Kernel Pointer Leak in iSCSI Transport Registration

CVE-2021-27363 · MEDIUM Severity

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:L

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.

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