lkml.org 
[lkml]   [2020]   [Oct]   [15]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    /
    SubjectRe: For review: seccomp_user_notif(2) manual page
    From
    Date
    Hello Kees,

    On 10/1/20 1:39 AM, Kees Cook wrote:
    > On Wed, Sep 30, 2020 at 01:07:38PM +0200, Michael Kerrisk (man-pages) wrote:
    >> [...] I did :-)
    >
    > Yay! Thank you!

    You're welcome :-)

    >> [...]
    >> Overview
    >> In conventional usage of a seccomp filter, the decision about how
    >> to treat a particular system call is made by the filter itself.
    >> The user-space notification mechanism allows the handling of the
    >> system call to instead be handed off to a user-space process.
    >> The advantages of doing this are that, by contrast with the sec‐
    >> comp filter, which is running on a virtual machine inside the
    >> kernel, the user-space process has access to information that is
    >> unavailable to the seccomp filter and it can perform actions that
    >> can't be performed from the seccomp filter.
    >
    > I might clarify a bit with something like (though maybe the
    > target/supervisor paragraph needs to be moved to the start):
    >
    > This is used for performing syscalls on behalf of the target,
    > rather than having the supervisor make security policy decisions
    > about the syscall, which would be inherently race-prone. The
    > target's syscall should either be handled by the supervisor or
    > allowed to continue normally in the kernel (where standard security
    > policies will be applied).

    You, Christian, and Jann all pulled me up on this point. And thanks;
    I'm going to use some of your words above. See my reply to Jann, sent
    at about the same time as this reply. Please take a look at the text
    in my reply to Jann, and let me know what you think.

    > I'll comment more later, but I've run out of time today and I didn't see
    > anyone mention this detail yet in the existing threads... :)

    Later never came :-). But, I hope you may have comments for the
    next draft, which I will send out soon.

    Thanks,

    Michael

    --
    Michael Kerrisk
    Linux man-pages maintainer; http://www.kernel.org/doc/man-pages/
    Linux/UNIX System Programming Training: http://man7.org/training/

    \
     
     \ /
      Last update: 2020-10-15 13:35    [W:4.075 / U:0.492 seconds]
    ©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site