off-by: Sasha Levin <sashal@kernel.org>
---
 include/net/bluetooth/l2cap.h |  2 ++
 net/bluetooth/l2cap_core.c    | 63 +++++++++++++++++++++++++----------
 2 files changed, 47 insertions(+), 18 deletions(-)

diff --git a/include/net/bluetooth/l2cap.h b/include/net/bluetooth/l2cap.h
index 00e182a22720a..9820ccc379f1c 100644
--- a/include/net/bluetooth/l2cap.h
+++ b/include/net/bluetooth/l2cap.h
@@ -493,6 +493,8 @@ struct l2cap_ecred_reconf_req {
 #define L2CAP_RECONF_SUCCESS		0x0000
 #define L2CAP_RECONF_INVALID_MTU	0x0001
 #define L2CAP_RECONF_INVALID_MPS	0x0002
+#define L2CAP_RECONF_INVALID_CID	0x0003
+#define L2CAP_RECONF_INVALID_PARAMS	0x0004
 
 struct l2cap_ecred_reconf_rsp {
 	__le16 result;
diff --git a/net/bluetooth/l2cap_core.c b/net/bluetooth/l2cap_core.c
index 07b493331fd78..e705b4a171dec 100644
--- a/net/bluetooth/l2cap_core.c
+++ b/net/bluetooth/l2cap_core.c
@@ -5294,14 +5294,14 @@ static inline int l2cap_ecred_reconf_req(struct l2cap_conn *conn,
 	struct l2cap_ecred_reconf_req *req = (void *) data;
 	struct l2cap_ecred_reconf_rsp rsp;
 	u16 mtu, mps, result;
-	struct l2cap_chan *chan;
+	struct l2cap_chan *chan[L2CAP_ECRED_MAX_CID] = {};
 	int i, num_scid;
 
 	if (!enable_ecred)
 		return -EINVAL;
 
-	if (cmd_len < sizeof(*req) || cmd_len - sizeof(*req) % sizeof(u16)) {
-		result = L2CAP_CR_LE_INVALID_PARAMS;
+	if (cmd_len < sizeof(*req) || (cmd_len - sizeof(*req)) % sizeof(u16)) {
+		result = L2CAP_RECONF_INVALID_CID;
 		goto respond;
 	}
 
@@ -5311,42 +5311,69 @@ static inline int l2cap_ecred_reconf_req(struct l2cap_conn *conn,
 	BT_DBG("mtu %u mps %u", mtu, mps);
 
 	if (mtu < L2CAP_ECRED_MIN_MTU) {
-		result = L2CAP_RECONF_INVALID_MTU;
+		result = L2CAP_RECONF_INVALID_PARAMS;
 		goto respond;
 	}
 
 	if (mps < L2CAP_ECRED_MIN_MPS) {
-		result = L2CAP_RECONF_INVALID_MPS;
+		result = L2CAP_RECONF_INVALID_PARAMS;
 		goto respond;
 	}
 
 	cmd_len -= sizeof(*req);
 	num_scid = cmd_len / sizeof(u16);
+
+	if (num_scid > L2CAP_ECRED_MAX_CID) {
+		result = L2CAP_RECONF_INVALID_PARAMS;
+		goto respond;
+	}
+
 	result = L2CAP_RECONF_SUCCESS;
 
+	/* Check if each SCID, MTU and MPS are valid */
 	for (i = 0; i < num_scid; i++) {
 		u16 scid;
 
 		scid = __le16_to_cpu(req->scid[i]);
-		if (!scid)
-			return -EPROTO;
+		if (!scid) {
+			result = L2CAP_RECONF_INVALID_CID;
+			goto respond;
+		}
 
-		chan = __l2cap_get_chan_by_dcid(conn, scid);
-		if (!chan)
-			continue;
+		chan[i] = __l2cap_get_chan_by_dcid(conn, scid);
+		if (!chan[i]) {
+			result = L2CAP_RECONF_INVALID_CID;
+			goto respond;
+		}
 
-		/* If the MTU value is decreased for any of the included
-		 * channels, then the receiver shall disconnect all
-		 * included channels.
+		/* The MTU field shall be greater than or equal to the greatest
+		 * current MTU size of these channels.
 		 */
-		if (chan->omtu > mtu) {
-			BT_ERR("chan %p decreased MTU %u -> %u", chan,
-			       chan->omtu, mtu);
+		if (chan[i]->omtu > mtu) {
+			BT_ERR("chan %p decreased MTU %u -> %u", chan[i],
+			       chan[i]->omtu, mtu);
 			result = L2CAP_RECONF_INVALID_MTU;
+			goto respond;
 		}
 
-		chan->omtu = mtu;
-		chan->remote_mps = mps;
+		/* If more than one channel is being configured, the MPS field
+		 * shall be greater than or equal to the current MPS size of
+		 * each of these channels. If only one channel is being
+		 * configured, the MPS field may be less than the current MPS
+		 * of that channel.
+		 */
+		if (chan[i]->remote_mps >= mps && i) {
+			BT_ERR("chan %p decreased MPS %u -> %u", chan[i],
+			       chan[i]->remote_mps, mps);
+			result = L2CAP_RECONF_INVALID_MPS;
+			goto respond;
+		}
+	}
+
+	/* Commit the new MTU and MPS values after checking they are valid */
+	for (i = 0; i < num_scid; i++) {
+		chan[i]->omtu = mtu;
+		chan[i]->remote_mps = mps;
 	}
 
 respond:
-- 
2.51.0[PATCH 6.19 470/844] Bluetooth: L2CAP: Fix invalid response to L2CAP_ECRED_RECONF_REQSasha Levin <sashal@kernel.org> undefinedlinux-kernel@vger.kernel.org, stable@vger.kernel.org undefined undefined undefined!†¨#