[Libguestfs] [PATCH 1/3] New API: case-sensitive-path to return case sensitive path on NTFS 3g fs

[Matthew Booth]

On 26/10/09 12:13, Richard W.M. Jones wrote:
> On Mon, Oct 26, 2009 at 11:18:26AM +0000, Matthew Booth wrote:
>> Problem is, if you don't put the magic in you're pushing the problem on
>> to the library user.
>
> This is not true.  It's only used for the case where you are resolving
> paths given to you by Windows -- eg. coming from a Windows
> configuration file or from the Windows Registry.  The case we use it
> is precisely this: we read the Windows %systemroot% from NTLDR and
> then have to resolve that against the filesystem.  If Windows allowed
> its root filesystem to be on ext3 it would work the same way.

.. or the guestfish user who types 'cat 
win:c:\windows\system32\blah.txt' and doesn't get the result they 
intended. Essentially you need to do this in 2 cases: you read a path 
from a config file, or you're accessing a file whose location you 
already know. In either case, the additional call is just untidiness.

> In any other case, using case_sensitive_path is almost certainly
> wrong, in fact not just slow but quite likely to be insecure too.  You
> don't want a Linux config file that specifies /etc/something to
> randomly pick /etc/SOMETHING.

It's a very good point. You can fix this, though. When iterating down 
the directory structure, you'll open a file to check if it's a 
directory. At the same time, to fstatfs() to check what filesystem it's 
on. By doing this you can choose directory-by-directory whether or not 
to be case-sensitive. This should always be safe.

Matt
-- 
Matthew Booth, RHCA, RHCSS
Red Hat Engineering, Virtualisation Team

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