On Tue, May 08, 2012 at 06:40:16PM +0400, Vladimir Murzin wrote:
> From: Vladimir Murzin <murzin.v@gmail>
>
> The current get_unmapped_area code calls the f_ops->get_unmapped_area or
> the arch's one (via the mm) only when check for TASK_SIZE is passed. However,
> generic code and some arches do the same check in their a_g_u_a implementation.
>
> This series of patches fix the check order for TASK_SIZE in archs'
> get_unmapped_area() implementations, and then removes extra check in
> high-level get_unmapped_area().
Do we even need this check in arch code? AFAICS it's already checked in
get_unmapped_area(), and this will be called prior to any
arch_get_unmapped_area() implementation. Given that this is a potential
security issue, please check my analysis of this.
unsigned long
get_unmapped_area(struct file *file, unsigned long addr, unsigned long len,
unsigned long pgoff, unsigned long flags)
{
...
/* Careful about overflows.. */
if (len > TASK_SIZE)
return -ENOMEM;
get_area = current->mm->get_unmapped_area;
if (file && file->f_op && file->f_op->get_unmapped_area)
get_area = file->f_op->get_unmapped_area;
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