From: Luiz Augusto von Dentz luiz.von.dentz@intel.com
commit 5dc7d23e167e2882ef118456ceccd57873e876d8 upstream.
This fixes the following trace:
================================================================== BUG: KASAN: slab-use-after-free in hci_conn_del+0xba/0x3a0 Write of size 8 at addr ffff88800208e9c8 by task iso-tester/31
CPU: 0 PID: 31 Comm: iso-tester Not tainted 6.3.0-rc2-g991aa4a69a47 #4716 Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.1-2.fc36 04/01/2014 Call Trace: <TASK> dump_stack_lvl+0x1d/0x70 print_report+0xce/0x610 ? __virt_addr_valid+0xd4/0x150 ? hci_conn_del+0xba/0x3a0 kasan_report+0xdd/0x110 ? hci_conn_del+0xba/0x3a0 hci_conn_del+0xba/0x3a0 hci_conn_hash_flush+0xf2/0x120 hci_dev_close_sync+0x388/0x920 hci_unregister_dev+0x122/0x260 vhci_release+0x4f/0x90 __fput+0x102/0x430 task_work_run+0xf1/0x160 ? __pfx_task_work_run+0x10/0x10 ? mark_held_locks+0x24/0x90 exit_to_user_mode_prepare+0x170/0x180 syscall_exit_to_user_mode+0x19/0x50 do_syscall_64+0x4e/0x90 entry_SYSCALL_64_after_hwframe+0x70/0xda
Fixes: 0f00cd322d22 ("Bluetooth: Free potentially unfreed SCO connection") Link: https://syzkaller.appspot.com/bug?extid=8bb72f86fc823817bc5d Cc: stable@vger.kernel.org Signed-off-by: Luiz Augusto von Dentz luiz.von.dentz@intel.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- net/bluetooth/hci_conn.c | 30 ++++++++++++++++++++++++------ 1 file changed, 24 insertions(+), 6 deletions(-)
--- a/net/bluetooth/hci_conn.c +++ b/net/bluetooth/hci_conn.c @@ -1051,6 +1051,17 @@ struct hci_conn *hci_conn_add(struct hci return conn; }
+static bool hci_conn_unlink(struct hci_conn *conn) +{ + if (!conn->link) + return false; + + conn->link->link = NULL; + conn->link = NULL; + + return true; +} + int hci_conn_del(struct hci_conn *conn) { struct hci_dev *hdev = conn->hdev; @@ -1062,15 +1073,16 @@ int hci_conn_del(struct hci_conn *conn) cancel_delayed_work_sync(&conn->idle_work);
if (conn->type == ACL_LINK) { - struct hci_conn *sco = conn->link; - if (sco) { - sco->link = NULL; + struct hci_conn *link = conn->link; + + if (link) { + hci_conn_unlink(conn); /* Due to race, SCO connection might be not established * yet at this point. Delete it now, otherwise it is * possible for it to be stuck and can't be deleted. */ - if (sco->handle == HCI_CONN_HANDLE_UNSET) - hci_conn_del(sco); + if (link->handle == HCI_CONN_HANDLE_UNSET) + hci_conn_del(link); }
/* Unacked frames */ @@ -1086,7 +1098,7 @@ int hci_conn_del(struct hci_conn *conn) struct hci_conn *acl = conn->link;
if (acl) { - acl->link = NULL; + hci_conn_unlink(conn); hci_conn_drop(acl); }
@@ -2445,6 +2457,12 @@ void hci_conn_hash_flush(struct hci_dev c->state = BT_CLOSED;
hci_disconn_cfm(c, HCI_ERROR_LOCAL_HOST_TERM); + + /* Unlink before deleting otherwise it is possible that + * hci_conn_del removes the link which may cause the list to + * contain items already freed. + */ + hci_conn_unlink(c); hci_conn_del(c); } }