mtime changeable on immutable files (a bug, isn't it?)

mtime changeable on immutable files (a bug, isn't it?)

[Thomas Habets]

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You can touch(1) an immutable file, which changes its mtime. Since you can't
change the permission bits of the inode, you shouldn't be able to change the
mtime, correct?

I pointed this out in september of 1999, including a patch that fixes it.
I got no reply answering if this was correct behavior or a bug back then, I'd
appreciate a reply now.

(please CC any reply to me since I'm not on the list)

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Re: mtime changeable on immutable files (a bug, isn't it?)

[Ragnar Hojland Espinosa]

On Mon, Mar 25, 2002 at 07:24:57PM +0100, Thomas Habets wrote:
> You can touch(1) an immutable file, which changes its mtime. Since you can't
> change the permission bits of the inode, you shouldn't be able to change the
> mtime, correct?

You could reason that since the immutable flag is set at i_mode, and i_mode
stores file modes, it should be legal to change the inode (mtime) as long as
you do not change the contents of the file.

Or at least that that would be the intention of chattr, if you re-read the
page:

       A  file with the i' attribute cannot be modified: it can<AD>
       not be deleted or renamed, no link can be created to  this
       file  and  no  data  can  be written to the file. Only the
       superuser can set or clear this attribute.

Even if you obviate the inode/file difference, by changing mtime you aren't
either deleting, renaming, linking or writing data to the file, so you are
consistent to the pubished documentation.
-- 
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