From: Jens Axboe <[email protected]>
To: Josh Triplett <[email protected]>
Cc: [email protected], [email protected]
Subject: Re: [PATCH 6/6] io_uring: allow specific fd for IORING_OP_ACCEPT
Date: Wed, 4 Mar 2020 12:09:14 -0700 [thread overview]
Message-ID: <[email protected]> (raw)
In-Reply-To: <20200304190223.GA16251@localhost>
On 3/4/20 12:02 PM, Josh Triplett wrote:
> On Wed, Mar 04, 2020 at 11:00:16AM -0700, Jens Axboe wrote:
>> sqe->len can be set to a specific fd we want to use for accept4(), so
>> it uses that one instead of just assigning a free unused one.
> [...]
>> + accept->open_fd = READ_ONCE(sqe->len);
>> + if (!accept->open_fd)
>> + accept->open_fd = -1;
>
> 0 is a valid file descriptor. I realize that it seems unlikely, but I
> went to a fair bit of trouble in my patch series to ensure that
> userspace could use any valid file descriptor openat2, without a corner
> case like "you can't open as file descriptor 0", even though it would
> have been more convenient to just say "if you pass a non-zero fd in
> open_how". Please consider accepting a flag to determine the validity of
> open_fd.
Heh, I actually just changed this, just added that as a temporary hack to
verify that things were working. Now SOCK_SPECIFIC_FD is required, and we
just gate on that. OP_ACCEPT disallowed fd != 0 before, so we continue
to do that if SOCK_SPECIFIC_FD isn't set:
https://git.kernel.dk/cgit/linux-block/log/?h=io_uring-fd-select
top two patches.
--
Jens Axboe
next prev parent reply other threads:[~2020-03-04 19:09 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-03-04 18:00 [PATCHSET v2 0/6] Support selectable file descriptors Jens Axboe
2020-03-04 18:00 ` [PATCH 1/6] fs: openat2: Extend open_how to allow userspace-selected fds Jens Axboe
2020-03-04 18:00 ` [PATCH 2/6] io_uring: move CLOSE req->file checking into handler Jens Axboe
2020-03-04 18:00 ` [PATCH 3/6] io_uring: move read/write side file based prep into op handler Jens Axboe
2020-03-04 18:00 ` [PATCH 4/6] io_uring: support deferred retrival of file from fd Jens Axboe
2020-03-04 18:00 ` [PATCH 5/6] net: allow specific fd selection for __sys_accept4_file() Jens Axboe
2020-03-04 18:00 ` [PATCH 6/6] io_uring: allow specific fd for IORING_OP_ACCEPT Jens Axboe
2020-03-04 19:02 ` Josh Triplett
2020-03-04 19:09 ` Jens Axboe [this message]
2020-03-04 19:51 ` Josh Triplett
2020-03-04 19:03 ` [PATCHSET v2 0/6] Support selectable file descriptors Josh Triplett
2020-03-04 19:10 ` Jens Axboe
2020-03-04 19:28 ` Jeff Layton
2020-03-04 19:50 ` Jens Axboe
2020-03-04 19:56 ` Josh Triplett
2020-03-04 20:00 ` Jens Axboe
2020-03-04 20:09 ` Josh Triplett
2020-03-04 20:14 ` Jens Axboe
2020-03-09 20:33 ` Stefan Metzmacher
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