Re: [PATCH v3 2.6.39-rc1-tip 6/26] 6: Uprobes:register/unregister probes.

[Stephen Wilson]

On Fri, Apr 01, 2011 at 08:03:38PM +0530, Srikar Dronamraju wrote:
> +int register_uprobe(struct inode *inode, loff_t offset,
> +				struct uprobe_consumer *consumer)
> +{
> +	struct prio_tree_iter iter;
> +	struct list_head try_list, success_list;
> +	struct address_space *mapping;
> +	struct mm_struct *mm, *tmpmm;
> +	struct vm_area_struct *vma;
> +	struct uprobe *uprobe;
> +	int ret = -1;
> +
> +	if (!inode || !consumer || consumer->next)
> +		return -EINVAL;
> +
> +	uprobe = uprobes_add(inode, offset);
> +	if (!uprobe)
> +		return -ENOMEM;
> +
> +	INIT_LIST_HEAD(&try_list);
> +	INIT_LIST_HEAD(&success_list);
> +	mapping = inode->i_mapping;
> +
> +	mutex_lock(&uprobes_mutex);
> +	if (uprobe->consumers) {
> +		ret = 0;
> +		goto consumers_add;
> +	}
> +
> +	spin_lock(&mapping->i_mmap_lock);
> +	vma_prio_tree_foreach(vma, &iter, &mapping->i_mmap, 0, 0) {
> +		loff_t vaddr;
> +
> +		if (!atomic_inc_not_zero(&vma->vm_mm->mm_users))
> +			continue;
> +
> +		mm = vma->vm_mm;
> +		if (!valid_vma(vma)) {
> +			mmput(mm);
> +			continue;
> +		}
> +
> +		vaddr = vma->vm_start + offset;
> +		vaddr -= vma->vm_pgoff << PAGE_SHIFT;

What happens here when someone passes an offset that is out of bounds
for the vma?  Looks like we could oops when the kernel tries to set a
breakpoint.  Perhaps check wrt ->vm_end?

-- 
steve

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