[PATCH 6.1.y 0/2] Bluetooth: backport CVE-2023-53762 to 6.1.y

[PATCH 6.1.y 0/2] Bluetooth: backport CVE-2023-53762 to 6.1.y

[Artem Dinaburg]

Hi Greg, Sasha, and Bluetooth maintainers,

I am backporting CVEss still missing from 6.1.y.
This pair handles CVE-2023-53762 in disconnect-all cleanup. The
second patch is the immediate upstream liveness follow-up to the UAF fix,
so I kept the two together.

Both changes are already inherited by v6.6 and every later mainline
release.

Could you please queue the pair for 6.1.y?

Thanks,
Artem Dinaburg

AI assistance: An LLM helped find the missing CVE fix, adapt
it, and prepare the draft; I reviewed the code and build output.

Luiz Augusto von Dentz (1):
  Bluetooth: hci_sync: Fix UAF in hci_disconnect_all_sync

Pauli Virtanen (1):
  Bluetooth: hci_sync: always check if connection is alive before
    deleting

 net/bluetooth/hci_sync.c | 58 +++++++++++++++++++++++++---------------
 1 file changed, 37 insertions(+), 21 deletions(-)

-- 
2.39.5

[PATCH 6.1.y 1/2] Bluetooth: hci_sync: Fix UAF in hci_disconnect_all_sync

[Artem Dinaburg]

From: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>

[ Upstream commit 94d9ba9f9888b748d4abd2aa1547af56ae85f772 ]

Use-after-free can occur in hci_disconnect_all_sync if a connection is
deleted by concurrent processing of a controller event.

To prevent this the code now tries to iterate over the list backwards
to ensure the links are cleanup before its parents, also it no longer
relies on a cursor, instead it always uses the last element since
hci_abort_conn_sync is guaranteed to call hci_conn_del.

UAF crash log:
==================================================================
BUG: KASAN: slab-use-after-free in hci_set_powered_sync
(net/bluetooth/hci_sync.c:5424) [bluetooth]
Read of size 8 at addr ffff888009d9c000 by task kworker/u9:0/124

CPU: 0 PID: 124 Comm: kworker/u9:0 Tainted: G        W
6.5.0-rc1+ #10
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS
1.16.2-1.fc38 04/01/2014
Workqueue: hci0 hci_cmd_sync_work [bluetooth]
Call Trace:
 <TASK>
 dump_stack_lvl+0x5b/0x90
 print_report+0xcf/0x670
 ? __virt_addr_valid+0xdd/0x160
 ? hci_set_powered_sync+0x2c9/0x4a0 [bluetooth]
 kasan_report+0xa6/0xe0
 ? hci_set_powered_sync+0x2c9/0x4a0 [bluetooth]
 ? __pfx_set_powered_sync+0x10/0x10 [bluetooth]
 hci_set_powered_sync+0x2c9/0x4a0 [bluetooth]
 ? __pfx_hci_set_powered_sync+0x10/0x10 [bluetooth]
 ? __pfx_lock_release+0x10/0x10
 ? __pfx_set_powered_sync+0x10/0x10 [bluetooth]
 hci_cmd_sync_work+0x137/0x220 [bluetooth]
 process_one_work+0x526/0x9d0
 ? __pfx_process_one_work+0x10/0x10
 ? __pfx_do_raw_spin_lock+0x10/0x10
 ? mark_held_locks+0x1a/0x90
 worker_thread+0x92/0x630
 ? __pfx_worker_thread+0x10/0x10
 kthread+0x196/0x1e0
 ? __pfx_kthread+0x10/0x10
 ret_from_fork+0x2c/0x50
 </TASK>

Allocated by task 1782:
 kasan_save_stack+0x33/0x60
 kasan_set_track+0x25/0x30
 __kasan_kmalloc+0x8f/0xa0
 hci_conn_add+0xa5/0xa80 [bluetooth]
 hci_bind_cis+0x881/0x9b0 [bluetooth]
 iso_connect_cis+0x121/0x520 [bluetooth]
 iso_sock_connect+0x3f6/0x790 [bluetooth]
 __sys_connect+0x109/0x130
 __x64_sys_connect+0x40/0x50
 do_syscall_64+0x60/0x90
 entry_SYSCALL_64_after_hwframe+0x6e/0xd8

Freed by task 695:
 kasan_save_stack+0x33/0x60
 kasan_set_track+0x25/0x30
 kasan_save_free_info+0x2b/0x50
 __kasan_slab_free+0x10a/0x180
 __kmem_cache_free+0x14d/0x2e0
 device_release+0x5d/0xf0
 kobject_put+0xdf/0x270
 hci_disconn_complete_evt+0x274/0x3a0 [bluetooth]
 hci_event_packet+0x579/0x7e0 [bluetooth]
 hci_rx_work+0x287/0xaa0 [bluetooth]
 process_one_work+0x526/0x9d0
 worker_thread+0x92/0x630
 kthread+0x196/0x1e0
 ret_from_fork+0x2c/0x50
==================================================================

Fixes: 182ee45da083 ("Bluetooth: hci_sync: Rework hci_suspend_notifier")
Signed-off-by: Pauli Virtanen <pav@iki.fi>
Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>

[ Backport to 6.1.y: the source change is unchanged; only hunk locations
  in hci_sync.c differ. ]
Assisted-by: LLM
Signed-off-by: Artem Dinaburg <artem@trailofbits.com>
---
Stable submission note: patch 1/2 in the CVE-2023-53762 series for Linux
6.1.y.

CVE: CVE-2023-53762

Build: This patch was included in an x86_64 allmodconfig and
CONFIG_WERROR=y build.
It produced vmlinux and modules with no new warnings or errors.


 net/bluetooth/hci_sync.c | 55 +++++++++++++++++++++++++---------------
 1 file changed, 35 insertions(+), 20 deletions(-)

diff --git a/net/bluetooth/hci_sync.c b/net/bluetooth/hci_sync.c
index d5856448d46782..da9e6e55bc1d00 100644
--- a/net/bluetooth/hci_sync.c
+++ b/net/bluetooth/hci_sync.c
@@ -5587,6 +5587,7 @@ int hci_abort_conn_sync(struct hci_dev *hdev, struct hci_conn *conn, u8 reason)
 {
 	int err = 0;
 	u16 handle = conn->handle;
+	struct hci_conn *c;
 
 	switch (conn->state) {
 	case BT_CONNECTED:
@@ -5600,43 +5601,57 @@ int hci_abort_conn_sync(struct hci_dev *hdev, struct hci_conn *conn, u8 reason)
 		err = hci_reject_conn_sync(hdev, conn, reason);
 		break;
 	default:
+		hci_dev_lock(hdev);
 		conn->state = BT_CLOSED;
+		hci_disconn_cfm(conn, reason);
+		hci_conn_del(conn);
+		hci_dev_unlock(hdev);
 		return 0;
 	}
 
+	hci_dev_lock(hdev);
+
+	/* Check if the connection hasn't been cleanup while waiting
+	 * commands to complete.
+	 */
+	c = hci_conn_hash_lookup_handle(hdev, handle);
+	if (!c || c != conn) {
+		err = 0;
+		goto unlock;
+	}
+
 	/* Cleanup hci_conn object if it cannot be cancelled as it
 	 * likelly means the controller and host stack are out of sync
 	 * or in case of LE it was still scanning so it can be cleanup
 	 * safely.
 	 */
-	if (err) {
-		struct hci_conn *c;
-
-		/* Check if the connection hasn't been cleanup while waiting
-		 * commands to complete.
-		 */
-		c = hci_conn_hash_lookup_handle(hdev, handle);
-		if (!c || c != conn)
-			return 0;
-
-		hci_dev_lock(hdev);
-		hci_conn_failed(conn, err);
-		hci_dev_unlock(hdev);
-	}
+	hci_conn_failed(conn, reason);
 
+unlock:
+	hci_dev_unlock(hdev);
 	return err;
 }
 
 static int hci_disconnect_all_sync(struct hci_dev *hdev, u8 reason)
 {
-	struct hci_conn *conn, *tmp;
-	int err;
+	struct list_head *head = &hdev->conn_hash.list;
+	struct hci_conn *conn;
 
-	list_for_each_entry_safe(conn, tmp, &hdev->conn_hash.list, list) {
-		err = hci_abort_conn_sync(hdev, conn, reason);
-		if (err)
-			return err;
+	rcu_read_lock();
+	while ((conn = list_first_or_null_rcu(head, struct hci_conn, list))) {
+		/* Make sure the connection is not freed while unlocking */
+		conn = hci_conn_get(conn);
+		rcu_read_unlock();
+		/* Disregard possible errors since hci_conn_del shall have been
+		 * called even in case of errors had occurred since it would
+		 * then cause hci_conn_failed to be called which calls
+		 * hci_conn_del internally.
+		 */
+		hci_abort_conn_sync(hdev, conn, reason);
+		hci_conn_put(conn);
+		rcu_read_lock();
 	}
+	rcu_read_unlock();
 
 	return 0;
 }
-- 
2.39.5

RE: Bluetooth: backport CVE-2023-53762 to 6.1.y

[bluez.test.bot]

[-- Attachment #1: Type: text/plain, Size: 847 bytes --]

This is an automated email and please do not reply to this email.

Dear Submitter,

Thank you for submitting the patches to the linux bluetooth mailing list.
While preparing the CI tests, the patches you submitted couldn't be applied to the current HEAD of the repository.

----- Output -----

error: patch failed: net/bluetooth/hci_sync.c:5587
error: net/bluetooth/hci_sync.c: patch does not apply
hint: Use 'git am --show-current-patch=diff' to see the failed patch
hint: When you have resolved this problem, run "git am --continue".
hint: If you prefer to skip this patch, run "git am --skip" instead.
hint: To restore the original branch and stop patching, run "git am --abort".
hint: Disable this message with "git config set advice.mergeConflict false"

Please resolve the issue and submit the patches again.


---
Regards,
Linux Bluetooth

[PATCH 6.1.y 2/2] Bluetooth: hci_sync: always check if connection is alive before deleting

[Artem Dinaburg]

From: Pauli Virtanen <pav@iki.fi>

[ Upstream commit a239110ee8e0b0aafa265f0d54f7a16744855e70 ]

In hci_abort_conn_sync it is possible that conn is deleted concurrently
by something else, also e.g. when waiting for hdev->lock.  This causes
double deletion of the conn, so UAF or conn_hash.list corruption.

Fix by having all code paths check that the connection is still in
conn_hash before deleting it, while holding hdev->lock which prevents
any races.

Log (when powering off while BAP streaming, occurs rarely):
=======================================================================
kernel BUG at lib/list_debug.c:56!
...
 ? __list_del_entry_valid (lib/list_debug.c:56)
 hci_conn_del (net/bluetooth/hci_conn.c:154) bluetooth
 hci_abort_conn_sync (net/bluetooth/hci_sync.c:5415) bluetooth
 ? __pfx_hci_abort_conn_sync+0x10/0x10 [bluetooth]
 ? lock_release+0x1d5/0x3c0
 ? hci_disconnect_all_sync.constprop.0+0xb2/0x230 [bluetooth]
 ? __pfx_lock_release+0x10/0x10
 ? __kmem_cache_free+0x14d/0x2e0
 hci_disconnect_all_sync.constprop.0+0xda/0x230 [bluetooth]
 ? __pfx_hci_disconnect_all_sync.constprop.0+0x10/0x10 [bluetooth]
 ? hci_clear_adv_sync+0x14f/0x170 [bluetooth]
 ? __pfx_set_powered_sync+0x10/0x10 [bluetooth]
 hci_set_powered_sync+0x293/0x450 [bluetooth]
=======================================================================

Fixes: 94d9ba9f9888 ("Bluetooth: hci_sync: Fix UAF in hci_disconnect_all_sync")
Signed-off-by: Pauli Virtanen <pav@iki.fi>
Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>

[ Backport to 6.1.y follow-up to 94d9ba9f9888: this tree lacks the later
  BT_OPEN and BT_BOUND special cases, so retain its existing state
  switch and add the common liveness check. ]
Assisted-by: LLM
Signed-off-by: Artem Dinaburg <artem@trailofbits.com>
---
Stable submission note: patch 2/2 in the CVE-2023-53762 series for Linux
6.1.y.

CVE: CVE-2023-53762

Build: This patch was included in an x86_64 allmodconfig and
CONFIG_WERROR=y build.
It produced vmlinux and modules with no new warnings or errors.

 net/bluetooth/hci_sync.c | 21 +++++++++++----------
 1 file changed, 11 insertions(+), 10 deletions(-)

diff --git a/net/bluetooth/hci_sync.c b/net/bluetooth/hci_sync.c
index da9e6e55bc1d00..08e90dab73459b 100644
--- a/net/bluetooth/hci_sync.c
+++ b/net/bluetooth/hci_sync.c
@@ -5587,6 +5587,7 @@ int hci_abort_conn_sync(struct hci_dev *hdev, struct hci_conn *conn, u8 reason)
 {
 	int err = 0;
 	u16 handle = conn->handle;
+	bool disconnect = false;
 	struct hci_conn *c;
 
 	switch (conn->state) {
@@ -5601,19 +5602,13 @@ int hci_abort_conn_sync(struct hci_dev *hdev, struct hci_conn *conn, u8 reason)
 		err = hci_reject_conn_sync(hdev, conn, reason);
 		break;
 	default:
-		hci_dev_lock(hdev);
-		conn->state = BT_CLOSED;
-		hci_disconn_cfm(conn, reason);
-		hci_conn_del(conn);
-		hci_dev_unlock(hdev);
-		return 0;
+		disconnect = true;
+		break;
 	}
 
 	hci_dev_lock(hdev);
 
-	/* Check if the connection hasn't been cleanup while waiting
-	 * commands to complete.
-	 */
+	/* Check if the connection has been cleaned up concurrently */
 	c = hci_conn_hash_lookup_handle(hdev, handle);
 	if (!c || c != conn) {
 		err = 0;
@@ -5625,7 +5620,13 @@ int hci_abort_conn_sync(struct hci_dev *hdev, struct hci_conn *conn, u8 reason)
 	 * or in case of LE it was still scanning so it can be cleanup
 	 * safely.
 	 */
-	hci_conn_failed(conn, reason);
+	if (disconnect) {
+		conn->state = BT_CLOSED;
+		hci_disconn_cfm(conn, reason);
+		hci_conn_del(conn);
+	} else {
+		hci_conn_failed(conn, reason);
+	}
 
 unlock:
 	hci_dev_unlock(hdev);
-- 
2.39.5

Re: [PATCH 6.1.y 0/2] Bluetooth: backport CVE-2023-53762 to 6.1.y

[Sasha Levin]

> This pair handles CVE-2023-53762 in disconnect-all cleanup. The
> second patch is the immediate upstream liveness follow-up to the UAF fix,
> so I kept the two together.
>
> Both changes are already inherited by v6.6 and every later mainline
> release.
>
> Could you please queue the pair for 6.1.y?

Queued the pair for 6.1, thanks.

-- 
Thanks,
Sasha