[PATCH AUTOSEL 4.4 08/29] mwifiex: Fix skb_over_panic in mwifiex_usb_recv()

[Sasha Levin]

From: Zekun Shen <bruceshenzk@xxxxxxxxx>

[ Upstream commit 04d80663f67ccef893061b49ec8a42ff7045ae84 ]

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: Brendan Dolan-Gavitt <brendandg@xxxxxxx>
Signed-off-by: Zekun Shen <bruceshenzk@xxxxxxxxx>
Signed-off-by: Kalle Valo <kvalo@xxxxxxxxxxxxxx>
Link: https://lore.kernel.org/r/YX4CqjfRcTa6bVL+@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
 drivers/net/wireless/mwifiex/usb.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/net/wireless/mwifiex/usb.c b/drivers/net/wireless/mwifiex/usb.c
index 1be7b219cb202..4cdf6450aeedd 100644
--- a/drivers/net/wireless/mwifiex/usb.c
+++ b/drivers/net/wireless/mwifiex/usb.c
@@ -132,7 +132,8 @@ 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:
-- 
2.34.1