From d50512e6312824861ce342eb68bb1eb7dea984e2 Mon Sep 17 00:00:00 2001 From: Artem Savkov Date: Mon, 21 Jun 2021 12:09:28 +0200 Subject: [PATCH] bluetooth: eliminate the potential race condition when removing the HCI controller Kernels: 4.18.0-305.el8 4.18.0-305.3.1.el8_4 4.18.0-305.7.1.el8_4 Changes since last build: [x86_64]: hci_request.o: changed function: hci_req_sync [ppc64le]: hci_request.o: changed function: bg_scan_update hci_request.o: changed function: connectable_update_work hci_request.o: changed function: discov_off hci_request.o: changed function: discov_update hci_request.o: changed function: discoverable_update_work hci_request.o: changed function: hci_req_sync hci_request.o: changed function: le_scan_disable_work hci_request.o: changed function: le_scan_restart_work hci_request.o: changed function: scan_update_work --------------------------- Kernels: 4.18.0-305.el8 4.18.0-305.3.1.el8_4 4.18.0-305.7.1.el8_4 Modifications: none Z-MR: https://gitlab.com/redhat/rhel/src/kernel/rhel-8/-/merge_requests/804 commit 84466ca3bdf0d5d77d4c8a851336406627de2628 Author: Gopal Tiwari Date: Mon Jun 14 13:47:30 2021 +0530 bluetooth: eliminate the potential race condition when removing the HCI controller Bugzilla: https://bugzilla.redhat.com/1971464 CVE: CVE-2021-32399 Y-Commit: 54c81477df19422cbc3c8cf3b555159ff642f15b O-Bugzilla: https://bugzilla.redhat.com/show_bug.cgi?id=1971488 Upstream: Merged Testing: Sanity_only. commit e2cb6b891ad2b8caa9131e3be70f45243df82a80 Author: Lin Ma Date: Mon Apr 12 19:17:57 2021 +0800 bluetooth: eliminate the potential race condition when removing the HCI controller There is a possible race condition vulnerability between issuing a HCI command and removing the cont. Specifically, functions hci_req_sync() and hci_dev_do_close() can race each other like below: thread-A in hci_req_sync() | thread-B in hci_dev_do_close() | hci_req_sync_lock(hdev); test_bit(HCI_UP, &hdev->flags); | ... | test_and_clear_bit(HCI_UP, &hdev->flags) hci_req_sync_lock(hdev); | | In this commit we alter the sequence in function hci_req_sync(). Hence, the thread-A cannot issue th. Signed-off-by: Lin Ma Cc: Marcel Holtmann Fixes: 7c6a329e4447 ("[Bluetooth] Fix regression from using default link policy") Signed-off-by: Greg Kroah-Hartman (cherry picked from commit e2cb6b891ad2b8caa9131e3be70f45243df82a80) Signed-off-by: Gopal Tiwari Signed-off-by: Jan Stancek Signed-off-by: Artem Savkov Acked-by: Yannick Cote Acked-by: Joe Lawrence --- net/bluetooth/hci_request.c | 12 ++++++++---- 1 file changed, 8 insertions(+), 4 deletions(-) diff --git a/net/bluetooth/hci_request.c b/net/bluetooth/hci_request.c index cf1b42ec40af97..ca9088d439460e 100644 --- a/net/bluetooth/hci_request.c +++ b/net/bluetooth/hci_request.c @@ -274,12 +274,16 @@ int hci_req_sync(struct hci_dev *hdev, int (*req)(struct hci_request *req, { int ret; - if (!test_bit(HCI_UP, &hdev->flags)) - return -ENETDOWN; - /* Serialize all requests */ hci_req_sync_lock(hdev); - ret = __hci_req_sync(hdev, req, opt, timeout, hci_status); + /* check the state after obtaing the lock to protect the HCI_UP + * against any races from hci_dev_do_close when the controller + * gets removed. + */ + if (test_bit(HCI_UP, &hdev->flags)) + ret = __hci_req_sync(hdev, req, opt, timeout, hci_status); + else + ret = -ENETDOWN; hci_req_sync_unlock(hdev); return ret; -- 2.26.3