Re: [PATCH] ALSA: control: Fix an out-of-bounds bug in get_ctl_id_hash()

On Wed, 24 Aug 2022 10:16:54 +0200, Zheyu Ma wrote:

Since the user can control the arguments provided to the kernel by the ioctl() system call, an out-of-bounds bug occurs when the 'id->name' provided by the user does not end with '\0'.

The following log can reveal it:

[ 10.002313] BUG: KASAN: stack-out-of-bounds in snd_ctl_find_id+0x36c/0x3a0 [ 10.002895] Read of size 1 at addr ffff888109f5fe28 by task snd/439 [ 10.004934] Call Trace: [ 10.007140] snd_ctl_find_id+0x36c/0x3a0 [ 10.007489] snd_ctl_ioctl+0x6cf/0x10e0

Fix this by checking the bound of 'id->name' in the loop.

Fixes: c27e1efb61c5 ("ALSA: control: Use xarray for faster lookups") Signed-off-by: Zheyu Ma zheyuma97@gmail.com

Thanks, applied now.

Takashi