| Message ID | 20230922-strncpy-drivers-isdn-misdn-clock-c-v1-1-3ba2a5ae627a@google.com (mailing list archive) |
|---|---|
| State | Not Applicable |
| Headers | show |
| Series | isdn: replace deprecated strncpy with strscpy | expand |
| Context | Check | Description |
|---|---|---|
| netdev/tree_selection | success | Not a local patch |
On Fri, Sep 22, 2023 at 11:58:06AM +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 expect `iclock->name` to be NUL-terminated based on its use within > printk: > | printk(KERN_DEBUG "%s: %s %d\n", __func__, iclock->name, > | iclock->pri); > > `iclock` is zero-initialized and as such is already NUL-padded which > means strncpy is doing extra work here by eagerly NUL-padding the > destination buffer. > > 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: linux-hardening@vger.kernel.org > Signed-off-by: Justin Stitt <justinstitt@google.com> Yup, looks like a clean replacement. Reviewed-by: Kees Cook <keescook@chromium.org>
On Fri, 22 Sep 2023 11:58:06 +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 expect `iclock->name` to be NUL-terminated based on its use within > printk: > | printk(KERN_DEBUG "%s: %s %d\n", __func__, iclock->name, > | iclock->pri); > > [...] Applied to for-next/hardening, thanks! [1/1] isdn: replace deprecated strncpy with strscpy https://git.kernel.org/kees/c/a9b065a6751b Take care,
diff --git a/drivers/isdn/mISDN/clock.c b/drivers/isdn/mISDN/clock.c index 01d878168ef2..f71eb61db131 100644 --- a/drivers/isdn/mISDN/clock.c +++ b/drivers/isdn/mISDN/clock.c @@ -96,7 +96,7 @@ struct mISDNclock printk(KERN_ERR "%s: No memory for clock entry.\n", __func__); return NULL; } - strncpy(iclock->name, name, sizeof(iclock->name) - 1); + strscpy(iclock->name, name, sizeof(iclock->name)); iclock->pri = pri; iclock->priv = priv; iclock->ctl = ctl;
`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 `iclock->name` to be NUL-terminated based on its use within printk: | printk(KERN_DEBUG "%s: %s %d\n", __func__, iclock->name, | iclock->pri); `iclock` is zero-initialized and as such is already NUL-padded which means strncpy is doing extra work here by eagerly NUL-padding the destination buffer. 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: linux-hardening@vger.kernel.org Signed-off-by: Justin Stitt <justinstitt@google.com> --- Note: build-tested only. --- drivers/isdn/mISDN/clock.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- base-commit: 2cf0f715623872823a72e451243bbf555d10d032 change-id: 20230922-strncpy-drivers-isdn-misdn-clock-c-2d32a23b8c2d Best regards, -- Justin Stitt <justinstitt@google.com>