From: Jens Axboe <[email protected]>
To: Stefan Metzmacher <[email protected]>, [email protected]
Cc: [email protected], [email protected]
Subject: Re: [PATCH 3/6] io_uring: add support for IORING_OP_OPENAT
Date: Thu, 16 Jan 2020 17:16:43 -0700 [thread overview]
Message-ID: <[email protected]> (raw)
In-Reply-To: <[email protected]>
On 1/16/20 3:42 PM, Stefan Metzmacher wrote:
>>> I'm not sure if current->mm is needed, I just added it for completeness
>>> and as hint that io_op_defs[req->opcode].needs_mm is there and a
>>> needs_creds could also be added (if it helps with performance)
>>>
>>> Is it possible to trigger a change of current->mm from userspace?
>>>
>>> An IORING_REGISTER_CREDS would only be useful if it's possible to
>>> register a set of credentials and then use per io_uring_sqe credentials.
>>> That would also be fine for me, but I'm not sure it's needed for now.
>>
>> I think it'd be a cleaner way of doing the same thing as your patch
>> does. It seems a little odd to do this by default (having the ring
>> change personalities depending on who's using it), but from an opt-in
>> point of view, I think it makes more sense.
>>
>> That would make the IORING_REGISTER_ call something like
>> IORING_REGISTER_ADOPT_OWNER or something like that, meaning that the
>> ring would just assume the identify of the task that's calling
>> io_uring_enter().
>>
>> Note that this also has to be passed through to the io-wq handler, as
>> the mappings there are currently static as well.
>
> What's the next step here?
Not sure, need to find some time to work on this!
> I think the current state is a security problem!
>
> The inline execution either needs to change the creds temporary
> or io_uring_enter() needs a general check that the current creds match
> the creds of the ring and return -EPERM or something similar.
Hmm, if you transfer the fd to someone else, you also give them access
to your credentials etc. We could make that -EPERM, if the owner of the
ring isn't the one invoking the submit. But that doesn't really help the
SQPOLL case, which simply consumes SQE entries. There can be no checking
there.
--
Jens Axboe
next prev parent reply other threads:[~2020-01-17 0:16 UTC|newest]
Thread overview: 37+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-01-07 17:00 [PATCHSET v2 0/6] io_uring: add support for open/close Jens Axboe
2020-01-07 17:00 ` [PATCH 1/6] fs: add namei support for doing a non-blocking path lookup Jens Axboe
2020-01-25 13:15 ` Jeff Layton
2020-01-07 17:00 ` [PATCH 2/6] fs: make build_open_flags() available internally Jens Axboe
2020-01-07 17:00 ` [PATCH 3/6] io_uring: add support for IORING_OP_OPENAT Jens Axboe
2020-01-08 13:05 ` Stefan Metzmacher
2020-01-08 16:20 ` Jens Axboe
2020-01-08 16:32 ` Stefan Metzmacher
2020-01-08 16:40 ` Jens Axboe
2020-01-08 17:04 ` Stefan Metzmacher
2020-01-08 22:53 ` Jens Axboe
2020-01-08 23:03 ` Stefan Metzmacher
2020-01-08 23:05 ` Jens Axboe
2020-01-08 23:11 ` Stefan Metzmacher
2020-01-08 23:22 ` Jens Axboe
2020-01-09 10:40 ` Stefan Metzmacher
2020-01-09 21:31 ` Jens Axboe
2020-01-16 22:42 ` Stefan Metzmacher
2020-01-17 0:16 ` Jens Axboe [this message]
2020-01-07 17:00 ` [PATCH 4/6] fs: move filp_close() outside of __close_fd_get_file() Jens Axboe
2020-01-07 17:00 ` [PATCH 5/6] io-wq: add support for uncancellable work Jens Axboe
2020-01-07 17:00 ` [PATCH 6/6] io_uring: add support for IORING_OP_CLOSE Jens Axboe
2020-01-08 21:17 ` [PATCHSET v2 0/6] io_uring: add support for open/close Stefan Metzmacher
2020-01-08 22:57 ` Jens Axboe
2020-01-08 23:05 ` Stefan Metzmacher
2020-01-09 1:02 ` Jens Axboe
2020-01-09 2:03 ` Jens Axboe
2020-01-16 22:50 ` Stefan Metzmacher
2020-01-17 0:18 ` Jens Axboe
2020-01-20 12:15 ` Stefan Metzmacher
2020-01-20 13:04 ` Pavel Begunkov
2020-01-17 0:44 ` Colin Walters
2020-01-17 0:51 ` Jens Axboe
2020-01-17 9:32 ` Pavel Begunkov
2020-01-17 15:21 ` Jens Axboe
2020-01-17 22:27 ` Pavel Begunkov
2020-01-17 22:36 ` Jens Axboe
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