[PATCH v6] linux: Add openat2 (BZ 31664)

[Adhemerval Zanella Netto]

On 18/11/25 16:12, Paul Eggert wrote:
> On 2025-11-10 08:19, Adhemerval Zanella wrote:
>> +extern int openat2 (int __dfd, const char *__restrict __filename,
>> +            const struct open_how *__restrict __how,
>> +            size_t __usize)
>> +     __nonnull ((2, 3));
> 
> Shouldn't this be fortified at compile time, by using __builtin_object_size to check that __usize <= sizeof *__how, when fortify checking is enabled?

I am not sure how useful this would be, the kernel will return an error
if user pass an invalid value and in theory if the open_how is extended
user still make a valid call with '__ussize <= sizeof *__how' as long
the size refers to a valid size.

The fortify wrapper would need to handle all the open_how possible
versions, or just support the latest one.