1 /*
2 * CDDL HEADER START
3 *
4 * The contents of this file are subject to the terms of the
5 * Common Development and Distribution License, Version 1.0 only
6 * (the "License"). You may not use this file except in compliance
7 * with the License.
8 *
9 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
10 * or http://www.opensolaris.org/os/licensing.
11 * See the License for the specific language governing permissions
12 * and limitations under the License.
13 *
14 * When distributing Covered Code, include this CDDL HEADER in each
15 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
16 * If applicable, add the following below this CDDL HEADER, with the
17 * fields enclosed by brackets "[]" replaced with your own identifying
18 * information: Portions Copyright [yyyy] [name of copyright owner]
19 *
20 * CDDL HEADER END
21 */
22 /*
23 * warmstart.c
24 * Allows for gathering of registrations from a earlier dumped file.
25 *
26 * Copyright 1990,2002-2003 Sun Microsystems, Inc. All rights reserved.
27 * Use is subject to license terms.
28 */
29 /*
30 * Copyright 2013 Nexenta Systems, Inc. All rights reserved.
31 */
32
33 #include <stdio.h>
34 #include <errno.h>
35 #include <rpc/rpc.h>
36 #include <rpc/rpcb_prot.h>
37 #include <sys/types.h>
38 #include <sys/stat.h>
39 #ifdef PORTMAP
40 #include <netinet/in.h>
41 #include <rpc/pmap_prot.h>
42 #endif
43 #include "rpcbind.h"
44 #include <syslog.h>
45 #include <unistd.h>
46 #include <rpcsvc/daemon_utils.h>
47 #include <assert.h>
48
49 /* These files keep the pmap_list and rpcb_list in XDR format */
50 static const char rpcbfile[] = DAEMON_DIR "/rpcbind.file";
51 #ifdef PORTMAP
52 static const char pmapfile[] = DAEMON_DIR "/portmap.file";
53 #endif
54
55 static FILE *
open_tmp_file(const char * filename)56 open_tmp_file(const char *filename)
57 {
58 int fd;
59 FILE *fp;
60
61 /*
62 * Remove any existing files, and create a new one.
63 * Ensure that rpcbind is not forced to overwrite
64 * a file pointed to by a symbolic link created
65 * by an attacker.
66 * Use open O_CREAT|O_EXCL so file is not created
67 * between unlink() and open() operation.
68 */
69 if (unlink(filename) == -1) {
70 if (errno != ENOENT)
71 return (NULL);
72 }
73 fd = open(filename, O_CREAT|O_EXCL|O_WRONLY, 0600);
74 if (fd == -1)
75 return (NULL);
76 fp = fdopen(fd, "w");
77 if (fp == NULL) {
78 close(fd);
79 return (NULL);
80 }
81
82 return (fp);
83 }
84
85 static bool_t
write_struct(const char * filename,xdrproc_t structproc,void * list)86 write_struct(const char *filename, xdrproc_t structproc, void *list)
87 {
88 FILE *fp;
89 XDR xdrs;
90
91 fp = open_tmp_file(filename);
92 if (fp == NULL) {
93 int i;
94
95 for (i = 0; i < 10; i++)
96 close(i);
97 fp = open_tmp_file(filename);
98 if (fp == NULL) {
99 syslog(LOG_ERR,
100 "cannot open file = %s for writing", filename);
101 syslog(LOG_ERR, "cannot save any registration");
102 return (FALSE);
103 }
104 }
105 xdrstdio_create(&xdrs, fp, XDR_ENCODE);
106
107 if (structproc(&xdrs, list) == FALSE) {
108 XDR_DESTROY(&xdrs);
109 syslog(LOG_ERR, "rpcbind: xdr_%s: failed", filename);
110 fclose(fp);
111 return (FALSE);
112 }
113 XDR_DESTROY(&xdrs);
114 fclose(fp);
115 return (TRUE);
116 }
117
118 static bool_t
read_struct(const char * filename,xdrproc_t structproc,void * list)119 read_struct(const char *filename, xdrproc_t structproc, void *list)
120 {
121 int fd;
122 FILE *fp = NULL;
123 XDR xdrs;
124 struct stat sbuf_fstat, sbuf_lstat;
125
126 fd = open(filename, O_RDONLY, 0600);
127 if (fd == -1) {
128 fprintf(stderr,
129 "rpcbind: cannot open file = %s for reading\n", filename);
130 goto error;
131 }
132 fp = fdopen(fd, "r");
133 if (fp == NULL) {
134 close(fd);
135 fprintf(stderr,
136 "rpcbind: cannot open file = %s for reading\n", filename);
137 goto error;
138 }
139 if (fstat(fd, &sbuf_fstat) != 0) {
140 fprintf(stderr,
141 "rpcbind: cannot stat file = %s for reading\n", filename);
142 goto error;
143 }
144 if (sbuf_fstat.st_uid != DAEMON_UID ||
145 (!S_ISREG(sbuf_fstat.st_mode)) ||
146 (sbuf_fstat.st_mode & S_IRWXG) ||
147 (sbuf_fstat.st_mode & S_IRWXO) ||
148 (sbuf_fstat.st_nlink != 1)) {
149 fprintf(stderr, "rpcbind: invalid permissions on file = %s for "
150 "reading\n", filename);
151 goto error;
152 }
153 /*
154 * Make sure that the pathname for fstat and lstat is the same and
155 * that it's not a link. An attacker can create symbolic or
156 * hard links and use them to gain unauthorised access to the
157 * system when rpcbind aborts or terminates on SIGINT or SIGTERM.
158 */
159 if (lstat(filename, &sbuf_lstat) != 0) {
160 fprintf(stderr,
161 "rpcbind: cannot lstat file = %s for reading\n", filename);
162 goto error;
163 }
164 if (sbuf_lstat.st_uid != DAEMON_UID ||
165 (!S_ISREG(sbuf_lstat.st_mode)) ||
166 (sbuf_lstat.st_mode & S_IRWXG) ||
167 (sbuf_lstat.st_mode & S_IRWXO) ||
168 (sbuf_lstat.st_nlink != 1) ||
169 (sbuf_fstat.st_dev != sbuf_lstat.st_dev) ||
170 (sbuf_fstat.st_ino != sbuf_lstat.st_ino)) {
171 fprintf(stderr, "rpcbind: invalid lstat permissions on file = "
172 "%s for reading\n", filename);
173 goto error;
174 }
175 xdrstdio_create(&xdrs, fp, XDR_DECODE);
176
177 if (structproc(&xdrs, list) == FALSE) {
178 XDR_DESTROY(&xdrs);
179 fprintf(stderr, "rpcbind: xdr_%s: failed\n", filename);
180 goto error;
181 }
182 XDR_DESTROY(&xdrs);
183 fclose(fp);
184 return (TRUE);
185
186 error:
187 fprintf(stderr, "rpcbind: will start from scratch\n");
188 if (fp != NULL)
189 fclose(fp);
190 return (FALSE);
191 }
192
193 void
write_warmstart(void)194 write_warmstart(void)
195 {
196 assert(RW_WRITE_HELD(&list_rbl_lock));
197 (void) write_struct(rpcbfile, xdr_rpcblist_ptr, &list_rbl);
198 #ifdef PORTMAP
199 assert(RW_WRITE_HELD(&list_pml_lock));
200 (void) write_struct(pmapfile, xdr_pmaplist_ptr, &list_pml);
201 #endif
202
203 }
204
205 void
read_warmstart(void)206 read_warmstart(void)
207 {
208 rpcblist_ptr tmp_rpcbl = NULL;
209 #ifdef PORTMAP
210 pmaplist_ptr tmp_pmapl = NULL;
211 #endif
212
213 if (read_struct(rpcbfile, xdr_rpcblist_ptr, &tmp_rpcbl) == FALSE)
214 return;
215
216 #ifdef PORTMAP
217 if (read_struct(pmapfile, xdr_pmaplist_ptr, &tmp_pmapl) == FALSE) {
218 xdr_free((xdrproc_t)xdr_rpcblist_ptr, (char *)&tmp_rpcbl);
219 return;
220 }
221 #endif
222
223 xdr_free((xdrproc_t)xdr_rpcblist_ptr, (char *)&list_rbl);
224 list_rbl = tmp_rpcbl;
225 #ifdef PORTMAP
226 xdr_free((xdrproc_t)xdr_pmaplist_ptr, (char *)&list_pml);
227 list_pml = (pmaplist *)tmp_pmapl;
228 #endif
229 }
230