Re: [PATCH 5.15.y] ALSA: usb-audio: Fix a DMA to stack memory bug

[Greg KH <gregkh@linuxfoundation.org>]

On Tue, Dec 17, 2024 at 12:43:18PM +0000, Benoît Sevens wrote:
> From: Dan Carpenter <dan.carpenter@linaro.org>
> 
> The usb_get_descriptor() function does DMA so we're not allowed
> to use a stack buffer for that.  Doing DMA to the stack is not portable
> all architectures.  Move the "new_device_descriptor" from being stored
> on the stack and allocate it with kmalloc() instead.
> 
> Fixes: b909df18ce2a ("ALSA: usb-audio: Fix potential out-of-bound accesses for Extigy and Mbox devices")
> Cc: stable@kernel.org
> Signed-off-by: Dan Carpenter <dan.carpenter@linaro.org>
> Link: https://patch.msgid.link/60e3aa09-039d-46d2-934c-6f123026c2eb@stanley.mountain
> Signed-off-by: Takashi Iwai <tiwai@suse.de>
> (cherry picked from commit f7d306b47a24367302bd4fe846854e07752ffcd9)
> [Benoît: there is no mbox3 suppport and no __free macro in 5.15]
> Signed-off-by: Benoît Sevens <bsevens@google.com>
> ---
>  sound/usb/quirks.c | 31 +++++++++++++++++++++----------
>  1 file changed, 21 insertions(+), 10 deletions(-)

I see 2 versions of this, which one is correct?

When sending new versions, always properly version them.  I'll delete
this and wait for a proper v2.

thanks,

greg k-h