nospec: Allow getting/setting on non-current task

[mirror_ubuntu-artful-kernel.git] / kernel / sys.c

diff --git a/kernel/sys.c b/kernel/sys.c
index 2855ee73acd0ef9f62699ff669659e045df84422..01df5c4b252fdf7ee91cc2610f0651fca0032c04 100644 (file)
--- a/kernel/sys.c
+++ b/kernel/sys.c
@@ -60,6 +60,8 @@
 #include <linux/uidgid.h>
 #include <linux/cred.h>
 
+#include <linux/nospec.h>
+
 #include <linux/kmsg_dump.h>
 /* Move somewhere else to avoid recompiling? */
 #include <generated/utsrelease.h>
@@ -1131,6 +1133,21 @@ out:
 
 DECLARE_RWSEM(uts_sem);
 
+#ifdef COMPAT_UTS_MACHINE
+static char compat_uts_machine[__OLD_UTS_LEN+1] = COMPAT_UTS_MACHINE;
+
+static int __init parse_compat_uts_machine(char *arg)
+{
+       strncpy(compat_uts_machine, arg, __OLD_UTS_LEN);
+       compat_uts_machine[__OLD_UTS_LEN] = 0;
+       return 0;
+}
+early_param("compat_uts_machine", parse_compat_uts_machine);
+
+#undef COMPAT_UTS_MACHINE
+#define COMPAT_UTS_MACHINE compat_uts_machine
+#endif
+
 #ifdef COMPAT_UTS_MACHINE
 #define override_architecture(name) \
        (personality(current->personality) == PER_LINUX32 && \
@@ -2187,6 +2204,17 @@ static int propagate_has_child_subreaper(struct task_struct *p, void *data)
        return 1;
 }
 
+int __weak arch_prctl_spec_ctrl_get(struct task_struct *t, unsigned long which)
+{
+       return -EINVAL;
+}
+
+int __weak arch_prctl_spec_ctrl_set(struct task_struct *t, unsigned long which,
+                                   unsigned long ctrl)
+{
+       return -EINVAL;
+}
+
 SYSCALL_DEFINE5(prctl, int, option, unsigned long, arg2, unsigned long, arg3,
                unsigned long, arg4, unsigned long, arg5)
 {
@@ -2389,6 +2417,16 @@ SYSCALL_DEFINE5(prctl, int, option, unsigned long, arg2, unsigned long, arg3,
        case PR_GET_FP_MODE:
                error = GET_FP_MODE(me);
                break;
+       case PR_GET_SPECULATION_CTRL:
+               if (arg3 || arg4 || arg5)
+                       return -EINVAL;
+               error = arch_prctl_spec_ctrl_get(me, arg2);
+               break;
+       case PR_SET_SPECULATION_CTRL:
+               if (arg4 || arg5)
+                       return -EINVAL;
+               error = arch_prctl_spec_ctrl_set(me, arg2, arg3);
+               break;
        default:
                error = -EINVAL;
                break;