From 51635ad282ead58b9d164f07e1fb62a9456b427c Mon Sep 17 00:00:00 2001 From: Lennert Buytenhek Date: Sat, 16 Sep 2006 10:50:22 +0100 Subject: [PATCH] [ARM] 3813/1: prevent >= 4G /dev/mem mmap() Prevent userland from mapping in physical address regions >= 4G by checking for that in valid_mmap_phys_addr_range(). Unfortunately, we cannot override valid_mmap_phys_addr_range() without also overriding valid_phys_addr_range(), so copy drivers/char/mem.c's version of valid_phys_addr_range() over to arch/arm/mm/mmap.c as well. Signed-off-by: Lennert Buytenhek Signed-off-by: Russell King --- arch/arm/mm/mmap.c | 22 ++++++++++++++++++++++ include/asm-arm/io.h | 4 ++++ 2 files changed, 26 insertions(+) diff --git a/arch/arm/mm/mmap.c b/arch/arm/mm/mmap.c index 29e54807c5..b0b5f46940 100644 --- a/arch/arm/mm/mmap.c +++ b/arch/arm/mm/mmap.c @@ -114,3 +114,25 @@ full_search: } } + +/* + * You really shouldn't be using read() or write() on /dev/mem. This + * might go away in the future. + */ +int valid_phys_addr_range(unsigned long addr, size_t size) +{ + if (addr + size > __pa(high_memory)) + return 0; + + return 1; +} + +/* + * We don't use supersection mappings for mmap() on /dev/mem, which + * means that we can't map the memory area above the 4G barrier into + * userspace. + */ +int valid_mmap_phys_addr_range(unsigned long pfn, size_t size) +{ + return !(pfn + (size >> PAGE_SHIFT) > 0x00100000); +} diff --git a/include/asm-arm/io.h b/include/asm-arm/io.h index bf7b9dea30..8076a85c36 100644 --- a/include/asm-arm/io.h +++ b/include/asm-arm/io.h @@ -280,6 +280,10 @@ extern void pci_iounmap(struct pci_dev *dev, void __iomem *addr); #define BIOVEC_MERGEABLE(vec1, vec2) \ ((bvec_to_phys((vec1)) + (vec1)->bv_len) == bvec_to_phys((vec2))) +#define ARCH_HAS_VALID_PHYS_ADDR_RANGE +extern int valid_phys_addr_range(unsigned long addr, size_t size); +extern int valid_mmap_phys_addr_range(unsigned long pfn, size_t size); + /* * Convert a physical pointer to a virtual kernel pointer for /dev/mem * access -- 2.39.5