From 688fdaa54a3e985d83de83bdf98433b5ae2e358f Mon Sep 17 00:00:00 2001 From: Prashant Malani <pmalani@chromium.org> Date: Sat, 24 Aug 2019 01:36:19 -0700 Subject: [PATCH] r8152: Set memory to all 0xFFs on failed reg reads [ 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 f1b5201cc3207..a065a6184f7e4 100644 --- a/drivers/net/usb/r8152.c +++ b/drivers/net/usb/r8152.c @@ -788,8 +788,11 @@ 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; -- GitLab