diff options
Diffstat (limited to 'arch/powerpc/kernel/security.c')
| -rw-r--r-- | arch/powerpc/kernel/security.c | 71 |
1 files changed, 71 insertions, 0 deletions
diff --git a/arch/powerpc/kernel/security.c b/arch/powerpc/kernel/security.c index b98a722da915..a8b277362931 100644 --- a/arch/powerpc/kernel/security.c +++ b/arch/powerpc/kernel/security.c @@ -10,10 +10,78 @@ #include <asm/debugfs.h> #include <asm/security_features.h> +#include <asm/setup.h> unsigned long powerpc_security_features __read_mostly = SEC_FTR_DEFAULT; +bool barrier_nospec_enabled; + +static void enable_barrier_nospec(bool enable) +{ + barrier_nospec_enabled = enable; + do_barrier_nospec_fixups(enable); +} + +void setup_barrier_nospec(void) +{ + bool enable; + + /* + * It would make sense to check SEC_FTR_SPEC_BAR_ORI31 below as well. + * But there's a good reason not to. The two flags we check below are + * both are enabled by default in the kernel, so if the hcall is not + * functional they will be enabled. + * On a system where the host firmware has been updated (so the ori + * functions as a barrier), but on which the hypervisor (KVM/Qemu) has + * not been updated, we would like to enable the barrier. Dropping the + * check for SEC_FTR_SPEC_BAR_ORI31 achieves that. The only downside is + * we potentially enable the barrier on systems where the host firmware + * is not updated, but that's harmless as it's a no-op. + */ + enable = security_ftr_enabled(SEC_FTR_FAVOUR_SECURITY) && + security_ftr_enabled(SEC_FTR_BNDS_CHK_SPEC_BAR); + + enable_barrier_nospec(enable); +} + +#ifdef CONFIG_DEBUG_FS +static int barrier_nospec_set(void *data, u64 val) +{ + switch (val) { + case 0: + case 1: + break; + default: + return -EINVAL; + } + + if (!!val == !!barrier_nospec_enabled) + return 0; + + enable_barrier_nospec(!!val); + + return 0; +} + +static int barrier_nospec_get(void *data, u64 *val) +{ + *val = barrier_nospec_enabled ? 1 : 0; + return 0; +} + +DEFINE_SIMPLE_ATTRIBUTE(fops_barrier_nospec, + barrier_nospec_get, barrier_nospec_set, "%llu\n"); + +static __init int barrier_nospec_debugfs_init(void) +{ + debugfs_create_file("barrier_nospec", 0600, powerpc_debugfs_root, NULL, + &fops_barrier_nospec); + return 0; +} +device_initcall(barrier_nospec_debugfs_init); +#endif /* CONFIG_DEBUG_FS */ + ssize_t cpu_show_meltdown(struct device *dev, struct device_attribute *attr, char *buf) { bool thread_priv; @@ -52,6 +120,9 @@ ssize_t cpu_show_spectre_v1(struct device *dev, struct device_attribute *attr, c if (!security_ftr_enabled(SEC_FTR_BNDS_CHK_SPEC_BAR)) return sprintf(buf, "Not affected\n"); + if (barrier_nospec_enabled) + return sprintf(buf, "Mitigation: __user pointer sanitization\n"); + return sprintf(buf, "Vulnerable\n"); } |