On Mon, Dec 07, 2015 at 12:32:06PM -0800, Kees Cook wrote:

On Sat, Dec 5, 2015 at 6:04 PM, Jann Horn [off-list ref] wrote:

[...]

quoted

-       if (ptrace_may_access(task, PTRACE_MODE_READ)) {
+       if (ptrace_may_access(task, PTRACE_MODE_READ | PTRACE_MODE_FSCREDS)) {

This should maybe use the PTRACE_MODE_READ_FSCREDS macro?

Oh, yes. I don't know how I missed that. :/

quoted

                error = ns_get_path(&ns_path, task, ns_ops);
                if (!error)
                        nd_jump_link(&ns_path);

@@ -63,7 +63,7 @@ static int proc_ns_readlink(struct dentry *dentry, char __user *buffer, int bufl
        if (!task)
                return res;

-       if (ptrace_may_access(task, PTRACE_MODE_READ)) {
+       if (ptrace_may_access(task, PTRACE_MODE_READ | PTRACE_MODE_FSCREDS)) {

same here?

Yes.