Merge "Revert "Securely encrypt the master key""

Android.mk

@@ -15,7 +15,6 @@ common_src_files := \
 	Devmapper.cpp \
 	ResponseCode.cpp \
 	CheckBattery.cpp \
-	Ext4Crypt.cpp \
 	VoldUtil.c \
 	fstrim.c \
 	cryptfs.c

CommandListener.cpp

@@ -619,14 +619,6 @@ int CommandListener::CryptfsCmd::runCommand(SocketClient *cli,
                 Process::killProcessesWithOpenFiles(DATA_MNT_POINT, 2);
             }
         }
-    } else if (!strcmp(argv[1], "enablefilecrypto")) {
-        const char* syntax = "Usage: cryptfs enablefilecrypto";
-        if (argc != 2) {
-            cli->sendMsg(ResponseCode::CommandSyntaxError, syntax, false);
-            return 0;
-        }
-        dumpArgs(argc, argv, -1);
-        rc = cryptfs_enable_file();
     } else if (!strcmp(argv[1], "changepw")) {
         const char* syntax = "Usage: cryptfs changepw "
                              "default|password|pin|pattern [newpasswd]";

Ext4Crypt.cpp

@@ -1,377 +0,0 @@
-#include "Ext4Crypt.h"
-
-#include <string>
-#include <fstream>
-#include <map>
-
-#include <errno.h>
-#include <sys/mount.h>
-#include <cutils/properties.h>
-
-#include "unencrypted_properties.h"
-#include "key_control.h"
-#include "cryptfs.h"
-
-#define LOG_TAG "Ext4Crypt"
-#include "cutils/log.h"
-#include <cutils/klog.h>
-
-namespace {
-    // Key length in bits
-    const int key_length = 128;
-
-    // How is device encrypted
-    struct keys {
-        std::string master_key;
-        std::string password;
-    };
-    std::map<std::string, keys> s_key_store;
-
-    // ext4enc:TODO Include structure from somewhere sensible
-    // MUST be in sync with ext4_crypto.c in kernel
-    const int EXT4_MAX_KEY_SIZE = 76;
-    struct ext4_encryption_key {
-            uint32_t mode;
-            char raw[EXT4_MAX_KEY_SIZE];
-            uint32_t size;
-    };
-
-    namespace tag {
-        const char* magic = "magic";
-        const char* major_version = "major_version";
-        const char* minor_version = "minor_version";
-        const char* flags = "flags";
-        const char* crypt_type = "crypt_type";
-        const char* failed_decrypt_count = "failed_decrypt_count";
-        const char* crypto_type_name = "crypto_type_name";
-        const char* master_key = "master_key";
-        const char* salt = "salt";
-        const char* kdf_type = "kdf_type";
-        const char* N_factor = "N_factor";
-        const char* r_factor = "r_factor";
-        const char* p_factor = "p_factor";
-        const char* keymaster_blob = "keymaster_blob";
-        const char* scrypted_intermediate_key = "scrypted_intermediate_key";
-    }
-}
-
-static int put_crypt_ftr_and_key(const crypt_mnt_ftr& crypt_ftr,
-                                 UnencryptedProperties& props)
-{
-    SLOGI("Putting crypt footer");
-
-    bool success = props.Set<int>(tag::magic, crypt_ftr.magic)
-      && props.Set<int>(tag::major_version, crypt_ftr.major_version)
-      && props.Set<int>(tag::minor_version, crypt_ftr.minor_version)
-      && props.Set<int>(tag::flags, crypt_ftr.flags)
-      && props.Set<int>(tag::crypt_type, crypt_ftr.crypt_type)
-      && props.Set<int>(tag::failed_decrypt_count,
-                        crypt_ftr.failed_decrypt_count)
-      && props.Set<std::string>(tag::crypto_type_name,
-                                std::string(reinterpret_cast<const char*>(crypt_ftr.crypto_type_name)))
-      && props.Set<std::string>(tag::master_key,
-                                std::string((const char*) crypt_ftr.master_key,
-                                            crypt_ftr.keysize))
-      && props.Set<std::string>(tag::salt,
-                                std::string((const char*) crypt_ftr.salt,
-                                            SALT_LEN))
-      && props.Set<int>(tag::kdf_type, crypt_ftr.kdf_type)
-      && props.Set<int>(tag::N_factor, crypt_ftr.N_factor)
-      && props.Set<int>(tag::r_factor, crypt_ftr.r_factor)
-      && props.Set<int>(tag::p_factor, crypt_ftr.p_factor)
-      && props.Set<std::string>(tag::keymaster_blob,
-                                std::string((const char*) crypt_ftr.keymaster_blob,
-                                            crypt_ftr.keymaster_blob_size))
-      && props.Set<std::string>(tag::scrypted_intermediate_key,
-                                std::string((const char*) crypt_ftr.scrypted_intermediate_key,
-                                            SCRYPT_LEN));
-    return success ? 0 : -1;
-}
-
-static int get_crypt_ftr_and_key(crypt_mnt_ftr& crypt_ftr,
-                                 const UnencryptedProperties& props)
-{
-    memset(&crypt_ftr, 0, sizeof(crypt_ftr));
-    crypt_ftr.magic = props.Get<int>(tag::magic);
-    crypt_ftr.major_version = props.Get<int>(tag::major_version);
-    crypt_ftr.minor_version = props.Get<int>(tag::minor_version);
-    crypt_ftr.flags = props.Get<int>(tag::flags);
-    crypt_ftr.crypt_type = props.Get<int>(tag::crypt_type);
-    crypt_ftr.failed_decrypt_count = props.Get<int>(tag::failed_decrypt_count);
-    std::string crypto_type_name = props.Get<std::string>(tag::crypto_type_name);
-    strlcpy(reinterpret_cast<char*>(crypt_ftr.crypto_type_name),
-            crypto_type_name.c_str(),
-            sizeof(crypt_ftr.crypto_type_name));
-    std::string master_key = props.Get<std::string>(tag::master_key);
-    crypt_ftr.keysize = master_key.size();
-    if (crypt_ftr.keysize > sizeof(crypt_ftr.master_key)) {
-        SLOGE("Master key size too long");
-        return -1;
-    }
-    memcpy(crypt_ftr.master_key, &master_key[0], crypt_ftr.keysize);
-    std::string salt = props.Get<std::string>(tag::salt);
-    if (salt.size() != SALT_LEN) {
-        SLOGE("Salt wrong length");
-        return -1;
-    }
-    memcpy(crypt_ftr.salt, &salt[0], SALT_LEN);
-    crypt_ftr.kdf_type = props.Get<int>(tag::kdf_type);
-    crypt_ftr.N_factor = props.Get<int>(tag::N_factor);
-    crypt_ftr.r_factor = props.Get<int>(tag::r_factor);
-    crypt_ftr.p_factor = props.Get<int>(tag::p_factor);
-    std::string keymaster_blob = props.Get<std::string>(tag::keymaster_blob);
-    crypt_ftr.keymaster_blob_size = keymaster_blob.size();
-    if (crypt_ftr.keymaster_blob_size > sizeof(crypt_ftr.keymaster_blob)) {
-        SLOGE("Keymaster blob too long");
-        return -1;
-    }
-    memcpy(crypt_ftr.keymaster_blob, &keymaster_blob[0],
-           crypt_ftr.keymaster_blob_size);
-    std::string scrypted_intermediate_key = props.Get<std::string>(tag::scrypted_intermediate_key);
-    if (scrypted_intermediate_key.size() != SCRYPT_LEN) {
-        SLOGE("scrypted intermediate key wrong length");
-        return -1;
-    }
-    memcpy(crypt_ftr.scrypted_intermediate_key, &scrypted_intermediate_key[0],
-           SCRYPT_LEN);
-
-    return 0;
-}
-
-static UnencryptedProperties GetProps(const char* path)
-{
-    return UnencryptedProperties(path);
-}
-
-static UnencryptedProperties GetAltProps(const char* path)
-{
-    return UnencryptedProperties((std::string() + path + "/tmp_mnt").c_str());
-}
-
-static UnencryptedProperties GetPropsOrAltProps(const char* path)
-{
-    UnencryptedProperties props = GetProps(path);
-    if (props.OK()) {
-        return props;
-    }
-    return GetAltProps(path);
-}
-
-int e4crypt_enable(const char* path)
-{
-    // Already enabled?
-    if (s_key_store.find(path) != s_key_store.end()) {
-        return 0;
-    }
-
-    // Not an encryptable device?
-    UnencryptedProperties key_props = GetProps(path).GetChild(properties::key);
-    if (!key_props.OK()) {
-        return 0;
-    }
-
-    if (key_props.Get<std::string>(tag::master_key).empty()) {
-        crypt_mnt_ftr ftr;
-        if (cryptfs_create_default_ftr(&ftr, key_length)) {
-            SLOGE("Failed to create crypto footer");
-            return -1;
-        }
-
-        if (put_crypt_ftr_and_key(ftr, key_props)) {
-            SLOGE("Failed to write crypto footer");
-            return -1;
-        }
-
-        crypt_mnt_ftr ftr2;
-        if (get_crypt_ftr_and_key(ftr2, key_props)) {
-            SLOGE("Failed to read crypto footer back");
-            return -1;
-        }
-
-        if (memcmp(&ftr, &ftr2, sizeof(ftr)) != 0) {
-            SLOGE("Crypto footer not correctly written");
-            // ex4enc:TODO why is this failing?
-            //return -1;
-        }
-    }
-
-    if (!UnencryptedProperties(path).Remove(properties::ref)) {
-        SLOGE("Failed to remove key ref");
-        return -1;
-    }
-
-    return e4crypt_check_passwd(path, "");
-}
-
-int e4crypt_change_password(const char* path, int crypt_type,
-                            const char* password)
-{
-    SLOGI("e4crypt_change_password");
-
-    UnencryptedProperties key_props = GetProps(path).GetChild(properties::key);
-
-    crypt_mnt_ftr ftr;
-    if (get_crypt_ftr_and_key(ftr, key_props)) {
-        SLOGE("Failed to read crypto footer back");
-        return -1;
-    }
-
-    auto mki = s_key_store.find(path);
-    if (mki == s_key_store.end()) {
-        SLOGE("No stored master key - can't change password");
-        return -1;
-    }
-
-    const unsigned char* master_key
-        = reinterpret_cast<const unsigned char*>(&mki->second.master_key[0]);
-
-    if (cryptfs_set_password(&ftr, password, master_key)) {
-        SLOGE("Failed to set password");
-        return -1;
-    }
-
-    ftr.crypt_type = crypt_type;
-
-    if (put_crypt_ftr_and_key(ftr, key_props)) {
-        SLOGE("Failed to write crypto footer");
-        return -1;
-    }
-
-    if (!UnencryptedProperties(path).Set(properties::is_default,
-                            crypt_type == CRYPT_TYPE_DEFAULT)) {
-        SLOGE("Failed to update default flag");
-        return -1;
-    }
-
-    return 0;
-}
-
-int e4crypt_crypto_complete(const char* path)
-{
-    SLOGI("ext4 crypto complete called on %s", path);
-    UnencryptedProperties key_props
-        = GetPropsOrAltProps(path).GetChild(properties::key);
-    if (key_props.Get<std::string>(tag::master_key).empty()) {
-        SLOGI("No master key, so not ext4enc");
-        return -1;
-    }
-
-    return 0;
-}
-
-int e4crypt_check_passwd(const char* path, const char* password)
-{
-    SLOGI("e4crypt_check_password");
-
-    // ext4enc:TODO once we have password checking, fix this to be
-    // GetKeyOrAltKey
-    UnencryptedProperties props = *password ? GetAltProps(path)
-                                            : GetProps(path);
-    UnencryptedProperties key_props = props.GetChild(properties::key);
-
-    crypt_mnt_ftr ftr;
-    if (get_crypt_ftr_and_key(ftr, key_props)) {
-        SLOGE("Failed to read crypto footer back");
-        return -1;
-    }
-
-    unsigned char master_key[key_length / 8];
-    if (cryptfs_get_master_key (&ftr, password, master_key)){
-        SLOGI("Incorrect password");
-        return -1;
-    }
-
-    s_key_store[path] = keys{std::string(reinterpret_cast<char*>(master_key),
-                                         sizeof(master_key)),
-                             password};
-
-    // Install password into global keyring
-    ext4_encryption_key ext4_key = {0, {0}, key_length / 8};
-    memcpy(ext4_key.raw, master_key, ext4_key.size);
-
-    // ext4enc:TODO Use better reference not 1234567890
-    key_serial_t device_keyring = keyctl_search(KEY_SPEC_SESSION_KEYRING,
-                                                "keyring", "e4crypt", 0);
-
-    SLOGI("Found device_keyring - id is %d", device_keyring);
-
-    key_serial_t key_id = add_key("logon", "ext4-key:1234567890",
-                                  (void*)&ext4_key, sizeof(ext4_key),
-                                  device_keyring);
-
-    if (key_id == -1) {
-        SLOGE("Failed to insert key into keyring with error %s",
-              strerror(errno));
-        return -1;
-    }
-
-    SLOGI("Added key %d to keyring %d in process %d",
-          key_id, device_keyring, getpid());
-
-    // ext4enc:TODO set correct permissions
-    long result = keyctl_setperm(key_id, 0x3f3f3f3f);
-    if (result) {
-        SLOGE("KEYCTL_SETPERM failed with error %ld", result);
-        return -1;
-    }
-
-    // Save reference to key so we can set policy later
-    if (!props.Set(properties::ref, "@s.ext4-key:1234567890")) {
-        SLOGE("Cannot save key reference");
-        return -1;
-    }
-
-    return 0;
-}
-
-int e4crypt_restart(const char* path)
-{
-    SLOGI("e4crypt_restart");
-
-    int rc = 0;
-
-    SLOGI("ext4 restart called on %s", path);
-    property_set("vold.decrypt", "trigger_reset_main");
-    SLOGI("Just asked init to shut down class main");
-    sleep(2);
-
-    std::string tmp_path = std::string() + path + "/tmp_mnt";
-
-    // ext4enc:TODO add retry logic
-    rc = umount(tmp_path.c_str());
-    if (rc) {
-        SLOGE("umount %s failed with rc %d, msg %s",
-              tmp_path.c_str(), rc, strerror(errno));
-        return rc;
-    }
-
-    // ext4enc:TODO add retry logic
-    rc = umount(path);
-    if (rc) {
-        SLOGE("umount %s failed with rc %d, msg %s",
-              path, rc, strerror(errno));
-        return rc;
-    }
-
-    return 0;
-}
-
-const char* e4crypt_get_password(const char* path)
-{
-    SLOGI("e4crypt_get_password");
-
-    // ext4enc:TODO scrub password after timeout
-    auto i = s_key_store.find(path);
-    if (i == s_key_store.end()) {
-        return 0;
-    } else {
-        return i->second.password.c_str();
-    }
-}
-
-int e4crypt_get_password_type(const char* path)
-{
-    SLOGI("e4crypt_get_password_type");
-    return GetPropsOrAltProps(path).GetChild(properties::key)
-      .Get<int>(tag::crypt_type, CRYPT_TYPE_DEFAULT);
-}

Ext4Crypt.h

@@ -1,16 +0,0 @@
-#include <sys/cdefs.h>
-
-__BEGIN_DECLS
-
-// General functions
-int e4crypt_enable(const char* path);
-int e4crypt_main(int argc, char* argv[]);
-int e4crypt_change_password(const char* path, int crypt_type,
-                            const char* password);
-int e4crypt_crypto_complete(const char* path);
-int e4crypt_check_passwd(const char* path, const char* password);
-int e4crypt_get_password_type(const char* path);
-const char* e4crypt_get_password(const char* path);
-int e4crypt_restart(const char* path);
-
-__END_DECLS

cryptfs.c

@@ -53,8 +53,7 @@
 #include "VolumeManager.h"
 #include "VoldUtil.h"
 #include "crypto_scrypt.h"
-#include "Ext4Crypt.h"
+#include "ext4_crypt.h"
-#include "ext4_crypt_init_extensions.h"
 #include "ext4_utils.h"
 #include "f2fs_sparseblock.h"
 #include "CheckBattery.h"
@@ -1311,7 +1310,7 @@ static int encrypt_master_key(const char *passwd, const unsigned char *salt,
 
     /* Encrypt the master key */
     if (! EVP_EncryptUpdate(&e_ctx, encrypted_master_key, &encrypted_len,
-                            decrypted_master_key, KEY_LEN_BYTES)) {
+                              decrypted_master_key, KEY_LEN_BYTES)) {
         SLOGE("EVP_EncryptUpdate failed\n");
         return -1;
     }
@@ -1346,7 +1345,7 @@ static int encrypt_master_key(const char *passwd, const unsigned char *salt,
     return 0;
 }
 
-static int decrypt_master_key_aux(const char *passwd, unsigned char *salt,
+static int decrypt_master_key_aux(char *passwd, unsigned char *salt,
                                   unsigned char *encrypted_master_key,
                                   unsigned char *decrypted_master_key,
                                   kdf_func kdf, void *kdf_params,
@@ -1411,7 +1410,7 @@ static void get_kdf_func(struct crypt_mnt_ftr *ftr, kdf_func *kdf, void** kdf_pa
     }
 }
 
-static int decrypt_master_key(const char *passwd, unsigned char *decrypted_master_key,
+static int decrypt_master_key(char *passwd, unsigned char *decrypted_master_key,
                               struct crypt_mnt_ftr *crypt_ftr,
                               unsigned char** intermediate_key,
                               size_t* intermediate_key_size)
@@ -3805,46 +3804,3 @@ void cryptfs_clear_password()
         password_expiry_time = 0;
     }
 }
-
-int cryptfs_enable_file()
-{
-    return e4crypt_enable(DATA_MNT_POINT);
-}
-
-int cryptfs_create_default_ftr(struct crypt_mnt_ftr* crypt_ftr, __attribute__((unused))int key_length)
-{
-    if (cryptfs_init_crypt_mnt_ftr(crypt_ftr)) {
-        SLOGE("Failed to initialize crypt_ftr");
-        return -1;
-    }
-
-    if (create_encrypted_random_key(DEFAULT_PASSWORD, crypt_ftr->master_key,
-                                    crypt_ftr->salt, crypt_ftr)) {
-        SLOGE("Cannot create encrypted master key\n");
-        return -1;
-    }
-
-    //crypt_ftr->keysize = key_length / 8;
-    return 0;
-}
-
-int cryptfs_get_master_key(struct crypt_mnt_ftr* ftr, const char* password,
-                           unsigned char* master_key)
-{
-    int rc;
-
-    // ext4enc:TODO check intermediate_key to see if this is valid key
-    unsigned char* intermediate_key = 0;
-    size_t intermediate_key_size = 0;
-    rc = decrypt_master_key(password, master_key, ftr, &intermediate_key,
-                            &intermediate_key_size);
-
-    return rc;
-}
-
-int cryptfs_set_password(struct crypt_mnt_ftr* ftr, const char* password,
-                         const unsigned char* master_key)
-{
-    return encrypt_master_key(password, ftr->salt, master_key, ftr->master_key,
-                              ftr);
-}

cryptfs.h

@@ -235,7 +235,6 @@ extern "C" {
   int cryptfs_enable(char *flag, int type, char *passwd, int allow_reboot);
   int cryptfs_changepw(int type, const char *newpw);
   int cryptfs_enable_default(char *flag, int allow_reboot);
-  int cryptfs_enable_file();
   int cryptfs_setup_volume(const char *label, int major, int minor,
                            char *crypto_dev_path, unsigned int max_pathlen,
                            int *new_major, int *new_minor);
@@ -246,13 +245,6 @@ extern "C" {
   int cryptfs_get_password_type(void);
   const char* cryptfs_get_password(void);
   void cryptfs_clear_password(void);
-
-  // Functions for file encryption to use to inherit our encryption logic
-  int cryptfs_create_default_ftr(struct crypt_mnt_ftr* ftr, int key_length);
-  int cryptfs_get_master_key(struct crypt_mnt_ftr* ftr, const char* password,
-                             unsigned char* master_key);
-  int cryptfs_set_password(struct crypt_mnt_ftr* ftr, const char* password,
-                           const unsigned char* master_key);
 #ifdef __cplusplus
 }
 #endif