propagate nvmet_tcp_build_pdu_iovec() errors to its callers

Summary

In the Linux kernel, the following vulnerability has been resolved: nvmet-tcp: propagate nvmet_tcp_build_pdu_iovec() errors to its callers Currently, when nvmet_tcp_build_pdu_iovec() detects an out-of-bounds PDU length or offset, it triggers nvmet_tcp_fatal_error(cmd->queue) and returns early. However, because the function returns void, the callers are entirely unaware that a fatal error has occurred and that the cmd->recv_msg.msg_iter was left uninitialized. Callers such as nvmet_tcp_handle_h2c_data_pdu() proceed to blindly overwrite the queue state with queue->rcv_state = NVMET_TCP_RECV_DATA Consequently, the socket receiving loop may attempt to read incoming network data into the uninitialized iterator. Fix this by shifting the error handling responsibility to the callers. A flaw was found in the `nvmet-tcp` component of the Linux kernel. The `nvmet_tcp_build_pdu_iovec()` function fails to propagate errors when detecting out-of-bounds PDU lengths or offsets. This can lead to uninitialized memory being used by subsequent operations, such as reading incoming network data into an uninitialized iterator. A remote attacker could potentially exploit this memory corruption to cause a denial of service or achieve arbitrary code execution. Red Hat severity: Important — CVSS 7 (CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H). Weakness: CWE-390. No fixing RHSA erratum has published yet; monitor the Red Hat CVE page and patch when it ships.