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From:   Hui Peng <benquike@gmail.com>
To:     security@kernel.org
Cc:     Hui Peng <benquike@gmail.com>,
        Mathias Payer <mathias.payer@nebelwelt.net>,
        Kalle Valo <kvalo@codeaurora.org>,
        "David S. Miller" <davem@davemloft.net>,
        linux-wireless@vger.kernel.org, netdev@vger.kernel.org,
        linux-kernel@vger.kernel.org
Subject: [PATCH] Fix a double free bug in rsi_91x_deinit
Date:   Mon, 19 Aug 2019 18:02:29 -0400
Message-Id: <20190819220230.10597-1-benquike@gmail.com>
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

`dev` (struct rsi_91x_usbdev *) field of adapter
(struct rsi_91x_usbdev *) is allocated  and initialized in
`rsi_init_usb_interface`. If any error is detected in information
read from the device side,  `rsi_init_usb_interface` will be
freed. However, in the higher level error handling code in
`rsi_probe`, if error is detected, `rsi_91x_deinit` is called
again, in which `dev` will be freed again, resulting double free.

This patch fixes the double free by removing the free operation on
`dev` in `rsi_init_usb_interface`, because `rsi_91x_deinit` is also
used in `rsi_disconnect`, in that code path, the `dev` field is not
 (and thus needs to be) freed.

This bug was found in v4.19, but is also present in the latest version
of kernel.

Reported-by: Hui Peng <benquike@gmail.com>
Reported-by: Mathias Payer <mathias.payer@nebelwelt.net>
Signed-off-by: Hui Peng <benquike@gmail.com>
---
 drivers/net/wireless/rsi/rsi_91x_usb.c | 1 -
 1 file changed, 1 deletion(-)

diff --git a/drivers/net/wireless/rsi/rsi_91x_usb.c b/drivers/net/wireless/rsi/rsi_91x_usb.c
index c0a163e40402..ac917227f708 100644
--- a/drivers/net/wireless/rsi/rsi_91x_usb.c
+++ b/drivers/net/wireless/rsi/rsi_91x_usb.c
@@ -640,7 +640,6 @@ static int rsi_init_usb_interface(struct rsi_hw *adapter,
 	kfree(rsi_dev->tx_buffer);
 
 fail_eps:
-	kfree(rsi_dev);
 
 	return status;
 }
-- 
2.22.1