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From: Dan Carpenter <dan.carpenter@oracle.com>
To: Stanislaw Gruszka <sgruszka@redhat.com>
Cc: Helmut Schaa <helmut.schaa@googlemail.com>,
	Kalle Valo <kvalo@codeaurora.org>,
	linux-wireless@vger.kernel.org, kernel-janitors@vger.kernel.org
Subject: [patch] rt2x00: type bug in _rt2500usb_register_read()
Date: Thu, 26 Nov 2015 14:55:23 +0300	[thread overview]
Message-ID: <20151126115523.GD10556@mwanda> (raw)

This code causes a static checker bug.

drivers/net/wireless/ralink/rt2x00/rt2500usb.c:232 _rt2500usb_register_read()
warn: passing casted pointer 'value' to 'rt2500usb_register_read()' 32 vs 16.

If the low 16 bits were initialized to zero then this code would only be
a problem on big endian systems.  But in this case this is case the low
16 bits are never initialized.  This is called from a function which is
created using a macro:

RT2X00DEBUGFS_OPS(csr, "0x%.8x\n", u32);

We end up copying uninitialized data to the user which is bogus and an
information leak.

Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
---
Not tested.  Perhaps we should just remove this code since it has never
worked.

diff --git a/drivers/net/wireless/ralink/rt2x00/rt2500usb.c b/drivers/net/wireless/ralink/rt2x00/rt2500usb.c
index b50d873..d26018f 100644
--- a/drivers/net/wireless/ralink/rt2x00/rt2500usb.c
+++ b/drivers/net/wireless/ralink/rt2x00/rt2500usb.c
@@ -229,7 +229,10 @@ static void _rt2500usb_register_read(struct rt2x00_dev *rt2x00dev,
 				     const unsigned int offset,
 				     u32 *value)
 {
-	rt2500usb_register_read(rt2x00dev, offset, (u16 *)value);
+	u16 tmp;
+
+	rt2500usb_register_read(rt2x00dev, offset, &tmp);
+	*value = tmp;
 }
 
 static void _rt2500usb_register_write(struct rt2x00_dev *rt2x00dev,

             reply	other threads:[~2015-11-26 11:55 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-11-26 11:55 Dan Carpenter [this message]
2015-11-26 12:21 ` [patch] rt2x00: type bug in _rt2500usb_register_read() walter harms
2015-11-26 12:36   ` Dan Carpenter
2015-11-26 13:52 ` Stanislaw Gruszka
2015-11-30 12:58 ` Kalle Valo

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