Re: [PATCH v2 2/2] ssh: Add interface ssh_search_dir

Dominick Grift <[email protected]> Thu, 20 Jun 2019 17:40:21 +0200
Newsgroups	org.kernel.vger.selinux-refpolicy
Message-ID	<[email protected]>
On Thu, Jun 20, 2019 at 05:27:31PM +0200, Dominick Grift wrote:
> On Thu, Jun 20, 2019 at 06:05:57PM +0300, Alexander Miroshnichenko wrote:
> > On четверг, 20 июня 2019 г. 17:50:11 MSK, Dominick Grift wrote:
> > > On Thu, Jun 20, 2019 at 05:41:38PM +0300, Alexander Miroshnichenko wrote:
> > > > Create interface ssh_search_dir to allow ssh_server search for keys
> > > > in non-standard location.
> > > > 
> > > > Signed-off-by: Alexander Miroshnichenko <[email protected]>
> > > > ---
> > > >  policy/modules/services/ssh.if | 18 ++++++++++++++++++
> > > >  1 file changed, 18 insertions(+)
> > > > 
> > > > diff --git a/policy/modules/services/ssh.if
> > > > b/policy/modules/services/ssh.if
> > > > index 0941f133711e..51c64ded00c4 100644
> > > > --- a/policy/modules/services/ssh.if
> > > > +++ b/policy/modules/services/ssh.if
> > > > @@ -680,6 +680,24 @@ interface(`ssh_agent_exec',`
> > > >  	can_exec($1, ssh_agent_exec_t)
> > > >  ')
> > > > +########################################
> > > > +## <summary>
> > > > +##      Search for keys in non-standard location
> > > > +## </summary>
> > > > +## <param name="domain">
> > > > +##      <summary>
> > > > +##      Domain allowed access.
> > > > +##      </summary>
> > > > +## </param>
> > > > +#
> > > > +interface(`ssh_search_dir',`
> > > > +        gen_require(`
> > > > +                type sshd_t;
> > > > +        ')
> > > > +
> > > > +	allow sshd_t $1:dir search_dir_perms;
> > > 
> > > This is generally not allowed. The caller should generally be the source.
> > > Regardless of the above. Keys should be in user home directories. I
> > > wonder what specific scenario prompted you to propose this interface?
> > 
> > GIT hosting software like gitolite/gitosis/gitea manage users ssh keys and
> > store them own location like /var/lib/gitolite/.ssh . /var/lib/gitolite have
> > gitosis_var_lib_t type, /var/lib/gitolite/.ssh have gitosis_ssh_home_t type
> > (in patched policy which I want to submit).
> > If sshd does not have { search getattr } permissions to full path to ssh key
> > user fail to login.
> > Can you propose corret way to give such permissions to multiple policies?
> > It is incorrect to label /var/lib/gitolite as user_home_dir_t type, IMHO.
> 
> Yes this sucks. I would probably do the following instead:
> 
> 1. echo "ignoredirs=/var/lib/gitolite" >> /etc/selinux/semanage.conf
> 2. semodule -B && restorecon -RvF /var/lib/gitolite
> 3. gitosis_read_lib_files(sshd_t)
> 
> Dont bother with labeling /var/lib/gitolite/.ssh differently

But this is just what I would do (if were ever forced to use gitolite). Others may have different opinions.

> 
> > 
> > > > +')
> > > > +
> > > >  ########################################
> > > >  ## <summary>
> > > >  ##	Read ssh home directory content ...
> > > 
> > 
> 
> -- 
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> Dominick Grift



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