--behdad http://behdad.org/ ---------- Forwarded message ---------- Date: Fri, 10 Jun 2005 12:42:38 -0400 From: Patrick Lam <plam@xxxxxxx> To: Behdad Esfahbod <behdad> Subject: Re: Re: [patch]: mmapping FontConfig data structures Behdad Esfahbod wrote: > You better use O_EXCL anyway. Just in case two copies of fc-mmap > happen to run in parallel, or something. Done. > How is fc-mmap supposed to be called BTW? Why not dump the cache > in the library if it doesn't exist? Just run fc-mmap/fc-mmap (it has a few options, but you don't need any to successfully run.) What do you mean by the library? > I don't know the code myself. And have not tested. Try manually making a > symlink from the name of your file to be created and have it point to > another existing file ... and see what your code does to it. (Imagine > someone malicious making a symlink pointing to your password database and > waiting for someone to run this routine as root to cause a simple denial > of service.) Here's what I do now: unlink (FcMmapFilename()); fd = open(FcMmapFilename(), O_RDWR | O_CREAT | O_TRUNC | O_EXCL, 0600); if (fd == -1) return FcFalse; Is that sufficient? What I meant by 'just hanging around' was that someone could modify the file and cause arbitrary stuff to be read into memory; taking a CRC would prevent that. If the CRC is not useful, then I won't take it. pat
