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From: Paul Burton <paul@archlinuxmips.org>
To: Peter Maydell <peter.maydell@linaro.org>
Cc: Riku Voipio <riku.voipio@iki.fi>,
	QEMU Developers <qemu-devel@nongnu.org>
Subject: Re: [Qemu-devel] [PATCH] linux-user: fix ipc(SEMCTL, ...) argument handling
Date: Mon, 23 Jun 2014 23:36:58 +0100	[thread overview]
Message-ID: <20140623223658.GD4377@gmail.com> (raw)
In-Reply-To: <20140623221825.GC4377@gmail.com>

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On Mon, Jun 23, 2014 at 11:18:25PM +0100, Paul Burton wrote:
> > Also, VERIFY_READ doesn't seem right for some of the
> > semctl operations which will modify the target_semun.
> > 
> > thanks
> > -- PMM
> 
> That part I think you're right about, I'll switch to VERIFY_WRITE.

Actually no, I don't think you're right about that afterall. The
argument union itself is never modified. I imagine if it were then it
would be painful in the case of the semctl syscall where the union is
passed directly as an argument, rather than as a pointer as it is for
the ipc syscall.

What may be modified is the data pointed to by the pointers within union
semun. That is already handled by do_semctl & the translate functions it
calls.

/me is not fond of this API...

So anyway, I believe the patch is good as-is.

Thanks,
    Paul

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  parent reply	other threads:[~2014-06-23 22:37 UTC|newest]

Thread overview: 12+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-06-23 21:40 [Qemu-devel] [PATCH] linux-user: fix ipc(SEMCTL, ...) argument handling Paul Burton
2014-06-23 22:12 ` Peter Maydell
2014-06-23 22:18   ` Paul Burton
2014-06-23 22:35     ` Peter Maydell
2014-06-23 23:06       ` Paul Burton
2014-06-23 23:21         ` Peter Maydell
2014-06-23 23:53           ` Paul Burton
2014-06-24  8:19             ` Peter Maydell
2014-06-24  9:13               ` Paul Burton
2014-06-23 22:36     ` Paul Burton [this message]
2014-06-23 22:42       ` Peter Maydell
2014-06-23 23:10         ` Paul Burton

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