linux-kernel - [PATCH] can: ucan: the memory allocated to ctl_msg

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Message-ID: <20250327064319.3001956-1-lizhi.xu@windriver.com>
Date: Thu, 27 Mar 2025 14:43:18 +0800
From: Lizhi Xu <lizhi.xu@...driver.com>
To: <syzbot+79340d79a8ed013a2313@...kaller.appspotmail.com>
CC: <linux-can@...r.kernel.org>, <linux-kernel@...r.kernel.org>,
        <linux-usb@...r.kernel.org>, <mailhol.vincent@...adoo.fr>,
        <mkl@...gutronix.de>, <syzkaller-bugs@...glegroups.com>
Subject: [PATCH] can: ucan: the memory allocated to ctl_msg_buffer is one byte less

When executing strscpy to copy data from ctl_msg_buffer->raw to firmware_str,
the length of the raw is sizeof(union ucan_ctl_payload) + 1, which is larger
than the one byte allocated to ctl_msg_buffer.

Fixes: 7fdaf8966aae ("can: ucan: use strscpy() to instead of strncpy()")
Reported-by: syzbot+79340d79a8ed013a2313@...kaller.appspotmail.com
Closes: https://syzkaller.appspot.com/bug?extid=79340d79a8ed013a2313
Tested-by: syzbot+79340d79a8ed013a2313@...kaller.appspotmail.com
Signed-off-by: Lizhi Xu <lizhi.xu@...driver.com>
---
 drivers/net/can/usb/ucan.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/net/can/usb/ucan.c b/drivers/net/can/usb/ucan.c
index 39a63b7313a4..97c6cfa2d011 100644
--- a/drivers/net/can/usb/ucan.c
+++ b/drivers/net/can/usb/ucan.c
@@ -1399,7 +1399,7 @@ static int ucan_probe(struct usb_interface *intf,
 
 	/* Prepare Memory for control transfers */
 	ctl_msg_buffer = devm_kzalloc(&udev->dev,
-				      sizeof(union ucan_ctl_payload),
+				      sizeof(union ucan_ctl_payload) + 1,
 				      GFP_KERNEL);
 	if (!ctl_msg_buffer) {
 		dev_err(&udev->dev,
-- 
2.43.0