Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67;
From:   Al Viro <viro@ZenIV.linux.org.uk>
To:     netdev@vger.kernel.org
Cc:     "David S. Miller" <davem@davemloft.net>,
        Linus Torvalds <torvalds@linux-foundation.org>,
        linux-kernel@vger.kernel.org, Christoph Hellwig <hch@lst.de>,
        Al Viro <viro@zeniv.linux.org.uk>
Subject: [PATCH 03/10] ip_rt_ioctl(): take copyin to caller
Date:   Thu, 18 Jan 2018 19:37:48 +0000
Message-Id: <20180118193755.19997-3-viro@ZenIV.linux.org.uk>
In-Reply-To: <20180118193755.19997-1-viro@ZenIV.linux.org.uk>
References: <20180118193156.GC13338@ZenIV.linux.org.uk>
 <20180118193755.19997-1-viro@ZenIV.linux.org.uk>
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

From: Al Viro <viro@zeniv.linux.org.uk>

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
---
 include/net/route.h     |  2 +-
 net/ipv4/af_inet.c      |  7 ++++++-
 net/ipv4/fib_frontend.c |  8 ++------
 net/ipv4/ipconfig.c     | 13 +------------
 4 files changed, 10 insertions(+), 20 deletions(-)

diff --git a/include/net/route.h b/include/net/route.h
index d538e6db1afe..1eb9ce470e25 100644
--- a/include/net/route.h
+++ b/include/net/route.h
@@ -217,7 +217,7 @@ unsigned int inet_addr_type_dev_table(struct net *net,
 				      const struct net_device *dev,
 				      __be32 addr);
 void ip_rt_multicast_event(struct in_device *);
-int ip_rt_ioctl(struct net *, unsigned int cmd, void __user *arg);
+int ip_rt_ioctl(struct net *, unsigned int cmd, struct rtentry *rt);
 void ip_rt_get_source(u8 *src, struct sk_buff *skb, struct rtable *rt);
 struct rtable *rt_dst_alloc(struct net_device *dev,
 			     unsigned int flags, u16 type,
diff --git a/net/ipv4/af_inet.c b/net/ipv4/af_inet.c
index 1c2bfee2e249..c24008daa3d8 100644
--- a/net/ipv4/af_inet.c
+++ b/net/ipv4/af_inet.c
@@ -874,6 +874,7 @@ int inet_ioctl(struct socket *sock, unsigned int cmd, unsigned long arg)
 	struct net *net = sock_net(sk);
 	void __user *p = (void __user *)arg;
 	struct ifreq ifr;
+	struct rtentry rt;
 
 	switch (cmd) {
 	case SIOCGSTAMP:
@@ -884,8 +885,12 @@ int inet_ioctl(struct socket *sock, unsigned int cmd, unsigned long arg)
 		break;
 	case SIOCADDRT:
 	case SIOCDELRT:
+		if (copy_from_user(&rt, p, sizeof(struct rtentry)))
+			return -EFAULT;
+		err = ip_rt_ioctl(net, cmd, &rt);
+		break;
 	case SIOCRTMSG:
-		err = ip_rt_ioctl(net, cmd, (void __user *)arg);
+		err = -EINVAL;
 		break;
 	case SIOCDARP:
 	case SIOCGARP:
diff --git a/net/ipv4/fib_frontend.c b/net/ipv4/fib_frontend.c
index 08259d078b1c..f05afaf3235c 100644
--- a/net/ipv4/fib_frontend.c
+++ b/net/ipv4/fib_frontend.c
@@ -587,10 +587,9 @@ static int rtentry_to_fib_config(struct net *net, int cmd, struct rtentry *rt,
  * Handle IP routing ioctl calls.
  * These are used to manipulate the routing tables
  */
-int ip_rt_ioctl(struct net *net, unsigned int cmd, void __user *arg)
+int ip_rt_ioctl(struct net *net, unsigned int cmd, struct rtentry *rt)
 {
 	struct fib_config cfg;
-	struct rtentry rt;
 	int err;
 
 	switch (cmd) {
@@ -599,11 +598,8 @@ int ip_rt_ioctl(struct net *net, unsigned int cmd, void __user *arg)
 		if (!ns_capable(net->user_ns, CAP_NET_ADMIN))
 			return -EPERM;
 
-		if (copy_from_user(&rt, arg, sizeof(rt)))
-			return -EFAULT;
-
 		rtnl_lock();
-		err = rtentry_to_fib_config(net, cmd, &rt, &cfg);
+		err = rtentry_to_fib_config(net, cmd, rt, &cfg);
 		if (err == 0) {
 			struct fib_table *tb;
 
diff --git a/net/ipv4/ipconfig.c b/net/ipv4/ipconfig.c
index 6895fff609b1..5f396afaa08d 100644
--- a/net/ipv4/ipconfig.c
+++ b/net/ipv4/ipconfig.c
@@ -340,17 +340,6 @@ static int __init ic_dev_ioctl(unsigned int cmd, struct ifreq *arg)
 	return res;
 }
 
-static int __init ic_route_ioctl(unsigned int cmd, struct rtentry *arg)
-{
-	int res;
-
-	mm_segment_t oldfs = get_fs();
-	set_fs(get_ds());
-	res = ip_rt_ioctl(&init_net, cmd, (void __user *) arg);
-	set_fs(oldfs);
-	return res;
-}
-
 /*
  *	Set up interface addresses and routes.
  */
@@ -412,7 +401,7 @@ static int __init ic_setup_routes(void)
 		set_sockaddr((struct sockaddr_in *) &rm.rt_genmask, 0, 0);
 		set_sockaddr((struct sockaddr_in *) &rm.rt_gateway, ic_gateway, 0);
 		rm.rt_flags = RTF_UP | RTF_GATEWAY;
-		if ((err = ic_route_ioctl(SIOCADDRT, &rm)) < 0) {
+		if ((err = ip_rt_ioctl(&init_net, SIOCADDRT, &rm)) < 0) {
 			pr_err("IP-Config: Cannot add default route (%d)\n",
 			       err);
 			return -1;
-- 
2.11.0