[Asterisk-code-review] res_musiconhold.c: Prevent crash with realtime MoH (asterisk[master])
Friendly Automation
asteriskteam at digium.com
Tue Aug 11 16:58:30 CDT 2020
Friendly Automation has submitted this change. ( https://gerrit.asterisk.org/c/asterisk/+/14673 )
Change subject: res_musiconhold.c: Prevent crash with realtime MoH
......................................................................
res_musiconhold.c: Prevent crash with realtime MoH
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
---
M res/res_musiconhold.c
1 file changed, 138 insertions(+), 32 deletions(-)
Approvals:
Joshua Colp: Looks good to me, but someone else must approve
Kevin Harwell: Looks good to me, approved
Friendly Automation: Approved for Submit
diff --git a/res/res_musiconhold.c b/res/res_musiconhold.c
index 01a14b9..dd8dba5 100644
--- a/res/res_musiconhold.c
+++ b/res/res_musiconhold.c
@@ -171,8 +171,8 @@
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 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 @@
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 @@
/* 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 @@
}
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 @@
}
}
+ ao2_ref(files, -1);
return 0;
}
@@ -504,7 +512,9 @@
}
}
- 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 @@
.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 @@
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 @@
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 @@
}
}
- 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 @@
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 @@
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 @@
*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 @@
}
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 @@
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 @@
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 @@
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 @@
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 @@
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 @@
/* 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 @@
}
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 @@
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 @@
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 @@
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);
+
+ 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));
+ }
}
- 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));
- }
+ ao2_ref(files, -1);
}
ao2_iterator_destroy(&i);
--
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Gerrit-Project: asterisk
Gerrit-Branch: master
Gerrit-Change-Id: I479c5dcf88db670956e8cac177b5826c986b0217
Gerrit-Change-Number: 14673
Gerrit-PatchSet: 4
Gerrit-Owner: Sean Bright <sean.bright at gmail.com>
Gerrit-Reviewer: Friendly Automation
Gerrit-Reviewer: Joshua Colp <jcolp at sangoma.com>
Gerrit-Reviewer: Kevin Harwell <kharwell at digium.com>
Gerrit-MessageType: merged
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