| Message ID | 20240428015834.2485653-1-iam@sung-woo.kim |
|---|---|
| State | Superseded |
| Headers | show |
| Series | [v2] Bluetooth: msft: fix slab-use-after-free in msft_do_close() | expand |
Hi Sungwoo, On Sat, Apr 27, 2024 at 10:03 PM Sungwoo Kim <iam@sung-woo.kim> wrote: > > Hi, could you review this patch? > Now *not static* msft functions hold and put hdev->msft_data. > It prevents from potential and real use-after-free bugs. > > How msft is used after freed: > > [use] > msft_do_close() > msft = hdev->msft_data; > if (!msft) ...(1) <- passed. > return; > mutex_lock(&msft->filter_lock); ...(4) <- used after freed. > > [free] > msft_unregister() > msft = hdev->msft_data; > hdev->msft_data = NULL; ...(2) > kfree(msft); ...(3) <- msft is freed. > > ================================================================== > BUG: KASAN: slab-use-after-free in __mutex_lock_common kernel/locking/mutex.c:587 [inline] > BUG: KASAN: slab-use-after-free in __mutex_lock+0x8f/0xc30 kernel/locking/mutex.c:752 > Read of size 8 at addr ffff888106cbbca8 by task kworker/u5:2/309 > > CPU: 0 PID: 309 Comm: kworker/u5:2 Not tainted 6.9.0-rc5+ #5 > Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.15.0-1 04/01/2014 > Workqueue: hci4 hci_error_reset > Call Trace: > <TASK> > __dump_stack lib/dump_stack.c:88 [inline] > dump_stack_lvl+0xcd/0x140 lib/dump_stack.c:114 > print_address_description mm/kasan/report.c:377 [inline] > print_report+0x191/0x560 mm/kasan/report.c:488 > kasan_report+0xe2/0x120 mm/kasan/report.c:601 > __asan_report_load8_noabort+0x18/0x20 mm/kasan/report_generic.c:381 > __mutex_lock_common kernel/locking/mutex.c:587 [inline] > __mutex_lock+0x8f/0xc30 kernel/locking/mutex.c:752 > mutex_lock_nested+0x1f/0x30 kernel/locking/mutex.c:804 > msft_do_close+0x292/0x700 net/bluetooth/msft.c:694 > hci_dev_close_sync+0x906/0xf10 net/bluetooth/hci_sync.c:5168 > hci_dev_do_close net/bluetooth/hci_core.c:554 [inline] > hci_error_reset+0x152/0x410 net/bluetooth/hci_core.c:1091 > process_one_work kernel/workqueue.c:3254 [inline] > process_scheduled_works+0x90f/0x1530 kernel/workqueue.c:3335 > worker_thread+0x926/0xe70 kernel/workqueue.c:3416 > kthread+0x2e3/0x380 kernel/kthread.c:388 > ret_from_fork+0x5c/0x90 arch/x86/kernel/process.c:147 > ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244 > </TASK> > > Allocated by task 7328: > kasan_save_stack mm/kasan/common.c:47 [inline] > kasan_save_track+0x30/0x70 mm/kasan/common.c:68 > kasan_save_alloc_info+0x3c/0x50 mm/kasan/generic.c:565 > poison_kmalloc_redzone mm/kasan/common.c:370 [inline] > __kasan_kmalloc+0xa2/0xc0 mm/kasan/common.c:387 > kasan_kmalloc include/linux/kasan.h:211 [inline] > kmalloc_trace+0x20c/0x3e0 mm/slub.c:3997 > kmalloc include/linux/slab.h:628 [inline] > kzalloc include/linux/slab.h:749 [inline] > msft_register+0x66/0x1d0 net/bluetooth/msft.c:760 > hci_register_dev+0x85e/0x9a0 net/bluetooth/hci_core.c:2737 > __vhci_create_device drivers/bluetooth/hci_vhci.c:438 [inline] > vhci_create_device+0x390/0x720 drivers/bluetooth/hci_vhci.c:480 > vhci_get_user drivers/bluetooth/hci_vhci.c:537 [inline] > vhci_write+0x39b/0x460 drivers/bluetooth/hci_vhci.c:617 > call_write_iter include/linux/fs.h:2110 [inline] > new_sync_write fs/read_write.c:497 [inline] > vfs_write+0x8eb/0xb50 fs/read_write.c:590 > ksys_write+0x106/0x1f0 fs/read_write.c:643 > __do_sys_write fs/read_write.c:655 [inline] > __se_sys_write fs/read_write.c:652 [inline] > __x64_sys_write+0x84/0xa0 fs/read_write.c:652 > x64_sys_call+0x271a/0x2ce0 arch/x86/include/generated/asm/syscalls_64.h:2 > do_syscall_x64 arch/x86/entry/common.c:52 [inline] > do_syscall_64+0x9c/0x130 arch/x86/entry/common.c:83 > entry_SYSCALL_64_after_hwframe+0x76/0x7e > > Freed by task 7332: > kasan_save_stack mm/kasan/common.c:47 [inline] > kasan_save_track+0x30/0x70 mm/kasan/common.c:68 > kasan_save_free_info+0x44/0x50 mm/kasan/generic.c:579 > poison_slab_object+0x11a/0x190 mm/kasan/common.c:240 > __kasan_slab_free+0x3b/0x60 mm/kasan/common.c:256 > kasan_slab_free include/linux/kasan.h:184 [inline] > slab_free_hook mm/slub.c:2106 [inline] > slab_free mm/slub.c:4280 [inline] > kfree+0x13c/0x330 mm/slub.c:4390 > msft_unregister+0x9d/0x120 net/bluetooth/msft.c:785 > hci_unregister_dev+0x1d9/0x520 net/bluetooth/hci_core.c:2771 > vhci_release+0x8c/0xe0 drivers/bluetooth/hci_vhci.c:674 > __fput+0x36f/0x750 fs/file_table.c:422 > ____fput+0x1e/0x30 fs/file_table.c:450 > task_work_run+0x1da/0x280 kernel/task_work.c:180 > exit_task_work include/linux/task_work.h:38 [inline] > do_exit+0x856/0x2210 kernel/exit.c:878 > do_group_exit+0x201/0x2c0 kernel/exit.c:1027 > get_signal+0x12ff/0x1380 kernel/signal.c:2911 > arch_do_signal_or_restart+0x3b/0x650 arch/x86/kernel/signal.c:310 > exit_to_user_mode_loop kernel/entry/common.c:111 [inline] > exit_to_user_mode_prepare include/linux/entry-common.h:328 [inline] > __syscall_exit_to_user_mode_work kernel/entry/common.c:207 [inline] > syscall_exit_to_user_mode+0xcc/0x2a0 kernel/entry/common.c:218 > do_syscall_64+0xa8/0x130 arch/x86/entry/common.c:89 > entry_SYSCALL_64_after_hwframe+0x76/0x7e > > The buggy address belongs to the object at ffff888106cbbc00 > which belongs to the cache kmalloc-256 of size 256 > The buggy address is located 168 bytes inside of > freed 256-byte region [ffff888106cbbc00, ffff888106cbbd00) > > The buggy address belongs to the physical page: > page: refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x106cba > head: order:1 entire_mapcount:0 nr_pages_mapped:0 pincount:0 > flags: 0x17ffffe0000840(slab|head|node=0|zone=2|lastcpupid=0x3fffff) > page_type: 0xffffffff() > raw: 0017ffffe0000840 ffff888100042040 ffffea00042de590 ffffea00041b3e10 > raw: 0000000000000000 00000000000a000a 00000001ffffffff 0000000000000000 > head: 0017ffffe0000840 ffff888100042040 ffffea00042de590 ffffea00041b3e10 > head: 0000000000000000 00000000000a000a 00000001ffffffff 0000000000000000 > head: 0017ffffe0000001 ffffea00041b2e81 dead000000000122 00000000ffffffff > head: 0000000200000000 0000000000000000 00000000ffffffff 0000000000000000 > page dumped because: kasan: bad access detected > > Memory state around the buggy address: > ffff888106cbbb80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc > ffff888106cbbc00: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb > >ffff888106cbbc80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb > ^ > ffff888106cbbd00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc > ffff888106cbbd80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc > ================================================================== > > Fixes: 9e14606d8f38 ("Bluetooth: disable advertisement filters during suspend") > Signed-off-by: Sungwoo Kim <iam@sung-woo.kim> > --- > v2: Move BT_DBG after null checking in msft_data_hold_unless_zero() > > net/bluetooth/msft.c | 124 ++++++++++++++++++++++++++++++++++--------- > 1 file changed, 99 insertions(+), 25 deletions(-) > > diff --git a/net/bluetooth/msft.c b/net/bluetooth/msft.c > index 9612c5d1b..1f79e7980 100644 > --- a/net/bluetooth/msft.c > +++ b/net/bluetooth/msft.c > @@ -132,10 +132,45 @@ struct msft_data { > __u8 filter_enabled; > /* To synchronize add/remove address filter and monitor device event.*/ > struct mutex filter_lock; > + struct kref kref; NAK, the lifetime of this object should be tied to hdev which already has a kref. > }; > > +static void msft_data_free(struct kref *kref); > + > +static struct msft_data *msft_data_hold_unless_zero(struct msft_data *msft) > +{ > + if (!msft) > + return NULL; > + > + BT_DBG("msft %p orig refcnt %u", msft, kref_read(&msft->kref)); > + > + if (!kref_get_unless_zero(&msft->kref)) > + return NULL; > + > + return msft; > +} > + > +static void msft_data_put(struct msft_data *msft) > +{ > + BT_DBG("msft %p orig refcnt %u", msft, kref_read(&msft->kref)); > + > + kref_put(&msft->kref, msft_data_free); > +} > + > +static void msft_data_free(struct kref *kref) > +{ > + struct msft_data *msft = container_of(kref, struct msft_data, kref); > + > + BT_DBG("msft %p", msft); > + > + kfree(msft->evt_prefix); > + mutex_destroy(&msft->filter_lock); > + kfree(msft); > +} > + > bool msft_monitor_supported(struct hci_dev *hdev) > { > + /* msft_get_features() holds and put hdev->msft_data */ > return !!(msft_get_features(hdev) & MSFT_FEATURE_MASK_LE_ADV_MONITOR); > } > > @@ -449,12 +484,17 @@ static int msft_remove_monitor_sync(struct hci_dev *hdev, > /* This function requires the caller holds hci_req_sync_lock */ > int msft_suspend_sync(struct hci_dev *hdev) > { > - struct msft_data *msft = hdev->msft_data; > + struct msft_data *msft; > struct adv_monitor *monitor; > int handle = 0; > > - if (!msft || !msft_monitor_supported(hdev)) > + msft = msft_data_hold_unless_zero(hdev->msft_data); > + if (!msft) > return 0; > + if (!msft_monitor_supported(hdev)) { > + msft_data_put(msft); > + return 0; > + } > > msft->suspending = true; > > @@ -471,6 +511,7 @@ int msft_suspend_sync(struct hci_dev *hdev) > /* All monitors have been removed */ > msft->suspending = false; > > + msft_data_put(msft); > return 0; > } > > @@ -608,11 +649,17 @@ static void reregister_monitor(struct hci_dev *hdev) > /* This function requires the caller holds hci_req_sync_lock */ > int msft_resume_sync(struct hci_dev *hdev) > { > - struct msft_data *msft = hdev->msft_data; > + struct msft_data *msft; > > - if (!msft || !msft_monitor_supported(hdev)) > + msft = msft_data_hold_unless_zero(hdev->msft_data); > + if (!msft) > return 0; > > + if (!msft_monitor_supported(hdev)) { > + msft_data_put(msft); > + return 0; > + } > + > hci_dev_lock(hdev); > > /* Clear already tracked devices on resume. Once the monitors are > @@ -625,17 +672,19 @@ int msft_resume_sync(struct hci_dev *hdev) > > reregister_monitor(hdev); > > + msft_data_put(msft); > return 0; > } > > /* This function requires the caller holds hci_req_sync_lock */ > void msft_do_open(struct hci_dev *hdev) > { > - struct msft_data *msft = hdev->msft_data; > + struct msft_data *msft; > > if (hdev->msft_opcode == HCI_OP_NOP) > return; > > + msft = msft_data_hold_unless_zero(hdev->msft_data); > if (!msft) { > bt_dev_err(hdev, "MSFT extension not registered"); > return; > @@ -650,8 +699,7 @@ void msft_do_open(struct hci_dev *hdev) > msft->features = 0; > > if (!read_supported_features(hdev, msft)) { > - hdev->msft_data = NULL; > - kfree(msft); > + msft_data_put(msft); > return; > } > > @@ -663,15 +711,17 @@ void msft_do_open(struct hci_dev *hdev) > */ > reregister_monitor(hdev); > } > + msft_data_put(msft); > } > > void msft_do_close(struct hci_dev *hdev) > { > - struct msft_data *msft = hdev->msft_data; > + struct msft_data *msft; > struct msft_monitor_advertisement_handle_data *handle_data, *tmp; > struct msft_monitor_addr_filter_data *address_filter, *n; > struct adv_monitor *monitor; > > + msft = msft_data_hold_unless_zero(hdev->msft_data); > if (!msft) > return; > > @@ -705,6 +755,8 @@ void msft_do_close(struct hci_dev *hdev) > hdev->advmon_pend_notify = false; > msft_monitor_device_del(hdev, 0, NULL, 0, true); > > + msft_data_put(msft); > + > hci_dev_unlock(hdev); > } > > @@ -767,6 +819,7 @@ void msft_register(struct hci_dev *hdev) > INIT_LIST_HEAD(&msft->address_filters); > hdev->msft_data = msft; > mutex_init(&msft->filter_lock); > + kref_init(&msft->kref); > } > > void msft_unregister(struct hci_dev *hdev) > @@ -779,10 +832,7 @@ void msft_unregister(struct hci_dev *hdev) > bt_dev_dbg(hdev, "Unregister MSFT extension"); > > hdev->msft_data = NULL; > - > - kfree(msft->evt_prefix); > - mutex_destroy(&msft->filter_lock); > - kfree(msft); > + msft_data_put(msft); > } > > /* This function requires the caller holds hdev->lock */ > @@ -1068,10 +1118,11 @@ static void msft_monitor_device_evt(struct hci_dev *hdev, struct sk_buff *skb) > > void msft_vendor_evt(struct hci_dev *hdev, void *data, struct sk_buff *skb) > { > - struct msft_data *msft = hdev->msft_data; > + struct msft_data *msft; > u8 *evt_prefix; > u8 *evt; > > + msft = msft_data_hold_unless_zero(hdev->msft_data); > if (!msft) > return; > > @@ -1081,21 +1132,21 @@ void msft_vendor_evt(struct hci_dev *hdev, void *data, struct sk_buff *skb) > if (msft->evt_prefix_len > 0) { > evt_prefix = msft_skb_pull(hdev, skb, 0, msft->evt_prefix_len); > if (!evt_prefix) > - return; > + goto done; > > if (memcmp(evt_prefix, msft->evt_prefix, msft->evt_prefix_len)) > - return; > + goto done; > } > > /* Every event starts at least with an event code and the rest of > * the data is variable and depends on the event code. > */ > if (skb->len < 1) > - return; > + goto done; > > evt = msft_skb_pull(hdev, skb, 0, sizeof(*evt)); > if (!evt) > - return; > + goto done; > > hci_dev_lock(hdev); > > @@ -1112,13 +1163,24 @@ void msft_vendor_evt(struct hci_dev *hdev, void *data, struct sk_buff *skb) > } > > hci_dev_unlock(hdev); > + > +done: > + msft_data_put(msft); > } > > __u64 msft_get_features(struct hci_dev *hdev) > { > - struct msft_data *msft = hdev->msft_data; > + struct msft_data *msft; > + unsigned long long features; > + > + msft = msft_data_hold_unless_zero(hdev->msft_data); > + if (!msft) > + return 0; > + > + features = msft->features; > > - return msft ? msft->features : 0; > + msft_data_put(msft); > + return features; > } > > static void msft_le_set_advertisement_filter_enable_cb(struct hci_dev *hdev, > @@ -1152,37 +1214,48 @@ static void msft_le_set_advertisement_filter_enable_cb(struct hci_dev *hdev, > /* This function requires the caller holds hci_req_sync_lock */ > int msft_add_monitor_pattern(struct hci_dev *hdev, struct adv_monitor *monitor) > { > - struct msft_data *msft = hdev->msft_data; > + struct msft_data *msft; > + int err; > > + msft = msft_data_hold_unless_zero(hdev->msft_data); > if (!msft) > return -EOPNOTSUPP; > > - if (msft->resuming || msft->suspending) > + if (msft->resuming || msft->suspending) { > + msft_data_put(msft); > return -EBUSY; > + } > > - return msft_add_monitor_sync(hdev, monitor); > + err = msft_add_monitor_sync(hdev, monitor); > + msft_data_put(msft); > + return err; > } > > /* This function requires the caller holds hci_req_sync_lock */ > int msft_remove_monitor(struct hci_dev *hdev, struct adv_monitor *monitor) > { > - struct msft_data *msft = hdev->msft_data; > + struct msft_data *msft; > + int err; > > + msft = msft_data_hold_unless_zero(hdev->msft_data); > if (!msft) > return -EOPNOTSUPP; > > if (msft->resuming || msft->suspending) > return -EBUSY; > > - return msft_remove_monitor_sync(hdev, monitor); > + err = msft_remove_monitor_sync(hdev, monitor); > + msft_data_put(msft); > + return err; > } > > int msft_set_filter_enable(struct hci_dev *hdev, bool enable) > { > struct msft_cp_le_set_advertisement_filter_enable cp; > - struct msft_data *msft = hdev->msft_data; > + struct msft_data *msft; > int err; > > + msft = msft_data_hold_unless_zero(hdev->msft_data); > if (!msft) > return -EOPNOTSUPP; > > @@ -1193,6 +1266,7 @@ int msft_set_filter_enable(struct hci_dev *hdev, bool enable) > > msft_le_set_advertisement_filter_enable_cb(hdev, &cp, err); > > + msft_data_put(msft); > return 0; > } > > -- > 2.34.1 Looks at the current code I do wonder if the order is incorrect since we do: msft_unregister(hdev); hci_dev_do_close(hdev); Anyway msft_unregister shall probably be renamed to msft_release and then called from hci_release_dev instead since that is where we free fields of hdev, not on unregister.
Dear Luiz, Thank you for reviewing. On Mon, Apr 29, 2024 at 12:43 PM Luiz Augusto von Dentz <luiz.dentz@gmail.com> wrote: > > Hi Sungwoo, > > On Sat, Apr 27, 2024 at 10:03 PM Sungwoo Kim <iam@sung-woo.kim> wrote: > > > > Hi, could you review this patch? > > Now *not static* msft functions hold and put hdev->msft_data. > > It prevents from potential and real use-after-free bugs. > > > > How msft is used after freed: > > > > [use] > > msft_do_close() > > msft = hdev->msft_data; > > if (!msft) ...(1) <- passed. > > return; > > mutex_lock(&msft->filter_lock); ...(4) <- used after freed. > > > > [free] > > msft_unregister() > > msft = hdev->msft_data; > > hdev->msft_data = NULL; ...(2) > > kfree(msft); ...(3) <- msft is freed. > > > > ================================================================== > > BUG: KASAN: slab-use-after-free in __mutex_lock_common kernel/locking/mutex.c:587 [inline] > > BUG: KASAN: slab-use-after-free in __mutex_lock+0x8f/0xc30 kernel/locking/mutex.c:752 > > Read of size 8 at addr ffff888106cbbca8 by task kworker/u5:2/309 > > > > CPU: 0 PID: 309 Comm: kworker/u5:2 Not tainted 6.9.0-rc5+ #5 > > Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.15.0-1 04/01/2014 > > Workqueue: hci4 hci_error_reset > > Call Trace: > > <TASK> > > __dump_stack lib/dump_stack.c:88 [inline] > > dump_stack_lvl+0xcd/0x140 lib/dump_stack.c:114 > > print_address_description mm/kasan/report.c:377 [inline] > > print_report+0x191/0x560 mm/kasan/report.c:488 > > kasan_report+0xe2/0x120 mm/kasan/report.c:601 > > __asan_report_load8_noabort+0x18/0x20 mm/kasan/report_generic.c:381 > > __mutex_lock_common kernel/locking/mutex.c:587 [inline] > > __mutex_lock+0x8f/0xc30 kernel/locking/mutex.c:752 > > mutex_lock_nested+0x1f/0x30 kernel/locking/mutex.c:804 > > msft_do_close+0x292/0x700 net/bluetooth/msft.c:694 > > hci_dev_close_sync+0x906/0xf10 net/bluetooth/hci_sync.c:5168 > > hci_dev_do_close net/bluetooth/hci_core.c:554 [inline] > > hci_error_reset+0x152/0x410 net/bluetooth/hci_core.c:1091 > > process_one_work kernel/workqueue.c:3254 [inline] > > process_scheduled_works+0x90f/0x1530 kernel/workqueue.c:3335 > > worker_thread+0x926/0xe70 kernel/workqueue.c:3416 > > kthread+0x2e3/0x380 kernel/kthread.c:388 > > ret_from_fork+0x5c/0x90 arch/x86/kernel/process.c:147 > > ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244 > > </TASK> > > > > Allocated by task 7328: > > kasan_save_stack mm/kasan/common.c:47 [inline] > > kasan_save_track+0x30/0x70 mm/kasan/common.c:68 > > kasan_save_alloc_info+0x3c/0x50 mm/kasan/generic.c:565 > > poison_kmalloc_redzone mm/kasan/common.c:370 [inline] > > __kasan_kmalloc+0xa2/0xc0 mm/kasan/common.c:387 > > kasan_kmalloc include/linux/kasan.h:211 [inline] > > kmalloc_trace+0x20c/0x3e0 mm/slub.c:3997 > > kmalloc include/linux/slab.h:628 [inline] > > kzalloc include/linux/slab.h:749 [inline] > > msft_register+0x66/0x1d0 net/bluetooth/msft.c:760 > > hci_register_dev+0x85e/0x9a0 net/bluetooth/hci_core.c:2737 > > __vhci_create_device drivers/bluetooth/hci_vhci.c:438 [inline] > > vhci_create_device+0x390/0x720 drivers/bluetooth/hci_vhci.c:480 > > vhci_get_user drivers/bluetooth/hci_vhci.c:537 [inline] > > vhci_write+0x39b/0x460 drivers/bluetooth/hci_vhci.c:617 > > call_write_iter include/linux/fs.h:2110 [inline] > > new_sync_write fs/read_write.c:497 [inline] > > vfs_write+0x8eb/0xb50 fs/read_write.c:590 > > ksys_write+0x106/0x1f0 fs/read_write.c:643 > > __do_sys_write fs/read_write.c:655 [inline] > > __se_sys_write fs/read_write.c:652 [inline] > > __x64_sys_write+0x84/0xa0 fs/read_write.c:652 > > x64_sys_call+0x271a/0x2ce0 arch/x86/include/generated/asm/syscalls_64.h:2 > > do_syscall_x64 arch/x86/entry/common.c:52 [inline] > > do_syscall_64+0x9c/0x130 arch/x86/entry/common.c:83 > > entry_SYSCALL_64_after_hwframe+0x76/0x7e > > > > Freed by task 7332: > > kasan_save_stack mm/kasan/common.c:47 [inline] > > kasan_save_track+0x30/0x70 mm/kasan/common.c:68 > > kasan_save_free_info+0x44/0x50 mm/kasan/generic.c:579 > > poison_slab_object+0x11a/0x190 mm/kasan/common.c:240 > > __kasan_slab_free+0x3b/0x60 mm/kasan/common.c:256 > > kasan_slab_free include/linux/kasan.h:184 [inline] > > slab_free_hook mm/slub.c:2106 [inline] > > slab_free mm/slub.c:4280 [inline] > > kfree+0x13c/0x330 mm/slub.c:4390 > > msft_unregister+0x9d/0x120 net/bluetooth/msft.c:785 > > hci_unregister_dev+0x1d9/0x520 net/bluetooth/hci_core.c:2771 > > vhci_release+0x8c/0xe0 drivers/bluetooth/hci_vhci.c:674 > > __fput+0x36f/0x750 fs/file_table.c:422 > > ____fput+0x1e/0x30 fs/file_table.c:450 > > task_work_run+0x1da/0x280 kernel/task_work.c:180 > > exit_task_work include/linux/task_work.h:38 [inline] > > do_exit+0x856/0x2210 kernel/exit.c:878 > > do_group_exit+0x201/0x2c0 kernel/exit.c:1027 > > get_signal+0x12ff/0x1380 kernel/signal.c:2911 > > arch_do_signal_or_restart+0x3b/0x650 arch/x86/kernel/signal.c:310 > > exit_to_user_mode_loop kernel/entry/common.c:111 [inline] > > exit_to_user_mode_prepare include/linux/entry-common.h:328 [inline] > > __syscall_exit_to_user_mode_work kernel/entry/common.c:207 [inline] > > syscall_exit_to_user_mode+0xcc/0x2a0 kernel/entry/common.c:218 > > do_syscall_64+0xa8/0x130 arch/x86/entry/common.c:89 > > entry_SYSCALL_64_after_hwframe+0x76/0x7e > > > > The buggy address belongs to the object at ffff888106cbbc00 > > which belongs to the cache kmalloc-256 of size 256 > > The buggy address is located 168 bytes inside of > > freed 256-byte region [ffff888106cbbc00, ffff888106cbbd00) > > > > The buggy address belongs to the physical page: > > page: refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x106cba > > head: order:1 entire_mapcount:0 nr_pages_mapped:0 pincount:0 > > flags: 0x17ffffe0000840(slab|head|node=0|zone=2|lastcpupid=0x3fffff) > > page_type: 0xffffffff() > > raw: 0017ffffe0000840 ffff888100042040 ffffea00042de590 ffffea00041b3e10 > > raw: 0000000000000000 00000000000a000a 00000001ffffffff 0000000000000000 > > head: 0017ffffe0000840 ffff888100042040 ffffea00042de590 ffffea00041b3e10 > > head: 0000000000000000 00000000000a000a 00000001ffffffff 0000000000000000 > > head: 0017ffffe0000001 ffffea00041b2e81 dead000000000122 00000000ffffffff > > head: 0000000200000000 0000000000000000 00000000ffffffff 0000000000000000 > > page dumped because: kasan: bad access detected > > > > Memory state around the buggy address: > > ffff888106cbbb80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc > > ffff888106cbbc00: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb > > >ffff888106cbbc80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb > > ^ > > ffff888106cbbd00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc > > ffff888106cbbd80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc > > ================================================================== > > > > Fixes: 9e14606d8f38 ("Bluetooth: disable advertisement filters during suspend") > > Signed-off-by: Sungwoo Kim <iam@sung-woo.kim> > > --- > > v2: Move BT_DBG after null checking in msft_data_hold_unless_zero() > > > > net/bluetooth/msft.c | 124 ++++++++++++++++++++++++++++++++++--------- > > 1 file changed, 99 insertions(+), 25 deletions(-) > > > > diff --git a/net/bluetooth/msft.c b/net/bluetooth/msft.c > > index 9612c5d1b..1f79e7980 100644 > > --- a/net/bluetooth/msft.c > > +++ b/net/bluetooth/msft.c > > @@ -132,10 +132,45 @@ struct msft_data { > > __u8 filter_enabled; > > /* To synchronize add/remove address filter and monitor device event.*/ > > struct mutex filter_lock; > > + struct kref kref; > > NAK, the lifetime of this object should be tied to hdev which already > has a kref. I got this. > > > }; > > > > +static void msft_data_free(struct kref *kref); > > + > > +static struct msft_data *msft_data_hold_unless_zero(struct msft_data *msft) > > +{ > > + if (!msft) > > + return NULL; > > + > > + BT_DBG("msft %p orig refcnt %u", msft, kref_read(&msft->kref)); > > + > > + if (!kref_get_unless_zero(&msft->kref)) > > + return NULL; > > + > > + return msft; > > +} > > + > > +static void msft_data_put(struct msft_data *msft) > > +{ > > + BT_DBG("msft %p orig refcnt %u", msft, kref_read(&msft->kref)); > > + > > + kref_put(&msft->kref, msft_data_free); > > +} > > + > > +static void msft_data_free(struct kref *kref) > > +{ > > + struct msft_data *msft = container_of(kref, struct msft_data, kref); > > + > > + BT_DBG("msft %p", msft); > > + > > + kfree(msft->evt_prefix); > > + mutex_destroy(&msft->filter_lock); > > + kfree(msft); > > +} > > + > > bool msft_monitor_supported(struct hci_dev *hdev) > > { > > + /* msft_get_features() holds and put hdev->msft_data */ > > return !!(msft_get_features(hdev) & MSFT_FEATURE_MASK_LE_ADV_MONITOR); > > } > > > > @@ -449,12 +484,17 @@ static int msft_remove_monitor_sync(struct hci_dev *hdev, > > /* This function requires the caller holds hci_req_sync_lock */ > > int msft_suspend_sync(struct hci_dev *hdev) > > { > > - struct msft_data *msft = hdev->msft_data; > > + struct msft_data *msft; > > struct adv_monitor *monitor; > > int handle = 0; > > > > - if (!msft || !msft_monitor_supported(hdev)) > > + msft = msft_data_hold_unless_zero(hdev->msft_data); > > + if (!msft) > > return 0; > > + if (!msft_monitor_supported(hdev)) { > > + msft_data_put(msft); > > + return 0; > > + } > > > > msft->suspending = true; > > > > @@ -471,6 +511,7 @@ int msft_suspend_sync(struct hci_dev *hdev) > > /* All monitors have been removed */ > > msft->suspending = false; > > > > + msft_data_put(msft); > > return 0; > > } > > > > @@ -608,11 +649,17 @@ static void reregister_monitor(struct hci_dev *hdev) > > /* This function requires the caller holds hci_req_sync_lock */ > > int msft_resume_sync(struct hci_dev *hdev) > > { > > - struct msft_data *msft = hdev->msft_data; > > + struct msft_data *msft; > > > > - if (!msft || !msft_monitor_supported(hdev)) > > + msft = msft_data_hold_unless_zero(hdev->msft_data); > > + if (!msft) > > return 0; > > > > + if (!msft_monitor_supported(hdev)) { > > + msft_data_put(msft); > > + return 0; > > + } > > + > > hci_dev_lock(hdev); > > > > /* Clear already tracked devices on resume. Once the monitors are > > @@ -625,17 +672,19 @@ int msft_resume_sync(struct hci_dev *hdev) > > > > reregister_monitor(hdev); > > > > + msft_data_put(msft); > > return 0; > > } > > > > /* This function requires the caller holds hci_req_sync_lock */ > > void msft_do_open(struct hci_dev *hdev) > > { > > - struct msft_data *msft = hdev->msft_data; > > + struct msft_data *msft; > > > > if (hdev->msft_opcode == HCI_OP_NOP) > > return; > > > > + msft = msft_data_hold_unless_zero(hdev->msft_data); > > if (!msft) { > > bt_dev_err(hdev, "MSFT extension not registered"); > > return; > > @@ -650,8 +699,7 @@ void msft_do_open(struct hci_dev *hdev) > > msft->features = 0; > > > > if (!read_supported_features(hdev, msft)) { > > - hdev->msft_data = NULL; > > - kfree(msft); > > + msft_data_put(msft); > > return; > > } > > > > @@ -663,15 +711,17 @@ void msft_do_open(struct hci_dev *hdev) > > */ > > reregister_monitor(hdev); > > } > > + msft_data_put(msft); > > } > > > > void msft_do_close(struct hci_dev *hdev) > > { > > - struct msft_data *msft = hdev->msft_data; > > + struct msft_data *msft; > > struct msft_monitor_advertisement_handle_data *handle_data, *tmp; > > struct msft_monitor_addr_filter_data *address_filter, *n; > > struct adv_monitor *monitor; > > > > + msft = msft_data_hold_unless_zero(hdev->msft_data); > > if (!msft) > > return; > > > > @@ -705,6 +755,8 @@ void msft_do_close(struct hci_dev *hdev) > > hdev->advmon_pend_notify = false; > > msft_monitor_device_del(hdev, 0, NULL, 0, true); > > > > + msft_data_put(msft); > > + > > hci_dev_unlock(hdev); > > } > > > > @@ -767,6 +819,7 @@ void msft_register(struct hci_dev *hdev) > > INIT_LIST_HEAD(&msft->address_filters); > > hdev->msft_data = msft; > > mutex_init(&msft->filter_lock); > > + kref_init(&msft->kref); > > } > > > > void msft_unregister(struct hci_dev *hdev) > > @@ -779,10 +832,7 @@ void msft_unregister(struct hci_dev *hdev) > > bt_dev_dbg(hdev, "Unregister MSFT extension"); > > > > hdev->msft_data = NULL; > > - > > - kfree(msft->evt_prefix); > > - mutex_destroy(&msft->filter_lock); > > - kfree(msft); > > + msft_data_put(msft); > > } > > > > /* This function requires the caller holds hdev->lock */ > > @@ -1068,10 +1118,11 @@ static void msft_monitor_device_evt(struct hci_dev *hdev, struct sk_buff *skb) > > > > void msft_vendor_evt(struct hci_dev *hdev, void *data, struct sk_buff *skb) > > { > > - struct msft_data *msft = hdev->msft_data; > > + struct msft_data *msft; > > u8 *evt_prefix; > > u8 *evt; > > > > + msft = msft_data_hold_unless_zero(hdev->msft_data); > > if (!msft) > > return; > > > > @@ -1081,21 +1132,21 @@ void msft_vendor_evt(struct hci_dev *hdev, void *data, struct sk_buff *skb) > > if (msft->evt_prefix_len > 0) { > > evt_prefix = msft_skb_pull(hdev, skb, 0, msft->evt_prefix_len); > > if (!evt_prefix) > > - return; > > + goto done; > > > > if (memcmp(evt_prefix, msft->evt_prefix, msft->evt_prefix_len)) > > - return; > > + goto done; > > } > > > > /* Every event starts at least with an event code and the rest of > > * the data is variable and depends on the event code. > > */ > > if (skb->len < 1) > > - return; > > + goto done; > > > > evt = msft_skb_pull(hdev, skb, 0, sizeof(*evt)); > > if (!evt) > > - return; > > + goto done; > > > > hci_dev_lock(hdev); > > > > @@ -1112,13 +1163,24 @@ void msft_vendor_evt(struct hci_dev *hdev, void *data, struct sk_buff *skb) > > } > > > > hci_dev_unlock(hdev); > > + > > +done: > > + msft_data_put(msft); > > } > > > > __u64 msft_get_features(struct hci_dev *hdev) > > { > > - struct msft_data *msft = hdev->msft_data; > > + struct msft_data *msft; > > + unsigned long long features; > > + > > + msft = msft_data_hold_unless_zero(hdev->msft_data); > > + if (!msft) > > + return 0; > > + > > + features = msft->features; > > > > - return msft ? msft->features : 0; > > + msft_data_put(msft); > > + return features; > > } > > > > static void msft_le_set_advertisement_filter_enable_cb(struct hci_dev *hdev, > > @@ -1152,37 +1214,48 @@ static void msft_le_set_advertisement_filter_enable_cb(struct hci_dev *hdev, > > /* This function requires the caller holds hci_req_sync_lock */ > > int msft_add_monitor_pattern(struct hci_dev *hdev, struct adv_monitor *monitor) > > { > > - struct msft_data *msft = hdev->msft_data; > > + struct msft_data *msft; > > + int err; > > > > + msft = msft_data_hold_unless_zero(hdev->msft_data); > > if (!msft) > > return -EOPNOTSUPP; > > > > - if (msft->resuming || msft->suspending) > > + if (msft->resuming || msft->suspending) { > > + msft_data_put(msft); > > return -EBUSY; > > + } > > > > - return msft_add_monitor_sync(hdev, monitor); > > + err = msft_add_monitor_sync(hdev, monitor); > > + msft_data_put(msft); > > + return err; > > } > > > > /* This function requires the caller holds hci_req_sync_lock */ > > int msft_remove_monitor(struct hci_dev *hdev, struct adv_monitor *monitor) > > { > > - struct msft_data *msft = hdev->msft_data; > > + struct msft_data *msft; > > + int err; > > > > + msft = msft_data_hold_unless_zero(hdev->msft_data); > > if (!msft) > > return -EOPNOTSUPP; > > > > if (msft->resuming || msft->suspending) > > return -EBUSY; > > > > - return msft_remove_monitor_sync(hdev, monitor); > > + err = msft_remove_monitor_sync(hdev, monitor); > > + msft_data_put(msft); > > + return err; > > } > > > > int msft_set_filter_enable(struct hci_dev *hdev, bool enable) > > { > > struct msft_cp_le_set_advertisement_filter_enable cp; > > - struct msft_data *msft = hdev->msft_data; > > + struct msft_data *msft; > > int err; > > > > + msft = msft_data_hold_unless_zero(hdev->msft_data); > > if (!msft) > > return -EOPNOTSUPP; > > > > @@ -1193,6 +1266,7 @@ int msft_set_filter_enable(struct hci_dev *hdev, bool enable) > > > > msft_le_set_advertisement_filter_enable_cb(hdev, &cp, err); > > > > + msft_data_put(msft); > > return 0; > > } > > > > -- > > 2.34.1 > > Looks at the current code I do wonder if the order is incorrect since we do: > > msft_unregister(hdev); > > hci_dev_do_close(hdev); > > Anyway msft_unregister shall probably be renamed to msft_release and It could be a nitpick but how about making msft_unregister() static and wrapping this with msft_release() for consistency? Since msft_register is there, it may look inconsistent if msft_unregister() doesn't exist. > then called from hci_release_dev instead since that is where we free > fields of hdev, not on unregister. > > -- > Luiz Augusto von Dentz > Best, Sungwoo.
Hi Sungwoo, On Mon, Apr 29, 2024 at 6:16 PM Sungwoo Kim <iam@sung-woo.kim> wrote: > > Dear Luiz, > Thank you for reviewing. > > On Mon, Apr 29, 2024 at 12:43 PM Luiz Augusto von Dentz > <luiz.dentz@gmail.com> wrote: > > > > Hi Sungwoo, > > > > On Sat, Apr 27, 2024 at 10:03 PM Sungwoo Kim <iam@sung-woo.kim> wrote: > > > > > > Hi, could you review this patch? > > > Now *not static* msft functions hold and put hdev->msft_data. > > > It prevents from potential and real use-after-free bugs. > > > > > > How msft is used after freed: > > > > > > [use] > > > msft_do_close() > > > msft = hdev->msft_data; > > > if (!msft) ...(1) <- passed. > > > return; > > > mutex_lock(&msft->filter_lock); ...(4) <- used after freed. > > > > > > [free] > > > msft_unregister() > > > msft = hdev->msft_data; > > > hdev->msft_data = NULL; ...(2) > > > kfree(msft); ...(3) <- msft is freed. > > > > > > ================================================================== > > > BUG: KASAN: slab-use-after-free in __mutex_lock_common kernel/locking/mutex.c:587 [inline] > > > BUG: KASAN: slab-use-after-free in __mutex_lock+0x8f/0xc30 kernel/locking/mutex.c:752 > > > Read of size 8 at addr ffff888106cbbca8 by task kworker/u5:2/309 > > > > > > CPU: 0 PID: 309 Comm: kworker/u5:2 Not tainted 6.9.0-rc5+ #5 > > > Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.15.0-1 04/01/2014 > > > Workqueue: hci4 hci_error_reset > > > Call Trace: > > > <TASK> > > > __dump_stack lib/dump_stack.c:88 [inline] > > > dump_stack_lvl+0xcd/0x140 lib/dump_stack.c:114 > > > print_address_description mm/kasan/report.c:377 [inline] > > > print_report+0x191/0x560 mm/kasan/report.c:488 > > > kasan_report+0xe2/0x120 mm/kasan/report.c:601 > > > __asan_report_load8_noabort+0x18/0x20 mm/kasan/report_generic.c:381 > > > __mutex_lock_common kernel/locking/mutex.c:587 [inline] > > > __mutex_lock+0x8f/0xc30 kernel/locking/mutex.c:752 > > > mutex_lock_nested+0x1f/0x30 kernel/locking/mutex.c:804 > > > msft_do_close+0x292/0x700 net/bluetooth/msft.c:694 > > > hci_dev_close_sync+0x906/0xf10 net/bluetooth/hci_sync.c:5168 > > > hci_dev_do_close net/bluetooth/hci_core.c:554 [inline] > > > hci_error_reset+0x152/0x410 net/bluetooth/hci_core.c:1091 > > > process_one_work kernel/workqueue.c:3254 [inline] > > > process_scheduled_works+0x90f/0x1530 kernel/workqueue.c:3335 > > > worker_thread+0x926/0xe70 kernel/workqueue.c:3416 > > > kthread+0x2e3/0x380 kernel/kthread.c:388 > > > ret_from_fork+0x5c/0x90 arch/x86/kernel/process.c:147 > > > ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244 > > > </TASK> > > > > > > Allocated by task 7328: > > > kasan_save_stack mm/kasan/common.c:47 [inline] > > > kasan_save_track+0x30/0x70 mm/kasan/common.c:68 > > > kasan_save_alloc_info+0x3c/0x50 mm/kasan/generic.c:565 > > > poison_kmalloc_redzone mm/kasan/common.c:370 [inline] > > > __kasan_kmalloc+0xa2/0xc0 mm/kasan/common.c:387 > > > kasan_kmalloc include/linux/kasan.h:211 [inline] > > > kmalloc_trace+0x20c/0x3e0 mm/slub.c:3997 > > > kmalloc include/linux/slab.h:628 [inline] > > > kzalloc include/linux/slab.h:749 [inline] > > > msft_register+0x66/0x1d0 net/bluetooth/msft.c:760 > > > hci_register_dev+0x85e/0x9a0 net/bluetooth/hci_core.c:2737 > > > __vhci_create_device drivers/bluetooth/hci_vhci.c:438 [inline] > > > vhci_create_device+0x390/0x720 drivers/bluetooth/hci_vhci.c:480 > > > vhci_get_user drivers/bluetooth/hci_vhci.c:537 [inline] > > > vhci_write+0x39b/0x460 drivers/bluetooth/hci_vhci.c:617 > > > call_write_iter include/linux/fs.h:2110 [inline] > > > new_sync_write fs/read_write.c:497 [inline] > > > vfs_write+0x8eb/0xb50 fs/read_write.c:590 > > > ksys_write+0x106/0x1f0 fs/read_write.c:643 > > > __do_sys_write fs/read_write.c:655 [inline] > > > __se_sys_write fs/read_write.c:652 [inline] > > > __x64_sys_write+0x84/0xa0 fs/read_write.c:652 > > > x64_sys_call+0x271a/0x2ce0 arch/x86/include/generated/asm/syscalls_64.h:2 > > > do_syscall_x64 arch/x86/entry/common.c:52 [inline] > > > do_syscall_64+0x9c/0x130 arch/x86/entry/common.c:83 > > > entry_SYSCALL_64_after_hwframe+0x76/0x7e > > > > > > Freed by task 7332: > > > kasan_save_stack mm/kasan/common.c:47 [inline] > > > kasan_save_track+0x30/0x70 mm/kasan/common.c:68 > > > kasan_save_free_info+0x44/0x50 mm/kasan/generic.c:579 > > > poison_slab_object+0x11a/0x190 mm/kasan/common.c:240 > > > __kasan_slab_free+0x3b/0x60 mm/kasan/common.c:256 > > > kasan_slab_free include/linux/kasan.h:184 [inline] > > > slab_free_hook mm/slub.c:2106 [inline] > > > slab_free mm/slub.c:4280 [inline] > > > kfree+0x13c/0x330 mm/slub.c:4390 > > > msft_unregister+0x9d/0x120 net/bluetooth/msft.c:785 > > > hci_unregister_dev+0x1d9/0x520 net/bluetooth/hci_core.c:2771 > > > vhci_release+0x8c/0xe0 drivers/bluetooth/hci_vhci.c:674 > > > __fput+0x36f/0x750 fs/file_table.c:422 > > > ____fput+0x1e/0x30 fs/file_table.c:450 > > > task_work_run+0x1da/0x280 kernel/task_work.c:180 > > > exit_task_work include/linux/task_work.h:38 [inline] > > > do_exit+0x856/0x2210 kernel/exit.c:878 > > > do_group_exit+0x201/0x2c0 kernel/exit.c:1027 > > > get_signal+0x12ff/0x1380 kernel/signal.c:2911 > > > arch_do_signal_or_restart+0x3b/0x650 arch/x86/kernel/signal.c:310 > > > exit_to_user_mode_loop kernel/entry/common.c:111 [inline] > > > exit_to_user_mode_prepare include/linux/entry-common.h:328 [inline] > > > __syscall_exit_to_user_mode_work kernel/entry/common.c:207 [inline] > > > syscall_exit_to_user_mode+0xcc/0x2a0 kernel/entry/common.c:218 > > > do_syscall_64+0xa8/0x130 arch/x86/entry/common.c:89 > > > entry_SYSCALL_64_after_hwframe+0x76/0x7e > > > > > > The buggy address belongs to the object at ffff888106cbbc00 > > > which belongs to the cache kmalloc-256 of size 256 > > > The buggy address is located 168 bytes inside of > > > freed 256-byte region [ffff888106cbbc00, ffff888106cbbd00) > > > > > > The buggy address belongs to the physical page: > > > page: refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x106cba > > > head: order:1 entire_mapcount:0 nr_pages_mapped:0 pincount:0 > > > flags: 0x17ffffe0000840(slab|head|node=0|zone=2|lastcpupid=0x3fffff) > > > page_type: 0xffffffff() > > > raw: 0017ffffe0000840 ffff888100042040 ffffea00042de590 ffffea00041b3e10 > > > raw: 0000000000000000 00000000000a000a 00000001ffffffff 0000000000000000 > > > head: 0017ffffe0000840 ffff888100042040 ffffea00042de590 ffffea00041b3e10 > > > head: 0000000000000000 00000000000a000a 00000001ffffffff 0000000000000000 > > > head: 0017ffffe0000001 ffffea00041b2e81 dead000000000122 00000000ffffffff > > > head: 0000000200000000 0000000000000000 00000000ffffffff 0000000000000000 > > > page dumped because: kasan: bad access detected > > > > > > Memory state around the buggy address: > > > ffff888106cbbb80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc > > > ffff888106cbbc00: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb > > > >ffff888106cbbc80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb > > > ^ > > > ffff888106cbbd00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc > > > ffff888106cbbd80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc > > > ================================================================== > > > > > > Fixes: 9e14606d8f38 ("Bluetooth: disable advertisement filters during suspend") > > > Signed-off-by: Sungwoo Kim <iam@sung-woo.kim> > > > --- > > > v2: Move BT_DBG after null checking in msft_data_hold_unless_zero() > > > > > > net/bluetooth/msft.c | 124 ++++++++++++++++++++++++++++++++++--------- > > > 1 file changed, 99 insertions(+), 25 deletions(-) > > > > > > diff --git a/net/bluetooth/msft.c b/net/bluetooth/msft.c > > > index 9612c5d1b..1f79e7980 100644 > > > --- a/net/bluetooth/msft.c > > > +++ b/net/bluetooth/msft.c > > > @@ -132,10 +132,45 @@ struct msft_data { > > > __u8 filter_enabled; > > > /* To synchronize add/remove address filter and monitor device event.*/ > > > struct mutex filter_lock; > > > + struct kref kref; > > > > NAK, the lifetime of this object should be tied to hdev which already > > has a kref. > > I got this. > > > > > > }; > > > > > > +static void msft_data_free(struct kref *kref); > > > + > > > +static struct msft_data *msft_data_hold_unless_zero(struct msft_data *msft) > > > +{ > > > + if (!msft) > > > + return NULL; > > > + > > > + BT_DBG("msft %p orig refcnt %u", msft, kref_read(&msft->kref)); > > > + > > > + if (!kref_get_unless_zero(&msft->kref)) > > > + return NULL; > > > + > > > + return msft; > > > +} > > > + > > > +static void msft_data_put(struct msft_data *msft) > > > +{ > > > + BT_DBG("msft %p orig refcnt %u", msft, kref_read(&msft->kref)); > > > + > > > + kref_put(&msft->kref, msft_data_free); > > > +} > > > + > > > +static void msft_data_free(struct kref *kref) > > > +{ > > > + struct msft_data *msft = container_of(kref, struct msft_data, kref); > > > + > > > + BT_DBG("msft %p", msft); > > > + > > > + kfree(msft->evt_prefix); > > > + mutex_destroy(&msft->filter_lock); > > > + kfree(msft); > > > +} > > > + > > > bool msft_monitor_supported(struct hci_dev *hdev) > > > { > > > + /* msft_get_features() holds and put hdev->msft_data */ > > > return !!(msft_get_features(hdev) & MSFT_FEATURE_MASK_LE_ADV_MONITOR); > > > } > > > > > > @@ -449,12 +484,17 @@ static int msft_remove_monitor_sync(struct hci_dev *hdev, > > > /* This function requires the caller holds hci_req_sync_lock */ > > > int msft_suspend_sync(struct hci_dev *hdev) > > > { > > > - struct msft_data *msft = hdev->msft_data; > > > + struct msft_data *msft; > > > struct adv_monitor *monitor; > > > int handle = 0; > > > > > > - if (!msft || !msft_monitor_supported(hdev)) > > > + msft = msft_data_hold_unless_zero(hdev->msft_data); > > > + if (!msft) > > > return 0; > > > + if (!msft_monitor_supported(hdev)) { > > > + msft_data_put(msft); > > > + return 0; > > > + } > > > > > > msft->suspending = true; > > > > > > @@ -471,6 +511,7 @@ int msft_suspend_sync(struct hci_dev *hdev) > > > /* All monitors have been removed */ > > > msft->suspending = false; > > > > > > + msft_data_put(msft); > > > return 0; > > > } > > > > > > @@ -608,11 +649,17 @@ static void reregister_monitor(struct hci_dev *hdev) > > > /* This function requires the caller holds hci_req_sync_lock */ > > > int msft_resume_sync(struct hci_dev *hdev) > > > { > > > - struct msft_data *msft = hdev->msft_data; > > > + struct msft_data *msft; > > > > > > - if (!msft || !msft_monitor_supported(hdev)) > > > + msft = msft_data_hold_unless_zero(hdev->msft_data); > > > + if (!msft) > > > return 0; > > > > > > + if (!msft_monitor_supported(hdev)) { > > > + msft_data_put(msft); > > > + return 0; > > > + } > > > + > > > hci_dev_lock(hdev); > > > > > > /* Clear already tracked devices on resume. Once the monitors are > > > @@ -625,17 +672,19 @@ int msft_resume_sync(struct hci_dev *hdev) > > > > > > reregister_monitor(hdev); > > > > > > + msft_data_put(msft); > > > return 0; > > > } > > > > > > /* This function requires the caller holds hci_req_sync_lock */ > > > void msft_do_open(struct hci_dev *hdev) > > > { > > > - struct msft_data *msft = hdev->msft_data; > > > + struct msft_data *msft; > > > > > > if (hdev->msft_opcode == HCI_OP_NOP) > > > return; > > > > > > + msft = msft_data_hold_unless_zero(hdev->msft_data); > > > if (!msft) { > > > bt_dev_err(hdev, "MSFT extension not registered"); > > > return; > > > @@ -650,8 +699,7 @@ void msft_do_open(struct hci_dev *hdev) > > > msft->features = 0; > > > > > > if (!read_supported_features(hdev, msft)) { > > > - hdev->msft_data = NULL; > > > - kfree(msft); > > > + msft_data_put(msft); > > > return; > > > } > > > > > > @@ -663,15 +711,17 @@ void msft_do_open(struct hci_dev *hdev) > > > */ > > > reregister_monitor(hdev); > > > } > > > + msft_data_put(msft); > > > } > > > > > > void msft_do_close(struct hci_dev *hdev) > > > { > > > - struct msft_data *msft = hdev->msft_data; > > > + struct msft_data *msft; > > > struct msft_monitor_advertisement_handle_data *handle_data, *tmp; > > > struct msft_monitor_addr_filter_data *address_filter, *n; > > > struct adv_monitor *monitor; > > > > > > + msft = msft_data_hold_unless_zero(hdev->msft_data); > > > if (!msft) > > > return; > > > > > > @@ -705,6 +755,8 @@ void msft_do_close(struct hci_dev *hdev) > > > hdev->advmon_pend_notify = false; > > > msft_monitor_device_del(hdev, 0, NULL, 0, true); > > > > > > + msft_data_put(msft); > > > + > > > hci_dev_unlock(hdev); > > > } > > > > > > @@ -767,6 +819,7 @@ void msft_register(struct hci_dev *hdev) > > > INIT_LIST_HEAD(&msft->address_filters); > > > hdev->msft_data = msft; > > > mutex_init(&msft->filter_lock); > > > + kref_init(&msft->kref); > > > } > > > > > > void msft_unregister(struct hci_dev *hdev) > > > @@ -779,10 +832,7 @@ void msft_unregister(struct hci_dev *hdev) > > > bt_dev_dbg(hdev, "Unregister MSFT extension"); > > > > > > hdev->msft_data = NULL; > > > - > > > - kfree(msft->evt_prefix); > > > - mutex_destroy(&msft->filter_lock); > > > - kfree(msft); > > > + msft_data_put(msft); > > > } > > > > > > /* This function requires the caller holds hdev->lock */ > > > @@ -1068,10 +1118,11 @@ static void msft_monitor_device_evt(struct hci_dev *hdev, struct sk_buff *skb) > > > > > > void msft_vendor_evt(struct hci_dev *hdev, void *data, struct sk_buff *skb) > > > { > > > - struct msft_data *msft = hdev->msft_data; > > > + struct msft_data *msft; > > > u8 *evt_prefix; > > > u8 *evt; > > > > > > + msft = msft_data_hold_unless_zero(hdev->msft_data); > > > if (!msft) > > > return; > > > > > > @@ -1081,21 +1132,21 @@ void msft_vendor_evt(struct hci_dev *hdev, void *data, struct sk_buff *skb) > > > if (msft->evt_prefix_len > 0) { > > > evt_prefix = msft_skb_pull(hdev, skb, 0, msft->evt_prefix_len); > > > if (!evt_prefix) > > > - return; > > > + goto done; > > > > > > if (memcmp(evt_prefix, msft->evt_prefix, msft->evt_prefix_len)) > > > - return; > > > + goto done; > > > } > > > > > > /* Every event starts at least with an event code and the rest of > > > * the data is variable and depends on the event code. > > > */ > > > if (skb->len < 1) > > > - return; > > > + goto done; > > > > > > evt = msft_skb_pull(hdev, skb, 0, sizeof(*evt)); > > > if (!evt) > > > - return; > > > + goto done; > > > > > > hci_dev_lock(hdev); > > > > > > @@ -1112,13 +1163,24 @@ void msft_vendor_evt(struct hci_dev *hdev, void *data, struct sk_buff *skb) > > > } > > > > > > hci_dev_unlock(hdev); > > > + > > > +done: > > > + msft_data_put(msft); > > > } > > > > > > __u64 msft_get_features(struct hci_dev *hdev) > > > { > > > - struct msft_data *msft = hdev->msft_data; > > > + struct msft_data *msft; > > > + unsigned long long features; > > > + > > > + msft = msft_data_hold_unless_zero(hdev->msft_data); > > > + if (!msft) > > > + return 0; > > > + > > > + features = msft->features; > > > > > > - return msft ? msft->features : 0; > > > + msft_data_put(msft); > > > + return features; > > > } > > > > > > static void msft_le_set_advertisement_filter_enable_cb(struct hci_dev *hdev, > > > @@ -1152,37 +1214,48 @@ static void msft_le_set_advertisement_filter_enable_cb(struct hci_dev *hdev, > > > /* This function requires the caller holds hci_req_sync_lock */ > > > int msft_add_monitor_pattern(struct hci_dev *hdev, struct adv_monitor *monitor) > > > { > > > - struct msft_data *msft = hdev->msft_data; > > > + struct msft_data *msft; > > > + int err; > > > > > > + msft = msft_data_hold_unless_zero(hdev->msft_data); > > > if (!msft) > > > return -EOPNOTSUPP; > > > > > > - if (msft->resuming || msft->suspending) > > > + if (msft->resuming || msft->suspending) { > > > + msft_data_put(msft); > > > return -EBUSY; > > > + } > > > > > > - return msft_add_monitor_sync(hdev, monitor); > > > + err = msft_add_monitor_sync(hdev, monitor); > > > + msft_data_put(msft); > > > + return err; > > > } > > > > > > /* This function requires the caller holds hci_req_sync_lock */ > > > int msft_remove_monitor(struct hci_dev *hdev, struct adv_monitor *monitor) > > > { > > > - struct msft_data *msft = hdev->msft_data; > > > + struct msft_data *msft; > > > + int err; > > > > > > + msft = msft_data_hold_unless_zero(hdev->msft_data); > > > if (!msft) > > > return -EOPNOTSUPP; > > > > > > if (msft->resuming || msft->suspending) > > > return -EBUSY; > > > > > > - return msft_remove_monitor_sync(hdev, monitor); > > > + err = msft_remove_monitor_sync(hdev, monitor); > > > + msft_data_put(msft); > > > + return err; > > > } > > > > > > int msft_set_filter_enable(struct hci_dev *hdev, bool enable) > > > { > > > struct msft_cp_le_set_advertisement_filter_enable cp; > > > - struct msft_data *msft = hdev->msft_data; > > > + struct msft_data *msft; > > > int err; > > > > > > + msft = msft_data_hold_unless_zero(hdev->msft_data); > > > if (!msft) > > > return -EOPNOTSUPP; > > > > > > @@ -1193,6 +1266,7 @@ int msft_set_filter_enable(struct hci_dev *hdev, bool enable) > > > > > > msft_le_set_advertisement_filter_enable_cb(hdev, &cp, err); > > > > > > + msft_data_put(msft); > > > return 0; > > > } > > > > > > -- > > > 2.34.1 > > > > Looks at the current code I do wonder if the order is incorrect since we do: > > > > msft_unregister(hdev); > > > > hci_dev_do_close(hdev); > > > > Anyway msft_unregister shall probably be renamed to msft_release and > > It could be a nitpick but how about making msft_unregister() static > and wrapping this with msft_release() for consistency? > Since msft_register is there, it may look inconsistent if > msft_unregister() doesn't exist. Consistent with what, if we are to be consistent with hci_release then this shall be called msft_release, hci_unregister acts more like a cleanup function before it is freed, but in case of msft it doesn't seem we need to do any extra cleanups. > > then called from hci_release_dev instead since that is where we free > > fields of hdev, not on unregister. > > > > -- > > Luiz Augusto von Dentz > > > > Best, > Sungwoo.
diff --git a/net/bluetooth/msft.c b/net/bluetooth/msft.c index 9612c5d1b..1f79e7980 100644 --- a/net/bluetooth/msft.c +++ b/net/bluetooth/msft.c @@ -132,10 +132,45 @@ struct msft_data { __u8 filter_enabled; /* To synchronize add/remove address filter and monitor device event.*/ struct mutex filter_lock; + struct kref kref; }; +static void msft_data_free(struct kref *kref); + +static struct msft_data *msft_data_hold_unless_zero(struct msft_data *msft) +{ + if (!msft) + return NULL; + + BT_DBG("msft %p orig refcnt %u", msft, kref_read(&msft->kref)); + + if (!kref_get_unless_zero(&msft->kref)) + return NULL; + + return msft; +} + +static void msft_data_put(struct msft_data *msft) +{ + BT_DBG("msft %p orig refcnt %u", msft, kref_read(&msft->kref)); + + kref_put(&msft->kref, msft_data_free); +} + +static void msft_data_free(struct kref *kref) +{ + struct msft_data *msft = container_of(kref, struct msft_data, kref); + + BT_DBG("msft %p", msft); + + kfree(msft->evt_prefix); + mutex_destroy(&msft->filter_lock); + kfree(msft); +} + bool msft_monitor_supported(struct hci_dev *hdev) { + /* msft_get_features() holds and put hdev->msft_data */ return !!(msft_get_features(hdev) & MSFT_FEATURE_MASK_LE_ADV_MONITOR); } @@ -449,12 +484,17 @@ static int msft_remove_monitor_sync(struct hci_dev *hdev, /* This function requires the caller holds hci_req_sync_lock */ int msft_suspend_sync(struct hci_dev *hdev) { - struct msft_data *msft = hdev->msft_data; + struct msft_data *msft; struct adv_monitor *monitor; int handle = 0; - if (!msft || !msft_monitor_supported(hdev)) + msft = msft_data_hold_unless_zero(hdev->msft_data); + if (!msft) return 0; + if (!msft_monitor_supported(hdev)) { + msft_data_put(msft); + return 0; + } msft->suspending = true; @@ -471,6 +511,7 @@ int msft_suspend_sync(struct hci_dev *hdev) /* All monitors have been removed */ msft->suspending = false; + msft_data_put(msft); return 0; } @@ -608,11 +649,17 @@ static void reregister_monitor(struct hci_dev *hdev) /* This function requires the caller holds hci_req_sync_lock */ int msft_resume_sync(struct hci_dev *hdev) { - struct msft_data *msft = hdev->msft_data; + struct msft_data *msft; - if (!msft || !msft_monitor_supported(hdev)) + msft = msft_data_hold_unless_zero(hdev->msft_data); + if (!msft) return 0; + if (!msft_monitor_supported(hdev)) { + msft_data_put(msft); + return 0; + } + hci_dev_lock(hdev); /* Clear already tracked devices on resume. Once the monitors are @@ -625,17 +672,19 @@ int msft_resume_sync(struct hci_dev *hdev) reregister_monitor(hdev); + msft_data_put(msft); return 0; } /* This function requires the caller holds hci_req_sync_lock */ void msft_do_open(struct hci_dev *hdev) { - struct msft_data *msft = hdev->msft_data; + struct msft_data *msft; if (hdev->msft_opcode == HCI_OP_NOP) return; + msft = msft_data_hold_unless_zero(hdev->msft_data); if (!msft) { bt_dev_err(hdev, "MSFT extension not registered"); return; @@ -650,8 +699,7 @@ void msft_do_open(struct hci_dev *hdev) msft->features = 0; if (!read_supported_features(hdev, msft)) { - hdev->msft_data = NULL; - kfree(msft); + msft_data_put(msft); return; } @@ -663,15 +711,17 @@ void msft_do_open(struct hci_dev *hdev) */ reregister_monitor(hdev); } + msft_data_put(msft); } void msft_do_close(struct hci_dev *hdev) { - struct msft_data *msft = hdev->msft_data; + struct msft_data *msft; struct msft_monitor_advertisement_handle_data *handle_data, *tmp; struct msft_monitor_addr_filter_data *address_filter, *n; struct adv_monitor *monitor; + msft = msft_data_hold_unless_zero(hdev->msft_data); if (!msft) return; @@ -705,6 +755,8 @@ void msft_do_close(struct hci_dev *hdev) hdev->advmon_pend_notify = false; msft_monitor_device_del(hdev, 0, NULL, 0, true); + msft_data_put(msft); + hci_dev_unlock(hdev); } @@ -767,6 +819,7 @@ void msft_register(struct hci_dev *hdev) INIT_LIST_HEAD(&msft->address_filters); hdev->msft_data = msft; mutex_init(&msft->filter_lock); + kref_init(&msft->kref); } void msft_unregister(struct hci_dev *hdev) @@ -779,10 +832,7 @@ void msft_unregister(struct hci_dev *hdev) bt_dev_dbg(hdev, "Unregister MSFT extension"); hdev->msft_data = NULL; - - kfree(msft->evt_prefix); - mutex_destroy(&msft->filter_lock); - kfree(msft); + msft_data_put(msft); } /* This function requires the caller holds hdev->lock */ @@ -1068,10 +1118,11 @@ static void msft_monitor_device_evt(struct hci_dev *hdev, struct sk_buff *skb) void msft_vendor_evt(struct hci_dev *hdev, void *data, struct sk_buff *skb) { - struct msft_data *msft = hdev->msft_data; + struct msft_data *msft; u8 *evt_prefix; u8 *evt; + msft = msft_data_hold_unless_zero(hdev->msft_data); if (!msft) return; @@ -1081,21 +1132,21 @@ void msft_vendor_evt(struct hci_dev *hdev, void *data, struct sk_buff *skb) if (msft->evt_prefix_len > 0) { evt_prefix = msft_skb_pull(hdev, skb, 0, msft->evt_prefix_len); if (!evt_prefix) - return; + goto done; if (memcmp(evt_prefix, msft->evt_prefix, msft->evt_prefix_len)) - return; + goto done; } /* Every event starts at least with an event code and the rest of * the data is variable and depends on the event code. */ if (skb->len < 1) - return; + goto done; evt = msft_skb_pull(hdev, skb, 0, sizeof(*evt)); if (!evt) - return; + goto done; hci_dev_lock(hdev); @@ -1112,13 +1163,24 @@ void msft_vendor_evt(struct hci_dev *hdev, void *data, struct sk_buff *skb) } hci_dev_unlock(hdev); + +done: + msft_data_put(msft); } __u64 msft_get_features(struct hci_dev *hdev) { - struct msft_data *msft = hdev->msft_data; + struct msft_data *msft; + unsigned long long features; + + msft = msft_data_hold_unless_zero(hdev->msft_data); + if (!msft) + return 0; + + features = msft->features; - return msft ? msft->features : 0; + msft_data_put(msft); + return features; } static void msft_le_set_advertisement_filter_enable_cb(struct hci_dev *hdev, @@ -1152,37 +1214,48 @@ static void msft_le_set_advertisement_filter_enable_cb(struct hci_dev *hdev, /* This function requires the caller holds hci_req_sync_lock */ int msft_add_monitor_pattern(struct hci_dev *hdev, struct adv_monitor *monitor) { - struct msft_data *msft = hdev->msft_data; + struct msft_data *msft; + int err; + msft = msft_data_hold_unless_zero(hdev->msft_data); if (!msft) return -EOPNOTSUPP; - if (msft->resuming || msft->suspending) + if (msft->resuming || msft->suspending) { + msft_data_put(msft); return -EBUSY; + } - return msft_add_monitor_sync(hdev, monitor); + err = msft_add_monitor_sync(hdev, monitor); + msft_data_put(msft); + return err; } /* This function requires the caller holds hci_req_sync_lock */ int msft_remove_monitor(struct hci_dev *hdev, struct adv_monitor *monitor) { - struct msft_data *msft = hdev->msft_data; + struct msft_data *msft; + int err; + msft = msft_data_hold_unless_zero(hdev->msft_data); if (!msft) return -EOPNOTSUPP; if (msft->resuming || msft->suspending) return -EBUSY; - return msft_remove_monitor_sync(hdev, monitor); + err = msft_remove_monitor_sync(hdev, monitor); + msft_data_put(msft); + return err; } int msft_set_filter_enable(struct hci_dev *hdev, bool enable) { struct msft_cp_le_set_advertisement_filter_enable cp; - struct msft_data *msft = hdev->msft_data; + struct msft_data *msft; int err; + msft = msft_data_hold_unless_zero(hdev->msft_data); if (!msft) return -EOPNOTSUPP; @@ -1193,6 +1266,7 @@ int msft_set_filter_enable(struct hci_dev *hdev, bool enable) msft_le_set_advertisement_filter_enable_cb(hdev, &cp, err); + msft_data_put(msft); return 0; }
Hi, could you review this patch? Now *not static* msft functions hold and put hdev->msft_data. It prevents from potential and real use-after-free bugs. How msft is used after freed: [use] msft_do_close() msft = hdev->msft_data; if (!msft) ...(1) <- passed. return; mutex_lock(&msft->filter_lock); ...(4) <- used after freed. [free] msft_unregister() msft = hdev->msft_data; hdev->msft_data = NULL; ...(2) kfree(msft); ...(3) <- msft is freed. ================================================================== BUG: KASAN: slab-use-after-free in __mutex_lock_common kernel/locking/mutex.c:587 [inline] BUG: KASAN: slab-use-after-free in __mutex_lock+0x8f/0xc30 kernel/locking/mutex.c:752 Read of size 8 at addr ffff888106cbbca8 by task kworker/u5:2/309 CPU: 0 PID: 309 Comm: kworker/u5:2 Not tainted 6.9.0-rc5+ #5 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.15.0-1 04/01/2014 Workqueue: hci4 hci_error_reset Call Trace: <TASK> __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0xcd/0x140 lib/dump_stack.c:114 print_address_description mm/kasan/report.c:377 [inline] print_report+0x191/0x560 mm/kasan/report.c:488 kasan_report+0xe2/0x120 mm/kasan/report.c:601 __asan_report_load8_noabort+0x18/0x20 mm/kasan/report_generic.c:381 __mutex_lock_common kernel/locking/mutex.c:587 [inline] __mutex_lock+0x8f/0xc30 kernel/locking/mutex.c:752 mutex_lock_nested+0x1f/0x30 kernel/locking/mutex.c:804 msft_do_close+0x292/0x700 net/bluetooth/msft.c:694 hci_dev_close_sync+0x906/0xf10 net/bluetooth/hci_sync.c:5168 hci_dev_do_close net/bluetooth/hci_core.c:554 [inline] hci_error_reset+0x152/0x410 net/bluetooth/hci_core.c:1091 process_one_work kernel/workqueue.c:3254 [inline] process_scheduled_works+0x90f/0x1530 kernel/workqueue.c:3335 worker_thread+0x926/0xe70 kernel/workqueue.c:3416 kthread+0x2e3/0x380 kernel/kthread.c:388 ret_from_fork+0x5c/0x90 arch/x86/kernel/process.c:147 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244 </TASK> Allocated by task 7328: kasan_save_stack mm/kasan/common.c:47 [inline] kasan_save_track+0x30/0x70 mm/kasan/common.c:68 kasan_save_alloc_info+0x3c/0x50 mm/kasan/generic.c:565 poison_kmalloc_redzone mm/kasan/common.c:370 [inline] __kasan_kmalloc+0xa2/0xc0 mm/kasan/common.c:387 kasan_kmalloc include/linux/kasan.h:211 [inline] kmalloc_trace+0x20c/0x3e0 mm/slub.c:3997 kmalloc include/linux/slab.h:628 [inline] kzalloc include/linux/slab.h:749 [inline] msft_register+0x66/0x1d0 net/bluetooth/msft.c:760 hci_register_dev+0x85e/0x9a0 net/bluetooth/hci_core.c:2737 __vhci_create_device drivers/bluetooth/hci_vhci.c:438 [inline] vhci_create_device+0x390/0x720 drivers/bluetooth/hci_vhci.c:480 vhci_get_user drivers/bluetooth/hci_vhci.c:537 [inline] vhci_write+0x39b/0x460 drivers/bluetooth/hci_vhci.c:617 call_write_iter include/linux/fs.h:2110 [inline] new_sync_write fs/read_write.c:497 [inline] vfs_write+0x8eb/0xb50 fs/read_write.c:590 ksys_write+0x106/0x1f0 fs/read_write.c:643 __do_sys_write fs/read_write.c:655 [inline] __se_sys_write fs/read_write.c:652 [inline] __x64_sys_write+0x84/0xa0 fs/read_write.c:652 x64_sys_call+0x271a/0x2ce0 arch/x86/include/generated/asm/syscalls_64.h:2 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0x9c/0x130 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x76/0x7e Freed by task 7332: kasan_save_stack mm/kasan/common.c:47 [inline] kasan_save_track+0x30/0x70 mm/kasan/common.c:68 kasan_save_free_info+0x44/0x50 mm/kasan/generic.c:579 poison_slab_object+0x11a/0x190 mm/kasan/common.c:240 __kasan_slab_free+0x3b/0x60 mm/kasan/common.c:256 kasan_slab_free include/linux/kasan.h:184 [inline] slab_free_hook mm/slub.c:2106 [inline] slab_free mm/slub.c:4280 [inline] kfree+0x13c/0x330 mm/slub.c:4390 msft_unregister+0x9d/0x120 net/bluetooth/msft.c:785 hci_unregister_dev+0x1d9/0x520 net/bluetooth/hci_core.c:2771 vhci_release+0x8c/0xe0 drivers/bluetooth/hci_vhci.c:674 __fput+0x36f/0x750 fs/file_table.c:422 ____fput+0x1e/0x30 fs/file_table.c:450 task_work_run+0x1da/0x280 kernel/task_work.c:180 exit_task_work include/linux/task_work.h:38 [inline] do_exit+0x856/0x2210 kernel/exit.c:878 do_group_exit+0x201/0x2c0 kernel/exit.c:1027 get_signal+0x12ff/0x1380 kernel/signal.c:2911 arch_do_signal_or_restart+0x3b/0x650 arch/x86/kernel/signal.c:310 exit_to_user_mode_loop kernel/entry/common.c:111 [inline] exit_to_user_mode_prepare include/linux/entry-common.h:328 [inline] __syscall_exit_to_user_mode_work kernel/entry/common.c:207 [inline] syscall_exit_to_user_mode+0xcc/0x2a0 kernel/entry/common.c:218 do_syscall_64+0xa8/0x130 arch/x86/entry/common.c:89 entry_SYSCALL_64_after_hwframe+0x76/0x7e The buggy address belongs to the object at ffff888106cbbc00 which belongs to the cache kmalloc-256 of size 256 The buggy address is located 168 bytes inside of freed 256-byte region [ffff888106cbbc00, ffff888106cbbd00) The buggy address belongs to the physical page: page: refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x106cba head: order:1 entire_mapcount:0 nr_pages_mapped:0 pincount:0 flags: 0x17ffffe0000840(slab|head|node=0|zone=2|lastcpupid=0x3fffff) page_type: 0xffffffff() raw: 0017ffffe0000840 ffff888100042040 ffffea00042de590 ffffea00041b3e10 raw: 0000000000000000 00000000000a000a 00000001ffffffff 0000000000000000 head: 0017ffffe0000840 ffff888100042040 ffffea00042de590 ffffea00041b3e10 head: 0000000000000000 00000000000a000a 00000001ffffffff 0000000000000000 head: 0017ffffe0000001 ffffea00041b2e81 dead000000000122 00000000ffffffff head: 0000000200000000 0000000000000000 00000000ffffffff 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff888106cbbb80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ffff888106cbbc00: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >ffff888106cbbc80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff888106cbbd00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ffff888106cbbd80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ================================================================== Fixes: 9e14606d8f38 ("Bluetooth: disable advertisement filters during suspend") Signed-off-by: Sungwoo Kim <iam@sung-woo.kim> --- v2: Move BT_DBG after null checking in msft_data_hold_unless_zero() net/bluetooth/msft.c | 124 ++++++++++++++++++++++++++++++++++--------- 1 file changed, 99 insertions(+), 25 deletions(-)