Bluetooth: L2CAP: Fix attempting to access uninitialized memory

On l2cap_parse_conf_req the variable efs is only initialized if
remote_efs has been set.

CVE: CVE-2022-42895
CC: stable@vger.kernel.org
Reported-by: Tamás Koczka <poprdi@google.com>
Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>
Reviewed-by: Tedd Ho-Jeong An <tedd.an@intel.com>

diff --git a/net/bluetooth/l2cap_core.c b/net/bluetooth/l2cap_core.c
index 4d8a1d862f6bb09c229c721c104a48aa2e723b37..9c24947aa41ef0b182a270f7d8cc2c119dca40c6 100644 (file)
--- a/net/bluetooth/l2cap_core.c
+++ b/net/bluetooth/l2cap_core.c
@@ -3764,7 +3764,8 @@ done:
                        l2cap_add_conf_opt(&ptr, L2CAP_CONF_RFC,
                                           sizeof(rfc), (unsigned long) &rfc, endptr - ptr);
 
-                       if (test_bit(FLAG_EFS_ENABLE, &chan->flags)) {
+                       if (remote_efs &&
+                           test_bit(FLAG_EFS_ENABLE, &chan->flags)) {
                                chan->remote_id = efs.id;
                                chan->remote_stype = efs.stype;
                                chan->remote_msdu = le16_to_cpu(efs.msdu);