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

[Peter Korsgaard]

>>>>> "Greg" == Greg KH <gregkh@xxxxxxxxxxxxxxxxxxx> writes:

 > On Tue, Oct 10, 2023 at 08:19:48AM +0200, Peter Korsgaard wrote:
 >> >>>>> "Greg" == Greg KH <gregkh@xxxxxxxxxxxxxxxxxxx> 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 <javier.carrasco.cruz@xxxxxxxxx>
 >> >> Reported-and-tested-by: syzbot+1f53a30781af65d2c955@xxxxxxxxxxxxxxxxxxxxxxxxx
 >> >> ---
 >> >> Changes in v2:
 >> >> - Remove unnecessary 'err == 0' case
 >> >> - Link to v1: https://lore.kernel.org/r/20231009-topic-dm9601_uninit_mdio_read-v1-1-d4d775e24e3b@xxxxxxxxx
 >> >> ---
 >> >> 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 <peter@xxxxxxxxxxxxx>

 > Great, can someone add a cc: stable@ tag for this too please?

Cc: stable@xxxxxxxxxxxxxxx

-- 
Bye, Peter Korsgaard