[9fans] fossil permission checking

[9fans] fossil permission checking

[Benjamin Huntsman]

I'm having some trouble setting up a terminal (which will become a cpu/auth server).
I've gotten the 9pccpuf kernel booted, and is running as the user bootes, but even from the server's console, if I type something as simple as "echo hi > /foo" I receive the message:

mounted directory forbids creation

I've basically followed the wiki pages on setting up a standalone auth/cpu server, though it's not getting me very far on the fossil side of things...  I chose all of the defaults during the install process, 

Can someone give me a quick tip as to how to set up a new cpu/fossil user that can actually write to something other than their home directory?

Also, there's not exactly a command like UNIX's sudo, is there?

Thanks in advance!

Re: [9fans] fossil permission checking

[andrey mirtchovski]

/ is indeed mounted without -c. if you want to create a directory in /
use /root. see 'nm' for how the namespace is constructed.

i believe new directories in / are frowned upon (even if created in
/root). i can't find the relevant message in the archives.

On Wed, Aug 6, 2008 at 6:10 PM, Benjamin Huntsman
<BHuntsman@mail2.cu-portland.edu> wrote:
> I'm having some trouble setting up a terminal (which will become a cpu/auth server).
> I've gotten the 9pccpuf kernel booted, and is running as the user bootes, but even from the server's console, if I type something as simple as "echo hi > /foo" I receive the message:
>
> mounted directory forbids creation
>
> I've basically followed the wiki pages on setting up a standalone auth/cpu server, though it's not getting me very far on the fossil side of things...  I chose all of the defaults during the install process,
>
> Can someone give me a quick tip as to how to set up a new cpu/fossil user that can actually write to something other than their home directory?
>
> Also, there's not exactly a command like UNIX's sudo, is there?
>
> Thanks in advance!
>
>

Re: [9fans] fossil permission checking

[Benjamin Huntsman]

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>i believe new directories in / are frowned upon

Understood, though 'bootes' or whoever has superuser-like permissions should still have unlimited abilities, right?
Or is this purely a function of the flags to mount the root?  On a side-note though, what is the preferred UNIX equivalent of /usr/local or /usr2?

However, permissions are still wrong somewhere, as I can't:
   cp /adm/timezone/US_Pacific /adm/timezone/local
per the last part of the installation instructions, which also yields a permission denied message, even while logged in under the 'out-of-the-box' user glenda.

Thanks again!


-----Original Message-----
From: 9fans-bounces@9fans.net on behalf of andrey mirtchovski
Sent: Wed 8/6/2008 5:24 PM
To: Fans of the OS Plan 9 from Bell Labs
Subject: Re: [9fans] fossil permission checking
 
/ is indeed mounted without -c. if you want to create a directory in /
use /root. see 'nm' for how the namespace is constructed.

i believe new directories in / are frowned upon (even if created in
/root). i can't find the relevant message in the archives.

On Wed, Aug 6, 2008 at 6:10 PM, Benjamin Huntsman
<BHuntsman@mail2.cu-portland.edu> wrote:
> I'm having some trouble setting up a terminal (which will become a cpu/auth server).
> I've gotten the 9pccpuf kernel booted, and is running as the user bootes, but even from the server's console, if I type something as simple as "echo hi > /foo" I receive the message:
>
> mounted directory forbids creation
>
> I've basically followed the wiki pages on setting up a standalone auth/cpu server, though it's not getting me very far on the fossil side of things...  I chose all of the defaults during the install process,
>
> Can someone give me a quick tip as to how to set up a new cpu/fossil user that can actually write to something other than their home directory?
>
> Also, there's not exactly a command like UNIX's sudo, is there?
>
> Thanks in advance!
>
>



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Re: [9fans] fossil permission checking

[Uriel]

There is no 'super-user' in Plan 9, bootes is (for the most part) a
user like any other, that just happens to be the owner of most kernel
file servers. It has no special privileges, in Plan 9 there is nothing
like root that lets you ignore file permissions and so on, the kernel
applies the same rules to everyone.

This is one of the things that were badly broken in the Unix security
model and was fixed in Plan 9. I specially recommend reading the
'Security in Plan 9' paper.

Peace

uriel

On Thu, Aug 7, 2008 at 3:01 AM, Benjamin Huntsman
<BHuntsman@mail2.cu-portland.edu> wrote:
>>i believe new directories in / are frowned upon
>
> Understood, though 'bootes' or whoever has superuser-like permissions should still have unlimited abilities, right?
> Or is this purely a function of the flags to mount the root?  On a side-note though, what is the preferred UNIX equivalent of /usr/local or /usr2?
>
> However, permissions are still wrong somewhere, as I can't:
>   cp /adm/timezone/US_Pacific /adm/timezone/local
> per the last part of the installation instructions, which also yields a permission denied message, even while logged in under the 'out-of-the-box' user glenda.
>
> Thanks again!
>
>
> -----Original Message-----
> From: 9fans-bounces@9fans.net on behalf of andrey mirtchovski
> Sent: Wed 8/6/2008 5:24 PM
> To: Fans of the OS Plan 9 from Bell Labs
> Subject: Re: [9fans] fossil permission checking
>
> / is indeed mounted without -c. if you want to create a directory in /
> use /root. see 'nm' for how the namespace is constructed.
>
> i believe new directories in / are frowned upon (even if created in
> /root). i can't find the relevant message in the archives.
>
> On Wed, Aug 6, 2008 at 6:10 PM, Benjamin Huntsman
> <BHuntsman@mail2.cu-portland.edu> wrote:
>> I'm having some trouble setting up a terminal (which will become a cpu/auth server).
>> I've gotten the 9pccpuf kernel booted, and is running as the user bootes, but even from the server's console, if I type something as simple as "echo hi > /foo" I receive the message:
>>
>> mounted directory forbids creation
>>
>> I've basically followed the wiki pages on setting up a standalone auth/cpu server, though it's not getting me very far on the fossil side of things...  I chose all of the defaults during the install process,
>>
>> Can someone give me a quick tip as to how to set up a new cpu/fossil user that can actually write to something other than their home directory?
>>
>> Also, there's not exactly a command like UNIX's sudo, is there?
>>
>> Thanks in advance!
>>
>>
>
>
>

Re: [9fans] fossil permission checking

[andrey mirtchovski]

> However, permissions are still wrong somewhere, as I can't:
>   cp /adm/timezone/US_Pacific /adm/timezone/local

/adm/timezone files are owned by the user/group 'adm', so if you want
to modify them you should add the user you're doing this as to that
group.

i believe the issue comes from the instructions assuming that one is
either serving fossil with the "don't check permissions" flag, or has
done a "disk/kfs allow" (remember that command, anybody? :)

having no user who can circumvent the file permissions is a very good
thing, i believe.

Re: [9fans] fossil permission checking

[erik quanstrom]

>>i believe new directories in / are frowned upon
>
> Understood, though 'bootes' or whoever has superuser-like permissions should still have unlimited abilities, right?

the concept in plan 9 is called the "host owner" or eve.  eve
has special abilities on the local machine.  there are 31 places where
eve is granted special excemption to normal permission checking
in /sys/src/9/^(port ip).  the reason for so many checks is that eve
is given very targeted special abilities.  it's very unlike the unix
superuser.  the fileserver, being distinct from the cpu server kernel,
knows nothing of eve.  as far as the fs is concerned, eve is just another
user.  so eve would not be special on /, which is served by the fs.  on
the other hand, /proc is typicall served by the local kernel and eve
does have special permissions here.  eve can change permissions on
most processes.  this allows eve to debug most processes running
on a cpu server.

> Or is this purely a function of the flags to mount the root?

yes.

> On a side-note though, what is the preferred UNIX equivalent of /usr/local or /usr2?

there is none.

>> Also, there's not exactly a command like UNIX's sudo, is there?

no.  there's nothing like it.  you may wish to read /sys/doc/auth.ps

- erik