proc: hide kernel addresses via %pK in /proc/<pid>/stack

This file is readable for the task owner.  Hide kernel addresses from
unprivileged users, leave them function names and offsets.

Signed-off-by: Konstantin Khlebnikov <khlebnikov@openvz.org>
Acked-by: Kees Cook <kees.cook@canonical.com>
Cc: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/fs/proc/base.c b/fs/proc/base.c
index d49c4b5..c3af15e 100644 (file)
--- a/fs/proc/base.c
+++ b/fs/proc/base.c
@@ -340,7 +340,7 @@ static int proc_pid_stack(struct seq_file *m, struct pid_namespace *ns,
        save_stack_trace_tsk(task, &trace);
 
        for (i = 0; i < trace.nr_entries; i++) {
-               seq_printf(m, "[<%p>] %pS\n",
+               seq_printf(m, "[<%pK>] %pS\n",
                           (void *)entries[i], (void *)entries[i]);
        }
        kfree(entries);