On 16/09/20 11:52 am, Greg KH wrote: > 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. This looks viable to me. I'll be sure to try this out. >> 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. Noted. Thank you for your time. Thanks, Anant
