X-Git-Url: https://mattmccutchen.net/rsync/rsync.git/blobdiff_plain/e42c9458c2f1e3a78d6d45e99741d6edb38fc0cc..3f0211b63a6cdc4a2cecfd2a0dffeba172c86a47:/authenticate.c

diff --git a/authenticate.c b/authenticate.c
index 351c8a0a..dd74b684 100644
--- a/authenticate.c
+++ b/authenticate.c
@@ -1,38 +1,39 @@
-/* 
-   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) 2002-2007 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.
   ***************************************************************************/
-static void base64_encode(char *buf, int len, char *out)
+void base64_encode(const char *buf, int len, char *out, int pad)
 {
 	char *b64 = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
 	int bit_offset, byte_offset, idx, i;
-	unsigned char *d = (unsigned char *)buf;
+	const uchar *d = (const uchar *)buf;
 	int bytes = (len*8 + 5)/6;
 
-	memset(out, 0, bytes+1);
-
-	for (i=0;i<bytes;i++) {
+	for (i = 0; i < bytes; i++) {
 		byte_offset = (i*6)/8;
 		bit_offset = (i*6)%8;
 		if (bit_offset < 3) {
@@ -45,166 +46,270 @@ static void base64_encode(char *buf, int len, char *out)
 		}
 		out[i] = b64[idx];
 	}
+
+	while (pad && (i % 4))
+		out[i++] = '=';
+
+	out[i] = '\0';
 }
 
-/* create a 16 byte challenge buffer */
-static void gen_challenge(char *addr, char *challenge)
+/* 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));
+	memset(input, 0, sizeof input);
 
-	strlcpy((char *)input, addr, 16);
-	gettimeofday(&tv, NULL);
+	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();
-	sum_update(input, sizeof(input));
-	sum_end(challenge);
+	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 sercret file. maximum length
-   is len. null terminate it */
-static int get_secret(int module, char *user, char *secret, int len)
+/* 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)
 {
-	char *fname = lp_secrets_file(module);
-	int fd, found=0;
-	char line[MAXPATHLEN];
-	char *p, *pass=NULL;
-
-	if (!fname || !*fname) return 0;
-
-	fd = open(fname,O_RDONLY);
-	if (fd == -1) return 0;
-
-	while (!found) {
-		int i = 0;
-		memset(line, 0, sizeof(line));
-		while (i<(sizeof(line)-1)) {
-			if (read(fd, &line[i], 1) != 1) {
-				memset(line, 0, sizeof(line));
-				close(fd);
-				return 0;
-			}
-			if (line[i] == '\r') continue;
-			if (line[i] == '\n') break;
-			i++;
+	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;
 		}
-		line[i] = 0;
-		if (line[0] == '#') continue;
-		p = strchr(line,':');
-		if (!p) continue;
-		*p = 0;
-		if (strcmp(user, line)) continue;
-		pass = p+1;
-		found = 1;
+	}
+	if (!ok) {
+		rprintf(FLOG, "continuing without secrets file\n");
+		close(fd);
+		return 0;
 	}
 
-	close(fd);
-	if (!found) return 0;
-
-	if (strlen(pass) > len-1) {
-		memset(line, 0, sizeof(line));
+	if (*user == '#') {
+		/* Reject attempt to match a comment. */
+		close(fd);
 		return 0;
 	}
 
-	strcpy(secret, pass);
+	/* 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;
 }
 
-/* generate a 16 byte hash from a password and challenge */
-void generate_hash(char *in, char *challenge, char *out)
+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[16];
+	char buf[MAX_DIGEST_LEN];
+	int len;
 
-	sum_init();
+	sum_init(0);
 	sum_update(in, strlen(in));
 	sum_update(challenge, strlen(challenge));
-	sum_end(buf);
+	len = sum_end(buf);
 
-	base64_encode(buf, 16, out);
+	base64_encode(buf, len, out, 0);
 }
 
-/* possible negotiate authentication with the client. Use "leader" to
-   start off the auth if necessary */
-int auth_server(int fd, int module, char *addr, char *leader)
+/* 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[16];
-	char b64_challenge[30];
-	char line[MAXPATHLEN];
-	char user[100];
-	char secret[100];
-	char pass[30];
-	char pass2[30];
-	char *tok;
+	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 1;
+	if (!users || !*users)
+		return "";
 
 	gen_challenge(addr, challenge);
-	
-	base64_encode(challenge, 16, b64_challenge);
 
-	io_printf(fd,"%s%s\n", leader, b64_challenge);
+	io_printf(f_out, "%s%s\n", leader, challenge);
 
-	if (!read_line(fd, line, sizeof(line)-1)) {
-		return 0;
+	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';
 
-	memset(user, 0, sizeof(user));
-	memset(pass, 0, sizeof(pass));
+	if (!(users = strdup(users)))
+		out_of_memory("auth_server");
 
-	if (sscanf(line,"%99s %29s", user, pass) != 2) {
-		return 0;
-	}
-
-	users = strdup(users);
-	if (!users) return 0;
-
-	for (tok=strtok(users," ,\t"); tok; tok = strtok(NULL," ,\t")) {
-		if (strcmp(tok, user) == 0) break;
+	for (tok = strtok(users, " ,\t"); tok; tok = strtok(NULL, " ,\t")) {
+		if (wildmatch(tok, line))
+			break;
 	}
 	free(users);
 
 	if (!tok) {
-		return 0;
-	}
-	
-	memset(secret, 0, sizeof(secret));
-	if (!get_secret(module, user, secret, sizeof(secret)-1)) {
-		memset(secret, 0, sizeof(secret));
-		return 0;
+		rprintf(FLOG, "auth failed on module %s from %s (%s): "
+			"unauthorized user\n",
+			lp_name(module), host, addr);
+		return NULL;
 	}
 
-	generate_hash(secret, b64_challenge, pass2);
-	memset(secret, 0, sizeof(secret));
-	
-	return (strcmp(pass, pass2) == 0);
-}
+	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);
 
-void auth_client(int fd, char *user, char *challenge)
-{
-	char *pass;
-	char pass2[30];
+	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;
+	}
 
-	if (!user || !*user) return;
+	return strdup(line);
+}
 
-	if (!(pass=getenv("RSYNC_PASSWORD"))) {
+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) {
+	if (!pass)
 		pass = "";
-	}
 
 	generate_hash(pass, challenge, pass2);
-	
 	io_printf(fd, "%s %s\n", user, pass2);
 }
-