[PATCH] x86/hpet: refactor deprecated strncpy

[PATCH] x86/hpet: refactor deprecated strncpy

[Justin Stitt]

`strncpy` is deprecated for use on NUL-terminated destination strings [1].

A suitable replacement is `strscpy` [2] due to the fact that it
guarantees NUL-termination on its destination buffer argument which is
_not_ the case for `strncpy`!

In this case, it is a simple swap from `strncpy` to `strscpy`. There is
one slight difference, though. If NUL-padding is a functional
requirement here we should opt for `strscpy_pad`. It seems like this
shouldn't be needed as I see no obvious signs of any padding being
required.

Link: 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.
---
 arch/x86/kernel/hpet.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/x86/kernel/hpet.c b/arch/x86/kernel/hpet.c
index c8eb1ac5125a..1648aa0204d9 100644
--- a/arch/x86/kernel/hpet.c
+++ b/arch/x86/kernel/hpet.c
@@ -421,7 +421,7 @@ static void __init hpet_legacy_clockevent_register(struct hpet_channel *hc)
 	 * the IO_APIC has been initialized.
 	 */
 	hc->cpu = boot_cpu_data.cpu_index;
-	strncpy(hc->name, "hpet", sizeof(hc->name));
+	strscpy(hc->name, "hpet", sizeof(hc->name));
 	hpet_init_clockevent(hc, 50);
 
 	hc->evt.tick_resume	= hpet_clkevt_legacy_resume;

---
base-commit: 706a741595047797872e669b3101429ab8d378ef
change-id: 20230822-strncpy-arch-x86-kernel-hpet-4d57cbd8eb96

Best regards,
--
Justin Stitt <justinstitt@google.com>

[tip: x86/cleanups] x86/hpet: Refactor code using deprecated strncpy() interface to use strscpy()

[tip-bot2 for Justin Stitt]

The following commit has been merged into the x86/cleanups branch of tip:

Commit-ID:     4108d141bfd04cf7b2bbf96e899ee5392f62e8a2
Gitweb:        https://git.kernel.org/tip/4108d141bfd04cf7b2bbf96e899ee5392f62e8a2
Author:        Justin Stitt <justinstitt@google.com>
AuthorDate:    Tue, 22 Aug 2023 22:13:36 
Committer:     Ingo Molnar <mingo@kernel.org>
CommitterDate: Thu, 24 Aug 2023 21:22:40 +02:00

x86/hpet: Refactor code using deprecated strncpy() interface to use strscpy()

`strncpy` is deprecated for use on NUL-terminated destination strings [1].

A suitable replacement is `strscpy` [2] due to the fact that it
guarantees NUL-termination on its destination buffer argument which is
_not_ the case for `strncpy`!

In this case, it is a simple swap from `strncpy` to `strscpy`. There is
one slight difference, though. If NUL-padding is a functional
requirement here we should opt for `strscpy_pad`. It seems like this
shouldn't be needed as I see no obvious signs of any padding being
required.

Signed-off-by: Justin Stitt <justinstitt@google.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Link: 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
Link: https://lore.kernel.org/r/20230822-strncpy-arch-x86-kernel-hpet-v1-1-2c7d3be86f4a@google.com
---
 arch/x86/kernel/hpet.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/x86/kernel/hpet.c b/arch/x86/kernel/hpet.c
index c8eb1ac..1648aa0 100644
--- a/arch/x86/kernel/hpet.c
+++ b/arch/x86/kernel/hpet.c
@@ -421,7 +421,7 @@ static void __init hpet_legacy_clockevent_register(struct hpet_channel *hc)
 	 * the IO_APIC has been initialized.
 	 */
 	hc->cpu = boot_cpu_data.cpu_index;
-	strncpy(hc->name, "hpet", sizeof(hc->name));
+	strscpy(hc->name, "hpet", sizeof(hc->name));
 	hpet_init_clockevent(hc, 50);
 
 	hc->evt.tick_resume	= hpet_clkevt_legacy_resume;