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 int xmit_id0_names;
37: extern pid_t namecvt_pid;
38: extern gid_t our_gid;
39: extern char *usermap;
40: extern char *groupmap;
41:
42: #ifdef HAVE_GETGROUPS
43: # ifndef GETGROUPS_T
44: # define GETGROUPS_T gid_t
45: # endif
46: #endif
47:
48: #define NFLAGS_WILD_NAME_MATCH (1<<0)
49: #define NFLAGS_NAME_MATCH (1<<1)
50:
51: union name_or_id {
52: const char *name;
53: id_t max_id;
54: };
55:
56: struct idlist {
57: struct idlist *next;
58: union name_or_id u;
59: id_t id, id2;
60: uint16 flags;
61: };
62:
63: static struct idlist *uidlist, *uidmap;
64: static struct idlist *gidlist, *gidmap;
65:
66: static id_t id_parse(const char *num_str)
67: {
68: id_t tmp, num = 0;
69: const char *cp = num_str;
70:
71: while (*cp) {
72: if (!isDigit(cp)) {
73: invalid_num:
74: rprintf(FERROR, "Invalid ID number: %s\n", num_str);
75: exit_cleanup(RERR_SYNTAX);
76: }
77: tmp = num * 10 + *cp++ - '0';
78: if (tmp < num)
79: goto invalid_num;
80: num = tmp;
81: }
82:
83: return num;
84: }
85:
86: static struct idlist *add_to_list(struct idlist **root, id_t id, union name_or_id noiu,
87: id_t id2, uint16 flags)
88: {
89: struct idlist *node = new(struct idlist);
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: const char *uid_to_user(uid_t uid)
101: {
102: const char *name = NULL;
103:
104: if (namecvt_pid) {
105: id_t id = uid;
106: namecvt_call("uid", &name, &id);
107: } else {
108: struct passwd *pass = getpwuid(uid);
109: if (pass)
110: name = strdup(pass->pw_name);
111: }
112:
113: return name;
114: }
115:
116: /* turn a gid into a group name */
117: const char *gid_to_group(gid_t gid)
118: {
119: const char *name = NULL;
120:
121: if (namecvt_pid) {
122: id_t id = gid;
123: namecvt_call("gid", &name, &id);
124: } else {
125: struct group *grp = getgrgid(gid);
126: if (grp)
127: name = strdup(grp->gr_name);
128: }
129:
130: return name;
131: }
132:
133: /* Parse a user name or (optionally) a number into a uid */
134: int user_to_uid(const char *name, uid_t *uid_p, BOOL num_ok)
135: {
136: if (!name || !*name)
137: return 0;
138:
139: if (num_ok && name[strspn(name, "0123456789")] == '\0') {
140: *uid_p = id_parse(name);
141: return 1;
142: }
143:
144: if (namecvt_pid) {
145: id_t id;
146: if (!namecvt_call("usr", &name, &id))
147: return 0;
148: *uid_p = id;
149: } else {
150: struct passwd *pass = getpwnam(name);
151: if (!pass)
152: return 0;
153: *uid_p = pass->pw_uid;
154: }
155:
156: return 1;
157: }
158:
159: /* Parse a group name or (optionally) a number into a gid */
160: int group_to_gid(const char *name, gid_t *gid_p, BOOL num_ok)
161: {
162: if (!name || !*name)
163: return 0;
164:
165: if (num_ok && name[strspn(name, "0123456789")] == '\0') {
166: *gid_p = id_parse(name);
167: return 1;
168: }
169:
170: if (namecvt_pid) {
171: id_t id;
172: if (!namecvt_call("grp", &name, &id))
173: return 0;
174: *gid_p = id;
175: } else {
176: struct group *grp = getgrnam(name);
177: if (!grp)
178: return 0;
179: *gid_p = grp->gr_gid;
180: }
181:
182: return 1;
183: }
184:
185: static int is_in_group(gid_t gid)
186: {
187: #ifdef HAVE_GETGROUPS
188: static gid_t last_in;
189: static int ngroups = -2, last_out = -1;
190: static GETGROUPS_T *gidset;
191: int n;
192:
193: if (gid == last_in && last_out >= 0)
194: return last_out;
195: if (ngroups < -1) {
196: if ((ngroups = getgroups(0, NULL)) < 0)
197: ngroups = 0;
198: gidset = new_array(GETGROUPS_T, ngroups+1);
199: if (ngroups > 0)
200: ngroups = getgroups(ngroups, gidset);
201: /* The default gid might not be in the list on some systems. */
202: for (n = 0; n < ngroups; n++) {
203: if (gidset[n] == our_gid)
204: break;
205: }
206: if (n == ngroups)
207: gidset[ngroups++] = our_gid;
208: if (DEBUG_GTE(OWN, 2)) {
209: int pos;
210: char *gidbuf = new_array(char, ngroups*21+32);
211: pos = snprintf(gidbuf, 32, "process has %d gid%s: ", ngroups, ngroups == 1? "" : "s");
212: for (n = 0; n < ngroups; n++) {
213: pos += snprintf(gidbuf+pos, 21, " %d", (int)gidset[n]);
214: }
215: rprintf(FINFO, "%s\n", gidbuf);
216: free(gidbuf);
217: }
218: }
219:
220: last_in = gid;
221: for (n = 0; n < ngroups; n++) {
222: if (gidset[n] == gid)
223: return last_out = 1;
224: }
225: return last_out = 0;
226:
227: #else
228: return gid == our_gid;
229: #endif
230: }
231:
232: /* Add a uid/gid to its list of ids. Only called on receiving side. */
233: static struct idlist *recv_add_id(struct idlist **idlist_ptr, struct idlist *idmap,
234: id_t id, const char *name)
235: {
236: struct idlist *node;
237: union name_or_id noiu;
238: int flag;
239: id_t id2;
240:
241: noiu.name = name; /* ensure that add_to_list() gets the raw value. */
242: if (!name)
243: name = "";
244:
245: for (node = idmap; node; node = node->next) {
246: if (node->flags & NFLAGS_WILD_NAME_MATCH) {
247: if (!wildmatch(node->u.name, name))
248: continue;
249: } else if (node->flags & NFLAGS_NAME_MATCH) {
250: if (strcmp(node->u.name, name) != 0)
251: continue;
252: } else if (node->u.max_id) {
253: if (id < node->id || id > node->u.max_id)
254: continue;
255: } else {
256: if (node->id != id)
257: continue;
258: }
259: break;
260: }
261: if (node)
262: id2 = node->id2;
263: else if (*name && id) {
264: if (idlist_ptr == &uidlist) {
265: uid_t uid;
266: id2 = user_to_uid(name, &uid, False) ? uid : id;
267: } else {
268: gid_t gid;
269: id2 = group_to_gid(name, &gid, False) ? gid : id;
270: }
271: } else
272: id2 = id;
273:
274: flag = idlist_ptr == &gidlist && !am_root && !is_in_group(id2) ? FLAG_SKIP_GROUP : 0;
275: node = add_to_list(idlist_ptr, id, noiu, id2, flag);
276:
277: if (DEBUG_GTE(OWN, 2)) {
278: rprintf(FINFO, "%sid %u(%s) maps to %u\n",
279: idlist_ptr == &uidlist ? "u" : "g",
280: (unsigned)id, name, (unsigned)id2);
281: }
282:
283: return node;
284: }
285:
286: /* this function is a definite candidate for a faster algorithm */
287: uid_t match_uid(uid_t uid)
288: {
289: static struct idlist *last = NULL;
290: struct idlist *list;
291:
292: if (last && uid == last->id)
293: return last->id2;
294:
295: for (list = uidlist; list; list = list->next) {
296: if (list->id == uid)
297: break;
298: }
299:
300: if (!list)
301: list = recv_add_id(&uidlist, uidmap, uid, NULL);
302: last = list;
303:
304: return list->id2;
305: }
306:
307: gid_t match_gid(gid_t gid, uint16 *flags_ptr)
308: {
309: static struct idlist *last = NULL;
310: struct idlist *list;
311:
312: if (last && gid == last->id)
313: list = last;
314: else {
315: for (list = gidlist; list; list = list->next) {
316: if (list->id == gid)
317: break;
318: }
319: if (!list)
320: list = recv_add_id(&gidlist, gidmap, gid, NULL);
321: last = list;
322: }
323:
324: if (flags_ptr && list->flags & FLAG_SKIP_GROUP)
325: *flags_ptr |= FLAG_SKIP_GROUP;
326: return list->id2;
327: }
328:
329: /* Add a uid to the list of uids. Only called on sending side. */
330: const char *add_uid(uid_t uid)
331: {
332: struct idlist *list;
333: struct idlist *node;
334: union name_or_id noiu;
335:
336: for (list = uidlist; list; list = list->next) {
337: if (list->id == uid)
338: return NULL;
339: }
340:
341: noiu.name = uid_to_user(uid);
342: node = add_to_list(&uidlist, uid, noiu, 0, 0);
343: return node->u.name;
344: }
345:
346: /* Add a gid to the list of gids. Only called on sending side. */
347: const char *add_gid(gid_t gid)
348: {
349: struct idlist *list;
350: struct idlist *node;
351: union name_or_id noiu;
352:
353: for (list = gidlist; list; list = list->next) {
354: if (list->id == gid)
355: return NULL;
356: }
357:
358: noiu.name = gid_to_group(gid);
359: node = add_to_list(&gidlist, gid, noiu, 0, 0);
360: return node->u.name;
361: }
362:
363: static void send_one_name(int f, id_t id, const char *name)
364: {
365: int len;
366:
367: if (!name)
368: name = "";
369: if ((len = strlen(name)) > 255) /* Impossible? */
370: len = 255;
371:
372: write_varint30(f, id);
373: write_byte(f, len);
374: if (len)
375: write_buf(f, name, len);
376: }
377:
378: static void send_one_list(int f, struct idlist *idlist, int usernames)
379: {
380: struct idlist *list;
381:
382: /* we send sequences of id/byte-len/name */
383: for (list = idlist; list; list = list->next) {
384: if (list->id && list->u.name)
385: send_one_name(f, list->id, list->u.name);
386: }
387:
388: /* Terminate the uid list with 0 (which was excluded above).
389: * A modern rsync also sends the name of id 0. */
390: if (xmit_id0_names)
391: send_one_name(f, 0, usernames ? uid_to_user(0) : gid_to_group(0));
392: else
393: write_varint30(f, 0);
394: }
395:
396: /* send a complete uid/gid mapping to the peer */
397: void send_id_lists(int f)
398: {
399: if (preserve_uid || preserve_acls)
400: send_one_list(f, uidlist, 1);
401:
402: if (preserve_gid || preserve_acls)
403: send_one_list(f, gidlist, 0);
404: }
405:
406: uid_t recv_user_name(int f, uid_t uid)
407: {
408: struct idlist *node;
409: int len = read_byte(f);
410: char *name;
411:
412: if (len) {
413: name = new_array(char, len+1);
414: read_sbuf(f, name, len);
415: if (numeric_ids < 0) {
416: free(name);
417: name = NULL;
418: }
419: } else
420: name = NULL;
421:
422: node = recv_add_id(&uidlist, uidmap, uid, name); /* node keeps name's memory */
423: return node->id2;
424: }
425:
426: gid_t recv_group_name(int f, gid_t gid, uint16 *flags_ptr)
427: {
428: struct idlist *node;
429: int len = read_byte(f);
430: char *name;
431:
432: if (len) {
433: name = new_array(char, len+1);
434: read_sbuf(f, name, len);
435: if (numeric_ids < 0) {
436: free(name);
437: name = NULL;
438: }
439: } else
440: name = NULL;
441:
442: node = recv_add_id(&gidlist, gidmap, gid, name); /* node keeps name's memory */
443: if (flags_ptr && node->flags & FLAG_SKIP_GROUP)
444: *flags_ptr |= FLAG_SKIP_GROUP;
445: return node->id2;
446: }
447:
448: /* recv a complete uid/gid mapping from the peer and map the uid/gid
449: * in the file list to local names */
450: void recv_id_list(int f, struct file_list *flist)
451: {
452: id_t id;
453: int i;
454:
455: if ((preserve_uid || preserve_acls) && numeric_ids <= 0) {
456: /* read the uid list */
457: while ((id = read_varint30(f)) != 0)
458: recv_user_name(f, id);
459: if (xmit_id0_names)
460: recv_user_name(f, 0);
461: }
462:
463: if ((preserve_gid || preserve_acls) && numeric_ids <= 0) {
464: /* read the gid list */
465: while ((id = read_varint30(f)) != 0)
466: recv_group_name(f, id, NULL);
467: if (xmit_id0_names)
468: recv_group_name(f, 0, NULL);
469: }
470:
471: /* Now convert all the uids/gids from sender values to our values. */
472: #ifdef SUPPORT_ACLS
473: if (preserve_acls && (!numeric_ids || usermap || groupmap))
474: match_acl_ids();
475: #endif
476: if (am_root && preserve_uid && (!numeric_ids || usermap)) {
477: for (i = 0; i < flist->used; i++)
478: F_OWNER(flist->files[i]) = match_uid(F_OWNER(flist->files[i]));
479: }
480: if (preserve_gid && (!am_root || !numeric_ids || groupmap)) {
481: for (i = 0; i < flist->used; i++) {
482: F_GROUP(flist->files[i]) = match_gid(F_GROUP(flist->files[i]), &flist->files[i]->flags);
483: }
484: }
485: }
486:
487: void parse_name_map(char *map, BOOL usernames)
488: {
489: struct idlist **idmap_ptr = usernames ? &uidmap : &gidmap;
490: struct idlist **idlist_ptr = usernames ? &uidlist : &gidlist;
491: char *colon, *cp = map + strlen(map);
492: union name_or_id noiu;
493: id_t id1;
494: uint16 flags;
495:
496: /* Parse the list in reverse, so the order in the struct is right. */
497: while (1) {
498: while (cp > map && cp[-1] != ',') cp--;
499: if (!(colon = strchr(cp, ':'))) {
500: rprintf(FERROR, "No colon found in --%smap: %s\n",
501: usernames ? "user" : "group", cp);
502: exit_cleanup(RERR_SYNTAX);
503: }
504: if (!colon[1]) {
505: rprintf(FERROR, "No name found after colon --%smap: %s\n",
506: usernames ? "user" : "group", cp);
507: exit_cleanup(RERR_SYNTAX);
508: }
509: *colon = '\0';
510:
511: if (isDigit(cp)) {
512: char *dash = strchr(cp, '-');
513: if (strspn(cp, "0123456789-") != (size_t)(colon - cp)
514: || (dash && (!dash[1] || strchr(dash+1, '-')))) {
515: rprintf(FERROR, "Invalid number in --%smap: %s\n",
516: usernames ? "user" : "group", cp);
517: exit_cleanup(RERR_SYNTAX);
518: }
519: if (dash) {
520: *dash = '\0';
521: noiu.max_id = id_parse(dash+1);
522: } else
523: noiu.max_id = 0;
524: flags = 0;
525: id1 = id_parse(cp);
526: if (dash)
527: *dash = '-';
528: } else if (strpbrk(cp, "*[?")) {
529: flags = NFLAGS_WILD_NAME_MATCH;
530: noiu.name = cp;
531: id1 = 0;
532: } else {
533: flags = NFLAGS_NAME_MATCH;
534: noiu.name = cp;
535: id1 = 0;
536: }
537:
538: if (usernames) {
539: uid_t uid;
540: if (user_to_uid(colon+1, &uid, True))
541: add_to_list(idmap_ptr, id1, noiu, uid, flags);
542: else {
543: rprintf(FERROR, "Unknown --usermap name on receiver: %s\n", colon+1);
544: }
545: } else {
546: gid_t gid;
547: if (group_to_gid(colon+1, &gid, True))
548: add_to_list(idmap_ptr, id1, noiu, gid, flags);
549: else {
550: rprintf(FERROR, "Unknown --groupmap name on receiver: %s\n", colon+1);
551: }
552: }
553:
554: if (cp == map)
555: break;
556:
557: *--cp = '\0'; /* replace comma */
558: }
559:
560: /* If the sender isn't going to xmit the id0 name, we assume it's "root". */
561: if (!xmit_id0_names)
562: recv_add_id(idlist_ptr, *idmap_ptr, 0, numeric_ids ? NULL : "root");
563: }
564:
565: #ifdef HAVE_GETGROUPLIST
566: const char *getallgroups(uid_t uid, item_list *gid_list)
567: {
568: struct passwd *pw;
569: gid_t *gid_array;
570: int size;
571:
572: if ((pw = getpwuid(uid)) == NULL)
573: return "getpwuid failed";
574:
575: gid_list->count = 0; /* We're overwriting any items in the list */
576: (void)EXPAND_ITEM_LIST(gid_list, gid_t, 32);
577: size = gid_list->malloced;
578:
579: /* Get all the process's groups, with the pw_gid group first. */
580: if (getgrouplist(pw->pw_name, pw->pw_gid, gid_list->items, &size) < 0) {
581: if (size > (int)gid_list->malloced) {
582: gid_list->count = gid_list->malloced;
583: (void)EXPAND_ITEM_LIST(gid_list, gid_t, size);
584: if (getgrouplist(pw->pw_name, pw->pw_gid, gid_list->items, &size) < 0)
585: size = -1;
586: } else
587: size = -1;
588: if (size < 0)
589: return "getgrouplist failed";
590: }
591: gid_list->count = size;
592: gid_array = gid_list->items;
593:
594: /* Paranoia: is the default group not first in the list? */
595: if (gid_array[0] != pw->pw_gid) {
596: int j;
597: for (j = 1; j < size; j++) {
598: if (gid_array[j] == pw->pw_gid)
599: break;
600: }
601: if (j == size) { /* The default group wasn't found! */
602: (void)EXPAND_ITEM_LIST(gid_list, gid_t, size+1);
603: gid_array = gid_list->items;
604: }
605: gid_array[j] = gid_array[0];
606: gid_array[0] = pw->pw_gid;
607: }
608:
609: return NULL;
610: }
611: #endif
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