2 * Support rsync daemon authentication.
4 * Copyright (C) 1998-2000 Andrew Tridgell
5 * Copyright (C) 2002-2007 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.
23 extern char *password_file;
24 extern int log_got_error;
26 /***************************************************************************
27 encode a buffer using base64 - simple and slow algorithm. null terminates
29 ***************************************************************************/
30 void base64_encode(const char *buf, int len, char *out, int pad)
32 char *b64 = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
33 int bit_offset, byte_offset, idx, i;
34 const uchar *d = (const uchar *)buf;
35 int bytes = (len*8 + 5)/6;
37 for (i = 0; i < bytes; i++) {
38 byte_offset = (i*6)/8;
41 idx = (d[byte_offset] >> (2-bit_offset)) & 0x3F;
43 idx = (d[byte_offset] << (bit_offset-2)) & 0x3F;
44 if (byte_offset+1 < len) {
45 idx |= (d[byte_offset+1] >> (8-(bit_offset-2)));
51 while (pad && (i % 4))
57 /* Generate a challenge buffer and return it base64-encoded. */
58 static void gen_challenge(const char *addr, char *challenge)
61 char digest[MAX_DIGEST_LEN];
65 memset(input, 0, sizeof input);
67 strlcpy(input, addr, 17);
68 sys_gettimeofday(&tv);
69 SIVAL(input, 16, tv.tv_sec);
70 SIVAL(input, 20, tv.tv_usec);
71 SIVAL(input, 24, getpid());
74 sum_update(input, sizeof input);
75 len = sum_end(digest);
77 base64_encode(digest, len, challenge, 0);
81 /* Return the secret for a user from the secret file, null terminated.
82 * Maximum length is len (not counting the null). */
83 static int get_secret(int module, const char *user, char *secret, int len)
85 const char *fname = lp_secrets_file(module);
91 if (!fname || !*fname)
94 if ((fd = open(fname, O_RDONLY)) < 0)
97 if (do_stat(fname, &st) == -1) {
98 rsyserr(FLOG, errno, "stat(%s)", fname);
100 } else if (lp_strict_modes(module)) {
101 if ((st.st_mode & 06) != 0) {
102 rprintf(FLOG, "secrets file must not be other-accessible (see strict modes option)\n");
104 } else if (MY_UID() == 0 && st.st_uid != 0) {
105 rprintf(FLOG, "secrets file must be owned by root when running as root (see strict modes)\n");
110 rprintf(FLOG, "continuing without secrets file\n");
116 /* Reject attempt to match a comment. */
121 /* Try to find a line that starts with the user name and a ':'. */
124 if (read(fd, &ch, 1) != 1) {
133 else if (!*p && ch == ':')
140 /* Slurp the secret into the "secret" buffer. */
143 if (read(fd, s, 1) != 1 || *s == '\n')
156 static const char *getpassf(const char *filename)
159 char buffer[512], *p;
161 const char *envpw = getenv("RSYNC_PASSWORD");
166 if ((fd = open(filename,O_RDONLY)) < 0) {
167 rsyserr(FERROR, errno, "could not open password file \"%s\"",
170 rprintf(FINFO, "falling back to RSYNC_PASSWORD environment variable.\n");
174 if (do_stat(filename, &st) == -1) {
175 rsyserr(FERROR, errno, "stat(%s)", filename);
177 } else if ((st.st_mode & 06) != 0) {
178 rprintf(FERROR, "password file must not be other-accessible\n");
180 } else if (MY_UID() == 0 && st.st_uid != 0) {
181 rprintf(FERROR, "password file must be owned by root when running as root\n");
186 rprintf(FERROR, "continuing without password file\n");
188 rprintf(FINFO, "falling back to RSYNC_PASSWORD environment variable.\n");
192 n = read(fd, buffer, sizeof buffer - 1);
196 if ((p = strtok(buffer, "\n\r")) != NULL)
203 /* Generate an MD4 hash created from the combination of the password
204 * and the challenge string and return it base64-encoded. */
205 static void generate_hash(const char *in, const char *challenge, char *out)
207 char buf[MAX_DIGEST_LEN];
211 sum_update(in, strlen(in));
212 sum_update(challenge, strlen(challenge));
215 base64_encode(buf, len, out, 0);
218 /* Possibly negotiate authentication with the client. Use "leader" to
219 * start off the auth if necessary.
221 * Return NULL if authentication failed. Return "" if anonymous access.
222 * Otherwise return username.
224 char *auth_server(int f_in, int f_out, int module, const char *host,
225 const char *addr, const char *leader)
227 char *users = lp_auth_users(module);
228 char challenge[MAX_DIGEST_LEN*2];
229 char line[BIGPATHBUFLEN];
231 char pass2[MAX_DIGEST_LEN*2];
234 /* if no auth list then allow anyone in! */
235 if (!users || !*users)
238 gen_challenge(addr, challenge);
240 io_printf(f_out, "%s%s\n", leader, challenge);
242 if (!read_line_old(f_in, line, sizeof line)
243 || (pass = strchr(line, ' ')) == NULL) {
244 rprintf(FLOG, "auth failed on module %s from %s (%s): "
245 "invalid challenge response\n",
246 lp_name(module), host, addr);
251 if (!(users = strdup(users)))
252 out_of_memory("auth_server");
254 for (tok = strtok(users, " ,\t"); tok; tok = strtok(NULL, " ,\t")) {
255 if (wildmatch(tok, line))
261 rprintf(FLOG, "auth failed on module %s from %s (%s): "
262 "unauthorized user\n",
263 lp_name(module), host, addr);
267 memset(secret, 0, sizeof secret);
268 if (!get_secret(module, line, secret, sizeof secret - 1)) {
269 memset(secret, 0, sizeof secret);
270 rprintf(FLOG, "auth failed on module %s from %s (%s): "
271 "missing secret for user \"%s\"\n",
272 lp_name(module), host, addr, line);
276 generate_hash(secret, challenge, pass2);
277 memset(secret, 0, sizeof secret);
279 if (strcmp(pass, pass2) != 0) {
280 rprintf(FLOG, "auth failed on module %s from %s (%s): "
281 "password mismatch\n",
282 lp_name(module), host, addr);
289 void auth_client(int fd, const char *user, const char *challenge)
292 char pass2[MAX_DIGEST_LEN*2];
297 if (!(pass = getpassf(password_file))
298 && !(pass = getenv("RSYNC_PASSWORD"))) {
299 /* XXX: cyeoh says that getpass is deprecated, because
300 * it may return a truncated password on some systems,
301 * and it is not in the LSB.
303 * Andrew Klein says that getpassphrase() is present
304 * on Solaris and reads up to 256 characters.
306 * OpenBSD has a readpassphrase() that might be more suitable.
308 pass = getpass("Password: ");
311 /* Any errors output during password handling aren't transfer errors. */
317 generate_hash(pass, challenge, pass2);
318 io_printf(fd, "%s %s\n", user, pass2);