Re: tar "features"

From: Kragen (kragenat_private)
Date: Sat Sep 26 1998 - 07:05:32 PDT

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    On Fri, 25 Sep 1998, der Mouse wrote:
    > But this sort of thing is why, quite some time ago, I added a key (I
    > picked "j") to my tar to watch for exactly this kind of thing: add j to
    > an x operation and tar will refuse to extract such things.
    
    Is this a patch you can release?
    
    Why do you provide the option of not doing this checking?
    
    >  * This code is full of potential races,
    
    That's an interesting thing to point out.  I can't count the number of
    tar files I've extracted that had world-writable directories in them.
    The races you mention exist in just ordinary tar, as well as your
    modified version, I assume.
    
    > Of course, on systems with symlink modes this will break for an archive
    > that looks like
    >
    > --x--x--x ./foo -> /etc
    > rwxrwxrwx ./foo/profile
    >
    > because it won't be able to readlink() the extracted symlink.
    
    I assume this means that you're using readlink() to tell if it's a
    symlink or not.  Can't you use lstat() and ISLNK()?  Or is ISLNK not
    portable?
    
    Kragen
    
    --
    <kragenat_private>       Kragen Sitaker     <http://www.pobox.com/~kragen/>
    The sages do not believe that making no mistakes is a blessing. They believe,
    rather, that the great virtue of man lies in his ability to correct his
    mistakes and continually make a new man of himself.  -- Wang Yang-Ming
    



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