src/dissect/dissect.c

   1 /* SPDX-License-Identifier: LGPL-2.1+ */
   2
   3 #include <fcntl.h>
   4 #include <getopt.h>
   5 #include <linux/loop.h>
   6 #include <stdio.h>
   7
   8 #include "architecture.h"
   9 #include "dissect-image.h"
  10 #include "hexdecoct.h"
  11 #include "log.h"
  12 #include "loop-util.h"
  13 #include "main-func.h"
  14 #include "parse-util.h"
  15 #include "path-util.h"
  16 #include "string-util.h"
  17 #include "strv.h"
  18 #include "user-util.h"
  19 #include "util.h"
  20
  21 static enum {
  22         ACTION_DISSECT,
  23         ACTION_MOUNT,
  24 } arg_action = ACTION_DISSECT;
  25 static const char *arg_image = NULL;
  26 static const char *arg_path = NULL;
  27 static DissectImageFlags arg_flags = DISSECT_IMAGE_REQUIRE_ROOT|DISSECT_IMAGE_DISCARD_ON_LOOP|DISSECT_IMAGE_RELAX_VAR_CHECK|DISSECT_IMAGE_FSCK;
  28 static void *arg_root_hash = NULL;
  29 static char *arg_verity_data = NULL;
  30 static size_t arg_root_hash_size = 0;
  31 static char *arg_root_hash_sig_path = NULL;
  32 static void *arg_root_hash_sig = NULL;
  33 static size_t arg_root_hash_sig_size = 0;
  34
  35 STATIC_DESTRUCTOR_REGISTER(arg_root_hash, freep);
  36 STATIC_DESTRUCTOR_REGISTER(arg_verity_data, freep);
  37 STATIC_DESTRUCTOR_REGISTER(arg_root_hash_sig_path, freep);
  38 STATIC_DESTRUCTOR_REGISTER(arg_root_hash_sig, freep);
  39
  40 static void help(void) {
  41         printf("%s [OPTIONS...] IMAGE\n"
  42                "%s [OPTIONS...] --mount IMAGE PATH\n"
  43                "Dissect a file system OS image.\n\n"
  44                "  -h --help               Show this help\n"
  45                "     --version            Show package version\n"
  46                "  -m --mount              Mount the image to the specified directory\n"
  47                "  -r --read-only          Mount read-only\n"
  48                "     --fsck=BOOL          Run fsck before mounting\n"
  49                "     --discard=MODE       Choose 'discard' mode (disabled, loop, all, crypto)\n"
  50                "     --root-hash=HASH     Specify root hash for verity\n"
  51                "     --root-hash-sig=SIG  Specify pkcs7 signature of root hash for verity\n"
  52                "                          as a DER encoded PKCS7, either as a path to a file\n"
  53                "                          or as an ASCII base64 encoded string prefixed by\n"
  54                "                          'base64:'\n"
  55                "     --verity-data=PATH   Specify data file with hash tree for verity if it is\n"
  56                "                          not embedded in IMAGE\n",
  57                program_invocation_short_name,
  58                program_invocation_short_name);
  59 }
  60
  61 static int parse_argv(int argc, char *argv[]) {
  62
  63         enum {
  64                 ARG_VERSION = 0x100,
  65                 ARG_DISCARD,
  66                 ARG_ROOT_HASH,
  67                 ARG_FSCK,
  68                 ARG_VERITY_DATA,
  69                 ARG_ROOT_HASH_SIG,
  70         };
  71
  72         static const struct option options[] = {
  73                 { "help",          no_argument,       NULL, 'h'               },
  74                 { "version",       no_argument,       NULL, ARG_VERSION       },
  75                 { "mount",         no_argument,       NULL, 'm'               },
  76                 { "read-only",     no_argument,       NULL, 'r'               },
  77                 { "discard",       required_argument, NULL, ARG_DISCARD       },
  78                 { "root-hash",     required_argument, NULL, ARG_ROOT_HASH     },
  79                 { "fsck",          required_argument, NULL, ARG_FSCK          },
  80                 { "verity-data",   required_argument, NULL, ARG_VERITY_DATA   },
  81                 { "root-hash-sig", required_argument, NULL, ARG_ROOT_HASH_SIG },
  82                 {}
  83         };
  84
  85         int c, r;
  86
  87         assert(argc >= 0);
  88         assert(argv);
  89
  90         while ((c = getopt_long(argc, argv, "hmr", options, NULL)) >= 0) {
  91
  92                 switch (c) {
  93
  94                 case 'h':
  95                         help();
  96                         return 0;
  97
  98                 case ARG_VERSION:
  99                         return version();
 100
 101                 case 'm':
 102                         arg_action = ACTION_MOUNT;
 103                         break;
 104
 105                 case 'r':
 106                         arg_flags |= DISSECT_IMAGE_READ_ONLY;
 107                         break;
 108
 109                 case ARG_DISCARD: {
 110                         DissectImageFlags flags;
 111
 112                         if (streq(optarg, "disabled"))
 113                                 flags = 0;
 114                         else if (streq(optarg, "loop"))
 115                                 flags = DISSECT_IMAGE_DISCARD_ON_LOOP;
 116                         else if (streq(optarg, "all"))
 117                                 flags = DISSECT_IMAGE_DISCARD_ON_LOOP | DISSECT_IMAGE_DISCARD;
 118                         else if (streq(optarg, "crypt"))
 119                                 flags = DISSECT_IMAGE_DISCARD_ANY;
 120                         else
 121                                 return log_error_errno(SYNTHETIC_ERRNO(EINVAL),
 122                                                        "Unknown --discard= parameter: %s",
 123                                                        optarg);
 124                         arg_flags = (arg_flags & ~DISSECT_IMAGE_DISCARD_ANY) | flags;
 125
 126                         break;
 127                 }
 128
 129                 case ARG_ROOT_HASH: {
 130                         void *p;
 131                         size_t l;
 132
 133                         r = unhexmem(optarg, strlen(optarg), &p, &l);
 134                         if (r < 0)
 135                                 return log_error_errno(r, "Failed to parse root hash '%s': %m", optarg);
 136                         if (l < sizeof(sd_id128_t)) {
 137                                 log_error("Root hash must be at least 128bit long: %s", optarg);
 138                                 free(p);
 139                                 return -EINVAL;
 140                         }
 141
 142                         free(arg_root_hash);
 143                         arg_root_hash = p;
 144                         arg_root_hash_size = l;
 145                         break;
 146                 }
 147
 148                 case ARG_VERITY_DATA:
 149                         r = parse_path_argument_and_warn(optarg, false, &arg_verity_data);
 150                         if (r < 0)
 151                                 return r;
 152                         break;
 153
 154                 case ARG_ROOT_HASH_SIG: {
 155                         char *value;
 156
 157                         if ((value = startswith(optarg, "base64:"))) {
 158                                 void *p;
 159                                 size_t l;
 160
 161                                 r = unbase64mem(value, strlen(value), &p, &l);
 162                                 if (r < 0)
 163                                         return log_error_errno(r, "Failed to parse root hash signature '%s': %m", optarg);
 164
 165                                 free_and_replace(arg_root_hash_sig, p);
 166                                 arg_root_hash_sig_size = l;
 167                                 arg_root_hash_sig_path = mfree(arg_root_hash_sig_path);
 168                         } else {
 169                                 r = parse_path_argument_and_warn(optarg, false, &arg_root_hash_sig_path);
 170                                 if (r < 0)
 171                                         return r;
 172                                 arg_root_hash_sig = mfree(arg_root_hash_sig);
 173                                 arg_root_hash_sig_size = 0;
 174                         }
 175
 176                         break;
 177                 }
 178
 179                 case ARG_FSCK:
 180                         r = parse_boolean(optarg);
 181                         if (r < 0)
 182                                 return log_error_errno(r, "Failed to parse --fsck= parameter: %s", optarg);
 183
 184                         SET_FLAG(arg_flags, DISSECT_IMAGE_FSCK, r);
 185                         break;
 186
 187                 case '?':
 188                         return -EINVAL;
 189
 190                 default:
 191                         assert_not_reached("Unhandled option");
 192                 }
 193
 194         }
 195
 196         switch (arg_action) {
 197
 198         case ACTION_DISSECT:
 199                 if (optind + 1 != argc)
 200                         return log_error_errno(SYNTHETIC_ERRNO(EINVAL),
 201                                                "Expected a file path as only argument.");
 202
 203                 arg_image = argv[optind];
 204                 arg_flags |= DISSECT_IMAGE_READ_ONLY;
 205                 break;
 206
 207         case ACTION_MOUNT:
 208                 if (optind + 2 != argc)
 209                         return log_error_errno(SYNTHETIC_ERRNO(EINVAL),
 210                                                "Expected a file path and mount point path as only arguments.");
 211
 212                 arg_image = argv[optind];
 213                 arg_path = argv[optind + 1];
 214                 break;
 215
 216         default:
 217                 assert_not_reached("Unknown action.");
 218         }
 219
 220         return 1;
 221 }
 222
 223 static int run(int argc, char *argv[]) {
 224         _cleanup_(loop_device_unrefp) LoopDevice *d = NULL;
 225         _cleanup_(decrypted_image_unrefp) DecryptedImage *di = NULL;
 226         _cleanup_(dissected_image_unrefp) DissectedImage *m = NULL;
 227         int r;
 228
 229         log_parse_environment();
 230         log_open();
 231
 232         r = parse_argv(argc, argv);
 233         if (r <= 0)
 234                 return r;
 235
 236         r = loop_device_make_by_path(arg_image, (arg_flags & DISSECT_IMAGE_READ_ONLY) ? O_RDONLY : O_RDWR, LO_FLAGS_PARTSCAN, &d);
 237         if (r < 0)
 238                 return log_error_errno(r, "Failed to set up loopback device: %m");
 239
 240         r = verity_metadata_load(arg_image, NULL, arg_root_hash ? NULL : &arg_root_hash, &arg_root_hash_size,
 241                            arg_verity_data ? NULL : &arg_verity_data,
 242                            arg_root_hash_sig_path || arg_root_hash_sig ? NULL : &arg_root_hash_sig_path);
 243         if (r < 0)
 244                 return log_error_errno(r, "Failed to read verity artefacts for %s: %m", arg_image);
 245         arg_flags |= arg_verity_data ? DISSECT_IMAGE_NO_PARTITION_TABLE : 0;
 246
 247         r = dissect_image_and_warn(d->fd, arg_image, arg_root_hash, arg_root_hash_size, arg_verity_data, NULL, arg_flags, &m);
 248         if (r < 0)
 249                 return r;
 250
 251         switch (arg_action) {
 252
 253         case ACTION_DISSECT: {
 254                 unsigned i;
 255
 256                 for (i = 0; i < _PARTITION_DESIGNATOR_MAX; i++) {
 257                         DissectedPartition *p = m->partitions + i;
 258
 259                         if (!p->found)
 260                                 continue;
 261
 262                         printf("Found %s '%s' partition",
 263                                p->rw ? "writable" : "read-only",
 264                                partition_designator_to_string(i));
 265
 266                         if (!sd_id128_is_null(p->uuid))
 267                                 printf(" (UUID " SD_ID128_FORMAT_STR ")", SD_ID128_FORMAT_VAL(p->uuid));
 268
 269                         if (p->fstype)
 270                                 printf(" of type %s", p->fstype);
 271
 272                         if (p->architecture != _ARCHITECTURE_INVALID)
 273                                 printf(" for %s", architecture_to_string(p->architecture));
 274
 275                         if (dissected_image_can_do_verity(m, i))
 276                                 printf(" %s verity", dissected_image_has_verity(m, i) ? "with" : "without");
 277
 278                         if (p->partno >= 0)
 279                                 printf(" on partition #%i", p->partno);
 280
 281                         if (p->node)
 282                                 printf(" (%s)", p->node);
 283
 284                         putchar('\n');
 285                 }
 286
 287                 r = dissected_image_acquire_metadata(m);
 288                 if (r < 0)
 289                         return log_error_errno(r, "Failed to acquire image metadata: %m");
 290
 291                 if (m->hostname)
 292                         printf("  Hostname: %s\n", m->hostname);
 293
 294                 if (!sd_id128_is_null(m->machine_id))
 295                         printf("Machine ID: " SD_ID128_FORMAT_STR "\n", SD_ID128_FORMAT_VAL(m->machine_id));
 296
 297                 if (!strv_isempty(m->machine_info)) {
 298                         char **p, **q;
 299
 300                         STRV_FOREACH_PAIR(p, q, m->machine_info)
 301                                 printf("%s %s=%s\n",
 302                                        p == m->machine_info ? "Mach. Info:" : "           ",
 303                                        *p, *q);
 304                 }
 305
 306                 if (!strv_isempty(m->os_release)) {
 307                         char **p, **q;
 308
 309                         STRV_FOREACH_PAIR(p, q, m->os_release)
 310                                 printf("%s %s=%s\n",
 311                                        p == m->os_release ? "OS Release:" : "           ",
 312                                        *p, *q);
 313                 }
 314
 315                 break;
 316         }
 317
 318         case ACTION_MOUNT:
 319                 r = dissected_image_decrypt_interactively(m, NULL, arg_root_hash, arg_root_hash_size, arg_verity_data, arg_root_hash_sig_path, arg_root_hash_sig, arg_root_hash_sig_size, arg_flags, &di);
 320                 if (r < 0)
 321                         return r;
 322
 323                 r = dissected_image_mount(m, arg_path, UID_INVALID, arg_flags);
 324                 if (r == -EUCLEAN)
 325                         return log_error_errno(r, "File system check on image failed: %m");
 326                 if (r < 0)
 327                         return log_error_errno(r, "Failed to mount image: %m");
 328
 329                 if (di) {
 330                         r = decrypted_image_relinquish(di);
 331                         if (r < 0)
 332                                 return log_error_errno(r, "Failed to relinquish DM devices: %m");
 333                 }
 334
 335                 loop_device_relinquish(d);
 336                 break;
 337
 338         default:
 339                 assert_not_reached("Unknown action.");
 340         }
 341
 342         return 0;
 343 }
 344
 345 DEFINE_MAIN_FUNCTION(run);