On Wed, Sep 16, 2020 at 10:35:40AM +0530, Anant Thazhemadam wrote: > get_registers() copies whatever memory is written by the > usb_control_msg() call even if the underlying urb call ends up failing. > > If get_registers() fails, or ends up reading 0 bytes, meaningless and > junk register values would end up being copied over (and eventually read > by the driver), and since most of the callers of get_registers() don't > check the return values of get_registers() either, this would go unnoticed. > > It might be a better idea to try and mirror the PCI master abort > termination and set memory to 0xFFs instead in such cases. It would be better to use this new api call instead of usb_control_msg(): https://lore.kernel.org/r/20200914153756.3412156-1-gregkh@xxxxxxxxxxxxxxxxxxx How about porting this patch to run on top of that series instead? That should make this logic much simpler. > > Fixes: https://syzkaller.appspot.com/bug?extid=abbc768b560c84d92fd3 > Reported-by: syzbot+abbc768b560c84d92fd3@xxxxxxxxxxxxxxxxxxxxxxxxx > Tested-by: syzbot+abbc768b560c84d92fd3@xxxxxxxxxxxxxxxxxxxxxxxxx > Signed-off-by: Anant Thazhemadam <anant.thazhemadam@xxxxxxxxx> > --- > drivers/net/usb/rtl8150.c | 9 +++++++-- > 1 file changed, 7 insertions(+), 2 deletions(-) > > diff --git a/drivers/net/usb/rtl8150.c b/drivers/net/usb/rtl8150.c > index 733f120c852b..04fca7bfcbcb 100644 > --- a/drivers/net/usb/rtl8150.c > +++ b/drivers/net/usb/rtl8150.c > @@ -162,8 +162,13 @@ static int get_registers(rtl8150_t * dev, u16 indx, u16 size, void *data) > ret = usb_control_msg(dev->udev, usb_rcvctrlpipe(dev->udev, 0), > RTL8150_REQ_GET_REGS, RTL8150_REQT_READ, > indx, 0, buf, size, 500); > - if (ret > 0 && ret <= size) > + > + if (ret < 0) > + memset(data, 0xff, size); > + > + else > memcpy(data, buf, ret); > + > kfree(buf); > return ret; > } > @@ -276,7 +281,7 @@ static int write_mii_word(rtl8150_t * dev, u8 phy, __u8 indx, u16 reg) > > static inline void set_ethernet_addr(rtl8150_t * dev) > { > - u8 node_id[6]; > + u8 node_id[6] = {0}; This should not be needed to be done. thanks, greg k-h
