- return Error() << "Failed to open " << dstPath;
- }
-
- ret = ExtractEntryToFile(archive, &entry, fd);
- if (ret != 0) {
- return Error() << "Failed to extract entry \"" << fileName << "\" ("
- << entry.uncompressed_length << " bytes) to \"" << dstPath
- << "\": " << ErrorCodeString(ret);
- }
-
- return {};
-}
-
-Result<void> GetPolicyFromApex(const std::string& dir) {
- LOG(INFO) << "Loading APEX Sepolicy from " << dir + kSepolicyZip;
- unique_fd fd(open((dir + kSepolicyZip).c_str(), O_RDONLY | O_BINARY | O_CLOEXEC));
- if (fd < 0) {
- return ErrnoError() << "Failed to open package " << dir + kSepolicyZip;
- }
-
- ZipArchiveHandle handle;
- int ret = OpenArchiveFd(fd.get(), (dir + kSepolicyZip).c_str(), &handle,
- /*assume_ownership=*/false);
- if (ret < 0) {
- return Error() << "Failed to open package " << dir + kSepolicyZip << ": "
- << ErrorCodeString(ret);
- }
-
- auto handle_guard = android::base::make_scope_guard([&handle] { CloseArchive(handle); });
-
- for (const auto& file : kApexSepolicy) {
- auto extract = PutFileInTmpfs(handle, file);
- if (!extract.ok()) {
- return extract.error();
- }
- }
- for (const auto& file : kApexSepolicyTmp) {
- auto extract = PutFileInTmpfs(handle, file);
- if (!extract.ok()) {
- return extract.error();
- }
- }
- return {};
-}
-
-Result<void> LoadSepolicyApexCerts() {
- key_serial_t keyring_id = android::GetKeyringId(".fs-verity");
- if (keyring_id < 0) {
- return Error() << "Failed to find .fs-verity keyring id";
- }
-
- // TODO(b/199914227) the release key should always exist. Once it's checked in, start
- // throwing an error here if it doesn't exist.
- if (access(kSigningCertRelease, F_OK) == 0) {
- LoadKeyFromFile(keyring_id, "fsv_sepolicy_apex_release", kSigningCertRelease);
- }
- return {};
-}
-
-Result<void> SepolicyFsVerityCheck() {
- return Error() << "TODO implementent support for fsverity SEPolicy.";
-}
-
-Result<void> SepolicyCheckSignature(const std::string& dir) {
- std::string signature;
- if (!android::base::ReadFileToString(dir + kSepolicySignature, &signature)) {
- return ErrnoError() << "Failed to read " << kSepolicySignature;
- }
-
- std::fstream sepolicyZip(dir + kSepolicyZip, std::ios::in | std::ios::binary);
- if (!sepolicyZip) {
- return Error() << "Failed to open " << kSepolicyZip;
- }
- sepolicyZip.seekg(0);
- std::string sepolicyStr((std::istreambuf_iterator<char>(sepolicyZip)),
- std::istreambuf_iterator<char>());
-
- auto releaseKey = extractPublicKeyFromX509(kSigningCertRelease);
- if (!releaseKey.ok()) {
- return releaseKey.error();
- }
-
- return verifySignature(sepolicyStr, signature, *releaseKey);
-}
-
-Result<void> SepolicyVerify(const std::string& dir, bool supportsFsVerity) {
- if (supportsFsVerity) {
- auto fsVerityCheck = SepolicyFsVerityCheck();
- if (fsVerityCheck.ok()) {
- return fsVerityCheck;
- }
- // TODO(b/199914227) If the device supports fsverity, but we fail here, we should fail to
- // boot and not carry on. For now, fallback to a signature checkuntil the fsverity
- // logic is implemented.
- LOG(INFO) << "Falling back to standard signature check. " << fsVerityCheck.error();
- }
-
- auto sepolicySignature = SepolicyCheckSignature(dir);
- if (!sepolicySignature.ok()) {
- return Error() << "Apex SEPolicy failed signature check";
- }
- return {};
-}
-
-void CleanupApexSepolicy() {
- for (const auto& file : kApexSepolicyTmp) {
- std::string path = kTmpfsDir + file;
- unlink(path.c_str());
- }
-}
-
-// Updatable sepolicy is shipped within an zip within an APEX. Because
-// it needs to be available before Apexes are mounted, apexd copies
-// the zip from the APEX and stores it in /metadata/sepolicy. If there is
-// no updatable sepolicy in /metadata/sepolicy, then the updatable policy is
-// loaded from /system/etc/selinux/apex. Init performs the following
-// steps on boot:
-//
-// 1. Validates the zip by checking its signature against a public key that is
-// stored in /system/etc/selinux.
-// 2. Extracts files from zip and stores them in /dev/selinux.
-// 3. Checks if the apex_sepolicy.sha256 matches the sha256 of precompiled_sepolicy.
-// if so, the precompiled sepolicy is used. Otherwise, an on-device compile of the policy
-// is used. This is the same flow as on-device compilation of policy for Treble.
-// 4. Cleans up files in /dev/selinux which are no longer needed.
-// 5. Restorecons the remaining files in /dev/selinux.
-// 6. Sets selinux into enforcing mode and continues normal booting.
-//
-void PrepareApexSepolicy() {
- bool supportsFsVerity = access(kFsVerityProcPath, F_OK) == 0;
- if (supportsFsVerity) {
- auto loadSepolicyApexCerts = LoadSepolicyApexCerts();
- if (!loadSepolicyApexCerts.ok()) {
- // TODO(b/199914227) If the device supports fsverity, but we fail here, we should fail
- // to boot and not carry on. For now, fallback to a signature checkuntil the fsverity
- // logic is implemented.
- LOG(INFO) << loadSepolicyApexCerts.error();
- }
- }
- // If apex sepolicy zip exists in /metadata/sepolicy, use that, otherwise use version on
- // /system.
- auto dir = (access((kSepolicyApexMetadataDir + kSepolicyZip).c_str(), F_OK) == 0)
- ? kSepolicyApexMetadataDir
- : kSepolicyApexSystemDir;
-
- auto sepolicyVerify = SepolicyVerify(dir, supportsFsVerity);
- if (!sepolicyVerify.ok()) {
- LOG(INFO) << "Error: " << sepolicyVerify.error();
- // If signature verification fails, fall back to version on /system.
- // This file doesn't need to be verified because it lives on the system partition which
- // is signed and protected by verified boot.
- dir = kSepolicyApexSystemDir;
- }
-
- auto apex = GetPolicyFromApex(dir);
- if (!apex.ok()) {
- // TODO(b/199914227) Make failure fatal. For now continue booting with non-apex sepolicy.
- LOG(ERROR) << apex.error();
- }
-}
-
void ReadPolicy(std::string* policy) {
PolicyFile policy_file;
@@ -950,12 +740,9 @@
LOG(INFO) << "Opening SELinux policy";
- PrepareApexSepolicy();
-
// Read the policy before potentially killing snapuserd.
std::string policy;
ReadPolicy(&policy);
- CleanupApexSepolicy();
auto snapuserd_helper = SnapuserdSelinuxHelper::CreateIfNeeded();
if (snapuserd_helper) {
@@ -973,13 +760,6 @@
snapuserd_helper = nullptr;
}
- // This restorecon is intentionally done before SelinuxSetEnforcement because the permissions
- // needed to transition files from tmpfs to *_contexts_file context should not be granted to
- // any process after selinux is set into enforcing mode.
- if (selinux_android_restorecon("/dev/selinux/", SELINUX_ANDROID_RESTORECON_RECURSE) == -1) {
- PLOG(FATAL) << "restorecon failed of /dev/selinux failed";
- }
-
SelinuxSetEnforcement();
// We're in the kernel domain and want to transition to the init domain. File systems that