Re: [PATCH 3/5] uprobes: fix overflow in vma_address/find_active_uprobe

[Joe Perches <joe@perches.com>]

On Sun, 2012-07-08 at 22:30 +0200, Oleg Nesterov wrote:
> vma->vm_pgoff is "unsigned long", it should be promoted to loff_t
> before the multiplication to avoid the overflow.
[]
> diff --git a/kernel/events/uprobes.c b/kernel/events/uprobes.c
[]
> @@ -117,7 +117,7 @@ static loff_t vma_address(struct vm_area_struct *vma, loff_t offset)
>  	loff_t vaddr;
>  
>  	vaddr = vma->vm_start + offset;
> -	vaddr -= vma->vm_pgoff << PAGE_SHIFT;
> +	vaddr -= (loff_t)vma->vm_pgoff << PAGE_SHIFT;
>  
>  	return vaddr;
>  }
> @@ -1450,7 +1450,7 @@ static struct uprobe *find_active_uprobe(unsigned long bp_vaddr, int *is_swbp)
>  
>  			inode = vma->vm_file->f_mapping->host;
>  			offset = bp_vaddr - vma->vm_start;
> -			offset += (vma->vm_pgoff << PAGE_SHIFT);
> +			offset += ((loff_t)vma->vm_pgoff << PAGE_SHIFT);

It's be nice to take remove the unnecessary parenthesis
and make it consistent with the vaddr use above it too.