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 <luiz.von.dentz@intel.com>
Reviewed-by: David Wei <dw@davidwei.uk>
Signed-off-by: Michal Luczaj <mhal@rbox.co>
Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>

5 files changed, 33 insertions, 31 deletions

diff --git a/net/bluetooth/hci_sock.c b/net/bluetooth/hci_sock.c
index 2272e1849ebd..022b86797acd 100644
--- a/net/bluetooth/hci_sock.c
+++ b/net/bluetooth/hci_sock.c
@@ -1926,7 +1926,7 @@ drop:
 }
 
 static int hci_sock_setsockopt_old(struct socket *sock, int level, int optname,
-				   sockptr_t optval, unsigned int len)
+				   sockptr_t optval, unsigned int optlen)
 {
 	struct hci_ufilter uf = { .opcode = 0 };
 	struct sock *sk = sock->sk;
@@ -1943,7 +1943,7 @@ static int hci_sock_setsockopt_old(struct socket *sock, int level, int optname,
 
 	switch (optname) {
 	case HCI_DATA_DIR:
-		err = bt_copy_from_sockptr(&opt, sizeof(opt), optval, len);
+		err = copy_safe_from_sockptr(&opt, sizeof(opt), optval, optlen);
 		if (err)
 			break;
 
@@ -1954,7 +1954,7 @@ static int hci_sock_setsockopt_old(struct socket *sock, int level, int optname,
 		break;
 
 	case HCI_TIME_STAMP:
-		err = bt_copy_from_sockptr(&opt, sizeof(opt), optval, len);
+		err = copy_safe_from_sockptr(&opt, sizeof(opt), optval, optlen);
 		if (err)
 			break;
 
@@ -1974,7 +1974,7 @@ static int hci_sock_setsockopt_old(struct socket *sock, int level, int optname,
 			uf.event_mask[1] = *((u32 *) f->event_mask + 1);
 		}
 
-		err = bt_copy_from_sockptr(&uf, sizeof(uf), optval, len);
+		err = copy_safe_from_sockptr(&uf, sizeof(uf), optval, optlen);
 		if (err)
 			break;
 
@@ -2005,7 +2005,7 @@ done:
 }
 
 static int hci_sock_setsockopt(struct socket *sock, int level, int optname,
-			       sockptr_t optval, unsigned int len)
+			       sockptr_t optval, unsigned int optlen)
 {
 	struct sock *sk = sock->sk;
 	int err = 0;
@@ -2015,7 +2015,7 @@ static int hci_sock_setsockopt(struct socket *sock, int level, int optname,
 
 	if (level == SOL_HCI)
 		return hci_sock_setsockopt_old(sock, level, optname, optval,
-					       len);
+					       optlen);
 
 	if (level != SOL_BLUETOOTH)
 		return -ENOPROTOOPT;
@@ -2035,7 +2035,7 @@ static int hci_sock_setsockopt(struct socket *sock, int level, int optname,
 			goto done;
 		}
 
-		err = bt_copy_from_sockptr(&opt, sizeof(opt), optval, len);
+		err = copy_safe_from_sockptr(&opt, sizeof(opt), optval, optlen);
 		if (err)
 			break;
 
diff --git a/net/bluetooth/iso.c b/net/bluetooth/iso.c
index 1b40fd2b2f02..695b56091e18 100644
--- a/net/bluetooth/iso.c
+++ b/net/bluetooth/iso.c
@@ -1566,7 +1566,7 @@ static int iso_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;
 
@@ -1577,7 +1577,7 @@ static int iso_sock_setsockopt(struct socket *sock, int level, int optname,
 		break;
 
 	case BT_PKT_STATUS:
-		err = bt_copy_from_sockptr(&opt, sizeof(opt), optval, optlen);
+		err = copy_safe_from_sockptr(&opt, sizeof(opt), optval, optlen);
 		if (err)
 			break;
 
@@ -1596,7 +1596,7 @@ static int iso_sock_setsockopt(struct socket *sock, int level, int optname,
 			break;
 		}
 
-		err = bt_copy_from_sockptr(&qos, sizeof(qos), optval, optlen);
+		err = copy_safe_from_sockptr(&qos, sizeof(qos), optval, optlen);
 		if (err)
 			break;
 
@@ -1617,8 +1617,8 @@ static int iso_sock_setsockopt(struct socket *sock, int level, int optname,
 			break;
 		}
 
-		err = bt_copy_from_sockptr(iso_pi(sk)->base, optlen, optval,
-					   optlen);
+		err = copy_safe_from_sockptr(iso_pi(sk)->base, optlen, optval,
+					     optlen);
 		if (err)
 			break;
 
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;
 
diff --git a/net/bluetooth/rfcomm/sock.c b/net/bluetooth/rfcomm/sock.c
index 40766f8119ed..913402806fa0 100644
--- a/net/bluetooth/rfcomm/sock.c
+++ b/net/bluetooth/rfcomm/sock.c
@@ -629,10 +629,9 @@ static int rfcomm_sock_setsockopt_old(struct socket *sock, int optname,
 
 	switch (optname) {
 	case RFCOMM_LM:
-		if (bt_copy_from_sockptr(&opt, sizeof(opt), optval, optlen)) {
-			err = -EFAULT;
+		err = copy_safe_from_sockptr(&opt, sizeof(opt), optval, optlen);
+		if (err)
 			break;
-		}
 
 		if (opt & RFCOMM_LM_FIPS) {
 			err = -EINVAL;
@@ -685,7 +684,7 @@ static int rfcomm_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;
 
@@ -703,7 +702,7 @@ static int rfcomm_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;
 
diff --git a/net/bluetooth/sco.c b/net/bluetooth/sco.c
index 78f7bca24487..7eb8d3e04ec4 100644
--- a/net/bluetooth/sco.c
+++ b/net/bluetooth/sco.c
@@ -896,7 +896,7 @@ static int sco_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;
 
@@ -915,8 +915,8 @@ static int sco_sock_setsockopt(struct socket *sock, int level, int optname,
 
 		voice.setting = sco_pi(sk)->setting;
 
-		err = bt_copy_from_sockptr(&voice, sizeof(voice), optval,
-					   optlen);
+		err = copy_safe_from_sockptr(&voice, sizeof(voice), optval,
+					     optlen);
 		if (err)
 			break;
 
@@ -941,7 +941,7 @@ static int sco_sock_setsockopt(struct socket *sock, int level, int optname,
 		break;
 
 	case BT_PKT_STATUS:
-		err = bt_copy_from_sockptr(&opt, sizeof(opt), optval, optlen);
+		err = copy_safe_from_sockptr(&opt, sizeof(opt), optval, optlen);
 		if (err)
 			break;
 
@@ -984,7 +984,8 @@ static int sco_sock_setsockopt(struct socket *sock, int level, int optname,
 			break;
 		}
 
-		err = bt_copy_from_sockptr(buffer, optlen, optval, optlen);
+		err = copy_struct_from_sockptr(buffer, sizeof(buffer), optval,
+					       optlen);
 		if (err) {
 			hci_dev_put(hdev);
 			break;