Fix a potential segfault if chan (or chan->music_state) is NULL.

Closes issue #12210, credit to edantie for pointing this out.

git-svn-id: https://origsvn.digium.com/svn/asterisk/branches/1.4@108682 65c4cc65-6c06-0410-ace0-fbb531ad65f3

diff --git a/res/res_musiconhold.c b/res/res_musiconhold.c
index b1955825ad43449af95c2a23b24cae4d634e29ab..87b3278974bfdf6a8f788ea4ccdee25452ea6e0f 100644 (file)
--- a/res/res_musiconhold.c
+++ b/res/res_musiconhold.c
@@ -200,23 +200,26 @@ static void ast_moh_free_class(struct mohclass **mohclass)
 
 static void moh_files_release(struct ast_channel *chan, void *data)
 {
-       struct moh_files_state *state = chan->music_state;
+       struct moh_files_state *state;
 
-       if (chan && state) {
-               if (chan->stream) {
-                        ast_closestream(chan->stream);
-                        chan->stream = NULL;
-                }
-               if (option_verbose > 2)
-                       ast_verbose(VERBOSE_PREFIX_3 "Stopped music on hold on %s\n", chan->name);
+       if (chan) {
+               if ((state = chan->music_state)) {
+                       if (chan->stream) {
+                               ast_closestream(chan->stream);
+                               chan->stream = NULL;
+                       }
+                       if (option_verbose > 2)
+                               ast_verbose(VERBOSE_PREFIX_3 "Stopped music on hold on %s\n", chan->name);
+       
+                       if (state->origwfmt && ast_set_write_format(chan, state->origwfmt)) {
+                               ast_log(LOG_WARNING, "Unable to restore channel '%s' to format '%d'\n", chan->name, state->origwfmt);
+                       }
+                       state->save_pos = state->pos;
 
-               if (state->origwfmt && ast_set_write_format(chan, state->origwfmt)) {
-                       ast_log(LOG_WARNING, "Unable to restore channel '%s' to format '%d'\n", chan->name, state->origwfmt);
+                       if (ast_atomic_dec_and_test(&state->class->inuse) && state->class->delete)
+                               ast_moh_destroy_one(state->class);
                }
-               state->save_pos = state->pos;
        }
-       if (ast_atomic_dec_and_test(&state->class->inuse) && state->class->delete)
-               ast_moh_destroy_one(state->class);
 }