From: Prashant Malani pmalani@chromium.org
[ Upstream commit f53a7ad189594a112167efaf17ea8d0242b5ac00 ]
get_registers() blindly copies the memory written to by the usb_control_msg() call even if the underlying urb failed.
This could lead to junk register values being read by the driver, since some indirect callers of get_registers() ignore the return values. One example is: ocp_read_dword() ignores the return value of generic_ocp_read(), which calls get_registers().
So, emulate PCI "Master Abort" behavior by setting the buffer to all 0xFFs when usb_control_msg() fails.
This patch is copied from the r8152 driver (v2.12.0) published by Realtek (www.realtek.com).
Signed-off-by: Prashant Malani pmalani@chromium.org Acked-by: Hayes Wang hayeswang@realtek.com Signed-off-by: David S. Miller davem@davemloft.net Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/net/usb/r8152.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-)
diff --git a/drivers/net/usb/r8152.c b/drivers/net/usb/r8152.c index 1a7b7bd412f9d..f2553dff5b178 100644 --- a/drivers/net/usb/r8152.c +++ b/drivers/net/usb/r8152.c @@ -787,8 +787,11 @@ int get_registers(struct r8152 *tp, u16 value, u16 index, u16 size, void *data) ret = usb_control_msg(tp->udev, usb_rcvctrlpipe(tp->udev, 0), RTL8152_REQ_GET_REGS, RTL8152_REQT_READ, value, index, tmp, size, 500); + if (ret < 0) + memset(data, 0xff, size); + else + memcpy(data, tmp, size);
- memcpy(data, tmp, size); kfree(tmp);
return ret;