Re: [PATCH ethtool] ethtool: Fix uninitialized variable use at qsfp dump

[Andrew Lunn <andrew@lunn.ch>]

On Thu, Sep 27, 2018 at 04:48:35PM +0300, Eran Ben Elisha wrote:
> Struct sff_diags can be used uninitialized at sff8636_show_dom, this
> caused the tool to show unreported fields (supports_alarms) by the lower
> level driver.
> 
> Fixes: a5e73bb05ee4 ("ethtool:QSFP Plus/QSFP28 Diagnostics Information Support")
> Signed-off-by: Eran Ben Elisha <eranbe@mellanox.com>
> ---
>  qsfp.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/qsfp.c b/qsfp.c
> index 32e195d12dc0..d196aa1753de 100644
> --- a/qsfp.c
> +++ b/qsfp.c
> @@ -671,7 +671,7 @@ static void sff8636_dom_parse(const __u8 *id, struct sff_diags *sd)
>  
>  static void sff8636_show_dom(const __u8 *id, __u32 eeprom_len)
>  {
> -	struct sff_diags sd;
> +	struct sff_diags sd = {0};
>  	char *rx_power_string = NULL;
>  	char power_string[MAX_DESC_SIZE];
>  	int i;

Hi Erin

I wonder if similar bugs happen in sfpdiag.c?

void sff8472_show_all(const __u8 *id)
{
        struct sff_diags sd;
        char *rx_power_string = NULL;
        int i;

sd is also on the stack and not initialised. Could you expand your
patch to also clear this one as well, just to be safe.

Thanks
	Andrew