Commit afe18b25 authored by Russell King (Oracle)'s avatar Russell King (Oracle) Committed by Zheng Zengkai
Browse files

ARM: include unprivileged BPF status in Spectre V2 reporting 

stable inclusion
from stable-v5.10.105
commit 302754d023a06171113e8fb20c7b2a18ebf9088f
category: bugfix
bugzilla: 186460 https://gitee.com/src-openeuler/kernel/issues/I53MHA
CVE: CVE-2022-23960

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=302754d023a0



--------------------------------

commit 25875aa7 upstream.

The mitigations for Spectre-BHB are only applied when an exception
is taken, but when unprivileged BPF is enabled, userspace can
load BPF programs that can be used to exploit the problem.

When unprivileged BPF is enabled, report the vulnerable status via
the spectre_v2 sysfs file.

Signed-off-by: default avatarRussell King (Oracle) <rmk+kernel@armlinux.org.uk>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: default avatarChen Jiahao <chenjiahao16@huawei.com>
Reviewed-by: default avatarLiao Chang <liaochang1@huawei.com>
Signed-off-by: default avatarZheng Zengkai <zhengzengkai@huawei.com>
parent a371a70b

arch/arm/kernel/spectre.c

+13 −0
Original line number Diff line number Diff line 
// SPDX-License-Identifier: GPL-2.0-only

#include <linux/bpf.h>

#include <linux/cpu.h>

#include <linux/device.h>



#include <asm/spectre.h>



static bool _unprivileged_ebpf_enabled(void)

{

#ifdef CONFIG_BPF_SYSCALL

	return !sysctl_unprivileged_bpf_disabled;

#else

	return false;

#endif

}



ssize_t cpu_show_spectre_v1(struct device *dev, struct device_attribute *attr,

			    char *buf)

{
@@ -31,6 +41,9 @@ ssize_t cpu_show_spectre_v2(struct device *dev, struct device_attribute *attr, 
	if (spectre_v2_state != SPECTRE_MITIGATED)

		return sprintf(buf, "%s\n", "Vulnerable");



	if (_unprivileged_ebpf_enabled())

		return sprintf(buf, "Vulnerable: Unprivileged eBPF enabled\n");



	switch (spectre_v2_methods) {

	case SPECTRE_V2_METHOD_BPIALL:

		method = "Branch predictor hardening";