From: Marek Szyprowski <m.szyprowski@xxxxxxxxxxx>
3.12-stable review patch. If anyone has any objections, please let me know.
===============
commit 371f0f085f629fc0f66695f572373ca4445a67ad upstream.
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>
Signed-off-by: Russell King <rmk+kernel@xxxxxxxxxxxxxxxx>
Signed-off-by: Jiri Slaby <jslaby@xxxxxxx>
---
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 79cff8fdbaf3..f817f3064d67 100644
--- a/arch/arm/mm/dma-mapping.c
+++ b/arch/arm/mm/dma-mapping.c
@@ -1378,12 +1378,17 @@ 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) {
--
2.6.4
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