src/shared/cryptsetup-util.c

   1 /* SPDX-License-Identifier: LGPL-2.1-or-later */
   2
   3 #include "alloc-util.h"
   4 #include "cryptsetup-util.h"
   5 #include "dlfcn-util.h"
   6 #include "log.h"
   7 #include "parse-util.h"
   8
   9 #if HAVE_LIBCRYPTSETUP
  10 static void *cryptsetup_dl = NULL;
  11
  12 int (*sym_crypt_activate_by_passphrase)(struct crypt_device *cd, const char *name, int keyslot, const char *passphrase, size_t passphrase_size, uint32_t flags);
  13 #if HAVE_CRYPT_ACTIVATE_BY_SIGNED_KEY
  14 int (*sym_crypt_activate_by_signed_key)(struct crypt_device *cd, const char *name, const char *volume_key, size_t volume_key_size, const char *signature, size_t signature_size, uint32_t flags);
  15 #endif
  16 int (*sym_crypt_activate_by_volume_key)(struct crypt_device *cd, const char *name, const char *volume_key, size_t volume_key_size, uint32_t flags);
  17 int (*sym_crypt_deactivate_by_name)(struct crypt_device *cd, const char *name, uint32_t flags);
  18 int (*sym_crypt_format)(struct crypt_device *cd, const char *type, const char *cipher, const char *cipher_mode, const char *uuid, const char *volume_key, size_t volume_key_size, void *params);
  19 void (*sym_crypt_free)(struct crypt_device *cd);
  20 const char *(*sym_crypt_get_cipher)(struct crypt_device *cd);
  21 const char *(*sym_crypt_get_cipher_mode)(struct crypt_device *cd);
  22 uint64_t (*sym_crypt_get_data_offset)(struct crypt_device *cd);
  23 const char *(*sym_crypt_get_device_name)(struct crypt_device *cd);
  24 const char *(*sym_crypt_get_dir)(void);
  25 const char *(*sym_crypt_get_type)(struct crypt_device *cd);
  26 const char *(*sym_crypt_get_uuid)(struct crypt_device *cd);
  27 int (*sym_crypt_get_verity_info)(struct crypt_device *cd, struct crypt_params_verity *vp);
  28 int (*sym_crypt_get_volume_key_size)(struct crypt_device *cd);
  29 int (*sym_crypt_init)(struct crypt_device **cd, const char *device);
  30 int (*sym_crypt_init_by_name)(struct crypt_device **cd, const char *name);
  31 int (*sym_crypt_keyslot_add_by_volume_key)(struct crypt_device *cd, int keyslot, const char *volume_key, size_t volume_key_size, const char *passphrase, size_t passphrase_size);
  32 int (*sym_crypt_keyslot_destroy)(struct crypt_device *cd, int keyslot);
  33 int (*sym_crypt_keyslot_max)(const char *type);
  34 int (*sym_crypt_load)(struct crypt_device *cd, const char *requested_type, void *params);
  35 int (*sym_crypt_resize)(struct crypt_device *cd, const char *name, uint64_t new_size);
  36 int (*sym_crypt_resume_by_passphrase)(struct crypt_device *cd, const char *name, int keyslot, const char *passphrase, size_t passphrase_size);
  37 int (*sym_crypt_set_data_device)(struct crypt_device *cd, const char *device);
  38 void (*sym_crypt_set_debug_level)(int level);
  39 void (*sym_crypt_set_log_callback)(struct crypt_device *cd, void (*log)(int level, const char *msg, void *usrptr), void *usrptr);
  40 #if HAVE_CRYPT_SET_METADATA_SIZE
  41 int (*sym_crypt_set_metadata_size)(struct crypt_device *cd, uint64_t metadata_size, uint64_t keyslots_size);
  42 #endif
  43 int (*sym_crypt_set_pbkdf_type)(struct crypt_device *cd, const struct crypt_pbkdf_type *pbkdf);
  44 int (*sym_crypt_suspend)(struct crypt_device *cd, const char *name);
  45 int (*sym_crypt_token_json_get)(struct crypt_device *cd, int token, const char **json);
  46 int (*sym_crypt_token_json_set)(struct crypt_device *cd, int token, const char *json);
  47 #if HAVE_CRYPT_TOKEN_MAX
  48 int (*sym_crypt_token_max)(const char *type);
  49 #endif
  50 crypt_token_info (*sym_crypt_token_status)(struct crypt_device *cd, int token, const char **type);
  51 int (*sym_crypt_volume_key_get)(struct crypt_device *cd, int keyslot, char *volume_key, size_t *volume_key_size, const char *passphrase, size_t passphrase_size);
  52 #if HAVE_CRYPT_REENCRYPT_INIT_BY_PASSPHRASE
  53 int (*sym_crypt_reencrypt_init_by_passphrase)(struct crypt_device *cd, const char *name, const char *passphrase, size_t passphrase_size, int keyslot_old, int keyslot_new, const char *cipher, const char *cipher_mode, const struct crypt_params_reencrypt *params);
  54 #endif
  55 #if HAVE_CRYPT_REENCRYPT
  56 int (*sym_crypt_reencrypt)(struct crypt_device *cd, int (*progress)(uint64_t size, uint64_t offset, void *usrptr));
  57 #endif
  58 int (*sym_crypt_metadata_locking)(struct crypt_device *cd, int enable);
  59 #if HAVE_CRYPT_SET_DATA_OFFSET
  60 int (*sym_crypt_set_data_offset)(struct crypt_device *cd, uint64_t data_offset);
  61 #endif
  62 int (*sym_crypt_header_restore)(struct crypt_device *cd, const char *requested_type, const char *backup_file);
  63 int (*sym_crypt_volume_key_keyring)(struct crypt_device *cd, int enable);
  64
  65 /* Unfortunately libcryptsetup provides neither an environment variable to redirect where to look for token
  66  * modules, nor does it have an API to change the token lookup path at runtime. The maintainers suggest using
  67  * ELF interposition instead (see https://gitlab.com/cryptsetup/cryptsetup/-/issues/846). Hence let's do
  68  * that: let's interpose libcryptsetup's crypt_token_external_path() function with our own, that *does*
  69  * honour an environment variable where to look for tokens. This is tremendously useful for debugging
  70  * libcryptsetup tokens: set the environment variable to your build dir and you can easily test token modules
  71  * without jumping through various hoops. */
  72
  73 /* Do this only on new enough compilers that actually support the "symver" attribute. Given this is a debug
  74  * feature, let's simply not bother on older compilers */
  75 #if defined __has_attribute
  76 #if __has_attribute(symver)
  77 const char *my_crypt_token_external_path(void); /* prototype for our own implementation */
  78
  79 /* We use the "symver" attribute to mark this implementation as the default implementation, and drop the
  80  * SD_SHARED namespace we by default attach to our symbols via a version script. */
  81 __attribute__((symver("crypt_token_external_path@@")))
  82 _public_ const char *my_crypt_token_external_path(void) {
  83         const char *e;
  84
  85         e = secure_getenv("SYSTEMD_CRYPTSETUP_TOKEN_PATH");
  86         if (e)
  87                 return e;
  88
  89         /* Now chain invoke the original implementation. */
  90         if (cryptsetup_dl) {
  91                 typeof(crypt_token_external_path) *func;
  92                 func = (typeof(crypt_token_external_path)*) dlsym(cryptsetup_dl, "crypt_token_external_path");
  93                 if (func)
  94                         return func();
  95         }
  96
  97         return NULL;
  98 }
  99 #endif
 100 #endif
 101
 102 static void cryptsetup_log_glue(int level, const char *msg, void *usrptr) {
 103
 104         switch (level) {
 105         case CRYPT_LOG_NORMAL:
 106                 level = LOG_NOTICE;
 107                 break;
 108         case CRYPT_LOG_ERROR:
 109                 level = LOG_ERR;
 110                 break;
 111         case CRYPT_LOG_VERBOSE:
 112                 level = LOG_INFO;
 113                 break;
 114         case CRYPT_LOG_DEBUG:
 115                 level = LOG_DEBUG;
 116                 break;
 117         default:
 118                 log_error("Unknown libcryptsetup log level: %d", level);
 119                 level = LOG_ERR;
 120         }
 121
 122         log_full(level, "%s", msg);
 123 }
 124
 125 void cryptsetup_enable_logging(struct crypt_device *cd) {
 126         /* It's OK to call this with a NULL parameter, in which case libcryptsetup will set the default log
 127          * function.
 128          *
 129          * Note that this is also called from dlopen_cryptsetup(), which we call here too. Sounds like an
 130          * endless loop, but isn't because we break it via the check for 'cryptsetup_dl' early in
 131          * dlopen_cryptsetup(). */
 132
 133         if (dlopen_cryptsetup() < 0)
 134                 return; /* If this fails, let's gracefully ignore the issue, this is just debug logging after
 135                          * all, and if this failed we already generated a debug log message that should help
 136                          * to track things down. */
 137
 138         sym_crypt_set_log_callback(cd, cryptsetup_log_glue, NULL);
 139         sym_crypt_set_debug_level(DEBUG_LOGGING ? CRYPT_DEBUG_ALL : CRYPT_DEBUG_NONE);
 140 }
 141
 142 int cryptsetup_set_minimal_pbkdf(struct crypt_device *cd) {
 143
 144         /* With CRYPT_PBKDF_NO_BENCHMARK flag set .time_ms member is ignored
 145          * while .iterations must be set at least to recommended minimum value. */
 146
 147         static const struct crypt_pbkdf_type minimal_pbkdf = {
 148                 .hash = "sha512",
 149                 .type = CRYPT_KDF_PBKDF2,
 150                 .iterations = 1000, /* recommended minimum count for pbkdf2
 151                                      * according to NIST SP 800-132, ch. 5.2 */
 152                 .flags = CRYPT_PBKDF_NO_BENCHMARK
 153         };
 154
 155         int r;
 156
 157         /* Sets a minimal PKBDF in case we already have a high entropy key. */
 158
 159         r = dlopen_cryptsetup();
 160         if (r < 0)
 161                 return r;
 162
 163         r = sym_crypt_set_pbkdf_type(cd, &minimal_pbkdf);
 164         if (r < 0)
 165                 return r;
 166
 167         return 0;
 168 }
 169
 170 int cryptsetup_get_token_as_json(
 171                 struct crypt_device *cd,
 172                 int idx,
 173                 const char *verify_type,
 174                 JsonVariant **ret) {
 175
 176         _cleanup_(json_variant_unrefp) JsonVariant *v = NULL;
 177         const char *text;
 178         int r;
 179
 180         assert(cd);
 181
 182         /* Extracts and parses the LUKS2 JSON token data from a LUKS2 device. Optionally verifies the type of
 183          * the token. Returns:
 184          *
 185          *      -EINVAL → token index out of range or "type" field missing
 186          *      -ENOENT → token doesn't exist
 187          * -EMEDIUMTYPE → "verify_type" specified and doesn't match token's type
 188          */
 189
 190         r = dlopen_cryptsetup();
 191         if (r < 0)
 192                 return r;
 193
 194         r = sym_crypt_token_json_get(cd, idx, &text);
 195         if (r < 0)
 196                 return r;
 197
 198         r = json_parse(text, 0, &v, NULL, NULL);
 199         if (r < 0)
 200                 return r;
 201
 202         if (verify_type) {
 203                 JsonVariant *w;
 204
 205                 w = json_variant_by_key(v, "type");
 206                 if (!w)
 207                         return -EINVAL;
 208
 209                 if (!streq_ptr(json_variant_string(w), verify_type))
 210                         return -EMEDIUMTYPE;
 211         }
 212
 213         if (ret)
 214                 *ret = TAKE_PTR(v);
 215
 216         return 0;
 217 }
 218
 219 int cryptsetup_add_token_json(struct crypt_device *cd, JsonVariant *v) {
 220         _cleanup_free_ char *text = NULL;
 221         int r;
 222
 223         r = dlopen_cryptsetup();
 224         if (r < 0)
 225                 return r;
 226
 227         r = json_variant_format(v, 0, &text);
 228         if (r < 0)
 229                 return log_debug_errno(r, "Failed to format token data for LUKS: %m");
 230
 231         log_debug("Adding token text <%s>", text);
 232
 233         r = sym_crypt_token_json_set(cd, CRYPT_ANY_TOKEN, text);
 234         if (r < 0)
 235                 return log_debug_errno(r, "Failed to write token data to LUKS: %m");
 236
 237         return 0;
 238 }
 239 #endif
 240
 241 int dlopen_cryptsetup(void) {
 242 #if HAVE_LIBCRYPTSETUP
 243         int r;
 244
 245         /* libcryptsetup added crypt_reencrypt() in 2.2.0, and marked it obsolete in 2.4.0, replacing it with
 246          * crypt_reencrypt_run(), which takes one extra argument but is otherwise identical. The old call is
 247          * still available though, and given we want to support 2.2.0 for a while longer, we'll stick to the
 248          * old symbol. However, the old symbols now has a GCC deprecation decorator, hence let's turn off
 249          * warnings about this for now. */
 250
 251         DISABLE_WARNING_DEPRECATED_DECLARATIONS;
 252
 253         r = dlopen_many_sym_or_warn(
 254                         &cryptsetup_dl, "libcryptsetup.so.12", LOG_DEBUG,
 255                         DLSYM_ARG(crypt_activate_by_passphrase),
 256 #if HAVE_CRYPT_ACTIVATE_BY_SIGNED_KEY
 257                         DLSYM_ARG(crypt_activate_by_signed_key),
 258 #endif
 259                         DLSYM_ARG(crypt_activate_by_volume_key),
 260                         DLSYM_ARG(crypt_deactivate_by_name),
 261                         DLSYM_ARG(crypt_format),
 262                         DLSYM_ARG(crypt_free),
 263                         DLSYM_ARG(crypt_get_cipher),
 264                         DLSYM_ARG(crypt_get_cipher_mode),
 265                         DLSYM_ARG(crypt_get_data_offset),
 266                         DLSYM_ARG(crypt_get_device_name),
 267                         DLSYM_ARG(crypt_get_dir),
 268                         DLSYM_ARG(crypt_get_type),
 269                         DLSYM_ARG(crypt_get_uuid),
 270                         DLSYM_ARG(crypt_get_verity_info),
 271                         DLSYM_ARG(crypt_get_volume_key_size),
 272                         DLSYM_ARG(crypt_init),
 273                         DLSYM_ARG(crypt_init_by_name),
 274                         DLSYM_ARG(crypt_keyslot_add_by_volume_key),
 275                         DLSYM_ARG(crypt_keyslot_destroy),
 276                         DLSYM_ARG(crypt_keyslot_max),
 277                         DLSYM_ARG(crypt_load),
 278                         DLSYM_ARG(crypt_resize),
 279                         DLSYM_ARG(crypt_resume_by_passphrase),
 280                         DLSYM_ARG(crypt_set_data_device),
 281                         DLSYM_ARG(crypt_set_debug_level),
 282                         DLSYM_ARG(crypt_set_log_callback),
 283 #if HAVE_CRYPT_SET_METADATA_SIZE
 284                         DLSYM_ARG(crypt_set_metadata_size),
 285 #endif
 286                         DLSYM_ARG(crypt_set_pbkdf_type),
 287                         DLSYM_ARG(crypt_suspend),
 288                         DLSYM_ARG(crypt_token_json_get),
 289                         DLSYM_ARG(crypt_token_json_set),
 290 #if HAVE_CRYPT_TOKEN_MAX
 291                         DLSYM_ARG(crypt_token_max),
 292 #endif
 293                         DLSYM_ARG(crypt_token_status),
 294                         DLSYM_ARG(crypt_volume_key_get),
 295 #if HAVE_CRYPT_REENCRYPT_INIT_BY_PASSPHRASE
 296                         DLSYM_ARG(crypt_reencrypt_init_by_passphrase),
 297 #endif
 298 #if HAVE_CRYPT_REENCRYPT
 299                         DLSYM_ARG(crypt_reencrypt),
 300 #endif
 301                         DLSYM_ARG(crypt_metadata_locking),
 302 #if HAVE_CRYPT_SET_DATA_OFFSET
 303                         DLSYM_ARG(crypt_set_data_offset),
 304 #endif
 305                         DLSYM_ARG(crypt_header_restore),
 306                         DLSYM_ARG(crypt_volume_key_keyring));
 307         if (r <= 0)
 308                 return r;
 309
 310         REENABLE_WARNING;
 311
 312         /* Redirect the default logging calls of libcryptsetup to our own logging infra. (Note that
 313          * libcryptsetup also maintains per-"struct crypt_device" log functions, which we'll also set
 314          * whenever allocating a "struct crypt_device" context. Why set both? To be defensive: maybe some
 315          * other code loaded into this process also changes the global log functions of libcryptsetup, who
 316          * knows? And if so, we still want our own objects to log via our own infra, at the very least.) */
 317         cryptsetup_enable_logging(NULL);
 318         return 1;
 319 #else
 320         return log_error_errno(SYNTHETIC_ERRNO(EOPNOTSUPP), "cryptsetup support is not compiled in.");
 321 #endif
 322 }
 323
 324 int cryptsetup_get_keyslot_from_token(JsonVariant *v) {
 325         int keyslot, r;
 326         JsonVariant *w;
 327
 328         /* Parses the "keyslots" field of a LUKS2 token object. The field can be an array, but here we assume
 329          * that it contains a single element only, since that's the only way we ever generate it
 330          * ourselves. */
 331
 332         w = json_variant_by_key(v, "keyslots");
 333         if (!w)
 334                 return -ENOENT;
 335         if (!json_variant_is_array(w) || json_variant_elements(w) != 1)
 336                 return -EMEDIUMTYPE;
 337
 338         w = json_variant_by_index(w, 0);
 339         if (!w)
 340                 return -ENOENT;
 341         if (!json_variant_is_string(w))
 342                 return -EMEDIUMTYPE;
 343
 344         r = safe_atoi(json_variant_string(w), &keyslot);
 345         if (r < 0)
 346                 return r;
 347         if (keyslot < 0)
 348                 return -EINVAL;
 349
 350         return keyslot;
 351 }