[PATCH 3.16 02/16] mm: cma: fix incorrect type conversion for size during dma allocation

From: Ben Hutchings
Date: Fri Mar 22 2019 - 01:23:50 EST


3.16.64-rc1 review patch. If anyone has any objections, please let me know.

------------------

From: Rohit Vaswani <rvaswani@xxxxxxxxxxxxxx>

commit 67a2e213e7e937c41c52ab5bc46bf3f4de469f6e upstream.

This was found during userspace fuzzing test when a large size dma cma
allocation is made by driver(like ion) through userspace.

show_stack+0x10/0x1c
dump_stack+0x74/0xc8
kasan_report_error+0x2b0/0x408
kasan_report+0x34/0x40
__asan_storeN+0x15c/0x168
memset+0x20/0x44
__dma_alloc_coherent+0x114/0x18c

Signed-off-by: Rohit Vaswani <rvaswani@xxxxxxxxxxxxxx>
Acked-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
Cc: Marek Szyprowski <m.szyprowski@xxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
[bwh: Backported to 3.16: cma_alloc() does not exist so only
dma_alloc_from_contiguous() needs to be changed]
Signed-off-by: Ben Hutchings <ben@xxxxxxxxxxxxxxx>
---
--- a/drivers/base/dma-contiguous.c
+++ b/drivers/base/dma-contiguous.c
@@ -313,7 +313,7 @@ static void clear_cma_bitmap(struct cma
* global one. Requires architecture specific dev_get_cma_area() helper
* function.
*/
-struct page *dma_alloc_from_contiguous(struct device *dev, int count,
+struct page *dma_alloc_from_contiguous(struct device *dev, size_t count,
unsigned int align)
{
unsigned long mask, pfn, pageno, start = 0;
@@ -327,7 +327,7 @@ struct page *dma_alloc_from_contiguous(s
if (align > CONFIG_CMA_ALIGNMENT)
align = CONFIG_CMA_ALIGNMENT;

- pr_debug("%s(cma %p, count %d, align %d)\n", __func__, (void *)cma,
+ pr_debug("%s(cma %p, count %zu, align %d)\n", __func__, (void *)cma,
count, align);

if (!count)
--- a/include/linux/dma-contiguous.h
+++ b/include/linux/dma-contiguous.h
@@ -116,7 +116,7 @@ static inline int dma_declare_contiguous
return ret;
}

-struct page *dma_alloc_from_contiguous(struct device *dev, int count,
+struct page *dma_alloc_from_contiguous(struct device *dev, size_t count,
unsigned int order);
bool dma_release_from_contiguous(struct device *dev, struct page *pages,
int count);
@@ -151,7 +151,7 @@ int dma_declare_contiguous(struct device
}

static inline
-struct page *dma_alloc_from_contiguous(struct device *dev, int count,
+struct page *dma_alloc_from_contiguous(struct device *dev, size_t count,
unsigned int order)
{
return NULL;