summaryrefslogtreecommitdiff
path: root/arch
diff options
context:
space:
mode:
authorRussell King (Oracle) <rmk+kernel@armlinux.org.uk>2022-03-07 22:28:32 +0300
committerRussell King (Oracle) <rmk+kernel@armlinux.org.uk>2022-03-08 17:46:08 +0300
commit25875aa71dfefd1959f07e626c4d285b88b27ac2 (patch)
tree85333d5e2e4f143773dc9e455c156a8ad73c3afa /arch
parentb9baf5c8c5c356757f4f9d8180b5e9d234065bc3 (diff)
downloadlinux-25875aa71dfefd1959f07e626c4d285b88b27ac2.tar.xz
ARM: include unprivileged BPF status in Spectre V2 reporting
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>
Diffstat (limited to 'arch')
-rw-r--r--arch/arm/kernel/spectre.c13
1 files changed, 13 insertions, 0 deletions
diff --git a/arch/arm/kernel/spectre.c b/arch/arm/kernel/spectre.c
index ade967f18d06..e7fea962d632 100644
--- a/arch/arm/kernel/spectre.c
+++ b/arch/arm/kernel/spectre.c
@@ -1,9 +1,19 @@
// 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";