| Message ID | c4ad7f4e-c838-aa44-5f0d-f8072ed41904@gentoo.org (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On Mon, Oct 23, 2017 at 8:58 PM, Matthias Schwarzott <zzam@gentoo.org> wrote: > Am 23.10.2017 um 16:41 schrieb Andrey Konovalov: >> Hi! >> >> I've got the following report while fuzzing the kernel with syzkaller. >> >> On commit 3e0cc09a3a2c40ec1ffb6b4e12da86e98feccb11 (4.14-rc5+). >> >> dvb-usb: found a 'WideView WT-220U PenType Receiver (based on ZL353)' >> in warm state. >> dvb-usb: bulk message failed: -22 (2/1102416563) >> dvb-usb: will use the device's hardware PID filter (table count: 15). >> dvbdev: DVB: registering new adapter (WideView WT-220U PenType >> Receiver (based on ZL353)) >> usb 1-1: media controller created >> dvbdev: dvb_create_media_entity: media entity 'dvb-demux' registered. >> usb 1-1: DVB: registering adapter 0 frontend 0 (WideView USB DVB-T)... >> dvbdev: dvb_create_media_entity: media entity 'WideView USB DVB-T' registered. >> Registered IR keymap rc-dtt200u >> rc rc1: IR-receiver inside an USB DVB receiver as >> /devices/platform/dummy_hcd.0/usb1/1-1/rc/rc1 >> input: IR-receiver inside an USB DVB receiver as >> /devices/platform/dummy_hcd.0/usb1/1-1/rc/rc1/input9 >> dvb-usb: schedule remote query interval to 300 msecs. >> dvb-usb: WideView WT-220U PenType Receiver (based on ZL353) >> successfully initialized and connected. >> dvb-usb: bulk message failed: -22 (1/1807119384) >> dvb-usb: error -22 while querying for an remote control event. >> dvb-usb: bulk message failed: -22 (1/1807119384) >> dvb-usb: error -22 while querying for an remote control event. >> dvb-usb: bulk message failed: -22 (1/1807119384) >> dvb-usb: error -22 while querying for an remote control event. >> dvb-usb: bulk message failed: -22 (1/1807119384) >> dvb-usb: error -22 while querying for an remote control event. >> dvb-usb: bulk message failed: -22 (1/1807119384) >> dvb-usb: error -22 while querying for an remote control event. >> dvb-usb: bulk message failed: -22 (1/1807119384) >> dvb-usb: error -22 while querying for an remote control event. >> usb 1-1: USB disconnect, device number 2 >> ================================================================== >> BUG: KASAN: use-after-free in __dvb_frontend_free+0x113/0x120 >> Write of size 8 at addr ffff880067d45a00 by task kworker/0:1/24 >> >> CPU: 0 PID: 24 Comm: kworker/0:1 Not tainted 4.14.0-rc5-43687-g06ab8a23e0e6 #545 >> Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Bochs 01/01/2011 >> Workqueue: usb_hub_wq hub_event >> 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_store8_noabort+0x1c/0x20 mm/kasan/report.c:435 >> __dvb_frontend_free+0x113/0x120 drivers/media/dvb-core/dvb_frontend.c:156 >> dvb_frontend_put+0x59/0x70 drivers/media/dvb-core/dvb_frontend.c:176 >> dvb_frontend_detach+0x120/0x150 drivers/media/dvb-core/dvb_frontend.c:2803 >> dvb_usb_adapter_frontend_exit+0xd6/0x160 >> drivers/media/usb/dvb-usb/dvb-usb-dvb.c:340 >> dvb_usb_adapter_exit drivers/media/usb/dvb-usb/dvb-usb-init.c:116 >> dvb_usb_exit+0x9b/0x200 drivers/media/usb/dvb-usb/dvb-usb-init.c:132 >> dvb_usb_device_exit+0xa5/0xf0 drivers/media/usb/dvb-usb/dvb-usb-init.c:295 >> usb_unbind_interface+0x21c/0xa90 drivers/usb/core/driver.c:423 >> __device_release_driver drivers/base/dd.c:861 >> device_release_driver_internal+0x4f1/0x5c0 drivers/base/dd.c:893 >> device_release_driver+0x1e/0x30 drivers/base/dd.c:918 >> bus_remove_device+0x2f4/0x4b0 drivers/base/bus.c:565 >> device_del+0x5c4/0xab0 drivers/base/core.c:1985 >> usb_disable_device+0x1e9/0x680 drivers/usb/core/message.c:1170 >> usb_disconnect+0x260/0x7a0 drivers/usb/core/hub.c:2124 >> hub_port_connect drivers/usb/core/hub.c:4754 >> hub_port_connect_change drivers/usb/core/hub.c:5009 >> port_event drivers/usb/core/hub.c:5115 >> hub_event+0x1318/0x3740 drivers/usb/core/hub.c:5195 >> process_one_work+0xc73/0x1d90 kernel/workqueue.c:2119 >> worker_thread+0x221/0x1850 kernel/workqueue.c:2253 >> kthread+0x363/0x440 kernel/kthread.c:231 >> ret_from_fork+0x2a/0x40 arch/x86/entry/entry_64.S:431 >> > It looks like this is caused by commit > ead666000a5fe34bdc82d61838e4df2d416ea15e ("media: dvb_frontend: only use > kref after initialized"). > > The writing to "fe->frontend_priv" in dvb_frontend.c:156 is a > use-after-free in case the object dvb_frontend *fe is already freed by > the release callback called in line 153. > Only if the demod driver is based on new style i2c_client the memory is > still accessible. > > There are two possible solutions: > 1. Clear fe->frontend_priv earlier (before line 153). > 2. Do not clear fe->frontend_priv > > Can you try if the following patch (solution 1) fixes the issue? Hi Matthias, Your patch fixes the issue. Thanks! Tested-by: Andrey Konovalov <andreyknvl@google.com> > > Regards > Matthias > > diff --git a/drivers/media/dvb-core/dvb_frontend.c > b/drivers/media/dvb-core/dvb_frontend.c > index daaf969719e4..f552acdb7d8c 100644 > --- a/drivers/media/dvb-core/dvb_frontend.c > +++ b/drivers/media/dvb-core/dvb_frontend.c > @@ -150,10 +150,11 @@ static void __dvb_frontend_free(struct > dvb_frontend *fe) > > dvb_free_device(fepriv->dvbdev); > > + fe->frontend_priv = NULL; > + > dvb_frontend_invoke_release(fe, fe->ops.release); > > kfree(fepriv); > - fe->frontend_priv = NULL; > } > > static void dvb_frontend_free(struct kref *ref)
diff --git a/drivers/media/dvb-core/dvb_frontend.c b/drivers/media/dvb-core/dvb_frontend.c index daaf969719e4..f552acdb7d8c 100644 --- a/drivers/media/dvb-core/dvb_frontend.c +++ b/drivers/media/dvb-core/dvb_frontend.c @@ -150,10 +150,11 @@ static void __dvb_frontend_free(struct dvb_frontend *fe) dvb_free_device(fepriv->dvbdev); + fe->frontend_priv = NULL; + dvb_frontend_invoke_release(fe, fe->ops.release); kfree(fepriv); - fe->frontend_priv = NULL; }