1 files changed, 349 insertions, 0 deletions
diff --git a/source4/passdb/privileges.c b/source4/passdb/privileges.c
new file mode 100644
index 0000000000..c90bc47d31
--- /dev/null
+++ b/source4/passdb/privileges.c
@@ -0,0 +1,349 @@
+/*
+ * Unix SMB/CIFS implementation. 
+ *
+ * default privileges backend for passdb
+ *
+ * Copyright (C) Andrew Tridgell 2003
+ * 
+ * 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.
+ */
+
+#include "includes.h"
+
+/*
+  this is a local implementation of a privileges backend, with
+  privileges stored in a tdb. Most passdb implementations will
+  probably use this backend, although some (such as pdb_ldap) will
+  store the privileges in another manner.
+
+  The basic principle is that the backend should store a list of SIDs
+  associated with each right, where a right is a string name such as
+  'SeTakeOwnershipPrivilege'. The SIDs can be of any type, and do not
+  need to belong to the local domain.
+
+  The way this is used is that certain places in the code which
+  require access control will ask the privileges backend 'does this
+  user have the following privilege'. The 'user' will be a NT_TOKEN,
+  which is essentially just a list of SIDs. If any of those SIDs are
+  listed in the list of SIDs for that privilege then the answer will
+  be 'yes'. That will usually mean that the user gets unconditional
+  access to that functionality, regradless of any ACLs. In this way
+  privileges act in a similar fashion to unix setuid bits.
+*/
+
+/*
+  The terms 'right' and 'privilege' are used interchangably in this
+  file. This follows MSDN convention where the LSA calls are calls on
+  'rights', which really means privileges. My apologies for the
+  confusion.
+*/
+
+
+/* 15 seconds seems like an ample time for timeouts on the privileges db */
+#define LOCK_TIMEOUT 15
+
+
+/* the tdb handle for the privileges database */
+static TDB_CONTEXT *tdb;
+
+
+/* initialise the privilege database */
+BOOL privilege_init(void)
+{
+	TALLOC_CTX *mem_ctx;
+	
+	mem_ctx = talloc_init("privilege_init talloc");
+	if (!mem_ctx) {
+		DEBUG(0,("No memory to open privilege database\n"));
+		return False;
+	}
+	tdb = tdb_open_log(lock_path(mem_ctx, "privilege.tdb"), 0, TDB_DEFAULT, 
+			   O_RDWR|O_CREAT, 0600);
+	talloc_destroy(mem_ctx);
+	if (!tdb) {
+		DEBUG(0,("Failed to open privilege database\n"));
+		return False;
+	}
+
+	return True;
+}
+
+/* 
+   lock the record for a particular privilege (write lock)
+*/
+static NTSTATUS privilege_lock_right(const char *right) 
+{
+	if (tdb_lock_bystring(tdb, right, LOCK_TIMEOUT) != 0) {
+		return NT_STATUS_INTERNAL_ERROR;
+	}
+	return NT_STATUS_OK;
+}
+
+/* 
+   unlock the record for a particular privilege (write lock)
+*/
+static void privilege_unlock_right(const char *right) 
+{
+	tdb_unlock_bystring(tdb, right);
+}
+
+
+/* 
+   return a list of SIDs that have a particular right
+*/
+NTSTATUS privilege_enum_account_with_right(const char *right, 
+					   uint32 *count, 
+					   DOM_SID **sids)
+{
+	TDB_DATA data;
+	char *p;
+	int i;
+
+	if (!tdb) {
+		return NT_STATUS_INTERNAL_ERROR;
+	}
+
+	data = tdb_fetch_by_string(tdb, right);
+	if (!data.dptr) {
+		*count = 0;
+		*sids = NULL;
+		return NT_STATUS_OK;
+	}
+
+	/* count them */
+	for (i=0, p=data.dptr; p<data.dptr+data.dsize; i++) {
+		p += strlen(p) + 1;
+	}
+	*count = i;
+
+	/* allocate and parse */
+	*sids = malloc(sizeof(DOM_SID) * *count);
+	if (! *sids) {
+		return NT_STATUS_NO_MEMORY;
+	}
+	for (i=0, p=data.dptr; p<data.dptr+data.dsize; i++) {
+		if (!string_to_sid(&(*sids)[i], p)) {
+			free(data.dptr);
+			return NT_STATUS_INTERNAL_DB_CORRUPTION;
+		}
+		p += strlen(p) + 1;
+	}
+	
+	free(data.dptr);
+
+	return NT_STATUS_OK;
+}
+
+/* 
+   set what accounts have a given right - this is an internal interface
+*/
+static NTSTATUS privilege_set_accounts_with_right(const char *right, 
+						  uint32 count, 
+						  DOM_SID *sids)
+{
+	TDB_DATA data;
+	char *p;
+	int i;
+
+	if (!tdb) {
+		return NT_STATUS_INTERNAL_ERROR;
+	}
+
+	/* allocate the maximum size that we might use */
+	data.dptr = malloc(count * ((MAXSUBAUTHS*11) + 30));
+	if (!data.dptr) {
+		return NT_STATUS_NO_MEMORY;
+	}
+
+	p = data.dptr;
+
+	for (i=0;i<count;i++) {
+		sid_to_string(p, &sids[i]);
+		p += strlen(p) + 1;
+	}
+
+	data.dsize = PTR_DIFF(p, data.dptr);
+
+	if (tdb_store_by_string(tdb, right, data, TDB_REPLACE) != 0) {
+		free(data.dptr);
+		return NT_STATUS_INTERNAL_ERROR;
+	}
+
+	free(data.dptr);
+	return NT_STATUS_OK;
+}
+
+
+/* 
+   add a SID to the list of SIDs for a right
+*/
+NTSTATUS privilege_add_account_right(const char *right, 
+				     DOM_SID *sid)
+{
+	NTSTATUS status;
+	DOM_SID *current_sids;
+	uint32 current_count;
+	int i;
+
+	status = privilege_lock_right(right);
+	if (!NT_STATUS_IS_OK(status)) {
+		return status;
+	}
+
+	status = privilege_enum_account_with_right(right, &current_count, &current_sids);
+	if (!NT_STATUS_IS_OK(status)) {
+		privilege_unlock_right(right);
+		return status;
+	}	
+
+	/* maybe that SID is already listed? this is not an error */
+	for (i=0;i<current_count;i++) {
+		if (sid_equal(&current_sids[i], sid)) {
+			privilege_unlock_right(right);
+			free(current_sids);
+			return NT_STATUS_OK;
+		}
+	}
+
+	/* add it in */
+	current_sids = Realloc(current_sids, sizeof(current_sids[0]) * (current_count+1));
+	if (!current_sids) {
+		privilege_unlock_right(right);
+		return NT_STATUS_NO_MEMORY;
+	}
+
+	sid_copy(&current_sids[current_count], sid);
+	current_count++;
+	
+	status = privilege_set_accounts_with_right(right, current_count, current_sids);
+
+	free(current_sids);
+	privilege_unlock_right(right);
+
+	return status;
+}
+
+
+/* 
+   remove a SID from the list of SIDs for a right
+*/
+NTSTATUS privilege_remove_account_right(const char *right, 
+					DOM_SID *sid)
+{
+	NTSTATUS status;
+	DOM_SID *current_sids;
+	uint32 current_count;
+	int i;
+
+	status = privilege_lock_right(right);
+	if (!NT_STATUS_IS_OK(status)) {
+		return status;
+	}
+
+	status = privilege_enum_account_with_right(right, &current_count, &current_sids);
+	if (!NT_STATUS_IS_OK(status)) {
+		privilege_unlock_right(right);
+		return status;
+	}	
+
+	for (i=0;i<current_count;i++) {
+		if (sid_equal(&current_sids[i], sid)) {
+			/* found it - so remove it */
+			if (current_count-i > 1) {
+				memmove(&current_sids[i], &current_sids[i+1],
+					sizeof(current_sids[0]) * ((current_count-i)-1));
+			}
+			current_count--;
+			status = privilege_set_accounts_with_right(right, 
+								   current_count, 
+								   current_sids);
+			free(current_sids);
+			privilege_unlock_right(right);
+			return status;
+		}
+	}
+
+	/* removing a right that you don't have is not an error */
+	
+	safe_free(current_sids);
+	privilege_unlock_right(right);
+	return NT_STATUS_OK;
+}
+
+
+/*
+  an internal function for checking if a SID has a right
+*/
+static BOOL privilege_sid_has_right(DOM_SID *sid, const char *right)
+{
+	NTSTATUS status;
+	uint32 count;
+	DOM_SID *sids;
+	int i;
+
+	status = privilege_enum_account_with_right(right, &count, &sids);
+	if (!NT_STATUS_IS_OK(status)) {
+		return False;
+	}
+	for (i=0;i<count;i++) {
+		if (sid_equal(sid, &sids[i])) {
+			free(sids);
+			return True;
+		}
+	}	
+
+	safe_free(sids);
+	return False;
+}
+
+/* 
+   list the rights for an account. This involves traversing the database
+*/
+NTSTATUS privilege_enum_account_rights(DOM_SID *sid,
+				       uint32 *count,
+				       char ***rights)
+{
+	TDB_DATA key, nextkey;
+	char *right;
+
+	if (!tdb) {
+		return NT_STATUS_INTERNAL_ERROR;
+	}
+
+	*rights = NULL;
+	*count = 0;
+
+	for (key = tdb_firstkey(tdb); key.dptr; key = nextkey) {
+		nextkey = tdb_nextkey(tdb, key);
+
+		right = key.dptr;
+		
+		if (privilege_sid_has_right(sid, right)) {
+			(*rights) = (char **)Realloc(*rights,sizeof(char *) * ((*count)+1));
+			if (! *rights) {
+				safe_free(nextkey.dptr);
+				free(key.dptr);
+				return NT_STATUS_NO_MEMORY;
+			}
+
+			(*rights)[*count] = strdup(right);
+			(*count)++;
+		}
+
+		free(key.dptr);
+	}
+
+	return NT_STATUS_OK;
+}