seccomp: Use PR_SPEC_FORCE_DISABLE

Use PR_SPEC_FORCE_DISABLE in seccomp() because seccomp does not allow to
widen restrictions.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
CVE-2018-3639 (x86)

Signed-off-by: Stefan Bader <stefan.bader@canonical.com>

diff --git a/kernel/seccomp.c b/kernel/seccomp.c
index cb1e2fb77ca14ce13bc94bf401b0aa46bb41b1cc..494f98e07b2d71d2b14ceb62bd351813bbd993cb 100644 (file)
--- a/kernel/seccomp.c
+++ b/kernel/seccomp.c
@@ -237,7 +237,7 @@ static inline void spec_mitigate(struct task_struct *task,
        int state = arch_prctl_spec_ctrl_get(task, which);
 
        if (state > 0 && (state & PR_SPEC_PRCTL))
-               arch_prctl_spec_ctrl_set(task, which, PR_SPEC_DISABLE);
+               arch_prctl_spec_ctrl_set(task, which, PR_SPEC_FORCE_DISABLE);
 }
 
 static inline void seccomp_assign_mode(struct task_struct *task,