From:   Fedor Pchelkin <pchelkin@ispras.ru>
To:     Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Cc:     Fedor Pchelkin <pchelkin@ispras.ru>,
        Jakub Kicinski <kuba@kernel.org>,
        "David S. Miller" <davem@davemloft.net>,
        Minsuk Kang <linuxlovemin@yonsei.ac.kr>,
        Alexey Khoroshilov <khoroshilov@ispras.ru>,
        netdev@vger.kernel.org, linux-kernel@vger.kernel.org,
        lvc-project@linuxtesting.org,
        syzbot+1e608ba4217c96d1952f@syzkaller.appspotmail.com
Subject: [PATCH] nfc: pn533: initialize struct pn533_out_arg properly
Date:   Tue,  7 Mar 2023 00:48:38 +0300
Message-Id: <20230306214838.237801-1-pchelkin@ispras.ru>
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit
Precedence: bulk

struct pn533_out_arg used as a temporary context for out_urb is not
initialized properly. Its uninitialized 'phy' field can be dereferenced in
error cases inside pn533_out_complete() callback function. It causes the
following failure:

general protection fault, probably for non-canonical address 0xdffffc0000000000: 0000 [#1] PREEMPT SMP KASAN
KASAN: null-ptr-deref in range [0x0000000000000000-0x0000000000000007]
CPU: 1 PID: 0 Comm: swapper/1 Not tainted 6.2.0-rc3-next-20230110-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/26/2022
RIP: 0010:pn533_out_complete.cold+0x15/0x44 drivers/nfc/pn533/usb.c:441
Call Trace:
 <IRQ>
 __usb_hcd_giveback_urb+0x2b6/0x5c0 drivers/usb/core/hcd.c:1671
 usb_hcd_giveback_urb+0x384/0x430 drivers/usb/core/hcd.c:1754
 dummy_timer+0x1203/0x32d0 drivers/usb/gadget/udc/dummy_hcd.c:1988
 call_timer_fn+0x1da/0x800 kernel/time/timer.c:1700
 expire_timers+0x234/0x330 kernel/time/timer.c:1751
 __run_timers kernel/time/timer.c:2022 [inline]
 __run_timers kernel/time/timer.c:1995 [inline]
 run_timer_softirq+0x326/0x910 kernel/time/timer.c:2035
 __do_softirq+0x1fb/0xaf6 kernel/softirq.c:571
 invoke_softirq kernel/softirq.c:445 [inline]
 __irq_exit_rcu+0x123/0x180 kernel/softirq.c:650
 irq_exit_rcu+0x9/0x20 kernel/softirq.c:662
 sysvec_apic_timer_interrupt+0x97/0xc0 arch/x86/kernel/apic/apic.c:1107

Initialize the field with the pn533_usb_phy currently used.

Fixes: 9dab880d675b ("nfc: pn533: Wait for out_urb's completion in pn533_usb_send_frame()")
Reported-by: syzbot+1e608ba4217c96d1952f@syzkaller.appspotmail.com
Signed-off-by: Fedor Pchelkin <pchelkin@ispras.ru>
---
 drivers/nfc/pn533/usb.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/nfc/pn533/usb.c b/drivers/nfc/pn533/usb.c
index ed9c5e2cf3ad..159b331b3bf6 100644
--- a/drivers/nfc/pn533/usb.c
+++ b/drivers/nfc/pn533/usb.c
@@ -162,7 +162,7 @@ static int pn533_usb_send_frame(struct pn533 *dev,
 				struct sk_buff *out)
 {
 	struct pn533_usb_phy *phy = dev->phy;
-	struct pn533_out_arg arg;
+	struct pn533_out_arg arg = {.phy = phy};
 	void *cntx;
 	int rc;
 
-- 
2.34.1