2 * Support rsync daemon authentication.
4 * Copyright (C) 1998-2000 Andrew Tridgell
5 * Copyright (C) 2002-2020 Wayne Davison
7 * This program is free software; you can redistribute it and/or modify
8 * it under the terms of the GNU General Public License as published by
9 * the Free Software Foundation; either version 3 of the License, or
10 * (at your option) any later version.
12 * This program is distributed in the hope that it will be useful,
13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 * GNU General Public License for more details.
17 * You should have received a copy of the GNU General Public License along
18 * with this program; if not, visit the http://fsf.org website.
25 extern char *password_file;
27 /***************************************************************************
28 encode a buffer using base64 - simple and slow algorithm. null terminates
30 ***************************************************************************/
31 void base64_encode(const char *buf, int len, char *out, int pad)
33 char *b64 = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
34 int bit_offset, byte_offset, idx, i;
35 const uchar *d = (const uchar *)buf;
36 int bytes = (len*8 + 5)/6;
38 for (i = 0; i < bytes; i++) {
39 byte_offset = (i*6)/8;
42 idx = (d[byte_offset] >> (2-bit_offset)) & 0x3F;
44 idx = (d[byte_offset] << (bit_offset-2)) & 0x3F;
45 if (byte_offset+1 < len) {
46 idx |= (d[byte_offset+1] >> (8-(bit_offset-2)));
52 while (pad && (i % 4))
58 /* Generate a challenge buffer and return it base64-encoded. */
59 static void gen_challenge(const char *addr, char *challenge)
62 char digest[MAX_DIGEST_LEN];
66 memset(input, 0, sizeof input);
68 strlcpy(input, addr, 17);
69 sys_gettimeofday(&tv);
70 SIVAL(input, 16, tv.tv_sec);
71 SIVAL(input, 20, tv.tv_usec);
72 SIVAL(input, 24, getpid());
75 sum_update(input, sizeof input);
76 len = sum_end(digest);
78 base64_encode(digest, len, challenge, 0);
81 /* Generate an MD4 hash created from the combination of the password
82 * and the challenge string and return it base64-encoded. */
83 static void generate_hash(const char *in, const char *challenge, char *out)
85 char buf[MAX_DIGEST_LEN];
89 sum_update(in, strlen(in));
90 sum_update(challenge, strlen(challenge));
93 base64_encode(buf, len, out, 0);
96 /* Return the secret for a user from the secret file, null terminated.
97 * Maximum length is len (not counting the null). */
98 static const char *check_secret(int module, const char *user, const char *group,
99 const char *challenge, const char *pass)
102 char pass2[MAX_DIGEST_LEN*2];
103 const char *fname = lp_secrets_file(module);
106 int user_len = strlen(user);
107 int group_len = group ? strlen(group) : 0;
111 if (!fname || !*fname || (fh = fopen(fname, "r")) == NULL)
112 return "no secrets file";
114 if (do_fstat(fileno(fh), &st) == -1) {
115 rsyserr(FLOG, errno, "fstat(%s)", fname);
117 } else if (lp_strict_modes(module)) {
118 if ((st.st_mode & 06) != 0) {
119 rprintf(FLOG, "secrets file must not be other-accessible (see strict modes option)\n");
121 } else if (MY_UID() == 0 && st.st_uid != 0) {
122 rprintf(FLOG, "secrets file must be owned by root when running as root (see strict modes)\n");
128 return "ignoring secrets file";
132 /* Reject attempt to match a comment. */
134 return "invalid username";
137 /* Try to find a line that starts with the user (or @group) name and a ':'. */
138 err = "secret not found";
139 while ((user || group) && fgets(line, sizeof line, fh) != NULL) {
140 const char **ptr, *s = strtok(line, "\n\r");
152 if (!*ptr || strncmp(s, *ptr, len) != 0 || s[len] != ':')
154 generate_hash(s+len+1, challenge, pass2);
155 if (strcmp(pass, pass2) == 0) {
159 err = "password mismatch";
160 *ptr = NULL; /* Don't look for name again. */
165 force_memzero(line, sizeof line);
166 force_memzero(pass2, sizeof pass2);
171 static const char *getpassf(const char *filename)
174 char buffer[512], *p;
180 if (strcmp(filename, "-") == 0) {
181 n = fgets(buffer, sizeof buffer, stdin) == NULL ? -1 : (int)strlen(buffer);
185 if ((fd = open(filename,O_RDONLY)) < 0) {
186 rsyserr(FERROR, errno, "could not open password file %s", filename);
187 exit_cleanup(RERR_SYNTAX);
190 if (do_stat(filename, &st) == -1) {
191 rsyserr(FERROR, errno, "stat(%s)", filename);
192 exit_cleanup(RERR_SYNTAX);
194 if ((st.st_mode & 06) != 0) {
195 rprintf(FERROR, "ERROR: password file must not be other-accessible\n");
196 exit_cleanup(RERR_SYNTAX);
198 if (MY_UID() == 0 && st.st_uid != 0) {
199 rprintf(FERROR, "ERROR: password file must be owned by root when running as root\n");
200 exit_cleanup(RERR_SYNTAX);
203 n = read(fd, buffer, sizeof buffer - 1);
209 if ((p = strtok(buffer, "\n\r")) != NULL)
213 rprintf(FERROR, "ERROR: failed to read a password from %s\n", filename);
214 exit_cleanup(RERR_SYNTAX);
217 /* Possibly negotiate authentication with the client. Use "leader" to
218 * start off the auth if necessary.
220 * Return NULL if authentication failed. Return "" if anonymous access.
221 * Otherwise return username.
223 char *auth_server(int f_in, int f_out, int module, const char *host,
224 const char *addr, const char *leader)
226 char *users = lp_auth_users(module);
227 char challenge[MAX_DIGEST_LEN*2];
228 char line[BIGPATHBUFLEN];
229 char **auth_uid_groups = NULL;
230 int auth_uid_groups_cnt = -1;
231 const char *err = NULL;
232 int group_match = -1;
236 /* if no auth list then allow anyone in! */
237 if (!users || !*users)
240 gen_challenge(addr, challenge);
242 io_printf(f_out, "%s%s\n", leader, challenge);
244 if (!read_line_old(f_in, line, sizeof line, 0)
245 || (pass = strchr(line, ' ')) == NULL) {
246 rprintf(FLOG, "auth failed on module %s from %s (%s): "
247 "invalid challenge response\n",
248 lp_name(module), host, addr);
253 if (!(users = strdup(users)))
254 out_of_memory("auth_server");
256 for (tok = strtok(users, " ,\t"); tok; tok = strtok(NULL, " ,\t")) {
258 /* See if the user appended :deny, :ro, or :rw. */
259 if ((opts = strchr(tok, ':')) != NULL) {
261 opt_ch = isUpper(opts) ? toLower(opts) : *opts;
262 if (opt_ch == 'r') { /* handle ro and rw */
263 opt_ch = isUpper(opts+1) ? toLower(opts+1) : opts[1];
266 else if (opt_ch != 'w')
268 } else if (opt_ch != 'd') /* if it's not deny, ignore it */
273 /* Match the username */
274 if (wildmatch(tok, line))
277 #ifdef HAVE_GETGROUPLIST
279 /* See if authorizing user is a real user, and if so, see
280 * if it is in a group that matches tok+1 wildmat. */
281 if (auth_uid_groups_cnt < 0) {
282 item_list gid_list = EMPTY_ITEM_LIST;
284 if (!user_to_uid(line, &auth_uid, False)
285 || getallgroups(auth_uid, &gid_list) != NULL)
286 auth_uid_groups_cnt = 0;
288 gid_t *gid_array = gid_list.items;
289 auth_uid_groups_cnt = gid_list.count;
290 if ((auth_uid_groups = new_array(char *, auth_uid_groups_cnt)) == NULL)
291 out_of_memory("auth_server");
292 for (j = 0; j < auth_uid_groups_cnt; j++)
293 auth_uid_groups[j] = gid_to_group(gid_array[j]);
296 for (j = 0; j < auth_uid_groups_cnt; j++) {
297 if (auth_uid_groups[j] && wildmatch(tok+1, auth_uid_groups[j])) {
302 if (group_match >= 0)
305 rprintf(FLOG, "your computer doesn't support getgrouplist(), so no @group authorization is possible.\n");
313 err = "no matching rule";
314 else if (opt_ch == 'd')
315 err = "denied by rule";
317 char *group = group_match >= 0 ? auth_uid_groups[group_match] : NULL;
318 err = check_secret(module, line, group, challenge, pass);
321 force_memzero(challenge, sizeof challenge);
322 force_memzero(pass, strlen(pass));
324 if (auth_uid_groups) {
326 for (j = 0; j < auth_uid_groups_cnt; j++) {
327 if (auth_uid_groups[j])
328 free(auth_uid_groups[j]);
330 free(auth_uid_groups);
334 rprintf(FLOG, "auth failed on module %s from %s (%s) for %s: %s\n",
335 lp_name(module), host, addr, line, err);
341 else if (opt_ch == 'w')
347 void auth_client(int fd, const char *user, const char *challenge)
350 char pass2[MAX_DIGEST_LEN*2];
355 if (!(pass = getpassf(password_file))
356 && !(pass = getenv("RSYNC_PASSWORD"))) {
357 /* XXX: cyeoh says that getpass is deprecated, because
358 * it may return a truncated password on some systems,
359 * and it is not in the LSB.
361 * Andrew Klein says that getpassphrase() is present
362 * on Solaris and reads up to 256 characters.
364 * OpenBSD has a readpassphrase() that might be more suitable.
366 pass = getpass("Password: ");
372 generate_hash(pass, challenge, pass2);
373 io_printf(fd, "%s %s\n", user, pass2);