kcm: convert to getsockopt_iter

Convert KCM 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()
- Add linux/uio.h for copy_to_iter()

Signed-off-by: Breno Leitao <leitao@debian.org>
Link: https://patch.msgid.link/20260507-getsock_two-v2-4-5873111d9c12@debian.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

diff --git a/net/kcm/kcmsock.c b/net/kcm/kcmsock.c
index 3912e75079f5eb7f95405570da7a8db63a9d7b2d..b273213cc68d1c98a377f8e7efb03561e0d42d69 100644 (file)
--- a/net/kcm/kcmsock.c
+++ b/net/kcm/kcmsock.c
@@ -24,6 +24,7 @@
 #include <linux/workqueue.h>
 #include <linux/syscalls.h>
 #include <linux/sched/signal.h>
+#include <linux/uio.h>
 
 #include <net/kcm.h>
 #include <net/netns/generic.h>
@@ -1167,7 +1168,7 @@ static int kcm_setsockopt(struct socket *sock, int level, int optname,
 }
 
 static int kcm_getsockopt(struct socket *sock, int level, int optname,
-                         char __user *optval, int __user *optlen)
+                         sockopt_t *opt)
 {
        struct kcm_sock *kcm = kcm_sk(sock->sk);
        int val, len;
@@ -1175,9 +1176,7 @@ static int kcm_getsockopt(struct socket *sock, int level, int optname,
        if (level != SOL_KCM)
                return -ENOPROTOOPT;
 
-       if (get_user(len, optlen))
-               return -EFAULT;
-
+       len = opt->optlen;
        if (len < 0)
                return -EINVAL;
 
@@ -1191,9 +1190,8 @@ static int kcm_getsockopt(struct socket *sock, int level, int optname,
                return -ENOPROTOOPT;
        }
 
-       if (put_user(len, optlen))
-               return -EFAULT;
-       if (copy_to_user(optval, &val, len))
+       opt->optlen = len;
+       if (copy_to_iter(&val, len, &opt->iter_out) != len)
                return -EFAULT;
        return 0;
 }
@@ -1755,7 +1753,7 @@ static const struct proto_ops kcm_dgram_ops = {
        .listen =       sock_no_listen,
        .shutdown =     sock_no_shutdown,
        .setsockopt =   kcm_setsockopt,
-       .getsockopt =   kcm_getsockopt,
+       .getsockopt_iter = kcm_getsockopt,
        .sendmsg =      kcm_sendmsg,
        .recvmsg =      kcm_recvmsg,
        .mmap =         sock_no_mmap,
@@ -1776,7 +1774,7 @@ static const struct proto_ops kcm_seqpacket_ops = {
        .listen =       sock_no_listen,
        .shutdown =     sock_no_shutdown,
        .setsockopt =   kcm_setsockopt,
-       .getsockopt =   kcm_getsockopt,
+       .getsockopt_iter = kcm_getsockopt,
        .sendmsg =      kcm_sendmsg,
        .recvmsg =      kcm_recvmsg,
        .mmap =         sock_no_mmap,