-/*
- Copyright (C) Andrew Tridgell 1998
-
- 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 2 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, write to the Free Software
- Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
-*/
-
-/* support rsync authentication */
+/*
+ * Support rsync daemon authentication.
+ *
+ * Copyright (C) 1998-2000 Andrew Tridgell
+ * Copyright (C) 2002-2008 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.
+ */
+
#include "rsync.h"
+extern char *password_file;
+
+/***************************************************************************
+encode a buffer using base64 - simple and slow algorithm. null terminates
+the result.
+ ***************************************************************************/
+void base64_encode(const char *buf, int len, char *out, int pad)
+{
+ char *b64 = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
+ int bit_offset, byte_offset, idx, i;
+ const uchar *d = (const uchar *)buf;
+ int bytes = (len*8 + 5)/6;
+
+ for (i = 0; i < bytes; i++) {
+ byte_offset = (i*6)/8;
+ bit_offset = (i*6)%8;
+ if (bit_offset < 3) {
+ idx = (d[byte_offset] >> (2-bit_offset)) & 0x3F;
+ } else {
+ idx = (d[byte_offset] << (bit_offset-2)) & 0x3F;
+ if (byte_offset+1 < len) {
+ idx |= (d[byte_offset+1] >> (8-(bit_offset-2)));
+ }
+ }
+ out[i] = b64[idx];
+ }
+
+ while (pad && (i % 4))
+ out[i++] = '=';
+
+ out[i] = '\0';
+}
+
+/* Generate a challenge buffer and return it base64-encoded. */
+static void gen_challenge(const char *addr, char *challenge)
+{
+ char input[32];
+ char digest[MAX_DIGEST_LEN];
+ struct timeval tv;
+ int len;
+
+ memset(input, 0, sizeof input);
+
+ strlcpy(input, addr, 17);
+ sys_gettimeofday(&tv);
+ SIVAL(input, 16, tv.tv_sec);
+ SIVAL(input, 20, tv.tv_usec);
+ SIVAL(input, 24, getpid());
+
+ sum_init(0);
+ sum_update(input, sizeof input);
+ len = sum_end(digest);
+
+ base64_encode(digest, len, challenge, 0);
+}
+
+
+/* Return the secret for a user from the secret file, null terminated.
+ * Maximum length is len (not counting the null). */
+static int get_secret(int module, const char *user, char *secret, int len)
+{
+ const char *fname = lp_secrets_file(module);
+ STRUCT_STAT st;
+ int fd, ok = 1;
+ const char *p;
+ char ch, *s;
+
+ if (!fname || !*fname)
+ return 0;
+
+ if ((fd = open(fname, O_RDONLY)) < 0)
+ return 0;
+
+ if (do_stat(fname, &st) == -1) {
+ rsyserr(FLOG, errno, "stat(%s)", fname);
+ ok = 0;
+ } else if (lp_strict_modes(module)) {
+ if ((st.st_mode & 06) != 0) {
+ rprintf(FLOG, "secrets file must not be other-accessible (see strict modes option)\n");
+ ok = 0;
+ } else if (MY_UID() == 0 && st.st_uid != 0) {
+ rprintf(FLOG, "secrets file must be owned by root when running as root (see strict modes)\n");
+ ok = 0;
+ }
+ }
+ if (!ok) {
+ rprintf(FLOG, "continuing without secrets file\n");
+ close(fd);
+ return 0;
+ }
+
+ if (*user == '#') {
+ /* Reject attempt to match a comment. */
+ close(fd);
+ return 0;
+ }
+
+ /* Try to find a line that starts with the user name and a ':'. */
+ p = user;
+ while (1) {
+ if (read(fd, &ch, 1) != 1) {
+ close(fd);
+ return 0;
+ }
+ if (ch == '\n')
+ p = user;
+ else if (p) {
+ if (*p == ch)
+ p++;
+ else if (!*p && ch == ':')
+ break;
+ else
+ p = NULL;
+ }
+ }
+
+ /* Slurp the secret into the "secret" buffer. */
+ s = secret;
+ while (len > 0) {
+ if (read(fd, s, 1) != 1 || *s == '\n')
+ break;
+ if (*s == '\r')
+ continue;
+ s++;
+ len--;
+ }
+ *s = '\0';
+ close(fd);
+
+ return 1;
+}
+
+static const char *getpassf(const char *filename)
+{
+ STRUCT_STAT st;
+ char buffer[512], *p;
+ int fd, n, ok = 1;
+ const char *envpw = getenv("RSYNC_PASSWORD");
+
+ if (!filename)
+ return NULL;
+
+ if ((fd = open(filename,O_RDONLY)) < 0) {
+ rsyserr(FWARNING, errno, "could not open password file \"%s\"",
+ filename);
+ if (envpw)
+ rprintf(FINFO, "falling back to RSYNC_PASSWORD environment variable.\n");
+ return NULL;
+ }
+
+ if (do_stat(filename, &st) == -1) {
+ rsyserr(FWARNING, errno, "stat(%s)", filename);
+ ok = 0;
+ } else if ((st.st_mode & 06) != 0) {
+ rprintf(FWARNING, "password file must not be other-accessible\n");
+ ok = 0;
+ } else if (MY_UID() == 0 && st.st_uid != 0) {
+ rprintf(FWARNING, "password file must be owned by root when running as root\n");
+ ok = 0;
+ }
+ if (!ok) {
+ close(fd);
+ rprintf(FWARNING, "continuing without password file\n");
+ if (envpw)
+ rprintf(FINFO, "falling back to RSYNC_PASSWORD environment variable.\n");
+ return NULL;
+ }
+
+ n = read(fd, buffer, sizeof buffer - 1);
+ close(fd);
+ if (n > 0) {
+ buffer[n] = '\0';
+ if ((p = strtok(buffer, "\n\r")) != NULL)
+ return strdup(p);
+ }
+
+ return NULL;
+}
+
+/* Generate an MD4 hash created from the combination of the password
+ * and the challenge string and return it base64-encoded. */
+static void generate_hash(const char *in, const char *challenge, char *out)
+{
+ char buf[MAX_DIGEST_LEN];
+ int len;
+
+ sum_init(0);
+ sum_update(in, strlen(in));
+ sum_update(challenge, strlen(challenge));
+ len = sum_end(buf);
+
+ base64_encode(buf, len, out, 0);
+}
+
+/* Possibly negotiate authentication with the client. Use "leader" to
+ * start off the auth if necessary.
+ *
+ * Return NULL if authentication failed. Return "" if anonymous access.
+ * Otherwise return username.
+ */
+char *auth_server(int f_in, int f_out, int module, const char *host,
+ const char *addr, const char *leader)
+{
+ char *users = lp_auth_users(module);
+ char challenge[MAX_DIGEST_LEN*2];
+ char line[BIGPATHBUFLEN];
+ char secret[512];
+ char pass2[MAX_DIGEST_LEN*2];
+ char *tok, *pass;
+
+ /* if no auth list then allow anyone in! */
+ if (!users || !*users)
+ return "";
+
+ gen_challenge(addr, challenge);
+
+ io_printf(f_out, "%s%s\n", leader, challenge);
+
+ if (!read_line_old(f_in, line, sizeof line)
+ || (pass = strchr(line, ' ')) == NULL) {
+ rprintf(FLOG, "auth failed on module %s from %s (%s): "
+ "invalid challenge response\n",
+ lp_name(module), host, addr);
+ return NULL;
+ }
+ *pass++ = '\0';
+
+ if (!(users = strdup(users)))
+ out_of_memory("auth_server");
+
+ for (tok = strtok(users, " ,\t"); tok; tok = strtok(NULL, " ,\t")) {
+ if (wildmatch(tok, line))
+ break;
+ }
+ free(users);
+
+ if (!tok) {
+ rprintf(FLOG, "auth failed on module %s from %s (%s): "
+ "unauthorized user\n",
+ lp_name(module), host, addr);
+ return NULL;
+ }
+
+ memset(secret, 0, sizeof secret);
+ if (!get_secret(module, line, secret, sizeof secret - 1)) {
+ memset(secret, 0, sizeof secret);
+ rprintf(FLOG, "auth failed on module %s from %s (%s): "
+ "missing secret for user \"%s\"\n",
+ lp_name(module), host, addr, line);
+ return NULL;
+ }
+
+ generate_hash(secret, challenge, pass2);
+ memset(secret, 0, sizeof secret);
+
+ if (strcmp(pass, pass2) != 0) {
+ rprintf(FLOG, "auth failed on module %s from %s (%s): "
+ "password mismatch\n",
+ lp_name(module), host, addr);
+ return NULL;
+ }
+
+ return strdup(line);
+}
+
+void auth_client(int fd, const char *user, const char *challenge)
+{
+ const char *pass;
+ char pass2[MAX_DIGEST_LEN*2];
+
+ if (!user || !*user)
+ user = "nobody";
+
+ if (!(pass = getpassf(password_file))
+ && !(pass = getenv("RSYNC_PASSWORD"))) {
+ /* XXX: cyeoh says that getpass is deprecated, because
+ * it may return a truncated password on some systems,
+ * and it is not in the LSB.
+ *
+ * Andrew Klein says that getpassphrase() is present
+ * on Solaris and reads up to 256 characters.
+ *
+ * OpenBSD has a readpassphrase() that might be more suitable.
+ */
+ pass = getpass("Password: ");
+ }
+
+ if (!pass)
+ pass = "";
+
+ generate_hash(pass, challenge, pass2);
+ io_printf(fd, "%s %s\n", user, pass2);
+}
Matt McCutchen's Web Site / rsync / rsync.git / blobdiff