From: Sungwoo Kim iam@sung-woo.kim

[ Upstream commit bcd70260ef56e0aee8a4fc6cd214a419900b0765 ]

By keep sending L2CAP_CONF_REQ packets, chan->num_conf_rsp increases multiple times and eventually it will wrap around the maximum number (i.e., 255). This patch prevents this by adding a boundary check with L2CAP_MAX_CONF_RSP

Btmon log: Bluetooth monitor ver 5.64 = Note: Linux version 6.1.0-rc2 (x86_64) 0.264594 = Note: Bluetooth subsystem version 2.22 0.264636 @ MGMT Open: btmon (privileged) version 1.22 {0x0001} 0.272191 = New Index: 00:00:00:00:00:00 (Primary,Virtual,hci0) [hci0] 13.877604 @ RAW Open: 9496 (privileged) version 2.22 {0x0002} 13.890741 = Open Index: 00:00:00:00:00:00 [hci0] 13.900426 (...)

ACL Data RX: Handle 200 flags 0x00 dlen 1033 #32 [hci0] 14.273106

invalid packet size (12 != 1033) 08 00 01 00 02 01 04 00 01 10 ff ff ............

ACL Data RX: Handle 200 flags 0x00 dlen 1547 #33 [hci0] 14.273561

invalid packet size (14 != 1547) 0a 00 01 00 04 01 06 00 40 00 00 00 00 00 ........@.....

ACL Data RX: Handle 200 flags 0x00 dlen 2061 #34 [hci0] 14.274390

invalid packet size (16 != 2061) 0c 00 01 00 04 01 08 00 40 00 00 00 00 00 00 04 ........@.......

ACL Data RX: Handle 200 flags 0x00 dlen 2061 #35 [hci0] 14.274932

invalid packet size (16 != 2061) 0c 00 01 00 04 01 08 00 40 00 00 00 07 00 03 00 ........@....... = bluetoothd: Bluetooth daemon 5.43 14.401828

ACL Data RX: Handle 200 flags 0x00 dlen 1033 #36 [hci0] 14.275753

invalid packet size (12 != 1033) 08 00 01 00 04 01 04 00 40 00 00 00 ........@...

Signed-off-by: Sungwoo Kim iam@sung-woo.kim Signed-off-by: Luiz Augusto von Dentz luiz.von.dentz@intel.com Signed-off-by: Sasha Levin sashal@kernel.org --- 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 fd6cd47a6c5a..fd95631205a6 100644 --- a/net/bluetooth/l2cap_core.c +++ b/net/bluetooth/l2cap_core.c @@ -4193,7 +4193,8 @@ static inline int l2cap_config_req(struct l2cap_conn *conn,

chan->ident = cmd->ident; l2cap_send_cmd(conn, cmd->ident, L2CAP_CONF_RSP, len, rsp); - chan->num_conf_rsp++; + if (chan->num_conf_rsp < L2CAP_CONF_MAX_CONF_RSP) + chan->num_conf_rsp++;

/* Reset config buffer. */ chan->conf_len = 0;