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Date:   Wed, 13 Sep 2023 20:23:02 +0000
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Message-ID: <20230913-strncpy-drivers-firmware-ti_sci-c-v1-1-740db471110d@google.com>
Subject: [PATCH] firmware: ti_sci: refactor deprecated strncpy
From:   Justin Stitt <justinstitt@google.com>
To:     Nishanth Menon <nm@ti.com>, Tero Kristo <kristo@kernel.org>,
        Santosh Shilimkar <ssantosh@kernel.org>
Cc:     linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org,
        linux-hardening@vger.kernel.org,
        Justin Stitt <justinstitt@google.com>
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Precedence: bulk

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

We should prefer more robust and less ambiguous string interfaces.

A suitable replacement is `strscpy` [2] due to the fact that it guarantees
NUL-termination on the destination buffer.

It does not seem like `ver->firmware_description` requires NUL-padding
(which is a behavior that strncpy provides) but if it does let's opt for
`strscpy_pad()`.

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/firmware/ti_sci.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/firmware/ti_sci.c b/drivers/firmware/ti_sci.c
index 26a37f47f4ca..ce546f391959 100644
--- a/drivers/firmware/ti_sci.c
+++ b/drivers/firmware/ti_sci.c
@@ -485,7 +485,7 @@ static int ti_sci_cmd_get_revision(struct ti_sci_info *info)
 	ver->abi_major = rev_info->abi_major;
 	ver->abi_minor = rev_info->abi_minor;
 	ver->firmware_revision = rev_info->firmware_revision;
-	strncpy(ver->firmware_description, rev_info->firmware_description,
+	strscpy(ver->firmware_description, rev_info->firmware_description,
 		sizeof(ver->firmware_description));
 
 fail:

---
base-commit: 3669558bdf354cd352be955ef2764cde6a9bf5ec
change-id: 20230913-strncpy-drivers-firmware-ti_sci-c-22667413c18f

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