Re: [PATCH v30 04/12] landlock: Add ptrace restrictions

From: Kees Cook
Date: Fri Mar 19 2021 - 14:46:32 EST

On Tue, Mar 16, 2021 at 09:42:44PM +0100, Mickaël Salaün wrote:
> From: Mickaël Salaün <mic@xxxxxxxxxxxxxxxxxxx>
> Using ptrace(2) and related debug features on a target process can lead
> to a privilege escalation. Indeed, ptrace(2) can be used by an attacker
> to impersonate another task and to remain undetected while performing
> malicious activities. Thanks to ptrace_may_access(), various part of
> the kernel can check if a tracer is more privileged than a tracee.
> A landlocked process has fewer privileges than a non-landlocked process
> and must then be subject to additional restrictions when manipulating
> processes. To be allowed to use ptrace(2) and related syscalls on a
> target process, a landlocked process must have a subset of the target
> process's rules (i.e. the tracee must be in a sub-domain of the tracer).
> Cc: James Morris <jmorris@xxxxxxxxx>
> Cc: Kees Cook <keescook@xxxxxxxxxxxx>
> Signed-off-by: Mickaël Salaün <mic@xxxxxxxxxxxxxxxxxxx>

Reviewed-by: Kees Cook <keescook@xxxxxxxxxxxx>

Kees Cook