[PATCH] pidfd: add ioctl to retrieve pid info

[Luca Boccassi]

On Wed, 23 Oct 2024 at 00:45, <luca.boccassi at gmail.com> wrote:
>
> On Sat, 5 Oct 2024 at 17:06, Paul Moore <paul at paul-moore.com> wrote:
> >
> > On Fri, Oct 4, 2024 at 2:48 PM Luca Boccassi <luca.boccassi at gmail.com> wrote:
> > > On Wed, 2 Oct 2024 at 15:48, Paul Moore <paul at paul-moore.com> wrote:
> > > > On Wed, Oct 2, 2024 at 10:25 AM <luca.boccassi at gmail.com> wrote:
> >
> > ...
> >
> > > > [NOTE: please CC the LSM list on changes like this]
> > > >
> > > > Thanks Luca :)
> > > >
> > > > With the addition of the LSM syscalls we've created a lsm_ctx struct
> > > > (see include/uapi/linux/lsm.h) that properly supports multiple LSMs.
> > > > The original char ptr "secctx" approach worked back when only a single
> > > > LSM was supported at any given time, but now that multiple LSMs are
> > > > supported we need something richer, and it would be good to use this
> > > > new struct in any new userspace API.
> > > >
> > > > See the lsm_get_self_attr(2) syscall for an example (defined in
> > > > security/lsm_syscalls.c but effectively implemented via
> > > > security_getselfattr() in security/security.c).
> > >
> > > Thanks for the review, makes sense to me - I had a look at those
> > > examples but unfortunately it is getting a bit beyond my (very low)
> > > kernel skills, so I've dropped the string-based security_context from
> > > v2 but without adding something else, is there someone more familiar
> > > with the LSM world that could help implementing that side?
> >
> > We are running a little short on devs/time in LSM land right now so I
> > guess I'm the only real option (not that I have any time, but you know
> > how it goes).  If you can put together the ioctl side of things I can
> > likely put together the LSM side fairly quickly - sound good?
>
> Here's a skeleton ioctl, needs lsm-specific fields to be added to the new struct, and filled in the new function:

Forgot to mention, this is based on the vfs.pidfs branch of
https://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs.git