CVE-2024-56720 bpf, sockmap: Several fixes to bpf_msg_pop_data

In the Linux kernel, the following vulnerability has been resolved: bpf, sockmap: Several fixes to bpfmsgpopdata Several fixes to bpfmsgpopdata, 1. In skmsgshiftleft, we should putpage 2. if len == 0, return early is better 3. pop the entire skmsg last == msg-sg.size should be supported 4. Fix fo...