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From: Paolo Bonzini <pbonzini@redhat.com>
To: Paul Moore <pmoore@redhat.com>
Cc: qemu-devel@nongnu.org, otubo@linux.vnet.ibm.com
Subject: Re: [Qemu-devel] [PATCH] seccomp: add mkdir() and fchmod() to the whitelist
Date: Fri, 03 Jan 2014 21:24:57 +0100	[thread overview]
Message-ID: <52C71C99.8010401@redhat.com> (raw)
In-Reply-To: <20140103195827.7268.69658.stgit@localhost>

Il 03/01/2014 20:58, Paul Moore ha scritto:
> The PulseAudio library attempts to do a mkdir(2) and fchmod(2) on
> "/run/user/<UID>/pulse" which is currently blocked by the syscall
> filter; this patch adds the two missing syscalls to the whitelist.
> You can reproduce this problem with the following command:
> 
>  # qemu -monitor stdio -device intel-hda -device hda-duplex
> 
> If watched under strace the following syscalls are shown:
> 
>  mkdir("/run/user/0/pulse", 0700)
>  fchmod(11, 0700) [NOTE: 11 is the fd for /run/user/0/pulse]

Can fchmod be exploited to violate the sandbox (e.g. to let data escape
from a VM that ought not to have any way to communicate with the outside
world)?

Paolo

  reply	other threads:[~2014-01-03 20:25 UTC|newest]

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-01-03 19:58 [Qemu-devel] [PATCH] seccomp: add mkdir() and fchmod() to the whitelist Paul Moore
2014-01-03 20:24 ` Paolo Bonzini [this message]
2014-01-03 20:46   ` Paul Moore

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