strncpy() is deprecated for use on NUL-terminated destination strings
[1] and as such we should prefer more robust and less ambiguous string
interfaces.
We expect both data->subsysnqn and data->hostnqn to be NUL-terminated
based on their usage with format specifier ("%s"):
fabrics.c:
322: dev_err(ctrl->device,
323: "%s, subsysnqn \"%s\"\n",
324: inv_data, data->subsysnqn);
...
349: dev_err(ctrl->device,
350: "Connect for subsystem %s is not allowed, hostnqn: %s\n",
351: data->subsysnqn, data->hostnqn);
Moreover, there's no need to NUL-pad since `data` is zero-allocated
already in fabrics.c:
383: data = kzalloc(sizeof(*data), GFP_KERNEL);
... therefore any further NUL-padding is rendered useless.
Considering the above, a suitable replacement is `strscpy` [2] due to
the fact that it guarantees NUL-termination on the destination buffer
without unnecessarily NUL-padding.
I opted not to switch NVMF_NQN_SIZE to sizeof(data->xyz) because the
size is defined as:
| /* NQN names in commands fields specified one size */
| #define NVMF_NQN_FIELD_LEN 256
... while NVMF_NQN_SIZE is defined as:
| /* However the max length of a qualified name is another size */
| #define NVMF_NQN_SIZE 223
Since 223 seems pretty magic, I'm not going to touch it.
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>
---
Note: build-tested only.
Found with: $ rg "strncpy\("
---
drivers/nvme/host/fabrics.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/drivers/nvme/host/fabrics.c b/drivers/nvme/host/fabrics.c
index 8175d49f2909..57aad3ce311a 100644
--- a/drivers/nvme/host/fabrics.c
+++ b/drivers/nvme/host/fabrics.c
@@ -386,8 +386,8 @@ static struct nvmf_connect_data
*nvmf_connect_data_prep(struct nvme_ctrl *ctrl,
uuid_copy(&data->hostid, &ctrl->opts->host->id);
data->cntlid = cpu_to_le16(cntlid);
- strncpy(data->subsysnqn, ctrl->opts->subsysnqn, NVMF_NQN_SIZE);
- strncpy(data->hostnqn, ctrl->opts->host->nqn, NVMF_NQN_SIZE);
+ strscpy(data->subsysnqn, ctrl->opts->subsysnqn, NVMF_NQN_SIZE);
+ strscpy(data->hostnqn, ctrl->opts->host->nqn, NVMF_NQN_SIZE);
return data;
}
---
base-commit: 58720809f52779dc0f08e53e54b014209d13eebb
change-id: 20231018-strncpy-drivers-nvme-host-fabrics-c-416258a22598
Best regards,
--
Justin Stitt <justinst...@google.com>
