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From: Pavel Skripkin <paskripkin@gmail.com>
To: petkan@nucleusys.com, davem@davemloft.net, kuba@kernel.org
Cc: linux-usb@vger.kernel.org, netdev@vger.kernel.org,
	linux-kernel@vger.kernel.org,
	Pavel Skripkin <paskripkin@gmail.com>,
	syzbot+02c9f70f3afae308464a@syzkaller.appspotmail.com
Subject: [PATCH] net: pegasus: fix uninit-value in get_interrupt_interval
Date: Sat, 31 Jul 2021 00:44:11 +0300	[thread overview]
Message-ID: <20210730214411.1973-1-paskripkin@gmail.com> (raw)

Syzbot reported uninit value pegasus_probe(). The problem was in missing
error handling.

get_interrupt_interval() internally calls read_eprom_word() which can
fail in some cases. For example: failed to receive usb control message.
These cases should be handled to prevent uninit value bug, since
read_eprom_word() will not initialize passed stack variable in case of
internal failure.

Fail log:

BUG: KMSAN: uninit-value in get_interrupt_interval drivers/net/usb/pegasus.c:746 [inline]
BUG: KMSAN: uninit-value in pegasus_probe+0x10e7/0x4080 drivers/net/usb/pegasus.c:1152
CPU: 1 PID: 825 Comm: kworker/1:1 Not tainted 5.12.0-rc6-syzkaller #0
...
Workqueue: usb_hub_wq hub_event
Call Trace:
 __dump_stack lib/dump_stack.c:79 [inline]
 dump_stack+0x24c/0x2e0 lib/dump_stack.c:120
 kmsan_report+0xfb/0x1e0 mm/kmsan/kmsan_report.c:118
 __msan_warning+0x5c/0xa0 mm/kmsan/kmsan_instr.c:197
 get_interrupt_interval drivers/net/usb/pegasus.c:746 [inline]
 pegasus_probe+0x10e7/0x4080 drivers/net/usb/pegasus.c:1152
....

Local variable ----data.i@pegasus_probe created at:
 get_interrupt_interval drivers/net/usb/pegasus.c:1151 [inline]
 pegasus_probe+0xe57/0x4080 drivers/net/usb/pegasus.c:1152
 get_interrupt_interval drivers/net/usb/pegasus.c:1151 [inline]
 pegasus_probe+0xe57/0x4080 drivers/net/usb/pegasus.c:1152

Reported-and-tested-by: syzbot+02c9f70f3afae308464a@syzkaller.appspotmail.com
Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Signed-off-by: Pavel Skripkin <paskripkin@gmail.com>
---
 drivers/net/usb/pegasus.c | 14 +++++++++++---
 1 file changed, 11 insertions(+), 3 deletions(-)

diff --git a/drivers/net/usb/pegasus.c b/drivers/net/usb/pegasus.c
index 9a907182569c..bc2dbf86496b 100644
--- a/drivers/net/usb/pegasus.c
+++ b/drivers/net/usb/pegasus.c
@@ -735,12 +735,16 @@ static inline void disable_net_traffic(pegasus_t *pegasus)
 	set_registers(pegasus, EthCtrl0, sizeof(tmp), &tmp);
 }
 
-static inline void get_interrupt_interval(pegasus_t *pegasus)
+static inline int get_interrupt_interval(pegasus_t *pegasus)
 {
 	u16 data;
 	u8 interval;
+	int ret;
+
+	ret = read_eprom_word(pegasus, 4, &data);
+	if (ret < 0)
+		return ret;
 
-	read_eprom_word(pegasus, 4, &data);
 	interval = data >> 8;
 	if (pegasus->usb->speed != USB_SPEED_HIGH) {
 		if (interval < 0x80) {
@@ -755,6 +759,8 @@ static inline void get_interrupt_interval(pegasus_t *pegasus)
 		}
 	}
 	pegasus->intr_interval = interval;
+
+	return 0;
 }
 
 static void set_carrier(struct net_device *net)
@@ -1149,7 +1155,9 @@ static int pegasus_probe(struct usb_interface *intf,
 				| NETIF_MSG_PROBE | NETIF_MSG_LINK);
 
 	pegasus->features = usb_dev_id[dev_index].private;
-	get_interrupt_interval(pegasus);
+	res = get_interrupt_interval(pegasus);
+	if (res)
+		goto out2;
 	if (reset_mac(pegasus)) {
 		dev_err(&intf->dev, "can't reset MAC\n");
 		res = -EIO;
-- 
2.32.0


             reply	other threads:[~2021-07-30 21:44 UTC|newest]

Thread overview: 11+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-07-30 21:44 Pavel Skripkin [this message]
2021-08-01 12:36 ` Petko Manolov
2021-08-01 19:35   ` Pavel Skripkin
2021-08-01 20:24     ` Petko Manolov
2021-08-02 20:07     ` Petko Manolov
2021-08-02 22:18       ` Pavel Skripkin
2021-08-03  5:36       ` Greg KH
2021-08-04 10:44 ` Pavel Skripkin
2021-08-04 11:58   ` Jakub Kicinski
2021-08-04 14:30     ` [PATCH net v2] " Pavel Skripkin
2021-08-05 14:50       ` patchwork-bot+netdevbpf

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