On Fri, Mar 15, 2024 at 2:10 PM Christian Göttsche
<cgzones@xxxxxxxxxxxxxx> wrote:
>
> Add a new hook guarding instantiations of programs with executable
> stack. They are being warned about since commit 47a2ebb7f505 ("execve:
> warn if process starts with executable stack"). Lets give LSMs the
> ability to control their presence on a per application basis.
>
> Signed-off-by: Christian Göttsche <cgzones@xxxxxxxxxxxxxx>
> ---
> fs/exec.c | 4 ++++
> include/linux/lsm_hook_defs.h | 1 +
> include/linux/security.h | 6 ++++++
> security/security.c | 13 +++++++++++++
> 4 files changed, 24 insertions(+)
Looking at the commit referenced above, I'm guessing the existing
security_file_mprotect() hook doesn't catch this?
> diff --git a/fs/exec.c b/fs/exec.c
> index 8cdd5b2dd09c..e6f9e980c6b1 100644
> --- a/fs/exec.c
> +++ b/fs/exec.c
> @@ -829,6 +829,10 @@ int setup_arg_pages(struct linux_binprm *bprm,
> BUG_ON(prev != vma);
>
> if (unlikely(vm_flags & VM_EXEC)) {
> + ret = security_vm_execstack();
> + if (ret)
> + goto out_unlock;
> +
> pr_warn_once("process '%pD4' started with executable stack\n",
> bprm->file);
> }
Instead of creating a new LSM hook, have you considered calling the
existing security_file_mprotect() hook? The existing LSM controls
there may not be a great fit in this case, but I'd like to hear if
you've tried that, and if you have, what made you decide a new hook
was the better option?
--
paul-moore.com
