Home | History | Annotate | Download | only in ext4_utils 
      1 #define TAG "ext4_utils"
      2 
      3 #include "ext4_crypt_init_extensions.h"
      4 
      5 #include <string>
      6 
      7 #include <dirent.h>
      8 #include <errno.h>
      9 #include <sys/mount.h>
     10 #include <sys/stat.h>
     11 
     12 #include <cutils/klog.h>
     13 #include <cutils/properties.h>
     14 #include <cutils/sockets.h>
     15 #include <poll.h>
     16 
     17 #include "key_control.h"
     18 #include "unencrypted_properties.h"
     19 
     20 static const std::string arbitrary_sequence_number = "42";
     21 static const int vold_command_timeout_ms = 60 * 1000;
     22 
     23 static std::string vold_command(std::string const& command)
     24 {
     25     KLOG_INFO(TAG, "Running command %s\n", command.c_str());
     26     int sock = -1;
     27 
     28     while (true) {
     29         sock = socket_local_client("cryptd",
     30                                    ANDROID_SOCKET_NAMESPACE_RESERVED,
     31                                    SOCK_STREAM);
     32         if (sock >= 0) {
     33             break;
     34         }
     35         usleep(10000);
     36     }
     37 
     38     if (sock < 0) {
     39         KLOG_INFO(TAG, "Cannot open vold, failing command\n");
     40         return "";
     41     }
     42 
     43     class CloseSocket
     44     {
     45         int sock_;
     46     public:
     47         CloseSocket(int sock) : sock_(sock) {}
     48         ~CloseSocket() { close(sock_); }
     49     };
     50 
     51     CloseSocket cs(sock);
     52 
     53     // Use arbitrary sequence number. This should only be used when the
     54     // framework is down, so this is (mostly) OK.
     55     std::string actual_command = arbitrary_sequence_number + " " + command;
     56     if (write(sock, actual_command.c_str(), actual_command.size() + 1) < 0) {
     57         KLOG_ERROR(TAG, "Cannot write command\n");
     58         return "";
     59     }
     60 
     61     struct pollfd poll_sock = {sock, POLLIN, 0};
     62 
     63     int rc = TEMP_FAILURE_RETRY(poll(&poll_sock, 1, vold_command_timeout_ms));
     64     if (rc < 0) {
     65         KLOG_ERROR(TAG, "Error in poll %s\n", strerror(errno));
     66         return "";
     67     }
     68 
     69     if (!(poll_sock.revents & POLLIN)) {
     70         KLOG_ERROR(TAG, "Timeout\n");
     71         return "";
     72     }
     73     char buffer[4096];
     74     memset(buffer, 0, sizeof(buffer));
     75     rc = TEMP_FAILURE_RETRY(read(sock, buffer, sizeof(buffer)));
     76     if (rc <= 0) {
     77         if (rc == 0) {
     78             KLOG_ERROR(TAG, "Lost connection to Vold - did it crash?\n");
     79         } else {
     80             KLOG_ERROR(TAG, "Error reading data (%s)\n", strerror(errno));
     81         }
     82         return "";
     83     }
     84 
     85     // We don't truly know that this is the correct result. However,
     86     // since this will only be used when the framework is down,
     87     // it should be OK unless someone is running vdc at the same time.
     88     // Worst case we force a reboot in the very rare synchronization
     89     // error
     90     return std::string(buffer, rc);
     91 }
     92 
     93 int e4crypt_create_device_key(const char* dir,
     94                               int ensure_dir_exists(const char*))
     95 {
     96     // Already encrypted with password? If so bail
     97     std::string temp_folder = std::string() + dir + "/tmp_mnt";
     98     DIR* temp_dir = opendir(temp_folder.c_str());
     99     if (temp_dir) {
    100         closedir(temp_dir);
    101         return 0;
    102     }
    103 
    104     // Make sure folder exists. Use make_dir to set selinux permissions.
    105     if (ensure_dir_exists(UnencryptedProperties::GetPath(dir).c_str())) {
    106         KLOG_ERROR(TAG, "Failed to create %s with error %s\n",
    107                    UnencryptedProperties::GetPath(dir).c_str(),
    108                    strerror(errno));
    109         return -1;
    110     }
    111 
    112     auto result = vold_command("cryptfs enablefilecrypto");
    113     // ext4enc:TODO proper error handling
    114     KLOG_INFO(TAG, "enablefilecrypto returned with result %s\n",
    115               result.c_str());
    116 
    117     return 0;
    118 }
    119 
    120 int e4crypt_install_keyring()
    121 {
    122     key_serial_t device_keyring = add_key("keyring", "e4crypt", 0, 0,
    123                                           KEY_SPEC_SESSION_KEYRING);
    124 
    125     if (device_keyring == -1) {
    126         KLOG_ERROR(TAG, "Failed to create keyring\n");
    127         return -1;
    128     }
    129 
    130     KLOG_INFO(TAG, "Keyring created wth id %d in process %d\n",
    131               device_keyring, getpid());
    132 
    133     return 0;
    134 }
    135 
    136 int e4crypt_set_directory_policy(const char* dir)
    137 {
    138     // Only set policy on first level /data directories
    139     // To make this less restrictive, consider using a policy file.
    140     // However this is overkill for as long as the policy is simply
    141     // to apply a global policy to all /data folders created via makedir
    142     if (!dir || strncmp(dir, "/data/", 6) || strchr(dir + 6, '/')) {
    143         return 0;
    144     }
    145 
    146     UnencryptedProperties props("/data");
    147     std::string policy = props.Get<std::string>(properties::ref);
    148     if (policy.empty()) {
    149         return 0;
    150     }
    151 
    152     KLOG_INFO(TAG, "Setting policy on %s\n", dir);
    153     int result = do_policy_set(dir, policy.c_str(), policy.size());
    154     if (result) {
    155         KLOG_ERROR(TAG, "Setting %s policy on %s failed!\n",
    156                    policy.c_str(), dir);
    157         return -1;
    158     }
    159 
    160     return 0;
    161 }
    162