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

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[ Upstream commit f53a7ad189 ]

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>
This commit is contained in:
Prashant Malani
2019-08-24 01:36:19 -07:00
committed by Greg Kroah-Hartman
parent d9f79f0ace
commit 688fdaa54a
1 changed files with 4 additions and 1 deletions
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5
drivers/net/usb/r8152.c
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@ -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;