Code:  static void *arm_coherent_dma_alloc(struct device *dev, size_t size,
 	dma_addr_t *handle, gfp_t gfp, struct dma_attrs *attrs)
 {
	pgprot_t prot = __get_dma_pgprot(attrs, pgprot_kernel);
 	void *memory;
 
 	if (dma_alloc_from_coherent(dev, size, handle, &memory))
		return memory;

	return __dma_alloc(dev, size, handle, gfp, prot, true,
			   __builtin_return_address(0));
}

Vulnerability Type: +Priv 
CWE ID: CWE-264
Summary: arch/arm/mm/dma-mapping.c in the Linux kernel before 3.13 on ARM platforms, as used in Android before 2016-08-05 on Nexus 5 and 7 (2013) devices, does not prevent executable DMA mappings, which might allow local users to gain privileges via a crafted application, aka Android internal bug 28803642 and Qualcomm internal bug CR642735.
Commit Message: ARM: dma-mapping: don't allow DMA mappings to be marked executable

DMA mapping permissions were being derived from pgprot_kernel directly
without using PAGE_KERNEL.  This causes them to be marked with executable
permission, which is not what we want.  Fix this.

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>