Qian Cai
74c953ca5f
efi/arm64: Fix debugfs crash by adding a terminator for ptdump marker
When reading 'efi_page_tables' debugfs triggers an out-of-bounds access here:
arch/arm64/mm/dump.c: 282
if (addr >= st->marker[1].start_address) {
called from:
arch/arm64/mm/dump.c: 331
note_page(st, addr, 2, pud_val(pud));
because st->marker++ is is called after "UEFI runtime end" which is the
last element in addr_marker[]. Therefore, add a terminator like the one
for kernel_page_tables, so it can be skipped to print out non-existent
markers.
Here's the KASAN bug report:
# cat /sys/kernel/debug/efi_page_tables
---[ UEFI runtime start ]---
0x0000000020000000-0x0000000020010000 64K PTE RW NX SHD AF ...
0x0000000020200000-0x0000000021340000 17664K PTE RW NX SHD AF ...
...
0x0000000021920000-0x0000000021950000 192K PTE RW x SHD AF ...
0x0000000021950000-0x00000000219a0000 320K PTE RW NX SHD AF ...
---[ UEFI runtime end ]---
---[ (null) ]---
---[ (null) ]---
BUG: KASAN: global-out-of-bounds in note_page+0x1f0/0xac0
Read of size 8 at addr ffff2000123f2ac0 by task read_all/42464
Call trace:
dump_backtrace+0x0/0x298
show_stack+0x24/0x30
dump_stack+0xb0/0xdc
print_address_description+0x64/0x2b0
kasan_report+0x150/0x1a4
__asan_report_load8_noabort+0x30/0x3c
note_page+0x1f0/0xac0
walk_pgd+0xb4/0x244
ptdump_walk_pgd+0xec/0x140
ptdump_show+0x40/0x50
seq_read+0x3f8/0xad0
full_proxy_read+0x9c/0xc0
__vfs_read+0xfc/0x4c8
vfs_read+0xec/0x208
ksys_read+0xd0/0x15c
__arm64_sys_read+0x84/0x94
el0_svc_handler+0x258/0x304
el0_svc+0x8/0xc
The buggy address belongs to the variable:
__compound_literal.0+0x20/0x800
Memory state around the buggy address:
ffff2000123f2980: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
ffff2000123f2a00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 fa
>ffff2000123f2a80: fa fa fa fa 00 00 00 00 fa fa fa fa 00 00 00 00
^
ffff2000123f2b00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
ffff2000123f2b80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 0
[ ardb: fix up whitespace ]
[ mingo: fix up some moar ]
Signed-off-by: Qian Cai <cai@lca.pw>
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-efi@vger.kernel.org
Fixes: 9d80448ac9
("efi/arm64: Add debugfs node to dump UEFI runtime page tables")
Link: http://lkml.kernel.org/r/20190202095017.13799-2-ard.biesheuvel@linaro.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2019-02-02 11:27:29 +01:00
..
2018-12-26 13:38:38 -08:00
2019-01-03 18:57:57 -08:00
2018-10-31 08:54:16 -07:00
2018-11-15 10:04:46 +01:00
2019-02-02 11:27:29 +01:00
2018-05-14 08:57:49 +02:00
2018-06-12 16:19:22 -07:00
2018-05-14 08:57:47 +02:00
2018-05-14 08:57:48 +02:00
2018-07-22 14:13:43 +02:00
2016-11-13 08:23:15 +01:00
2018-07-03 17:43:10 +02:00
2018-12-03 17:11:02 -08:00
2018-11-30 09:37:57 +01:00
2016-06-27 13:06:54 +02:00
2018-11-01 13:02:21 +01:00
2018-07-17 09:15:05 +02:00
2017-01-07 08:58:07 +01:00
2018-09-12 16:41:41 +02:00
2018-05-14 08:57:47 +02:00
2017-02-01 08:45:44 +01:00
2018-11-15 10:04:46 +01:00
2017-11-02 11:10:55 +01:00
2018-06-12 16:19:22 -07:00
2018-11-15 10:04:45 +01:00
2018-01-08 12:58:35 +02:00
2018-11-30 09:06:32 +01:00