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         node->next = *root;
  89         node->u = noiu;
  90         node->id = id;
  91         node->id2 = id2;
  92         node->flags = flags;
  93         *root = node;
  94         return node;
  95 }
  96
  97 /* turn a uid into a user name */
  98 char *uid_to_user(uid_t uid)
  99 {
 100         struct passwd *pass = getpwuid(uid);
 101         if (pass)
 102                 return strdup(pass->pw_name);
 103         return NULL;
 104 }
 105
 106 /* turn a gid into a group name */
 107 char *gid_to_group(gid_t gid)
 108 {
 109         struct group *grp = getgrgid(gid);
 110         if (grp)
 111                 return strdup(grp->gr_name);
 112         return NULL;
 113 }
 114
 115 /* Parse a user name or (optionally) a number into a uid */
 116 int user_to_uid(const char *name, uid_t *uid_p, BOOL num_ok)
 117 {
 118         struct passwd *pass;
 119         if (!name || !*name)
 120                 return 0;
 121         if (num_ok && name[strspn(name, "0123456789")] == '\0') {
 122                 *uid_p = id_parse(name);
 123                 return 1;
 124         }
 125         if (!(pass = getpwnam(name)))
 126                 return 0;
 127         *uid_p = pass->pw_uid;
 128         return 1;
 129 }
 130
 131 /* Parse a group name or (optionally) a number into a gid */
 132 int group_to_gid(const char *name, gid_t *gid_p, BOOL num_ok)
 133 {
 134         struct group *grp;
 135         if (!name || !*name)
 136                 return 0;
 137         if (num_ok && name[strspn(name, "0123456789")] == '\0') {
 138                 *gid_p = id_parse(name);
 139                 return 1;
 140         }
 141         if (!(grp = getgrnam(name)))
 142                 return 0;
 143         *gid_p = grp->gr_gid;
 144         return 1;
 145 }
 146
 147 static int is_in_group(gid_t gid)
 148 {
 149 #ifdef HAVE_GETGROUPS
 150         static gid_t last_in;
 151         static int ngroups = -2, last_out = -1;
 152         static GETGROUPS_T *gidset;
 153         int n;
 154
 155         if (gid == last_in && last_out >= 0)
 156                 return last_out;
 157         if (ngroups < -1) {
 158                 if ((ngroups = getgroups(0, NULL)) < 0)
 159                         ngroups = 0;
 160                 gidset = new_array(GETGROUPS_T, ngroups+1);
 161                 if (ngroups > 0)
 162                         ngroups = getgroups(ngroups, gidset);
 163                 /* The default gid might not be in the list on some systems. */
 164                 for (n = 0; n < ngroups; n++) {
 165                         if (gidset[n] == our_gid)
 166                                 break;
 167                 }
 168                 if (n == ngroups)
 169                         gidset[ngroups++] = our_gid;
 170                 if (DEBUG_GTE(OWN, 2)) {
 171                         int pos;
 172                         char *gidbuf = new_array(char, ngroups*21+32);
 173                         pos = snprintf(gidbuf, 32, "process has %d gid%s: ", ngroups, ngroups == 1? "" : "s");
 174                         for (n = 0; n < ngroups; n++) {
 175                                 pos += snprintf(gidbuf+pos, 21, " %d", (int)gidset[n]);
 176                         }
 177                         rprintf(FINFO, "%s\n", gidbuf);
 178                         free(gidbuf);
 179                 }
 180         }
 181
 182         last_in = gid;
 183         for (n = 0; n < ngroups; n++) {
 184                 if (gidset[n] == gid)
 185                         return last_out = 1;
 186         }
 187         return last_out = 0;
 188
 189 #else
 190         return gid == our_gid;
 191 #endif
 192 }
 193
 194 /* Add a uid/gid to its list of ids.  Only called on receiving side. */
 195 static struct idlist *recv_add_id(struct idlist **idlist_ptr, struct idlist *idmap,
 196                                   id_t id, const char *name)
 197 {
 198         struct idlist *node;
 199         union name_or_id noiu;
 200         int flag;
 201         id_t id2;
 202
 203         noiu.name = name; /* ensure that add_to_list() gets the raw value. */
 204         if (!name)
 205                 name = "";
 206
 207         for (node = idmap; node; node = node->next) {
 208                 if (node->flags & NFLAGS_WILD_NAME_MATCH) {
 209                         if (!wildmatch(node->u.name, name))
 210                                 continue;
 211                 } else if (node->flags & NFLAGS_NAME_MATCH) {
 212                         if (strcmp(node->u.name, name) != 0)
 213                                 continue;
 214                 } else if (node->u.max_id) {
 215                         if (id < node->id || id > node->u.max_id)
 216                                 continue;
 217                 } else {
 218                         if (node->id != id)
 219                                 continue;
 220                 }
 221                 break;
 222         }
 223         if (node)
 224                 id2 = node->id2;
 225         else if (*name && id) {
 226                 if (idlist_ptr == &uidlist) {
 227                         uid_t uid;
 228                         id2 = user_to_uid(name, &uid, False) ? uid : id;
 229                 } else {
 230                         gid_t gid;
 231                         id2 = group_to_gid(name, &gid, False) ? gid : id;
 232                 }
 233         } else
 234                 id2 = id;
 235
 236         flag = idlist_ptr == &gidlist && !am_root && !is_in_group(id2) ? FLAG_SKIP_GROUP : 0;
 237         node = add_to_list(idlist_ptr, id, noiu, id2, flag);
 238
 239         if (DEBUG_GTE(OWN, 2)) {
 240                 rprintf(FINFO, "%sid %u(%s) maps to %u\n",
 241                         idlist_ptr == &uidlist ? "u" : "g",
 242                         (unsigned)id, name, (unsigned)id2);
 243         }
 244
 245         return node;
 246 }
 247
 248 /* this function is a definite candidate for a faster algorithm */
 249 uid_t match_uid(uid_t uid)
 250 {
 251         static struct idlist *last = NULL;
 252         struct idlist *list;
 253
 254         if (last && uid == last->id)
 255                 return last->id2;
 256
 257         for (list = uidlist; list; list = list->next) {
 258                 if (list->id == uid)
 259                         break;
 260         }
 261
 262         if (!list)
 263                 list = recv_add_id(&uidlist, uidmap, uid, NULL);
 264         last = list;
 265
 266         return list->id2;
 267 }
 268
 269 gid_t match_gid(gid_t gid, uint16 *flags_ptr)
 270 {
 271         static struct idlist *last = NULL;
 272         struct idlist *list;
 273
 274         if (last && gid == last->id)
 275                 list = last;
 276         else {
 277                 for (list = gidlist; list; list = list->next) {
 278                         if (list->id == gid)
 279                                 break;
 280                 }
 281                 if (!list)
 282                         list = recv_add_id(&gidlist, gidmap, gid, NULL);
 283                 last = list;
 284         }
 285
 286         if (flags_ptr && list->flags & FLAG_SKIP_GROUP)
 287                 *flags_ptr |= FLAG_SKIP_GROUP;
 288         return list->id2;
 289 }
 290
 291 /* Add a uid to the list of uids.  Only called on sending side. */
 292 const char *add_uid(uid_t uid)
 293 {
 294         struct idlist *list;
 295         struct idlist *node;
 296         union name_or_id noiu;
 297
 298         if (uid == 0)   /* don't map root */
 299                 return NULL;
 300
 301         for (list = uidlist; list; list = list->next) {
 302                 if (list->id == uid)
 303                         return NULL;
 304         }
 305
 306         noiu.name = uid_to_user(uid);
 307         node = add_to_list(&uidlist, uid, noiu, 0, 0);
 308         return node->u.name;
 309 }
 310
 311 /* Add a gid to the list of gids.  Only called on sending side. */
 312 const char *add_gid(gid_t gid)
 313 {
 314         struct idlist *list;
 315         struct idlist *node;
 316         union name_or_id noiu;
 317
 318         if (gid == 0)   /* don't map root */
 319                 return NULL;
 320
 321         for (list = gidlist; list; list = list->next) {
 322                 if (list->id == gid)
 323                         return NULL;
 324         }
 325
 326         noiu.name = gid_to_group(gid);
 327         node = add_to_list(&gidlist, gid, noiu, 0, 0);
 328         return node->u.name;
 329 }
 330
 331 /* send a complete uid/gid mapping to the peer */
 332 void send_id_list(int f)
 333 {
 334         struct idlist *list;
 335
 336         if (preserve_uid || preserve_acls) {
 337                 int len;
 338                 /* we send sequences of uid/byte-length/name */
 339                 for (list = uidlist; list; list = list->next) {
 340                         if (!list->u.name)
 341                                 continue;
 342                         len = strlen(list->u.name);
 343                         write_varint30(f, list->id);
 344                         write_byte(f, len);
 345                         write_buf(f, list->u.name, len);
 346                 }
 347
 348                 /* terminate the uid list with a 0 uid. We explicitly exclude
 349                  * 0 from the list */
 350                 write_varint30(f, 0);
 351         }
 352
 353         if (preserve_gid || preserve_acls) {
 354                 int len;
 355                 for (list = gidlist; list; list = list->next) {
 356                         if (!list->u.name)
 357                                 continue;
 358                         len = strlen(list->u.name);
 359                         write_varint30(f, list->id);
 360                         write_byte(f, len);
 361                         write_buf(f, list->u.name, len);
 362                 }
 363                 write_varint30(f, 0);
 364         }
 365 }
 366
 367 uid_t recv_user_name(int f, uid_t uid)
 368 {
 369         struct idlist *node;
 370         int len = read_byte(f);
 371         char *name = new_array(char, len+1);
 372         read_sbuf(f, name, len);
 373         if (numeric_ids < 0) {
 374                 free(name);
 375                 name = NULL;
 376         }
 377         node = recv_add_id(&uidlist, uidmap, uid, name); /* node keeps name's memory */
 378         return node->id2;
 379 }
 380
 381 gid_t recv_group_name(int f, gid_t gid, uint16 *flags_ptr)
 382 {
 383         struct idlist *node;
 384         int len = read_byte(f);
 385         char *name = new_array(char, len+1);
 386         read_sbuf(f, name, len);
 387         if (numeric_ids < 0) {
 388                 free(name);
 389                 name = NULL;
 390         }
 391         node = recv_add_id(&gidlist, gidmap, gid, name); /* node keeps name's memory */
 392         if (flags_ptr && node->flags & FLAG_SKIP_GROUP)
 393                 *flags_ptr |= FLAG_SKIP_GROUP;
 394         return node->id2;
 395 }
 396
 397 /* recv a complete uid/gid mapping from the peer and map the uid/gid
 398  * in the file list to local names */
 399 void recv_id_list(int f, struct file_list *flist)
 400 {
 401         id_t id;
 402         int i;
 403
 404         if ((preserve_uid || preserve_acls) && numeric_ids <= 0) {
 405                 /* read the uid list */
 406                 while ((id = read_varint30(f)) != 0)
 407                         recv_user_name(f, id);
 408         }
 409
 410         if ((preserve_gid || preserve_acls) && numeric_ids <= 0) {
 411                 /* read the gid list */
 412                 while ((id = read_varint30(f)) != 0)
 413                         recv_group_name(f, id, NULL);
 414         }
 415
 416         /* Now convert all the uids/gids from sender values to our values. */
 417 #ifdef SUPPORT_ACLS
 418         if (preserve_acls && (!numeric_ids || usermap || groupmap))
 419                 match_acl_ids();
 420 #endif
 421         if (am_root && preserve_uid && (!numeric_ids || usermap)) {
 422                 for (i = 0; i < flist->used; i++)
 423                         F_OWNER(flist->files[i]) = match_uid(F_OWNER(flist->files[i]));
 424         }
 425         if (preserve_gid && (!am_root || !numeric_ids || groupmap)) {
 426                 for (i = 0; i < flist->used; i++) {
 427                         F_GROUP(flist->files[i]) = match_gid(F_GROUP(flist->files[i]), &flist->files[i]->flags);
 428                 }
 429         }
 430 }
 431
 432 void parse_name_map(char *map, BOOL usernames)
 433 {
 434         struct idlist **idmap_ptr = usernames ? &uidmap : &gidmap;
 435         struct idlist **idlist_ptr = usernames ? &uidlist : &gidlist;
 436         char *colon, *cp = map + strlen(map);
 437         union name_or_id noiu;
 438         id_t id1;
 439         uint16 flags;
 440
 441         /* Parse the list in reverse, so the order in the struct is right. */
 442         while (1) {
 443                 while (cp > map && cp[-1] != ',') cp--;
 444                 if (!(colon = strchr(cp, ':'))) {
 445                         rprintf(FERROR, "No colon found in --%smap: %s\n",
 446                                 usernames ? "user" : "group", cp);
 447                         exit_cleanup(RERR_SYNTAX);
 448                 }
 449                 if (!colon[1]) {
 450                         rprintf(FERROR, "No name found after colon --%smap: %s\n",
 451                                 usernames ? "user" : "group", cp);
 452                         exit_cleanup(RERR_SYNTAX);
 453                 }
 454                 *colon = '\0';
 455
 456                 if (isDigit(cp)) {
 457                         char *dash = strchr(cp, '-');
 458                         if (strspn(cp, "0123456789-") != (size_t)(colon - cp)
 459                          || (dash && (!dash[1] || strchr(dash+1, '-')))) {
 460                                 rprintf(FERROR, "Invalid number in --%smap: %s\n",
 461                                         usernames ? "user" : "group", cp);
 462                                 exit_cleanup(RERR_SYNTAX);
 463                         }
 464                         if (dash) {
 465                                 *dash = '\0';
 466                                 noiu.max_id = id_parse(dash+1);
 467                         } else
 468                                 noiu.max_id = 0;
 469                         flags = 0;
 470                         id1 = id_parse(cp);
 471                         if (dash)
 472                                 *dash = '-';
 473                 } else if (strpbrk(cp, "*[?")) {
 474                         flags = NFLAGS_WILD_NAME_MATCH;
 475                         noiu.name = cp;
 476                         id1 = 0;
 477                 } else {
 478                         flags = NFLAGS_NAME_MATCH;
 479                         noiu.name = cp;
 480                         id1 = 0;
 481                 }
 482
 483                 if (usernames) {
 484                         uid_t uid;
 485                         if (user_to_uid(colon+1, &uid, True))
 486                                 add_to_list(idmap_ptr, id1, noiu, uid, flags);
 487                         else {
 488                                 rprintf(FERROR, "Unknown --usermap name on receiver: %s\n", colon+1);
 489                         }
 490                 } else {
 491                         gid_t gid;
 492                         if (group_to_gid(colon+1, &gid, True))
 493                                 add_to_list(idmap_ptr, id1, noiu, gid, flags);
 494                         else {
 495                                 rprintf(FERROR, "Unknown --groupmap name on receiver: %s\n", colon+1);
 496                         }
 497                 }
 498
 499                 if (cp == map)
 500                         break;
 501
 502                 *--cp = '\0'; /* replace comma */
 503         }
 504
 505         /* The 0 user/group doesn't get its name sent, so add it explicitly. */
 506         recv_add_id(idlist_ptr, *idmap_ptr, 0, numeric_ids ? NULL : usernames ? uid_to_user(0) : gid_to_group(0));
 507 }
 508
 509 #ifdef HAVE_GETGROUPLIST
 510 const char *getallgroups(uid_t uid, item_list *gid_list)
 511 {
 512         struct passwd *pw;
 513         gid_t *gid_array;
 514         int size;
 515
 516         if ((pw = getpwuid(uid)) == NULL)
 517                 return "getpwuid failed";
 518
 519         gid_list->count = 0; /* We're overwriting any items in the list */
 520         (void)EXPAND_ITEM_LIST(gid_list, gid_t, 32);
 521         size = gid_list->malloced;
 522
 523         /* Get all the process's groups, with the pw_gid group first. */
 524         if (getgrouplist(pw->pw_name, pw->pw_gid, gid_list->items, &size) < 0) {
 525                 if (size > (int)gid_list->malloced) {
 526                         gid_list->count = gid_list->malloced;
 527                         (void)EXPAND_ITEM_LIST(gid_list, gid_t, size);
 528                         if (getgrouplist(pw->pw_name, pw->pw_gid, gid_list->items, &size) < 0)
 529                                 size = -1;
 530                 } else
 531                         size = -1;
 532                 if (size < 0)
 533                         return "getgrouplist failed";
 534         }
 535         gid_list->count = size;
 536         gid_array = gid_list->items;
 537
 538         /* Paranoia: is the default group not first in the list? */
 539         if (gid_array[0] != pw->pw_gid) {
 540                 int j;
 541                 for (j = 1; j < size; j++) {
 542                         if (gid_array[j] == pw->pw_gid)
 543                                 break;
 544                 }
 545                 if (j == size) { /* The default group wasn't found! */
 546                         (void)EXPAND_ITEM_LIST(gid_list, gid_t, size+1);
 547                         gid_array = gid_list->items;
 548                 }
 549                 gid_array[j] = gid_array[0];
 550                 gid_array[0] = pw->pw_gid;
 551         }
 552
 553         return NULL;
 554 }
 555 #endif