Re: [PATCH v13 1/3] fs: Add trusted_for(2) syscall implementation and related sysctl

Kees Cook
2021-10-07T19:25:38Z

On Thu, Oct 07, 2021 at 08:23:18PM +0200, Mickaël Salaün wrote:
> From: Mickaël Salaün <mic@linux.microsoft.com>
>
> The trusted_for() syscall enables user space tasks to check that files
> are trusted to be executed or interpreted by user space. This may allow
> script interpreters to check execution permission before reading
> commands from a file, or dynamic linkers to allow shared object loading.
> This may be seen as a way for a trusted task (e.g. interpreter) to check
> the trustworthiness of files (e.g. scripts) before extending its control
> flow graph with new ones originating from these files.
> [...]
> aio-nr & aio-max-nr
> @@ -382,3 +383,52 @@ Each "watch" costs roughly 90 bytes on a 32bit kernel, and roughly 160 bytes
> on a 64bit one.
> The current default value for max_user_watches is the 1/25 (4%) of the
> available low memory, divided for the "watch" cost in bytes.
> +
> +
> +trust_policy
> +------------

bikeshed: can we name this "trusted_for_policy"? Both "trust" and
"policy" are very general words, but "trusted_for" (after this series)
will have a distinct meaning, so "trusted_for_policy" becomes more
specific/searchable.

With that renamed, I think it looks good! I'm looking forward to
interpreters using this. :)

Acked-by: Kees Cook <keescook@chromium.org>

--
Kees Cook