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From: Richard Henderson <richard.henderson@linaro.org>
To: Peter Maydell <peter.maydell@linaro.org>, Eric Blake <eblake@redhat.com>
Cc: Richard Henderson <rth@twiddle.net>,
	QEMU Developers <qemu-devel@nongnu.org>
Subject: Re: [Qemu-devel] [PATCH] linux-user: Use *at functions to implement interp_prefix
Date: Tue, 13 Feb 2018 09:22:06 -0800	[thread overview]
Message-ID: <0d1c9458-0ab9-cb9e-aee4-9e70f16c9c03@linaro.org> (raw)
In-Reply-To: <CAFEAcA_NXwhfJjJnihZdCHAL7A-ZntuNDgrpPkQQDycuMOkdgw@mail.gmail.com>

On 02/13/2018 08:50 AM, Peter Maydell wrote:
> On 13 February 2018 at 16:43, Peter Maydell <peter.maydell@linaro.org> wrote:
>> OTOH, maybe we should just go ahead without weird games with dup2 and
>> see whether any real code gets confused...
> 
> Here's some real-world code that would break with this patch
> as it stands, though dup2 games wouldn't be the fix in this case:
>  https://github.com/xinetd-org/xinetd/blob/master/xinetd/init.c#L79
> 
> (it iterates through all fds above 2 closing them, and we don't
> protect against the guest being able to perform syscalls on
> interp_dirfd)

Hmm.  I suppose we could maintain a fd_set of valid guest fd's, and check every
guest operation vs that set.  Or special-case interp_dirfd with EBADF.

Thoughts before I attempt either?


r~

      reply	other threads:[~2018-02-13 17:22 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-01-28 22:15 [Qemu-devel] [PATCH] linux-user: Use *at functions to implement interp_prefix Richard Henderson
2018-01-28 22:20 ` no-reply
2018-02-13 12:12 ` Peter Maydell
2018-02-13 15:31   ` Richard Henderson
2018-02-13 16:38     ` Eric Blake
2018-02-13 16:43       ` Peter Maydell
2018-02-13 16:50         ` Peter Maydell
2018-02-13 17:22           ` Richard Henderson [this message]

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