prctl: Add force disable speculation

[mirror_ubuntu-artful-kernel.git] / fs / proc / array.c

diff --git a/fs/proc/array.c b/fs/proc/array.c
index 88c355574aa0afe3b1a62b371b048af8d948070e..f2555b3dbe850374aa4c506da31c4f3ec5a1e473 100644 (file)
--- a/fs/proc/array.c
+++ b/fs/proc/array.c
@@ -62,6 +62,7 @@
 #include <linux/mman.h>
 #include <linux/sched/mm.h>
 #include <linux/sched/numa_balancing.h>
+#include <linux/sched/task_stack.h>
 #include <linux/sched/task.h>
 #include <linux/sched/cputime.h>
 #include <linux/proc_fs.h>
@@ -83,6 +84,8 @@
 #include <linux/delayacct.h>
 #include <linux/seq_file.h>
 #include <linux/pid_namespace.h>
+#include <linux/nospec.h>
+#include <linux/prctl.h>
 #include <linux/ptrace.h>
 #include <linux/tracehook.h>
 #include <linux/string_helpers.h>
@@ -350,6 +353,30 @@ 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_FORCE_DISABLE:
+               seq_printf(m, "thread force mitigated");
+               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');
 }
 
@@ -421,7 +448,15 @@ static int do_task_stat(struct seq_file *m, struct pid_namespace *ns,
                 * esp and eip are intentionally zeroed out.  There is no
                 * non-racy way to read them without freezing the task.
                 * Programs that need reliable values can use ptrace(2).
+                *
+                * The only exception is if the task is core dumping because
+                * a program is not able to use ptrace(2) in that case. It is
+                * safe because the task has stopped executing permanently.
                 */
+               if (permitted && (task->flags & PF_DUMPCORE)) {
+                       eip = KSTK_EIP(task);
+                       esp = KSTK_ESP(task);
+               }
        }
 
        get_task_comm(tcomm, task);