net/ipv6: switch ipv6_flowlabel_opt to sockptr_t

Pass a sockptr_t to prepare for set_fs-less handling of the kernel
pointer from bpf-cgroup.

Note that the get case is pretty weird in that it actually copies data
back to userspace from setsockopt.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: David S. Miller <davem@davemloft.net>

include/net/ipv6.h

@@ -406,7 +406,7 @@ struct ipv6_txoptions *fl6_merge_options(struct ipv6_txoptions *opt_space,
 					 struct ip6_flowlabel *fl,
 					 struct ipv6_txoptions *fopt);
 void fl6_free_socklist(struct sock *sk);
-int ipv6_flowlabel_opt(struct sock *sk, char __user *optval, int optlen);
+int ipv6_flowlabel_opt(struct sock *sk, sockptr_t optval, int optlen);
 int ipv6_flowlabel_opt_get(struct sock *sk, struct in6_flowlabel_req *freq,
 			   int flags);
 int ip6_flowlabel_init(void);

net/ipv6/ip6_flowlabel.c

@@ -371,7 +371,7 @@ static int fl6_renew(struct ip6_flowlabel *fl, unsigned long linger, unsigned lo
 
 static struct ip6_flowlabel *
 fl_create(struct net *net, struct sock *sk, struct in6_flowlabel_req *freq,
-	  char __user *optval, int optlen, int *err_p)
+	  sockptr_t optval, int optlen, int *err_p)
 {
 	struct ip6_flowlabel *fl = NULL;
 	int olen;
@@ -401,7 +401,8 @@ fl_create(struct net *net, struct sock *sk, struct in6_flowlabel_req *freq,
 		memset(fl->opt, 0, sizeof(*fl->opt));
 		fl->opt->tot_len = sizeof(*fl->opt) + olen;
 		err = -EFAULT;
-		if (copy_from_user(fl->opt+1, optval+CMSG_ALIGN(sizeof(*freq)), olen))
+		sockptr_advance(optval, CMSG_ALIGN(sizeof(*freq)));
+		if (copy_from_sockptr(fl->opt + 1, optval, olen))
 			goto done;
 
 		msg.msg_controllen = olen;
@@ -604,7 +605,7 @@ static int ipv6_flowlabel_renew(struct sock *sk, struct in6_flowlabel_req *freq)
 }
 
 static int ipv6_flowlabel_get(struct sock *sk, struct in6_flowlabel_req *freq,
-		void __user *optval, int optlen)
+		sockptr_t optval, int optlen)
 {
 	struct ipv6_fl_socklist *sfl, *sfl1 = NULL;
 	struct ip6_flowlabel *fl, *fl1 = NULL;
@@ -702,8 +703,9 @@ static int ipv6_flowlabel_get(struct sock *sk, struct in6_flowlabel_req *freq,
 		goto recheck;
 
 	if (!freq->flr_label) {
-		if (copy_to_user(&((struct in6_flowlabel_req __user *) optval)->flr_label,
-				 &fl->label, sizeof(fl->label))) {
+		sockptr_advance(optval,
+				offsetof(struct in6_flowlabel_req, flr_label));
+		if (copy_to_sockptr(optval, &fl->label, sizeof(fl->label))) {
 			/* Intentionally ignore fault. */
 		}
 	}
@@ -716,13 +718,13 @@ static int ipv6_flowlabel_get(struct sock *sk, struct in6_flowlabel_req *freq,
 	return err;
 }
 
-int ipv6_flowlabel_opt(struct sock *sk, char __user *optval, int optlen)
+int ipv6_flowlabel_opt(struct sock *sk, sockptr_t optval, int optlen)
 {
 	struct in6_flowlabel_req freq;
 
 	if (optlen < sizeof(freq))
 		return -EINVAL;
-	if (copy_from_user(&freq, optval, sizeof(freq)))
+	if (copy_from_sockptr(&freq, optval, sizeof(freq)))
 		return -EFAULT;
 
 	switch (freq.flr_action) {

net/ipv6/ipv6_sockglue.c

@@ -929,7 +929,7 @@ static int do_ipv6_setsockopt(struct sock *sk, int level, int optname,
 		retv = 0;
 		break;
 	case IPV6_FLOWLABEL_MGR:
-		retv = ipv6_flowlabel_opt(sk, optval, optlen);
+		retv = ipv6_flowlabel_opt(sk, USER_SOCKPTR(optval), optlen);
 		break;
 	case IPV6_IPSEC_POLICY:
 	case IPV6_XFRM_POLICY: