[PATCH net-next v2 5/6] Bluetooth: L2CAP: convert to getsockopt_iter

[Breno Leitao <leitao@debian.org>]

Convert L2CAP socket's getsockopt implementation to use the new
getsockopt_iter callback with sockopt_t.

Key changes:
- Replace (char __user *optval, int __user *optlen) with sockopt_t *sopt
- Use sopt->optlen for buffer length (input)
- Use copy_to_iter() instead of put_user()/copy_to_user()
- Add linux/uio.h for copy_to_iter()

The sockopt_t parameter is named sopt rather than opt to avoid
collision with the existing local u32 opt used by L2CAP_LM. The same
naming is reused for the new u32 helper in l2cap_sock_getsockopt(),
with mtu and mval helpers covering the u16 and u8 cases.

Signed-off-by: Breno Leitao <leitao@debian.org>
---
 net/bluetooth/l2cap_sock.c | 61 ++++++++++++++++++++++++++++------------------
 1 file changed, 37 insertions(+), 24 deletions(-)

diff --git a/net/bluetooth/l2cap_sock.c b/net/bluetooth/l2cap_sock.c
index cf590a67d3641..dede550d60319 100644
--- a/net/bluetooth/l2cap_sock.c
+++ b/net/bluetooth/l2cap_sock.c
@@ -31,6 +31,7 @@
 #include <linux/export.h>
 #include <linux/filter.h>
 #include <linux/sched/signal.h>
+#include <linux/uio.h>
 
 #include <net/bluetooth/bluetooth.h>
 #include <net/bluetooth/hci_core.h>
@@ -433,7 +434,7 @@ static int l2cap_get_mode(struct l2cap_chan *chan)
 }
 
 static int l2cap_sock_getsockopt_old(struct socket *sock, int optname,
-				     char __user *optval, int __user *optlen)
+				     sockopt_t *sopt)
 {
 	struct sock *sk = sock->sk;
 	struct l2cap_chan *chan = l2cap_pi(sk)->chan;
@@ -445,8 +446,7 @@ static int l2cap_sock_getsockopt_old(struct socket *sock, int optname,
 
 	BT_DBG("sk %p", sk);
 
-	if (get_user(len, optlen))
-		return -EFAULT;
+	len = sopt->optlen;
 
 	lock_sock(sk);
 
@@ -488,7 +488,7 @@ static int l2cap_sock_getsockopt_old(struct socket *sock, int optname,
 		BT_DBG("mode 0x%2.2x", chan->mode);
 
 		len = min(len, sizeof(opts));
-		if (copy_to_user(optval, (char *) &opts, len))
+		if (copy_to_iter(&opts, len, &sopt->iter_out) != len)
 			err = -EFAULT;
 
 		break;
@@ -520,7 +520,8 @@ static int l2cap_sock_getsockopt_old(struct socket *sock, int optname,
 		if (test_bit(FLAG_FORCE_RELIABLE, &chan->flags))
 			opt |= L2CAP_LM_RELIABLE;
 
-		if (put_user(opt, (u32 __user *) optval))
+		if (copy_to_iter(&opt, sizeof(opt), &sopt->iter_out) !=
+		    sizeof(opt))
 			err = -EFAULT;
 
 		break;
@@ -538,7 +539,7 @@ static int l2cap_sock_getsockopt_old(struct socket *sock, int optname,
 		memcpy(cinfo.dev_class, chan->conn->hcon->dev_class, 3);
 
 		len = min(len, sizeof(cinfo));
-		if (copy_to_user(optval, (char *) &cinfo, len))
+		if (copy_to_iter(&cinfo, len, &sopt->iter_out) != len)
 			err = -EFAULT;
 
 		break;
@@ -553,25 +554,26 @@ static int l2cap_sock_getsockopt_old(struct socket *sock, int optname,
 }
 
 static int l2cap_sock_getsockopt(struct socket *sock, int level, int optname,
-				 char __user *optval, int __user *optlen)
+				 sockopt_t *sopt)
 {
 	struct sock *sk = sock->sk;
 	struct l2cap_chan *chan = l2cap_pi(sk)->chan;
 	struct bt_security sec;
 	struct bt_power pwr;
-	u32 phys;
 	int len, mode, err = 0;
+	u32 opt;
+	u16 mtu;
+	u8 mval;
 
 	BT_DBG("sk %p", sk);
 
 	if (level == SOL_L2CAP)
-		return l2cap_sock_getsockopt_old(sock, optname, optval, optlen);
+		return l2cap_sock_getsockopt_old(sock, optname, sopt);
 
 	if (level != SOL_BLUETOOTH)
 		return -ENOPROTOOPT;
 
-	if (get_user(len, optlen))
-		return -EFAULT;
+	len = sopt->optlen;
 
 	lock_sock(sk);
 
@@ -595,7 +597,7 @@ static int l2cap_sock_getsockopt(struct socket *sock, int level, int optname,
 		}
 
 		len = min_t(unsigned int, len, sizeof(sec));
-		if (copy_to_user(optval, (char *) &sec, len))
+		if (copy_to_iter(&sec, len, &sopt->iter_out) != len)
 			err = -EFAULT;
 
 		break;
@@ -606,15 +608,17 @@ static int l2cap_sock_getsockopt(struct socket *sock, int level, int optname,
 			break;
 		}
 
-		if (put_user(test_bit(BT_SK_DEFER_SETUP, &bt_sk(sk)->flags),
-			     (u32 __user *) optval))
+		opt = test_bit(BT_SK_DEFER_SETUP, &bt_sk(sk)->flags);
+		if (copy_to_iter(&opt, sizeof(opt), &sopt->iter_out) !=
+		    sizeof(opt))
 			err = -EFAULT;
 
 		break;
 
 	case BT_FLUSHABLE:
-		if (put_user(test_bit(FLAG_FLUSHABLE, &chan->flags),
-			     (u32 __user *) optval))
+		opt = test_bit(FLAG_FLUSHABLE, &chan->flags);
+		if (copy_to_iter(&opt, sizeof(opt), &sopt->iter_out) !=
+		    sizeof(opt))
 			err = -EFAULT;
 
 		break;
@@ -629,13 +633,15 @@ static int l2cap_sock_getsockopt(struct socket *sock, int level, int optname,
 		pwr.force_active = test_bit(FLAG_FORCE_ACTIVE, &chan->flags);
 
 		len = min_t(unsigned int, len, sizeof(pwr));
-		if (copy_to_user(optval, (char *) &pwr, len))
+		if (copy_to_iter(&pwr, len, &sopt->iter_out) != len)
 			err = -EFAULT;
 
 		break;
 
 	case BT_CHANNEL_POLICY:
-		if (put_user(chan->chan_policy, (u32 __user *) optval))
+		opt = chan->chan_policy;
+		if (copy_to_iter(&opt, sizeof(opt), &sopt->iter_out) !=
+		    sizeof(opt))
 			err = -EFAULT;
 		break;
 
@@ -650,7 +656,9 @@ static int l2cap_sock_getsockopt(struct socket *sock, int level, int optname,
 			break;
 		}
 
-		if (put_user(chan->omtu, (u16 __user *) optval))
+		mtu = chan->omtu;
+		if (copy_to_iter(&mtu, sizeof(mtu), &sopt->iter_out) !=
+		    sizeof(mtu))
 			err = -EFAULT;
 		break;
 
@@ -660,7 +668,9 @@ static int l2cap_sock_getsockopt(struct socket *sock, int level, int optname,
 			break;
 		}
 
-		if (put_user(chan->imtu, (u16 __user *) optval))
+		mtu = chan->imtu;
+		if (copy_to_iter(&mtu, sizeof(mtu), &sopt->iter_out) !=
+		    sizeof(mtu))
 			err = -EFAULT;
 		break;
 
@@ -670,9 +680,10 @@ static int l2cap_sock_getsockopt(struct socket *sock, int level, int optname,
 			break;
 		}
 
-		phys = hci_conn_get_phy(chan->conn->hcon);
+		opt = hci_conn_get_phy(chan->conn->hcon);
 
-		if (put_user(phys, (u32 __user *) optval))
+		if (copy_to_iter(&opt, sizeof(opt), &sopt->iter_out) !=
+		    sizeof(opt))
 			err = -EFAULT;
 		break;
 
@@ -693,7 +704,9 @@ static int l2cap_sock_getsockopt(struct socket *sock, int level, int optname,
 			break;
 		}
 
-		if (put_user(mode, (u8 __user *) optval))
+		mval = mode;
+		if (copy_to_iter(&mval, sizeof(mval), &sopt->iter_out) !=
+		    sizeof(mval))
 			err = -EFAULT;
 		break;
 
@@ -2000,7 +2013,7 @@ static const struct proto_ops l2cap_sock_ops = {
 	.socketpair	= sock_no_socketpair,
 	.shutdown	= l2cap_sock_shutdown,
 	.setsockopt	= l2cap_sock_setsockopt,
-	.getsockopt	= l2cap_sock_getsockopt
+	.getsockopt_iter = l2cap_sock_getsockopt
 };
 
 static const struct net_proto_family l2cap_sock_family_ops = {

-- 
2.53.0-Meta