Re: [PATCH RFC v2 2/3] io_uring: add IOURING_REGISTER_RESTRICTIONS opcode

[Stefano Garzarella]

On Thu, Jul 16, 2020 at 03:26:51PM -0600, Jens Axboe wrote:
> On 7/16/20 6:48 AM, Stefano Garzarella wrote:
> > diff --git a/include/uapi/linux/io_uring.h b/include/uapi/linux/io_uring.h
> > index efc50bd0af34..0774d5382c65 100644
> > --- a/include/uapi/linux/io_uring.h
> > +++ b/include/uapi/linux/io_uring.h
> > @@ -265,6 +265,7 @@ enum {
> >     IORING_REGISTER_PROBE,
> >     IORING_REGISTER_PERSONALITY,
> >     IORING_UNREGISTER_PERSONALITY,
> > +   IORING_REGISTER_RESTRICTIONS,
> >  
> >     /* this goes last */
> >     IORING_REGISTER_LAST
> > @@ -293,4 +294,30 @@ struct io_uring_probe {
> >     struct io_uring_probe_op ops[0];
> >  };
> >  
> > +struct io_uring_restriction {
> > +   __u16 opcode;
> > +   union {
> > +           __u8 register_op; /* IORING_RESTRICTION_REGISTER_OP */
> > +           __u8 sqe_op;      /* IORING_RESTRICTION_SQE_OP */
> > +   };
> > +   __u8 resv;
> > +   __u32 resv2[3];
> > +};
> > +
> > +/*
> > + * io_uring_restriction->opcode values
> > + */
> > +enum {
> > +   /* Allow an io_uring_register(2) opcode */
> > +   IORING_RESTRICTION_REGISTER_OP,
> > +
> > +   /* Allow an sqe opcode */
> > +   IORING_RESTRICTION_SQE_OP,
> > +
> > +   /* Only allow fixed files */
> > +   IORING_RESTRICTION_FIXED_FILES_ONLY,
> > +
> > +   IORING_RESTRICTION_LAST
> > +};
> > +
> 
> Not sure I totally love this API. Maybe it'd be cleaner to have separate
> ops for this, instead of muxing it like this. One for registering op
> code restrictions, and one for disallowing other parts (like fixed
> files, etc).
> 
> I think that would look a lot cleaner than the above.
> 

I'm not sure I got your point.

Do you mean two different register ops?
For example, maybe with better names... ;-):

        IORING_REGISTER_RESTRICTIONS_OPS
        IORING_REGISTER_RESTRICTIONS_OTHERS


Or a single register op like now, and a new restriction opcode adding
also a new field in the struct io_uring_restriction?
For example:

        struct io_uring_restriction {
                __u16 opcode;
                union {
                        __u8 register_op; /* IORING_RESTRICTION_REGISTER_OP */
                        __u8 sqe_op;      /* IORING_RESTRICTION_SQE_OP */
                        __u8 restriction; /* IORING_RESTRICTION_OP */
                };
                __u8 resv;
                __u32 resv2[3];
        };

        /*
         * io_uring_restriction->opcode values
         */
        enum {
                /* Allow an io_uring_register(2) opcode */
                IORING_RESTRICTION_REGISTER_OP,

                /* Allow an sqe opcode */
                IORING_RESTRICTION_SQE_OP,

                IORING_RESTRICTION_OP,

                IORING_RESTRICTION_LAST
        };

        enum {
                /* Only allow fixed files */
                IORING_RESTRICTION_OP_FIXED_FILES_ONLY,
        };


Thanks,
Stefano