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) 2004-2009 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 struct idlist {
  50         struct idlist *next;
  51         const char *name;
  52         id_t id, id2;
  53         uint16 flags;
  54 };
  55
  56 static struct idlist *uidlist, *uidmap;
  57 static struct idlist *gidlist, *gidmap;
  58
  59 static id_t id_parse(const char *num_str)
  60 {
  61         id_t tmp, num = 0;
  62         const char *cp = num_str;
  63
  64         while (*cp) {
  65                 if (!isDigit(cp)) {
  66                   invalid_num:
  67                         rprintf(FERROR, "Invalid ID number: %s\n", num_str);
  68                         exit_cleanup(RERR_SYNTAX);
  69                 }
  70                 tmp = num * 10 + *cp++ - '0';
  71                 if (tmp < num)
  72                         goto invalid_num;
  73                 num = tmp;
  74         }
  75
  76         return num;
  77 }
  78
  79 static struct idlist *add_to_list(struct idlist **root, id_t id, const char *name,
  80                                   id_t id2, uint16 flags)
  81 {
  82         struct idlist *node = new(struct idlist);
  83         if (!node)
  84                 out_of_memory("add_to_list");
  85         node->next = *root;
  86         node->name = name;
  87         node->id = id;
  88         node->id2 = id2;
  89         node->flags = flags;
  90         *root = node;
  91         return node;
  92 }
  93
  94 /* turn a uid into a user name */
  95 char *uid_to_user(uid_t uid)
  96 {
  97         struct passwd *pass = getpwuid(uid);
  98         if (pass)
  99                 return strdup(pass->pw_name);
 100         return NULL;
 101 }
 102
 103 /* turn a gid into a group name */
 104 char *gid_to_group(gid_t gid)
 105 {
 106         struct group *grp = getgrgid(gid);
 107         if (grp)
 108                 return strdup(grp->gr_name);
 109         return NULL;
 110 }
 111
 112 /* Parse a user name or (optionally) a number into a uid */
 113 int user_to_uid(const char *name, uid_t *uid_p, BOOL num_ok)
 114 {
 115         struct passwd *pass;
 116         if (!name || !*name)
 117                 return 0;
 118         if (num_ok && name[strspn(name, "0123456789")] == '\0') {
 119                 *uid_p = id_parse(name);
 120                 return 1;
 121         }
 122         if (!(pass = getpwnam(name)))
 123                 return 0;
 124         *uid_p = pass->pw_uid;
 125         return 1;
 126 }
 127
 128 /* Parse a group name or (optionally) a number into a gid */
 129 int group_to_gid(const char *name, gid_t *gid_p, BOOL num_ok)
 130 {
 131         struct group *grp;
 132         if (!name || !*name)
 133                 return 0;
 134         if (num_ok && name[strspn(name, "0123456789")] == '\0') {
 135                 *gid_p = id_parse(name);
 136                 return 1;
 137         }
 138         if (!(grp = getgrnam(name)))
 139                 return 0;
 140         *gid_p = grp->gr_gid;
 141         return 1;
 142 }
 143
 144 static int is_in_group(gid_t gid)
 145 {
 146 #ifdef HAVE_GETGROUPS
 147         static gid_t last_in;
 148         static int ngroups = -2, last_out = -1;
 149         static GETGROUPS_T *gidset;
 150         int n;
 151
 152         if (gid == last_in && last_out >= 0)
 153                 return last_out;
 154         if (ngroups < -1) {
 155                 if ((ngroups = getgroups(0, NULL)) < 0)
 156                         ngroups = 0;
 157                 gidset = new_array(GETGROUPS_T, ngroups+1);
 158                 if (!gidset)
 159                         out_of_memory("is_in_group");
 160                 if (ngroups > 0)
 161                         ngroups = getgroups(ngroups, gidset);
 162                 /* The default gid might not be in the list on some systems. */
 163                 for (n = 0; n < ngroups; n++) {
 164                         if (gidset[n] == our_gid)
 165                                 break;
 166                 }
 167                 if (n == ngroups)
 168                         gidset[ngroups++] = our_gid;
 169                 if (DEBUG_GTE(OWN, 2)) {
 170                         int pos;
 171                         char *gidbuf = new_array(char, ngroups*21+32);
 172                         if (!gidbuf)
 173                                 out_of_memory("is_in_group");
 174                         pos = snprintf(gidbuf, 32, "process has %d gid%s: ",
 175                                        ngroups, ngroups == 1? "" : "s");
 176                         for (n = 0; n < ngroups; n++) {
 177                                 pos += snprintf(gidbuf+pos, 21, " %d", (int)gidset[n]);
 178                         }
 179                         rprintf(FINFO, "%s\n", gidbuf);
 180                         free(gidbuf);
 181                 }
 182         }
 183
 184         last_in = gid;
 185         for (n = 0; n < ngroups; n++) {
 186                 if (gidset[n] == gid)
 187                         return last_out = 1;
 188         }
 189         return last_out = 0;
 190
 191 #else
 192         return gid == our_gid;
 193 #endif
 194 }
 195
 196 /* Add a uid/gid to its list of ids.  Only called on receiving side. */
 197 static struct idlist *recv_add_id(struct idlist **idlist_ptr, struct idlist *idmap,
 198                                   id_t id, const char *name)
 199 {
 200         struct idlist *node;
 201         int flag;
 202         id_t id2;
 203
 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->name, name))
 210                                 continue;
 211                 } else if (node->flags & NFLAGS_NAME_MATCH) {
 212                         if (strcmp(node->name, name) != 0)
 213                                 continue;
 214                 } else if (node->name) {
 215                         if (id < node->id || (unsigned long)id > (unsigned long)node->name)
 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, *name ? name : NULL, 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 definate 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
 297         if (uid == 0)   /* don't map root */
 298                 return NULL;
 299
 300         for (list = uidlist; list; list = list->next) {
 301                 if (list->id == uid)
 302                         return NULL;
 303         }
 304
 305         node = add_to_list(&uidlist, uid, uid_to_user(uid), 0, 0);
 306         return node->name;
 307 }
 308
 309 /* Add a gid to the list of gids.  Only called on sending side. */
 310 const char *add_gid(gid_t gid)
 311 {
 312         struct idlist *list;
 313         struct idlist *node;
 314
 315         if (gid == 0)   /* don't map root */
 316                 return NULL;
 317
 318         for (list = gidlist; list; list = list->next) {
 319                 if (list->id == gid)
 320                         return NULL;
 321         }
 322
 323         node = add_to_list(&gidlist, gid, gid_to_group(gid), 0, 0);
 324         return node->name;
 325 }
 326
 327 /* send a complete uid/gid mapping to the peer */
 328 void send_id_list(int f)
 329 {
 330         struct idlist *list;
 331
 332         if (preserve_uid || preserve_acls) {
 333                 int len;
 334                 /* we send sequences of uid/byte-length/name */
 335                 for (list = uidlist; list; list = list->next) {
 336                         if (!list->name)
 337                                 continue;
 338                         len = strlen(list->name);
 339                         write_varint30(f, list->id);
 340                         write_byte(f, len);
 341                         write_buf(f, list->name, len);
 342                 }
 343
 344                 /* terminate the uid list with a 0 uid. We explicitly exclude
 345                  * 0 from the list */
 346                 write_varint30(f, 0);
 347         }
 348
 349         if (preserve_gid || preserve_acls) {
 350                 int len;
 351                 for (list = gidlist; list; list = list->next) {
 352                         if (!list->name)
 353                                 continue;
 354                         len = strlen(list->name);
 355                         write_varint30(f, list->id);
 356                         write_byte(f, len);
 357                         write_buf(f, list->name, len);
 358                 }
 359                 write_varint30(f, 0);
 360         }
 361 }
 362
 363 uid_t recv_user_name(int f, uid_t uid)
 364 {
 365         struct idlist *node;
 366         int len = read_byte(f);
 367         char *name = new_array(char, len+1);
 368         if (!name)
 369                 out_of_memory("recv_user_name");
 370         read_sbuf(f, name, len);
 371         if (numeric_ids < 0) {
 372                 free(name);
 373                 name = NULL;
 374         }
 375         node = recv_add_id(&uidlist, uidmap, uid, name); /* node keeps name's memory */
 376         return node->id2;
 377 }
 378
 379 gid_t recv_group_name(int f, gid_t gid, uint16 *flags_ptr)
 380 {
 381         struct idlist *node;
 382         int len = read_byte(f);
 383         char *name = new_array(char, len+1);
 384         if (!name)
 385                 out_of_memory("recv_group_name");
 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]),
 428                                                              &flist->files[i]->flags);
 429                 }
 430         }
 431 }
 432
 433 void parse_name_map(char *map, BOOL usernames)
 434 {
 435         struct idlist **idmap_ptr = usernames ? &uidmap : &gidmap;
 436         struct idlist **idlist_ptr = usernames ? &uidlist : &gidlist;
 437         char *colon, *end, *name, *cp = map + strlen(map);
 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                 end = cp;
 444                 while (cp > map && cp[-1] != ',') cp--;
 445                 if (!(colon = strchr(cp, ':'))) {
 446                         rprintf(FERROR, "No colon found in --%smap: %s\n",
 447                                 usernames ? "user" : "group", cp);
 448                         exit_cleanup(RERR_SYNTAX);
 449                 }
 450                 if (!colon[1]) {
 451                         rprintf(FERROR, "No name found after colon --%smap: %s\n",
 452                                 usernames ? "user" : "group", cp);
 453                         exit_cleanup(RERR_SYNTAX);
 454                 }
 455                 *colon = '\0';
 456
 457                 if (isDigit(cp)) {
 458                         char *dash = strchr(cp, '-');
 459                         if (strspn(cp, "0123456789-") != (size_t)(colon - cp)
 460                          || (dash && (!dash[1] || strchr(dash+1, '-')))) {
 461                                 rprintf(FERROR, "Invalid number in --%smap: %s\n",
 462                                         usernames ? "user" : "group", cp);
 463                                 exit_cleanup(RERR_SYNTAX);
 464                         }
 465                         if (dash)
 466                                 name = (char *)id_parse(dash+1);
 467                         else
 468                                 name = (char *)0;
 469                         flags = 0;
 470                         id1 = id_parse(cp);
 471                 } else if (strpbrk(cp, "*[?")) {
 472                         flags = NFLAGS_WILD_NAME_MATCH;
 473                         name = cp;
 474                         id1 = 0;
 475                 } else {
 476                         flags = NFLAGS_NAME_MATCH;
 477                         name = cp;
 478                         id1 = 0;
 479                 }
 480
 481                 if (usernames) {
 482                         uid_t uid;
 483                         if (user_to_uid(colon+1, &uid, True))
 484                                 add_to_list(idmap_ptr, id1, name, uid, flags);
 485                         else {
 486                                 rprintf(FERROR,
 487                                     "Unknown --usermap name on receiver: %s\n",
 488                                     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, name, gid, flags);
 494                         else {
 495                                 rprintf(FERROR,
 496                                     "Unknown --groupmap name on receiver: %s\n",
 497                                     colon+1);
 498                         }
 499                 }
 500
 501                 if (cp == map)
 502                         break;
 503
 504                 *--cp = '\0'; /* replace comma */
 505         }
 506
 507         /* The 0 user/group doesn't get its name sent, so add it explicitly. */
 508         recv_add_id(idlist_ptr, *idmap_ptr, 0,
 509                     numeric_ids ? NULL : usernames ? uid_to_user(0) : gid_to_group(0));
 510 }
 511
 512 #ifdef HAVE_GETGROUPLIST
 513 const char *getallgroups(uid_t uid, gid_t *gid_list, int *size_ptr)
 514 {
 515         struct passwd *pw;
 516         if ((pw = getpwuid(uid)) == NULL)
 517                 return "getpwuid failed";
 518         /* Get all the process's groups, with the pw_gid group first. */
 519         if (getgrouplist(pw->pw_name, pw->pw_gid, gid_list, size_ptr) < 0)
 520                 return "getgrouplist failed";
 521         /* Paranoia: is the default group not first in the list? */
 522         if (gid_list[0] != pw->pw_gid) {
 523                 int j;
 524                 for (j = 0; j < *size_ptr; j++) {
 525                         if (gid_list[j] == pw->pw_gid) {
 526                                 gid_list[j] = gid_list[0];
 527                                 gid_list[0] = pw->pw_gid;
 528                                 break;
 529                         }
 530                 }
 531         }
 532         return NULL;
 533 }
 534 #endif