releases/4.14.7/dvb_frontend-don-t-use-after-free-the-frontend-struct.patch

   1 From b1cb7372fa822af6c06c8045963571d13ad6348b Mon Sep 17 00:00:00 2001
   2 From: Mauro Carvalho Chehab <mchehab@s-opensource.com>
   3 Date: Tue, 7 Nov 2017 08:39:39 -0500
   4 Subject: dvb_frontend: don't use-after-free the frontend struct
   5
   6 From: Mauro Carvalho Chehab <mchehab@s-opensource.com>
   7
   8 commit b1cb7372fa822af6c06c8045963571d13ad6348b upstream.
   9
  10 dvb_frontend_invoke_release() may free the frontend struct.
  11 So, the free logic can't update it anymore after calling it.
  12
  13 That's OK, as __dvb_frontend_free() is called only when the
  14 krefs are zeroed, so nobody is using it anymore.
  15
  16 That should fix the following KASAN error:
  17
  18 The KASAN report looks like this (running on kernel 3e0cc09a3a2c40ec1ffb6b4e12da86e98feccb11 (4.14-rc5+)):
  19 ==================================================================
  20 BUG: KASAN: use-after-free in __dvb_frontend_free+0x113/0x120
  21 Write of size 8 at addr ffff880067d45a00 by task kworker/0:1/24
  22
  23 CPU: 0 PID: 24 Comm: kworker/0:1 Not tainted 4.14.0-rc5-43687-g06ab8a23e0e6 #545
  24 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Bochs 01/01/2011
  25 Workqueue: usb_hub_wq hub_event
  26 Call Trace:
  27  __dump_stack lib/dump_stack.c:16
  28  dump_stack+0x292/0x395 lib/dump_stack.c:52
  29  print_address_description+0x78/0x280 mm/kasan/report.c:252
  30  kasan_report_error mm/kasan/report.c:351
  31  kasan_report+0x23d/0x350 mm/kasan/report.c:409
  32  __asan_report_store8_noabort+0x1c/0x20 mm/kasan/report.c:435
  33  __dvb_frontend_free+0x113/0x120 drivers/media/dvb-core/dvb_frontend.c:156
  34  dvb_frontend_put+0x59/0x70 drivers/media/dvb-core/dvb_frontend.c:176
  35  dvb_frontend_detach+0x120/0x150 drivers/media/dvb-core/dvb_frontend.c:2803
  36  dvb_usb_adapter_frontend_exit+0xd6/0x160 drivers/media/usb/dvb-usb/dvb-usb-dvb.c:340
  37  dvb_usb_adapter_exit drivers/media/usb/dvb-usb/dvb-usb-init.c:116
  38  dvb_usb_exit+0x9b/0x200 drivers/media/usb/dvb-usb/dvb-usb-init.c:132
  39  dvb_usb_device_exit+0xa5/0xf0 drivers/media/usb/dvb-usb/dvb-usb-init.c:295
  40  usb_unbind_interface+0x21c/0xa90 drivers/usb/core/driver.c:423
  41  __device_release_driver drivers/base/dd.c:861
  42  device_release_driver_internal+0x4f1/0x5c0 drivers/base/dd.c:893
  43  device_release_driver+0x1e/0x30 drivers/base/dd.c:918
  44  bus_remove_device+0x2f4/0x4b0 drivers/base/bus.c:565
  45  device_del+0x5c4/0xab0 drivers/base/core.c:1985
  46  usb_disable_device+0x1e9/0x680 drivers/usb/core/message.c:1170
  47  usb_disconnect+0x260/0x7a0 drivers/usb/core/hub.c:2124
  48  hub_port_connect drivers/usb/core/hub.c:4754
  49  hub_port_connect_change drivers/usb/core/hub.c:5009
  50  port_event drivers/usb/core/hub.c:5115
  51  hub_event+0x1318/0x3740 drivers/usb/core/hub.c:5195
  52  process_one_work+0xc73/0x1d90 kernel/workqueue.c:2119
  53  worker_thread+0x221/0x1850 kernel/workqueue.c:2253
  54  kthread+0x363/0x440 kernel/kthread.c:231
  55  ret_from_fork+0x2a/0x40 arch/x86/entry/entry_64.S:431
  56
  57 Allocated by task 24:
  58  save_stack_trace+0x1b/0x20 arch/x86/kernel/stacktrace.c:59
  59  save_stack+0x43/0xd0 mm/kasan/kasan.c:447
  60  set_track mm/kasan/kasan.c:459
  61  kasan_kmalloc+0xad/0xe0 mm/kasan/kasan.c:551
  62  kmem_cache_alloc_trace+0x11e/0x2d0 mm/slub.c:2772
  63  kmalloc ./include/linux/slab.h:493
  64  kzalloc ./include/linux/slab.h:666
  65  dtt200u_fe_attach+0x4c/0x110 drivers/media/usb/dvb-usb/dtt200u-fe.c:212
  66  dtt200u_frontend_attach+0x35/0x80 drivers/media/usb/dvb-usb/dtt200u.c:136
  67  dvb_usb_adapter_frontend_init+0x32b/0x660 drivers/media/usb/dvb-usb/dvb-usb-dvb.c:286
  68  dvb_usb_adapter_init drivers/media/usb/dvb-usb/dvb-usb-init.c:86
  69  dvb_usb_init drivers/media/usb/dvb-usb/dvb-usb-init.c:162
  70  dvb_usb_device_init+0xf73/0x17f0 drivers/media/usb/dvb-usb/dvb-usb-init.c:277
  71  dtt200u_usb_probe+0xa1/0xe0 drivers/media/usb/dvb-usb/dtt200u.c:155
  72  usb_probe_interface+0x35d/0x8e0 drivers/usb/core/driver.c:361
  73  really_probe drivers/base/dd.c:413
  74  driver_probe_device+0x610/0xa00 drivers/base/dd.c:557
  75  __device_attach_driver+0x230/0x290 drivers/base/dd.c:653
  76  bus_for_each_drv+0x161/0x210 drivers/base/bus.c:463
  77  __device_attach+0x26b/0x3c0 drivers/base/dd.c:710
  78  device_initial_probe+0x1f/0x30 drivers/base/dd.c:757
  79  bus_probe_device+0x1eb/0x290 drivers/base/bus.c:523
  80  device_add+0xd0b/0x1660 drivers/base/core.c:1835
  81  usb_set_configuration+0x104e/0x1870 drivers/usb/core/message.c:1932
  82  generic_probe+0x73/0xe0 drivers/usb/core/generic.c:174
  83  usb_probe_device+0xaf/0xe0 drivers/usb/core/driver.c:266
  84  really_probe drivers/base/dd.c:413
  85  driver_probe_device+0x610/0xa00 drivers/base/dd.c:557
  86  __device_attach_driver+0x230/0x290 drivers/base/dd.c:653
  87  bus_for_each_drv+0x161/0x210 drivers/base/bus.c:463
  88  __device_attach+0x26b/0x3c0 drivers/base/dd.c:710
  89  device_initial_probe+0x1f/0x30 drivers/base/dd.c:757
  90  bus_probe_device+0x1eb/0x290 drivers/base/bus.c:523
  91  device_add+0xd0b/0x1660 drivers/base/core.c:1835
  92  usb_new_device+0x7b8/0x1020 drivers/usb/core/hub.c:2457
  93  hub_port_connect drivers/usb/core/hub.c:4903
  94  hub_port_connect_change drivers/usb/core/hub.c:5009
  95  port_event drivers/usb/core/hub.c:5115
  96  hub_event+0x194d/0x3740 drivers/usb/core/hub.c:5195
  97  process_one_work+0xc73/0x1d90 kernel/workqueue.c:2119
  98  worker_thread+0x221/0x1850 kernel/workqueue.c:2253
  99  kthread+0x363/0x440 kernel/kthread.c:231
 100  ret_from_fork+0x2a/0x40 arch/x86/entry/entry_64.S:431
 101
 102 Freed by task 24:
 103  save_stack_trace+0x1b/0x20 arch/x86/kernel/stacktrace.c:59
 104  save_stack+0x43/0xd0 mm/kasan/kasan.c:447
 105  set_track mm/kasan/kasan.c:459
 106  kasan_slab_free+0x72/0xc0 mm/kasan/kasan.c:524
 107  slab_free_hook mm/slub.c:1390
 108  slab_free_freelist_hook mm/slub.c:1412
 109  slab_free mm/slub.c:2988
 110  kfree+0xf6/0x2f0 mm/slub.c:3919
 111  dtt200u_fe_release+0x3c/0x50 drivers/media/usb/dvb-usb/dtt200u-fe.c:202
 112  dvb_frontend_invoke_release.part.13+0x1c/0x30 drivers/media/dvb-core/dvb_frontend.c:2790
 113  dvb_frontend_invoke_release drivers/media/dvb-core/dvb_frontend.c:2789
 114  __dvb_frontend_free+0xad/0x120 drivers/media/dvb-core/dvb_frontend.c:153
 115  dvb_frontend_put+0x59/0x70 drivers/media/dvb-core/dvb_frontend.c:176
 116  dvb_frontend_detach+0x120/0x150 drivers/media/dvb-core/dvb_frontend.c:2803
 117  dvb_usb_adapter_frontend_exit+0xd6/0x160 drivers/media/usb/dvb-usb/dvb-usb-dvb.c:340
 118  dvb_usb_adapter_exit drivers/media/usb/dvb-usb/dvb-usb-init.c:116
 119  dvb_usb_exit+0x9b/0x200 drivers/media/usb/dvb-usb/dvb-usb-init.c:132
 120  dvb_usb_device_exit+0xa5/0xf0 drivers/media/usb/dvb-usb/dvb-usb-init.c:295
 121  usb_unbind_interface+0x21c/0xa90 drivers/usb/core/driver.c:423
 122  __device_release_driver drivers/base/dd.c:861
 123  device_release_driver_internal+0x4f1/0x5c0 drivers/base/dd.c:893
 124  device_release_driver+0x1e/0x30 drivers/base/dd.c:918
 125  bus_remove_device+0x2f4/0x4b0 drivers/base/bus.c:565
 126  device_del+0x5c4/0xab0 drivers/base/core.c:1985
 127  usb_disable_device+0x1e9/0x680 drivers/usb/core/message.c:1170
 128  usb_disconnect+0x260/0x7a0 drivers/usb/core/hub.c:2124
 129  hub_port_connect drivers/usb/core/hub.c:4754
 130  hub_port_connect_change drivers/usb/core/hub.c:5009
 131  port_event drivers/usb/core/hub.c:5115
 132  hub_event+0x1318/0x3740 drivers/usb/core/hub.c:5195
 133  process_one_work+0xc73/0x1d90 kernel/workqueue.c:2119
 134  worker_thread+0x221/0x1850 kernel/workqueue.c:2253
 135  kthread+0x363/0x440 kernel/kthread.c:231
 136  ret_from_fork+0x2a/0x40 arch/x86/entry/entry_64.S:431
 137
 138 The buggy address belongs to the object at ffff880067d45500
 139  which belongs to the cache kmalloc-2048 of size 2048
 140 The buggy address is located 1280 bytes inside of
 141  2048-byte region [ffff880067d45500, ffff880067d45d00)
 142 The buggy address belongs to the page:
 143 page:ffffea00019f5000 count:1 mapcount:0 mapping:          (null)
 144 index:0x0 compound_mapcount: 0
 145 flags: 0x100000000008100(slab|head)
 146 raw: 0100000000008100 0000000000000000 0000000000000000 00000001000f000f
 147 raw: dead000000000100 dead000000000200 ffff88006c002d80 0000000000000000
 148 page dumped because: kasan: bad access detected
 149
 150 Memory state around the buggy address:
 151  ffff880067d45900: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 152  ffff880067d45980: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 153  ffff880067d45a00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 154                    ^
 155  ffff880067d45a80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 156  ffff880067d45b00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 157 ==================================================================
 158
 159 Fixes: ead666000a5f ("media: dvb_frontend: only use kref after initialized")
 160
 161 Reported-by: Andrey Konovalov <andreyknvl@google.com>
 162 Suggested-by: Matthias Schwarzott <zzam@gentoo.org>
 163 Tested-by: Andrey Konovalov <andreyknvl@google.com>
 164 Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
 165 Cc: Guenter Roeck <linux@roeck-us.net>
 166 Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
 167
 168 ---
 169  drivers/media/dvb-core/dvb_frontend.c |    7 ++-----
 170  1 file changed, 2 insertions(+), 5 deletions(-)
 171
 172 --- a/drivers/media/dvb-core/dvb_frontend.c
 173 +++ b/drivers/media/dvb-core/dvb_frontend.c
 174 @@ -150,11 +150,8 @@ static void __dvb_frontend_free(struct d
 175
 176         dvb_frontend_invoke_release(fe, fe->ops.release);
 177
 178 -       if (!fepriv)
 179 -               return;
 180 -
 181 -       kfree(fepriv);
 182 -       fe->frontend_priv = NULL;
 183 +       if (fepriv)
 184 +               kfree(fepriv);
 185  }
 186
 187  static void dvb_frontend_free(struct kref *ref)