4e72ad1b4f
The AST_CONFIG dialplan function defined in func_config.c allocates its config file list entries using ast_malloc. List entry allocations destined for use with Asterisk's linked list API must be ast_calloc()d or otherwise initialized so that list pointers are set to NULL. These uses of ast_malloc have been replaced by ast_calloc to prevent dereferencing of uninitialized pointer values when traversing the list. (closes issue ASTERISK-22483) Reported by: Brian Scott ........ Merged revisions 400694 from http://svn.asterisk.org/svn/asterisk/branches/1.8 ........ Merged revisions 400697 from http://svn.asterisk.org/svn/asterisk/branches/11 ........ Merged revisions 400701 from http://svn.asterisk.org/svn/asterisk/branches/12 git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@400704 65c4cc65-6c06-0410-ace0-fbb531ad65f3
208 lines
5 KiB
C
208 lines
5 KiB
C
/*
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* Asterisk -- An open source telephony toolkit.
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*
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* Copyright (C) 2008, Digium, Inc.
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*
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* Russell Bryant <russell@digium.com>
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* Tilghman Lesher <func_config__200803@the-tilghman.com>
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*
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* See http://www.asterisk.org for more information about
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* the Asterisk project. Please do not directly contact
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* any of the maintainers of this project for assistance;
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* the project provides a web site, mailing lists and IRC
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* channels for your use.
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*
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* This program is free software, distributed under the terms of
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* the GNU General Public License Version 2. See the LICENSE file
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* at the top of the source tree.
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*/
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/*! \file
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*
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* \brief A function to retrieve variables from an Asterisk configuration file
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*
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* \author Russell Bryant <russell@digium.com>
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* \author Tilghman Lesher <func_config__200803@the-tilghman.com>
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*
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* \ingroup functions
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*/
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/*** MODULEINFO
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<support_level>core</support_level>
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***/
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#include "asterisk.h"
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ASTERISK_FILE_VERSION(__FILE__, "$Revision$")
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#include "asterisk/module.h"
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#include "asterisk/channel.h"
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#include "asterisk/pbx.h"
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#include "asterisk/app.h"
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/*** DOCUMENTATION
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<function name="AST_CONFIG" language="en_US">
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<synopsis>
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Retrieve a variable from a configuration file.
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</synopsis>
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<syntax>
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<parameter name="config_file" required="true" />
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<parameter name="category" required="true" />
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<parameter name="variable_name" required="true" />
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</syntax>
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<description>
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<para>This function reads a variable from an Asterisk configuration file.</para>
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</description>
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</function>
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***/
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struct config_item {
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AST_RWLIST_ENTRY(config_item) entry;
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struct ast_config *cfg;
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char filename[0];
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};
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static AST_RWLIST_HEAD_STATIC(configs, config_item);
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static int config_function_read(struct ast_channel *chan, const char *cmd, char *data,
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char *buf, size_t len)
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{
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struct ast_config *cfg;
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struct ast_flags cfg_flags = { CONFIG_FLAG_FILEUNCHANGED };
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const char *val;
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char *parse;
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struct config_item *cur;
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AST_DECLARE_APP_ARGS(args,
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AST_APP_ARG(filename);
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AST_APP_ARG(category);
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AST_APP_ARG(variable);
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AST_APP_ARG(index);
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);
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if (ast_strlen_zero(data)) {
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ast_log(LOG_ERROR, "AST_CONFIG() requires an argument\n");
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return -1;
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}
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parse = ast_strdupa(data);
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AST_STANDARD_APP_ARGS(args, parse);
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if (ast_strlen_zero(args.filename)) {
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ast_log(LOG_ERROR, "AST_CONFIG() requires a filename\n");
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return -1;
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}
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if (ast_strlen_zero(args.category)) {
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ast_log(LOG_ERROR, "AST_CONFIG() requires a category\n");
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return -1;
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}
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if (ast_strlen_zero(args.variable)) {
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ast_log(LOG_ERROR, "AST_CONFIG() requires a variable\n");
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return -1;
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}
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if (!(cfg = ast_config_load(args.filename, cfg_flags)) || cfg == CONFIG_STATUS_FILEINVALID) {
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return -1;
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}
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if (cfg == CONFIG_STATUS_FILEUNCHANGED) {
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/* Retrieve cfg from list */
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AST_RWLIST_RDLOCK(&configs);
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AST_RWLIST_TRAVERSE(&configs, cur, entry) {
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if (!strcmp(cur->filename, args.filename)) {
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break;
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}
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}
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if (!cur) {
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/* At worst, we might leak an entry while upgrading locks */
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AST_RWLIST_UNLOCK(&configs);
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AST_RWLIST_WRLOCK(&configs);
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if (!(cur = ast_calloc(1, sizeof(*cur) + strlen(args.filename) + 1))) {
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AST_RWLIST_UNLOCK(&configs);
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return -1;
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}
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strcpy(cur->filename, args.filename);
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ast_clear_flag(&cfg_flags, CONFIG_FLAG_FILEUNCHANGED);
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if (!(cfg = ast_config_load(args.filename, cfg_flags)) || cfg == CONFIG_STATUS_FILEINVALID) {
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ast_free(cur);
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AST_RWLIST_UNLOCK(&configs);
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return -1;
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}
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cur->cfg = cfg;
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AST_RWLIST_INSERT_TAIL(&configs, cur, entry);
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}
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cfg = cur->cfg;
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} else {
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/* Replace cfg in list */
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AST_RWLIST_WRLOCK(&configs);
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AST_RWLIST_TRAVERSE(&configs, cur, entry) {
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if (!strcmp(cur->filename, args.filename)) {
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break;
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}
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}
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if (!cur) {
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if (!(cur = ast_calloc(1, sizeof(*cur) + strlen(args.filename) + 1))) {
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AST_RWLIST_UNLOCK(&configs);
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return -1;
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}
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strcpy(cur->filename, args.filename);
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cur->cfg = cfg;
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AST_RWLIST_INSERT_TAIL(&configs, cur, entry);
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} else {
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ast_config_destroy(cur->cfg);
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cur->cfg = cfg;
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}
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}
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if (!(val = ast_variable_retrieve(cfg, args.category, args.variable))) {
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ast_log(LOG_ERROR, "'%s' not found in [%s] of '%s'\n", args.variable,
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args.category, args.filename);
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AST_RWLIST_UNLOCK(&configs);
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return -1;
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}
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ast_copy_string(buf, val, len);
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/* Unlock down here, so there's no chance the struct goes away while we're using it. */
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AST_RWLIST_UNLOCK(&configs);
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return 0;
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}
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static struct ast_custom_function config_function = {
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.name = "AST_CONFIG",
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.read = config_function_read,
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};
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static int unload_module(void)
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{
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struct config_item *current;
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int res = ast_custom_function_unregister(&config_function);
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AST_RWLIST_WRLOCK(&configs);
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while ((current = AST_RWLIST_REMOVE_HEAD(&configs, entry))) {
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ast_config_destroy(current->cfg);
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ast_free(current);
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}
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AST_RWLIST_UNLOCK(&configs);
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return res;
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}
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static int load_module(void)
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{
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return ast_custom_function_register(&config_function);
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}
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AST_MODULE_INFO_STANDARD(ASTERISK_GPL_KEY, "Asterisk configuration file variable access");
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