net: ena: PHC: Check return code before setting timestamp output

In the Linux kernel, the following vulnerability has been resolved:

net: ena: PHC: Check return code before setting timestamp output

ena_phc_gettimex64() is setting the output parameter regardless

of whether ena_com_phc_get_timestamp() succeeded or failed.

When ena_com_phc_get_timestamp() returns an error, the timestamp

parameter may contain uninitialized stack memory (e.g., when PHC is

disabled or in blocked state) or invalid hardware values. Passing

these to userspace via the PTP ioctl is both a security issue

(information leak) and a correctness bug.

Fix by checking the return code after releasing the lock and only

setting the output timestamp on success.