[Bug 1812451] Re: In windows host, tftp arbitrary file read vulnerability

[Peter Maydell]

** Information type changed from Private Security to Public

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https://bugs.launchpad.net/bugs/1812451

Title:
  In windows host, tftp arbitrary file read vulnerability

Status in QEMU:
  New

Bug description:
  https://github.com/qemu/qemu/blob/master/slirp/tftp.c#L343

    if (!strncmp(req_fname, "../", 3) ||
        req_fname[strlen(req_fname) - 1] == '/' ||
        strstr(req_fname, "/../")) {
        tftp_send_error(spt, 2, "Access violation", tp);
        return;
    }

  There is file path check for not allowing escape tftp directory.
  But, in windows, file path is separated by "\" backslash.
  So, guest can read arbitrary file in Windows host.

  This bug is variant of CVE-2019-2553 - Directory traversal
  vulnerability.

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