Re: [PATCH 14/19] fs: Permit FIBMAP for users with CAP_SYS_RAWIO in s_user_ns

From	"Serge E. Hallyn" <serge.hallyn@ubuntu.com>
Newsgroups	linux.kernel
Subject	Re: [PATCH 14/19] fs: Permit FIBMAP for users with CAP_SYS_RAWIO in s_user_ns
Date	2015-12-05 00:50 +0100
Message-ID	<qC8gV-Xi-15@gated-at.bofh.it> (permalink)
References	(2 earlier) <qC43D-6Pk-11@gated-at.bofh.it> <qC4Q2-7mV-17@gated-at.bofh.it> <qC4Q2-7mV-15@gated-at.bofh.it> <qC5sK-7Aa-7@gated-at.bofh.it> <qC7NT-MQ-1@gated-at.bofh.it>
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On Fri, Dec 04, 2015 at 06:11:52PM -0500, Theodore Ts'o wrote:
> On Fri, Dec 04, 2015 at 02:45:32PM -0600, Seth Forshee wrote:
> > On Fri, Dec 04, 2015 at 02:07:36PM -0600, Serge E. Hallyn wrote:
> > > Heh, I was looking over http://www.gossamer-threads.com/lists/linux/kernel/103611
> > > a little while ago :)  The same question was asked 16 years ago.  Apparently
> > > the answer then was that it was easier than fixing the code.
> > 
> > So it seems then that either it still isn't safe and so unprivileged
> > users shouldn't be allowed to do it at all, or else it's safe and we
> > should drop the requirement completely. I can't say which is right,
> > unfortunately.
> 
> It may not have been safe 16 years agoo, but giving invalid arguments
> to FIBMAP is safe for ext4 and ext2.  This is the sort of thing that
> tools like trinity should and does test for, so I think it should be
> fine to remove the root check for FIBMAP.

Seth, can I tempt you into sending a standalone patch to remove that? :)

-serge
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Thread

[PATCH 14/19] fs: Permit FIBMAP for users with CAP_SYS_RAWIO in s_user_ns Seth Forshee <seth.forshee@canonical.com> - 2015-12-02 16:50 +0100
  Re: [PATCH 14/19] fs: Permit FIBMAP for users with CAP_SYS_RAWIO in  s_user_ns "Serge E. Hallyn" <serge@hallyn.com> - 2015-12-04 21:10 +0100
    Re: [PATCH 14/19] fs: Permit FIBMAP for users with CAP_SYS_RAWIO in  s_user_ns Seth Forshee <seth.forshee@canonical.com> - 2015-12-04 21:50 +0100
      Re: [PATCH 14/19] fs: Permit FIBMAP for users with CAP_SYS_RAWIO in  s_user_ns Theodore Ts'o <tytso@mit.edu> - 2015-12-05 00:20 +0100
        Re: [PATCH 14/19] fs: Permit FIBMAP for users with CAP_SYS_RAWIO in  s_user_ns "Serge E. Hallyn" <serge.hallyn@ubuntu.com> - 2015-12-05 00:50 +0100
          Re: [PATCH 14/19] fs: Permit FIBMAP for users with CAP_SYS_RAWIO in  s_user_ns Seth Forshee <seth.forshee@canonical.com> - 2015-12-05 07:20 +0100
        Re: [PATCH 14/19] fs: Permit FIBMAP for users with CAP_SYS_RAWIO in s_user_ns Andreas Dilger <adilger@dilger.ca> - 2015-12-05 01:10 +0100
  Re: [PATCH 14/19] fs: Permit FIBMAP for users with CAP_SYS_RAWIO in  s_user_ns Theodore Ts'o <tytso@mit.edu> - 2015-12-04 21:10 +0100

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