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

Mickaël Salaün
2021-10-08T10:15:50Z

On 07/10/2021 21:25, Kees Cook wrote:
> 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.

Ok, I'll rename this sysctl.

>
> With that renamed, I think it looks good! I'm looking forward to
> interpreters using this. :)
>
> Acked-by: Kees Cook <keescook@chromium.org>
>