[PATCH 4.9 07/20] NFC: port100: fix use-after-free in port100_send_complete

Greg Kroah-Hartman
2022-03-14T11:36:22Z

From: Pavel Skripkin <paskripkin@gmail.com>

[ Upstream commit f80cfe2f26581f188429c12bd937eb905ad3ac7b ]

Syzbot reported UAF in port100_send_complete(). The root case is in
missing usb_kill_urb() calls on error handling path of ->probe function.

port100_send_complete() accesses devm allocated memory which will be
freed on probe failure. We should kill this urbs before returning an
error from probe function to prevent reported use-after-free

Fail log:

BUG: KASAN: use-after-free in port100_send_complete+0x16e/0x1a0 drivers/nfc/port100.c:935
Read of size 1 at addr ffff88801bb59540 by task ksoftirqd/2/26
...
Call Trace:
<TASK>
__dump_stack lib/dump_stack.c:88 [inline]
dump_stack_lvl+0xcd/0x134 lib/dump_stack.c:106
print_address_description.constprop.0.cold+0x8d/0x303 mm/kasan/report.c:255
__kasan_report mm/kasan/report.c:442 [inline]
kasan_report.cold+0x83/0xdf mm/kasan/report.c:459
port100_send_complete+0x16e/0x1a0 drivers/nfc/port100.c:935
__usb_hcd_giveback_urb+0x2b0/0x5c0 drivers/usb/core/hcd.c:1670

...

Allocated by task 1255:
kasan_save_stack+0x1e/0x40 mm/kasan/common.c:38
kasan_set_track mm/kasan/common.c:45 [inline]
set_alloc_info mm/kasan/common.c:436 [inline]
____kasan_kmalloc mm/kasan/common.c:515 [inline]
____kasan_kmalloc mm/kasan/common.c:474 [inline]
__kasan_kmalloc+0xa6/0xd0 mm/kasan/common.c:524
alloc_dr drivers/base/devres.c:116 [inline]
devm_kmalloc+0x96/0x1d0 drivers/base/devres.c:823
devm_kzalloc include/linux/device.h:209 [inline]
port100_probe+0x8a/0x1320 drivers/nfc/port100.c:1502

Freed by task 1255:
kasan_save_stack+0x1e/0x40 mm/kasan/common.c:38
kasan_set_track+0x21/0x30 mm/kasan/common.c:45
kasan_set_free_info+0x20/0x30 mm/kasan/generic.c:370
____kasan_slab_free mm/kasan/common.c:366 [inline]
____kasan_slab_free+0xff/0x140 mm/kasan/common.c:328
kasan_slab_free include/linux/kasan.h:236 [inline]
__cache_free mm/slab.c:3437 [inline]
kfree+0xf8/0x2b0 mm/slab.c:3794
release_nodes+0x112/0x1a0 drivers/base/devres.c:501
devres_release_all+0x114/0x190 drivers/base/devres.c:530
really_probe+0x626/0xcc0 drivers/base/dd.c:670

Reported-and-tested-by: syzbot+16bcb127fb73baeecb14@syzkaller.appspotmail.com
Fixes: 0347a6ab300a ("NFC: port100: Commands mechanism implementation")
Signed-off-by: Pavel Skripkin <paskripkin@gmail.com>
Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@canonical.com>
Link: https://lore.kernel.org/r/20220308185007.6987-1-paskripkin@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/nfc/port100.c | 2 ++
1 file changed, 2 insertions(+)

diff --git a/drivers/nfc/port100.c b/drivers/nfc/port100.c
index ed65993aae96..838ec17073fd 100644
--- a/drivers/nfc/port100.c
+++ b/drivers/nfc/port100.c
@@ -1617,7 +1617,9 @@ static int port100_probe(struct usb_interface *interface,
nfc_digital_free_device(dev->nfc_digital_dev);

error:
+ usb_kill_urb(dev->in_urb);
usb_free_urb(dev->in_urb);
+ usb_kill_urb(dev->out_urb);
usb_free_urb(dev->out_urb);
usb_put_dev(dev->udev);

--
2.34.1