Re: [Xen-devel] [PATCH] ACPI: Prevent acpi_table_entries from falling into a infinite loop

[Andrew Cooper <andrew.cooper3@xxxxxxxxxx>]

On 03/06/14 15:51, Malcolm Crossley wrote:
> If a buggy BIOS programs an ACPI table with entry length 0 then
> acpi_table_entries gets stuck in an infinite loop.
>
> To aid debugging, report the error and exit the loop.
>
> Signed-off-by: Malcolm Crossley <malcolm.crossley@xxxxxxxxxx>

Could you put a reference to the Linux commit in the message?

Reviewed-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>

>
> diff -r 4708591d8aa8 -r af3b2493951c xen/drivers/acpi/tables.c
> --- a/xen/drivers/acpi/tables.c
> +++ b/xen/drivers/acpi/tables.c
> @@ -238,6 +238,12 @@ acpi_table_parse_entries(char *id,
>                       if (handler(entry, table_end))
>                               return -EINVAL;
>  
> +             if (entry->length == 0) {
> +                     printk(KERN_ERR PREFIX "[%4.4s:0x%02x] Invalid zero 
> length\n",
> +                            id, entry_id);
> +                     return -EINVAL;
> +             }
> +
>               entry = (struct acpi_subtable_header *)
>                   ((unsigned long)entry + entry->length);
>       }
>
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> http://lists.xen.org/xen-devel


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