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dma-coherent: fix integer overflow in the reserved-memory dma allocation 

[ Upstream commit 286c21de32b904131f8cf6a36ce40b8b0c9c5da3 ]

pageno is an int and the PAGE_SHIFT shift is done on an int,
overflowing if the memory is bigger than 2G

This can be reproduced using for example a reserved-memory of 4G

reserved-memory {
		    #address-cells = <2>;
		    #size-cells = <2>;
		    ranges;

		    reserved_dma: buffer@0 {
		        compatible = "shared-dma-pool";
		        no-map;
		        reg = <0x5 0x00000000 0x1 0x0>;
        };
};

Signed-off-by: Kevin Grandemange <kevin.grandemange@allegrodvt.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Sasha Levin <sashal@kernel.org>
This commit is contained in:
Kevin Grandemange 2020-03-12 15:41:45 +00:00 committed by Greg Kroah-Hartman
parent 960bf4e436
commit 56aaa0e8c9
1 changed files with 7 additions and 6 deletions
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13
kernel/dma/coherent.c
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@ -134,7 +134,7 @@ static void *__dma_alloc_from_coherent(struct device *dev,
spin_lock_irqsave(&mem->spinlock, flags);
if (unlikely(size > (mem->size << PAGE_SHIFT)))
if (unlikely(size > ((dma_addr_t)mem->size << PAGE_SHIFT)))
goto err;
pageno = bitmap_find_free_region(mem->bitmap, mem->size, order);
@ -144,8 +144,9 @@ static void *__dma_alloc_from_coherent(struct device *dev,
/*
* Memory was found in the coherent area.
*/
*dma_handle = dma_get_device_base(dev, mem) + (pageno << PAGE_SHIFT);
ret = mem->virt_base + (pageno << PAGE_SHIFT);
*dma_handle = dma_get_device_base(dev, mem) +
((dma_addr_t)pageno << PAGE_SHIFT);
ret = mem->virt_base + ((dma_addr_t)pageno << PAGE_SHIFT);
spin_unlock_irqrestore(&mem->spinlock, flags);
memset(ret, 0, size);
return ret;
@ -194,7 +195,7 @@ static int __dma_release_from_coherent(struct dma_coherent_mem *mem,
int order, void *vaddr)
{
if (mem && vaddr >= mem->virt_base && vaddr <
(mem->virt_base + (mem->size << PAGE_SHIFT))) {
(mem->virt_base + ((dma_addr_t)mem->size << PAGE_SHIFT))) {
int page = (vaddr - mem->virt_base) >> PAGE_SHIFT;
unsigned long flags;
@ -238,10 +239,10 @@ static int __dma_mmap_from_coherent(struct dma_coherent_mem *mem,
struct vm_area_struct *vma, void *vaddr, size_t size, int *ret)
{
if (mem && vaddr >= mem->virt_base && vaddr + size <=
(mem->virt_base + (mem->size << PAGE_SHIFT))) {
(mem->virt_base + ((dma_addr_t)mem->size << PAGE_SHIFT))) {
unsigned long off = vma->vm_pgoff;
int start = (vaddr - mem->virt_base) >> PAGE_SHIFT;
int user_count = vma_pages(vma);
unsigned long user_count = vma_pages(vma);
int count = PAGE_ALIGN(size) >> PAGE_SHIFT;
*ret = -ENXIO;