MGASA-2021-0151

This kernel update is based on upstream 5.10.25 and fixes at least the following security issues:

Unprivileged BPF programs running on affected systems can bypass the protection and execute speculatively out-of-bounds loads from any location within the kernel memory. This can be abused to extract contents of kernel memory via side-channel (CVE-2020-27170).

Unprivileged BPF programs running on affected 64-bit systems can exploit this to execute speculatively out-of-bounds loads from 4GB window within the kernel memory. This can be abused to extract contents of kernel memory via side-channel (CVE-2020-27171).

An issue was discovered in the Linux kernel through 5.11.3. A kernel pointer leak can be used to determine the address of the iscsi_transport structure. When an iSCSI transport is registered with the iSCSI subsystem, the transport's handle is available to unprivileged users via the sysfs file system, at /sys/class/iscsi_transport/$TRANSPORT_NAME/handle. When read, the show_transport_handle function (in drivers/scsi/scsi_transport_iscsi.c) is called, which leaks the handle. This handle is actually the pointer to an iscsi_transport struct in the kernel module's global variables (CVE-2021-27363).

An issue was discovered in the Linux kernel through 5.11.3. drivers/scsi/ scsi_transport_iscsi.c is adversely affected by the ability of an unprivileged user to craft Netlink messages (CVE-2021-27364).

An issue was discovered in the Linux kernel through 5.11.3. Certain iSCSI data structures do not have appropriate length constraints or checks, and can exceed the PAGE_SIZE value. An unprivileged user can send a Netlink message that is associated with iSCSI, and has a length up to the maximum length of a Netlink message (CVE-2021-27365).

An issue was discovered in the Linux kernel through 5.11.6. fastrpc_internal_invoke in drivers/misc/fastrpc.c does not prevent user applications from sending kernel RPC messages (CVE-2021-28375).

It also adds the following fixes:

• arm(64): enable W1_MASTER_GPIO (mga#28596)
• wireguard-tools have been updated to v1.0.20210315

For other upstream fixes, see the referenced changelogs.