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From: Luiz Augusto von Dentz <luiz.dentz@gmail.com>
To: linux-bluetooth@vger.kernel.org
Subject: [PATCH v1] Bluetooth: hci_sync: Fix UAF on hci_abort_conn_sync
Date: Fri, 16 Feb 2024 15:50:05 -0500
Message-ID: <20240216205005.111967-1-luiz.dentz@gmail.com>
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From: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>

Fixes the following trace where hci_acl_create_conn_sync attempts to
call hci_abort_conn_sync after timeout:

BUG: KASAN: slab-use-after-free in hci_abort_conn_sync
(net/bluetooth/hci_sync.c:5439)
Read of size 2 at addr ffff88800322c032 by task kworker/u3:2/36

Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.2-1.fc38
04/01/2014
Workqueue: hci0 hci_cmd_sync_work
Call Trace:
<TASK>
dump_stack_lvl (./arch/x86/include/asm/irqflags.h:26
./arch/x86/include/asm/irqflags.h:67 ./arch/x86/include/asm/irqflags.h:127
lib/dump_stack.c:107)
print_report (mm/kasan/report.c:378 mm/kasan/report.c:488)
? preempt_count_sub (kernel/sched/core.c:5889)
? __virt_addr_valid (./arch/x86/include/asm/preempt.h:103 (discriminator 1)
./include/linux/rcupdate.h:865 (discriminator 1)
./include/linux/mmzone.h:2026 (discriminator 1)
arch/x86/mm/physaddr.c:65 (discriminator 1))
? hci_abort_conn_sync (net/bluetooth/hci_sync.c:5439)
kasan_report (mm/kasan/report.c:603)
? hci_abort_conn_sync (net/bluetooth/hci_sync.c:5439)
hci_abort_conn_sync (net/bluetooth/hci_sync.c:5439)
? __pfx_hci_abort_conn_sync (net/bluetooth/hci_sync.c:5433)
hci_acl_create_conn_sync (net/bluetooth/hci_sync.c:6681)

Fixes: 456561ba8e49 ("Bluetooth: hci_conn: Only do ACL connections sequentially")
Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>
---
 net/bluetooth/hci_sync.c | 13 ++++---------
 1 file changed, 4 insertions(+), 9 deletions(-)

diff --git a/net/bluetooth/hci_sync.c b/net/bluetooth/hci_sync.c
index b7d8e99e2a30..4a28aef2f01f 100644
--- a/net/bluetooth/hci_sync.c
+++ b/net/bluetooth/hci_sync.c
@@ -6670,15 +6670,10 @@ static int hci_acl_create_conn_sync(struct hci_dev *hdev, void *data)
 	else
 		cp.role_switch = 0x00;
 
-	err = __hci_cmd_sync_status_sk(hdev, HCI_OP_CREATE_CONN,
-				       sizeof(cp), &cp,
-				       HCI_EV_CONN_COMPLETE,
-				       conn->conn_timeout, NULL);
-
-	if (err == -ETIMEDOUT)
-		hci_abort_conn_sync(hdev, conn, HCI_ERROR_LOCAL_HOST_TERM);
-
-	return err;
+	return __hci_cmd_sync_status_sk(hdev, HCI_OP_CREATE_CONN,
+					sizeof(cp), &cp,
+					HCI_EV_CONN_COMPLETE,
+					conn->conn_timeout, NULL);
 }
 
 int hci_connect_acl_sync(struct hci_dev *hdev, struct hci_conn *conn)
-- 
2.43.0