CVE-2026-23243 RDMA/umad: Reject negative data_len in ib_umad_write

In the Linux kernel, the following vulnerability has been resolved: RDMA/umad: Reject negative datalen in ibumadwrite ibumadwrite computes datalen from user-controlled count and the MAD header sizes. With a mismatched user MAD header size and RMPP header length, datalen can become negative and...