Re: [PATCH v2] iio: health: afe4404: Fix oob read in afe4404_[read|write]_raw

[Andy Shevchenko <andriy.shevchenko@linux.intel.com>]

On Mon, Nov 07, 2022 at 02:04:25AM +0000, Wei Yongjun wrote:
> From: Wei Yongjun <weiyongjun1@huawei.com>
> 
> KASAN report out-of-bounds read as follows:
> 
> BUG: KASAN: global-out-of-bounds in afe4404_read_raw+0x2ce/0x380 [afe4404]
> Read of size 4 at addr ffffffffc00e4658 by task cat/278
> 
> CPU: 1 PID: 278 Comm: cat Tainted: G
> Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.15.0-1 04/01/2014
> Call Trace:
>  <TASK>
>  afe4404_read_raw+0x2ce/0x380 [afe4404]
>  iio_read_channel_info+0x249/0x2e0 [industrialio]
>  dev_attr_show+0x4b/0xa0 drivers/base/core.c:2195
>  sysfs_kf_seq_show+0x1ec/0x390 fs/sysfs/file.c:59
>  seq_read_iter+0x48d/0x10b0 fs/seq_file.c:230
>  kernfs_fop_read_iter+0x4e6/0x710 fs/kernfs/file.c:275
>  call_read_iter include/linux/fs.h:2153 [inline]
>  new_sync_read fs/read_write.c:389 [inline]
>  vfs_read+0x5f2/0x890 fs/read_write.c:470
>  ksys_read+0x106/0x220 fs/read_write.c:613
>  do_syscall_x64 arch/x86/entry/common.c:50 [inline]
>  do_syscall_64+0x38/0xa0 arch/x86/entry/common.c:80
>  entry_SYSCALL_64_after_hwframe+0x72/0xdc
> RIP: 0033:0x7fe9c5ef6992
>  </TASK>

Read this
https://www.kernel.org/doc/html/latest/process/submitting-patches.html#backtraces-in-commit-messages
and update your commit message accordingly.

> The buggy address belongs to the variable:
>  afe4404_channel_leds+0x18/0xffffffffffffe9c0 [afe4404]
> 
> This issue can be reproduce by singe command:
> 
>  $ cat /sys/bus/i2c/devices/0-0058/iio\:device0/in_intensity6_raw
> 
> The array size of afe4404_channel_leds and afe4404_channel_offdacs
> are less than channels, so access with chan->address cause OOB read
> in afe4404_[read|write]_raw. Fix it by moving access before use them.

-- 
With Best Regards,
Andy Shevchenko