From 4f3951242ace5efc7131932e2e01e6ac6baed846 Mon Sep 17 00:00:00 2001
From: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>
Date: Fri, 5 Apr 2024 15:50:47 -0400
Subject: [PATCH] Bluetooth: L2CAP: Fix not validating setsockopt user input
Git-commit: 4f3951242ace5efc7131932e2e01e6ac6baed846
Patch-mainline: v6.9-rc4
References: git-fixes

Check user input length before copying data.

Fixes: 33575df7be67 ("Bluetooth: move l2cap_sock_setsockopt() to l2cap_sock.c")
Fixes: 3ee7b7cd8390 ("Bluetooth: Add BT_MODE socket option")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>
Acked-by: Takashi Iwai <tiwai@suse.de>

---
 net/bluetooth/l2cap_sock.c |   52 +++++++++++++++++----------------------------
 1 file changed, 20 insertions(+), 32 deletions(-)

--- a/net/bluetooth/l2cap_sock.c
+++ b/net/bluetooth/l2cap_sock.c
@@ -745,7 +745,7 @@ static int l2cap_sock_setsockopt_old(str
 	struct sock *sk = sock->sk;
 	struct l2cap_chan *chan = l2cap_pi(sk)->chan;
 	struct l2cap_options opts;
-	int len, err = 0;
+	int err = 0;
 	u32 opt;
 
 	BT_DBG("sk %p", sk);
@@ -772,11 +772,9 @@ static int l2cap_sock_setsockopt_old(str
 		opts.max_tx   = chan->max_tx;
 		opts.txwin_size = chan->tx_win;
 
-		len = min_t(unsigned int, sizeof(opts), optlen);
-		if (copy_from_sockptr(&opts, optval, len)) {
-			err = -EFAULT;
+		err = bt_copy_from_sockptr(&opts, sizeof(opts), optval, optlen);
+		if (err)
 			break;
-		}
 
 		if (opts.txwin_size > L2CAP_DEFAULT_EXT_WINDOW) {
 			err = -EINVAL;
@@ -819,10 +817,9 @@ static int l2cap_sock_setsockopt_old(str
 		break;
 
 	case L2CAP_LM:
-		if (copy_from_sockptr(&opt, optval, sizeof(u32))) {
-			err = -EFAULT;
+		err = bt_copy_from_sockptr(&opt, sizeof(opt), optval, optlen);
+		if (err)
 			break;
-		}
 
 		if (opt & L2CAP_LM_FIPS) {
 			err = -EINVAL;
@@ -903,7 +900,7 @@ static int l2cap_sock_setsockopt(struct
 	struct bt_security sec;
 	struct bt_power pwr;
 	struct l2cap_conn *conn;
-	int len, err = 0;
+	int err = 0;
 	u32 opt;
 	u16 mtu;
 	u8 mode;
@@ -929,11 +926,9 @@ static int l2cap_sock_setsockopt(struct
 
 		sec.level = BT_SECURITY_LOW;
 
-		len = min_t(unsigned int, sizeof(sec), optlen);
-		if (copy_from_sockptr(&sec, optval, len)) {
-			err = -EFAULT;
+		err = bt_copy_from_sockptr(&sec, sizeof(sec), optval, optlen);
+		if (err)
 			break;
-		}
 
 		if (sec.level < BT_SECURITY_LOW ||
 		    sec.level > BT_SECURITY_FIPS) {
@@ -978,10 +973,9 @@ static int l2cap_sock_setsockopt(struct
 			break;
 		}
 
-		if (copy_from_sockptr(&opt, optval, sizeof(u32))) {
-			err = -EFAULT;
+		err = bt_copy_from_sockptr(&opt, sizeof(opt), optval, optlen);
+		if (err)
 			break;
-		}
 
 		if (opt) {
 			set_bit(BT_SK_DEFER_SETUP, &bt_sk(sk)->flags);
@@ -993,10 +987,9 @@ static int l2cap_sock_setsockopt(struct
 		break;
 
 	case BT_FLUSHABLE:
-		if (copy_from_sockptr(&opt, optval, sizeof(u32))) {
-			err = -EFAULT;
+		err = bt_copy_from_sockptr(&opt, sizeof(opt), optval, optlen);
+		if (err)
 			break;
-		}
 
 		if (opt > BT_FLUSHABLE_ON) {
 			err = -EINVAL;
@@ -1028,11 +1021,9 @@ static int l2cap_sock_setsockopt(struct
 
 		pwr.force_active = BT_POWER_FORCE_ACTIVE_ON;
 
-		len = min_t(unsigned int, sizeof(pwr), optlen);
-		if (copy_from_sockptr(&pwr, optval, len)) {
-			err = -EFAULT;
+		err = bt_copy_from_sockptr(&pwr, sizeof(pwr), optval, optlen);
+		if (err)
 			break;
-		}
 
 		if (pwr.force_active)
 			set_bit(FLAG_FORCE_ACTIVE, &chan->flags);
@@ -1041,10 +1032,9 @@ static int l2cap_sock_setsockopt(struct
 		break;
 
 	case BT_CHANNEL_POLICY:
-		if (copy_from_sockptr(&opt, optval, sizeof(u32))) {
-			err = -EFAULT;
+		err = bt_copy_from_sockptr(&opt, sizeof(opt), optval, optlen);
+		if (err)
 			break;
-		}
 
 		if (opt > BT_CHANNEL_POLICY_AMP_PREFERRED) {
 			err = -EINVAL;
@@ -1089,10 +1079,9 @@ static int l2cap_sock_setsockopt(struct
 			break;
 		}
 
-		if (copy_from_sockptr(&mtu, optval, sizeof(u16))) {
-			err = -EFAULT;
+		err = bt_copy_from_sockptr(&mtu, sizeof(mtu), optval, optlen);
+		if (err)
 			break;
-		}
 
 		if (chan->mode == L2CAP_MODE_EXT_FLOWCTL &&
 		    sk->sk_state == BT_CONNECTED)
@@ -1120,10 +1109,9 @@ static int l2cap_sock_setsockopt(struct
 			break;
 		}
 
-		if (copy_from_sockptr(&mode, optval, sizeof(u8))) {
-			err = -EFAULT;
+		err = bt_copy_from_sockptr(&mode, sizeof(mode), optval, optlen);
+		if (err)
 			break;
-		}
 
 		BT_DBG("mode %u", mode);