Bluetooth: Improve setsockopt() handling of malformed user input

The bt_copy_from_sockptr() return value is being misinterpreted by most
users: a non-zero result is mistakenly assumed to represent an error code,
but actually indicates the number of bytes that could not be copied.

Remove bt_copy_from_sockptr() and adapt callers to use
copy_safe_from_sockptr().

For sco_sock_setsockopt() (case BT_CODEC) use copy_struct_from_sockptr() to
scrub parts of uninitialized buffer.

Opportunistically, rename `len` to `optlen` in hci_sock_setsockopt_old()
and hci_sock_setsockopt().

Fixes: 51eda36d33e4 ("Bluetooth: SCO: Fix not validating setsockopt user input")
Fixes: a97de7bff13b ("Bluetooth: RFCOMM: Fix not validating setsockopt user input")
Fixes: 4f3951242ace ("Bluetooth: L2CAP: Fix not validating setsockopt user input")
Fixes: 9e8742cdfc4b ("Bluetooth: ISO: Fix not validating setsockopt user input")
Fixes: b2186061d604 ("Bluetooth: hci_sock: Fix not validating setsockopt user input")
Reviewed-by: Luiz Augusto von Dentz <[email protected]>
Reviewed-by: David Wei <[email protected]>
Signed-off-by: Michal Luczaj <[email protected]>
Signed-off-by: Luiz Augusto von Dentz <[email protected]>

1 files changed, 11 insertions, 9 deletions

diff --git a/net/bluetooth/l2cap_sock.c b/net/bluetooth/l2cap_sock.c
index 18e89e764f3b..3d2553dcdb1b 100644
--- a/net/bluetooth/l2cap_sock.c
+++ b/net/bluetooth/l2cap_sock.c
@@ -755,7 +755,8 @@ static int l2cap_sock_setsockopt_old(struct socket *sock, int optname,
 		opts.max_tx   = chan->max_tx;
 		opts.txwin_size = chan->tx_win;
 
-		err = bt_copy_from_sockptr(&opts, sizeof(opts), optval, optlen);
+		err = copy_safe_from_sockptr(&opts, sizeof(opts), optval,
+					     optlen);
 		if (err)
 			break;
 
@@ -800,7 +801,7 @@ static int l2cap_sock_setsockopt_old(struct socket *sock, int optname,
 		break;
 
 	case L2CAP_LM:
-		err = bt_copy_from_sockptr(&opt, sizeof(opt), optval, optlen);
+		err = copy_safe_from_sockptr(&opt, sizeof(opt), optval, optlen);
 		if (err)
 			break;
 
@@ -909,7 +910,7 @@ static int l2cap_sock_setsockopt(struct socket *sock, int level, int optname,
 
 		sec.level = BT_SECURITY_LOW;
 
-		err = bt_copy_from_sockptr(&sec, sizeof(sec), optval, optlen);
+		err = copy_safe_from_sockptr(&sec, sizeof(sec), optval, optlen);
 		if (err)
 			break;
 
@@ -956,7 +957,7 @@ static int l2cap_sock_setsockopt(struct socket *sock, int level, int optname,
 			break;
 		}
 
-		err = bt_copy_from_sockptr(&opt, sizeof(opt), optval, optlen);
+		err = copy_safe_from_sockptr(&opt, sizeof(opt), optval, optlen);
 		if (err)
 			break;
 
@@ -970,7 +971,7 @@ static int l2cap_sock_setsockopt(struct socket *sock, int level, int optname,
 		break;
 
 	case BT_FLUSHABLE:
-		err = bt_copy_from_sockptr(&opt, sizeof(opt), optval, optlen);
+		err = copy_safe_from_sockptr(&opt, sizeof(opt), optval, optlen);
 		if (err)
 			break;
 
@@ -1004,7 +1005,7 @@ static int l2cap_sock_setsockopt(struct socket *sock, int level, int optname,
 
 		pwr.force_active = BT_POWER_FORCE_ACTIVE_ON;
 
-		err = bt_copy_from_sockptr(&pwr, sizeof(pwr), optval, optlen);
+		err = copy_safe_from_sockptr(&pwr, sizeof(pwr), optval, optlen);
 		if (err)
 			break;
 
@@ -1015,7 +1016,7 @@ static int l2cap_sock_setsockopt(struct socket *sock, int level, int optname,
 		break;
 
 	case BT_CHANNEL_POLICY:
-		err = bt_copy_from_sockptr(&opt, sizeof(opt), optval, optlen);
+		err = copy_safe_from_sockptr(&opt, sizeof(opt), optval, optlen);
 		if (err)
 			break;
 
@@ -1046,7 +1047,7 @@ static int l2cap_sock_setsockopt(struct socket *sock, int level, int optname,
 			break;
 		}
 
-		err = bt_copy_from_sockptr(&mtu, sizeof(mtu), optval, optlen);
+		err = copy_safe_from_sockptr(&mtu, sizeof(mtu), optval, optlen);
 		if (err)
 			break;
 
@@ -1076,7 +1077,8 @@ static int l2cap_sock_setsockopt(struct socket *sock, int level, int optname,
 			break;
 		}
 
-		err = bt_copy_from_sockptr(&mode, sizeof(mode), optval, optlen);
+		err = copy_safe_from_sockptr(&mode, sizeof(mode), optval,
+					     optlen);
 		if (err)
 			break;