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From: Zack Rusin <zack.rusin@broadcom.com>
To: linux-kernel@vger.kernel.org
Cc: Zack Rusin <zack.rusin@broadcom.com>,
	Dmitry Torokhov <dmitry.torokhov@gmail.com>,
	Arnd Bergmann <arnd@arndb.de>,
	Robert Jarzmik <robert.jarzmik@free.fr>,
	Raul Rangel <rrangel@chromium.org>,
	linux-input@vger.kernel.org,
	stable@vger.kernel.org
Subject: [PATCH v2] input/vmmouse: Fix device name copies
Date: Thu,  4 Jan 2024 00:06:05 -0500
Message-Id: <20240104050605.1773158-1-zack.rusin@broadcom.com>
In-Reply-To: <20231127204206.3593559-1-zack@kde.org>
References: <20231127204206.3593559-1-zack@kde.org>
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Make sure vmmouse_data::phys can hold serio::phys (which is 32 bytes)
plus an extra string, extend it to 64.

Fixes gcc13 warnings:
drivers/input/mouse/vmmouse.c: In function ‘vmmouse_init’:
drivers/input/mouse/vmmouse.c:455:53: warning: ‘/input1’ directive output may be truncated writing 7 bytes into a region of size between 1 and 32 [-Wformat-truncation=]
  455 |         snprintf(priv->phys, sizeof(priv->phys), "%s/input1",
      |                                                     ^~~~~~~
drivers/input/mouse/vmmouse.c:455:9: note: ‘snprintf’ output between 8 and 39 bytes into a destination of size 32
  455 |         snprintf(priv->phys, sizeof(priv->phys), "%s/input1",
      |         ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  456 |                  psmouse->ps2dev.serio->phys);
      |                  ~~~~~~~~~~~~~~~~~~~~~~~~~~~~

v2: Use the exact size for the vmmouse_data::phys

Signed-off-by: Zack Rusin <zack.rusin@broadcom.com>
Fixes: 8b8be51b4fd3 ("Input: add vmmouse driver")
Cc: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Robert Jarzmik <robert.jarzmik@free.fr>
Cc: Raul Rangel <rrangel@chromium.org>
Cc: linux-input@vger.kernel.org
Cc: <stable@vger.kernel.org> # v4.1+
---
 drivers/input/mouse/vmmouse.c | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/drivers/input/mouse/vmmouse.c b/drivers/input/mouse/vmmouse.c
index ea9eff7c8099..74131673e2f3 100644
--- a/drivers/input/mouse/vmmouse.c
+++ b/drivers/input/mouse/vmmouse.c
@@ -63,6 +63,8 @@
 #define VMMOUSE_VENDOR "VMware"
 #define VMMOUSE_NAME   "VMMouse"
 
+#define VMMOUSE_PHYS_NAME_POSTFIX_STR "/input1"
+
 /**
  * struct vmmouse_data - private data structure for the vmmouse driver
  *
@@ -72,7 +74,8 @@
  */
 struct vmmouse_data {
 	struct input_dev *abs_dev;
-	char phys[32];
+	char phys[sizeof_field(struct serio, phys) +
+		  strlen(VMMOUSE_PHYS_NAME_POSTFIX_STR)];
 	char dev_name[128];
 };
 
@@ -452,7 +455,8 @@ int vmmouse_init(struct psmouse *psmouse)
 	psmouse->private = priv;
 
 	/* Set up and register absolute device */
-	snprintf(priv->phys, sizeof(priv->phys), "%s/input1",
+	snprintf(priv->phys, sizeof(priv->phys),
+		 "%s" VMMOUSE_PHYS_NAME_POSTFIX_STR,
 		 psmouse->ps2dev.serio->phys);
 
 	/* Mimic name setup for relative device in psmouse-base.c */
-- 
2.40.1