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authorMauro Carvalho Chehab <mchehab@s-opensource.com>2017-11-07 08:39:39 -0500
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2017-12-17 15:08:01 +0100
commit7bc8eb30f1e02b4dd6fd2869720c64d9bf39d765 (patch)
tree6074afbd85d086ef5b31796f1fd4e5cd969b9b56
parentce344631dc13717314184ebd47f5e8b0ff3cfcab (diff)
dvb_frontend: don't use-after-free the frontend struct
commit b1cb7372fa822af6c06c8045963571d13ad6348b upstream. dvb_frontend_invoke_release() may free the frontend struct. So, the free logic can't update it anymore after calling it. That's OK, as __dvb_frontend_free() is called only when the krefs are zeroed, so nobody is using it anymore. That should fix the following KASAN error: The KASAN report looks like this (running on kernel 3e0cc09a3a2c40ec1ffb6b4e12da86e98feccb11 (4.14-rc5+)): ================================================================== 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 Allocated by task 24: 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 dtt200u_fe_attach+0x4c/0x110 drivers/media/usb/dvb-usb/dtt200u-fe.c:212 dtt200u_frontend_attach+0x35/0x80 drivers/media/usb/dvb-usb/dtt200u.c:136 dvb_usb_adapter_frontend_init+0x32b/0x660 drivers/media/usb/dvb-usb/dvb-usb-dvb.c:286 dvb_usb_adapter_init drivers/media/usb/dvb-usb/dvb-usb-init.c:86 dvb_usb_init drivers/media/usb/dvb-usb/dvb-usb-init.c:162 dvb_usb_device_init+0xf73/0x17f0 drivers/media/usb/dvb-usb/dvb-usb-init.c:277 dtt200u_usb_probe+0xa1/0xe0 drivers/media/usb/dvb-usb/dtt200u.c:155 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+0x26b/0x3c0 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+0x26b/0x3c0 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+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 Freed by task 24: 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 dtt200u_fe_release+0x3c/0x50 drivers/media/usb/dvb-usb/dtt200u-fe.c:202 dvb_frontend_invoke_release.part.13+0x1c/0x30 drivers/media/dvb-core/dvb_frontend.c:2790 dvb_frontend_invoke_release drivers/media/dvb-core/dvb_frontend.c:2789 __dvb_frontend_free+0xad/0x120 drivers/media/dvb-core/dvb_frontend.c:153 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 The buggy address belongs to the object at ffff880067d45500 which belongs to the cache kmalloc-2048 of size 2048 The buggy address is located 1280 bytes inside of 2048-byte region [ffff880067d45500, ffff880067d45d00) The buggy address belongs to the page: page:ffffea00019f5000 count:1 mapcount:0 mapping: (null) index:0x0 compound_mapcount: 0 flags: 0x100000000008100(slab|head) raw: 0100000000008100 0000000000000000 0000000000000000 00000001000f000f raw: dead000000000100 dead000000000200 ffff88006c002d80 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff880067d45900: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff880067d45980: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff880067d45a00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff880067d45a80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff880067d45b00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ================================================================== Fixes: ead666000a5f ("media: dvb_frontend: only use kref after initialized") Reported-by: Andrey Konovalov <andreyknvl@google.com> Suggested-by: Matthias Schwarzott <zzam@gentoo.org> Tested-by: Andrey Konovalov <andreyknvl@google.com> Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com> Cc: Guenter Roeck <linux@roeck-us.net> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
-rw-r--r--drivers/media/dvb-core/dvb_frontend.c7
1 files changed, 2 insertions, 5 deletions
diff --git a/drivers/media/dvb-core/dvb_frontend.c b/drivers/media/dvb-core/dvb_frontend.c
index 0a8234846699..33d844fe2e70 100644
--- a/drivers/media/dvb-core/dvb_frontend.c
+++ b/drivers/media/dvb-core/dvb_frontend.c
@@ -150,11 +150,8 @@ static void __dvb_frontend_free(struct dvb_frontend *fe)
dvb_frontend_invoke_release(fe, fe->ops.release);
- if (!fepriv)
- return;
-
- kfree(fepriv);
- fe->frontend_priv = NULL;
+ if (fepriv)
+ kfree(fepriv);
}
static void dvb_frontend_free(struct kref *ref)