Commit f53a7ad1 authored Aug 24, 2019 by Prashant Malani Committed by David S. Miller Aug 25, 2019

r8152: Set memory to all 0xFFs on failed reg reads



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>

parent 71778951

drivers/net/usb/r8152.c

+4 −1

Original line number	Diff line number	Diff line
		@@ -799,8 +799,11 @@ 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);

		kfree(tmp);

		return ret;

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