l2tp: ppp: convert to getsockopt_iter

Convert PPPoL2TP 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 *opt
- Use opt->optlen for buffer length (input) and returned size (output)
- Use copy_to_iter() instead of put_user()/copy_to_user()

Acked-by: Stanislav Fomichev <sdf@fomichev.me>
Signed-off-by: Breno Leitao <leitao@debian.org>
Link: https://patch.msgid.link/20260520-getsock_four-v3-4-b8c0b16b7780@debian.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

diff --git a/net/l2tp/l2tp_ppp.c b/net/l2tp/l2tp_ppp.c
index 99d6582f41de2171557053d72bb7621c825822db..46143e882af5eb5cd814b3a160e0db83811231cb 100644 (file)
--- a/net/l2tp/l2tp_ppp.c
+++ b/net/l2tp/l2tp_ppp.c
@@ -59,6 +59,7 @@
 #include <linux/string.h>
 #include <linux/list.h>
 #include <linux/uaccess.h>
+#include <linux/uio.h>
 
 #include <linux/kernel.h>
 #include <linux/spinlock.h>
@@ -1317,7 +1318,7 @@ static int pppol2tp_session_getsockopt(struct sock *sk,
  * or the special tunnel type.
  */
 static int pppol2tp_getsockopt(struct socket *sock, int level, int optname,
-                              char __user *optval, int __user *optlen)
+                              sockopt_t *opt)
 {
        struct sock *sk = sock->sk;
        struct l2tp_session *session;
@@ -1328,9 +1329,7 @@ static int pppol2tp_getsockopt(struct socket *sock, int level, int optname,
        if (level != SOL_PPPOL2TP)
                return -EINVAL;
 
-       if (get_user(len, optlen))
-               return -EFAULT;
-
+       len = opt->optlen;
        if (len < 0)
                return -EINVAL;
 
@@ -1358,14 +1357,9 @@ static int pppol2tp_getsockopt(struct socket *sock, int level, int optname,
                        goto end_put_sess;
        }
 
-       err = -EFAULT;
-       if (put_user(len, optlen))
-               goto end_put_sess;
-
-       if (copy_to_user((void __user *)optval, &val, len))
-               goto end_put_sess;
-
-       err = 0;
+       opt->optlen = len;
+       if (copy_to_iter(&val, len, &opt->iter_out) != len)
+               err = -EFAULT;
 
 end_put_sess:
        l2tp_session_put(session);
@@ -1634,7 +1628,7 @@ static const struct proto_ops pppol2tp_ops = {
        .listen         = sock_no_listen,
        .shutdown       = sock_no_shutdown,
        .setsockopt     = pppol2tp_setsockopt,
-       .getsockopt     = pppol2tp_getsockopt,
+       .getsockopt_iter = pppol2tp_getsockopt,
        .sendmsg        = pppol2tp_sendmsg,
        .recvmsg        = pppol2tp_recvmsg,
        .mmap           = sock_no_mmap,