Patchwork efi/arm64: add a terminator for ptdump marker

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Submitter Qian Cai
Date Jan. 29, 2019, 5:36 p.m.
Message ID <20190129173600.38856-1-cai@lca.pw>
Download mbox | patch
Permalink /patch/712559/
State New
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Comments

Qian Cai - Jan. 29, 2019, 5:36 p.m.
Read efi_page_tables debugfs triggering an out-of-bounds access here,

arch/arm64/mm/dump.c: 282
if (addr >= st->marker[1].start_address) {

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.

 # cat /sys/kernel/debug/efi_page_tables
---[ UEFI runtime start ]---
0x0000000020000000-0x0000000020010000          64K PTE       RW NX SHD AF NG         UXN MEM/NORMAL
0x0000000020200000-0x0000000021340000       17664K PTE       RW NX SHD AF NG         UXN MEM/NORMAL
0x0000000021340000-0x0000000021350000          64K PTE       RW x  SHD AF NG         UXN MEM/NORMAL
0x0000000021350000-0x0000000021370000         128K PTE       RW NX SHD AF NG         UXN MEM/NORMAL
0x0000000021370000-0x0000000021380000          64K PTE       RW x  SHD AF NG         UXN MEM/NORMAL
0x0000000021380000-0x00000000213b0000         192K PTE       RW NX SHD AF NG         UXN MEM/NORMAL
0x00000000213b0000-0x0000000021490000         896K PTE       RW x  SHD AF NG         UXN MEM/NORMAL
0x0000000021490000-0x00000000214b0000         128K PTE       RW NX SHD AF NG         UXN MEM/NORMAL
0x00000000214b0000-0x00000000214e0000         192K PTE       RW x  SHD AF NG         UXN MEM/NORMAL
0x00000000214e0000-0x00000000214f0000          64K PTE       RW NX SHD AF NG         UXN MEM/NORMAL
0x00000000214f0000-0x0000000021540000         320K PTE       RW x  SHD AF NG         UXN MEM/NORMAL
0x0000000021540000-0x0000000021560000         128K PTE       RW NX SHD AF NG         UXN MEM/NORMAL
0x0000000021560000-0x0000000021580000         128K PTE       RW x  SHD AF NG         UXN MEM/NORMAL
0x0000000021580000-0x00000000215a0000         128K PTE       RW NX SHD AF NG         UXN MEM/NORMAL
0x00000000215a0000-0x00000000215d0000         192K PTE       RW x  SHD AF NG         UXN MEM/NORMAL
0x00000000215d0000-0x00000000215e0000          64K PTE       RW NX SHD AF NG         UXN MEM/NORMAL
0x00000000215e0000-0x0000000021600000         128K PTE       RW x  SHD AF NG         UXN MEM/NORMAL
0x0000000021600000-0x0000000021800000           2M PTE       RW NX SHD AF NG         UXN MEM/NORMAL
0x0000000021800000-0x0000000021840000         256K PTE       RW x  SHD AF NG         UXN MEM/NORMAL
0x0000000021840000-0x00000000218e0000         640K PTE       RW NX SHD AF NG         UXN MEM/NORMAL
0x00000000218e0000-0x0000000021900000         128K PTE       RW x  SHD AF NG         UXN MEM/NORMAL
0x0000000021900000-0x0000000021920000         128K PTE       RW NX SHD AF NG         UXN MEM/NORMAL
0x0000000021920000-0x0000000021950000         192K PTE       RW x  SHD AF NG         UXN MEM/NORMAL
0x0000000021950000-0x00000000219a0000         320K PTE       RW NX SHD AF NG         UXN DEVICE/nGnRE
---[ UEFI runtime end ]---
---[ (null) ]---
---[ (null) ]---

[12126.163970] BUG: KASAN: global-out-of-bounds in note_page+0x1f0/0xac0
[12126.170404] Read of size 8 at addr ffff2000123f2ac0 by task read_all/42464
[12126.199520] Call trace:
[12126.201972]  dump_backtrace+0x0/0x298
[12126.205627]  show_stack+0x24/0x30
[12126.208944]  dump_stack+0xb0/0xdc
[12126.212258]  print_address_description+0x64/0x2b0
[12126.216954]  kasan_report+0x150/0x1a4
[12126.220610]  __asan_report_load8_noabort+0x30/0x3c
[12126.225392]  note_page+0x1f0/0xac0
[12126.228786]  walk_pgd+0xb4/0x244
[12126.232005]  ptdump_walk_pgd+0xec/0x140
[12126.235833]  ptdump_show+0x40/0x50
[12126.239237]  seq_read+0x3f8/0xad0
[12126.242548]  full_proxy_read+0x9c/0xc0
[12126.246290]  __vfs_read+0xfc/0x4c8
[12126.249684]  vfs_read+0xec/0x208
[12126.252904]  ksys_read+0xd0/0x15c
[12126.256210]  __arm64_sys_read+0x84/0x94
[12126.260048]  el0_svc_handler+0x258/0x304
[12126.263963]  el0_svc+0x8/0xc
[12126.266834]
[12126.268317] The buggy address belongs to the variable:
[12126.273458]  __compound_literal.0+0x20/0x800
[12126.277718]
[12126.279201] Memory state around the buggy address:
[12126.283987]  ffff2000123f2980: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
[12126.291200]  ffff2000123f2a00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 fa
[12126.298412] >ffff2000123f2a80: fa fa fa fa 00 00 00 00 fa fa fa fa 00 00 00 00
[12126.305624]                                            ^
[12126.310927]  ffff2000123f2b00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
[12126.318140]  ffff2000123f2b80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 0

Fixes: 9d80448ac92b ("efi/arm64: Add debugfs node to dump UEFI runtime
page tables")
Signed-off-by: Qian Cai <cai@lca.pw>
---
 drivers/firmware/efi/arm-runtime.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)
Ard Biesheuvel - Jan. 30, 2019, 1:17 p.m.
On Tue, 29 Jan 2019 at 18:36, Qian Cai <cai@lca.pw> wrote:
>
> Read efi_page_tables debugfs triggering an out-of-bounds access here,
>
> arch/arm64/mm/dump.c: 282
> if (addr >= st->marker[1].start_address) {
>
> 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.
>
>  # cat /sys/kernel/debug/efi_page_tables
> ---[ UEFI runtime start ]---
> 0x0000000020000000-0x0000000020010000          64K PTE       RW NX SHD AF NG         UXN MEM/NORMAL
> 0x0000000020200000-0x0000000021340000       17664K PTE       RW NX SHD AF NG         UXN MEM/NORMAL
> 0x0000000021340000-0x0000000021350000          64K PTE       RW x  SHD AF NG         UXN MEM/NORMAL
> 0x0000000021350000-0x0000000021370000         128K PTE       RW NX SHD AF NG         UXN MEM/NORMAL
> 0x0000000021370000-0x0000000021380000          64K PTE       RW x  SHD AF NG         UXN MEM/NORMAL
> 0x0000000021380000-0x00000000213b0000         192K PTE       RW NX SHD AF NG         UXN MEM/NORMAL
> 0x00000000213b0000-0x0000000021490000         896K PTE       RW x  SHD AF NG         UXN MEM/NORMAL
> 0x0000000021490000-0x00000000214b0000         128K PTE       RW NX SHD AF NG         UXN MEM/NORMAL
> 0x00000000214b0000-0x00000000214e0000         192K PTE       RW x  SHD AF NG         UXN MEM/NORMAL
> 0x00000000214e0000-0x00000000214f0000          64K PTE       RW NX SHD AF NG         UXN MEM/NORMAL
> 0x00000000214f0000-0x0000000021540000         320K PTE       RW x  SHD AF NG         UXN MEM/NORMAL
> 0x0000000021540000-0x0000000021560000         128K PTE       RW NX SHD AF NG         UXN MEM/NORMAL
> 0x0000000021560000-0x0000000021580000         128K PTE       RW x  SHD AF NG         UXN MEM/NORMAL
> 0x0000000021580000-0x00000000215a0000         128K PTE       RW NX SHD AF NG         UXN MEM/NORMAL
> 0x00000000215a0000-0x00000000215d0000         192K PTE       RW x  SHD AF NG         UXN MEM/NORMAL
> 0x00000000215d0000-0x00000000215e0000          64K PTE       RW NX SHD AF NG         UXN MEM/NORMAL
> 0x00000000215e0000-0x0000000021600000         128K PTE       RW x  SHD AF NG         UXN MEM/NORMAL
> 0x0000000021600000-0x0000000021800000           2M PTE       RW NX SHD AF NG         UXN MEM/NORMAL
> 0x0000000021800000-0x0000000021840000         256K PTE       RW x  SHD AF NG         UXN MEM/NORMAL
> 0x0000000021840000-0x00000000218e0000         640K PTE       RW NX SHD AF NG         UXN MEM/NORMAL
> 0x00000000218e0000-0x0000000021900000         128K PTE       RW x  SHD AF NG         UXN MEM/NORMAL
> 0x0000000021900000-0x0000000021920000         128K PTE       RW NX SHD AF NG         UXN MEM/NORMAL
> 0x0000000021920000-0x0000000021950000         192K PTE       RW x  SHD AF NG         UXN MEM/NORMAL
> 0x0000000021950000-0x00000000219a0000         320K PTE       RW NX SHD AF NG         UXN DEVICE/nGnRE
> ---[ UEFI runtime end ]---
> ---[ (null) ]---
> ---[ (null) ]---
>
> [12126.163970] BUG: KASAN: global-out-of-bounds in note_page+0x1f0/0xac0
> [12126.170404] Read of size 8 at addr ffff2000123f2ac0 by task read_all/42464
> [12126.199520] Call trace:
> [12126.201972]  dump_backtrace+0x0/0x298
> [12126.205627]  show_stack+0x24/0x30
> [12126.208944]  dump_stack+0xb0/0xdc
> [12126.212258]  print_address_description+0x64/0x2b0
> [12126.216954]  kasan_report+0x150/0x1a4
> [12126.220610]  __asan_report_load8_noabort+0x30/0x3c
> [12126.225392]  note_page+0x1f0/0xac0
> [12126.228786]  walk_pgd+0xb4/0x244
> [12126.232005]  ptdump_walk_pgd+0xec/0x140
> [12126.235833]  ptdump_show+0x40/0x50
> [12126.239237]  seq_read+0x3f8/0xad0
> [12126.242548]  full_proxy_read+0x9c/0xc0
> [12126.246290]  __vfs_read+0xfc/0x4c8
> [12126.249684]  vfs_read+0xec/0x208
> [12126.252904]  ksys_read+0xd0/0x15c
> [12126.256210]  __arm64_sys_read+0x84/0x94
> [12126.260048]  el0_svc_handler+0x258/0x304
> [12126.263963]  el0_svc+0x8/0xc
> [12126.266834]
> [12126.268317] The buggy address belongs to the variable:
> [12126.273458]  __compound_literal.0+0x20/0x800
> [12126.277718]
> [12126.279201] Memory state around the buggy address:
> [12126.283987]  ffff2000123f2980: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
> [12126.291200]  ffff2000123f2a00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 fa
> [12126.298412] >ffff2000123f2a80: fa fa fa fa 00 00 00 00 fa fa fa fa 00 00 00 00
> [12126.305624]                                            ^
> [12126.310927]  ffff2000123f2b00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
> [12126.318140]  ffff2000123f2b80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 0
>
> Fixes: 9d80448ac92b ("efi/arm64: Add debugfs node to dump UEFI runtime
> page tables")
> Signed-off-by: Qian Cai <cai@lca.pw>

Thanks Qian

I will queue this as a fix

> ---
>  drivers/firmware/efi/arm-runtime.c | 3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/firmware/efi/arm-runtime.c b/drivers/firmware/efi/arm-runtime.c
> index 23ea1ed409d1..1d28fd933297 100644
> --- a/drivers/firmware/efi/arm-runtime.c
> +++ b/drivers/firmware/efi/arm-runtime.c
> @@ -38,7 +38,8 @@ static struct ptdump_info efi_ptdump_info = {
>         .mm             = &efi_mm,
>         .markers        = (struct addr_marker[]){
>                 { 0,            "UEFI runtime start" },
> -               { DEFAULT_MAP_WINDOW_64, "UEFI runtime end" }
> +               { DEFAULT_MAP_WINDOW_64, "UEFI runtime end" },
> +               { -1,           NULL }
>         },
>         .base_addr      = 0,
>  };
> --
> 2.17.2 (Apple Git-113)
>

Patch

diff --git a/drivers/firmware/efi/arm-runtime.c b/drivers/firmware/efi/arm-runtime.c
index 23ea1ed409d1..1d28fd933297 100644
--- a/drivers/firmware/efi/arm-runtime.c
+++ b/drivers/firmware/efi/arm-runtime.c
@@ -38,7 +38,8 @@  static struct ptdump_info efi_ptdump_info = {
 	.mm		= &efi_mm,
 	.markers	= (struct addr_marker[]){
 		{ 0,		"UEFI runtime start" },
-		{ DEFAULT_MAP_WINDOW_64, "UEFI runtime end" }
+		{ DEFAULT_MAP_WINDOW_64, "UEFI runtime end" },
+		{ -1,		NULL }
 	},
 	.base_addr	= 0,
 };