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From: Haowen Bai <baihaowen@meizu.com>
To: <linux@roeck-us.net>, <heikki.krogerus@linux.intel.com>,
	<gregkh@linuxfoundation.org>
Cc: <linux-usb@vger.kernel.org>, <linux-kernel@vger.kernel.org>,
	Haowen Bai <baihaowen@meizu.com>
Subject: [PATCH] usb: typec: tcpm: testing array offset 'port->logbuffer_head' before use
Date: Fri, 25 Mar 2022 12:34:09 +0800	[thread overview]
Message-ID: <1648182849-9209-1-git-send-email-baihaowen@meizu.com> (raw)

Fix possible indexing array of bound for 
port->logbuffer[port->logbuffer_head], where port->logbuffer_head boundary
 check happens later. so we do it before.

Signed-off-by: Haowen Bai <baihaowen@meizu.com>
---
 drivers/usb/typec/tcpm/tcpm.c | 15 ++++++++-------
 1 file changed, 8 insertions(+), 7 deletions(-)

diff --git a/drivers/usb/typec/tcpm/tcpm.c b/drivers/usb/typec/tcpm/tcpm.c
index 5fce795..541e9e4 100644
--- a/drivers/usb/typec/tcpm/tcpm.c
+++ b/drivers/usb/typec/tcpm/tcpm.c
@@ -591,6 +591,14 @@ static void _tcpm_log(struct tcpm_port *port, const char *fmt, va_list args)
 	unsigned long rem_nsec;
 
 	mutex_lock(&port->logbuffer_lock);
+
+	if (port->logbuffer_head < 0 ||
+	    port->logbuffer_head >= LOG_BUFFER_ENTRIES) {
+		dev_warn(port->dev,
+			 "Bad log buffer index %d\n", port->logbuffer_head);
+		goto abort;
+	}
+
 	if (!port->logbuffer[port->logbuffer_head]) {
 		port->logbuffer[port->logbuffer_head] =
 				kzalloc(LOG_BUFFER_ENTRY_SIZE, GFP_KERNEL);
@@ -607,13 +615,6 @@ static void _tcpm_log(struct tcpm_port *port, const char *fmt, va_list args)
 		strcpy(tmpbuffer, "overflow");
 	}
 
-	if (port->logbuffer_head < 0 ||
-	    port->logbuffer_head >= LOG_BUFFER_ENTRIES) {
-		dev_warn(port->dev,
-			 "Bad log buffer index %d\n", port->logbuffer_head);
-		goto abort;
-	}
-
 	if (!port->logbuffer[port->logbuffer_head]) {
 		dev_warn(port->dev,
 			 "Log buffer index %d is NULL\n", port->logbuffer_head);
-- 
2.7.4


             reply	other threads:[~2022-03-25  4:34 UTC|newest]

Thread overview: 2+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-03-25  4:34 Haowen Bai [this message]
2022-03-25  4:45 ` [PATCH] usb: typec: tcpm: testing array offset 'port->logbuffer_head' before use Guenter Roeck

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