Adjust arch_prctl_get/set_spec_ctrl() to operate on tasks other than
current.
This is needed both for /proc/$pid/status queries and for seccomp (since
thread-syncing can trigger seccomp in non-current threads).
Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
CVE-2018-3639 (x86)
Signed-off-by: Tyler Hicks <tyhicks@canonical.com>
Signed-off-by: Stefan Bader <stefan.bader@canonical.com>
-static int ssb_prctl_set(unsigned long ctrl)
+static int ssb_prctl_set(struct task_struct *task, unsigned long ctrl)
- bool rds = !!test_tsk_thread_flag(current, TIF_RDS);
+ bool rds = !!test_tsk_thread_flag(task, TIF_RDS);
if (ssb_mode != SPEC_STORE_BYPASS_PRCTL)
return -ENXIO;
if (ctrl == PR_SPEC_ENABLE)
if (ssb_mode != SPEC_STORE_BYPASS_PRCTL)
return -ENXIO;
if (ctrl == PR_SPEC_ENABLE)
- clear_tsk_thread_flag(current, TIF_RDS);
+ clear_tsk_thread_flag(task, TIF_RDS);
- set_tsk_thread_flag(current, TIF_RDS);
+ set_tsk_thread_flag(task, TIF_RDS);
- if (rds != !!test_tsk_thread_flag(current, TIF_RDS))
+ /*
+ * If being set on non-current task, delay setting the CPU
+ * mitigation until it is next scheduled.
+ */
+ if (task == current && rds != !!test_tsk_thread_flag(task, TIF_RDS))
speculative_store_bypass_update();
return 0;
}
speculative_store_bypass_update();
return 0;
}
-static int ssb_prctl_get(void)
+static int ssb_prctl_get(struct task_struct *task)
{
switch (ssb_mode) {
case SPEC_STORE_BYPASS_DISABLE:
return PR_SPEC_DISABLE;
case SPEC_STORE_BYPASS_PRCTL:
{
switch (ssb_mode) {
case SPEC_STORE_BYPASS_DISABLE:
return PR_SPEC_DISABLE;
case SPEC_STORE_BYPASS_PRCTL:
- if (test_tsk_thread_flag(current, TIF_RDS))
+ if (test_tsk_thread_flag(task, TIF_RDS))
return PR_SPEC_PRCTL | PR_SPEC_DISABLE;
return PR_SPEC_PRCTL | PR_SPEC_ENABLE;
default:
return PR_SPEC_PRCTL | PR_SPEC_DISABLE;
return PR_SPEC_PRCTL | PR_SPEC_ENABLE;
default:
-int arch_prctl_spec_ctrl_set(unsigned long which, unsigned long ctrl)
+int arch_prctl_spec_ctrl_set(struct task_struct *task, unsigned long which,
+ unsigned long ctrl)
{
if (ctrl != PR_SPEC_ENABLE && ctrl != PR_SPEC_DISABLE)
return -ERANGE;
switch (which) {
case PR_SPEC_STORE_BYPASS:
{
if (ctrl != PR_SPEC_ENABLE && ctrl != PR_SPEC_DISABLE)
return -ERANGE;
switch (which) {
case PR_SPEC_STORE_BYPASS:
- return ssb_prctl_set(ctrl);
+ return ssb_prctl_set(task, ctrl);
default:
return -ENODEV;
}
}
default:
return -ENODEV;
}
}
-int arch_prctl_spec_ctrl_get(unsigned long which)
+int arch_prctl_spec_ctrl_get(struct task_struct *task, unsigned long which)
{
switch (which) {
case PR_SPEC_STORE_BYPASS:
{
switch (which) {
case PR_SPEC_STORE_BYPASS:
- return ssb_prctl_get();
+ return ssb_prctl_get(task);
default:
return -ENODEV;
}
default:
return -ENODEV;
}
#define _LINUX_NOSPEC_H
#include <asm/barrier.h>
#define _LINUX_NOSPEC_H
#include <asm/barrier.h>
/**
* array_index_mask_nospec() - generate a ~0 mask when index < size, 0 otherwise
* @index: array element index
/**
* array_index_mask_nospec() - generate a ~0 mask when index < size, 0 otherwise
* @index: array element index
})
/* Speculation control prctl */
})
/* Speculation control prctl */
-int arch_prctl_spec_ctrl_get(unsigned long which);
-int arch_prctl_spec_ctrl_set(unsigned long which, unsigned long ctrl);
+int arch_prctl_spec_ctrl_get(struct task_struct *task, unsigned long which);
+int arch_prctl_spec_ctrl_set(struct task_struct *task, unsigned long which,
+ unsigned long ctrl);
#endif /* _LINUX_NOSPEC_H */
#endif /* _LINUX_NOSPEC_H */
-int __weak arch_prctl_spec_ctrl_get(unsigned long which)
+int __weak arch_prctl_spec_ctrl_get(struct task_struct *t, unsigned long which)
-int __weak arch_prctl_spec_ctrl_set(unsigned long which, unsigned long ctrl)
+int __weak arch_prctl_spec_ctrl_set(struct task_struct *t, unsigned long which,
+ unsigned long ctrl)
case PR_GET_SPECULATION_CTRL:
if (arg3 || arg4 || arg5)
return -EINVAL;
case PR_GET_SPECULATION_CTRL:
if (arg3 || arg4 || arg5)
return -EINVAL;
- error = arch_prctl_spec_ctrl_get(arg2);
+ error = arch_prctl_spec_ctrl_get(me, arg2);
break;
case PR_SET_SPECULATION_CTRL:
if (arg4 || arg5)
return -EINVAL;
break;
case PR_SET_SPECULATION_CTRL:
if (arg4 || arg5)
return -EINVAL;
- error = arch_prctl_spec_ctrl_set(arg2, arg3);
+ error = arch_prctl_spec_ctrl_set(me, arg2, arg3);
break;
default:
error = -EINVAL;
break;
default:
error = -EINVAL;