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linux/arch/x86/mm
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Kees Cook a4866aa812 mm: Tighten x86 /dev/mem with zeroing reads 
Under CONFIG_STRICT_DEVMEM, reading System RAM through /dev/mem is
disallowed. However, on x86, the first 1MB was always allowed for BIOS
and similar things, regardless of it actually being System RAM. It was
possible for heap to end up getting allocated in low 1MB RAM, and then
read by things like x86info or dd, which would trip hardened usercopy:

usercopy: kernel memory exposure attempt detected from ffff880000090000 (dma-kmalloc-256) (4096 bytes)

This changes the x86 exception for the low 1MB by reading back zeros for
System RAM areas instead of blindly allowing them. More work is needed to
extend this to mmap, but currently mmap doesn't go through usercopy, so
hardened usercopy won't Oops the kernel.

Reported-by: Tommi Rantala <tommi.t.rantala@nokia.com>
Tested-by: Tommi Rantala <tommi.t.rantala@nokia.com>
Signed-off-by: Kees Cook <keescook@chromium.org>
2017-04-12 11:40:23 -07:00
..
kmemcheck x86/mm: Audit and remove any unnecessary uses of module.h 2016-07-14 13:04:20 +02:00
amdtopology.c x86/mm/numa: Open code function early_get_boot_cpu_id() 2016-08-15 08:51:54 +02:00
debug_pagetables.c x86/mm/ptdump: Make (debugfs)/kernel_page_tables read-only 2015-12-04 12:55:01 +01:00
dump_pagetables.c x86/mm/ptdump: Add address marker for KASAN shadow region 2017-02-16 19:53:25 +01:00
extable.c sched/headers: Prepare for new header dependencies before moving code to <linux/sched/debug.h> 2017-03-02 08:42:34 +01:00
fault.c sched/headers: Prepare for new header dependencies before moving code to <linux/sched/task_stack.h> 2017-03-02 08:42:36 +01:00
gup.c x86, mm: unify exit paths in gup_pte_range() 2017-03-09 17:01:09 -08:00
highmem_32.c x86/mm: Audit and remove any unnecessary uses of module.h 2016-07-14 13:04:20 +02:00
hugetlbpage.c sched/headers: Prepare for new header dependencies before moving more code to <linux/sched/mm.h> 2017-03-02 08:42:30 +01:00
ident_map.c x86/power/64: Always create temporary identity mapping correctly 2016-08-08 22:04:30 +02:00
init_32.c mm: add arch-independent testcases for RODATA 2017-02-27 18:43:48 -08:00
init_64.c mm: add arch-independent testcases for RODATA 2017-02-27 18:43:48 -08:00
init.c mm: Tighten x86 /dev/mem with zeroing reads 2017-04-12 11:40:23 -07:00
iomap_32.c x86/mm: Audit and remove any unnecessary uses of module.h 2016-07-14 13:04:20 +02:00
ioremap.c x86/mm: Audit and remove any unnecessary uses of module.h 2016-07-14 13:04:20 +02:00
kasan_init_64.c x86/kasan: Fix boot with KASAN=y and PROFILE_ANNOTATED_BRANCHES=y 2017-03-14 00:00:55 +01:00
kaslr.c x86/mm/KASLR: Exclude EFI region from KASLR VA space randomization 2017-03-24 09:04:27 +01:00
kmmio.c x86/mm: Audit and remove any unnecessary uses of module.h 2016-07-14 13:04:20 +02:00
Makefile x86/mm: Implement ASLR for kernel memory regions 2016-07-08 17:33:46 +02:00
mm_internal.h
mmap.c sched/headers: Prepare for new header dependencies before moving more code to <linux/sched/mm.h> 2017-03-02 08:42:30 +01:00
mmio-mod.c x86/mm: Audit and remove any unnecessary uses of module.h 2016-07-14 13:04:20 +02:00
mpx.c x86/mpx: Make unnecessarily global function static 2017-03-16 09:17:05 +01:00
numa_32.c x86/mm: Audit and remove any unnecessary uses of module.h 2016-07-14 13:04:20 +02:00
numa_64.c
numa_emulation.c
numa_internal.h
numa.c ACPI/NUMA: Do not map pxm to node when NUMA is turned off 2016-12-15 11:32:32 +01:00
pageattr-test.c x86/mm/pat: Make mm/pageattr[-test].c explicitly non-modular 2015-08-25 09:48:38 +02:00
pageattr.c x86/mm/cpa: Avoid wbinvd() for PREEMPT 2017-01-30 15:33:52 +01:00
pat_internal.h x86/mm/pat: Convert to pr_*() usage 2015-05-27 14:40:59 +02:00
pat_rbtree.c x86/mm/pat: Use rb_entry() 2017-02-04 17:18:00 +01:00
pat.c x86/pat, mm: Make track_pfn_insert() return void 2016-11-09 21:36:07 +01:00
pf_in.c x86/mm: Audit and remove any unnecessary uses of module.h 2016-07-14 13:04:20 +02:00
pf_in.h
pgtable_32.c Merge branch 'x86-headers-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2016-08-01 14:23:42 -04:00
pgtable.c mm, x86: add support for PUD-sized transparent hugepages 2017-02-24 17:46:54 -08:00
physaddr.c x86/mm: Audit and remove any unnecessary uses of module.h 2016-07-14 13:04:20 +02:00
physaddr.h
pkeys.c x86/fpu: Finish excising 'eagerfpu' 2016-10-18 09:56:03 +02:00
setup_nx.c Revert "x86/mm/32: Set NX in __supported_pte_mask before enabling paging" 2016-04-26 19:52:57 +02:00
srat.c Merge branch 'x86-headers-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2016-08-01 14:23:42 -04:00
testmmiotrace.c
tlb.c x86/mm/64: Enable vmapped stacks (CONFIG_HAVE_ARCH_VMAP_STACK=y) 2016-08-24 12:11:42 +02:00