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From: Jens Axboe <[email protected]>
To: Eugene Syromiatnikov <[email protected]>,
	[email protected], [email protected],
	Alexander Viro <[email protected]>
Cc: [email protected], Jeff Moyer <[email protected]>,
	"Dmitry V. Levin" <[email protected]>
Subject: Re: [PATCH] io_uring: fix compat for IORING_REGISTER_FILES_UPDATE
Date: Wed, 15 Jan 2020 09:41:58 -0700	[thread overview]
Message-ID: <[email protected]> (raw)
In-Reply-To: <[email protected]>

On 1/15/20 9:35 AM, Eugene Syromiatnikov wrote:
> fds field of struct io_uring_files_update is problematic with regards
> to compat user space, as pointer size is different in 32-bit, 32-on-64-bit,
> and 64-bit user space.  In order to avoid custom handling of compat in
> the syscall implementation, make fds __u64 and use u64_to_user_ptr in
> order to retrieve it.  Also, align the field naturally and check that
> no garbage is passed there.

Good point, it's an s32 pointer so won't align nicely. But how about
just having it be:

struct io_uring_files_update {
	__u32 offset;
	__u32 resv;
	__s32 *fds;
};

which should align nicely on both 32 and 64-bit?

-- 
Jens Axboe


  reply	other threads:[~2020-01-15 16:42 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-01-15 16:35 [PATCH] io_uring: fix compat for IORING_REGISTER_FILES_UPDATE Eugene Syromiatnikov
2020-01-15 16:41 ` Jens Axboe [this message]
2020-01-15 16:50   ` Eugene Syromiatnikov
2020-01-15 16:53     ` Jens Axboe
2020-01-15 16:59       ` Eugene Syromiatnikov
2020-01-20 23:51       ` Dmitry V. Levin
2020-01-20 23:54         ` Jens Axboe

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