Subject: Re: [PATCH v2] net: usb: dm9601: fix uninitialized variable use in dm9601_mdio_read

From: Peter Korsgaard <[email-masked]>
Date: Tue, 10 Oct 2023 08:19:48 +0200

>>>>> "Greg" == Greg KH <[email-masked]> writes:

 > On Tue, Oct 10, 2023 at 12:26:14AM +0200, Javier Carrasco wrote:
 >> syzbot has found an uninit-value bug triggered by the dm9601 driver [1].
 >> 
 >> This error happens because the variable res is not updated if the call
 >> to dm_read_shared_word returns an error. In this particular case -EPROTO
 >> was returned and res stayed uninitialized.
 >> 
 >> This can be avoided by checking the return value of dm_read_shared_word
 >> and propagating the error if the read operation failed.
 >> 
 >> [1] https://syzkaller.appspot.com/bug?extid=1f53a30781af65d2c955
 >> 
 >> Signed-off-by: Javier Carrasco <[email-masked]>
 >> Reported-and-tested-by: [email-masked]
 >> ---
 >> Changes in v2:
 >> - Remove unnecessary 'err == 0' case
 >> - Link to v1: https://lore.kernel.org/r/[email-masked]
 >> ---
 >> drivers/net/usb/dm9601.c | 7 ++++++-
 >> 1 file changed, 6 insertions(+), 1 deletion(-)

 > What commit id does this fix?

It has been there since the beginning, so:

Fixes: d0374f4f9c35cdfbee0 ("USB: Davicom DM9601 usbnet driver")

Acked-by: Peter Korsgaard <[email-masked]>

-- 
Bye, Peter Korsgaard