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drivers: dma-mapping: Do not leave an invalid area->pages pointer in dma_common_contiguous_remap()

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The dma_common_pages_remap() function allocates a vm_struct object and
initialises the pages pointer to value passed as argument. However, when
this function is called dma_common_contiguous_remap(), the pages array
is only temporarily allocated, being freed shortly after
dma_common_contiguous_remap() returns. Architecture code checking the
validity of an area->pages pointer would incorrectly dereference already
freed pointers. This has been exposed by the arm64 commit 44176bb38f
("arm64: Add support for DMA_ATTR_FORCE_CONTIGUOUS to IOMMU").

Fixes: 513510ddba ("common: dma-mapping: introduce common remapping functions")
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Reported-by: Andrzej Hajda <a.hajda@samsung.com>
Acked-by: Laura Abbott <labbott@redhat.com>
Reviewed-by: Robin Murphy <robin.murphy@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Catalin Marinas 2017-05-25 17:26:47 +01:00 committed by Greg Kroah-Hartman
parent e622ec579b
commit 1a3389ffc5
1 changed files with 24 additions and 9 deletions
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33
drivers/base/dma-mapping.c
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@ -275,6 +275,24 @@ int dma_common_mmap(struct device *dev, struct vm_area_struct *vma,
EXPORT_SYMBOL(dma_common_mmap);
#ifdef CONFIG_MMU
static struct vm_struct *__dma_common_pages_remap(struct page **pages,
size_t size, unsigned long vm_flags, pgprot_t prot,
const void *caller)
{
struct vm_struct *area;
area = get_vm_area_caller(size, vm_flags, caller);
if (!area)
return NULL;
if (map_vm_area(area, prot, pages)) {
vunmap(area->addr);
return NULL;
}
return area;
}
/*
* remaps an array of PAGE_SIZE pages into another vm_area
* Cannot be used in non-sleeping contexts
@ -285,17 +303,12 @@ void *dma_common_pages_remap(struct page **pages, size_t size,
{
struct vm_struct *area;
area = get_vm_area_caller(size, vm_flags, caller);
area = __dma_common_pages_remap(pages, size, vm_flags, prot, caller);
if (!area)
return NULL;
area->pages = pages;
if (map_vm_area(area, prot, pages)) {
vunmap(area->addr);
return NULL;
}
return area->addr;
}
@ -310,7 +323,7 @@ void *dma_common_contiguous_remap(struct page *page, size_t size,
{
int i;
struct page **pages;
void *ptr;
struct vm_struct *area;
pages = kmalloc(sizeof(struct page *) << get_order(size), GFP_KERNEL);
if (!pages)
@ -319,11 +332,13 @@ void *dma_common_contiguous_remap(struct page *page, size_t size,
for (i = 0; i < (size >> PAGE_SHIFT); i++)
pages[i] = nth_page(page, i);
ptr = dma_common_pages_remap(pages, size, vm_flags, prot, caller);
area = __dma_common_pages_remap(pages, size, vm_flags, prot, caller);
kfree(pages);
return ptr;
if (!area)
return NULL;
return area->addr;
}
/*