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From: Russell Coker <>
To: Topi Miettinen <>
Subject: Re: Access to raw memory: remove or make boolean?
Date: Tue, 25 Feb 2020 02:42:58 +1100
Message-ID: <2111138.8pYWFqxgyc@xev> (raw)
In-Reply-To: <>

On Tuesday, 25 February 2020 2:11:46 AM AEDT Topi Miettinen wrote:
> Hi,
> I made a PR 192 (
> for introducing a new boolean to disable access to raw memory devices
> (/dev/mem, /dev/kmem, /dev/mergemem, dev/oldmem, /dev/port) because on
> modern systems, direct access shouldn't be needed anymore. Chris
> PeBenito asked to propose to this list whether instead of boolean, the
> access should be removed unconditionally if it's no longer needed. I
> think boolean could be useful for those systems where this is still
> needed but still use latest reference policy.

A quick search turned up the above article from 2005 debating whether /dev/
kmem was of any use then.

./services/devicekit.te:        dev_read_raw_memory(devicekit_disk_t)
./system/init.te:       dev_rx_raw_memory(initrc_t)
./system/init.te:       dev_wx_raw_memory(initrc_t)

A quick grep of the latest policy turned up the above access to /dev/mem.  Do 
ddcprobe_t, vbetool_t, and the X server still do that?  mcelog_t, and klogd_t 
might have good uses, as might sosreport_t (don't even know what it does but 
guessing it's like klogd_t).  rpm_t should maybe transition to a different 
domain for whatever it was doing and the same for kudzo_t.  Vmware  is a bit 
ugly, so vmware_t might actually do that.  iscsi_t, mdadm_t, colord_t, and 
initrc_t should never have needed that.  hald_t, hald_mac_t and 
devicekit_disk_t might have needed it, but hopefully that was fixed a long 
time ago.

Interestingly bootloader_t doesn't have such access even though a quick 
inspection of the LILO source code shows that it still probes the boot order 
by directly reading the BIOS memory.  I guess no-one uses LILO with SE Linux.

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Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-02-24 15:11 Topi Miettinen
2020-02-24 15:42 ` Russell Coker [this message]
2020-02-24 15:56   ` Topi Miettinen
2020-02-25  0:27     ` Russell Coker
2020-02-25  8:54       ` Topi Miettinen

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