multi: CURLINFO_LASTSOCKET doesn't work after remove_handle
When curl_multi_remove_handle() is called and an easy handle is returned
to the connection cache held in the multi handle, then we cannot allow
CURLINFO_LASTSOCKET to extract it since that will more or less encourage
that the user uses the socket while it can get used by libcurl again.
Without this fix, we'd get a segfault in Curl_getconnectinfo() trying to
dereference the NULL pointer in 'data->state.connc'.
Bug: http://curl.haxx.se/bug/view.cgi?id=3023840
diff --git a/lib/multi.c b/lib/multi.c
index ea284b3..9273f8d 100644
--- a/lib/multi.c
+++ b/lib/multi.c
@@ -656,6 +656,10 @@
to that since we're not part of that handle anymore */
easy->easy_handle->state.connc = NULL;
+ /* Since we return the connection back to the communal connection pool
+ we mark the last connection as inaccessible */
+ easy->easy_handle->state.lastconnect = -1;
+
/* Modify the connectindex since this handle can't point to the
connection cache anymore.
