dma_mmap() function in IOMMU-based dma-mapping implementation lacked
a check for valid range of mmap parameters (offset and buffer size), what
might have caused access beyond the allocated buffer. This patch fixes
this issue.
Signed-off-by: Marek Szyprowski <m.szyprowski@xxxxxxxxxxx>
CC: stable@xxxxxxxxxxxxxxx # v3.6+
---
arch/arm/mm/dma-mapping.c | 5 +++++
1 file changed, 5 insertions(+)
diff --git a/arch/arm/mm/dma-mapping.c b/arch/arm/mm/dma-mapping.c
index cba12f34ff77..67ae0f2ed983 100644
--- a/arch/arm/mm/dma-mapping.c
+++ b/arch/arm/mm/dma-mapping.c
@@ -1413,12 +1413,17 @@ static int arm_iommu_mmap_attrs(struct device *dev, struct vm_area_struct *vma,
unsigned long uaddr = vma->vm_start;
unsigned long usize = vma->vm_end - vma->vm_start;
struct page **pages = __iommu_get_pages(cpu_addr, attrs);
+ unsigned long nr_pages = PAGE_ALIGN(size) >> PAGE_SHIFT;
+ unsigned long off = vma->vm_pgoff;
vma->vm_page_prot = __get_dma_pgprot(attrs, vma->vm_page_prot);
if (!pages)
return -ENXIO;
+ if (off >= nr_pages || (usize >> PAGE_SHIFT) > nr_pages - off)
+ return -ENXIO;
+
do {
int ret = vm_insert_page(vma, uaddr, *pages++);
if (ret) {
--
1.9.2
--
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