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Date:   Mon, 23 Oct 2023 19:14:49 +0000
Mime-Version: 1.0
Message-ID: <20231023-strncpy-drivers-s390-char-sclp-c-v1-1-eaeef80522bb@google.com>
Subject: [PATCH] s390/sclp: replace deprecated strncpy with strtomem
From:   Justin Stitt <justinstitt@google.com>
To:     Heiko Carstens <hca@linux.ibm.com>,
        Vasily Gorbik <gor@linux.ibm.com>,
        Alexander Gordeev <agordeev@linux.ibm.com>,
        Christian Borntraeger <borntraeger@linux.ibm.com>,
        Sven Schnelle <svens@linux.ibm.com>
Cc:     linux-s390@vger.kernel.org, linux-kernel@vger.kernel.org,
        linux-hardening@vger.kernel.org,
        Justin Stitt <justinstitt@google.com>
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Precedence: bulk

Let's move away from using strncpy() as it is deprecated [1].

Instead use strtomem() as `e.id` is already marked as nonstring:
|       char id[4] __nonstring;

We don't need strtomem_pad() because `e` is already memset to 0 --
rendering any additional NUL-padding useless.

Link: https://www.kernel.org/doc/html/latest/process/deprecated.html#strncpy-on-nul-terminated-strings [1]
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.

Found with: $ rg "strncpy\("
---
 drivers/s390/char/sclp.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/s390/char/sclp.c b/drivers/s390/char/sclp.c
index 8f74db689a0c..486cf57a1605 100644
--- a/drivers/s390/char/sclp.c
+++ b/drivers/s390/char/sclp.c
@@ -81,7 +81,7 @@ static inline void sclp_trace(int prio, char *id, u32 a, u64 b, bool err)
 	struct sclp_trace_entry e;
 
 	memset(&e, 0, sizeof(e));
-	strncpy(e.id, id, sizeof(e.id));
+	strtomem(e.id, id);
 	e.a = a;
 	e.b = b;
 	debug_event(&sclp_debug, prio, &e, sizeof(e));

---
base-commit: 9c5d00cb7b6bbc5a7965d9ab7d223b5402d1f02c
change-id: 20231023-strncpy-drivers-s390-char-sclp-c-bb66226a7eaa

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