7 files changed, 398 insertions, 0 deletions

diff --git a/source4/lib/socket/access.c b/source4/lib/socket/access.c
new file mode 100644
index 0000000000..f33f8d56b1
--- /dev/null
+++ b/source4/lib/socket/access.c
@@ -0,0 +1,353 @@
+/* 
+   Unix SMB/CIFS implementation.
+
+   check access rules for socket connections
+
+   Copyright (C) Andrew Tridgell 2004
+   
+   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.
+*/
+
+
+/* 
+   This module is an adaption of code from the tcpd-1.4 package written
+   by Wietse Venema, Eindhoven University of Technology, The Netherlands.
+
+   The code is used here with permission.
+
+   The code has been considerably changed from the original. Bug reports
+   should be sent to samba@samba.org
+*/
+
+#include "includes.h"
+
+#define	FAIL		(-1)
+#define ALLONES  ((uint32_t)0xFFFFFFFF)
+
+/* masked_match - match address against netnumber/netmask */
+static BOOL masked_match(TALLOC_CTX *mem_ctx, const char *tok, const char *slash, const char *s)
+{
+	uint32_t net;
+	uint32_t mask;
+	uint32_t addr;
+	char *tok_cpy;
+
+	if ((addr = interpret_addr(s)) == INADDR_NONE)
+		return False;
+
+	tok_cpy = talloc_strdup(mem_ctx, tok);
+	tok_cpy[PTR_DIFF(slash,tok)] = '\0';
+	net = interpret_addr(tok_cpy);
+	talloc_free(tok_cpy);
+
+        if (strlen(slash + 1) > 2) {
+                mask = interpret_addr(slash + 1);
+        } else {
+		mask = (uint32_t)((ALLONES >> atoi(slash + 1)) ^ ALLONES);
+		/* convert to network byte order */
+		mask = htonl(mask);
+        }
+
+	if (net == INADDR_NONE || mask == INADDR_NONE) {
+		DEBUG(0,("access: bad net/mask access control: %s\n", tok));
+		return False;
+	}
+	
+	return (addr & mask) == (net & mask);
+}
+
+/* string_match - match string against token */
+static BOOL string_match(TALLOC_CTX *mem_ctx, const char *tok,const char *s, char *invalid_char)
+{
+	size_t     tok_len;
+	size_t     str_len;
+	const char   *cut;
+
+	*invalid_char = '\0';
+
+	/* Return True if a token has the magic value "ALL". Return
+	 * FAIL if the token is "FAIL". If the token starts with a "."
+	 * (domain name), return True if it matches the last fields of
+	 * the string. If the token has the magic value "LOCAL",
+	 * return True if the string does not contain a "."
+	 * character. If the token ends on a "." (network number),
+	 * return True if it matches the first fields of the
+	 * string. If the token begins with a "@" (netgroup name),
+	 * return True if the string is a (host) member of the
+	 * netgroup. Return True if the token fully matches the
+	 * string. If the token is a netnumber/netmask pair, return
+	 * True if the address is a member of the specified subnet.  
+	 */
+
+	if (tok[0] == '.') {			/* domain: match last fields */
+		if ((str_len = strlen(s)) > (tok_len = strlen(tok))
+		    && strcasecmp(tok, s + str_len - tok_len)==0) {
+			return True;
+		}
+	} else if (tok[0] == '@') { /* netgroup: look it up */
+		DEBUG(0,("access: netgroup support is not available\n"));
+		return False;
+	} else if (strcmp(tok, "ALL")==0) {	/* all: match any */
+		return True;
+	} else if (strcmp(tok, "FAIL")==0) {	/* fail: match any */
+		return FAIL;
+	} else if (strcmp(tok, "LOCAL")==0) {	/* local: no dots */
+		if (strchr(s, '.') == 0 && strcasecmp(s, "unknown") != 0) {
+			return True;
+		}
+	} else if (strcasecmp(tok, s)==0) {   /* match host name or address */
+		return True;
+	} else if (tok[(tok_len = strlen(tok)) - 1] == '.') {	/* network */
+		if (strncmp(tok, s, tok_len) == 0)
+			return True;
+	} else if ((cut = strchr(tok, '/')) != 0) {	/* netnumber/netmask */
+		if (isdigit((int)s[0]) && masked_match(mem_ctx, tok, cut, s))
+			return True;
+	} else if (strchr(tok, '*') != 0) {
+		*invalid_char = '*';
+	} else if (strchr(tok, '?') != 0) {
+		*invalid_char = '?';
+	}
+	return False;
+}
+
+struct client_addr {
+	const char *cname;
+	const char *caddr;
+};
+
+/* client_match - match host name and address against token */
+static BOOL client_match(TALLOC_CTX *mem_ctx, const char *tok, struct client_addr *client)
+{
+	BOOL match;
+	char invalid_char = '\0';
+
+	/*
+	 * Try to match the address first. If that fails, try to match the host
+	 * name if available.
+	 */
+
+	if ((match = string_match(mem_ctx, tok, client->caddr, &invalid_char)) == 0) {
+		if(invalid_char)
+			DEBUG(0,("client_match: address match failing due to invalid character '%c' found in \
+token '%s' in an allow/deny hosts line.\n", invalid_char, tok ));
+
+		if (client->cname[0] != 0)
+			match = string_match(mem_ctx, tok, client->cname, &invalid_char);
+
+		if(invalid_char)
+			DEBUG(0,("client_match: address match failing due to invalid character '%c' found in \
+token '%s' in an allow/deny hosts line.\n", invalid_char, tok ));
+	}
+
+	return (match);
+}
+
+/* list_match - match an item against a list of tokens with exceptions */
+static BOOL list_match(TALLOC_CTX *mem_ctx, const char **list, struct client_addr *client)
+{
+	BOOL match = False;
+
+	if (!list)
+		return False;
+
+	/*
+	 * Process tokens one at a time. We have exhausted all possible matches
+	 * when we reach an "EXCEPT" token or the end of the list. If we do find
+	 * a match, look for an "EXCEPT" list and recurse to determine whether
+	 * the match is affected by any exceptions.
+	 */
+
+	for (; *list ; list++) {
+		if (strcmp(*list, "EXCEPT")==0)	/* EXCEPT: give up */
+			break;
+		if ((match = client_match(mem_ctx, *list, client)))	/* True or FAIL */
+			break;
+	}
+
+	/* Process exceptions to True or FAIL matches. */
+	if (match != False) {
+		while (*list  && strcmp(*list, "EXCEPT")!=0)
+			list++;
+
+		for (; *list; list++) {
+			if (client_match(mem_ctx, *list, client)) /* Exception Found */
+				return False;
+		}
+	}
+
+	return match;
+}
+
+/* return true if access should be allowed */
+static BOOL allow_access_internal(TALLOC_CTX *mem_ctx,
+				  const char **deny_list,const char **allow_list,
+				  const char *cname, const char *caddr)
+{
+	struct client_addr client;
+
+	client.cname = cname;
+	client.caddr = caddr;
+
+	/* if it is loopback then always allow unless specifically denied */
+	if (strcmp(caddr, "127.0.0.1") == 0) {
+		/*
+		 * If 127.0.0.1 matches both allow and deny then allow.
+		 * Patch from Steve Langasek vorlon@netexpress.net.
+		 */
+		if (deny_list && 
+			list_match(mem_ctx, deny_list, &client) &&
+				(!allow_list ||
+				!list_match(mem_ctx, allow_list, &client))) {
+			return False;
+		}
+		return True;
+	}
+
+	/* if theres no deny list and no allow list then allow access */
+	if ((!deny_list || *deny_list == 0) && 
+	    (!allow_list || *allow_list == 0)) {
+		return True;  
+	}
+
+	/* if there is an allow list but no deny list then allow only hosts
+	   on the allow list */
+	if (!deny_list || *deny_list == 0)
+		return list_match(mem_ctx, allow_list, &client);
+
+	/* if theres a deny list but no allow list then allow
+	   all hosts not on the deny list */
+	if (!allow_list || *allow_list == 0)
+		return !list_match(mem_ctx, deny_list, &client);
+
+	/* if there are both types of list then allow all hosts on the
+           allow list */
+	if (list_match(mem_ctx, allow_list, &client))
+		return True;
+
+	/* if there are both types of list and it's not on the allow then
+	   allow it if its not on the deny */
+	if (list_match(mem_ctx, deny_list, &client))
+		return False;
+	
+	return True;
+}
+
+/* return true if access should be allowed */
+static BOOL allow_access(TALLOC_CTX *mem_ctx,
+			 const char **deny_list, const char **allow_list,
+			 const char *cname, const char *caddr)
+{
+	BOOL ret;
+	char *nc_cname = talloc_strdup(mem_ctx, cname);
+	char *nc_caddr = talloc_strdup(mem_ctx, caddr);
+
+	if (!nc_cname || !nc_caddr) {
+		return False;
+	}
+	
+	ret = allow_access_internal(mem_ctx, deny_list, allow_list, nc_cname, nc_caddr);
+
+	talloc_free(nc_cname);
+	talloc_free(nc_caddr);
+
+	return ret;
+}
+
+/* return true if the char* contains ip addrs only.  Used to avoid 
+gethostbyaddr() calls */
+
+static BOOL only_ipaddrs_in_list(const char** list)
+{
+	BOOL only_ip = True;
+	
+	if (!list)
+		return True;
+			
+	for (; *list ; list++) {
+		/* factor out the special strings */
+		if (strcmp(*list, "ALL")==0 || 
+		    strcmp(*list, "FAIL")==0 || 
+		    strcmp(*list, "EXCEPT")==0) {
+			continue;
+		}
+		
+		if (!is_ipaddress(*list)) {
+			/* 
+			 * if we failed, make sure that it was not because the token
+			 * was a network/netmask pair.  Only network/netmask pairs
+			 * have a '/' in them
+			 */
+			if ((strchr(*list, '/')) == NULL) {
+				only_ip = False;
+				DEBUG(3,("only_ipaddrs_in_list: list has non-ip address (%s)\n", *list));
+				break;
+			}
+		}
+	}
+	
+	return only_ip;
+}
+
+/* return true if access should be allowed to a service for a socket */
+BOOL socket_check_access(struct socket_context *sock, 
+			 const char *service_name,
+			 const char **allow_list, const char **deny_list)
+{
+	BOOL ret;
+	const char *name="", *addr;
+	TALLOC_CTX *mem_ctx;
+
+	if ((!deny_list  || *deny_list==0) && 
+	    (!allow_list || *allow_list==0)) {
+		return True;
+	}
+
+	mem_ctx = talloc_init("socket_check_access");
+	if (!mem_ctx) {
+		return False;
+	}
+
+	addr = socket_get_peer_addr(sock, mem_ctx);
+
+	/* bypass gethostbyaddr() calls if the lists only contain IP addrs */
+	if (!only_ipaddrs_in_list(allow_list) || 
+	    !only_ipaddrs_in_list(deny_list)) {
+		name = socket_get_peer_name(sock, mem_ctx);
+		if (!name) {
+			name = addr;
+		}
+	}
+
+	if (!addr) {
+		DEBUG(0,("socket_check_access: Denied connection from unknown host\n"));
+		talloc_free(mem_ctx);
+		return False;
+	}
+
+	ret = allow_access(mem_ctx, deny_list, allow_list, name, addr);
+	
+	if (ret) {
+		DEBUG(2,("socket_check_access: Allowed connection to '%s' from %s (%s)\n", 
+			 service_name, name, addr));
+	} else {
+		DEBUG(0,("socket_check_access: Denied connection to '%s' from %s (%s)\n", 
+			 service_name, name, addr));
+	}
+
+	talloc_free(mem_ctx);
+
+	return ret;
+}
diff --git a/source4/lib/socket/config.mk b/source4/lib/socket/config.mk
index 854702a6f8..320fc7f3ee 100644
--- a/source4/lib/socket/config.mk
+++ b/source4/lib/socket/config.mk
@@ -12,5 +12,7 @@ INIT_OBJ_FILES = \
 [SUBSYSTEM::SOCKET]
 INIT_OBJ_FILES = \
 		lib/socket/socket.o
+ADD_OBJ_FILES = \
+		lib/socket/access.o
 # End SUBSYSTEM SOCKET
 ################################################
diff --git a/source4/lib/socket/socket.c b/source4/lib/socket/socket.c
index 6869114587..4814cc6a5a 100644
--- a/source4/lib/socket/socket.c
+++ b/source4/lib/socket/socket.c
@@ -160,6 +160,15 @@ NTSTATUS socket_set_option(struct socket_context *sock, const char *option, cons
 	return sock->ops->set_option(sock, option, val);
 }
 
+char *socket_get_peer_name(struct socket_context *sock, TALLOC_CTX *mem_ctx)
+{
+	if (!sock->ops->get_peer_name) {
+		return NULL;
+	}
+
+	return sock->ops->get_peer_name(sock, mem_ctx);
+}
+
 char *socket_get_peer_addr(struct socket_context *sock, TALLOC_CTX *mem_ctx)
 {
 	if (!sock->ops->get_peer_addr) {
diff --git a/source4/lib/socket/socket.h b/source4/lib/socket/socket.h
index ea4de1d291..a089a1b78a 100644
--- a/source4/lib/socket/socket.h
+++ b/source4/lib/socket/socket.h
@@ -55,6 +55,7 @@ struct socket_ops {
 
 	NTSTATUS (*set_option)(struct socket_context *sock, const char *option, const char *val);
 
+	char *(*get_peer_name)(struct socket_context *sock, TALLOC_CTX *mem_ctx);
 	char *(*get_peer_addr)(struct socket_context *sock, TALLOC_CTX *mem_ctx);
 	int (*get_peer_port)(struct socket_context *sock);
 	char *(*get_my_addr)(struct socket_context *sock, TALLOC_CTX *mem_ctx);
diff --git a/source4/lib/socket/socket_ipv4.c b/source4/lib/socket/socket_ipv4.c
index 9a1e7e43f6..151c49518f 100644
--- a/source4/lib/socket/socket_ipv4.c
+++ b/source4/lib/socket/socket_ipv4.c
@@ -293,6 +293,26 @@ static NTSTATUS ipv4_tcp_set_option(struct socket_context *sock, const char *opt
 	return NT_STATUS_OK;
 }
 
+static char *ipv4_tcp_get_peer_name(struct socket_context *sock, TALLOC_CTX *mem_ctx)
+{
+	struct sockaddr_in peer_addr;
+	socklen_t len = sizeof(peer_addr);
+	struct hostent *he;
+	int ret;
+
+	ret = getpeername(sock->fd, (struct sockaddr *)&peer_addr, &len);
+	if (ret == -1) {
+		return NULL;
+	}
+
+	he = gethostbyaddr((char *)&peer_addr.sin_addr, sizeof(peer_addr.sin_addr), AF_INET);
+	if (he == NULL) {
+		return NULL;
+	}
+
+	return talloc_strdup(mem_ctx, he->h_name);
+}
+
 static char *ipv4_tcp_get_peer_addr(struct socket_context *sock, TALLOC_CTX *mem_ctx)
 {
 	struct sockaddr_in peer_addr;
@@ -368,6 +388,7 @@ static const struct socket_ops ipv4_tcp_ops = {
 
 	.set_option	= ipv4_tcp_set_option,
 
+	.get_peer_name	= ipv4_tcp_get_peer_name,
 	.get_peer_addr	= ipv4_tcp_get_peer_addr,
 	.get_peer_port	= ipv4_tcp_get_peer_port,
 	.get_my_addr	= ipv4_tcp_get_my_addr,
diff --git a/source4/smb_server/service.c b/source4/smb_server/service.c
index bc436172a1..5f698fe20b 100644
--- a/source4/smb_server/service.c
+++ b/source4/smb_server/service.c
@@ -143,6 +143,13 @@ static NTSTATUS make_connection_snum(struct smbsrv_request *req,
 	struct smbsrv_tcon *tcon;
 	NTSTATUS status;
 
+	if (!socket_check_access(req->smb_conn->connection->socket, 
+				 lp_servicename(snum), 
+				 lp_hostsallow(snum), 
+				 lp_hostsdeny(snum))) {
+		return NT_STATUS_ACCESS_DENIED;
+	}
+
 	tcon = conn_new(req->smb_conn);
 	if (!tcon) {
 		DEBUG(0,("Couldn't find free connection.\n"));
diff --git a/source4/smbd/service.c b/source4/smbd/service.c
index 323bc62a85..278a763657 100644
--- a/source4/smbd/service.c
+++ b/source4/smbd/service.c
@@ -226,6 +226,11 @@ struct server_connection *server_setup_connection(struct event_context *ev, stru
 	srv_conn->event.fde	= event_add_fd(ev,&fde);
 	srv_conn->event.idle	= event_add_timed(ev,&idle);
 
+	if (!socket_check_access(sock, "smbd", lp_hostsallow(-1), lp_hostsdeny(-1))) {
+		server_terminate_connection(srv_conn, "denied by access rules");
+		return NULL;
+	}
+
 	return srv_conn;
 }