Re: [RFC PATCH bpf-next seccomp 10/12] seccomp-ebpf: Add ability to read user memory
From: Alexei Starovoitov <hidden>
Date: 2021-05-11 02:04:31
Also in:
linux-security-module
On Mon, May 10, 2021 at 12:22:47PM -0500, YiFei Zhu wrote:
+BPF_CALL_3(bpf_probe_read_user_dumpable, void *, dst, u32, size,
+ const void __user *, unsafe_ptr)
+{
+ int ret = -EPERM;
+
+ if (get_dumpable(current->mm))
+ ret = copy_from_user_nofault(dst, unsafe_ptr, size);Could you explain a bit more how dumpable flag makes it safe for unpriv? The unpriv prog is attached to the children tasks only, right? and dumpable gets cleared if euid changes?