proc: Provide details on speculation flaw mitigations

commit fae1fa0fc6cca8beee3ab8ed71d54f9a78fa3f64 upstream

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>
Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/fs/proc/array.c b/fs/proc/array.c
index 794b52a6c20dcb8545dcdb6b24f517d3c7561d07..64f3f2084f07d94967df41a04717628710a0e8f2 100644 (file)
--- a/fs/proc/array.c
+++ b/fs/proc/array.c
@@ -80,6 +80,7 @@
 #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>
@@ -345,8 +346,29 @@ static inline void task_seccomp(struct seq_file *m, struct task_struct *p)
 {
 #ifdef CONFIG_SECCOMP
        seq_put_decimal_ull(m, "Seccomp:\t", p->seccomp.mode);
-       seq_putc(m, '\n');
 #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');
 }
 
 static inline void task_context_switch_counts(struct seq_file *m,