Fix a potential crash situation when using IMAP voicemail

If calling into VoiceMailMain when using IMAP storage, it was
possible to crash Asterisk by hanging up the phone when prompted
for a voicemail mailbox. This patch fixes the issue.

While it may appear that this patch is superficial, it allows code
execution to continue to the failure case just below the IMAP_STORAGE
code block where this patch has been applied

(closes issue #14473)
Reported by: dwpaul
Patches:
      voicemail_imap_crash_no_mailbox.patch uploaded by dwpaul (license 689)

git-svn-id: https://origsvn.digium.com/svn/asterisk/branches/1.4@175590 65c4cc65-6c06-0410-ace0-fbb531ad65f3

diff --git a/apps/app_voicemail.c b/apps/app_voicemail.c
index 6a4677aa9699f8d25f459c407257b9e13e52dc48..3566e71f40fa39c1c59edee4ede24117c9dfc6b9 100644 (file)
--- a/apps/app_voicemail.c
+++ b/apps/app_voicemail.c
@@ -7326,7 +7326,8 @@ static int vm_execmain(struct ast_channel *chan, void *data)
 #ifdef IMAP_STORAGE
        vms.interactive = 1;
        vms.updated = 1;
-       ast_copy_string(vms.context, vmu->context, sizeof(vms.context));
+       if (vmu)
+               ast_copy_string(vms.context, vmu->context, sizeof(vms.context));
        vmstate_insert(&vms);
        init_vm_state(&vms);
 #endif