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Date:   Sat, 30 Oct 2021 22:42:50 -0400
From:   Zekun Shen <bruceshenzk@gmail.com>
To:     bruceshenzk@gmail.com
Cc:     Amitkumar Karwar <amitkarwar@gmail.com>,
        Ganapathi Bhat <ganapathi017@gmail.com>,
        Sharvari Harisangam <sharvari.harisangam@nxp.com>,
        Xinming Hu <huxinming820@gmail.com>,
        Kalle Valo <kvalo@codeaurora.org>,
        "David S. Miller" <davem@davemloft.net>,
        Jakub Kicinski <kuba@kernel.org>,
        linux-wireless@vger.kernel.org, netdev@vger.kernel.org,
        linux-kernel@vger.kernel.org, brendandg@nyu.edu
Subject: [PATCH] mwifiex_usb: Fix skb_over_panic in mwifiex_usb_recv
Message-ID: <YX4CqjfRcTa6bVL+@Zekuns-MBP-16.fios-router.home>
MIME-Version: 1.0
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Precedence: bulk

Currently, with an unknown recv_type, mwifiex_usb_recv
just return -1 without restoring the skb. Next time
mwifiex_usb_rx_complete is invoked with the same skb,
calling skb_put causes skb_over_panic.

The bug is triggerable with a compromised/malfunctioning
usb device. After applying the patch, skb_over_panic
no longer shows up with the same input.

Attached is the panic report from fuzzing.
skbuff: skb_over_panic: text:000000003bf1b5fa
 len:2048 put:4 head:00000000dd6a115b data:000000000a9445d8
 tail:0x844 end:0x840 dev:<NULL>
kernel BUG at net/core/skbuff.c:109!
invalid opcode: 0000 [#1] SMP KASAN NOPTI
CPU: 0 PID: 198 Comm: in:imklog Not tainted 5.6.0 #60
RIP: 0010:skb_panic+0x15f/0x161
Call Trace:
 <IRQ>
 ? mwifiex_usb_rx_complete+0x26b/0xfcd [mwifiex_usb]
 skb_put.cold+0x24/0x24
 mwifiex_usb_rx_complete+0x26b/0xfcd [mwifiex_usb]
 __usb_hcd_giveback_urb+0x1e4/0x380
 usb_giveback_urb_bh+0x241/0x4f0
 ? __hrtimer_run_queues+0x316/0x740
 ? __usb_hcd_giveback_urb+0x380/0x380
 tasklet_action_common.isra.0+0x135/0x330
 __do_softirq+0x18c/0x634
 irq_exit+0x114/0x140
 smp_apic_timer_interrupt+0xde/0x380
 apic_timer_interrupt+0xf/0x20
 </IRQ>

Reported-by: Zekun Shen <bruceshenzk@gmail.com>
Reported-by: Brendan Dolan-Gavitt <brendandg@nyu.edu>
Signed-off-by: Zekun Shen <bruceshenzk@gmail.com>
---
 drivers/net/wireless/marvell/mwifiex/usb.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/net/wireless/marvell/mwifiex/usb.c b/drivers/net/wireless/marvell/mwifiex/usb.c
index 426e39d4c..6d81e8786 100644
--- a/drivers/net/wireless/marvell/mwifiex/usb.c
+++ b/drivers/net/wireless/marvell/mwifiex/usb.c
@@ -130,7 +130,8 @@ static int mwifiex_usb_recv(struct mwifiex_adapter *adapter,
 		default:
 			mwifiex_dbg(adapter, ERROR,
 				    "unknown recv_type %#x\n", recv_type);
-			return -1;
+			ret = -1;
+			goto exit_restore_skb;
 		}
 		break;
 	case MWIFIEX_USB_EP_DATA:
-- 
2.25.1