linux-hardening - [PATCH v4] net: dsa: lan9303: use ethtool_puts() for lan9303_get

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [thread-next>] [day] [month] [year] [list]

Date: Thu, 25 Apr 2024 01:19:13 +0000
From: Justin Stitt <justinstitt@...gle.com>
To: Andrew Lunn <andrew@...n.ch>, Florian Fainelli <f.fainelli@...il.com>, 
	Vladimir Oltean <olteanv@...il.com>, "David S. Miller" <davem@...emloft.net>, 
	Eric Dumazet <edumazet@...gle.com>, Jakub Kicinski <kuba@...nel.org>, Paolo Abeni <pabeni@...hat.com>
Cc: netdev@...r.kernel.org, linux-kernel@...r.kernel.org, 
	linux-hardening@...r.kernel.org, Kees Cook <keescook@...omium.org>, 
	Alexander Lobakin <aleksander.lobakin@...el.com>, Justin Stitt <justinstitt@...gle.com>
Subject: [PATCH v4] net: dsa: lan9303: use ethtool_puts() for lan9303_get_strings()

This pattern of strncpy with some pointer arithmetic setting fixed-sized
intervals with string literal data is a bit weird so let's use
ethtool_puts() as this has more obvious behavior and is less-error
prone.

Nicely, we also get to drop a usage of the now deprecated strncpy() [1].

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@...r.kernel.org
Cc: Kees Cook <keescook@...omium.org>
Suggested-by: Alexander Lobakin <aleksander.lobakin@...el.com>
Reviewed-by: Kees Cook <keescook@...omium.org>
Signed-off-by: Justin Stitt <justinstitt@...gle.com>
---
Changes in v4:
- drop unnecessary { } (thanks Alexander L.)
- carry Kees' RB because of trivial change
- Link to v3: https://lore.kernel.org/r/20240408-strncpy-drivers-net-dsa-lan9303-core-c-v3-1-0c313694d25b@google.com

Changes in v3:
- use ethtool_puts over ethtool_sprintf
- Link to v2: https://lore.kernel.org/r/20231005-strncpy-drivers-net-dsa-lan9303-core-c-v2-1-feb452a532db@google.com

Changes in v2:
- use ethtool_sprintf (thanks Alexander)
- Link to v1: https://lore.kernel.org/r/20231005-strncpy-drivers-net-dsa-lan9303-core-c-v1-1-5a66c538147e@google.com
---
 drivers/net/dsa/lan9303-core.c | 7 +++----
 1 file changed, 3 insertions(+), 4 deletions(-)

diff --git a/drivers/net/dsa/lan9303-core.c b/drivers/net/dsa/lan9303-core.c
index fcb20eac332a..f3b50adae865 100644
--- a/drivers/net/dsa/lan9303-core.c
+++ b/drivers/net/dsa/lan9303-core.c
@@ -1007,15 +1007,14 @@ static const struct lan9303_mib_desc lan9303_mib[] = {
 static void lan9303_get_strings(struct dsa_switch *ds, int port,
 				u32 stringset, uint8_t *data)
 {
+	u8 *buf = data;
 	unsigned int u;
 
 	if (stringset != ETH_SS_STATS)
 		return;
 
-	for (u = 0; u < ARRAY_SIZE(lan9303_mib); u++) {
-		strncpy(data + u * ETH_GSTRING_LEN, lan9303_mib[u].name,
-			ETH_GSTRING_LEN);
-	}
+	for (u = 0; u < ARRAY_SIZE(lan9303_mib); u++)
+		ethtool_puts(&buf, lan9303_mib[u].name);
 }
 
 static void lan9303_get_ethtool_stats(struct dsa_switch *ds, int port,

---
base-commit: c85af715cac0a951eea97393378e84bb49384734
change-id: 20231005-strncpy-drivers-net-dsa-lan9303-core-c-6386858e5c22

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