[PATCH V2 0/2] Prevent possible PTE corruption with /dev/mem mmap

[Frantisek Hrbata]

Thanks to Dave Hansen for pointing out problems related to the pfn check in the
first version. I tried to fix it by adding a new arch_pfn_possible helper to
arch/x86/mm/physaddr.h. Please note that I'm not quite sure about the name and
the location(physaddr.h). Maybe we can keep the check directly in the
valid_mmap_phys_addr_range. I will leave this to a discussion and fix it if
required.

Question: Do we need the CONFIG_PHYS_ADDR_T_64BIT ifdef? The
boot_cpu_data.x86_phys_bits is set for all x86. So at this point it seems to me
more like an "optimization" for x86_32 or something kept from historic
reasons. I'm just curious and I of course may be missing something.

Many thanks

Frantisek Hrbata (2):
  x86: add arch_pfn_possible helper
  x86: add phys addr validity check for /dev/mem mmap

 arch/x86/include/asm/io.h |  4 ++++
 arch/x86/mm/mmap.c        | 12 ++++++++++++
 arch/x86/mm/physaddr.h    |  9 +++++++--
 3 files changed, 23 insertions(+), 2 deletions(-)

-- 
1.9.3

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