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    Subject[PATCH] (2.6.x) toshiba_acpi needs copy_from_user (fixes oops)
    On kernels with the 4G/4G patch (like some of the recent kernels in
    Fedora Core 2 development), writing stuff to the /proc/acpi/toshiba/*
    files causes an oops. As it turns out, this is because the driver is
    accessing userspace data without first doing copy_from_user(). IOW, this
    is a bug in toshiba_acpi, not a bug in the 4G/4G patch.

    Here's a patch to fix this bug. I've tested it on 2.6.4 + some patches
    from the FC kernels (including the 4G/4G patch) and it fixes my oopses.
    I have also tested it against vanilla 2.6.4 and I haven't encountered
    any regressions.

    If there are any problems with this patch, let me know.

    -Barry K. Nathan <barryn@pobox.com>


    diff -ruN linux-2.6.4/drivers/acpi/toshiba_acpi.c linux-2.6.4-bkn1/drivers/acpi/toshiba_acpi.c
    --- linux-2.6.4/drivers/acpi/toshiba_acpi.c 2004-03-12 21:31:59.000000000 -0800
    +++ linux-2.6.4-bkn1/drivers/acpi/toshiba_acpi.c 2004-03-12 22:27:07.000000000 -0800
    @@ -41,6 +41,7 @@
    #include <linux/init.h>
    #include <linux/types.h>
    #include <linux/proc_fs.h>
    +#include <asm/uaccess.h>

    #include <acpi/acpi_drivers.h>

    @@ -269,10 +270,18 @@
    }

    static int
    -dispatch_write(struct file* file, const char* buffer, unsigned long count,
    - ProcItem* item)
    +dispatch_write(struct file* file, const char __user *buffer,
    + unsigned long count, ProcItem* item)
    {
    - return item->write_func(buffer, count);
    + char str[48] = {'\0'};
    +
    + if (count > sizeof(str) - 1)
    + return count;
    +
    + if (copy_from_user(str, buffer, count))
    + return -EFAULT;
    +
    + return item->write_func(str, count);
    }

    static char*
    -
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