On Tue, Jan 15, 2019 at 10:45:43AM +0800, Chen-Yu Tsai wrote:
> 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@xxxxxxxxxxxxxxx>
> Signed-off-by: Chen-Yu Tsai <wens@xxxxxxxx>
Acked-by: Maxime Ripard <maxime.ripard@xxxxxxxxxxx>
Thanks!
Maxime
--
Maxime Ripard, Bootlin
Embedded Linux and Kernel engineering
https://bootlin.com
