Date: Fri, 31 Jan 2014 12:34:48 +0000 (GMT) From: Robert Watson <rwatson@FreeBSD.org> To: Alexander Leidinger <Alexander@Leidinger.net> Cc: svn-src-head@freebsd.org, svn-src-all@freebsd.org, Gleb Smirnoff <glebius@FreeBSD.org>, src-committers@freebsd.org, James Gritton <jamie@freebsd.org> Subject: Re: svn commit: r261266 - in head: sys/dev/drm sys/kern sys/sys usr.sbin/jail Message-ID: <alpine.BSF.2.00.1401311231490.36707@fledge.watson.org> In-Reply-To: <20140129222210.0000711f@unknown> References: <201401291341.s0TDfDcB068211@svn.freebsd.org> <20140129134344.GW66160@FreeBSD.org> <52E906CD.9050202@freebsd.org> <20140129222210.0000711f@unknown>
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On Wed, 29 Jan 2014, Alexander Leidinger wrote: >> It does. I included a warning in jail.8 that this will pretty much undo >> jail security. There are still reasons some may want to do this, but it's >> definitely not for everyone or even most people. > > It only "unjails" (= basically the same security level as the jail-host with > the added benefit of the flexibility of a jail like easy moving from one > system to another) the jail which has this flag set. All other jails without > the flag can not "escape" to the host. > > I also have to add that just setting this flag does not give access to the > host, you also have to configure a non-default devfs rule for this jail (to > have the devices appear in the jail). This is not correct: devices do not need to be delegated in devfs for PRIV_IO to allow bypass of the Jail security model, due to sysarch() and the Linux-emulated equivalent, which turn out direct I/O access from a user process without use of a device node. Frankly, I'd like to see this backed out and not reintroduced. If it must be retained, then it needs a much more clear warning that enabling this feature disables Jail's security model. Don't use the word 'obviate', instead explicitly state that root within the jail can escape the jail. Roberthome | help
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