[PATCH] arm64: dump: hide kernel pointers
From: Miles Chen
Date: Tue Feb 28 2017 - 02:19:00 EST
Mask kernel pointers of /sys/kernel/debug/kernel_page_tables entry like
/proc/vmallocinfo does.
With sysctl kernel.kptr_restrict=0 or 1:
cat /sys/kernel/debug/kernel_page_tables
---[ Modules start ]---
---[ Modules end ]---
---[ vmalloc() Area ]---
ffffff8008000000-ffffff8008010000 64K PTE RW NX SHD AF...
ffffff8008015000-ffffff8008016000 4K PTE RW NX SHD AF...
ffffff8008020000-ffffff8008030000 64K PTE RW NX SHD AF...
ffffff8008031000-ffffff8008071000 256K PTE RW NX SHD AF...
ffffff8008080000-ffffff8008200000 1536K PTE ro x SHD AF...
ffffff8008200000-ffffff8008400000 2M PMD ro x SHD AF...
ffffff8008400000-ffffff8008540000 1280K PTE ro x SHD AF...
ffffff8008540000-ffffff8008690000 1344K PTE ro NX SHD AF...
ffffff8008940000-ffffff8008a10000 832K PTE RW NX SHD AF...
ffffff8008aca000-ffffff8008acd000 12K PTE RW NX SHD AF...
ffffffbebffd8000-ffffffbebffdb000 12K PTE RW NX SHD AF...
---[ vmalloc() End ]---
---[ Fixmap start ]---
ffffffbefe800000-ffffffbefea00000 2M PMD ro NX SHD AF...
---[ Fixmap end ]---
---[ PCI I/O start ]---
---[ PCI I/O end ]---
---[ Linear Mapping ]---
ffffffc000000000-ffffffc000080000 512K PTE RW NX SHD AF...
ffffffc000080000-ffffffc000200000 1536K PTE ro NX SHD AF...
ffffffc000200000-ffffffc000600000 4M PMD ro NX SHD AF...
ffffffc000600000-ffffffc000690000 576K PTE ro NX SHD AF...
ffffffc000690000-ffffffc000800000 1472K PTE RW NX SHD AF...
ffffffc000800000-ffffffc002000000 24M PMD RW NX SHD AF...
ffffffc002000000-ffffffc040000000 992M PMD RW NX SHD AF...
ffffffc040000000-ffffffc080000000 1G PGD RW NX SHD AF...
With sysctl kernel.kptr_restrict=2:
cat /sys/kernel/debug/kernel_page_tables
---[ Modules start ]---
---[ Modules end ]---
---[ vmalloc() Area ]---
0000000000000000-0000000000000000 64K PTE RW NX SHD AF...
0000000000000000-0000000000000000 4K PTE RW NX SHD AF...
0000000000000000-0000000000000000 64K PTE RW NX SHD AF...
0000000000000000-0000000000000000 256K PTE RW NX SHD AF...
0000000000000000-0000000000000000 1536K PTE ro x SHD AF...
0000000000000000-0000000000000000 2M PMD ro x SHD AF...
0000000000000000-0000000000000000 1280K PTE ro x SHD AF...
0000000000000000-0000000000000000 1344K PTE ro NX SHD AF...
0000000000000000-0000000000000000 832K PTE RW NX SHD AF...
0000000000000000-0000000000000000 12K PTE RW NX SHD AF...
0000000000000000-0000000000000000 12K PTE RW NX SHD AF...
---[ vmalloc() End ]---
---[ Fixmap start ]---
0000000000000000-0000000000000000 2M PMD ro NX SHD AF...
---[ Fixmap end ]---
---[ PCI I/O start ]---
---[ PCI I/O end ]---
---[ Linear Mapping ]---
0000000000000000-0000000000000000 512K PTE RW NX SHD AF...
0000000000000000-0000000000000000 1536K PTE ro NX SHD AF...
0000000000000000-0000000000000000 4M PMD ro NX SHD AF...
0000000000000000-0000000000000000 576K PTE ro NX SHD AF...
0000000000000000-0000000000000000 1472K PTE RW NX SHD AF...
0000000000000000-0000000000000000 24M PMD RW NX SHD AF...
0000000000000000-0000000000000000 992M PMD RW NX SHD AF...
0000000000000000-0000000000000000 1G PGD RW NX SHD AF...
Signed-off-by: Miles Chen <miles.chen@xxxxxxxxxxxx>
---
arch/arm64/mm/dump.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/arch/arm64/mm/dump.c b/arch/arm64/mm/dump.c
index ca74a2a..e055ecf 100644
--- a/arch/arm64/mm/dump.c
+++ b/arch/arm64/mm/dump.c
@@ -253,8 +253,8 @@ static void note_page(struct pg_state *st, unsigned long addr, unsigned level,
if (st->current_prot) {
note_prot_uxn(st, addr);
note_prot_wx(st, addr);
- pt_dump_seq_printf(st->seq, "0x%016lx-0x%016lx ",
- st->start_address, addr);
+ pt_dump_seq_printf(st->seq, "%pK-%pK ",
+ (void *)st->start_address, (void *)addr);
delta = (addr - st->start_address) >> 10;
while (!(delta & 1023) && unit[1]) {
--
1.9.1