[PATCH] lan78xx: Correctly indicate invalid OTP

[PATCH] lan78xx: Correctly indicate invalid OTP

[Phil Elwell]

lan78xx_read_otp tries to return -EINVAL in the event of invalid OTP
content, but the value gets overwritten before it is returned and the
read goes ahead anyway. Make the read conditional as it should be
and preserve the error code.

Signed-off-by: Phil Elwell <phil@raspberrypi.org>
---
 drivers/net/usb/lan78xx.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/net/usb/lan78xx.c b/drivers/net/usb/lan78xx.c
index 55a78eb..32cf217 100644
--- a/drivers/net/usb/lan78xx.c
+++ b/drivers/net/usb/lan78xx.c
@@ -928,7 +928,8 @@ static int lan78xx_read_otp(struct lan78xx_net *dev, u32 offset,
 			offset += 0x100;
 		else
 			ret = -EINVAL;
-		ret = lan78xx_read_raw_otp(dev, offset, length, data);
+		if (!ret)
+			ret = lan78xx_read_raw_otp(dev, offset, length, data);
 	}
 
 	return ret;
-- 
2.7.4

Re: [PATCH] lan78xx: Correctly indicate invalid OTP

[Andrew Lunn]

On Wed, Apr 11, 2018 at 10:59:17AM +0100, Phil Elwell wrote:
> lan78xx_read_otp tries to return -EINVAL in the event of invalid OTP
> content, but the value gets overwritten before it is returned and the
> read goes ahead anyway. Make the read conditional as it should be
> and preserve the error code.

Hi Phil

Do you know that the Fixes: tag should be for this? When did it break?

Thanks
	Andrew

Re: [PATCH] lan78xx: Correctly indicate invalid OTP

[Phil Elwell]

Hi Andrew.

On 11/04/2018 13:57, Andrew Lunn wrote:
> On Wed, Apr 11, 2018 at 10:59:17AM +0100, Phil Elwell wrote:
>> lan78xx_read_otp tries to return -EINVAL in the event of invalid OTP
>> content, but the value gets overwritten before it is returned and the
>> read goes ahead anyway. Make the read conditional as it should be
>> and preserve the error code.
> 
> Hi Phil
> 
> Do you know that the Fixes: tag should be for this? When did it break?

It's been broken since day 1, so:

Fixes: 55d7de9de6c3 ("Microchip's LAN7800 family USB 2/3 to 10/100/1000 Ethernet device driver")

Re: [PATCH] lan78xx: Correctly indicate invalid OTP

[David Miller]

From: Phil Elwell <phil@raspberrypi.org>
Date: Wed, 11 Apr 2018 10:59:17 +0100

> lan78xx_read_otp tries to return -EINVAL in the event of invalid OTP
> content, but the value gets overwritten before it is returned and the
> read goes ahead anyway. Make the read conditional as it should be
> and preserve the error code.
> 
> Signed-off-by: Phil Elwell <phil@raspberrypi.org>

Applied with appropriate Fixes: tag added, and queud up for -stable.

Thanks.