mirror of
https://mirrors.bfsu.edu.cn/git/linux.git
synced 2025-01-16 19:04:41 +08:00
25875aa71d
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: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
72 lines
1.5 KiB
C
72 lines
1.5 KiB
C
// 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)
|
|
{
|
|
return sprintf(buf, "Mitigation: __user pointer sanitization\n");
|
|
}
|
|
|
|
static unsigned int spectre_v2_state;
|
|
static unsigned int spectre_v2_methods;
|
|
|
|
void spectre_v2_update_state(unsigned int state, unsigned int method)
|
|
{
|
|
if (state > spectre_v2_state)
|
|
spectre_v2_state = state;
|
|
spectre_v2_methods |= method;
|
|
}
|
|
|
|
ssize_t cpu_show_spectre_v2(struct device *dev, struct device_attribute *attr,
|
|
char *buf)
|
|
{
|
|
const char *method;
|
|
|
|
if (spectre_v2_state == SPECTRE_UNAFFECTED)
|
|
return sprintf(buf, "%s\n", "Not affected");
|
|
|
|
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";
|
|
break;
|
|
|
|
case SPECTRE_V2_METHOD_ICIALLU:
|
|
method = "I-cache invalidation";
|
|
break;
|
|
|
|
case SPECTRE_V2_METHOD_SMC:
|
|
case SPECTRE_V2_METHOD_HVC:
|
|
method = "Firmware call";
|
|
break;
|
|
|
|
case SPECTRE_V2_METHOD_LOOP8:
|
|
method = "History overwrite";
|
|
break;
|
|
|
|
default:
|
|
method = "Multiple mitigations";
|
|
break;
|
|
}
|
|
|
|
return sprintf(buf, "Mitigation: %s\n", method);
|
|
}
|