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. 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}; get_registers(dev, IDR, sizeof(node_id), node_id); memcpy(dev->netdev->dev_addr, node_id, sizeof(node_id)); -- 2.25.1
