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

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 index

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-01-15 16:35 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

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