[PATCH 4.20 19/50] pinctrl: sunxi: Correct number of IRQ banks on H6 main pin controller

Greg Kroah-Hartman
2019-02-13T18:47:08Z

From: Chen-Yu Tsai <wens@csie.org>

commit 10098709b4ee6f6f19f25ba81d9c6f83518c584c upstream.

The H6 main pin controller has four banks of interrupt-triggering pins.
The driver as originally submitted only specified three, but had pin
descriptions referencing a fourth bank. This results in a out-of-bounds
access into .irq_array of struct sunxi_pinctrl. This however did not
result in a crash until v4.20, with commit a66d972465d1 ("devres: Align
data[] to ARCH_KMALLOC_MINALIGN"), which changed the alignment of memory
region returned by devm_kcalloc(). The increase likely moved the
out-of-bounds access into the next, unmapped page.

With KASAN on, the bug is quite clear:

BUG: KASAN: slab-out-of-bounds in sunxi_pinctrl_init_with_variant+0x49c/0x12b8
Write of size 4 at addr ffff80002c680280 by task swapper/0/1

CPU: 2 PID: 1 Comm: swapper/0 Not tainted 5.0.0-rc1-00016-gc480a5e6a077 #3
Hardware name: OrangePi Lite2 (DT)
Call trace:
dump_backtrace+0x0/0x220
show_stack+0x14/0x20
dump_stack+0xac/0xd4
print_address_description+0x60/0x25c
kasan_report+0x14c/0x1ac
__asan_store4+0x80/0xa0
sunxi_pinctrl_init_with_variant+0x49c/0x12b8
h6_pinctrl_probe+0x18/0x20
platform_drv_probe+0x6c/0xc8
really_probe+0x244/0x4b0
driver_probe_device.part.4+0x11c/0x164
__driver_attach+0x120/0x190
bus_for_each_dev+0xe8/0x158
driver_attach+0x30/0x40
bus_add_driver+0x308/0x318
driver_register+0xbc/0x1d0
__platform_driver_register+0x7c/0x88
h6_pinctrl_driver_init+0x18/0x20
do_one_initcall+0xd4/0x208
kernel_init_freeable+0x230/0x2c8
kernel_init+0x10/0x108
ret_from_fork+0x10/0x1c

Allocated by task 1:
kasan_kmalloc.part.0+0x4c/0x100
kasan_kmalloc+0xc4/0xe8
kasan_slab_alloc+0x14/0x20
__kmalloc_track_caller+0x130/0x238
devm_kmalloc+0x34/0xd0
sunxi_pinctrl_init_with_variant+0x1d8/0x12b8
h6_pinctrl_probe+0x18/0x20
platform_drv_probe+0x6c/0xc8
really_probe+0x244/0x4b0
driver_probe_device.part.4+0x11c/0x164
__driver_attach+0x120/0x190
bus_for_each_dev+0xe8/0x158
driver_attach+0x30/0x40
bus_add_driver+0x308/0x318
driver_register+0xbc/0x1d0
__platform_driver_register+0x7c/0x88
h6_pinctrl_driver_init+0x18/0x20
do_one_initcall+0xd4/0x208
kernel_init_freeable+0x230/0x2c8
kernel_init+0x10/0x108
ret_from_fork+0x10/0x1c

Freed by task 0:
(stack is not available)

The buggy address belongs to the object at ffff80002c680080
which belongs to the cache kmalloc-512 of size 512
The buggy address is located 0 bytes to the right of
512-byte region [ffff80002c680080, ffff80002c680280)
The buggy address belongs to the page:
page:ffff7e0000b1a000 count:1 mapcount:0 mapping:ffff80002e00c780 index:0xffff80002c683c80 compound_mapcount: 0
flags: 0x10200(slab|head)
raw: 0000000000010200 ffff80002e003a10 ffff80002e003a10 ffff80002e00c780
raw: ffff80002c683c80 0000000000100001 00000001ffffffff 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
ffff80002c680180: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
ffff80002c680200: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>ffff80002c680280: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
^
ffff80002c680300: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
ffff80002c680380: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc

Correct the number of IRQ banks so there are no more mismatches.

Fixes: c8a830904991 ("pinctrl: sunxi: add support for the Allwinner H6 main pin controller")
Cc: <stable@vger.kernel.org>
Signed-off-by: Chen-Yu Tsai <wens@csie.org>
Tested-by: Neil Armstrong <narmstrong@baylibre.com>
Acked-by: Maxime Ripard <maxime.ripard@bootlin.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
drivers/pinctrl/sunxi/pinctrl-sun50i-h6.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

--- a/drivers/pinctrl/sunxi/pinctrl-sun50i-h6.c
+++ b/drivers/pinctrl/sunxi/pinctrl-sun50i-h6.c
@@ -588,7 +588,7 @@ static const unsigned int h6_irq_bank_ma
static const struct sunxi_pinctrl_desc h6_pinctrl_data = {
.pins = h6_pins,
.npins = ARRAY_SIZE(h6_pins),
- .irq_banks = 3,
+ .irq_banks = 4,
.irq_bank_map = h6_irq_bank_map,
.irq_read_needs_mux = true,
};