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Message-Id: <20190919214810.052809203@linuxfoundation.org>
Date: Fri, 20 Sep 2019 00:04:07 +0200
From: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To: linux-kernel@...r.kernel.org
Cc: Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
stable@...r.kernel.org, Prashant Malani <pmalani@...omium.org>,
Hayes Wang <hayeswang@...ltek.com>,
"David S. Miller" <davem@...emloft.net>,
Sasha Levin <sashal@...nel.org>
Subject: [PATCH 4.9 54/74] r8152: Set memory to all 0xFFs on failed reg reads
From: Prashant Malani <pmalani@...omium.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@...omium.org>
Acked-by: Hayes Wang <hayeswang@...ltek.com>
Signed-off-by: David S. Miller <davem@...emloft.net>
Signed-off-by: Sasha Levin <sashal@...nel.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 02e29562d254e..15dc70c118579 100644
--- a/drivers/net/usb/r8152.c
+++ b/drivers/net/usb/r8152.c
@@ -689,8 +689,11 @@ 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;
--
2.20.1
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