app_voicemail: Fix crash when VM_INFO reads an unset email address.

The email member of struct ast_vm_user is a pointer rather than a fixed
array, and populate_defaults() leaves it NULL when a mailbox has no
email address configured. Every other attribute VM_INFO reads is a fixed
array, so only the email attribute is affected.

VM_INFO passed vmu->email straight to ast_copy_string(), which
dereferences its source unconditionally. Reading the email attribute of
a mailbox that has no email address therefore crashed Asterisk from the
dialplan.

Guard the copy with S_OR() so an unset email address yields an empty
string, matching how the language attribute already handles its
fallback. The make_email_file() call sites were already guarded and are
left alone.

Add a regression test for the unset case, and restore the voicemail
configuration when the VM_INFO test finishes. That test was the only one
in app_voicemail that did not do so, which left its test mailbox in the
users list and made the test fail if it ran a second time.

Fixes: #2063

diff --git a/apps/app_voicemail.c b/apps/app_voicemail.c
index 9a3275d0a47ccf5d59d9a00d71546070e6f074d1..258d294471cde281d77a051201d7e2df3494be6f 100644 (file)
--- a/apps/app_voicemail.c
+++ b/apps/app_voicemail.c
@@ -13658,7 +13658,7 @@ static int acf_vm_info(struct ast_channel *chan, const char *cmd, char *args, ch
                } else if (!strncasecmp(arg.attribute, "fullname", 8)) {
                        ast_copy_string(buf, vmu->fullname, len);
                } else if (!strncasecmp(arg.attribute, "email", 5)) {
-                       ast_copy_string(buf, vmu->email, len);
+                       ast_copy_string(buf, S_OR(vmu->email, ""), len);
                } else if (!strncasecmp(arg.attribute, "pager", 5)) {
                        ast_copy_string(buf, vmu->pager, len);
                } else if (!strncasecmp(arg.attribute, "language", 8)) {
@@ -16132,8 +16132,23 @@ AST_TEST_DEFINE(test_voicemail_vm_info)
                }
        }
 
+       ast_free(vmu->email);
+       vmu->email = NULL;
+
+       ast_copy_string(vminfo_args, "00000000@test,email", sizeof(vminfo_args));
+       test_ret = acf_vm_info(chan, vminfo_cmd, vminfo_args, vminfo_buf, sizeof(vminfo_buf));
+       if (!ast_strlen_zero(vminfo_buf)) {
+               ast_test_status_update(test, "VM_INFO response for a mailbox without an email address was: '%s', but expected: ''\n", vminfo_buf);
+               res = AST_TEST_FAIL;
+       }
+       if (test_ret != 0) {
+               ast_test_status_update(test, "VM_INFO return code for a mailbox without an email address was: '%i', but expected '0'\n", test_ret);
+               res = AST_TEST_FAIL;
+       }
+
        chan = ast_channel_unref(chan);
        free_user(vmu);
+       force_reload_config(); /* Restore original config */
        return res;
 }
 #endif /* defined(TEST_FRAMEWORK) */