2023-09-22 05:25:05

by Justin Stitt

Subject: [PATCH] IB/qib: replace deprecated strncpy

`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 know `txselect_list` is expected to be NUL-terminated based on its
use in `param_get_string()`:
| int param_get_string(char *buffer, const struct kernel_param *kp)
| {
| const struct kparam_string *kps = kp->str;
| return scnprintf(buffer, PAGE_SIZE, "%s\n", kps->string);
| }

Note that `txselect_list` is assigned to `kp_txselect`'s string field:
| static struct kparam_string kp_txselect = {
| .string = txselect_list,
| .maxlen = MAX_ATTEN_LEN
| };

Wherein it is then assigned the set and get methods:
| module_param_call(txselect, setup_txselect, param_get_string,
| &kp_txselect, S_IWUSR | S_IRUGO);

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.

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: [email protected]
Signed-off-by: Justin Stitt <[email protected]>
---
Note: build-tested
---
drivers/infiniband/hw/qib/qib_iba7322.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/infiniband/hw/qib/qib_iba7322.c b/drivers/infiniband/hw/qib/qib_iba7322.c
index 9d2dd135b784..f93906d8fc09 100644
--- a/drivers/infiniband/hw/qib/qib_iba7322.c
+++ b/drivers/infiniband/hw/qib/qib_iba7322.c
@@ -6127,7 +6127,7 @@ static int setup_txselect(const char *str, const struct kernel_param *kp)
TXDDS_TABLE_SZ + TXDDS_EXTRA_SZ + TXDDS_MFG_SZ);
return -EINVAL;
}
- strncpy(txselect_list, str, ARRAY_SIZE(txselect_list) - 1);
+ strscpy(txselect_list, str, sizeof(txselect_list));

xa_for_each(&qib_dev_table, index, dd)
if (dd->deviceid == PCI_DEVICE_ID_QLOGIC_IB_7322)

---
base-commit: 2cf0f715623872823a72e451243bbf555d10d032
change-id: 20230921-strncpy-drivers-infiniband-hw-qib-qib_iba7322-c-48d5b8f603ee

Best regards,
--
Justin Stitt <[email protected]>

2023-09-22 10:36:48

by Leon Romanovsky

Subject: Re: [PATCH] IB/qib: replace deprecated strncpy

On Thu, 21 Sep 2023 07:58:48 +0000, Justin Stitt wrote:
> `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 know `txselect_list` is expected to be NUL-terminated based on its
> use in `param_get_string()`:
> | int param_get_string(char *buffer, const struct kernel_param *kp)
> | {
> | const struct kparam_string *kps = kp->str;
> | return scnprintf(buffer, PAGE_SIZE, "%s\n", kps->string);
> | }
>
> [...]

Applied, thanks!

[1/1] IB/qib: replace deprecated strncpy
https://git.kernel.org/rdma/rdma/c/cb7ab7854bc709

Best regards,
--
Leon Romanovsky <[email protected]>