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res_musiconhold.c: Prevent crash with realtime MoH

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The MoH class internal file vector is potentially being manipulated by
multiple threads at the same time without sufficient locking. Switch to
a reference counted list and operate on copies where necessary.

ASTERISK-28927 #close

Change-Id: I479c5dcf88db670956e8cac177b5826c986b0217
changes/73/14673/4
Sean Bright 5 years ago committed by Friendly Automation
parent 447f6cc37a
commit b7c2205402
1 changed files with 138 additions and 32 deletions
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170
res/res_musiconhold.c
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@ -171,8 +171,8 @@ struct mohclass {
char announcement[256];
char mode[80];
char digit;
/*! A vector of filenames in "files" mode */
struct ast_vector_string files;
/*! An immutable vector of filenames in "files" mode */
struct ast_vector_string *files;
unsigned int flags;
/*! The format from the MOH source, not applicable to "files" mode */
struct ast_format *format;
@ -313,6 +313,7 @@ static void moh_files_release(struct ast_channel *chan, void *data)
static int ast_moh_files_next(struct ast_channel *chan)
{
struct moh_files_state *state = ast_channel_music_state(chan);
struct ast_vector_string *files;
int tries;
size_t file_count;
@ -332,16 +333,21 @@ static int ast_moh_files_next(struct ast_channel *chan)
state->announcement = 0;
}
file_count = AST_VECTOR_SIZE(&state->class->files);
ao2_lock(state->class);
files = ao2_bump(state->class->files);
ao2_unlock(state->class);
file_count = AST_VECTOR_SIZE(files);
if (!file_count) {
ast_log(LOG_WARNING, "No files available for class '%s'\n", state->class->name);
ao2_ref(files, -1);
return -1;
}
if (state->pos == 0 && ast_strlen_zero(state->save_pos_filename)) {
/* First time so lets play the file. */
state->save_pos = -1;
} else if (state->save_pos >= 0 && state->save_pos < file_count && !strcmp(AST_VECTOR_GET(&state->class->files, state->save_pos), state->save_pos_filename)) {
} else if (state->save_pos >= 0 && state->save_pos < file_count && !strcmp(AST_VECTOR_GET(files, state->save_pos), state->save_pos_filename)) {
/* If a specific file has been saved confirm it still exists and that it is still valid */
state->pos = state->save_pos;
state->save_pos = -1;
@ -349,7 +355,7 @@ static int ast_moh_files_next(struct ast_channel *chan)
/* Get a random file and ensure we can open it */
for (tries = 0; tries < 20; tries++) {
state->pos = ast_random() % file_count;
if (ast_fileexists(AST_VECTOR_GET(&state->class->files, state->pos), NULL, NULL) > 0) {
if (ast_fileexists(AST_VECTOR_GET(files, state->pos), NULL, NULL) > 0) {
break;
}
}
@ -364,21 +370,22 @@ static int ast_moh_files_next(struct ast_channel *chan)
}
for (tries = 0; tries < file_count; ++tries) {
if (ast_openstream_full(chan, AST_VECTOR_GET(&state->class->files, state->pos), ast_channel_language(chan), 1)) {
if (ast_openstream_full(chan, AST_VECTOR_GET(files, state->pos), ast_channel_language(chan), 1)) {
break;
}
ast_log(LOG_WARNING, "Unable to open file '%s': %s\n", AST_VECTOR_GET(&state->class->files, state->pos), strerror(errno));
ast_log(LOG_WARNING, "Unable to open file '%s': %s\n", AST_VECTOR_GET(files, state->pos), strerror(errno));
state->pos++;
state->pos %= file_count;
}
if (tries == file_count) {
ao2_ref(files, -1);
return -1;
}
/* Record the pointer to the filename for position resuming later */
ast_copy_string(state->save_pos_filename, AST_VECTOR_GET(&state->class->files, state->pos), sizeof(state->save_pos_filename));
ast_copy_string(state->save_pos_filename, AST_VECTOR_GET(files, state->pos), sizeof(state->save_pos_filename));
ast_debug(1, "%s Opened file %d '%s'\n", ast_channel_name(chan), state->pos, state->save_pos_filename);
@ -395,6 +402,7 @@ static int ast_moh_files_next(struct ast_channel *chan)
}
}
ao2_ref(files, -1);
return 0;
}
@ -504,7 +512,9 @@ static void *moh_files_alloc(struct ast_channel *chan, void *params)
}
}
file_count = AST_VECTOR_SIZE(&class->files);
ao2_lock(class);
file_count = AST_VECTOR_SIZE(class->files);
ao2_unlock(class);
/* Resume MOH from where we left off last time or start from scratch? */
if (state->save_total != file_count || strcmp(state->name, class->name) != 0) {
@ -1074,8 +1084,29 @@ static struct ast_generator mohgen = {
.digit = moh_handle_digit,
};
static void moh_file_vector_destructor(void *obj)
{
struct ast_vector_string *files = obj;
AST_VECTOR_RESET(files, ast_free);
AST_VECTOR_FREE(files);
}
static struct ast_vector_string *moh_file_vector_alloc(int initial_capacity)
{
struct ast_vector_string *files = ao2_alloc_options(
sizeof(struct ast_vector_string),
moh_file_vector_destructor,
AO2_ALLOC_OPT_LOCK_NOLOCK);
if (files) {
AST_VECTOR_INIT(files, initial_capacity);
}
return files;
}
static void moh_parse_options(struct ast_variable *var, struct mohclass *mohclass)
{
struct ast_vector_string *playlist_entries = NULL;
for (; var; var = var->next) {
if (!strcasecmp(var->name, "name")) {
ast_copy_string(mohclass->name, var->value, sizeof(mohclass->name));
@ -1083,7 +1114,16 @@ static void moh_parse_options(struct ast_variable *var, struct mohclass *mohclas
ast_copy_string(mohclass->mode, var->value, sizeof(mohclass->mode));
} else if (!strcasecmp(var->name, "entry")) {
if (ast_begins_with(var->value, "/") || ast_begins_with(var->value, "http://") || ast_begins_with(var->value, "https://")) {
char *dup = ast_strdup(var->value);
char *dup;
if (!playlist_entries) {
playlist_entries = moh_file_vector_alloc(16);
if (!playlist_entries) {
continue;
}
}
dup = ast_strdup(var->value);
if (!dup) {
continue;
}
@ -1096,7 +1136,8 @@ static void moh_parse_options(struct ast_variable *var, struct mohclass *mohclas
dup);
}
}
AST_VECTOR_APPEND(&mohclass->files, dup);
AST_VECTOR_APPEND(playlist_entries, dup);
} else {
ast_log(LOG_ERROR, "Playlist entries must be a URL or absolute path, '%s' provided.\n", var->value);
}
@ -1150,7 +1191,21 @@ static void moh_parse_options(struct ast_variable *var, struct mohclass *mohclas
}
}
AST_VECTOR_COMPACT(&mohclass->files);
if (playlist_entries) {
/* If we aren't in playlist mode, drop any list we may have already built */
if (strcasecmp(mohclass->mode, "playlist")) {
ast_log(LOG_NOTICE, "Ignoring playlist entries because we are in '%s' mode.\n",
mohclass->mode);
ao2_ref(playlist_entries, -1);
return;
}
AST_VECTOR_COMPACT(playlist_entries);
/* We don't need to lock here because we are the thread that
* created this mohclass and we haven't published it yet */
ao2_replace(mohclass->files, playlist_entries);
}
}
static int moh_scan_files(struct mohclass *class) {
@ -1162,6 +1217,7 @@ static int moh_scan_files(struct mohclass *class) {
char *ext;
struct stat statbuf;
int res;
struct ast_vector_string *files;
if (class->dir[0] != '/') {
snprintf(dir_path, sizeof(dir_path), "%s/%s", ast_config_AST_DATA_DIR, class->dir);
@ -1175,7 +1231,11 @@ static int moh_scan_files(struct mohclass *class) {
return -1;
}
AST_VECTOR_RESET(&class->files, ast_free);
files = moh_file_vector_alloc(16); /* 16 seems like a reasonable default */
if (!files) {
closedir(files_DIR);
return -1;
}
while ((files_dirent = readdir(files_DIR))) {
char *filepath_copy;
@ -1204,7 +1264,7 @@ static int moh_scan_files(struct mohclass *class) {
*ext = '\0';
/* if the file is present in multiple formats, ensure we only put it into the list once */
if (AST_VECTOR_GET_CMP(&class->files, &filepath[0], !strcmp)) {
if (AST_VECTOR_GET_CMP(files, &filepath[0], !strcmp)) {
continue;
}
@ -1214,9 +1274,9 @@ static int moh_scan_files(struct mohclass *class) {
}
if (ast_test_flag(class, MOH_SORTALPHA)) {
res = AST_VECTOR_ADD_SORTED(&class->files, filepath_copy, strcasecmp);
res = AST_VECTOR_ADD_SORTED(files, filepath_copy, strcasecmp);
} else {
res = AST_VECTOR_APPEND(&class->files, filepath_copy);
res = AST_VECTOR_APPEND(files, filepath_copy);
}
if (res) {
@ -1227,9 +1287,13 @@ static int moh_scan_files(struct mohclass *class) {
closedir(files_DIR);
AST_VECTOR_COMPACT(&class->files);
AST_VECTOR_COMPACT(files);
return AST_VECTOR_SIZE(&class->files);
ao2_lock(class);
ao2_replace(class->files, files);
ao2_unlock(class);
return AST_VECTOR_SIZE(files);
}
static int init_files_class(struct mohclass *class)
@ -1355,7 +1419,13 @@ static int _moh_register(struct mohclass *moh, int reload, int unref, const char
return -1;
}
} else if (!strcasecmp(moh->mode, "playlist")) {
if (!AST_VECTOR_SIZE(&moh->files)) {
size_t file_count;
ao2_lock(moh);
file_count = AST_VECTOR_SIZE(moh->files);
ao2_unlock(moh);
if (!file_count) {
if (unref) {
moh = mohclass_unref(moh, "unreffing potential new moh class (no playlist entries)");
}
@ -1504,7 +1574,13 @@ static struct mohclass *_moh_class_malloc(const char *file, int line, const char
class->format = ao2_bump(ast_format_slin);
class->srcfd = -1;
class->kill_delay = 100000;
AST_VECTOR_INIT(&class->files, 0);
/* We create an empty one by default */
class->files = moh_file_vector_alloc(0);
if (!class->files) {
ao2_ref(class, -1);
return NULL;
}
}
return class;
@ -1647,6 +1723,14 @@ static int local_ast_moh_start(struct ast_channel *chan, const char *mclass, con
mohclass->start -= respawn_time;
if (!strcasecmp(mohclass->mode, "files")) {
/*
* XXX moh_scan_files returns -1 if it is unable to open the
* configured directory or there is a memory allocation
* failure. Otherwise it returns the number of files for this music
* class. This check is only checking if the number of files is zero
* and it ignores the -1 case. To avoid a behavior change we keep this
* as-is, but we should address what the 'correct' behavior should be.
*/
if (!moh_scan_files(mohclass)) {
mohclass = mohclass_unref(mohclass, "unreffing potential mohclass (moh_scan_files failed)");
return -1;
@ -1660,7 +1744,13 @@ static int local_ast_moh_start(struct ast_channel *chan, const char *mclass, con
ast_set_flag(mohclass, MOH_RANDOMIZE);
}
} else if (!strcasecmp(mohclass->mode, "playlist")) {
if (!AST_VECTOR_SIZE(&mohclass->files)) {
size_t file_count;
ao2_lock(mohclass);
file_count = AST_VECTOR_SIZE(mohclass->files);
ao2_unlock(mohclass);
if (!file_count) {
mohclass = mohclass_unref(mohclass, "unreffing potential mohclass (no playlist entries)");
return -1;
}
@ -1723,6 +1813,13 @@ static int local_ast_moh_start(struct ast_channel *chan, const char *mclass, con
/* If we are using a cached realtime class with files, re-scan the files */
if (!var && ast_test_flag(global_flags, MOH_CACHERTCLASSES) && mohclass->realtime && !strcasecmp(mohclass->mode, "files")) {
/*
* XXX moh_scan_files returns -1 if it is unable to open the configured directory
* or there is a memory allocation failure. Otherwise it returns the number of
* files for this music class. This check is only checking if the number of files
* is zero and it ignores the -1 case. To avoid a behavior change we keep this
* as-is, but we should address what the 'correct' behavior should be.
*/
if (!moh_scan_files(mohclass)) {
mohclass = mohclass_unref(mohclass, "unreffing potential mohclass (moh_scan_files failed)");
return -1;
@ -1730,7 +1827,13 @@ static int local_ast_moh_start(struct ast_channel *chan, const char *mclass, con
}
if (!state || !state->class || strcmp(mohclass->name, state->class->name)) {
if (AST_VECTOR_SIZE(&mohclass->files)) {
size_t file_count;
ao2_lock(mohclass);
file_count = AST_VECTOR_SIZE(mohclass->files);
ao2_unlock(mohclass);
if (file_count) {
res = ast_activate_generator(chan, &moh_file_stream, mohclass);
} else {
res = ast_activate_generator(chan, &mohgen, mohclass);
@ -1775,6 +1878,7 @@ static void moh_class_destructor(void *obj)
while ((member = AST_LIST_REMOVE_HEAD(&class->members, list))) {
ast_free(member);
}
ao2_cleanup(class->files);
ao2_unlock(class);
/* Kill the thread first, so it cannot restart the child process while the
@ -1809,9 +1913,6 @@ static void moh_class_destructor(void *obj)
class->srcfd = -1;
}
AST_VECTOR_RESET(&class->files, ast_free);
AST_VECTOR_FREE(&class->files);
if (class->timer) {
ast_timer_close(class->timer);
class->timer = NULL;
@ -1993,16 +2094,21 @@ static char *handle_cli_moh_show_files(struct ast_cli_entry *e, int cmd, struct
i = ao2_iterator_init(mohclasses, 0);
for (; (class = ao2_t_iterator_next(&i, "Show files iterator")); mohclass_unref(class, "Unref iterator in moh show files")) {
int x;
struct ast_vector_string *files;
if (!AST_VECTOR_SIZE(&class->files)) {
continue;
}
ao2_lock(class);
files = ao2_bump(class->files);
ao2_unlock(class);
ast_cli(a->fd, "Class: %s\n", class->name);
for (x = 0; x < AST_VECTOR_SIZE(&class->files); x++) {
ast_cli(a->fd, "\tFile: %s\n", AST_VECTOR_GET(&class->files, x));
if (AST_VECTOR_SIZE(files)) {
int x;
ast_cli(a->fd, "Class: %s\n", class->name);
for (x = 0; x < AST_VECTOR_SIZE(files); x++) {
ast_cli(a->fd, "\tFile: %s\n", AST_VECTOR_GET(files, x));
}
}
ao2_ref(files, -1);
}
ao2_iterator_destroy(&i);

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