1/*
2 * Copyright (c) 2022 Damien Miller <djm@mindrot.org>
3 *
4 * Permission to use, copy, modify, and distribute this software for any
5 * purpose with or without fee is hereby granted, provided that the above
6 * copyright notice and this permission notice appear in all copies.
7 *
8 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
9 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
10 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
11 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
12 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
13 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
14 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
15 */
16
17/* sftp client user/group lookup and caching */
18
19#include "includes.h"
20
21#include <sys/types.h>
22#include <openbsd-compat/sys-tree.h>
23
24#include <stdlib.h>
25#include <stdarg.h>
26#include <string.h>
27
28#include "log.h"
29#include "xmalloc.h"
30
31#include "sftp-common.h"
32#include "sftp-client.h"
33#include "sftp-usergroup.h"
34
35/* Tree of id, name */
36struct idname {
37        u_int id;
38	char *name;
39        RB_ENTRY(idname) entry;
40	/* XXX implement bounded cache as TAILQ */
41};
42static int
43idname_cmp(struct idname *a, struct idname *b)
44{
45	if (a->id == b->id)
46		return 0;
47	return a->id > b->id ? 1 : -1;
48}
49RB_HEAD(idname_tree, idname);
50RB_GENERATE_STATIC(idname_tree, idname, entry, idname_cmp)
51
52static struct idname_tree user_idname = RB_INITIALIZER(&user_idname);
53static struct idname_tree group_idname = RB_INITIALIZER(&group_idname);
54
55static void
56idname_free(struct idname *idname)
57{
58	if (idname == NULL)
59		return;
60	free(idname->name);
61	free(idname);
62}
63
64static void
65idname_enter(struct idname_tree *tree, u_int id, const char *name)
66{
67	struct idname *idname;
68
69	if ((idname = xcalloc(1, sizeof(*idname))) == NULL)
70		fatal_f("alloc");
71	idname->id = id;
72	idname->name = xstrdup(name);
73	if (RB_INSERT(idname_tree, tree, idname) != NULL)
74		idname_free(idname);
75}
76
77static const char *
78idname_lookup(struct idname_tree *tree, u_int id)
79{
80	struct idname idname, *found;
81
82	memset(&idname, 0, sizeof(idname));
83	idname.id = id;
84	if ((found = RB_FIND(idname_tree, tree, &idname)) != NULL)
85		return found->name;
86	return NULL;
87}
88
89static void
90freenames(char **names, u_int nnames)
91{
92	u_int i;
93
94	if (names == NULL)
95		return;
96	for (i = 0; i < nnames; i++)
97		free(names[i]);
98	free(names);
99}
100
101static void
102lookup_and_record(struct sftp_conn *conn,
103    u_int *uids, u_int nuids, u_int *gids, u_int ngids)
104{
105	int r;
106	u_int i;
107	char **usernames = NULL, **groupnames = NULL;
108
109	if ((r = sftp_get_users_groups_by_id(conn, uids, nuids, gids, ngids,
110	    &usernames, &groupnames)) != 0) {
111		debug_fr(r, "sftp_get_users_groups_by_id");
112		return;
113	}
114	for (i = 0; i < nuids; i++) {
115		if (usernames[i] == NULL) {
116			debug3_f("uid %u not resolved", uids[i]);
117			continue;
118		}
119		debug3_f("record uid %u => \"%s\"", uids[i], usernames[i]);
120		idname_enter(&user_idname, uids[i], usernames[i]);
121	}
122	for (i = 0; i < ngids; i++) {
123		if (groupnames[i] == NULL) {
124			debug3_f("gid %u not resolved", gids[i]);
125			continue;
126		}
127		debug3_f("record gid %u => \"%s\"", gids[i], groupnames[i]);
128		idname_enter(&group_idname, gids[i], groupnames[i]);
129	}
130	freenames(usernames, nuids);
131	freenames(groupnames, ngids);
132}
133
134static int
135has_id(u_int id, u_int *ids, u_int nids)
136{
137	u_int i;
138
139	if (nids == 0)
140		return 0;
141
142	/* XXX O(N^2) */
143	for (i = 0; i < nids; i++) {
144		if (ids[i] == id)
145			break;
146	}
147	return i < nids;
148}
149
150static void
151collect_ids_from_glob(glob_t *g, int user, u_int **idsp, u_int *nidsp)
152{
153	u_int id, i, n = 0, *ids = NULL;
154
155	for (i = 0; g->gl_pathv[i] != NULL; i++) {
156		if (user) {
157			if (ruser_name(g->gl_statv[i]->st_uid) != NULL)
158				continue; /* Already seen */
159			id = (u_int)g->gl_statv[i]->st_uid;
160		} else {
161			if (rgroup_name(g->gl_statv[i]->st_gid) != NULL)
162				continue; /* Already seen */
163			id = (u_int)g->gl_statv[i]->st_gid;
164		}
165		if (has_id(id, ids, n))
166			continue;
167		ids = xrecallocarray(ids, n, n + 1, sizeof(*ids));
168		ids[n++] = id;
169	}
170	*idsp = ids;
171	*nidsp = n;
172}
173
174void
175get_remote_user_groups_from_glob(struct sftp_conn *conn, glob_t *g)
176{
177	u_int *uids = NULL, nuids = 0, *gids = NULL, ngids = 0;
178
179	if (!sftp_can_get_users_groups_by_id(conn))
180		return;
181
182	collect_ids_from_glob(g, 1, &uids, &nuids);
183	collect_ids_from_glob(g, 0, &gids, &ngids);
184	lookup_and_record(conn, uids, nuids, gids, ngids);
185	free(uids);
186	free(gids);
187}
188
189static void
190collect_ids_from_dirents(SFTP_DIRENT **d, int user, u_int **idsp, u_int *nidsp)
191{
192	u_int id, i, n = 0, *ids = NULL;
193
194	for (i = 0; d[i] != NULL; i++) {
195		if (user) {
196			if (ruser_name((uid_t)(d[i]->a.uid)) != NULL)
197				continue; /* Already seen */
198			id = d[i]->a.uid;
199		} else {
200			if (rgroup_name((gid_t)(d[i]->a.gid)) != NULL)
201				continue; /* Already seen */
202			id = d[i]->a.gid;
203		}
204		if (has_id(id, ids, n))
205			continue;
206		ids = xrecallocarray(ids, n, n + 1, sizeof(*ids));
207		ids[n++] = id;
208	}
209	*idsp = ids;
210	*nidsp = n;
211}
212
213void
214get_remote_user_groups_from_dirents(struct sftp_conn *conn, SFTP_DIRENT **d)
215{
216	u_int *uids = NULL, nuids = 0, *gids = NULL, ngids = 0;
217
218	if (!sftp_can_get_users_groups_by_id(conn))
219		return;
220
221	collect_ids_from_dirents(d, 1, &uids, &nuids);
222	collect_ids_from_dirents(d, 0, &gids, &ngids);
223	lookup_and_record(conn, uids, nuids, gids, ngids);
224	free(uids);
225	free(gids);
226}
227
228const char *
229ruser_name(uid_t uid)
230{
231	return idname_lookup(&user_idname, (u_int)uid);
232}
233
234const char *
235rgroup_name(uid_t gid)
236{
237	return idname_lookup(&group_idname, (u_int)gid);
238}
239
240