Re: [PATCH 4.19 079/422] i40e: use correct length for strncpy

Hi!

From: Mitch Williams mitch.a.williams@intel.com

[ Upstream commit 7eb74ff891b4e94b8bac48f648a21e4b94ddee64 ]

Caught by GCC 8. When we provide a length for strncpy, we should not include the terminating null. So we must tell it one less than the size of the destination buffer.

+++ b/drivers/net/ethernet/intel/i40e/i40e_ptp.c @@ -694,7 +694,8 @@ static long i40e_ptp_create_clock(struct i40e_pf *pf) if (!IS_ERR_OR_NULL(pf->ptp_clock)) return 0;

• strncpy(pf->ptp_caps.name, i40e_driver_name, sizeof(pf->ptp_caps.name));

• strncpy(pf->ptp_caps.name, i40e_driver_name,

• sizeof(pf->ptp_caps.name) - 1);
  

  pf->ptp_caps.owner = THIS_MODULE; pf->ptp_caps.max_adj = 999999999; pf->ptp_caps.n_ext_ts = 0;

So... pf is allocated with kzalloc, which will provide the null termination... so the code is okay.

On the other hand, the = 0 below is unneeded by the same logic, so this is a bit confusing.

Best regards, Pavel