-#define TAG "ext4_utils"
-
-#include "ext4_crypt.h"
-
-#include <string>
-#include <fstream>
-#include <iomanip>
-#include <sstream>
-
-#include <errno.h>
-#include <sys/mount.h>
-#include <sys/stat.h>
-
-#include <cutils/klog.h>
-#include <cutils/properties.h>
-#include <cutils/sockets.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 key_serial_t device_keyring = -1;
-
-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",
- ANDROID_SOCKET_NAMESPACE_RESERVED,
- SOCK_STREAM);
-
- if (sock < 0) {
- KLOG_INFO(TAG, "Cannot open vold, failing command\n");
- return "";
- }
-
- class CloseSocket
- {
- int sock_;
- public:
- CloseSocket(int sock) : sock_(sock) {}
- ~CloseSocket() { close(sock_); }
- };
-
- CloseSocket cs(sock);
-
- // Use arbitrary sequence number. This should only be used when the
- // framework is down, so this is (mostly) OK.
- std::string actual_command = arbitrary_sequence_number + " " + command;
- if (write(sock, actual_command.c_str(), actual_command.size() + 1) < 0) {
- KLOG_ERROR(TAG, "Cannot write command\n");
- return "";
- }
-
- while (1) {
- struct timeval to;
- to.tv_sec = 10;
- to.tv_usec = 0;
-
- fd_set read_fds;
- FD_ZERO(&read_fds);
- FD_SET(sock, &read_fds);
-
- int rc = select(sock + 1, &read_fds, NULL, NULL, &to);
- if (rc < 0) {
- KLOG_ERROR(TAG, "Error in select %s\n", strerror(errno));
- return "";
- } else if (!rc) {
- KLOG_ERROR(TAG, "Timeout\n");
- return "";
- } else if (FD_ISSET(sock, &read_fds)) {
- char buffer[4096];
- memset(buffer, 0, sizeof(buffer));
- rc = read(sock, buffer, sizeof(buffer));
- if (rc <= 0) {
- if (rc == 0) {
- KLOG_ERROR(TAG, "Lost connection to Vold - did it crash?\n");
- } else {
- KLOG_ERROR(TAG, "Error reading data (%s)\n", strerror(errno));
- }
- return "";
- }
-
- // We don't truly know that this is the correct result. However,
- // since this will only be used when the framework is down,
- // it should be OK unless someone is running vdc at the same time.
- // Worst case we force a reboot in the very rare synchronization
- // error
- return std::string(buffer, rc);
- }
- }
-}
-
-int e4crypt_create_device_key(const char* dir,
- int ensure_dir_exists(const char*))
-{
- // 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())) {
- KLOG_ERROR(TAG, "Failed to create %s with error %s\n",
- props.GetPath().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;
- }
-
- return 0;
-}
-
-int e4crypt_install_keyring()
-{
- device_keyring = add_key("keyring",
- "e4crypt",
- 0,
- 0,
- KEY_SPEC_SESSION_KEYRING);
-
- if (device_keyring == -1) {
- KLOG_ERROR(TAG, "Failed to create keyring\n");
- return -1;
- }
-
- KLOG_INFO(TAG, "Keyring created wth id %d in process %d\n",
- device_keyring, getpid());
-
- // ext4enc:TODO set correct permissions
- long result = keyctl_setperm(device_keyring, 0x3f3f3f3f);
- if (result) {
- KLOG_ERROR(TAG, "KEYCTL_SETPERM failed with error %ld\n", result);
- return -1;
- }
-
- 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
- // To make this less restrictive, consider using a policy file.
- // However this is overkill for as long as the policy is simply
- // to apply a global policy to all /data folders created via makedir
- if (!dir || strncmp(dir, "/data/", 6) || strchr(dir + 6, '/')) {
- return 0;
- }
-
- UnencryptedProperties props("/data");
- std::string ref = props.Get<std::string>(properties::ref);
- std::string policy = keyring + "." + 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);
- return -1;
- }
-
- return 0;
-}
projects / project / make_ext4fs.git / commitdiff