REMAP cmd of SVM driver can be used to remap read only memory as read-write, then cause read only memory/file modified.

REMAP cmd of SVM driver can be used to remap read only memory as read-write, then cause read only memory/file modified.

Affected: openEuler:20.03-LTS-SP3: kernel

The Linux Kernel, the operating system core itself. Security Fix(es): The Linux kernel does not correctly mitigate SMT attacks, as discovered through a strange pattern in the kernel API using STIBP as a mitigation[1 <https://docs.kernel.org/userspace-api/spec_ctrl.html>], leaving the process exposed for a short period of time after a syscall. The kernel also does not issue an IBPB immediately during the syscall. The ib_prctl_set [2 <https://elixir.bootlin.com/linux/v5.15.56/source/arch/x86/kernel/cpu/bugs.c#L1467>]function updates the Thread Information Flags (TIFs) for the task and updates the SPEC_CTRL MSR on the function __speculation_ctrl_update [3 <https://elixir.bootlin.com/linux/v5.15.56/source/arch/x86/kernel/process.c#L557>], but the IBPB is only issued on the next schedule, when the TIF bits are checked. This leaves the victim vulnerable to values already injected on the BTB, prior to the prctl syscall. The behavior is only corrected after a reschedule of the task happens. Furthermore, the kernel entrance (due to the syscall itself), does not issue an IBPB in the default scenarios (i.e., when the kernel protects itself via retpoline or eIBRS).(CVE-2023-0045) REMAP cmd of SVM driver can be used to remap read only memory as read-write, then cause read only memory/file modified..(CVE-2021-33639)