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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org,
        syzbot+e27b4fd589762b0b9329@syzkaller.appspotmail.com,
        Dongliang Mu <mudongliangabcd@gmail.com>,
        Sean Young <sean@mess.org>,
        Mauro Carvalho Chehab <mchehab+huawei@kernel.org>,
        Sasha Levin <sashal@kernel.org>
Subject: [PATCH 4.4 038/133] media: dvb-usb: fix uninit-value in dvb_usb_adapter_dvb_init
Date:   Mon, 20 Sep 2021 18:41:56 +0200
Message-Id: <20210920163913.887114722@linuxfoundation.org>
In-Reply-To: <20210920163912.603434365@linuxfoundation.org>
References: <20210920163912.603434365@linuxfoundation.org>
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From: Dongliang Mu <mudongliangabcd@gmail.com>

[ Upstream commit c5453769f77ce19a5b03f1f49946fd3f8a374009 ]

If dibusb_read_eeprom_byte fails, the mac address is not initialized.
And nova_t_read_mac_address does not handle this failure, which leads to
the uninit-value in dvb_usb_adapter_dvb_init.

Fix this by handling the failure of dibusb_read_eeprom_byte.

Reported-by: syzbot+e27b4fd589762b0b9329@syzkaller.appspotmail.com
Fixes: 786baecfe78f ("[media] dvb-usb: move it to drivers/media/usb/dvb-usb")
Signed-off-by: Dongliang Mu <mudongliangabcd@gmail.com>
Signed-off-by: Sean Young <sean@mess.org>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/media/usb/dvb-usb/nova-t-usb2.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/drivers/media/usb/dvb-usb/nova-t-usb2.c b/drivers/media/usb/dvb-usb/nova-t-usb2.c
index 6c55384e2fca..c570c4af64f3 100644
--- a/drivers/media/usb/dvb-usb/nova-t-usb2.c
+++ b/drivers/media/usb/dvb-usb/nova-t-usb2.c
@@ -122,7 +122,7 @@ static int nova_t_rc_query(struct dvb_usb_device *d, u32 *event, int *state)
 
 static int nova_t_read_mac_address (struct dvb_usb_device *d, u8 mac[6])
 {
-	int i;
+	int i, ret;
 	u8 b;
 
 	mac[0] = 0x00;
@@ -131,7 +131,9 @@ static int nova_t_read_mac_address (struct dvb_usb_device *d, u8 mac[6])
 
 	/* this is a complete guess, but works for my box */
 	for (i = 136; i < 139; i++) {
-		dibusb_read_eeprom_byte(d,i, &b);
+		ret = dibusb_read_eeprom_byte(d, i, &b);
+		if (ret)
+			return ret;
 
 		mac[5 - (i - 136)] = b;
 	}
-- 
2.30.2