Rfc4515

How LDAP injection happens in C with OpenLDAP and how to fix it

A high-severity LDAP injection vulnerability was discovered in the OpenSIPS H350 module, where the `ldap_rfc4515_escape()` function failed to escape the NUL byte (`\0`) — one of the special characters defined in RFC 4515. This gap meant that crafted SIP URI values could bypass the escaping logic and manipulate LDAP filter queries. The fix adds explicit NUL byte escaping and replaces potentially unsafe `strncpy` calls with `memcpy` to ensure correct buffer handling.