From 51635ad282ead58b9d164f07e1fb62a9456b427c Mon Sep 17 00:00:00 2001 From: Lennert Buytenhek Date: Sat, 16 Sep 2006 10:50:22 +0100 Subject: [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 ++++++++++++++++++++++ 1 file changed, 22 insertions(+) (limited to 'arch/arm/mm/mmap.c') diff --git a/arch/arm/mm/mmap.c b/arch/arm/mm/mmap.c index 29e54807c5bc..b0b5f4694070 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); +} -- cgit