Re: [RFT] [media] siano: FIX use-after-free in worker_thread

From: Andrey Konovalov
Date: Wed Sep 27 2017 - 08:00:39 EST


On Wed, Sep 27, 2017 at 11:21 AM, Arvind Yadav
<arvind.yadav.cs@xxxxxxxxx> wrote:
> If CONFIG_MEDIA_CONTROLLER_DVB is enable, We are not releasing
> media device and memory on any failure or disconnect a device.
>
> Adding structure media_device 'mdev' as part of 'smsusb_device_t'
> structure to make proper handle for media device.
> Now releasing a media device and memory on failure. It's allocate
> first in siano_media_device_register() and it should be freed last
> in smsusb_disconnect().
>
> Signed-off-by: Arvind Yadav <arvind.yadav.cs@xxxxxxxxx>

Hi Arvind,

I've tried your patch and still see a crash.

Thanks!

gadgetfs: bound to dummy_udc driver
usb 1-1: new full-speed USB device number 2 using dummy_hcd
gadgetfs: connected
gadgetfs: disconnected
gadgetfs: connected
usb 1-1: config 189 interface 0 altsetting 0 endpoint 0x9 has an
invalid bInterval 0, changing to 4
usb 1-1: New USB device found, idVendor=187f, idProduct=0100
usb 1-1: New USB device strings: Mfr=0, Product=0, SerialNumber=0
gadgetfs: configuration #189
smsusb:smsusb_probe: board id=1, interface number 0
smsusb:siano_media_device_register: media controller created
smsusb:smsusb1_detectmode: product string not found
smsmdtv:smscore_set_device_mode: return error code -22.
smsmdtv:smscore_start_device: set device mode failed , rc -22
smsusb:smsusb_init_device: smscore_start_device(...) failed
smsusb:smsusb_onresponse: error, urb status -2, 0 bytes
smsusb:smsusb_onresponse: error, urb status -71, 0 bytes
smsusb:smsusb_onresponse: error, urb status -71, 0 bytes
smsusb:smsusb_onresponse: error, urb status -71, 0 bytes
smsusb:smsusb_onresponse: error, urb status -71, 0 bytes
smsusb:smsusb_onresponse: error, urb status -71, 0 bytes
smsusb:smsusb_onresponse: error, urb status -71, 0 bytes
smsusb:smsusb_onresponse: error, urb status -71, 0 bytes
smsusb:smsusb_onresponse: error, urb status -71, 0 bytes
smsusb:smsusb_onresponse: error, urb status -71, 0 bytes
smsusb:smsusb_probe: Device initialized with return code -22
==================================================================
BUG: KASAN: use-after-free in worker_thread+0x1468/0x1850
Read of size 8 at addr ffff88006a2b80f0 by task kworker/0:1/24

CPU: 0 PID: 24 Comm: kworker/0:1 Not tainted
4.14.0-rc2-42660-g24b7bd59eec0-dirty #273
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Bochs 01/01/2011
Call Trace:
__dump_stack lib/dump_stack.c:16
dump_stack+0x292/0x395 lib/dump_stack.c:52
print_address_description+0x78/0x280 mm/kasan/report.c:252
kasan_report_error mm/kasan/report.c:351
kasan_report+0x23d/0x350 mm/kasan/report.c:409
__asan_report_load8_noabort+0x19/0x20 mm/kasan/report.c:430
worker_thread+0x1468/0x1850 kernel/workqueue.c:2251
kthread+0x3a1/0x470 kernel/kthread.c:231
ret_from_fork+0x2a/0x40 arch/x86/entry/entry_64.S:431

Allocated by task 1846:
save_stack_trace+0x1b/0x20 arch/x86/kernel/stacktrace.c:59
save_stack+0x43/0xd0 mm/kasan/kasan.c:447
set_track mm/kasan/kasan.c:459
kasan_kmalloc+0xad/0xe0 mm/kasan/kasan.c:551
kmem_cache_alloc_trace+0x11e/0x2d0 mm/slub.c:2772
kmalloc ./include/linux/slab.h:493
kzalloc ./include/linux/slab.h:666
smsusb_init_device+0xd5/0xe40 drivers/media/usb/siano/smsusb.c:418
smsusb_probe+0x4f5/0xdc0 drivers/media/usb/siano/smsusb.c:580
usb_probe_interface+0x35d/0x8e0 drivers/usb/core/driver.c:361
really_probe drivers/base/dd.c:413
driver_probe_device+0x610/0xa00 drivers/base/dd.c:557
__device_attach_driver+0x230/0x290 drivers/base/dd.c:653
bus_for_each_drv+0x161/0x210 drivers/base/bus.c:463
__device_attach+0x26e/0x3d0 drivers/base/dd.c:710
device_initial_probe+0x1f/0x30 drivers/base/dd.c:757
bus_probe_device+0x1eb/0x290 drivers/base/bus.c:523
device_add+0xd0b/0x1660 drivers/base/core.c:1835
usb_set_configuration+0x104e/0x1870 drivers/usb/core/message.c:1932
generic_probe+0x73/0xe0 drivers/usb/core/generic.c:174
usb_probe_device+0xaf/0xe0 drivers/usb/core/driver.c:266
really_probe drivers/base/dd.c:413
driver_probe_device+0x610/0xa00 drivers/base/dd.c:557
__device_attach_driver+0x230/0x290 drivers/base/dd.c:653
bus_for_each_drv+0x161/0x210 drivers/base/bus.c:463
__device_attach+0x26e/0x3d0 drivers/base/dd.c:710
device_initial_probe+0x1f/0x30 drivers/base/dd.c:757
bus_probe_device+0x1eb/0x290 drivers/base/bus.c:523
device_add+0xd0b/0x1660 drivers/base/core.c:1835
usb_new_device+0x7b8/0x1020 drivers/usb/core/hub.c:2457
hub_port_connect drivers/usb/core/hub.c:4903
hub_port_connect_change drivers/usb/core/hub.c:5009
port_event drivers/usb/core/hub.c:5115
hub_event+0x194d/0x3740 drivers/usb/core/hub.c:5195
process_one_work+0xc7f/0x1db0 kernel/workqueue.c:2119
worker_thread+0x221/0x1850 kernel/workqueue.c:2253
kthread+0x3a1/0x470 kernel/kthread.c:231
ret_from_fork+0x2a/0x40 arch/x86/entry/entry_64.S:431

Freed by task 1846:
save_stack_trace+0x1b/0x20 arch/x86/kernel/stacktrace.c:59
save_stack+0x43/0xd0 mm/kasan/kasan.c:447
set_track mm/kasan/kasan.c:459
kasan_slab_free+0x72/0xc0 mm/kasan/kasan.c:524
slab_free_hook mm/slub.c:1390
slab_free_freelist_hook mm/slub.c:1412
slab_free mm/slub.c:2988
kfree+0xf6/0x2f0 mm/slub.c:3919
smsusb_term_device+0x166/0x1f0 drivers/media/usb/siano/smsusb.c:373
smsusb_init_device+0xcaa/0xe40 drivers/media/usb/siano/smsusb.c:505
smsusb_probe+0x4f5/0xdc0 drivers/media/usb/siano/smsusb.c:580
usb_probe_interface+0x35d/0x8e0 drivers/usb/core/driver.c:361
really_probe drivers/base/dd.c:413
driver_probe_device+0x610/0xa00 drivers/base/dd.c:557
__device_attach_driver+0x230/0x290 drivers/base/dd.c:653
bus_for_each_drv+0x161/0x210 drivers/base/bus.c:463
__device_attach+0x26e/0x3d0 drivers/base/dd.c:710
device_initial_probe+0x1f/0x30 drivers/base/dd.c:757
bus_probe_device+0x1eb/0x290 drivers/base/bus.c:523
device_add+0xd0b/0x1660 drivers/base/core.c:1835
usb_set_configuration+0x104e/0x1870 drivers/usb/core/message.c:1932
generic_probe+0x73/0xe0 drivers/usb/core/generic.c:174
usb_probe_device+0xaf/0xe0 drivers/usb/core/driver.c:266
really_probe drivers/base/dd.c:413
driver_probe_device+0x610/0xa00 drivers/base/dd.c:557
__device_attach_driver+0x230/0x290 drivers/base/dd.c:653
bus_for_each_drv+0x161/0x210 drivers/base/bus.c:463
__device_attach+0x26e/0x3d0 drivers/base/dd.c:710
device_initial_probe+0x1f/0x30 drivers/base/dd.c:757
bus_probe_device+0x1eb/0x290 drivers/base/bus.c:523
device_add+0xd0b/0x1660 drivers/base/core.c:1835
usb_new_device+0x7b8/0x1020 drivers/usb/core/hub.c:2457
hub_port_connect drivers/usb/core/hub.c:4903
hub_port_connect_change drivers/usb/core/hub.c:5009
port_event drivers/usb/core/hub.c:5115
hub_event+0x194d/0x3740 drivers/usb/core/hub.c:5195
process_one_work+0xc7f/0x1db0 kernel/workqueue.c:2119
worker_thread+0x221/0x1850 kernel/workqueue.c:2253
kthread+0x3a1/0x470 kernel/kthread.c:231
ret_from_fork+0x2a/0x40 arch/x86/entry/entry_64.S:431

The buggy address belongs to the object at ffff88006a2b8000
which belongs to the cache kmalloc-4096 of size 4096
The buggy address is located 240 bytes inside of
4096-byte region [ffff88006a2b8000, ffff88006a2b9000)
The buggy address belongs to the page:
page:ffffea0001a8ae00 count:1 mapcount:0 mapping: (null)
index:0x0 compound_mapcount: 0
flags: 0x100000000008100(slab|head)
raw: 0100000000008100 0000000000000000 0000000000000000 0000000180070007
raw: dead000000000100 dead000000000200 ffff88006c402c00 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
ffff88006a2b7f80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
ffff88006a2b8000: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff88006a2b8080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
^
ffff88006a2b8100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff88006a2b8180: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================

> ---
> This bug report by Andrey Konovalov "usb/media/smsusb: use-after-free in
> worker_thread".
>
> drivers/media/usb/siano/smsusb.c | 45 ++++++++++++++++++++++++----------------
> 1 file changed, 27 insertions(+), 18 deletions(-)
>
> diff --git a/drivers/media/usb/siano/smsusb.c b/drivers/media/usb/siano/smsusb.c
> index 8c1f926..66936b3 100644
> --- a/drivers/media/usb/siano/smsusb.c
> +++ b/drivers/media/usb/siano/smsusb.c
> @@ -69,6 +69,9 @@ struct smsusb_device_t {
> unsigned char in_ep;
> unsigned char out_ep;
> enum smsusb_state state;
> +#ifdef CONFIG_MEDIA_CONTROLLER_DVB
> + struct media_device *mdev;
> +#endif
> };
>
> static int smsusb_submit_urb(struct smsusb_device_t *dev,
> @@ -359,6 +362,13 @@ static void smsusb_term_device(struct usb_interface *intf)
> if (dev->coredev)
> smscore_unregister_device(dev->coredev);
>
> +#ifdef CONFIG_MEDIA_CONTROLLER_DVB
> + if (dev->mdev) {
> + media_device_unregister(dev->mdev);
> + media_device_cleanup(dev->mdev);
> + kfree(dev->mdev);
> + }
> +#endif
> pr_debug("device 0x%p destroyed\n", dev);
> kfree(dev);
> }
> @@ -370,27 +380,28 @@ static void *siano_media_device_register(struct smsusb_device_t *dev,
> int board_id)
> {
> #ifdef CONFIG_MEDIA_CONTROLLER_DVB
> - struct media_device *mdev;
> struct usb_device *udev = dev->udev;
> struct sms_board *board = sms_get_board(board_id);
> int ret;
>
> - mdev = kzalloc(sizeof(*mdev), GFP_KERNEL);
> - if (!mdev)
> + dev->mdev = kzalloc(sizeof(*dev->mdev), GFP_KERNEL);
> + if (!dev->mdev)
> return NULL;
>
> - media_device_usb_init(mdev, udev, board->name);
>
> - ret = media_device_register(mdev);
> + media_device_usb_init(dev->mdev, udev, board->name);
> +
> + ret = media_device_register(dev->mdev);
> if (ret) {
> - media_device_cleanup(mdev);
> - kfree(mdev);
> + media_device_cleanup(dev->mdev);
> + kfree(dev->mdev);
> + dev->mdev = NULL;
> return NULL;
> }
>
> pr_info("media controller created\n");
>
> - return mdev;
> + return dev->mdev;
> #else
> return NULL;
> #endif
> @@ -458,12 +469,7 @@ static int smsusb_init_device(struct usb_interface *intf, int board_id)
> rc = smscore_register_device(&params, &dev->coredev, mdev);
> if (rc < 0) {
> pr_err("smscore_register_device(...) failed, rc %d\n", rc);
> - smsusb_term_device(intf);
> -#ifdef CONFIG_MEDIA_CONTROLLER_DVB
> - media_device_unregister(mdev);
> -#endif
> - kfree(mdev);
> - return rc;
> + goto err_smsusb_init;
> }
>
> smscore_set_board_id(dev->coredev, board_id);
> @@ -480,8 +486,7 @@ static int smsusb_init_device(struct usb_interface *intf, int board_id)
> rc = smsusb_start_streaming(dev);
> if (rc < 0) {
> pr_err("smsusb_start_streaming(...) failed\n");
> - smsusb_term_device(intf);
> - return rc;
> + goto err_smsusb_init;
> }
>
> dev->state = SMSUSB_ACTIVE;
> @@ -489,13 +494,17 @@ static int smsusb_init_device(struct usb_interface *intf, int board_id)
> rc = smscore_start_device(dev->coredev);
> if (rc < 0) {
> pr_err("smscore_start_device(...) failed\n");
> - smsusb_term_device(intf);
> - return rc;
> + goto err_smsusb_init;
> }
>
> pr_debug("device 0x%p created\n", dev);
>
> return rc;
> +
> +err_smsusb_init:
> + smsusb_term_device(intf);
> +
> + return rc;
> }
>
> static int smsusb_probe(struct usb_interface *intf,
> --
> 1.9.1
>
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