Re: Another day, another race - lynx 2.7.1

From: Thomas Roessler (roesslerat_private)
Date: Tue Mar 17 1998 - 10:03:34 PST

  • Next message: John Goerzen: "Re: LinCity Buffer Overflow"

    On Tue, Mar 17, 1998 at 03:39:58PM +0100, Michal Zalewski wrote:
    
    > Lynx's /tmp file creation procedure is so poor that it isn't the only
    > vunerability.
    
    > Source code details/fix:
    
    > In LYUtils.c, they written their own function to make tmp filename, called
    > tempname. How it works:
    
    > sprintf(namebuffer,"%sL%d%uTMP.html",lynx_temp_space,getpid(),counter++);
    
    Actually, lynx is using LYNX_TEMP_SPACE instead of TMPDIR,
    so setting that one to $HOME/.tmp (or whatever your
    favorite place is) should help against that temp race.
    (Yes, I know that this isn't the real fix, but it's a
    quick workaround.)
    
    
    On a related topic, H. P. Anvin's magicfilter 1.2 package
    contains yet another /tmp race.  The fix (replacing tmpnam
    && fopen by mkstemp && fdopen is trivial), so I don't
    include it.
    
    Please note that this problem is especially dangerous,
    since magicfilter will run as root on a typical
    installation.
    
    tlr
    --
    Thomas Roessler · 74a353cc0b19 · dg1ktr · http://home.pages.de/~roessler/
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