diff options
| author | Ruihan Li <lrh2000@pku.edu.cn> | 2023-05-03 21:39:34 +0800 |
|---|---|---|
| committer | Luiz Augusto von Dentz <luiz.von.dentz@intel.com> | 2023-05-19 15:37:45 -0700 |
| commit | ca1fd42e7dbfcb34890ffbf1f2f4b356776dab6f (patch) | |
| tree | d9d20f006026eff3205997d33ffe564d3db4c893 /net/bluetooth/hci_conn.c | |
| parent | 9025944fddfed5966c8f102f1fe921ab3aee2c12 (diff) | |
Bluetooth: Fix potential double free caused by hci_conn_unlink
The hci_conn_unlink function is being called by hci_conn_del, which
means it should not call hci_conn_del with the input parameter conn
again. If it does, conn may have already been released when
hci_conn_unlink returns, leading to potential UAF and double-free
issues.
This patch resolves the problem by modifying hci_conn_unlink to release
only conn's child links when necessary, but never release conn itself.
Reported-by: syzbot+690b90b14f14f43f4688@syzkaller.appspotmail.com
Closes: https://lore.kernel.org/linux-bluetooth/000000000000484a8205faafe216@google.com/
Fixes: 06149746e720 ("Bluetooth: hci_conn: Add support for linking multiple hcon")
Signed-off-by: Ruihan Li <lrh2000@pku.edu.cn>
Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>
Reported-by: syzbot+690b90b14f14f43f4688@syzkaller.appspotmail.com
Reported-by: Luiz Augusto von Dentz <luiz.dentz@gmail.com>
Reported-by: syzbot+8bb72f86fc823817bc5d@syzkaller.appspotmail.com
Diffstat (limited to 'net/bluetooth/hci_conn.c')
| -rw-r--r-- | net/bluetooth/hci_conn.c | 21 |
1 files changed, 12 insertions, 9 deletions
diff --git a/net/bluetooth/hci_conn.c b/net/bluetooth/hci_conn.c index 640b951bf40a..70e1655a9df6 100644 --- a/net/bluetooth/hci_conn.c +++ b/net/bluetooth/hci_conn.c @@ -1083,8 +1083,18 @@ static void hci_conn_unlink(struct hci_conn *conn) if (!conn->parent) { struct hci_link *link, *t; - list_for_each_entry_safe(link, t, &conn->link_list, list) - hci_conn_unlink(link->conn); + list_for_each_entry_safe(link, t, &conn->link_list, list) { + struct hci_conn *child = link->conn; + + hci_conn_unlink(child); + + /* 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 (child->handle == HCI_CONN_HANDLE_UNSET) + hci_conn_del(child); + } return; } @@ -1100,13 +1110,6 @@ static void hci_conn_unlink(struct hci_conn *conn) kfree(conn->link); conn->link = NULL; - - /* 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 (conn->handle == HCI_CONN_HANDLE_UNSET) - hci_conn_del(conn); } int hci_conn_del(struct hci_conn *conn) |