[SRU Bionic, OEM-5.14, HWE-5.17 1/1] Bluetooth: L2CAP: Fix attempting to access uninitialized memory

[Cengiz Can]

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

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

CVE: CVE-2022-42895
CC: stable at vger.kernel.org
Reported-by: Tamás Koczka <poprdi at google.com>
Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz at intel.com>
Reviewed-by: Tedd Ho-Jeong An <tedd.an at intel.com>
CVE-2022-42895
(cherry picked from commit b1a2cd50c0357f243b7435a732b4e62ba3157a2e)
Signed-off-by: Cengiz Can <cengiz.can at canonical.com>
---
 net/bluetooth/l2cap_core.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/net/bluetooth/l2cap_core.c b/net/bluetooth/l2cap_core.c
index 0c8fa65a0a8a..578714013972 100644
--- a/net/bluetooth/l2cap_core.c
+++ b/net/bluetooth/l2cap_core.c
@@ -3737,7 +3737,8 @@ static int l2cap_parse_conf_req(struct l2cap_chan *chan, void *data, size_t data
 			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);
-- 
2.37.2