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 <pmal...@chromium.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 0cc03a9ff545..eee0f5007ee3 100644
--- a/drivers/net/usb/r8152.c
+++ b/drivers/net/usb/r8152.c
@@ -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);
- memcpy(data, tmp, size);
kfree(tmp);
return ret;
--
2.23.0.187.g17f5b7556c-goog
