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

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

[Eran Ben Elisha]

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;
-- 
1.8.3.1

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

[Andrew Lunn]

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

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

[Eran Ben Elisha]

On 9/27/2018 7:08 PM, Andrew Lunn wrote:
> 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?

Bug is not present here, all sd needed fields are being filled in 
sff8472_parse_eeprom right at the beginning.

> 
> 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.

Although bug is not present, I agree that better initialize it to be on 
the safe side. will post soon.

Eran

> 
> Thanks
> 	Andrew
>