Fix doxygen doc for libcryptsetup.h.
[platform/upstream/cryptsetup.git] / lib / libdevmapper.c
index f2e66a4..9fd01b4 100644 (file)
@@ -4,10 +4,12 @@
  * Copyright (C) 2004, Christophe Saout <christophe@saout.de>
  * Copyright (C) 2004-2007, Clemens Fruhwirth <clemens@endorphin.org>
  * Copyright (C) 2009-2012, Red Hat, Inc. All rights reserved.
+ * Copyright (C) 2009-2012, Milan Broz
  *
  * This program is free software; you can redistribute it and/or
  * modify it under the terms of the GNU General Public License
- * version 2 as published by the Free Software Foundation.
+ * as published by the Free Software Foundation; either version 2
+ * of the License, or (at your option) any later version.
  *
  * This program is distributed in the hope that it will be useful,
  * but WITHOUT ANY WARRANTY; without even the implied warranty of
 
 /* Set if dm-crypt version was probed */
 static int _dm_crypt_checked = 0;
+static int _quiet_log = 0;
 static uint32_t _dm_crypt_flags = 0;
 
-static int _dm_use_count = 0;
 static struct crypt_device *_context = NULL;
+static int _dm_use_count = 0;
 
 /* Check if we have DM flag to instruct kernel to force wipe buffers */
 #if !HAVE_DECL_DM_TASK_SECURE_DATA
@@ -81,11 +84,14 @@ static void set_dm_error(int level,
 
        va_start(va, f);
        if (vasprintf(&msg, f, va) > 0) {
-               if (level < 4) {
+               if (level < 4 && !_quiet_log) {
                        log_err(_context, msg);
                        log_err(_context, "\n");
-               } else
-                       log_dbg(msg);
+               } else {
+                       /* We do not use DM visual stack backtrace here */
+                       if (strncmp(msg, "<backtrace>", 11))
+                               log_dbg(msg);
+               }
        }
        free(msg);
        va_end(va);
@@ -142,23 +148,23 @@ static int _dm_check_versions(void)
        struct dm_task *dmt;
        struct dm_versions *target, *last_target;
        char dm_version[16];
+       int r = 0;
 
        if (_dm_crypt_checked)
                return 1;
 
+       /* Shut up DM while checking */
+       _quiet_log = 1;
+
        /* FIXME: add support to DM so it forces crypt target module load here */
        if (!(dmt = dm_task_create(DM_DEVICE_LIST_VERSIONS)))
-               return 0;
+               goto out;
 
-       if (!dm_task_run(dmt)) {
-               dm_task_destroy(dmt);
-               return 0;
-       }
+       if (!dm_task_run(dmt))
+               goto out;
 
-       if (!dm_task_get_driver_version(dmt, dm_version, sizeof(dm_version))) {
-               dm_task_destroy(dmt);
-               return 0;
-       }
+       if (!dm_task_get_driver_version(dmt, dm_version, sizeof(dm_version)))
+               goto out;
 
        target = dm_task_get_versions(dmt);
        do {
@@ -177,50 +183,65 @@ static int _dm_check_versions(void)
                target = (struct dm_versions *)((char *) target + target->next);
        } while (last_target != target);
 
-       dm_task_destroy(dmt);
-       return 1;
+       r = 1;
+       log_dbg("Device-mapper backend running with UDEV support %sabled.",
+               _dm_use_udev() ? "en" : "dis");
+out:
+       if (dmt)
+               dm_task_destroy(dmt);
+
+       _quiet_log = 0;
+       return r;
 }
 
 uint32_t dm_flags(void)
 {
-       if (!_dm_crypt_checked)
-               _dm_check_versions();
-
+       _dm_check_versions();
        return _dm_crypt_flags;
 }
 
-int dm_init(struct crypt_device *context, int check_kernel)
+/* This doesn't run any kernel checks, just set up userspace libdevmapper */
+void dm_backend_init(void)
 {
        if (!_dm_use_count++) {
-               log_dbg("Initialising device-mapper backend%s, UDEV is %sabled.",
-                       check_kernel ? "" : " (NO kernel check requested)",
-                       _dm_use_udev() ? "en" : "dis");
-               if (check_kernel && !_dm_check_versions()) {
-                       log_err(context, _("Cannot initialize device-mapper. Is dm_mod kernel module loaded?\n"));
-                       return -1;
-               }
-               if (getuid() || geteuid())
-                       log_dbg(("WARNING: Running as a non-root user. Functionality may be unavailable."));
+               log_dbg("Initialising device-mapper backend library.");
                dm_log_init(set_dm_error);
                dm_log_init_verbose(10);
        }
-
-       // FIXME: global context is not safe
-       if (context)
-               _context = context;
-
-       return 1;       /* unsafe memory */
 }
 
-void dm_exit(void)
+void dm_backend_exit(void)
 {
        if (_dm_use_count && (!--_dm_use_count)) {
                log_dbg("Releasing device-mapper backend.");
                dm_log_init_verbose(0);
                dm_log_init(NULL);
                dm_lib_release();
+       }
+}
+
+/*
+ * libdevmapper is not context friendly, switch context on every DM call.
+ * FIXME: this is not safe if called in parallel but neither is DM lib.
+ */
+static int dm_init_context(struct crypt_device *cd)
+{
+       _context = cd;
+       if (!_dm_check_versions()) {
+               if (getuid() || geteuid())
+                       log_err(cd, _("Cannot initialize device-mapper, "
+                                     "running as non-root user.\n"));
+               else
+                       log_err(cd, _("Cannot initialize device-mapper. "
+                                     "Is dm_mod kernel module loaded?\n"));
                _context = NULL;
+               return -ENOTSUP;
        }
+       return 0;
+}
+static void dm_exit_context(void)
+{
+       _context = NULL;
 }
 
 /* Return path to DM device */
@@ -256,12 +277,16 @@ static void hex_key(char *hexkey, size_t key_size, const char *key)
                sprintf(&hexkey[i * 2], "%02x", (unsigned char)key[i]);
 }
 
+/* http://code.google.com/p/cryptsetup/wiki/DMCrypt */
 static char *get_dm_crypt_params(struct crypt_dm_active_device *dmd)
 {
        int r, max_size, null_cipher = 0;
        char *params, *hexkey;
        const char *features = "";
 
+       if (!dmd)
+               return NULL;
+
        if (dmd->flags & CRYPT_ACTIVATE_ALLOW_DISCARDS) {
                if (dm_flags() & DM_DISCARDS_SUPPORTED) {
                        features = " 1 allow_discards";
@@ -283,14 +308,16 @@ static char *get_dm_crypt_params(struct crypt_dm_active_device *dmd)
                hex_key(hexkey, dmd->u.crypt.vk->keylength, dmd->u.crypt.vk->key);
 
        max_size = strlen(hexkey) + strlen(dmd->u.crypt.cipher) +
-                  strlen(dmd->u.crypt.device) + strlen(features) + 64;
+                  strlen(device_block_path(dmd->data_device)) +
+                  strlen(features) + 64;
        params = crypt_safe_alloc(max_size);
        if (!params)
                goto out;
 
        r = snprintf(params, max_size, "%s %s %" PRIu64 " %s %" PRIu64 "%s",
                     dmd->u.crypt.cipher, hexkey, dmd->u.crypt.iv_offset,
-                    dmd->u.crypt.device, dmd->u.crypt.offset, features);
+                    device_block_path(dmd->data_device), dmd->u.crypt.offset,
+                    features);
        if (r < 0 || r >= max_size) {
                crypt_safe_free(params);
                params = NULL;
@@ -299,25 +326,33 @@ out:
        crypt_safe_free(hexkey);
        return params;
 }
+
+/* http://code.google.com/p/cryptsetup/wiki/DMVerity */
 static char *get_dm_verity_params(struct crypt_params_verity *vp,
                                   struct crypt_dm_active_device *dmd)
 {
        int max_size, r;
        char *params = NULL, *hexroot = NULL, *hexsalt = NULL;
 
+       if (!vp || !dmd)
+               return NULL;
+
        hexroot = crypt_safe_alloc(dmd->u.verity.root_hash_size * 2 + 1);
        if (!hexroot)
                goto out;
        hex_key(hexroot, dmd->u.verity.root_hash_size, dmd->u.verity.root_hash);
 
-       hexsalt = crypt_safe_alloc(vp->salt_size * 2 + 1);
+       hexsalt = crypt_safe_alloc(vp->salt_size ? vp->salt_size * 2 + 1 : 2);
        if (!hexsalt)
                goto out;
-       hex_key(hexsalt, vp->salt_size, vp->salt);
+       if (vp->salt_size)
+               hex_key(hexsalt, vp->salt_size, vp->salt);
+       else
+               strncpy(hexsalt, "-", 2);
 
        max_size = strlen(hexroot) + strlen(hexsalt) +
-                  strlen(dmd->u.verity.data_device) +
-                  strlen(dmd->u.verity.hash_device) +
+                  strlen(device_block_path(dmd->data_device)) +
+                  strlen(device_block_path(dmd->u.verity.hash_device)) +
                   strlen(vp->hash_name) + 128;
 
        params = crypt_safe_alloc(max_size);
@@ -326,8 +361,8 @@ static char *get_dm_verity_params(struct crypt_params_verity *vp,
 
        r = snprintf(params, max_size,
                     "%u %s %s %u %u %" PRIu64 " %" PRIu64 " %s %s %s",
-                    vp->version, dmd->u.verity.data_device,
-                    dmd->u.verity.hash_device,
+                    vp->hash_type, device_block_path(dmd->data_device),
+                    device_block_path(dmd->u.verity.hash_device),
                     vp->data_block_size, vp->hash_block_size,
                     vp->data_size, dmd->u.verity.hash_offset,
                     vp->hash_name, hexroot, hexsalt);
@@ -335,7 +370,6 @@ static char *get_dm_verity_params(struct crypt_params_verity *vp,
                crypt_safe_free(params);
                params = NULL;
        }
-       log_dbg("TABLE: %s", params);
 out:
        crypt_safe_free(hexroot);
        crypt_safe_free(hexsalt);
@@ -412,7 +446,8 @@ error:
        return r;
 }
 
-int dm_remove_device(const char *name, int force, uint64_t size)
+int dm_remove_device(struct crypt_device *cd, const char *name,
+                    int force, uint64_t size)
 {
        int r = -EINVAL;
        int retries = force ? RETRY_COUNT : 1;
@@ -421,13 +456,14 @@ int dm_remove_device(const char *name, int force, uint64_t size)
        if (!name || (force && !size))
                return -EINVAL;
 
+       if (dm_init_context(cd))
+               return -ENOTSUP;
+
        do {
                r = _dm_simple(DM_DEVICE_REMOVE, name, 1) ? 0 : -EINVAL;
                if (--retries && r) {
                        log_dbg("WARNING: other process locked internal device %s, %s.",
                                name, retries ? "retrying remove" : "giving up");
-                       if (force && (crypt_get_debug_level() == CRYPT_LOG_DEBUG))
-                               debug_processes_using_device(name);
                        sleep(1);
                        if (force && !error_target) {
                                /* If force flag is set, replace device with error, read-only target.
@@ -445,6 +481,7 @@ int dm_remove_device(const char *name, int force, uint64_t size)
        } while (r == -EINVAL && retries);
 
        dm_task_update_nodes();
+       dm_exit_context();
 
        return r;
 }
@@ -482,7 +519,7 @@ static void dm_prepare_uuid(const char *name, const char *type, const char *uuid
 }
 
 static int _dm_create_device(const char *name, const char *type,
-                            const char *device, uint32_t flags,
+                            struct device *device, uint32_t flags,
                             const char *uuid, uint64_t size,
                             char *params, int reload)
 {
@@ -563,7 +600,7 @@ out:
        }
 
        if (r < 0 && !reload)
-               dm_remove_device(name, 0, 0);
+               _dm_simple(DM_DEVICE_REMOVE, name, 1);
 
 out_no_removal:
        if (cookie && _dm_use_udev())
@@ -578,24 +615,31 @@ out_no_removal:
        return r;
 }
 
-int dm_create_device(const char *name,
+int dm_create_device(struct crypt_device *cd, const char *name,
                     const char *type,
                     struct crypt_dm_active_device *dmd,
-                    void *params,
                     int reload)
 {
        char *table_params = NULL;
+       int r = -EINVAL;
+
+       if (!type)
+               return -EINVAL;
+
+       if (dm_init_context(cd))
+               return -ENOTSUP;
 
        if (dmd->target == DM_CRYPT)
                table_params = get_dm_crypt_params(dmd);
        else if (dmd->target == DM_VERITY)
-               table_params = get_dm_verity_params(params, dmd);
-
-       if (!table_params)
-               return -EINVAL;
+               table_params = get_dm_verity_params(dmd->u.verity.vp, dmd);
 
-       return _dm_create_device(name, type, dmd->u.crypt.device, dmd->flags,
-                                dmd->uuid, dmd->size, table_params, reload);
+       if (table_params)
+               r = _dm_create_device(name, type, dmd->data_device,
+                                     dmd->flags, dmd->uuid, dmd->size,
+                                     table_params, reload);
+       dm_exit_context();
+       return r;
 }
 
 static int dm_status_dmi(const char *name, struct dm_info *dmi,
@@ -626,11 +670,18 @@ static int dm_status_dmi(const char *name, struct dm_info *dmi,
 
        next = dm_get_next_target(dmt, next, &start, &length,
                                  &target_type, &params);
-       if (!target_type || strcmp(target_type, target) != 0 ||
-           start != 0 || next)
-               r = -EINVAL;
-       else
-               r = 0;
+
+       if (!target_type || start != 0 || next)
+               goto out;
+
+       if (target && strcmp(target_type, target))
+               goto out;
+
+       /* for target == NULL check all supported */
+       if (!target && (strcmp(target_type, DM_CRYPT_TARGET) &&
+                       strcmp(target_type, DM_VERITY_TARGET)))
+               goto out;
+       r = 0;
 out:
        if (!r && status_line && !(*status_line = strdup(params)))
                r = -ENOMEM;
@@ -641,31 +692,45 @@ out:
        return r;
 }
 
-int dm_status_device(const char *name)
+int dm_status_device(struct crypt_device *cd, const char *name)
 {
        int r;
        struct dm_info dmi;
+       struct stat st;
 
-       r = dm_status_dmi(name, &dmi, DM_CRYPT_TARGET, NULL);
+       /* libdevmapper is too clever and handles
+        * path argument differenly with error.
+        * Fail early here if parameter is non-existent path.
+        */
+       if (strchr(name, '/') && stat(name, &st) < 0)
+               return -ENODEV;
+
+       if (dm_init_context(cd))
+               return -ENOTSUP;
+       r = dm_status_dmi(name, &dmi, NULL, NULL);
+       dm_exit_context();
        if (r < 0)
                return r;
 
        return (dmi.open_count > 0);
 }
 
-int dm_status_suspended(const char *name)
+int dm_status_suspended(struct crypt_device *cd, const char *name)
 {
        int r;
        struct dm_info dmi;
 
+       if (dm_init_context(cd))
+               return -ENOTSUP;
        r = dm_status_dmi(name, &dmi, DM_CRYPT_TARGET, NULL);
+       dm_exit_context();
        if (r < 0)
                return r;
 
        return dmi.suspended ? 1 : 0;
 }
 
-int dm_status_verity_ok(const char *name)
+static int _dm_status_verity_ok(const char *name)
 {
        int r;
        struct dm_info dmi;
@@ -684,6 +749,18 @@ int dm_status_verity_ok(const char *name)
        return r;
 }
 
+int dm_status_verity_ok(struct crypt_device *cd, const char *name)
+{
+       int r;
+
+       if (dm_init_context(cd))
+               return -ENOTSUP;
+       r = _dm_status_verity_ok(name);
+       dm_exit_context();
+       return r;
+}
+
+/* FIXME use hex wrapper, user val wrappers for line parsing */
 static int _dm_query_crypt(uint32_t get_flags,
                           struct dm_info *dmi,
                           char *params,
@@ -692,12 +769,14 @@ static int _dm_query_crypt(uint32_t get_flags,
        uint64_t val64;
        char *rcipher, *key_, *rdevice, *endp, buffer[3], *arg;
        unsigned int i;
+       int r;
 
+       memset(dmd, 0, sizeof(*dmd));
        dmd->target = DM_CRYPT;
 
        rcipher = strsep(&params, " ");
        /* cipher */
-       if (get_flags & DM_ACTIVE_CIPHER)
+       if (get_flags & DM_ACTIVE_CRYPT_CIPHER)
                dmd->u.crypt.cipher = strdup(rcipher);
 
        /* skip */
@@ -713,8 +792,13 @@ static int _dm_query_crypt(uint32_t get_flags,
 
        /* device */
        rdevice = strsep(&params, " ");
-       if (get_flags & DM_ACTIVE_DEVICE)
-               dmd->u.crypt.device = crypt_lookup_dev(rdevice);
+       if (get_flags & DM_ACTIVE_DEVICE) {
+               arg = crypt_lookup_dev(rdevice);
+               r = device_alloc(&dmd->data_device, arg);
+               free(arg);
+               if (r < 0 && r != -ENOTBLK)
+                       return r;
+       }
 
        /*offset */
        if (!params)
@@ -750,17 +834,17 @@ static int _dm_query_crypt(uint32_t get_flags,
        }
 
        /* Never allow to return empty key */
-       if ((get_flags & DM_ACTIVE_KEY) && dmi->suspended) {
+       if ((get_flags & DM_ACTIVE_CRYPT_KEY) && dmi->suspended) {
                log_dbg("Cannot read volume key while suspended.");
                return -EINVAL;
        }
 
-       if (get_flags & DM_ACTIVE_KEYSIZE) {
+       if (get_flags & DM_ACTIVE_CRYPT_KEYSIZE) {
                dmd->u.crypt.vk = crypt_alloc_volume_key(strlen(key_) / 2, NULL);
                if (!dmd->u.crypt.vk)
                        return -ENOMEM;
 
-               if (get_flags & DM_ACTIVE_KEY) {
+               if (get_flags & DM_ACTIVE_CRYPT_KEY) {
                        buffer[2] = '\0';
                        for(i = 0; i < dmd->u.crypt.vk->keylength; i++) {
                                memcpy(buffer, &key_[i * 2], 2);
@@ -783,12 +867,126 @@ static int _dm_query_verity(uint32_t get_flags,
                             char *params,
                             struct crypt_dm_active_device *dmd)
 {
+       struct crypt_params_verity *vp = NULL;
+       uint32_t val32;
+       uint64_t val64;
+       ssize_t len;
+       char *str, *str2;
+       int r;
+
+       if (get_flags & DM_ACTIVE_VERITY_PARAMS)
+               vp = dmd->u.verity.vp;
+
+       memset(dmd, 0, sizeof(*dmd));
+
        dmd->target = DM_VERITY;
-       return -EINVAL;
+       dmd->u.verity.vp = vp;
+
+       /* version */
+       val32 = strtoul(params, &params, 10);
+       if (*params != ' ')
+               return -EINVAL;
+       if (vp)
+               vp->hash_type = val32;
+       params++;
+
+       /* data device */
+       str = strsep(&params, " ");
+       if (!params)
+               return -EINVAL;
+       if (get_flags & DM_ACTIVE_DEVICE) {
+               str2 = crypt_lookup_dev(str);
+               r = device_alloc(&dmd->data_device, str2);
+               free(str2);
+               if (r < 0 && r != -ENOTBLK)
+                       return r;
+       }
+
+       /* hash device */
+       str = strsep(&params, " ");
+       if (!params)
+               return -EINVAL;
+       if (get_flags & DM_ACTIVE_VERITY_HASH_DEVICE) {
+               str2 = crypt_lookup_dev(str);
+               r = device_alloc(&dmd->u.verity.hash_device, str2);
+               free(str2);
+               if (r < 0 && r != -ENOTBLK)
+                       return r;
+       }
+
+       /* data block size*/
+       val32 = strtoul(params, &params, 10);
+       if (*params != ' ')
+               return -EINVAL;
+       if (vp)
+               vp->data_block_size = val32;
+       params++;
+
+       /* hash block size */
+       val32 = strtoul(params, &params, 10);
+       if (*params != ' ')
+               return -EINVAL;
+       if (vp)
+               vp->hash_block_size = val32;
+       params++;
+
+       /* data blocks */
+       val64 = strtoull(params, &params, 10);
+       if (*params != ' ')
+               return -EINVAL;
+       if (vp)
+               vp->data_size = val64;
+       params++;
+
+       /* hash start */
+       val64 = strtoull(params, &params, 10);
+       if (*params != ' ')
+               return -EINVAL;
+       dmd->u.verity.hash_offset = val64;
+       params++;
+
+       /* hash algorithm */
+       str = strsep(&params, " ");
+       if (!params)
+               return -EINVAL;
+       if (vp)
+               vp->hash_name = strdup(str);
+
+       /* root digest */
+       str = strsep(&params, " ");
+       if (!params)
+               return -EINVAL;
+       len = crypt_hex_to_bytes(str, &str2, 0);
+       if (len < 0)
+               return len;
+       dmd->u.verity.root_hash_size = len;
+       if (get_flags & DM_ACTIVE_VERITY_ROOT_HASH)
+               dmd->u.verity.root_hash = str2;
+       else
+               free(str2);
+
+       /* salt */
+       str = strsep(&params, " ");
+       if (params)
+               return -EINVAL;
+       if (vp) {
+               if (!strcmp(str, "-")) {
+                       vp->salt_size = 0;
+                       vp->salt = NULL;
+               } else {
+                       len = crypt_hex_to_bytes(str, &str2, 0);
+                       if (len < 0)
+                               return len;
+                       vp->salt_size = len;
+                       vp->salt = str2;
+               }
+       }
+
+       return 0;
 }
 
-int dm_query_device(const char *name, uint32_t get_flags,
-                   struct crypt_dm_active_device *dmd)
+int dm_query_device(struct crypt_device *cd, const char *name,
+                   uint32_t get_flags, struct crypt_dm_active_device *dmd)
 {
        struct dm_task *dmt;
        struct dm_info dmi;
@@ -798,8 +996,8 @@ int dm_query_device(const char *name, uint32_t get_flags,
        void *next = NULL;
        int r = -EINVAL;
 
-       memset(dmd, 0, sizeof(*dmd));
-
+       if (dm_init_context(cd))
+               return -ENOTSUP;
        if (!(dmt = dm_task_create(DM_DEVICE_TABLE)))
                goto out;
        if ((dm_flags() & DM_SECURE_SUPPORTED) && !dm_task_secure_data(dmt))
@@ -825,11 +1023,19 @@ int dm_query_device(const char *name, uint32_t get_flags,
        if (!target_type || start != 0 || next)
                goto out;
 
-       if (!strcmp(target_type, DM_CRYPT_TARGET))
+       if (!strcmp(target_type, DM_CRYPT_TARGET)) {
                r = _dm_query_crypt(get_flags, &dmi, params, dmd);
-       else if (!strcmp(target_type, DM_VERITY_TARGET))
+       } else if (!strcmp(target_type, DM_VERITY_TARGET)) {
                r = _dm_query_verity(get_flags, &dmi, params, dmd);
-       else
+               if (r < 0)
+                       goto out;
+               r = _dm_status_verity_ok(name);
+               if (r < 0)
+                       goto out;
+               if (r == 0)
+                       dmd->flags |= CRYPT_ACTIVATE_CORRUPTED;
+               r = 0;
+       } else
                r = -EINVAL;
 
        if (r < 0)
@@ -853,6 +1059,7 @@ out:
        if (dmt)
                dm_task_destroy(dmt);
 
+       dm_exit_context();
        return r;
 }
 
@@ -883,52 +1090,63 @@ static int _dm_message(const char *name, const char *msg)
        return r;
 }
 
-int dm_suspend_and_wipe_key(const char *name)
+int dm_suspend_and_wipe_key(struct crypt_device *cd, const char *name)
 {
-       if (!_dm_check_versions())
+       int r = -ENOTSUP;
+
+       if (dm_init_context(cd))
                return -ENOTSUP;
 
        if (!(_dm_crypt_flags & DM_KEY_WIPE_SUPPORTED))
-               return -ENOTSUP;
+               goto out;
 
-       if (!_dm_simple(DM_DEVICE_SUSPEND, name, 0))
-               return -EINVAL;
+       if (!_dm_simple(DM_DEVICE_SUSPEND, name, 0)) {
+               r = -EINVAL;
+               goto out;
+       }
 
        if (!_dm_message(name, "key wipe")) {
                _dm_simple(DM_DEVICE_RESUME, name, 1);
-               return -EINVAL;
+               r = -EINVAL;
+               goto out;
        }
-
-       return 0;
+       r = 0;
+out:
+       dm_exit_context();
+       return r;
 }
 
-int dm_resume_and_reinstate_key(const char *name,
-                               size_t key_size,
-                               const char *key)
+int dm_resume_and_reinstate_key(struct crypt_device *cd, const char *name,
+                               size_t key_size, const char *key)
 {
        int msg_size = key_size * 2 + 10; // key set <key>
-       char *msg;
-       int r = 0;
+       char *msg = NULL;
+       int r = -ENOTSUP;
 
-       if (!_dm_check_versions())
+       if (dm_init_context(cd))
                return -ENOTSUP;
 
        if (!(_dm_crypt_flags & DM_KEY_WIPE_SUPPORTED))
-               return -ENOTSUP;
+               goto out;
 
        msg = crypt_safe_alloc(msg_size);
-       if (!msg)
-               return -ENOMEM;
+       if (!msg) {
+               r = -ENOMEM;
+               goto out;
+       }
 
-       memset(msg, 0, msg_size);
        strcpy(msg, "key set ");
        hex_key(&msg[8], key_size, key);
 
        if (!_dm_message(name, msg) ||
-           !_dm_simple(DM_DEVICE_RESUME, name, 1))
+           !_dm_simple(DM_DEVICE_RESUME, name, 1)) {
                r = -EINVAL;
-
+               goto out;
+       }
+       r = 0;
+out:
        crypt_safe_free(msg);
+       dm_exit_context();
        return r;
 }
 
@@ -946,27 +1164,3 @@ int dm_is_dm_kernel_name(const char *name)
 {
        return strncmp(name, "dm-", 3) ? 0 : 1;
 }
-
-int dm_check_segment(const char *name, uint64_t offset, uint64_t size)
-{
-       struct crypt_dm_active_device dmd;
-       int r;
-
-       log_dbg("Checking segments for device %s.", name);
-
-       r = dm_query_device(name, 0, &dmd);
-       if (r < 0)
-               return r;
-
-       if (offset >= (dmd.u.crypt.offset + dmd.size) ||
-          (offset + size) <= dmd.u.crypt.offset)
-               r = 0;
-       else
-               r = -EBUSY;
-
-       log_dbg("seg: %" PRIu64 " - %" PRIu64 ", new %" PRIu64 " - %" PRIu64 "%s",
-              dmd.u.crypt.offset, dmd.u.crypt.offset + dmd.size, offset, offset + size,
-              r ? " (overlapping)" : " (ok)");
-
-       return r;
-}