X-Git-Url: https://mattmccutchen.net/rsync/rsync.git/blobdiff_plain/30c041f9adc3468805e696753e21955d3c68b9e6..28b519c93b6db30b6520d46f8cd65160213fddd2:/authenticate.c

diff --git a/authenticate.c b/authenticate.c
index 542f4403..76b3cc05 100644
--- a/authenticate.c
+++ b/authenticate.c
@@ -1,41 +1,40 @@
-/* -*- c-file-style: "linux"; -*-
-
-   Copyright (C) 1998-2000 by Andrew Tridgell
-
-   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 daemon authentication.
+ *
+ * Copyright (C) 1998-2000 Andrew Tridgell
+ * Copyright (C) 2002-2009 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.
+ */
 
-/* support rsync authentication */
 #include "rsync.h"
+#include "itypes.h"
 
+extern int read_only;
 extern char *password_file;
-extern int am_root;
 
 /***************************************************************************
 encode a buffer using base64 - simple and slow algorithm. null terminates
 the result.
   ***************************************************************************/
-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++) {
 		byte_offset = (i*6)/8;
 		bit_offset = (i*6)%8;
@@ -49,17 +48,24 @@ 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);
 
-	strlcpy((char *)input, addr, 17);
+	strlcpy(input, addr, 17);
 	sys_gettimeofday(&tv);
 	SIVAL(input, 16, tv.tv_sec);
 	SIVAL(input, 20, tv.tv_usec);
@@ -67,122 +73,135 @@ static void gen_challenge(char *addr, char *challenge)
 
 	sum_init(0);
 	sum_update(input, sizeof input);
-	sum_end(challenge);
+	len = sum_end(digest);
+
+	base64_encode(digest, len, challenge, 0);
 }
 
+/* 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);
+}
 
 /* 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, char *user, char *secret, int len)
+static const char *check_secret(int module, const char *user, const char *group,
+				const char *challenge, const char *pass)
 {
-	char *fname = lp_secrets_file(module);
+	char line[1024];
+	char pass2[MAX_DIGEST_LEN*2];
+	const char *fname = lp_secrets_file(module);
 	STRUCT_STAT st;
 	int fd, ok = 1;
-	char ch, *p;
-
-	if (!fname || !*fname)
-		return 0;
+	int user_len = strlen(user);
+	int group_len = group ? strlen(group) : 0;
+	char *err;
 
-	if ((fd = open(fname, O_RDONLY)) < 0)
-		return 0;
+	if (!fname || !*fname || (fd = open(fname, O_RDONLY)) < 0)
+		return "no secrets file";
 
-	if (do_stat(fname, &st) == -1) {
-		rsyserr(FLOG, errno, "stat(%s)", fname);
+	if (do_fstat(fd, &st) == -1) {
+		rsyserr(FLOG, errno, "fstat(%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 (am_root && (st.st_uid != 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;
+		return "ignoring secrets file";
 	}
 
 	if (*user == '#') {
 		/* Reject attempt to match a comment. */
 		close(fd);
-		return 0;
+		return "invalid username";
 	}
 
-	/* 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;
+	/* Try to find a line that starts with the user (or @group) name and a ':'. */
+	err = "secret not found";
+	while ((user || group) && read_line_old(fd, line, sizeof line, 1)) {
+		const char **ptr, *s;
+		int len;
+		if (*line == '@') {
+			ptr = &group;
+			len = group_len;
+			s = line+1;
+		} else {
+			ptr = &user;
+			len = user_len;
+			s = line;
 		}
-		if (ch == '\n')
-			p = user;
-		else if (p) {
-			if (*p == ch)
-				p++;
-			else if (!*p && ch == ':')
-				break;
-			else
-				p = NULL;
+		if (!*ptr || strncmp(s, *ptr, len) != 0 || s[len] != ':')
+			continue;
+		generate_hash(s+len+1, challenge, pass2);
+		if (strcmp(pass, pass2) == 0) {
+			err = NULL;
+			break;
 		}
+		err = "password mismatch";
+		*ptr = NULL; /* Don't look for name again. */
 	}
 
-	/* Slurp the secret into the "secret" buffer. */
-	p = secret;
-	while (len > 0) {
-		if (read(fd, p, 1) != 1 || *p == '\n')
-			break;
-		if (*p == '\r')
-			continue;
-		p++;
-		len--;
-	}
-	*p = '\0';
 	close(fd);
 
-	return 1;
+	memset(line, 0, sizeof line);
+	memset(pass2, 0, sizeof pass2);
+
+	return err;
 }
 
-static char *getpassf(char *filename)
+static const char *getpassf(const char *filename)
 {
 	STRUCT_STAT st;
 	char buffer[512], *p;
 	int fd, n, ok = 1;
-	char *envpw = getenv("RSYNC_PASSWORD");
+	const char *envpw = getenv("RSYNC_PASSWORD");
 
 	if (!filename)
 		return NULL;
 
 	if ((fd = open(filename,O_RDONLY)) < 0) {
-		rsyserr(FERROR, errno, "could not open password file \"%s\"",filename);
+		rsyserr(FWARNING, errno, "could not open password file \"%s\"",
+			filename);
 		if (envpw)
-			rprintf(FERROR, "falling back to RSYNC_PASSWORD environment variable.\n");
+			rprintf(FINFO, "falling back to RSYNC_PASSWORD environment variable.\n");
 		return NULL;
 	}
 
 	if (do_stat(filename, &st) == -1) {
-		rsyserr(FERROR, errno, "stat(%s)", filename);
+		rsyserr(FWARNING, errno, "stat(%s)", filename);
 		ok = 0;
 	} else if ((st.st_mode & 06) != 0) {
-		rprintf(FERROR,"password file must not be other-accessible\n");
+		rprintf(FWARNING, "password file must not be other-accessible\n");
 		ok = 0;
-	} else if (am_root && st.st_uid != 0) {
-		rprintf(FERROR,"password file must be owned by root when running as root\n");
+	} 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) {
-		rprintf(FERROR,"continuing without password file\n");
-		if (envpw)
-			rprintf(FERROR, "using RSYNC_PASSWORD environment variable.\n");
 		close(fd);
+		rprintf(FWARNING, "continuing without password file\n");
+		if (envpw)
+			rprintf(FINFO, "falling back to RSYNC_PASSWORD environment variable.\n");
 		return NULL;
 	}
 
-	if (envpw)
-		rprintf(FERROR, "RSYNC_PASSWORD environment variable ignored\n");
-
 	n = read(fd, buffer, sizeof buffer - 1);
 	close(fd);
 	if (n > 0) {
@@ -194,36 +213,24 @@ static char *getpassf(char *filename)
 	return NULL;
 }
 
-/* generate a 16 byte hash from a password and challenge */
-static void generate_hash(char *in, char *challenge, char *out)
-{
-	char buf[16];
-
-	sum_init(0);
-	sum_update(in, strlen(in));
-	sum_update(challenge, strlen(challenge));
-	sum_end(buf);
-
-	base64_encode(buf, 16, out);
-}
-
 /* 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, char *addr, char *leader)
+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];
-	static char user[100];
-	char secret[100];
-	char pass[30];
-	char pass2[30];
-	char *tok;
+	char challenge[MAX_DIGEST_LEN*2];
+	char line[BIGPATHBUFLEN];
+	char **auth_uid_groups = NULL;
+	int auth_uid_groups_cnt = -1;
+	const char *err = NULL;
+	int group_match = -1;
+	char *tok, *pass;
+	char opt_ch = '\0';
 
 	/* if no auth list then allow anyone in! */
 	if (!users || !*users)
@@ -231,52 +238,114 @@ char *auth_server(int f_in, int f_out, int module, char *addr, char *leader)
 
 	gen_challenge(addr, challenge);
 
-	base64_encode(challenge, 16, b64_challenge);
-
-	io_printf(f_out, "%s%s\n", leader, b64_challenge);
+	io_printf(f_out, "%s%s\n", leader, challenge);
 
-	if (!read_line(f_in, line, sizeof line - 1))
+	if (!read_line_old(f_in, line, sizeof line, 0)
+	 || (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")) {
+		char *opts;
+		/* See if the user appended :deny, :ro, or :rw. */
+		if ((opts = strchr(tok, ':')) != NULL) {
+			*opts++ = '\0';
+			opt_ch = isUpper(opts) ? toLower(opts) : *opts;
+			if (opt_ch == 'r') { /* handle ro and rw */
+				opt_ch = isUpper(opts+1) ? toLower(opts+1) : opts[1];
+				if (opt_ch == 'o')
+					opt_ch = 'r';
+				else if (opt_ch != 'w')
+					opt_ch = '\0';
+			} else if (opt_ch != 'd') /* if it's not deny, ignore it */
+				opt_ch = '\0';
+		} else
+			opt_ch = '\0';
+		if (*tok != '@') {
+			/* Match the username */
+			if (wildmatch(tok, line))
+				break;
+		} else {
+#ifdef HAVE_GETGROUPLIST
+			int j;
+			/* See if authorizing user is a real user, and if so, see
+			 * if it is in a group that matches tok+1 wildmat. */
+			if (auth_uid_groups_cnt < 0) {
+				gid_t gid_list[64];
+				uid_t auth_uid;
+				auth_uid_groups_cnt = sizeof gid_list / sizeof (gid_t);
+				if (!user_to_uid(line, &auth_uid, False)
+				 || getallgroups(auth_uid, gid_list, &auth_uid_groups_cnt) != NULL)
+					auth_uid_groups_cnt = 0;
+				else {
+					if ((auth_uid_groups = new_array(char *, auth_uid_groups_cnt)) == NULL)
+						out_of_memory("auth_server");
+					for (j = 0; j < auth_uid_groups_cnt; j++)
+						auth_uid_groups[j] = gid_to_group(gid_list[j]);
+				}
+			}
+			for (j = 0; j < auth_uid_groups_cnt; j++) {
+				if (auth_uid_groups[j] && wildmatch(tok+1, auth_uid_groups[j])) {
+					group_match = j;
+					break;
+				}
+			}
+			if (group_match >= 0)
+				break;
+#else
+			rprintf(FLOG, "your computer doesn't support getgrouplist(), so no @group authorization is possible.\n");
+#endif
+		}
+	}
 
-	memset(user, 0, sizeof user);
-	memset(pass, 0, sizeof pass);
+	free(users);
 
-	if (sscanf(line,"%99s %29s", user, pass) != 2)
-		return NULL;
+	if (!tok)
+		err = "no matching rule";
+	else if (opt_ch == 'd')
+		err = "denied by rule";
+	else {
+		char *group = group_match >= 0 ? auth_uid_groups[group_match] : NULL;
+		err = check_secret(module, line, group, challenge, pass);
+	}
 
-	users = strdup(users);
-	if (!users)
-		return NULL;
+	memset(challenge, 0, sizeof challenge);
+	memset(pass, 0, strlen(pass));
 
-	for (tok=strtok(users," ,\t"); tok; tok = strtok(NULL," ,\t")) {
-		if (wildmatch(tok, user))
-			break;
+	if (auth_uid_groups) {
+		int j;
+		for (j = 0; j < auth_uid_groups_cnt; j++) {
+			if (auth_uid_groups[j])
+				free(auth_uid_groups[j]);
+		}
+		free(auth_uid_groups);
 	}
-	free(users);
 
-	if (!tok)
-		return NULL;
-
-	memset(secret, 0, sizeof secret);
-	if (!get_secret(module, user, secret, sizeof secret - 1)) {
-		memset(secret, 0, sizeof secret);
+	if (err) {
+		rprintf(FLOG, "auth failed on module %s from %s (%s) for %s: %s\n",
+			lp_name(module), host, addr, line, err);
 		return NULL;
 	}
 
-	generate_hash(secret, b64_challenge, pass2);
-	memset(secret, 0, sizeof secret);
-
-	if (strcmp(pass, pass2) == 0)
-		return user;
+	if (opt_ch == 'r')
+		read_only = 1;
+	else if (opt_ch == 'w')
+		read_only = 0;
 
-	return NULL;
+	return strdup(line);
 }
 
-
-void auth_client(int fd, char *user, char *challenge)
+void auth_client(int fd, const char *user, const char *challenge)
 {
-	char *pass;
-	char pass2[30];
+	const char *pass;
+	char pass2[MAX_DIGEST_LEN*2];
 
 	if (!user || !*user)
 		user = "nobody";
@@ -301,5 +370,3 @@ void auth_client(int fd, char *user, char *challenge)
 	generate_hash(pass, challenge, pass2);
 	io_printf(fd, "%s %s\n", user, pass2);
 }
-
-