strncpy() is deprecated for use on NUL-terminated destination strings [1] and as such we should prefer more robust and less ambiguous string interfaces.
Let's instead use strscpy() [2] as it guarantees NUL-termination on the destination buffer. Moreover, there is no need to use: | min(FCNVME_ASSOC_HOSTNQN_LEN, NVMF_NQN_SIZE)); I imagine this was originally done to make sure the destination buffer is NUL-terminated by ensuring we copy a number of bytes less than the size of our destination, thus leaving some NUL-bytes at the end. However, with strscpy(), we no longer need to do this and we can instead opt for the more idiomatic strscpy() usage of: | strscpy(dest, src, sizeof(dest)) Also, no NUL-padding is required as lsop is zero-allocated: | lsop = kzalloc((sizeof(*lsop) + | sizeof(*assoc_rqst) + sizeof(*assoc_acc) + | ctrl->lport->ops->lsrqst_priv_sz), GFP_KERNEL); ... and assoc_rqst points to a field in lsop: | assoc_rqst = (struct fcnvme_ls_cr_assoc_rqst *)&lsop[1]; Therefore, any additional NUL-byte assignments (like the ones that strncpy() makes) are redundant. Link: https://www.kernel.org/doc/html/latest/process/deprecated.html#strncpy-on-nul-terminated-strings [1] Link: https://manpages.debian.org/testing/linux-manual-4.8/strscpy.9.en.html [2] Link: https://github.com/KSPP/linux/issues/90 Cc: linux-hardening@vger.kernel.org Signed-off-by: Justin Stitt <justinst...@google.com> Similar-to: https://lore.kernel.org/all/20231018-strncpy-drivers-nvme-host-fabrics-c-v1-1-b6677df40...@google.com/ --- Note: build-tested only. --- drivers/nvme/host/fc.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) diff --git a/drivers/nvme/host/fc.c b/drivers/nvme/host/fc.c index a15b37750d6e..680585253f7c 100644 --- a/drivers/nvme/host/fc.c +++ b/drivers/nvme/host/fc.c @@ -1218,10 +1218,10 @@ nvme_fc_connect_admin_queue(struct nvme_fc_ctrl *ctrl, /* Linux supports only Dynamic controllers */ assoc_rqst->assoc_cmd.cntlid = cpu_to_be16(0xffff); uuid_copy(&assoc_rqst->assoc_cmd.hostid, &ctrl->ctrl.opts->host->id); - strncpy(assoc_rqst->assoc_cmd.hostnqn, ctrl->ctrl.opts->host->nqn, - min(FCNVME_ASSOC_HOSTNQN_LEN, NVMF_NQN_SIZE)); - strncpy(assoc_rqst->assoc_cmd.subnqn, ctrl->ctrl.opts->subsysnqn, - min(FCNVME_ASSOC_SUBNQN_LEN, NVMF_NQN_SIZE)); + strscpy(assoc_rqst->assoc_cmd.hostnqn, ctrl->ctrl.opts->host->nqn, + sizeof(assoc_rqst->assoc_cmd.hostnqn)); + strscpy(assoc_rqst->assoc_cmd.subnqn, ctrl->ctrl.opts->subsysnqn, + sizeof(assoc_rqst->assoc_cmd.subnqn)); lsop->queue = queue; lsreq->rqstaddr = assoc_rqst; --- base-commit: dab3e01664eaddae965699f1fec776609db0ea9d change-id: 20231019-strncpy-drivers-nvme-host-fc-c-a542b34b8710 Best regards, -- Justin Stitt <justinst...@google.com>
