Re: xen-analysis ECLAIR support

[Jan Beulich <jbeulich@xxxxxxxx>]

On 25.08.2023 10:18, Michal Orzel wrote:
> Hi Stefano,
> 
> On 25/08/2023 00:24, Stefano Stabellini wrote:
>>
>>
>> Hi Luca,
>>
>> We are looking into adding ECLAIR support for xen-analysis so that we
>> can use the SAF-n-safe tags also with ECLAIR.
>>
>> One question that came up is about multi-line statements. For instance,
>> in a case like the following:
>>
>> diff --git a/xen/common/inflate.c b/xen/common/inflate.c
>> index 8fa4b96d12..8bdc9208da 100644
>> --- a/xen/common/inflate.c
>> +++ b/xen/common/inflate.c
>> @@ -1201,6 +1201,7 @@ static int __init gunzip(void)
>>      magic[1] = NEXTBYTE();
>>      method   = NEXTBYTE();
>>
>> +    /* SAF-1-safe */
>>      if (magic[0] != 037 ||
>>          ((magic[1] != 0213) && (magic[1] != 0236))) {
>>          error("bad gzip magic numbers");
>>
>>
>> Would SAF-1-safe cover both 037, and also 0213 and 0213?
>> Or would it cover only 037?
>>
>> We haven't use SAFE-n-safe extensively through the codebase yet but
>> my understanding is that SAFE-n-safe would cover the entire statement of
>> the following line, even if it is multi-line. Is that also your
>> understanding? Does it work like that with cppcheck?
> Looking at the docs and the actual script, only the single line below SAF 
> comment is excluded.
> So in your case you would require:
> 
> /* SAF-1-safe */
> if (magic[0] != 037 ||
>     /* SAF-1-safe */
>     ((magic[1] != 0213) && (magic[1] != 0236))) {
>     error("bad gzip magic numbers");

Or (perhaps more neatly):

    /* SAF-1-safe */
    if (magic[0] != 037 || (magic[1] != 0213 && magic[1] != 0236)) {
        error("bad gzip magic numbers");

Jan