net: qrtr: restrict socket creation to the initial network namespace

Overview

In the Linux kernel, the following vulnerability has been resolved:

net: qrtr: restrict socket creation to the initial network namespace

QRTR keeps its entire port and node state in module-global variables that are not partitioned per network namespace: qrtr_local_nid is a single global node id (always 1) and qrtr_ports is a single global xarray. qrtr_port_lookup() and qrtr_local_enqueue() operate on that global state with no network-namespace check, and qrtr_create() places no restriction on the namespace a socket is created in.

As a result an unprivileged process that creates an AF_QIPCRTR socket in a separate network namespace, e.g. via unshare(CLONE_NEWUSER | CLONE_NEWNET), can send QRTR datagrams - including control-plane messages such as QRTR_TYPE_NEW_SERVER - to QRTR sockets owned by another namespace, and vice versa. The receiving socket sees such a message as coming from node id 1, indistinguishable from a legitimate local client, breaking the isolation that network namespaces are expected to provide.

QRTR is a transport to global hardware endpoints (the modem and other remote processors) and has no per-namespace semantics; its in-kernel name service already creates its socket in init_net only. Confine the socket family to the initial network namespace, as other non-namespace-aware socket families do (see llc_ui_create() and the ieee802154 socket code).

Affected

• Linux >= bdabad3e363d825ddf9679dd431cca0b2c30f881 < 7814f6a3415cad38aa8d6dfc573df778260d66aa
• Linux >= bdabad3e363d825ddf9679dd431cca0b2c30f881 < 2d22b94a154ccb9755dddfff802fe3e2b1adbab5
• Linux >= bdabad3e363d825ddf9679dd431cca0b2c30f881 < 8d351fe0654a20c9f95a61b05d24ebe6d4be3fbb
• Linux >= bdabad3e363d825ddf9679dd431cca0b2c30f881 < 4b95e1f0d6e6342c427cb341ee18a894b146b789
• Linux >= bdabad3e363d825ddf9679dd431cca0b2c30f881 < f488116df769bdaf89c93371350e49e12133e70f
• Linux >= bdabad3e363d825ddf9679dd431cca0b2c30f881 < 8150c48fb978e01689f94ed80148f8a7499ae571
• Linux >= bdabad3e363d825ddf9679dd431cca0b2c30f881 < 659b9b4f194bb56b9903cc95e786ef1d438baa7d
• Linux >= bdabad3e363d825ddf9679dd431cca0b2c30f881 < 3b536db8fb32da9e9c62f2bb45e2e319331f0426
• Linux 4.7

Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.