uidlist.c

   1 /*
   2  * Handle the mapping of uid/gid and user/group names between systems.
   3  *
   4  * Copyright (C) 1996 Andrew Tridgell
   5  * Copyright (C) 1996 Paul Mackerras
   6  * Copyright (C) 2004-2020 Wayne Davison
   7  *
   8  * This program is free software; you can redistribute it and/or modify
   9  * it under the terms of the GNU General Public License as published by
  10  * the Free Software Foundation; either version 3 of the License, or
  11  * (at your option) any later version.
  12  *
  13  * This program is distributed in the hope that it will be useful,
  14  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16  * GNU General Public License for more details.
  17  *
  18  * You should have received a copy of the GNU General Public License along
  19  * with this program; if not, visit the http://fsf.org website.
  20  */
  21
  22 /* If the source username/group does not exist on the target then use
  23  * the numeric IDs.  Never do any mapping for uid=0 or gid=0 as these
  24  * are special. */
  25
  26 #include "rsync.h"
  27 #include "ifuncs.h"
  28 #include "itypes.h"
  29 #include "io.h"
  30
  31 extern int am_root;
  32 extern int preserve_uid;
  33 extern int preserve_gid;
  34 extern int preserve_acls;
  35 extern int numeric_ids;
  36 extern gid_t our_gid;
  37 extern char *usermap;
  38 extern char *groupmap;
  39
  40 #ifdef HAVE_GETGROUPS
  41 # ifndef GETGROUPS_T
  42 #  define GETGROUPS_T gid_t
  43 # endif
  44 #endif
  45
  46 #define NFLAGS_WILD_NAME_MATCH (1<<0)
  47 #define NFLAGS_NAME_MATCH (1<<1)
  48
  49 union name_or_id {
  50         const char *name;
  51         id_t max_id;
  52 };
  53
  54 struct idlist {
  55         struct idlist *next;
  56         union name_or_id u;
  57         id_t id, id2;
  58         uint16 flags;
  59 };
  60
  61 static struct idlist *uidlist, *uidmap;
  62 static struct idlist *gidlist, *gidmap;
  63
  64 static id_t id_parse(const char *num_str)
  65 {
  66         id_t tmp, num = 0;
  67         const char *cp = num_str;
  68
  69         while (*cp) {
  70                 if (!isDigit(cp)) {
  71                   invalid_num:
  72                         rprintf(FERROR, "Invalid ID number: %s\n", num_str);
  73                         exit_cleanup(RERR_SYNTAX);
  74                 }
  75                 tmp = num * 10 + *cp++ - '0';
  76                 if (tmp < num)
  77                         goto invalid_num;
  78                 num = tmp;
  79         }
  80
  81         return num;
  82 }
  83
  84 static struct idlist *add_to_list(struct idlist **root, id_t id, union name_or_id noiu,
  85                                   id_t id2, uint16 flags)
  86 {
  87         struct idlist *node = new(struct idlist);
  88         if (!node)
  89                 out_of_memory("add_to_list");
  90         node->next = *root;
  91         node->u = noiu;
  92         node->id = id;
  93         node->id2 = id2;
  94         node->flags = flags;
  95         *root = node;
  96         return node;
  97 }
  98
  99 /* turn a uid into a user name */
 100 char *uid_to_user(uid_t uid)
 101 {
 102         struct passwd *pass = getpwuid(uid);
 103         if (pass)
 104                 return strdup(pass->pw_name);
 105         return NULL;
 106 }
 107
 108 /* turn a gid into a group name */
 109 char *gid_to_group(gid_t gid)
 110 {
 111         struct group *grp = getgrgid(gid);
 112         if (grp)
 113                 return strdup(grp->gr_name);
 114         return NULL;
 115 }
 116
 117 /* Parse a user name or (optionally) a number into a uid */
 118 int user_to_uid(const char *name, uid_t *uid_p, BOOL num_ok)
 119 {
 120         struct passwd *pass;
 121         if (!name || !*name)
 122                 return 0;
 123         if (num_ok && name[strspn(name, "0123456789")] == '\0') {
 124                 *uid_p = id_parse(name);
 125                 return 1;
 126         }
 127         if (!(pass = getpwnam(name)))
 128                 return 0;
 129         *uid_p = pass->pw_uid;
 130         return 1;
 131 }
 132
 133 /* Parse a group name or (optionally) a number into a gid */
 134 int group_to_gid(const char *name, gid_t *gid_p, BOOL num_ok)
 135 {
 136         struct group *grp;
 137         if (!name || !*name)
 138                 return 0;
 139         if (num_ok && name[strspn(name, "0123456789")] == '\0') {
 140                 *gid_p = id_parse(name);
 141                 return 1;
 142         }
 143         if (!(grp = getgrnam(name)))
 144                 return 0;
 145         *gid_p = grp->gr_gid;
 146         return 1;
 147 }
 148
 149 static int is_in_group(gid_t gid)
 150 {
 151 #ifdef HAVE_GETGROUPS
 152         static gid_t last_in;
 153         static int ngroups = -2, last_out = -1;
 154         static GETGROUPS_T *gidset;
 155         int n;
 156
 157         if (gid == last_in && last_out >= 0)
 158                 return last_out;
 159         if (ngroups < -1) {
 160                 if ((ngroups = getgroups(0, NULL)) < 0)
 161                         ngroups = 0;
 162                 gidset = new_array(GETGROUPS_T, ngroups+1);
 163                 if (!gidset)
 164                         out_of_memory("is_in_group");
 165                 if (ngroups > 0)
 166                         ngroups = getgroups(ngroups, gidset);
 167                 /* The default gid might not be in the list on some systems. */
 168                 for (n = 0; n < ngroups; n++) {
 169                         if (gidset[n] == our_gid)
 170                                 break;
 171                 }
 172                 if (n == ngroups)
 173                         gidset[ngroups++] = our_gid;
 174                 if (DEBUG_GTE(OWN, 2)) {
 175                         int pos;
 176                         char *gidbuf = new_array(char, ngroups*21+32);
 177                         if (!gidbuf)
 178                                 out_of_memory("is_in_group");
 179                         pos = snprintf(gidbuf, 32, "process has %d gid%s: ", ngroups, ngroups == 1? "" : "s");
 180                         for (n = 0; n < ngroups; n++) {
 181                                 pos += snprintf(gidbuf+pos, 21, " %d", (int)gidset[n]);
 182                         }
 183                         rprintf(FINFO, "%s\n", gidbuf);
 184                         free(gidbuf);
 185                 }
 186         }
 187
 188         last_in = gid;
 189         for (n = 0; n < ngroups; n++) {
 190                 if (gidset[n] == gid)
 191                         return last_out = 1;
 192         }
 193         return last_out = 0;
 194
 195 #else
 196         return gid == our_gid;
 197 #endif
 198 }
 199
 200 /* Add a uid/gid to its list of ids.  Only called on receiving side. */
 201 static struct idlist *recv_add_id(struct idlist **idlist_ptr, struct idlist *idmap,
 202                                   id_t id, const char *name)
 203 {
 204         struct idlist *node;
 205         union name_or_id noiu;
 206         int flag;
 207         id_t id2;
 208
 209         noiu.name = name; /* ensure that add_to_list() gets the raw value. */
 210         if (!name)
 211                 name = "";
 212
 213         for (node = idmap; node; node = node->next) {
 214                 if (node->flags & NFLAGS_WILD_NAME_MATCH) {
 215                         if (!wildmatch(node->u.name, name))
 216                                 continue;
 217                 } else if (node->flags & NFLAGS_NAME_MATCH) {
 218                         if (strcmp(node->u.name, name) != 0)
 219                                 continue;
 220                 } else if (node->u.max_id) {
 221                         if (id < node->id || id > node->u.max_id)
 222                                 continue;
 223                 } else {
 224                         if (node->id != id)
 225                                 continue;
 226                 }
 227                 break;
 228         }
 229         if (node)
 230                 id2 = node->id2;
 231         else if (*name && id) {
 232                 if (idlist_ptr == &uidlist) {
 233                         uid_t uid;
 234                         id2 = user_to_uid(name, &uid, False) ? uid : id;
 235                 } else {
 236                         gid_t gid;
 237                         id2 = group_to_gid(name, &gid, False) ? gid : id;
 238                 }
 239         } else
 240                 id2 = id;
 241
 242         flag = idlist_ptr == &gidlist && !am_root && !is_in_group(id2) ? FLAG_SKIP_GROUP : 0;
 243         node = add_to_list(idlist_ptr, id, noiu, id2, flag);
 244
 245         if (DEBUG_GTE(OWN, 2)) {
 246                 rprintf(FINFO, "%sid %u(%s) maps to %u\n",
 247                         idlist_ptr == &uidlist ? "u" : "g",
 248                         (unsigned)id, name, (unsigned)id2);
 249         }
 250
 251         return node;
 252 }
 253
 254 /* this function is a definite candidate for a faster algorithm */
 255 uid_t match_uid(uid_t uid)
 256 {
 257         static struct idlist *last = NULL;
 258         struct idlist *list;
 259
 260         if (last && uid == last->id)
 261                 return last->id2;
 262
 263         for (list = uidlist; list; list = list->next) {
 264                 if (list->id == uid)
 265                         break;
 266         }
 267
 268         if (!list)
 269                 list = recv_add_id(&uidlist, uidmap, uid, NULL);
 270         last = list;
 271
 272         return list->id2;
 273 }
 274
 275 gid_t match_gid(gid_t gid, uint16 *flags_ptr)
 276 {
 277         static struct idlist *last = NULL;
 278         struct idlist *list;
 279
 280         if (last && gid == last->id)
 281                 list = last;
 282         else {
 283                 for (list = gidlist; list; list = list->next) {
 284                         if (list->id == gid)
 285                                 break;
 286                 }
 287                 if (!list)
 288                         list = recv_add_id(&gidlist, gidmap, gid, NULL);
 289                 last = list;
 290         }
 291
 292         if (flags_ptr && list->flags & FLAG_SKIP_GROUP)
 293                 *flags_ptr |= FLAG_SKIP_GROUP;
 294         return list->id2;
 295 }
 296
 297 /* Add a uid to the list of uids.  Only called on sending side. */
 298 const char *add_uid(uid_t uid)
 299 {
 300         struct idlist *list;
 301         struct idlist *node;
 302         union name_or_id noiu;
 303
 304         if (uid == 0)   /* don't map root */
 305                 return NULL;
 306
 307         for (list = uidlist; list; list = list->next) {
 308                 if (list->id == uid)
 309                         return NULL;
 310         }
 311
 312         noiu.name = uid_to_user(uid);
 313         node = add_to_list(&uidlist, uid, noiu, 0, 0);
 314         return node->u.name;
 315 }
 316
 317 /* Add a gid to the list of gids.  Only called on sending side. */
 318 const char *add_gid(gid_t gid)
 319 {
 320         struct idlist *list;
 321         struct idlist *node;
 322         union name_or_id noiu;
 323
 324         if (gid == 0)   /* don't map root */
 325                 return NULL;
 326
 327         for (list = gidlist; list; list = list->next) {
 328                 if (list->id == gid)
 329                         return NULL;
 330         }
 331
 332         noiu.name = gid_to_group(gid);
 333         node = add_to_list(&gidlist, gid, noiu, 0, 0);
 334         return node->u.name;
 335 }
 336
 337 /* send a complete uid/gid mapping to the peer */
 338 void send_id_list(int f)
 339 {
 340         struct idlist *list;
 341
 342         if (preserve_uid || preserve_acls) {
 343                 int len;
 344                 /* we send sequences of uid/byte-length/name */
 345                 for (list = uidlist; list; list = list->next) {
 346                         if (!list->u.name)
 347                                 continue;
 348                         len = strlen(list->u.name);
 349                         write_varint30(f, list->id);
 350                         write_byte(f, len);
 351                         write_buf(f, list->u.name, len);
 352                 }
 353
 354                 /* terminate the uid list with a 0 uid. We explicitly exclude
 355                  * 0 from the list */
 356                 write_varint30(f, 0);
 357         }
 358
 359         if (preserve_gid || preserve_acls) {
 360                 int len;
 361                 for (list = gidlist; list; list = list->next) {
 362                         if (!list->u.name)
 363                                 continue;
 364                         len = strlen(list->u.name);
 365                         write_varint30(f, list->id);
 366                         write_byte(f, len);
 367                         write_buf(f, list->u.name, len);
 368                 }
 369                 write_varint30(f, 0);
 370         }
 371 }
 372
 373 uid_t recv_user_name(int f, uid_t uid)
 374 {
 375         struct idlist *node;
 376         int len = read_byte(f);
 377         char *name = new_array(char, len+1);
 378         if (!name)
 379                 out_of_memory("recv_user_name");
 380         read_sbuf(f, name, len);
 381         if (numeric_ids < 0) {
 382                 free(name);
 383                 name = NULL;
 384         }
 385         node = recv_add_id(&uidlist, uidmap, uid, name); /* node keeps name's memory */
 386         return node->id2;
 387 }
 388
 389 gid_t recv_group_name(int f, gid_t gid, uint16 *flags_ptr)
 390 {
 391         struct idlist *node;
 392         int len = read_byte(f);
 393         char *name = new_array(char, len+1);
 394         if (!name)
 395                 out_of_memory("recv_group_name");
 396         read_sbuf(f, name, len);
 397         if (numeric_ids < 0) {
 398                 free(name);
 399                 name = NULL;
 400         }
 401         node = recv_add_id(&gidlist, gidmap, gid, name); /* node keeps name's memory */
 402         if (flags_ptr && node->flags & FLAG_SKIP_GROUP)
 403                 *flags_ptr |= FLAG_SKIP_GROUP;
 404         return node->id2;
 405 }
 406
 407 /* recv a complete uid/gid mapping from the peer and map the uid/gid
 408  * in the file list to local names */
 409 void recv_id_list(int f, struct file_list *flist)
 410 {
 411         id_t id;
 412         int i;
 413
 414         if ((preserve_uid || preserve_acls) && numeric_ids <= 0) {
 415                 /* read the uid list */
 416                 while ((id = read_varint30(f)) != 0)
 417                         recv_user_name(f, id);
 418         }
 419
 420         if ((preserve_gid || preserve_acls) && numeric_ids <= 0) {
 421                 /* read the gid list */
 422                 while ((id = read_varint30(f)) != 0)
 423                         recv_group_name(f, id, NULL);
 424         }
 425
 426         /* Now convert all the uids/gids from sender values to our values. */
 427 #ifdef SUPPORT_ACLS
 428         if (preserve_acls && (!numeric_ids || usermap || groupmap))
 429                 match_acl_ids();
 430 #endif
 431         if (am_root && preserve_uid && (!numeric_ids || usermap)) {
 432                 for (i = 0; i < flist->used; i++)
 433                         F_OWNER(flist->files[i]) = match_uid(F_OWNER(flist->files[i]));
 434         }
 435         if (preserve_gid && (!am_root || !numeric_ids || groupmap)) {
 436                 for (i = 0; i < flist->used; i++) {
 437                         F_GROUP(flist->files[i]) = match_gid(F_GROUP(flist->files[i]), &flist->files[i]->flags);
 438                 }
 439         }
 440 }
 441
 442 void parse_name_map(char *map, BOOL usernames)
 443 {
 444         struct idlist **idmap_ptr = usernames ? &uidmap : &gidmap;
 445         struct idlist **idlist_ptr = usernames ? &uidlist : &gidlist;
 446         char *colon, *cp = map + strlen(map);
 447         union name_or_id noiu;
 448         id_t id1;
 449         uint16 flags;
 450
 451         /* Parse the list in reverse, so the order in the struct is right. */
 452         while (1) {
 453                 while (cp > map && cp[-1] != ',') cp--;
 454                 if (!(colon = strchr(cp, ':'))) {
 455                         rprintf(FERROR, "No colon found in --%smap: %s\n",
 456                                 usernames ? "user" : "group", cp);
 457                         exit_cleanup(RERR_SYNTAX);
 458                 }
 459                 if (!colon[1]) {
 460                         rprintf(FERROR, "No name found after colon --%smap: %s\n",
 461                                 usernames ? "user" : "group", cp);
 462                         exit_cleanup(RERR_SYNTAX);
 463                 }
 464                 *colon = '\0';
 465
 466                 if (isDigit(cp)) {
 467                         char *dash = strchr(cp, '-');
 468                         if (strspn(cp, "0123456789-") != (size_t)(colon - cp)
 469                          || (dash && (!dash[1] || strchr(dash+1, '-')))) {
 470                                 rprintf(FERROR, "Invalid number in --%smap: %s\n",
 471                                         usernames ? "user" : "group", cp);
 472                                 exit_cleanup(RERR_SYNTAX);
 473                         }
 474                         if (dash) {
 475                                 *dash = '\0';
 476                                 noiu.max_id = id_parse(dash+1);
 477                         } else
 478                                 noiu.max_id = 0;
 479                         flags = 0;
 480                         id1 = id_parse(cp);
 481                         if (dash)
 482                                 *dash = '-';
 483                 } else if (strpbrk(cp, "*[?")) {
 484                         flags = NFLAGS_WILD_NAME_MATCH;
 485                         noiu.name = cp;
 486                         id1 = 0;
 487                 } else {
 488                         flags = NFLAGS_NAME_MATCH;
 489                         noiu.name = cp;
 490                         id1 = 0;
 491                 }
 492
 493                 if (usernames) {
 494                         uid_t uid;
 495                         if (user_to_uid(colon+1, &uid, True))
 496                                 add_to_list(idmap_ptr, id1, noiu, uid, flags);
 497                         else {
 498                                 rprintf(FERROR, "Unknown --usermap name on receiver: %s\n", colon+1);
 499                         }
 500                 } else {
 501                         gid_t gid;
 502                         if (group_to_gid(colon+1, &gid, True))
 503                                 add_to_list(idmap_ptr, id1, noiu, gid, flags);
 504                         else {
 505                                 rprintf(FERROR, "Unknown --groupmap name on receiver: %s\n", colon+1);
 506                         }
 507                 }
 508
 509                 if (cp == map)
 510                         break;
 511
 512                 *--cp = '\0'; /* replace comma */
 513         }
 514
 515         /* The 0 user/group doesn't get its name sent, so add it explicitly. */
 516         recv_add_id(idlist_ptr, *idmap_ptr, 0, numeric_ids ? NULL : usernames ? uid_to_user(0) : gid_to_group(0));
 517 }
 518
 519 #ifdef HAVE_GETGROUPLIST
 520 const char *getallgroups(uid_t uid, item_list *gid_list)
 521 {
 522         struct passwd *pw;
 523         gid_t *gid_array;
 524         int size;
 525
 526         if ((pw = getpwuid(uid)) == NULL)
 527                 return "getpwuid failed";
 528
 529         gid_list->count = 0; /* We're overwriting any items in the list */
 530         (void)EXPAND_ITEM_LIST(gid_list, gid_t, 32);
 531         size = gid_list->malloced;
 532
 533         /* Get all the process's groups, with the pw_gid group first. */
 534         if (getgrouplist(pw->pw_name, pw->pw_gid, gid_list->items, &size) < 0) {
 535                 if (size > (int)gid_list->malloced) {
 536                         gid_list->count = gid_list->malloced;
 537                         (void)EXPAND_ITEM_LIST(gid_list, gid_t, size);
 538                         if (getgrouplist(pw->pw_name, pw->pw_gid, gid_list->items, &size) < 0)
 539                                 size = -1;
 540                 } else
 541                         size = -1;
 542                 if (size < 0)
 543                         return "getgrouplist failed";
 544         }
 545         gid_list->count = size;
 546         gid_array = gid_list->items;
 547
 548         /* Paranoia: is the default group not first in the list? */
 549         if (gid_array[0] != pw->pw_gid) {
 550                 int j;
 551                 for (j = 1; j < size; j++) {
 552                         if (gid_array[j] == pw->pw_gid)
 553                                 break;
 554                 }
 555                 if (j == size) { /* The default group wasn't found! */
 556                         (void)EXPAND_ITEM_LIST(gid_list, gid_t, size+1);
 557                         gid_array = gid_list->items;
 558                 }
 559                 gid_array[j] = gid_array[0];
 560                 gid_array[0] = pw->pw_gid;
 561         }
 562
 563         return NULL;
 564 }
 565 #endif