From: Justin Stitt <justinstitt@google.com>
To: James Smart <james.smart@broadcom.com>,
Keith Busch <kbusch@kernel.org>, Jens Axboe <axboe@kernel.dk>,
Christoph Hellwig <hch@lst.de>, Sagi Grimberg <sagi@grimberg.me>
Cc: linux-nvme@lists.infradead.org, linux-kernel@vger.kernel.org,
linux-hardening@vger.kernel.org,
Justin Stitt <justinstitt@google.com>
Subject: [PATCH] nvme-fc: replace deprecated strncpy with strscpy
Date: Thu, 19 Oct 2023 21:34:35 +0000 [thread overview]
Message-ID: <20231019-strncpy-drivers-nvme-host-fc-c-v1-1-5805c15e4b49@google.com> (raw)
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 <justinstitt@google.com>
Similar-to: https://lore.kernel.org/all/20231018-strncpy-drivers-nvme-host-fabrics-c-v1-1-b6677df40a35@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 <justinstitt@google.com>
next reply other threads:[~2023-10-19 21:34 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-10-19 21:34 Justin Stitt [this message]
2023-10-19 23:20 ` [PATCH] nvme-fc: replace deprecated strncpy with strscpy Kees Cook
2023-11-30 22:01 ` Kees Cook
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