Merge "Securely encrypt the master key"master-soong

9 files changed, 221 insertions, 403 deletions

diff --git a/ext4_utils/Android.mk b/ext4_utils/Android.mk
index 08088863..31a4b711 100644
--- a/ext4_utils/Android.mk
+++ b/ext4_utils/Android.mk
@@ -53,8 +53,8 @@ include $(BUILD_HOST_EXECUTABLE)
 #
 
 libext4_utils_src_files += \
+    key_control.cpp \
     ext4_crypt.cpp \
-    e4crypt_static.c \
     unencrypted_properties.cpp
 
 ifneq ($(HOST_OS),windows)
diff --git a/ext4_utils/e4crypt_static.c b/ext4_utils/e4crypt_static.c
deleted file mode 100644
index 1a62ce4a..00000000
--- a/ext4_utils/e4crypt_static.c
+++ /dev/null
@@ -1,147 +0,0 @@
-/*
- * Copyright (c) 2015 Google, Inc.
- */
-
-#define TAG "ext4_utils"
-
-#include <dirent.h>
-#include <errno.h>
-#include <string.h>
-#include <unistd.h>
-
-#include <sys/xattr.h>
-#include <sys/syscall.h>
-#include <sys/stat.h>
-
-#include <cutils/klog.h>
-
-#include "ext4_crypt.h"
-
-/* keyring keyctl commands */
-#define KEYCTL_SETPERM        5 /* set permissions for a key in a keyring */
-#define KEYCTL_UNLINK         9 /* unlink a key from a keyring */
-#define KEYCTL_SEARCH        10 /* search for a key in a keyring */
-
-#define XATTR_NAME_ENCRYPTION_POLICY "encryption.policy"
-#define EXT4_KEYREF_DELIMITER ((char)'.')
-
-/* Validate that all path items are available and accessible. */
-static int is_path_valid(const char *path)
-{
-    if (access(path, W_OK)) {
-        KLOG_ERROR(TAG, "Can't access %s: %s\n",strerror(errno), path);
-        return 0;
-    }
-
-    return 1;
-}
-
-/* Checks whether the policy provided is valid */
-static int is_keyref_valid(const char *keyref)
-{
-    char *period = 0;
-    size_t key_location_len = 0;
-
-    /* Key ref must have a key and location delimiter character. */
-    period = strchr(keyref, EXT4_KEYREF_DELIMITER);
-    if (!period) {
-        return 0;
-    }
-
-    /* period must be >= keyref. */
-    key_location_len = period - keyref;
-
-    if (strncmp(keyref, "@t", key_location_len) == 0 ||
-        strncmp(keyref, "@p", key_location_len) == 0 ||
-        strncmp(keyref, "@s", key_location_len) == 0 ||
-        strncmp(keyref, "@u", key_location_len) == 0 ||
-        strncmp(keyref, "@g", key_location_len) == 0 ||
-        strncmp(keyref, "@us", key_location_len) == 0)
-        return 1;
-
-    return 0;
-}
-
-static int is_dir_empty(const char *dirname)
-{
-    int n = 0;
-    struct dirent *d;
-    DIR *dir;
-
-    dir = opendir(dirname);
-    while ((d = readdir(dir)) != NULL) {
-        if (strcmp(d->d_name, "lost+found") == 0) {
-            // Skip lost+found directory
-        } else if (++n > 2) {
-            break;
-        }
-    }
-    closedir(dir);
-    return n <= 2;
-}
-
-int do_policy_set(const char *directory, const char *policy)
-{
-    struct stat st;
-    ssize_t ret;
-
-    if (!is_keyref_valid(policy)) {
-        KLOG_ERROR(TAG, "Policy has invalid format.\n");
-        return -EINVAL;
-    }
-
-    if (!is_path_valid(directory)) {
-        return -EINVAL;
-    }
-
-    stat(directory, &st);
-    if (!S_ISDIR(st.st_mode)) {
-        KLOG_ERROR(TAG, "Can only set policy on a directory (%s)\n", directory);
-        return -EINVAL;
-    }
-
-    if (!is_dir_empty(directory)) {
-        KLOG_ERROR(TAG, "Can only set policy on an empty directory (%s)\n", directory);
-        return -EINVAL;
-    }
-
-    ret = lsetxattr(directory, XATTR_NAME_ENCRYPTION_POLICY, policy,
-                    strlen(policy), 0);
-
-    if (ret) {
-        KLOG_ERROR(TAG, "Failed to set encryption policy for %s: %s\n",
-                   directory, strerror(errno));
-        return -EINVAL;
-    }
-
-    KLOG_INFO(TAG, "Encryption policy for %s is set to %s\n", directory, policy);
-    return 0;
-}
-
-static long keyctl(int cmd, ...)
-{
-    va_list va;
-    unsigned long arg2, arg3, arg4, arg5;
-
-    va_start(va, cmd);
-    arg2 = va_arg(va, unsigned long);
-    arg3 = va_arg(va, unsigned long);
-    arg4 = va_arg(va, unsigned long);
-    arg5 = va_arg(va, unsigned long);
-    va_end(va);
-    return syscall(__NR_keyctl, cmd, arg2, arg3, arg4, arg5);
-}
-
-key_serial_t add_key(const char *type,
-                     const char *description,
-                     const void *payload,
-                     size_t plen,
-                     key_serial_t ringid)
-{
-    return syscall(__NR_add_key, type, description, payload, plen, ringid);
-}
-
-long keyctl_setperm(key_serial_t id, int permissions)
-{
-    return keyctl(KEYCTL_SETPERM, id, permissions);
-}
diff --git a/ext4_utils/ext4_crypt.cpp b/ext4_utils/ext4_crypt.cpp
index bb573323..7d3dc91e 100644
--- a/ext4_utils/ext4_crypt.cpp
+++ b/ext4_utils/ext4_crypt.cpp
@@ -1,120 +1,132 @@
-#define TAG "ext4_utils"
+/*
+ * Copyright (c) 2015 Google, Inc.
+ */
 
-#include "ext4_crypt.h"
+#define TAG "ext4_utils"
 
-#include <string>
-#include <fstream>
-#include <map>
+#include "ext4_crypt_init_extensions.h"
 
+#include <dirent.h>
 #include <errno.h>
-#include <sys/mount.h>
+#include <string.h>
+#include <unistd.h>
+
+#include <sys/xattr.h>
+#include <sys/syscall.h>
+#include <sys/stat.h>
 
 #include <cutils/klog.h>
-#include <cutils/properties.h>
 
 #include "unencrypted_properties.h"
 
-namespace {
-    std::map<std::string, std::string> s_password_store;
-}
-
-bool e4crypt_non_default_key(const char* dir)
-{
-    int type = e4crypt_get_password_type(dir);
+#define XATTR_NAME_ENCRYPTION_POLICY "encryption.policy"
+#define EXT4_KEYREF_DELIMITER ((char)'.')
 
-    // ext4enc:TODO Use consts, not 1 here
-    return type != -1 && type != 1;
-}
+// ext4enc:TODO Include structure from somewhere sensible
+// MUST be in sync with ext4_crypto.c in kernel
+#define EXT4_MAX_KEY_SIZE 76
+struct ext4_encryption_key {
+        uint32_t mode;
+        char raw[EXT4_MAX_KEY_SIZE];
+        uint32_t size;
+};
 
-int e4crypt_get_password_type(const char* path)
+/* Validate that all path items are available and accessible. */
+static int is_path_valid(const char *path)
 {
-    UnencryptedProperties props(path);
-    if (props.Get<std::string>(properties::key).empty()) {
-        KLOG_INFO(TAG, "No master key, so not ext4enc\n");
-        return -1;
+    if (access(path, W_OK)) {
+        KLOG_ERROR(TAG, "Can't access %s: %s\n",strerror(errno), path);
+        return 0;
     }
 
-    return props.Get<int>(properties::type, 1);
+    return 1;
 }
 
-int e4crypt_change_password(const char* path, int crypt_type,
-                            const char* password)
+/* Checks whether the policy provided is valid */
+static int is_keyref_valid(const char *keyref)
 {
-    // ext4enc:TODO Encrypt master key with password securely. Store hash of
-    // master key for validation
-    UnencryptedProperties props(path);
-    if (   props.Set(properties::password, password)
-        && props.Set(properties::type, crypt_type))
-        return 0;
-    return -1;
-}
+    char *period = 0;
+    size_t key_location_len = 0;
 
-int e4crypt_crypto_complete(const char* path)
-{
-    KLOG_INFO(TAG, "ext4 crypto complete called on %s\n", path);
-    if (UnencryptedProperties(path).Get<std::string>(properties::key).empty()) {
-        KLOG_INFO(TAG, "No master key, so not ext4enc\n");
-        return -1;
+    /* Key ref must have a key and location delimiter character. */
+    period = strchr(keyref, EXT4_KEYREF_DELIMITER);
+    if (!period) {
+        return 0;
     }
 
+    /* period must be >= keyref. */
+    key_location_len = period - keyref;
+
+    if (strncmp(keyref, "@t", key_location_len) == 0 ||
+        strncmp(keyref, "@p", key_location_len) == 0 ||
+        strncmp(keyref, "@s", key_location_len) == 0 ||
+        strncmp(keyref, "@u", key_location_len) == 0 ||
+        strncmp(keyref, "@g", key_location_len) == 0 ||
+        strncmp(keyref, "@us", key_location_len) == 0)
+        return 1;
+
     return 0;
 }
 
-int e4crypt_check_passwd(const char* path, const char* password)
+static int is_dir_empty(const char *dirname)
 {
-    UnencryptedProperties props(path);
-    if (props.Get<std::string>(properties::key).empty()) {
-        KLOG_INFO(TAG, "No master key, so not ext4enc\n");
-        return -1;
-    }
-
-    auto actual_password = props.Get<std::string>(properties::password);
-
-    if (actual_password == password) {
-        s_password_store[path] = password;
-        return 0;
-    } else {
-        return -1;
+    int n = 0;
+    struct dirent *d;
+    DIR *dir;
+
+    dir = opendir(dirname);
+    while ((d = readdir(dir)) != NULL) {
+        if (strcmp(d->d_name, "lost+found") == 0) {
+            // Skip lost+found directory
+        } else if (++n > 2) {
+            break;
+        }
     }
+    closedir(dir);
+    return n <= 2;
 }
 
-int e4crypt_restart(const char* path)
+int do_policy_set(const char *directory, const char *policy)
 {
-    int rc = 0;
+    struct stat st;
+    ssize_t ret;
 
-    KLOG_INFO(TAG, "ext4 restart called on %s\n", path);
-    property_set("vold.decrypt", "trigger_reset_main");
-    KLOG_INFO(TAG, "Just asked init to shut down class main\n");
-    sleep(2);
+    if (!is_keyref_valid(policy)) {
+        KLOG_ERROR(TAG, "Policy has invalid format.\n");
+        return -EINVAL;
+    }
 
-    std::string tmp_path = std::string() + path + "/tmp_mnt";
+    if (!is_path_valid(directory)) {
+        return -EINVAL;
+    }
 
-    // ext4enc:TODO add retry logic
-    rc = umount(tmp_path.c_str());
-    if (rc) {
-        KLOG_ERROR(TAG, "umount %s failed with rc %d, msg %s\n",
-                   tmp_path.c_str(), rc, strerror(errno));
-        return rc;
+    stat(directory, &st);
+    if (!S_ISDIR(st.st_mode)) {
+        KLOG_ERROR(TAG, "Can only set policy on a directory (%s)\n", directory);
+        return -EINVAL;
     }
 
-    // ext4enc:TODO add retry logic
-    rc = umount(path);
-    if (rc) {
-        KLOG_ERROR(TAG, "umount %s failed with rc %d, msg %s\n",
-                   path, rc, strerror(errno));
-        return rc;
+    if (!is_dir_empty(directory)) {
+        KLOG_ERROR(TAG, "Can only set policy on an empty directory (%s)\n",
+                   directory);
+        return -EINVAL;
     }
 
+    ret = lsetxattr(directory, XATTR_NAME_ENCRYPTION_POLICY, policy,
+                    strlen(policy), 0);
+
+    if (ret) {
+        KLOG_ERROR(TAG, "Failed to set encryption policy for %s: %s\n",
+                   directory, strerror(errno));
+        return -EINVAL;
+    }
+
+    KLOG_INFO(TAG, "Encryption policy for %s is set to %s\n", directory, policy);
     return 0;
 }
 
-const char* e4crypt_get_password(const char* path)
+bool e4crypt_non_default_key(const char* dir)
 {
-    // ext4enc:TODO scrub password after timeout
-    auto i = s_password_store.find(path);
-    if (i == s_password_store.end()) {
-        return 0;
-    } else {
-        return i->second.c_str();
-    }
+    UnencryptedProperties props(dir);
+    return props.Get<int>(properties::is_default, 1) != 1;
 }
diff --git a/ext4_utils/ext4_crypt_init_extensions.cpp b/ext4_utils/ext4_crypt_init_extensions.cpp
index 284437f9..3b7df6dd 100644
--- a/ext4_utils/ext4_crypt_init_extensions.cpp
+++ b/ext4_utils/ext4_crypt_init_extensions.cpp
@@ -1,12 +1,10 @@
 #define TAG "ext4_utils"
 
-#include "ext4_crypt.h"
+#include "ext4_crypt_init_extensions.h"
 
 #include <string>
-#include <fstream>
-#include <iomanip>
-#include <sstream>
 
+#include <dirent.h>
 #include <errno.h>
 #include <sys/mount.h>
 #include <sys/stat.h>
@@ -16,29 +14,26 @@
 #include <cutils/sockets.h>
 #include <poll.h>
 
+#include "key_control.h"
 #include "unencrypted_properties.h"
 
-// ext4enc:TODO Include structure from somewhere sensible
-// MUST be in sync with ext4_crypto.c in kernel
-#define EXT4_MAX_KEY_SIZE 76
-struct ext4_encryption_key {
-        uint32_t mode;
-        char raw[EXT4_MAX_KEY_SIZE];
-        uint32_t size;
-};
-
-static const std::string keyring = "@s";
 static const std::string arbitrary_sequence_number = "42";
-static const int vold_command_timeout_ms = 10 * 1000;
-
-static key_serial_t device_keyring = -1;
+static const int vold_command_timeout_ms = 60 * 1000;
 
 static std::string vold_command(std::string const& command)
 {
     KLOG_INFO(TAG, "Running command %s\n", command.c_str());
-    int sock = socket_local_client("vold",
+    int sock = -1;
+
+    while (true) {
+        sock = socket_local_client("vold",
                                    ANDROID_SOCKET_NAMESPACE_RESERVED,
                                    SOCK_STREAM);
+        if (sock >= 0) {
+            break;
+        }
+        usleep(10000);
+    }
 
     if (sock < 0) {
         KLOG_INFO(TAG, "Cannot open vold, failing command\n");
@@ -97,52 +92,35 @@ static std::string vold_command(std::string const& command)
 int e4crypt_create_device_key(const char* dir,
                               int ensure_dir_exists(const char*))
 {
+    // Already encrypted with password? If so bail
+    std::string temp_folder = std::string() + dir + "/tmp_mnt";
+    DIR* temp_dir = opendir(temp_folder.c_str());
+    if (temp_dir) {
+        closedir(temp_dir);
+        return 0;
+    }
+
     // Make sure folder exists. Use make_dir to set selinux permissions.
     KLOG_INFO(TAG, "Creating test device key\n");
-    UnencryptedProperties props(dir);
-    if (ensure_dir_exists(props.GetPath().c_str())) {
+    if (ensure_dir_exists(UnencryptedProperties::GetPath(dir).c_str())) {
         KLOG_ERROR(TAG, "Failed to create %s with error %s\n",
-                   props.GetPath().c_str(), strerror(errno));
+                   UnencryptedProperties::GetPath(dir).c_str(),
+                   strerror(errno));
         return -1;
     }
 
-    if (props.Get<std::string>(properties::key).empty()) {
-        // Create new key since it doesn't already exist
-        std::ifstream urandom("/dev/urandom", std::ifstream::binary);
-        if (!urandom) {
-            KLOG_ERROR(TAG, "Failed to open /dev/urandom\n");
-            return -1;
-        }
-
-        // ext4enc:TODO Don't hardcode 32
-        std::string key_material(32, '\0');
-        urandom.read(&key_material[0], key_material.length());
-        if (!urandom) {
-            KLOG_ERROR(TAG, "Failed to read random bytes\n");
-            return -1;
-        }
-
-        if (!props.Set(properties::key, key_material)) {
-            KLOG_ERROR(TAG, "Failed to write key material\n");
-            return -1;
-        }
-    }
-
-    if (!props.Remove(properties::ref)) {
-        KLOG_ERROR(TAG, "Failed to remove key ref\n");
-        return -1;
-    }
+    auto result = vold_command("cryptfs enablefilecrypto");
+    // ext4enc:TODO proper error handling
+    KLOG_INFO(TAG, "enablefilecrypto returned with result %s\n",
+              result.c_str());
 
     return 0;
 }
 
 int e4crypt_install_keyring()
 {
-    device_keyring = add_key("keyring",
-                             "e4crypt",
-                             0,
-                             0,
-                             KEY_SPEC_SESSION_KEYRING);
+    key_serial_t device_keyring = add_key("keyring", "e4crypt", 0, 0,
+                                          KEY_SPEC_SESSION_KEYRING);
 
     if (device_keyring == -1) {
         KLOG_ERROR(TAG, "Failed to create keyring\n");
@@ -162,83 +140,6 @@ int e4crypt_install_keyring()
     return 0;
 }
 
-int e4crypt_install_key(const char* dir)
-{
-    UnencryptedProperties props(dir);
-    auto key = props.Get<std::string>(properties::key);
-
-    // Get password to decrypt as needed
-    if (e4crypt_non_default_key(dir)) {
-        std::string result = vold_command("cryptfs getpw");
-        // result is either
-        // 200 0 -1
-        // or
-        // 200 0 {{sensitive}} 0001020304
-        // where 0001020304 is hex encoding of password
-        std::istringstream i(result);
-        std::string bit;
-        i >> bit;
-        if (bit != "200") {
-            KLOG_ERROR(TAG, "Expecting 200\n");
-            return -1;
-        }
-
-        i >> bit;
-        if (bit != arbitrary_sequence_number) {
-            KLOG_ERROR(TAG, "Expecting %s\n", arbitrary_sequence_number.c_str());
-            return -1;
-        }
-
-        i >> bit;
-        if (bit != "{{sensitive}}") {
-            KLOG_INFO(TAG, "Not encrypted\n");
-            return -1;
-        }
-
-        i >> bit;
-    }
-
-    // Add key to keyring
-    ext4_encryption_key ext4_key = {0, {0}, 0};
-    if (key.length() > sizeof(ext4_key.raw)) {
-        KLOG_ERROR(TAG, "Key too long\n");
-        return -1;
-    }
-
-    ext4_key.mode = 0;
-    memcpy(ext4_key.raw, &key[0], key.length());
-    ext4_key.size = key.length();
-
-    // ext4enc:TODO Use better reference not 1234567890
-    key_serial_t key_id = add_key("logon", "ext4-key:1234567890",
-                                  (void*)&ext4_key, sizeof(ext4_key),
-                                  device_keyring);
-
-    if (key_id == -1) {
-        KLOG_ERROR(TAG, "Failed to insert key into keyring with error %s\n",
-                   strerror(errno));
-        return -1;
-    }
-
-    KLOG_INFO(TAG, "Added key %d to keyring %d in process %d\n",
-              key_id, device_keyring, getpid());
-
-    // ext4enc:TODO set correct permissions
-    long result = keyctl_setperm(key_id, 0x3f3f3f3f);
-    if (result) {
-        KLOG_ERROR(TAG, "KEYCTL_SETPERM failed with error %ld\n", result);
-        return -1;
-    }
-
-    // Save reference to key so we can set policy later
-    if (!props.Set(properties::ref, "ext4-key:1234567890")) {
-        KLOG_ERROR(TAG, "Cannot save key reference\n");
-        return -1;
-    }
-
-    return 0;
-}
-
 int e4crypt_set_directory_policy(const char* dir)
 {
     // Only set policy on first level /data directories
@@ -250,12 +151,12 @@ int e4crypt_set_directory_policy(const char* dir)
     }
 
     UnencryptedProperties props("/data");
-    std::string ref = props.Get<std::string>(properties::ref);
-    std::string policy = keyring + "." + ref;
+    std::string policy = props.Get<std::string>(properties::ref);
     KLOG_INFO(TAG, "Setting policy %s\n", policy.c_str());
     int result = do_policy_set(dir, policy.c_str());
     if (result) {
-        KLOG_ERROR(TAG, "Setting policy on %s failed!\n", dir);
+        KLOG_ERROR(TAG, "Setting %s policy on %s failed!\n",
+                   policy.c_str(), dir);
         return -1;
     }
 
diff --git a/ext4_utils/ext4_crypt_init_extensions.h b/ext4_utils/ext4_crypt_init_extensions.h
new file mode 100644
index 00000000..17f5b2e0
--- /dev/null
+++ b/ext4_utils/ext4_crypt_init_extensions.h
@@ -0,0 +1,15 @@
+#include <sys/cdefs.h>
+#include <stdbool.h>
+
+__BEGIN_DECLS
+
+// These functions assume they are being called from init
+// They will not operate properly outside of init
+int e4crypt_install_keyring();
+int e4crypt_create_device_key(const char* path,
+                              int ensure_dir_exists(const char* dir));
+int e4crypt_set_directory_policy(const char* path);
+bool e4crypt_non_default_key(const char* path);
+int do_policy_set(const char *directory, const char *policy);
+
+__END_DECLS
diff --git a/ext4_utils/key_control.cpp b/ext4_utils/key_control.cpp
new file mode 100644
index 00000000..3d775b7f
--- /dev/null
+++ b/ext4_utils/key_control.cpp
@@ -0,0 +1,44 @@
+#include "key_control.h"
+
+#include <stdarg.h>
+#include <unistd.h>
+#include <sys/syscall.h>
+
+/* keyring keyctl commands */
+#define KEYCTL_SETPERM        5 /* set permissions for a key in a keyring */
+#define KEYCTL_UNLINK         9 /* unlink a key from a keyring */
+#define KEYCTL_SEARCH        10 /* search for a key in a keyring */
+
+static long keyctl(int cmd, ...)
+{
+    va_list va;
+    unsigned long arg2, arg3, arg4, arg5;
+
+    va_start(va, cmd);
+    arg2 = va_arg(va, unsigned long);
+    arg3 = va_arg(va, unsigned long);
+    arg4 = va_arg(va, unsigned long);
+    arg5 = va_arg(va, unsigned long);
+    va_end(va);
+    return syscall(__NR_keyctl, cmd, arg2, arg3, arg4, arg5);
+}
+
+key_serial_t add_key(const char *type,
+                     const char *description,
+                     const void *payload,
+                     size_t plen,
+                     key_serial_t ringid)
+{
+    return syscall(__NR_add_key, type, description, payload, plen, ringid);
+}
+
+long keyctl_setperm(key_serial_t id, int permissions)
+{
+    return keyctl(KEYCTL_SETPERM, id, permissions);
+}
+
+long keyctl_search(key_serial_t ringid, const char *type,
+                   const char *description, key_serial_t destringid)
+{
+    return keyctl(KEYCTL_SEARCH, ringid, type, description, destringid);
+}
diff --git a/ext4_utils/ext4_crypt.h b/ext4_utils/key_control.h
index cc692735..8e6e32ba 100644
--- a/ext4_utils/ext4_crypt.h
+++ b/ext4_utils/key_control.h
@@ -1,28 +1,7 @@
-#include <stdbool.h>
 #include <sys/cdefs.h>
 #include <sys/types.h>
 
 __BEGIN_DECLS
-// These functions assume they are being called from init
-// They will not operate properly outside of init
-int e4crypt_install_keyring();
-int e4crypt_install_key(const char* dir);
-int e4crypt_create_device_key(const char* dir,
-                              int ensure_dir_exists(const char* dir));
-
-// General functions
-bool e4crypt_non_default_key(const char* dir);
-int e4crypt_set_directory_policy(const char* dir);
-int e4crypt_main(int argc, char* argv[]);
-int e4crypt_change_password(const char* path, int crypt_type,
-                            const char* password);
-int e4crypt_get_password_type(const char* path);
-int e4crypt_crypto_complete(const char* dir);
-int e4crypt_check_passwd(const char* dir, const char* password);
-const char* e4crypt_get_password(const char* dir);
-int e4crypt_restart(const char* dir);
-
-// Key functions. ext4enc:TODO Move to own file
 
 // ext4enc:TODO - get these keyring standard definitions from proper system file
 // keyring serial number type
@@ -44,7 +23,7 @@ key_serial_t add_key(const char *type,
 
 long keyctl_setperm(key_serial_t id, int permissions);
 
-// Set policy on directory
-int do_policy_set(const char *directory, const char *policy);
+long keyctl_search(key_serial_t ringid, const char *type,
+                   const char *description, key_serial_t destringid);
 
 __END_DECLS
diff --git a/ext4_utils/unencrypted_properties.cpp b/ext4_utils/unencrypted_properties.cpp
index bef7c57b..5086c64b 100644
--- a/ext4_utils/unencrypted_properties.cpp
+++ b/ext4_utils/unencrypted_properties.cpp
@@ -1,12 +1,12 @@
 #include "unencrypted_properties.h"
 
 #include <sys/stat.h>
+#include <dirent.h>
 
 namespace properties {
     const char* key = "key";
     const char* ref = "ref";
-    const char* type = "type";
-    const char* password = "password";
+    const char* is_default = "is_default";
 }
 
 namespace
@@ -14,9 +14,20 @@ namespace
     const char* unencrypted_folder = "unencrypted";
 }
 
+std::string UnencryptedProperties::GetPath(const char* device)
+{
+    return std::string() + device + "/" + unencrypted_folder;
+}
+
 UnencryptedProperties::UnencryptedProperties(const char* device)
-  : folder_(std::string() + device + "/" + unencrypted_folder)
+  : folder_(GetPath(device))
 {
+    DIR* dir = opendir(folder_.c_str());
+    if (dir) {
+        closedir(dir);
+    } else {
+        folder_.clear();
+    }
 }
 
 UnencryptedProperties::UnencryptedProperties()
@@ -24,7 +35,7 @@ UnencryptedProperties::UnencryptedProperties()
 }
 
 template<> std::string UnencryptedProperties::Get(const char* name,
-                                      std::string default_value)
+                                      std::string default_value) const
 {
     if (!OK()) return default_value;
     std::ifstream i(folder_ + "/" + name, std::ios::binary);
@@ -56,18 +67,18 @@ template<> bool UnencryptedProperties::Set(const char* name, std::string const&
     return !o.fail();
 }
 
-UnencryptedProperties UnencryptedProperties::GetChild(const char* name)
+UnencryptedProperties UnencryptedProperties::GetChild(const char* name) const
 {
-    UnencryptedProperties e4p;
-    if (!OK()) return e4p;
+    UnencryptedProperties up;
+    if (!OK()) return up;
 
     std::string directory(folder_ + "/" + name);
     if (mkdir(directory.c_str(), 700) == -1 && errno != EEXIST) {
-        return e4p;
+        return up;
     }
 
-    e4p.folder_ = directory;
-    return e4p;
+    up.folder_ = directory;
+    return up;
 }
 
 bool UnencryptedProperties::Remove(const char* name)
diff --git a/ext4_utils/unencrypted_properties.h b/ext4_utils/unencrypted_properties.h
index 80f41df4..d0f6da1a 100644
--- a/ext4_utils/unencrypted_properties.h
+++ b/ext4_utils/unencrypted_properties.h
@@ -5,8 +5,7 @@
 namespace properties {
     extern const char* key;
     extern const char* ref;
-    extern const char* type;
-    extern const char* password;
+    extern const char* is_default;
 }
 
 /**
@@ -18,34 +17,38 @@ namespace properties {
 class UnencryptedProperties
 {
 public:
+    // Get path of folder. Must create before using any properties
+    // This is to allow proper setting of SELinux policy
+    static std::string GetPath(const char* device);
+
     // Opens properties folder on named device.
-    // If folder does not exist, construction will succeed, but all
+    // If folder does not exist, OK will return false, all
     // getters will return default properties and setters will fail.
     UnencryptedProperties(const char* device);
 
     // Get named object. Return default if object does not exist or error.
-    template<typename t> t Get(const char* name, t default_value = t());
+    template<typename t> t Get(const char* name, t default_value = t()) const;
 
     // Set named object. Return true if success, false otherwise
     template<typename t> bool Set(const char* name, t const& value);
 
     // Get child properties
-    UnencryptedProperties GetChild(const char* name);
+    UnencryptedProperties GetChild(const char* name) const;
 
     // Remove named object
     bool Remove(const char* name);
 
-    // Get path of folder
-    std::string const& GetPath() const {return folder_;}
+    // Does folder exist?
+    bool OK() const;
+
 private:
     UnencryptedProperties();
-    bool OK() const;
     std::string folder_;
 };
 
 
 template<typename t> t UnencryptedProperties::Get(const char* name,
-                                                  t default_value)
+                                                  t default_value) const
 {
     if (!OK()) return default_value;
     t value = default_value;
@@ -64,7 +67,7 @@ template<typename t> bool UnencryptedProperties::Set(const char* name,
 
 // Specialized getters/setters for strings
 template<> std::string UnencryptedProperties::Get(const char* name,
-                                      std::string default_value);
+                                      std::string default_value) const;
 
 template<> bool UnencryptedProperties::Set(const char* name,
                                            std::string const& value);