summaryrefslogtreecommitdiff
path: root/uidlist.c
blob: 3d9c774ea9d31303dc98e748db12dbdf62193cd0 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
/*
 * Handle the mapping of uid/gid and user/group names between systems.
 *
 * Copyright (C) 1996 Andrew Tridgell
 * Copyright (C) 1996 Paul Mackerras
 * Copyright (C) 2004-2008 Wayne Davison
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 3 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License along
 * with this program; if not, visit the http://fsf.org website.
 */

/* If the source username/group does not exist on the target then use
 * the numeric IDs.  Never do any mapping for uid=0 or gid=0 as these
 * are special. */

#include "rsync.h"
#include "io.h"

extern int verbose;
extern int am_root;
extern int preserve_uid;
extern int preserve_gid;
extern int preserve_acls;
extern int numeric_ids;

#ifdef HAVE_GETGROUPS
# ifndef GETGROUPS_T
#  define GETGROUPS_T gid_t
# endif
#endif

#define GID_NONE ((gid_t)-1)

struct idlist {
	struct idlist *next;
	const char *name;
	id_t id, id2;
	uint16 flags;
};

static struct idlist *uidlist;
static struct idlist *gidlist;

static struct idlist *add_to_list(struct idlist **root, id_t id, const char *name,
				  id_t id2, uint16 flags)
{
	struct idlist *node = new(struct idlist);
	if (!node)
		out_of_memory("add_to_list");
	node->next = *root;
	node->name = name;
	node->id = id;
	node->id2 = id2;
	node->flags = flags;
	*root = node;
	return node;
}

/* turn a uid into a user name */
static const char *uid_to_name(uid_t uid)
{
	struct passwd *pass = getpwuid(uid);
	if (pass)
		return strdup(pass->pw_name);
	return NULL;
}

/* turn a gid into a group name */
static const char *gid_to_name(gid_t gid)
{
	struct group *grp = getgrgid(gid);
	if (grp)
		return strdup(grp->gr_name);
	return NULL;
}

static uid_t map_uid(uid_t id, const char *name)
{
	uid_t uid;
	if (id != 0 && name_to_uid(name, &uid))
		return uid;
	return id;
}

static gid_t map_gid(gid_t id, const char *name)
{
	gid_t gid;
	if (id != 0 && name_to_gid(name, &gid))
		return gid;
	return id;
}

static int is_in_group(gid_t gid)
{
#ifdef HAVE_GETGROUPS
	static gid_t last_in = GID_NONE, last_out;
	static int ngroups = -2;
	static GETGROUPS_T *gidset;
	int n;

	if (gid == last_in)
		return last_out;
	if (ngroups < -1) {
		gid_t mygid = MY_GID();
		if ((ngroups = getgroups(0, NULL)) < 0)
			ngroups = 0;
		gidset = new_array(GETGROUPS_T, ngroups+1);
		if (!gidset)
			out_of_memory("is_in_group");
		if (ngroups > 0)
			ngroups = getgroups(ngroups, gidset);
		/* The default gid might not be in the list on some systems. */
		for (n = 0; n < ngroups; n++) {
			if (gidset[n] == mygid)
				break;
		}
		if (n == ngroups)
			gidset[ngroups++] = mygid;
		if (verbose > 3) {
			int pos;
			char *gidbuf = new_array(char, ngroups*21+32);
			if (!gidbuf)
				out_of_memory("is_in_group");
			pos = snprintf(gidbuf, 32, "process has %d gid%s: ",
				       ngroups, ngroups == 1? "" : "s");
			for (n = 0; n < ngroups; n++) {
				pos += snprintf(gidbuf+pos, 21, " %d", (int)gidset[n]);
			}
			rprintf(FINFO, "%s\n", gidbuf);
			free(gidbuf);
		}
	}

	last_in = gid;
	for (n = 0; n < ngroups; n++) {
		if (gidset[n] == gid)
			return last_out = 1;
	}
	return last_out = 0;

#else
	static gid_t mygid = GID_NONE;
	if (mygid == GID_NONE) {
		mygid = MY_GID();
		if (verbose > 3)
			rprintf(FINFO, "process has gid %u\n", (unsigned)mygid);
	}
	return gid == mygid;
#endif
}

/* Add a uid to the list of uids.  Only called on receiving side. */
static struct idlist *recv_add_uid(uid_t id, const char *name)
{
	uid_t id2 = name ? map_uid(id, name) : id;
	struct idlist *node;

	node = add_to_list(&uidlist, id, name, id2, 0);

	if (verbose > 3) {
		rprintf(FINFO, "uid %u(%s) maps to %u\n",
			(unsigned)id, name ? name : "", (unsigned)id2);
	}

	return node;
}

/* Add a gid to the list of gids.  Only called on receiving side. */
static struct idlist *recv_add_gid(gid_t id, const char *name)
{
	gid_t id2 = name ? map_gid(id, name) : id;
	struct idlist *node;

	node = add_to_list(&gidlist, id, name, id2,
		!am_root && !is_in_group(id2) ? FLAG_SKIP_GROUP : 0);

	if (verbose > 3) {
		rprintf(FINFO, "gid %u(%s) maps to %u\n",
			(unsigned)id, name ? name : "", (unsigned)id2);
	}

	return node;
}

/* this function is a definate candidate for a faster algorithm */
uid_t match_uid(uid_t uid)
{
	static uid_t last_in, last_out;
	struct idlist *list;

	if (uid == 0)
		return 0;

	if (uid == last_in)
		return last_out;

	last_in = uid;

	for (list = uidlist; list; list = list->next) {
		if (list->id == uid)
			return last_out = list->id2;
	}

	return last_out = uid;
}

gid_t match_gid(gid_t gid, uint16 *flags_ptr)
{
	static struct idlist *last = NULL;
	struct idlist *list;

	if (last && gid == last->id)
		list = last;
	else {
		for (list = gidlist; list; list = list->next) {
			if (list->id == gid)
				break;
		}
		if (!list)
			list = recv_add_gid(gid, NULL);
		last = list;
	}

	if (flags_ptr && list->flags & FLAG_SKIP_GROUP)
		*flags_ptr |= FLAG_SKIP_GROUP;
	return list->id2;
}

/* Add a uid to the list of uids.  Only called on sending side. */
const char *add_uid(uid_t uid)
{
	struct idlist *list;
	struct idlist *node;

	if (uid == 0)	/* don't map root */
		return NULL;

	for (list = uidlist; list; list = list->next) {
		if (list->id == uid)
			return NULL;
	}

	node = add_to_list(&uidlist, uid, uid_to_name(uid), 0, 0);
	return node->name;
}

/* Add a gid to the list of gids.  Only called on sending side. */
const char *add_gid(gid_t gid)
{
	struct idlist *list;
	struct idlist *node;

	if (gid == 0)	/* don't map root */
		return NULL;

	for (list = gidlist; list; list = list->next) {
		if (list->id == gid)
			return NULL;
	}

	node = add_to_list(&gidlist, gid, gid_to_name(gid), 0, 0);
	return node->name;
}

/* send a complete uid/gid mapping to the peer */
void send_id_list(int f)
{
	struct idlist *list;

	if (preserve_uid || preserve_acls) {
		int len;
		/* we send sequences of uid/byte-length/name */
		for (list = uidlist; list; list = list->next) {
			if (!list->name)
				continue;
			len = strlen(list->name);
			write_varint30(f, list->id);
			write_byte(f, len);
			write_buf(f, list->name, len);
		}

		/* terminate the uid list with a 0 uid. We explicitly exclude
		 * 0 from the list */
		write_varint30(f, 0);
	}

	if (preserve_gid || preserve_acls) {
		int len;
		for (list = gidlist; list; list = list->next) {
			if (!list->name)
				continue;
			len = strlen(list->name);
			write_varint30(f, list->id);
			write_byte(f, len);
			write_buf(f, list->name, len);
		}
		write_varint30(f, 0);
	}
}

uid_t recv_user_name(int f, uid_t uid)
{
	struct idlist *node;
	int len = read_byte(f);
	char *name = new_array(char, len+1);
	if (!name)
		out_of_memory("recv_user_name");
	read_sbuf(f, name, len);
	if (numeric_ids < 0) {
		free(name);
		name = NULL;
	}
	node = recv_add_uid(uid, name); /* node keeps name's memory */
	return node->id2;
}

gid_t recv_group_name(int f, gid_t gid, uint16 *flags_ptr)
{
	struct idlist *node;
	int len = read_byte(f);
	char *name = new_array(char, len+1);
	if (!name)
		out_of_memory("recv_group_name");
	read_sbuf(f, name, len);
	if (numeric_ids < 0) {
		free(name);
		name = NULL;
	}
	node = recv_add_gid(gid, name); /* node keeps name's memory */
	if (flags_ptr && node->flags & FLAG_SKIP_GROUP)
		*flags_ptr |= FLAG_SKIP_GROUP;
	return node->id2;
}

/* recv a complete uid/gid mapping from the peer and map the uid/gid
 * in the file list to local names */
void recv_id_list(int f, struct file_list *flist)
{
	id_t id;
	int i;

	if ((preserve_uid || preserve_acls) && numeric_ids <= 0) {
		/* read the uid list */
		while ((id = read_varint30(f)) != 0)
			recv_user_name(f, id);
	}

	if ((preserve_gid || preserve_acls) && numeric_ids <= 0) {
		/* read the gid list */
		while ((id = read_varint30(f)) != 0)
			recv_group_name(f, id, NULL);
	}

	/* Now convert all the uids/gids from sender values to our values. */
#ifdef SUPPORT_ACLS
	if (preserve_acls && !numeric_ids)
		match_acl_ids();
#endif
	if (am_root && preserve_uid && !numeric_ids) {
		for (i = 0; i < flist->used; i++)
			F_OWNER(flist->files[i]) = match_uid(F_OWNER(flist->files[i]));
	}
	if (preserve_gid && (!am_root || !numeric_ids)) {
		for (i = 0; i < flist->used; i++) {
			F_GROUP(flist->files[i]) = match_gid(F_GROUP(flist->files[i]),
							     &flist->files[i]->flags);
		}
	}
}