fsck.c

   1 #include "cache.h"
   2 #include "object-store.h"
   3 #include "repository.h"
   4 #include "object.h"
   5 #include "blob.h"
   6 #include "tree.h"
   7 #include "tree-walk.h"
   8 #include "commit.h"
   9 #include "tag.h"
  10 #include "fsck.h"
  11 #include "refs.h"
  12 #include "url.h"
  13 #include "utf8.h"
  14 #include "decorate.h"
  15 #include "oidset.h"
  16 #include "packfile.h"
  17 #include "submodule-config.h"
  18 #include "config.h"
  19 #include "credential.h"
  20 #include "help.h"
  21
  22 #define STR(x) #x
  23 #define MSG_ID(id, msg_type) { STR(id), NULL, NULL, FSCK_##msg_type },
  24 static struct {
  25         const char *id_string;
  26         const char *downcased;
  27         const char *camelcased;
  28         enum fsck_msg_type msg_type;
  29 } msg_id_info[FSCK_MSG_MAX + 1] = {
  30         FOREACH_FSCK_MSG_ID(MSG_ID)
  31         { NULL, NULL, NULL, -1 }
  32 };
  33 #undef MSG_ID
  34 #undef STR
  35
  36 static void prepare_msg_ids(void)
  37 {
  38         int i;
  39
  40         if (msg_id_info[0].downcased)
  41                 return;
  42
  43         /* convert id_string to lower case, without underscores. */
  44         for (i = 0; i < FSCK_MSG_MAX; i++) {
  45                 const char *p = msg_id_info[i].id_string;
  46                 int len = strlen(p);
  47                 char *q = xmalloc(len);
  48
  49                 msg_id_info[i].downcased = q;
  50                 while (*p)
  51                         if (*p == '_')
  52                                 p++;
  53                         else
  54                                 *(q)++ = tolower(*(p)++);
  55                 *q = '\0';
  56
  57                 p = msg_id_info[i].id_string;
  58                 q = xmalloc(len);
  59                 msg_id_info[i].camelcased = q;
  60                 while (*p) {
  61                         if (*p == '_') {
  62                                 p++;
  63                                 if (*p)
  64                                         *q++ = *p++;
  65                         } else {
  66                                 *q++ = tolower(*p++);
  67                         }
  68                 }
  69                 *q = '\0';
  70         }
  71 }
  72
  73 static int parse_msg_id(const char *text)
  74 {
  75         int i;
  76
  77         prepare_msg_ids();
  78
  79         for (i = 0; i < FSCK_MSG_MAX; i++)
  80                 if (!strcmp(text, msg_id_info[i].downcased))
  81                         return i;
  82
  83         return -1;
  84 }
  85
  86 void list_config_fsck_msg_ids(struct string_list *list, const char *prefix)
  87 {
  88         int i;
  89
  90         prepare_msg_ids();
  91
  92         for (i = 0; i < FSCK_MSG_MAX; i++)
  93                 list_config_item(list, prefix, msg_id_info[i].camelcased);
  94 }
  95
  96 static enum fsck_msg_type fsck_msg_type(enum fsck_msg_id msg_id,
  97         struct fsck_options *options)
  98 {
  99         assert(msg_id >= 0 && msg_id < FSCK_MSG_MAX);
 100
 101         if (!options->msg_type) {
 102                 enum fsck_msg_type msg_type = msg_id_info[msg_id].msg_type;
 103
 104                 if (options->strict && msg_type == FSCK_WARN)
 105                         msg_type = FSCK_ERROR;
 106                 return msg_type;
 107         }
 108
 109         return options->msg_type[msg_id];
 110 }
 111
 112 static enum fsck_msg_type parse_msg_type(const char *str)
 113 {
 114         if (!strcmp(str, "error"))
 115                 return FSCK_ERROR;
 116         else if (!strcmp(str, "warn"))
 117                 return FSCK_WARN;
 118         else if (!strcmp(str, "ignore"))
 119                 return FSCK_IGNORE;
 120         else
 121                 die("Unknown fsck message type: '%s'", str);
 122 }
 123
 124 int is_valid_msg_type(const char *msg_id, const char *msg_type)
 125 {
 126         if (parse_msg_id(msg_id) < 0)
 127                 return 0;
 128         parse_msg_type(msg_type);
 129         return 1;
 130 }
 131
 132 void fsck_set_msg_type_from_ids(struct fsck_options *options,
 133                                 enum fsck_msg_id msg_id,
 134                                 enum fsck_msg_type msg_type)
 135 {
 136         if (!options->msg_type) {
 137                 int i;
 138                 enum fsck_msg_type *severity;
 139                 ALLOC_ARRAY(severity, FSCK_MSG_MAX);
 140                 for (i = 0; i < FSCK_MSG_MAX; i++)
 141                         severity[i] = fsck_msg_type(i, options);
 142                 options->msg_type = severity;
 143         }
 144
 145         options->msg_type[msg_id] = msg_type;
 146 }
 147
 148 void fsck_set_msg_type(struct fsck_options *options,
 149                        const char *msg_id_str, const char *msg_type_str)
 150 {
 151         int msg_id = parse_msg_id(msg_id_str);
 152         enum fsck_msg_type msg_type = parse_msg_type(msg_type_str);
 153
 154         if (msg_id < 0)
 155                 die("Unhandled message id: %s", msg_id_str);
 156
 157         if (msg_type != FSCK_ERROR && msg_id_info[msg_id].msg_type == FSCK_FATAL)
 158                 die("Cannot demote %s to %s", msg_id_str, msg_type_str);
 159
 160         fsck_set_msg_type_from_ids(options, msg_id, msg_type);
 161 }
 162
 163 void fsck_set_msg_types(struct fsck_options *options, const char *values)
 164 {
 165         char *buf = xstrdup(values), *to_free = buf;
 166         int done = 0;
 167
 168         while (!done) {
 169                 int len = strcspn(buf, " ,|"), equal;
 170
 171                 done = !buf[len];
 172                 if (!len) {
 173                         buf++;
 174                         continue;
 175                 }
 176                 buf[len] = '\0';
 177
 178                 for (equal = 0;
 179                      equal < len && buf[equal] != '=' && buf[equal] != ':';
 180                      equal++)
 181                         buf[equal] = tolower(buf[equal]);
 182                 buf[equal] = '\0';
 183
 184                 if (!strcmp(buf, "skiplist")) {
 185                         if (equal == len)
 186                                 die("skiplist requires a path");
 187                         oidset_parse_file(&options->skiplist, buf + equal + 1);
 188                         buf += len + 1;
 189                         continue;
 190                 }
 191
 192                 if (equal == len)
 193                         die("Missing '=': '%s'", buf);
 194
 195                 fsck_set_msg_type(options, buf, buf + equal + 1);
 196                 buf += len + 1;
 197         }
 198         free(to_free);
 199 }
 200
 201 static int object_on_skiplist(struct fsck_options *opts,
 202                               const struct object_id *oid)
 203 {
 204         return opts && oid && oidset_contains(&opts->skiplist, oid);
 205 }
 206
 207 __attribute__((format (printf, 5, 6)))
 208 static int report(struct fsck_options *options,
 209                   const struct object_id *oid, enum object_type object_type,
 210                   enum fsck_msg_id msg_id, const char *fmt, ...)
 211 {
 212         va_list ap;
 213         struct strbuf sb = STRBUF_INIT;
 214         enum fsck_msg_type msg_type = fsck_msg_type(msg_id, options);
 215         int result;
 216
 217         if (msg_type == FSCK_IGNORE)
 218                 return 0;
 219
 220         if (object_on_skiplist(options, oid))
 221                 return 0;
 222
 223         if (msg_type == FSCK_FATAL)
 224                 msg_type = FSCK_ERROR;
 225         else if (msg_type == FSCK_INFO)
 226                 msg_type = FSCK_WARN;
 227
 228         prepare_msg_ids();
 229         strbuf_addf(&sb, "%s: ", msg_id_info[msg_id].camelcased);
 230
 231         va_start(ap, fmt);
 232         strbuf_vaddf(&sb, fmt, ap);
 233         result = options->error_func(options, oid, object_type,
 234                                      msg_type, msg_id, sb.buf);
 235         strbuf_release(&sb);
 236         va_end(ap);
 237
 238         return result;
 239 }
 240
 241 void fsck_enable_object_names(struct fsck_options *options)
 242 {
 243         if (!options->object_names)
 244                 options->object_names = kh_init_oid_map();
 245 }
 246
 247 const char *fsck_get_object_name(struct fsck_options *options,
 248                                  const struct object_id *oid)
 249 {
 250         khiter_t pos;
 251         if (!options->object_names)
 252                 return NULL;
 253         pos = kh_get_oid_map(options->object_names, *oid);
 254         if (pos >= kh_end(options->object_names))
 255                 return NULL;
 256         return kh_value(options->object_names, pos);
 257 }
 258
 259 void fsck_put_object_name(struct fsck_options *options,
 260                           const struct object_id *oid,
 261                           const char *fmt, ...)
 262 {
 263         va_list ap;
 264         struct strbuf buf = STRBUF_INIT;
 265         khiter_t pos;
 266         int hashret;
 267
 268         if (!options->object_names)
 269                 return;
 270
 271         pos = kh_put_oid_map(options->object_names, *oid, &hashret);
 272         if (!hashret)
 273                 return;
 274         va_start(ap, fmt);
 275         strbuf_vaddf(&buf, fmt, ap);
 276         kh_value(options->object_names, pos) = strbuf_detach(&buf, NULL);
 277         va_end(ap);
 278 }
 279
 280 const char *fsck_describe_object(struct fsck_options *options,
 281                                  const struct object_id *oid)
 282 {
 283         static struct strbuf bufs[] = {
 284                 STRBUF_INIT, STRBUF_INIT, STRBUF_INIT, STRBUF_INIT
 285         };
 286         static int b = 0;
 287         struct strbuf *buf;
 288         const char *name = fsck_get_object_name(options, oid);
 289
 290         buf = bufs + b;
 291         b = (b + 1) % ARRAY_SIZE(bufs);
 292         strbuf_reset(buf);
 293         strbuf_addstr(buf, oid_to_hex(oid));
 294         if (name)
 295                 strbuf_addf(buf, " (%s)", name);
 296
 297         return buf->buf;
 298 }
 299
 300 static int fsck_walk_tree(struct tree *tree, void *data, struct fsck_options *options)
 301 {
 302         struct tree_desc desc;
 303         struct name_entry entry;
 304         int res = 0;
 305         const char *name;
 306
 307         if (parse_tree(tree))
 308                 return -1;
 309
 310         name = fsck_get_object_name(options, &tree->object.oid);
 311         if (init_tree_desc_gently(&desc, tree->buffer, tree->size, 0))
 312                 return -1;
 313         while (tree_entry_gently(&desc, &entry)) {
 314                 struct object *obj;
 315                 int result;
 316
 317                 if (S_ISGITLINK(entry.mode))
 318                         continue;
 319
 320                 if (S_ISDIR(entry.mode)) {
 321                         obj = (struct object *)lookup_tree(the_repository, &entry.oid);
 322                         if (name && obj)
 323                                 fsck_put_object_name(options, &entry.oid, "%s%s/",
 324                                                      name, entry.path);
 325                         result = options->walk(obj, OBJ_TREE, data, options);
 326                 }
 327                 else if (S_ISREG(entry.mode) || S_ISLNK(entry.mode)) {
 328                         obj = (struct object *)lookup_blob(the_repository, &entry.oid);
 329                         if (name && obj)
 330                                 fsck_put_object_name(options, &entry.oid, "%s%s",
 331                                                      name, entry.path);
 332                         result = options->walk(obj, OBJ_BLOB, data, options);
 333                 }
 334                 else {
 335                         result = error("in tree %s: entry %s has bad mode %.6o",
 336                                        fsck_describe_object(options, &tree->object.oid),
 337                                        entry.path, entry.mode);
 338                 }
 339                 if (result < 0)
 340                         return result;
 341                 if (!res)
 342                         res = result;
 343         }
 344         return res;
 345 }
 346
 347 static int fsck_walk_commit(struct commit *commit, void *data, struct fsck_options *options)
 348 {
 349         int counter = 0, generation = 0, name_prefix_len = 0;
 350         struct commit_list *parents;
 351         int res;
 352         int result;
 353         const char *name;
 354
 355         if (parse_commit(commit))
 356                 return -1;
 357
 358         name = fsck_get_object_name(options, &commit->object.oid);
 359         if (name)
 360                 fsck_put_object_name(options, get_commit_tree_oid(commit),
 361                                      "%s:", name);
 362
 363         result = options->walk((struct object *)get_commit_tree(commit),
 364                                OBJ_TREE, data, options);
 365         if (result < 0)
 366                 return result;
 367         res = result;
 368
 369         parents = commit->parents;
 370         if (name && parents) {
 371                 int len = strlen(name), power;
 372
 373                 if (len && name[len - 1] == '^') {
 374                         generation = 1;
 375                         name_prefix_len = len - 1;
 376                 }
 377                 else { /* parse ~<generation> suffix */
 378                         for (generation = 0, power = 1;
 379                              len && isdigit(name[len - 1]);
 380                              power *= 10)
 381                                 generation += power * (name[--len] - '0');
 382                         if (power > 1 && len && name[len - 1] == '~')
 383                                 name_prefix_len = len - 1;
 384                         else {
 385                                 /* Maybe a non-first parent, e.g. HEAD^2 */
 386                                 generation = 0;
 387                                 name_prefix_len = len;
 388                         }
 389                 }
 390         }
 391
 392         while (parents) {
 393                 if (name) {
 394                         struct object_id *oid = &parents->item->object.oid;
 395
 396                         if (counter++)
 397                                 fsck_put_object_name(options, oid, "%s^%d",
 398                                                      name, counter);
 399                         else if (generation > 0)
 400                                 fsck_put_object_name(options, oid, "%.*s~%d",
 401                                                      name_prefix_len, name,
 402                                                      generation + 1);
 403                         else
 404                                 fsck_put_object_name(options, oid, "%s^", name);
 405                 }
 406                 result = options->walk((struct object *)parents->item, OBJ_COMMIT, data, options);
 407                 if (result < 0)
 408                         return result;
 409                 if (!res)
 410                         res = result;
 411                 parents = parents->next;
 412         }
 413         return res;
 414 }
 415
 416 static int fsck_walk_tag(struct tag *tag, void *data, struct fsck_options *options)
 417 {
 418         const char *name = fsck_get_object_name(options, &tag->object.oid);
 419
 420         if (parse_tag(tag))
 421                 return -1;
 422         if (name)
 423                 fsck_put_object_name(options, &tag->tagged->oid, "%s", name);
 424         return options->walk(tag->tagged, OBJ_ANY, data, options);
 425 }
 426
 427 int fsck_walk(struct object *obj, void *data, struct fsck_options *options)
 428 {
 429         if (!obj)
 430                 return -1;
 431
 432         if (obj->type == OBJ_NONE)
 433                 parse_object(the_repository, &obj->oid);
 434
 435         switch (obj->type) {
 436         case OBJ_BLOB:
 437                 return 0;
 438         case OBJ_TREE:
 439                 return fsck_walk_tree((struct tree *)obj, data, options);
 440         case OBJ_COMMIT:
 441                 return fsck_walk_commit((struct commit *)obj, data, options);
 442         case OBJ_TAG:
 443                 return fsck_walk_tag((struct tag *)obj, data, options);
 444         default:
 445                 error("Unknown object type for %s",
 446                       fsck_describe_object(options, &obj->oid));
 447                 return -1;
 448         }
 449 }
 450
 451 struct name_stack {
 452         const char **names;
 453         size_t nr, alloc;
 454 };
 455
 456 static void name_stack_push(struct name_stack *stack, const char *name)
 457 {
 458         ALLOC_GROW(stack->names, stack->nr + 1, stack->alloc);
 459         stack->names[stack->nr++] = name;
 460 }
 461
 462 static const char *name_stack_pop(struct name_stack *stack)
 463 {
 464         return stack->nr ? stack->names[--stack->nr] : NULL;
 465 }
 466
 467 static void name_stack_clear(struct name_stack *stack)
 468 {
 469         FREE_AND_NULL(stack->names);
 470         stack->nr = stack->alloc = 0;
 471 }
 472
 473 /*
 474  * The entries in a tree are ordered in the _path_ order,
 475  * which means that a directory entry is ordered by adding
 476  * a slash to the end of it.
 477  *
 478  * So a directory called "a" is ordered _after_ a file
 479  * called "a.c", because "a/" sorts after "a.c".
 480  */
 481 #define TREE_UNORDERED (-1)
 482 #define TREE_HAS_DUPS  (-2)
 483
 484 static int is_less_than_slash(unsigned char c)
 485 {
 486         return '\0' < c && c < '/';
 487 }
 488
 489 static int verify_ordered(unsigned mode1, const char *name1,
 490                           unsigned mode2, const char *name2,
 491                           struct name_stack *candidates)
 492 {
 493         int len1 = strlen(name1);
 494         int len2 = strlen(name2);
 495         int len = len1 < len2 ? len1 : len2;
 496         unsigned char c1, c2;
 497         int cmp;
 498
 499         cmp = memcmp(name1, name2, len);
 500         if (cmp < 0)
 501                 return 0;
 502         if (cmp > 0)
 503                 return TREE_UNORDERED;
 504
 505         /*
 506          * Ok, the first <len> characters are the same.
 507          * Now we need to order the next one, but turn
 508          * a '\0' into a '/' for a directory entry.
 509          */
 510         c1 = name1[len];
 511         c2 = name2[len];
 512         if (!c1 && !c2)
 513                 /*
 514                  * git-write-tree used to write out a nonsense tree that has
 515                  * entries with the same name, one blob and one tree.  Make
 516                  * sure we do not have duplicate entries.
 517                  */
 518                 return TREE_HAS_DUPS;
 519         if (!c1 && S_ISDIR(mode1))
 520                 c1 = '/';
 521         if (!c2 && S_ISDIR(mode2))
 522                 c2 = '/';
 523
 524         /*
 525          * There can be non-consecutive duplicates due to the implicitly
 526          * added slash, e.g.:
 527          *
 528          *   foo
 529          *   foo.bar
 530          *   foo.bar.baz
 531          *   foo.bar/
 532          *   foo/
 533          *
 534          * Record non-directory candidates (like "foo" and "foo.bar" in
 535          * the example) on a stack and check directory candidates (like
 536          * foo/" and "foo.bar/") against that stack.
 537          */
 538         if (!c1 && is_less_than_slash(c2)) {
 539                 name_stack_push(candidates, name1);
 540         } else if (c2 == '/' && is_less_than_slash(c1)) {
 541                 for (;;) {
 542                         const char *p;
 543                         const char *f_name = name_stack_pop(candidates);
 544
 545                         if (!f_name)
 546                                 break;
 547                         if (!skip_prefix(name2, f_name, &p))
 548                                 continue;
 549                         if (!*p)
 550                                 return TREE_HAS_DUPS;
 551                         if (is_less_than_slash(*p)) {
 552                                 name_stack_push(candidates, f_name);
 553                                 break;
 554                         }
 555                 }
 556         }
 557
 558         return c1 < c2 ? 0 : TREE_UNORDERED;
 559 }
 560
 561 static int fsck_tree(const struct object_id *tree_oid,
 562                      const char *buffer, unsigned long size,
 563                      struct fsck_options *options)
 564 {
 565         int retval = 0;
 566         int has_null_sha1 = 0;
 567         int has_full_path = 0;
 568         int has_empty_name = 0;
 569         int has_dot = 0;
 570         int has_dotdot = 0;
 571         int has_dotgit = 0;
 572         int has_zero_pad = 0;
 573         int has_bad_modes = 0;
 574         int has_dup_entries = 0;
 575         int not_properly_sorted = 0;
 576         struct tree_desc desc;
 577         unsigned o_mode;
 578         const char *o_name;
 579         struct name_stack df_dup_candidates = { NULL };
 580
 581         if (init_tree_desc_gently(&desc, buffer, size, TREE_DESC_RAW_MODES)) {
 582                 retval += report(options, tree_oid, OBJ_TREE,
 583                                  FSCK_MSG_BAD_TREE,
 584                                  "cannot be parsed as a tree");
 585                 return retval;
 586         }
 587
 588         o_mode = 0;
 589         o_name = NULL;
 590
 591         while (desc.size) {
 592                 unsigned short mode;
 593                 const char *name, *backslash;
 594                 const struct object_id *entry_oid;
 595
 596                 entry_oid = tree_entry_extract(&desc, &name, &mode);
 597
 598                 has_null_sha1 |= is_null_oid(entry_oid);
 599                 has_full_path |= !!strchr(name, '/');
 600                 has_empty_name |= !*name;
 601                 has_dot |= !strcmp(name, ".");
 602                 has_dotdot |= !strcmp(name, "..");
 603                 has_dotgit |= is_hfs_dotgit(name) || is_ntfs_dotgit(name);
 604                 has_zero_pad |= *(char *)desc.buffer == '0';
 605
 606                 if (is_hfs_dotgitmodules(name) || is_ntfs_dotgitmodules(name)) {
 607                         if (!S_ISLNK(mode))
 608                                 oidset_insert(&options->gitmodules_found,
 609                                               entry_oid);
 610                         else
 611                                 retval += report(options,
 612                                                  tree_oid, OBJ_TREE,
 613                                                  FSCK_MSG_GITMODULES_SYMLINK,
 614                                                  ".gitmodules is a symbolic link");
 615                 }
 616
 617                 if (S_ISLNK(mode)) {
 618                         if (is_hfs_dotgitignore(name) ||
 619                             is_ntfs_dotgitignore(name))
 620                                 retval += report(options, tree_oid, OBJ_TREE,
 621                                                  FSCK_MSG_GITIGNORE_SYMLINK,
 622                                                  ".gitignore is a symlink");
 623                         if (is_hfs_dotgitattributes(name) ||
 624                             is_ntfs_dotgitattributes(name))
 625                                 retval += report(options, tree_oid, OBJ_TREE,
 626                                                  FSCK_MSG_GITATTRIBUTES_SYMLINK,
 627                                                  ".gitattributes is a symlink");
 628                         if (is_hfs_dotmailmap(name) ||
 629                             is_ntfs_dotmailmap(name))
 630                                 retval += report(options, tree_oid, OBJ_TREE,
 631                                                  FSCK_MSG_MAILMAP_SYMLINK,
 632                                                  ".mailmap is a symlink");
 633                 }
 634
 635                 if ((backslash = strchr(name, '\\'))) {
 636                         while (backslash) {
 637                                 backslash++;
 638                                 has_dotgit |= is_ntfs_dotgit(backslash);
 639                                 if (is_ntfs_dotgitmodules(backslash)) {
 640                                         if (!S_ISLNK(mode))
 641                                                 oidset_insert(&options->gitmodules_found,
 642                                                               entry_oid);
 643                                         else
 644                                                 retval += report(options, tree_oid, OBJ_TREE,
 645                                                                  FSCK_MSG_GITMODULES_SYMLINK,
 646                                                                  ".gitmodules is a symbolic link");
 647                                 }
 648                                 backslash = strchr(backslash, '\\');
 649                         }
 650                 }
 651
 652                 if (update_tree_entry_gently(&desc)) {
 653                         retval += report(options, tree_oid, OBJ_TREE,
 654                                          FSCK_MSG_BAD_TREE,
 655                                          "cannot be parsed as a tree");
 656                         break;
 657                 }
 658
 659                 switch (mode) {
 660                 /*
 661                  * Standard modes..
 662                  */
 663                 case S_IFREG | 0755:
 664                 case S_IFREG | 0644:
 665                 case S_IFLNK:
 666                 case S_IFDIR:
 667                 case S_IFGITLINK:
 668                         break;
 669                 /*
 670                  * This is nonstandard, but we had a few of these
 671                  * early on when we honored the full set of mode
 672                  * bits..
 673                  */
 674                 case S_IFREG | 0664:
 675                         if (!options->strict)
 676                                 break;
 677                         /* fallthrough */
 678                 default:
 679                         has_bad_modes = 1;
 680                 }
 681
 682                 if (o_name) {
 683                         switch (verify_ordered(o_mode, o_name, mode, name,
 684                                                &df_dup_candidates)) {
 685                         case TREE_UNORDERED:
 686                                 not_properly_sorted = 1;
 687                                 break;
 688                         case TREE_HAS_DUPS:
 689                                 has_dup_entries = 1;
 690                                 break;
 691                         default:
 692                                 break;
 693                         }
 694                 }
 695
 696                 o_mode = mode;
 697                 o_name = name;
 698         }
 699
 700         name_stack_clear(&df_dup_candidates);
 701
 702         if (has_null_sha1)
 703                 retval += report(options, tree_oid, OBJ_TREE,
 704                                  FSCK_MSG_NULL_SHA1,
 705                                  "contains entries pointing to null sha1");
 706         if (has_full_path)
 707                 retval += report(options, tree_oid, OBJ_TREE,
 708                                  FSCK_MSG_FULL_PATHNAME,
 709                                  "contains full pathnames");
 710         if (has_empty_name)
 711                 retval += report(options, tree_oid, OBJ_TREE,
 712                                  FSCK_MSG_EMPTY_NAME,
 713                                  "contains empty pathname");
 714         if (has_dot)
 715                 retval += report(options, tree_oid, OBJ_TREE,
 716                                  FSCK_MSG_HAS_DOT,
 717                                  "contains '.'");
 718         if (has_dotdot)
 719                 retval += report(options, tree_oid, OBJ_TREE,
 720                                  FSCK_MSG_HAS_DOTDOT,
 721                                  "contains '..'");
 722         if (has_dotgit)
 723                 retval += report(options, tree_oid, OBJ_TREE,
 724                                  FSCK_MSG_HAS_DOTGIT,
 725                                  "contains '.git'");
 726         if (has_zero_pad)
 727                 retval += report(options, tree_oid, OBJ_TREE,
 728                                  FSCK_MSG_ZERO_PADDED_FILEMODE,
 729                                  "contains zero-padded file modes");
 730         if (has_bad_modes)
 731                 retval += report(options, tree_oid, OBJ_TREE,
 732                                  FSCK_MSG_BAD_FILEMODE,
 733                                  "contains bad file modes");
 734         if (has_dup_entries)
 735                 retval += report(options, tree_oid, OBJ_TREE,
 736                                  FSCK_MSG_DUPLICATE_ENTRIES,
 737                                  "contains duplicate file entries");
 738         if (not_properly_sorted)
 739                 retval += report(options, tree_oid, OBJ_TREE,
 740                                  FSCK_MSG_TREE_NOT_SORTED,
 741                                  "not properly sorted");
 742         return retval;
 743 }
 744
 745 static int verify_headers(const void *data, unsigned long size,
 746                           const struct object_id *oid, enum object_type type,
 747                           struct fsck_options *options)
 748 {
 749         const char *buffer = (const char *)data;
 750         unsigned long i;
 751
 752         for (i = 0; i < size; i++) {
 753                 switch (buffer[i]) {
 754                 case '\0':
 755                         return report(options, oid, type,
 756                                 FSCK_MSG_NUL_IN_HEADER,
 757                                 "unterminated header: NUL at offset %ld", i);
 758                 case '\n':
 759                         if (i + 1 < size && buffer[i + 1] == '\n')
 760                                 return 0;
 761                 }
 762         }
 763
 764         /*
 765          * We did not find double-LF that separates the header
 766          * and the body.  Not having a body is not a crime but
 767          * we do want to see the terminating LF for the last header
 768          * line.
 769          */
 770         if (size && buffer[size - 1] == '\n')
 771                 return 0;
 772
 773         return report(options, oid, type,
 774                 FSCK_MSG_UNTERMINATED_HEADER, "unterminated header");
 775 }
 776
 777 static int fsck_ident(const char **ident,
 778                       const struct object_id *oid, enum object_type type,
 779                       struct fsck_options *options)
 780 {
 781         const char *p = *ident;
 782         char *end;
 783
 784         *ident = strchrnul(*ident, '\n');
 785         if (**ident == '\n')
 786                 (*ident)++;
 787
 788         if (*p == '<')
 789                 return report(options, oid, type, FSCK_MSG_MISSING_NAME_BEFORE_EMAIL, "invalid author/committer line - missing space before email");
 790         p += strcspn(p, "<>\n");
 791         if (*p == '>')
 792                 return report(options, oid, type, FSCK_MSG_BAD_NAME, "invalid author/committer line - bad name");
 793         if (*p != '<')
 794                 return report(options, oid, type, FSCK_MSG_MISSING_EMAIL, "invalid author/committer line - missing email");
 795         if (p[-1] != ' ')
 796                 return report(options, oid, type, FSCK_MSG_MISSING_SPACE_BEFORE_EMAIL, "invalid author/committer line - missing space before email");
 797         p++;
 798         p += strcspn(p, "<>\n");
 799         if (*p != '>')
 800                 return report(options, oid, type, FSCK_MSG_BAD_EMAIL, "invalid author/committer line - bad email");
 801         p++;
 802         if (*p != ' ')
 803                 return report(options, oid, type, FSCK_MSG_MISSING_SPACE_BEFORE_DATE, "invalid author/committer line - missing space before date");
 804         p++;
 805         if (*p == '0' && p[1] != ' ')
 806                 return report(options, oid, type, FSCK_MSG_ZERO_PADDED_DATE, "invalid author/committer line - zero-padded date");
 807         if (date_overflows(parse_timestamp(p, &end, 10)))
 808                 return report(options, oid, type, FSCK_MSG_BAD_DATE_OVERFLOW, "invalid author/committer line - date causes integer overflow");
 809         if ((end == p || *end != ' '))
 810                 return report(options, oid, type, FSCK_MSG_BAD_DATE, "invalid author/committer line - bad date");
 811         p = end + 1;
 812         if ((*p != '+' && *p != '-') ||
 813             !isdigit(p[1]) ||
 814             !isdigit(p[2]) ||
 815             !isdigit(p[3]) ||
 816             !isdigit(p[4]) ||
 817             (p[5] != '\n'))
 818                 return report(options, oid, type, FSCK_MSG_BAD_TIMEZONE, "invalid author/committer line - bad time zone");
 819         p += 6;
 820         return 0;
 821 }
 822
 823 static int fsck_commit(const struct object_id *oid,
 824                        const char *buffer, unsigned long size,
 825                        struct fsck_options *options)
 826 {
 827         struct object_id tree_oid, parent_oid;
 828         unsigned author_count;
 829         int err;
 830         const char *buffer_begin = buffer;
 831         const char *p;
 832
 833         if (verify_headers(buffer, size, oid, OBJ_COMMIT, options))
 834                 return -1;
 835
 836         if (!skip_prefix(buffer, "tree ", &buffer))
 837                 return report(options, oid, OBJ_COMMIT, FSCK_MSG_MISSING_TREE, "invalid format - expected 'tree' line");
 838         if (parse_oid_hex(buffer, &tree_oid, &p) || *p != '\n') {
 839                 err = report(options, oid, OBJ_COMMIT, FSCK_MSG_BAD_TREE_SHA1, "invalid 'tree' line format - bad sha1");
 840                 if (err)
 841                         return err;
 842         }
 843         buffer = p + 1;
 844         while (skip_prefix(buffer, "parent ", &buffer)) {
 845                 if (parse_oid_hex(buffer, &parent_oid, &p) || *p != '\n') {
 846                         err = report(options, oid, OBJ_COMMIT, FSCK_MSG_BAD_PARENT_SHA1, "invalid 'parent' line format - bad sha1");
 847                         if (err)
 848                                 return err;
 849                 }
 850                 buffer = p + 1;
 851         }
 852         author_count = 0;
 853         while (skip_prefix(buffer, "author ", &buffer)) {
 854                 author_count++;
 855                 err = fsck_ident(&buffer, oid, OBJ_COMMIT, options);
 856                 if (err)
 857                         return err;
 858         }
 859         if (author_count < 1)
 860                 err = report(options, oid, OBJ_COMMIT, FSCK_MSG_MISSING_AUTHOR, "invalid format - expected 'author' line");
 861         else if (author_count > 1)
 862                 err = report(options, oid, OBJ_COMMIT, FSCK_MSG_MULTIPLE_AUTHORS, "invalid format - multiple 'author' lines");
 863         if (err)
 864                 return err;
 865         if (!skip_prefix(buffer, "committer ", &buffer))
 866                 return report(options, oid, OBJ_COMMIT, FSCK_MSG_MISSING_COMMITTER, "invalid format - expected 'committer' line");
 867         err = fsck_ident(&buffer, oid, OBJ_COMMIT, options);
 868         if (err)
 869                 return err;
 870         if (memchr(buffer_begin, '\0', size)) {
 871                 err = report(options, oid, OBJ_COMMIT, FSCK_MSG_NUL_IN_COMMIT,
 872                              "NUL byte in the commit object body");
 873                 if (err)
 874                         return err;
 875         }
 876         return 0;
 877 }
 878
 879 static int fsck_tag(const struct object_id *oid, const char *buffer,
 880                     unsigned long size, struct fsck_options *options)
 881 {
 882         struct object_id tagged_oid;
 883         int tagged_type;
 884         return fsck_tag_standalone(oid, buffer, size, options, &tagged_oid,
 885                                    &tagged_type);
 886 }
 887
 888 int fsck_tag_standalone(const struct object_id *oid, const char *buffer,
 889                         unsigned long size, struct fsck_options *options,
 890                         struct object_id *tagged_oid,
 891                         int *tagged_type)
 892 {
 893         int ret = 0;
 894         char *eol;
 895         struct strbuf sb = STRBUF_INIT;
 896         const char *p;
 897
 898         ret = verify_headers(buffer, size, oid, OBJ_TAG, options);
 899         if (ret)
 900                 goto done;
 901
 902         if (!skip_prefix(buffer, "object ", &buffer)) {
 903                 ret = report(options, oid, OBJ_TAG, FSCK_MSG_MISSING_OBJECT, "invalid format - expected 'object' line");
 904                 goto done;
 905         }
 906         if (parse_oid_hex(buffer, tagged_oid, &p) || *p != '\n') {
 907                 ret = report(options, oid, OBJ_TAG, FSCK_MSG_BAD_OBJECT_SHA1, "invalid 'object' line format - bad sha1");
 908                 if (ret)
 909                         goto done;
 910         }
 911         buffer = p + 1;
 912
 913         if (!skip_prefix(buffer, "type ", &buffer)) {
 914                 ret = report(options, oid, OBJ_TAG, FSCK_MSG_MISSING_TYPE_ENTRY, "invalid format - expected 'type' line");
 915                 goto done;
 916         }
 917         eol = strchr(buffer, '\n');
 918         if (!eol) {
 919                 ret = report(options, oid, OBJ_TAG, FSCK_MSG_MISSING_TYPE, "invalid format - unexpected end after 'type' line");
 920                 goto done;
 921         }
 922         *tagged_type = type_from_string_gently(buffer, eol - buffer, 1);
 923         if (*tagged_type < 0)
 924                 ret = report(options, oid, OBJ_TAG, FSCK_MSG_BAD_TYPE, "invalid 'type' value");
 925         if (ret)
 926                 goto done;
 927         buffer = eol + 1;
 928
 929         if (!skip_prefix(buffer, "tag ", &buffer)) {
 930                 ret = report(options, oid, OBJ_TAG, FSCK_MSG_MISSING_TAG_ENTRY, "invalid format - expected 'tag' line");
 931                 goto done;
 932         }
 933         eol = strchr(buffer, '\n');
 934         if (!eol) {
 935                 ret = report(options, oid, OBJ_TAG, FSCK_MSG_MISSING_TAG, "invalid format - unexpected end after 'type' line");
 936                 goto done;
 937         }
 938         strbuf_addf(&sb, "refs/tags/%.*s", (int)(eol - buffer), buffer);
 939         if (check_refname_format(sb.buf, 0)) {
 940                 ret = report(options, oid, OBJ_TAG,
 941                              FSCK_MSG_BAD_TAG_NAME,
 942                              "invalid 'tag' name: %.*s",
 943                              (int)(eol - buffer), buffer);
 944                 if (ret)
 945                         goto done;
 946         }
 947         buffer = eol + 1;
 948
 949         if (!skip_prefix(buffer, "tagger ", &buffer)) {
 950                 /* early tags do not contain 'tagger' lines; warn only */
 951                 ret = report(options, oid, OBJ_TAG, FSCK_MSG_MISSING_TAGGER_ENTRY, "invalid format - expected 'tagger' line");
 952                 if (ret)
 953                         goto done;
 954         }
 955         else
 956                 ret = fsck_ident(&buffer, oid, OBJ_TAG, options);
 957         if (!*buffer)
 958                 goto done;
 959
 960         if (!starts_with(buffer, "\n")) {
 961                 /*
 962                  * The verify_headers() check will allow
 963                  * e.g. "[...]tagger <tagger>\nsome
 964                  * garbage\n\nmessage" to pass, thinking "some
 965                  * garbage" could be a custom header. E.g. "mktag"
 966                  * doesn't want any unknown headers.
 967                  */
 968                 ret = report(options, oid, OBJ_TAG, FSCK_MSG_EXTRA_HEADER_ENTRY, "invalid format - extra header(s) after 'tagger'");
 969                 if (ret)
 970                         goto done;
 971         }
 972
 973 done:
 974         strbuf_release(&sb);
 975         return ret;
 976 }
 977
 978 static int starts_with_dot_slash(const char *const path)
 979 {
 980         return path_match_flags(path, PATH_MATCH_STARTS_WITH_DOT_SLASH |
 981                                 PATH_MATCH_XPLATFORM);
 982 }
 983
 984 static int starts_with_dot_dot_slash(const char *const path)
 985 {
 986         return path_match_flags(path, PATH_MATCH_STARTS_WITH_DOT_DOT_SLASH |
 987                                 PATH_MATCH_XPLATFORM);
 988 }
 989
 990 static int submodule_url_is_relative(const char *url)
 991 {
 992         return starts_with_dot_slash(url) || starts_with_dot_dot_slash(url);
 993 }
 994
 995 /*
 996  * Count directory components that a relative submodule URL should chop
 997  * from the remote_url it is to be resolved against.
 998  *
 999  * In other words, this counts "../" components at the start of a
1000  * submodule URL.
1001  *
1002  * Returns the number of directory components to chop and writes a
1003  * pointer to the next character of url after all leading "./" and
1004  * "../" components to out.
1005  */
1006 static int count_leading_dotdots(const char *url, const char **out)
1007 {
1008         int result = 0;
1009         while (1) {
1010                 if (starts_with_dot_dot_slash(url)) {
1011                         result++;
1012                         url += strlen("../");
1013                         continue;
1014                 }
1015                 if (starts_with_dot_slash(url)) {
1016                         url += strlen("./");
1017                         continue;
1018                 }
1019                 *out = url;
1020                 return result;
1021         }
1022 }
1023 /*
1024  * Check whether a transport is implemented by git-remote-curl.
1025  *
1026  * If it is, returns 1 and writes the URL that would be passed to
1027  * git-remote-curl to the "out" parameter.
1028  *
1029  * Otherwise, returns 0 and leaves "out" untouched.
1030  *
1031  * Examples:
1032  *   http::https://example.com/repo.git -> 1, https://example.com/repo.git
1033  *   https://example.com/repo.git -> 1, https://example.com/repo.git
1034  *   git://example.com/repo.git -> 0
1035  *
1036  * This is for use in checking for previously exploitable bugs that
1037  * required a submodule URL to be passed to git-remote-curl.
1038  */
1039 static int url_to_curl_url(const char *url, const char **out)
1040 {
1041         /*
1042          * We don't need to check for case-aliases, "http.exe", and so
1043          * on because in the default configuration, is_transport_allowed
1044          * prevents URLs with those schemes from being cloned
1045          * automatically.
1046          */
1047         if (skip_prefix(url, "http::", out) ||
1048             skip_prefix(url, "https::", out) ||
1049             skip_prefix(url, "ftp::", out) ||
1050             skip_prefix(url, "ftps::", out))
1051                 return 1;
1052         if (starts_with(url, "http://") ||
1053             starts_with(url, "https://") ||
1054             starts_with(url, "ftp://") ||
1055             starts_with(url, "ftps://")) {
1056                 *out = url;
1057                 return 1;
1058         }
1059         return 0;
1060 }
1061
1062 static int check_submodule_url(const char *url)
1063 {
1064         const char *curl_url;
1065
1066         if (looks_like_command_line_option(url))
1067                 return -1;
1068
1069         if (submodule_url_is_relative(url) || starts_with(url, "git://")) {
1070                 char *decoded;
1071                 const char *next;
1072                 int has_nl;
1073
1074                 /*
1075                  * This could be appended to an http URL and url-decoded;
1076                  * check for malicious characters.
1077                  */
1078                 decoded = url_decode(url);
1079                 has_nl = !!strchr(decoded, '\n');
1080
1081                 free(decoded);
1082                 if (has_nl)
1083                         return -1;
1084
1085                 /*
1086                  * URLs which escape their root via "../" can overwrite
1087                  * the host field and previous components, resolving to
1088                  * URLs like https::example.com/submodule.git and
1089                  * https:///example.com/submodule.git that were
1090                  * susceptible to CVE-2020-11008.
1091                  */
1092                 if (count_leading_dotdots(url, &next) > 0 &&
1093                     (*next == ':' || *next == '/'))
1094                         return -1;
1095         }
1096
1097         else if (url_to_curl_url(url, &curl_url)) {
1098                 struct credential c = CREDENTIAL_INIT;
1099                 int ret = 0;
1100                 if (credential_from_url_gently(&c, curl_url, 1) ||
1101                     !*c.host)
1102                         ret = -1;
1103                 credential_clear(&c);
1104                 return ret;
1105         }
1106
1107         return 0;
1108 }
1109
1110 struct fsck_gitmodules_data {
1111         const struct object_id *oid;
1112         struct fsck_options *options;
1113         int ret;
1114 };
1115
1116 static int fsck_gitmodules_fn(const char *var, const char *value, void *vdata)
1117 {
1118         struct fsck_gitmodules_data *data = vdata;
1119         const char *subsection, *key;
1120         size_t subsection_len;
1121         char *name;
1122
1123         if (parse_config_key(var, "submodule", &subsection, &subsection_len, &key) < 0 ||
1124             !subsection)
1125                 return 0;
1126
1127         name = xmemdupz(subsection, subsection_len);
1128         if (check_submodule_name(name) < 0)
1129                 data->ret |= report(data->options,
1130                                     data->oid, OBJ_BLOB,
1131                                     FSCK_MSG_GITMODULES_NAME,
1132                                     "disallowed submodule name: %s",
1133                                     name);
1134         if (!strcmp(key, "url") && value &&
1135             check_submodule_url(value) < 0)
1136                 data->ret |= report(data->options,
1137                                     data->oid, OBJ_BLOB,
1138                                     FSCK_MSG_GITMODULES_URL,
1139                                     "disallowed submodule url: %s",
1140                                     value);
1141         if (!strcmp(key, "path") && value &&
1142             looks_like_command_line_option(value))
1143                 data->ret |= report(data->options,
1144                                     data->oid, OBJ_BLOB,
1145                                     FSCK_MSG_GITMODULES_PATH,
1146                                     "disallowed submodule path: %s",
1147                                     value);
1148         if (!strcmp(key, "update") && value &&
1149             parse_submodule_update_type(value) == SM_UPDATE_COMMAND)
1150                 data->ret |= report(data->options, data->oid, OBJ_BLOB,
1151                                     FSCK_MSG_GITMODULES_UPDATE,
1152                                     "disallowed submodule update setting: %s",
1153                                     value);
1154         free(name);
1155
1156         return 0;
1157 }
1158
1159 static int fsck_blob(const struct object_id *oid, const char *buf,
1160                      unsigned long size, struct fsck_options *options)
1161 {
1162         struct fsck_gitmodules_data data;
1163         struct config_options config_opts = { 0 };
1164
1165         if (!oidset_contains(&options->gitmodules_found, oid))
1166                 return 0;
1167         oidset_insert(&options->gitmodules_done, oid);
1168
1169         if (object_on_skiplist(options, oid))
1170                 return 0;
1171
1172         if (!buf) {
1173                 /*
1174                  * A missing buffer here is a sign that the caller found the
1175                  * blob too gigantic to load into memory. Let's just consider
1176                  * that an error.
1177                  */
1178                 return report(options, oid, OBJ_BLOB,
1179                               FSCK_MSG_GITMODULES_LARGE,
1180                               ".gitmodules too large to parse");
1181         }
1182
1183         data.oid = oid;
1184         data.options = options;
1185         data.ret = 0;
1186         config_opts.error_action = CONFIG_ERROR_SILENT;
1187         if (git_config_from_mem(fsck_gitmodules_fn, CONFIG_ORIGIN_BLOB,
1188                                 ".gitmodules", buf, size, &data, &config_opts))
1189                 data.ret |= report(options, oid, OBJ_BLOB,
1190                                    FSCK_MSG_GITMODULES_PARSE,
1191                                    "could not parse gitmodules blob");
1192
1193         return data.ret;
1194 }
1195
1196 int fsck_object(struct object *obj, void *data, unsigned long size,
1197         struct fsck_options *options)
1198 {
1199         if (!obj)
1200                 return report(options, NULL, OBJ_NONE, FSCK_MSG_BAD_OBJECT_SHA1, "no valid object to fsck");
1201
1202         if (obj->type == OBJ_BLOB)
1203                 return fsck_blob(&obj->oid, data, size, options);
1204         if (obj->type == OBJ_TREE)
1205                 return fsck_tree(&obj->oid, data, size, options);
1206         if (obj->type == OBJ_COMMIT)
1207                 return fsck_commit(&obj->oid, data, size, options);
1208         if (obj->type == OBJ_TAG)
1209                 return fsck_tag(&obj->oid, data, size, options);
1210
1211         return report(options, &obj->oid, obj->type,
1212                       FSCK_MSG_UNKNOWN_TYPE,
1213                       "unknown type '%d' (internal fsck error)",
1214                       obj->type);
1215 }
1216
1217 int fsck_error_function(struct fsck_options *o,
1218                         const struct object_id *oid,
1219                         enum object_type object_type,
1220                         enum fsck_msg_type msg_type,
1221                         enum fsck_msg_id msg_id,
1222                         const char *message)
1223 {
1224         if (msg_type == FSCK_WARN) {
1225                 warning("object %s: %s", fsck_describe_object(o, oid), message);
1226                 return 0;
1227         }
1228         error("object %s: %s", fsck_describe_object(o, oid), message);
1229         return 1;
1230 }
1231
1232 int fsck_finish(struct fsck_options *options)
1233 {
1234         int ret = 0;
1235         struct oidset_iter iter;
1236         const struct object_id *oid;
1237
1238         oidset_iter_init(&options->gitmodules_found, &iter);
1239         while ((oid = oidset_iter_next(&iter))) {
1240                 enum object_type type;
1241                 unsigned long size;
1242                 char *buf;
1243
1244                 if (oidset_contains(&options->gitmodules_done, oid))
1245                         continue;
1246
1247                 buf = read_object_file(oid, &type, &size);
1248                 if (!buf) {
1249                         if (is_promisor_object(oid))
1250                                 continue;
1251                         ret |= report(options,
1252                                       oid, OBJ_BLOB,
1253                                       FSCK_MSG_GITMODULES_MISSING,
1254                                       "unable to read .gitmodules blob");
1255                         continue;
1256                 }
1257
1258                 if (type == OBJ_BLOB)
1259                         ret |= fsck_blob(oid, buf, size, options);
1260                 else
1261                         ret |= report(options,
1262                                       oid, type,
1263                                       FSCK_MSG_GITMODULES_BLOB,
1264                                       "non-blob found at .gitmodules");
1265                 free(buf);
1266         }
1267
1268
1269         oidset_clear(&options->gitmodules_found);
1270         oidset_clear(&options->gitmodules_done);
1271         return ret;
1272 }
1273
1274 int git_fsck_config(const char *var, const char *value, void *cb)
1275 {
1276         struct fsck_options *options = cb;
1277         if (strcmp(var, "fsck.skiplist") == 0) {
1278                 const char *path;
1279                 struct strbuf sb = STRBUF_INIT;
1280
1281                 if (git_config_pathname(&path, var, value))
1282                         return 1;
1283                 strbuf_addf(&sb, "skiplist=%s", path);
1284                 free((char *)path);
1285                 fsck_set_msg_types(options, sb.buf);
1286                 strbuf_release(&sb);
1287                 return 0;
1288         }
1289
1290         if (skip_prefix(var, "fsck.", &var)) {
1291                 fsck_set_msg_type(options, var, value);
1292                 return 0;
1293         }
1294
1295         return git_default_config(var, value, cb);
1296 }
1297
1298 /*
1299  * Custom error callbacks that are used in more than one place.
1300  */
1301
1302 int fsck_error_cb_print_missing_gitmodules(struct fsck_options *o,
1303                                            const struct object_id *oid,
1304                                            enum object_type object_type,
1305                                            enum fsck_msg_type msg_type,
1306                                            enum fsck_msg_id msg_id,
1307                                            const char *message)
1308 {
1309         if (msg_id == FSCK_MSG_GITMODULES_MISSING) {
1310                 puts(oid_to_hex(oid));
1311                 return 0;
1312         }
1313         return fsck_error_function(o, oid, object_type, msg_type, msg_id, message);
1314 }