[PATCH 03/11] Bluetooth: ISO: lock sk in iso_connect_ind

[Pauli Virtanen]

Accessing iso_pi(sk)->conn requires lock_sock, which is not taken in the
"ev3" part of iso_connect_ind.  It may also be NULL if socket has
transitioned away from the LISTEN/CONNECT states before locking.

Fix by adding lock/release. Recheck hcon is valid after lock acquire
where needed.

Fixes: 168d9bf9c7f0 ("Bluetooth: ISO: Reassemble PA data for bcast sink")
Signed-off-by: Pauli Virtanen <pav@xxxxxx>
---
 net/bluetooth/iso.c | 19 +++++++++++--------
 1 file changed, 11 insertions(+), 8 deletions(-)

diff --git a/net/bluetooth/iso.c b/net/bluetooth/iso.c
index dbb8f43052f0..651661833966 100644
--- a/net/bluetooth/iso.c
+++ b/net/bluetooth/iso.c
@@ -2369,7 +2369,7 @@ int iso_connect_ind(struct hci_dev *hdev, bdaddr_t *bdaddr, __u8 *flags)
 
 			lock_sock(sk);
 
-			hcon = iso_pi(sk)->conn->hcon;
+			hcon = iso_pi(sk)->conn ? iso_pi(sk)->conn->hcon : NULL;
 			iso_pi(sk)->qos.bcast.encryption = ev2->encryption;
 
 			if (ev2->num_bis < iso_pi(sk)->bc_num_bis)
@@ -2409,9 +2409,11 @@ int iso_connect_ind(struct hci_dev *hdev, bdaddr_t *bdaddr, __u8 *flags)
 		if (!sk)
 			goto done;
 
-		hcon = iso_pi(sk)->conn->hcon;
+		lock_sock(sk);
+
+		hcon = iso_pi(sk)->conn ? iso_pi(sk)->conn->hcon : NULL;
 		if (!hcon)
-			goto done;
+			goto release3;
 
 		if (ev3->data_status == LE_PA_DATA_TRUNCATED) {
 			/* The controller was unable to retrieve PA data. */
@@ -2419,12 +2421,12 @@ int iso_connect_ind(struct hci_dev *hdev, bdaddr_t *bdaddr, __u8 *flags)
 			       HCI_MAX_PER_AD_TOT_LEN);
 			hcon->le_per_adv_data_len = 0;
 			hcon->le_per_adv_data_offset = 0;
-			goto done;
+			goto release3;
 		}
 
 		if (hcon->le_per_adv_data_offset + ev3->length >
 		    HCI_MAX_PER_AD_TOT_LEN)
-			goto done;
+			goto release3;
 
 		memcpy(hcon->le_per_adv_data + hcon->le_per_adv_data_offset,
 		       ev3->data, ev3->length);
@@ -2443,18 +2445,19 @@ int iso_connect_ind(struct hci_dev *hdev, bdaddr_t *bdaddr, __u8 *flags)
 						    &base_len);
 
 			if (!base || base_len > BASE_MAX_LENGTH)
-				goto done;
+				goto release3;
 
-			lock_sock(sk);
 			memcpy(iso_pi(sk)->base, base, base_len);
 			iso_pi(sk)->base_len = base_len;
-			release_sock(sk);
 		} else {
 			/* This is a PA data fragment. Keep pa_data_len set to 0
 			 * until all data has been reassembled.
 			 */
 			hcon->le_per_adv_data_len = 0;
 		}
+
+release3:
+		release_sock(sk);
 	} else {
 		sk = iso_get_sock(hdev, &hdev->bdaddr, BDADDR_ANY,
 				  BT_LISTEN, iso_match_dst, BDADDR_ANY);
-- 
2.55.0