proc: Provide details on speculation flaw mitigations

As done with seccomp and no_new_privs, also show speculation flaw
mitigation state in /proc/$pid/status.

Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

1 files changed, 22 insertions, 0 deletions

diff --git a/fs/proc/array.c b/fs/proc/array.c
index ae2c807fd719..303c155f9b04 100644
--- a/fs/proc/array.c
+++ b/fs/proc/array.c
@@ -85,6 +85,7 @@
 #include <linux/delayacct.h>
 #include <linux/seq_file.h>
 #include <linux/pid_namespace.h>
+#include <linux/prctl.h>
 #include <linux/ptrace.h>
 #include <linux/tracehook.h>
 #include <linux/string_helpers.h>
@@ -335,6 +336,27 @@ static inline void task_seccomp(struct seq_file *m, struct task_struct *p)
 #ifdef CONFIG_SECCOMP
         seq_put_decimal_ull(m, "\nSeccomp:\t", p->seccomp.mode);
 #endif
+        seq_printf(m, "\nSpeculation Store Bypass:\t");
+        switch (arch_prctl_spec_ctrl_get(p, PR_SPEC_STORE_BYPASS)) {
+        case -EINVAL:
+                seq_printf(m, "unknown");
+                break;
+        case PR_SPEC_NOT_AFFECTED:
+                seq_printf(m, "not vulnerable");
+                break;
+        case PR_SPEC_PRCTL | PR_SPEC_DISABLE:
+                seq_printf(m, "thread mitigated");
+                break;
+        case PR_SPEC_PRCTL | PR_SPEC_ENABLE:
+                seq_printf(m, "thread vulnerable");
+                break;
+        case PR_SPEC_DISABLE:
+                seq_printf(m, "globally mitigated");
+                break;
+        default:
+                seq_printf(m, "vulnerable");
+                break;
+        }
         seq_putc(m, '\n');
 }