[IP]: Introduce ip_options_get_from_user

This variant is needed to satisfy sparse __user annotations.
Signed-off-by: Arnaldo Carvalho de Melo <acme@mandriva.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

include/net/ip.h

@@ -335,7 +335,10 @@ extern void ip_options_build(struct sk_buff *skb, struct ip_options *opt, u32 da
 extern int ip_options_echo(struct ip_options *dopt, struct sk_buff *skb);
 extern void ip_options_fragment(struct sk_buff *skb);
 extern int ip_options_compile(struct ip_options *opt, struct sk_buff *skb);
-extern int ip_options_get(struct ip_options **optp, unsigned char *data, int optlen, int user);
+extern int ip_options_get(struct ip_options **optp,
+			  unsigned char *data, int optlen);
+extern int ip_options_get_from_user(struct ip_options **optp,
+				    unsigned char __user *data, int optlen);
 extern void ip_options_undo(struct ip_options * opt);
 extern void ip_forward_options(struct sk_buff *skb);
 extern int ip_options_rcv_srr(struct sk_buff *skb);

net/ipv4/ip_options.c

@@ -489,23 +489,18 @@ void ip_options_undo(struct ip_options * opt)
 	}
 }
 
-int ip_options_get(struct ip_options **optp, unsigned char *data, int optlen, int user)
+static struct ip_options *ip_options_get_alloc(const int optlen)
 {
-	struct ip_options *opt;
+	struct ip_options *opt = kmalloc(sizeof(*opt) + ((optlen + 3) & ~3),
+					 GFP_KERNEL);
+	if (opt)
+		memset(opt, 0, sizeof(*opt));
+	return opt;
+}
 
-	opt = kmalloc(sizeof(struct ip_options)+((optlen+3)&~3), GFP_KERNEL);
-	if (!opt)
-		return -ENOMEM;
-	memset(opt, 0, sizeof(struct ip_options));
-	if (optlen) {
-		if (user) {
-			if (copy_from_user(opt->__data, data, optlen)) {
-				kfree(opt);
-				return -EFAULT;
-			}
-		} else
-			memcpy(opt->__data, data, optlen);
-	}
+static int ip_options_get_finish(struct ip_options **optp,
+				 struct ip_options *opt, int optlen)
+{
 	while (optlen & 3)
 		opt->__data[optlen++] = IPOPT_END;
 	opt->optlen = optlen;
@@ -521,6 +516,30 @@ int ip_options_get(struct ip_options **optp, unsigned char *data, int optlen, in
 	return 0;
 }
 
+int ip_options_get_from_user(struct ip_options **optp, unsigned char __user *data, int optlen)
+{
+	struct ip_options *opt = ip_options_get_alloc(optlen);
+
+	if (!opt)
+		return -ENOMEM;
+	if (optlen && copy_from_user(opt->__data, data, optlen)) {
+		kfree(opt);
+		return -EFAULT;
+	}
+	return ip_options_get_finish(optp, opt, optlen);
+}
+
+int ip_options_get(struct ip_options **optp, unsigned char *data, int optlen)
+{
+	struct ip_options *opt = ip_options_get_alloc(optlen);
+
+	if (!opt)
+		return -ENOMEM;
+	if (optlen)
+		memcpy(opt->__data, data, optlen);
+	return ip_options_get_finish(optp, opt, optlen);
+}
+
 void ip_forward_options(struct sk_buff *skb)
 {
 	struct   ip_options * opt	= &(IPCB(skb)->opt);

net/ipv4/ip_sockglue.c

@@ -153,7 +153,7 @@ int ip_cmsg_send(struct msghdr *msg, struct ipcm_cookie *ipc)
 		switch (cmsg->cmsg_type) {
 		case IP_RETOPTS:
 			err = cmsg->cmsg_len - CMSG_ALIGN(sizeof(struct cmsghdr));
-			err = ip_options_get(&ipc->opt, CMSG_DATA(cmsg), err < 40 ? err : 40, 0);
+			err = ip_options_get(&ipc->opt, CMSG_DATA(cmsg), err < 40 ? err : 40);
 			if (err)
 				return err;
 			break;
@@ -425,7 +425,7 @@ int ip_setsockopt(struct sock *sk, int level, int optname, char __user *optval,
 			struct ip_options * opt = NULL;
 			if (optlen > 40 || optlen < 0)
 				goto e_inval;
-			err = ip_options_get(&opt, optval, optlen, 1);
+			err = ip_options_get_from_user(&opt, optval, optlen);
 			if (err)
 				break;
 			if (sk->sk_type == SOCK_STREAM) {