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: Laura Abbott <[email protected]>
Cc: Greg Kroah-Hartman <[email protected]>
Reported-by: Andrzej Hajda <[email protected]>
Signed-off-by: Catalin Marinas <[email protected]>
---
This is for correctness since once the arm64's mmap and get_sgtable ops
are fixed for DMA_ATTR_FORCE_CONTIGUOUS, we would no longer see the
issue. Anyway, it's better to get this fixed in case others trip over a
similar issue. I added a "Fixes" tag for completeness but I'm not sure
it's worth back-porting.
drivers/base/dma-mapping.c | 29 ++++++++++++++++++++++-------
1 file changed, 22 insertions(+), 7 deletions(-)
diff --git a/drivers/base/dma-mapping.c b/drivers/base/dma-mapping.c
index efd71cf4fdea..ab7071041141 100644
--- a/drivers/base/dma-mapping.c
+++ b/drivers/base/dma-mapping.c
@@ -277,8 +277,8 @@ EXPORT_SYMBOL(dma_common_mmap);
* remaps an array of PAGE_SIZE pages into another vm_area
* Cannot be used in non-sleeping contexts
*/
-void *dma_common_pages_remap(struct page **pages, size_t size,
- unsigned long vm_flags, pgprot_t prot,
+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;
@@ -287,13 +287,26 @@ void *dma_common_pages_remap(struct page **pages, size_t size,
if (!area)
return NULL;
- area->pages = pages;
-
if (map_vm_area(area, prot, pages)) {
vunmap(area->addr);
return NULL;
}
+ return area;
+}
+
+void *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 = __dma_common_pages_remap(pages, size, vm_flags, prot, caller);
+ if (!area)
+ return NULL;
+
+ area->pages = pages;
+
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;
}
/*
On Tue, Apr 25, 2017 at 07:22:23PM +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: Laura Abbott <[email protected]>
> Cc: Greg Kroah-Hartman <[email protected]>
> Reported-by: Andrzej Hajda <[email protected]>
> Signed-off-by: Catalin Marinas <[email protected]>
Small correction on the subject, the prefix should be something like:
drivers: dma-mapping:
It's not an arm64 patch.
--
Catalin
On 04/25/2017 11:22 AM, 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: Laura Abbott <[email protected]>
> Cc: Greg Kroah-Hartman <[email protected]>
> Reported-by: Andrzej Hajda <[email protected]>
> Signed-off-by: Catalin Marinas <[email protected]>
Acked-by: Laura Abbott <[email protected]>
> ---
>
> This is for correctness since once the arm64's mmap and get_sgtable ops
> are fixed for DMA_ATTR_FORCE_CONTIGUOUS, we would no longer see the
> issue. Anyway, it's better to get this fixed in case others trip over a
> similar issue. I added a "Fixes" tag for completeness but I'm not sure
> it's worth back-porting.
>
> drivers/base/dma-mapping.c | 29 ++++++++++++++++++++++-------
> 1 file changed, 22 insertions(+), 7 deletions(-)
>
> diff --git a/drivers/base/dma-mapping.c b/drivers/base/dma-mapping.c
> index efd71cf4fdea..ab7071041141 100644
> --- a/drivers/base/dma-mapping.c
> +++ b/drivers/base/dma-mapping.c
> @@ -277,8 +277,8 @@ EXPORT_SYMBOL(dma_common_mmap);
> * remaps an array of PAGE_SIZE pages into another vm_area
> * Cannot be used in non-sleeping contexts
> */
> -void *dma_common_pages_remap(struct page **pages, size_t size,
> - unsigned long vm_flags, pgprot_t prot,
> +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;
> @@ -287,13 +287,26 @@ void *dma_common_pages_remap(struct page **pages, size_t size,
> if (!area)
> return NULL;
>
> - area->pages = pages;
> -
> if (map_vm_area(area, prot, pages)) {
> vunmap(area->addr);
> return NULL;
> }
>
> + return area;
> +}
> +
> +void *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 = __dma_common_pages_remap(pages, size, vm_flags, prot, caller);
> + if (!area)
> + return NULL;
> +
> + area->pages = pages;
> +
> 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;
> }
>
> /*
>
On Tue, Apr 25, 2017 at 07:25:49PM +0100, Catalin Marinas wrote:
> On Tue, Apr 25, 2017 at 07:22:23PM +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: Laura Abbott <[email protected]>
> > Cc: Greg Kroah-Hartman <[email protected]>
> > Reported-by: Andrzej Hajda <[email protected]>
> > Signed-off-by: Catalin Marinas <[email protected]>
>
> Small correction on the subject, the prefix should be something like:
>
> drivers: dma-mapping:
>
> It's not an arm64 patch.
If you want to take it through your tree:
Acked-by: Greg Kroah-Hartman <[email protected]>
otherwise feel free to resend it with a fixed subject line and I can
take it :)
thanks,
greg k-h