Messages in this thread | | | From | Peter Korsgaard <> | Subject | Re: [PATCH] net: usb: dm9601: fix uninitialized variable use in dm9601_mdio_read | Date | Mon, 09 Oct 2023 22:48:30 +0200 |
| |
>>>>> "Javier" == Javier Carrasco <javier.carrasco.cruz@gmail.com> writes:
> 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 or if no data is read (see > __usbnet_read_cmd()). 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 returning an error if the read operation failed or no data was read.
> [1] https://syzkaller.appspot.com/bug?extid=1f53a30781af65d2c955
> Signed-off-by: Javier Carrasco <javier.carrasco.cruz@gmail.com> > Reported-and-tested-by: syzbot+1f53a30781af65d2c955@syzkaller.appspotmail.com > --- > drivers/net/usb/dm9601.c | 9 ++++++++- > 1 file changed, 8 insertions(+), 1 deletion(-)
> diff --git a/drivers/net/usb/dm9601.c b/drivers/net/usb/dm9601.c > index 48d7d278631e..e223daa93229 100644 > --- a/drivers/net/usb/dm9601.c > +++ b/drivers/net/usb/dm9601.c > @@ -222,13 +222,20 @@ static int dm9601_mdio_read(struct net_device *netdev, int phy_id, int loc) > struct usbnet *dev = netdev_priv(netdev);
> __le16 res; > + int err;
> if (phy_id) { > netdev_dbg(dev->net, "Only internal phy supported\n"); > return 0; > }
> - dm_read_shared_word(dev, 1, loc, &res); > + err = dm_read_shared_word(dev, 1, loc, &res); > + if (err <= 0) { > + if (err == 0) > + err = -ENODATA;
Looking at dm_read(), it doesn't look like we can end up here with err == 0, but OK.
Acked-by: Peter Korsgaard <peter@korsgaard.com>
-- Bye, Peter Korsgaard
| |