[PATCH AUTOSEL 4.9 03/33] ar5523: Fix null-ptr-deref with unexpected WDCMSG_TARGET_START reply

[PATCH AUTOSEL 4.9 03/33] ar5523: Fix null-ptr-deref with unexpected WDCMSG_TARGET_START reply

[Sasha Levin]

From: Zekun Shen <bruceshenzk@gmail.com>

[ Upstream commit ae80b6033834342601e99f74f6a62ff5092b1cee ]

Unexpected WDCMSG_TARGET_START replay can lead to null-ptr-deref
when ar->tx_cmd->odata is NULL. The patch adds a null check to
prevent such case.

KASAN: null-ptr-deref in range [0x0000000000000000-0x0000000000000007]
 ar5523_cmd+0x46a/0x581 [ar5523]
 ar5523_probe.cold+0x1b7/0x18da [ar5523]
 ? ar5523_cmd_rx_cb+0x7a0/0x7a0 [ar5523]
 ? __pm_runtime_set_status+0x54a/0x8f0
 ? _raw_spin_trylock_bh+0x120/0x120
 ? pm_runtime_barrier+0x220/0x220
 ? __pm_runtime_resume+0xb1/0xf0
 usb_probe_interface+0x25b/0x710
 really_probe+0x209/0x5d0
 driver_probe_device+0xc6/0x1b0
 device_driver_attach+0xe2/0x120

I found the bug using a custome USBFuzz port. It's a research work
to fuzz USB stack/drivers. I modified it to fuzz ath9k driver only,
providing hand-crafted usb descriptors to QEMU.

After fixing the code (fourth byte in usb packet) to WDCMSG_TARGET_START,
I got the null-ptr-deref bug. I believe the bug is triggerable whenever
cmd->odata is NULL. After patching, I tested with the same input and no
longer see the KASAN report.

This was NOT tested on a real device.

Signed-off-by: Zekun Shen <bruceshenzk@gmail.com>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>
Link: https://lore.kernel.org/r/YXsmPQ3awHFLuAj2@10-18-43-117.dynapool.wireless.nyu.edu
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/net/wireless/ath/ar5523/ar5523.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/drivers/net/wireless/ath/ar5523/ar5523.c b/drivers/net/wireless/ath/ar5523/ar5523.c
index 9f4ee1d125b68..0c6b33c464cd9 100644
--- a/drivers/net/wireless/ath/ar5523/ar5523.c
+++ b/drivers/net/wireless/ath/ar5523/ar5523.c
@@ -153,6 +153,10 @@ static void ar5523_cmd_rx_cb(struct urb *urb)
 			ar5523_err(ar, "Invalid reply to WDCMSG_TARGET_START");
 			return;
 		}
+		if (!cmd->odata) {
+			ar5523_err(ar, "Unexpected WDCMSG_TARGET_START reply");
+			return;
+		}
 		memcpy(cmd->odata, hdr + 1, sizeof(u32));
 		cmd->olen = sizeof(u32);
 		cmd->res = 0;
-- 
2.34.1

[PATCH AUTOSEL 4.9 10/33] mwifiex: Fix skb_over_panic in mwifiex_usb_recv()

[Sasha Levin]

From: Zekun Shen <bruceshenzk@gmail.com>

[ 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@nyu.edu>
Signed-off-by: Zekun Shen <bruceshenzk@gmail.com>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>
Link: https://lore.kernel.org/r/YX4CqjfRcTa6bVL+@Zekuns-MBP-16.fios-router.home
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 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 2c4225e57c396..3a26add665ca0 100644
--- a/drivers/net/wireless/marvell/mwifiex/usb.c
+++ b/drivers/net/wireless/marvell/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