* [PATCH v2] drivers: dma-mapping: Do not leave an invalid area->pages pointer in dma_common_contiguous_remap()
@ 2017-05-03 14:57 Catalin Marinas
2017-05-03 15:19 ` Greg Kroah-Hartman
2017-05-25 13:30 ` Greg Kroah-Hartman
0 siblings, 2 replies; 3+ messages in thread
From: Catalin Marinas @ 2017-05-03 14:57 UTC (permalink / raw)
To: Greg Kroah-Hartman
Cc: linux-kernel, linux-arm-kernel, Andrzej Hajda, Laura Abbott,
Robin Murphy
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 44176bb38fa4
("arm64: Add support for DMA_ATTR_FORCE_CONTIGUOUS to IOMMU").
Fixes: 513510ddba96 ("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>
---
Greg,
Please merge this patch via your tree (and therefore I haven't added
your ack). Thanks.
Changes since v1:
- Kept the original comment near the dma_common_pages_remap() function
- Added acks/reviews
drivers/base/dma-mapping.c | 33 ++++++++++++++++++++++++---------
1 file changed, 24 insertions(+), 9 deletions(-)
diff --git a/drivers/base/dma-mapping.c b/drivers/base/dma-mapping.c
index efd71cf4fdea..ac224de462f6 100644
--- a/drivers/base/dma-mapping.c
+++ b/drivers/base/dma-mapping.c
@@ -273,6 +273,24 @@ 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
@@ -283,17 +301,12 @@ 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;
}
@@ -308,7 +321,7 @@ void *dma_common_contiguous_remap(struct page *page, size_t size,
{
int i;
struct page **pages;
- void *ptr;
+ struct vm_struct *area;
unsigned long pfn;
pages = kmalloc(sizeof(struct page *) << get_order(size), GFP_KERNEL);
@@ -318,11 +331,13 @@ void *dma_common_contiguous_remap(struct page *page, size_t size,
for (i = 0, pfn = page_to_pfn(page); i < (size >> PAGE_SHIFT); i++)
pages[i] = pfn_to_page(pfn + 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;
}
/*
^ permalink raw reply related [flat|nested] 3+ messages in thread
* Re: [PATCH v2] drivers: dma-mapping: Do not leave an invalid area->pages pointer in dma_common_contiguous_remap()
2017-05-03 14:57 [PATCH v2] drivers: dma-mapping: Do not leave an invalid area->pages pointer in dma_common_contiguous_remap() Catalin Marinas
@ 2017-05-03 15:19 ` Greg Kroah-Hartman
2017-05-25 13:30 ` Greg Kroah-Hartman
1 sibling, 0 replies; 3+ messages in thread
From: Greg Kroah-Hartman @ 2017-05-03 15:19 UTC (permalink / raw)
To: Catalin Marinas
Cc: linux-kernel, linux-arm-kernel, Andrzej Hajda, Laura Abbott,
Robin Murphy
On Wed, May 03, 2017 at 03:57:48PM +0100, Catalin Marinas wrote:
> 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 44176bb38fa4
> ("arm64: Add support for DMA_ATTR_FORCE_CONTIGUOUS to IOMMU").
>
> Fixes: 513510ddba96 ("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>
> ---
>
> Greg,
>
> Please merge this patch via your tree (and therefore I haven't added
> your ack). Thanks.
Ok, will queue it up after 4.12-rc1 is out.
thanks,
greg k-h
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [PATCH v2] drivers: dma-mapping: Do not leave an invalid area->pages pointer in dma_common_contiguous_remap()
2017-05-03 14:57 [PATCH v2] drivers: dma-mapping: Do not leave an invalid area->pages pointer in dma_common_contiguous_remap() Catalin Marinas
2017-05-03 15:19 ` Greg Kroah-Hartman
@ 2017-05-25 13:30 ` Greg Kroah-Hartman
1 sibling, 0 replies; 3+ messages in thread
From: Greg Kroah-Hartman @ 2017-05-25 13:30 UTC (permalink / raw)
To: Catalin Marinas
Cc: linux-kernel, linux-arm-kernel, Andrzej Hajda, Laura Abbott,
Robin Murphy
On Wed, May 03, 2017 at 03:57:48PM +0100, Catalin Marinas wrote:
> 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 44176bb38fa4
> ("arm64: Add support for DMA_ATTR_FORCE_CONTIGUOUS to IOMMU").
>
> Fixes: 513510ddba96 ("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>
> ---
>
> Greg,
>
> Please merge this patch via your tree (and therefore I haven't added
> your ack). Thanks.
I just tried to, but it doesn't apply to 4.12-rc2 :(
Can you refresh this and resend?
thanks,
greg k-h
^ permalink raw reply [flat|nested] 3+ messages in thread
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2017-05-03 14:57 [PATCH v2] drivers: dma-mapping: Do not leave an invalid area->pages pointer in dma_common_contiguous_remap() Catalin Marinas
2017-05-03 15:19 ` Greg Kroah-Hartman
2017-05-25 13:30 ` Greg Kroah-Hartman
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