From c5715eb7792149be764c7083fc46d6dc0081e12a Mon Sep 17 00:00:00 2001
From: Theo Buehler <tb@cvs.openbsd.org>
Date: Mon, 30 Apr 2018 19:07:45 +0000
Subject: Reduce the scope of the NET_LOCK() in in_control(). Two functions
 were protected: mrt_ioctl() and in_ioctl(). The former has no other callers
 and only needs a read lock. The latter will need refactoring to reduce the
 lock's scope further. In a first step, establish a single exit point and
 protect most of the function body with the NET_LOCK() while removing the
 NET_LOCK() from a handful of callers.

suggested by & ok mpi, ok visa
---
 sys/netinet/in.c | 82 ++++++++++++++++++++++++++++++++++----------------------
 1 file changed, 50 insertions(+), 32 deletions(-)

(limited to 'sys/netinet/in.c')

diff --git a/sys/netinet/in.c b/sys/netinet/in.c
index eda6ac60b97..32d5f6777ad 100644
--- a/sys/netinet/in.c
+++ b/sys/netinet/in.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: in.c,v 1.149 2018/04/24 19:53:38 florian Exp $	*/
+/*	$OpenBSD: in.c,v 1.150 2018/04/30 19:07:44 tb Exp $	*/
 /*	$NetBSD: in.c,v 1.26 1996/02/13 23:41:39 christos Exp $	*/
 
 /*
@@ -187,7 +187,6 @@ in_control(struct socket *so, u_long cmd, caddr_t data, struct ifnet *ifp)
 	int privileged;
 	int error;
 
-	NET_LOCK();
 	privileged = 0;
 	if ((so->so_state & SS_PRIV) != 0)
 		privileged++;
@@ -204,7 +203,6 @@ in_control(struct socket *so, u_long cmd, caddr_t data, struct ifnet *ifp)
 		break;
 	}
 
-	NET_UNLOCK();
 	return error;
 }
 
@@ -216,13 +214,13 @@ in_ioctl(u_long cmd, caddr_t data, struct ifnet *ifp, int privileged)
 	struct in_ifaddr *ia = NULL;
 	struct in_aliasreq *ifra = (struct in_aliasreq *)data;
 	struct sockaddr_in oldaddr;
-	int error;
+	int error = 0;
 	int newifaddr;
 
 	if (ifp == NULL)
 		return (ENXIO);
 
-	NET_ASSERT_LOCKED();
+	NET_LOCK();
 
 	TAILQ_FOREACH(ifa, &ifp->if_addrlist, ifa_list) {
 		if (ifa->ifa_addr->sa_family == AF_INET) {
@@ -244,12 +242,16 @@ in_ioctl(u_long cmd, caddr_t data, struct ifnet *ifp, int privileged)
 			}
 			ia = ifatoia(ifa);
 		}
-		if (cmd == SIOCDIFADDR && ia == NULL)
-			return (EADDRNOTAVAIL);
+		if (cmd == SIOCDIFADDR && ia == NULL) {
+			error = EADDRNOTAVAIL;
+			goto err;
+		}
 		/* FALLTHROUGH */
 	case SIOCSIFADDR:
-		if (!privileged)
-			return (EPERM);
+		if (!privileged) {
+			error = EPERM;
+			goto err;
+		}
 
 		if (ia == NULL) {
 			ia = malloc(sizeof *ia, M_IFADDR, M_WAITOK | M_ZERO);
@@ -273,8 +275,10 @@ in_ioctl(u_long cmd, caddr_t data, struct ifnet *ifp, int privileged)
 	case SIOCSIFNETMASK:
 	case SIOCSIFDSTADDR:
 	case SIOCSIFBRDADDR:
-		if (!privileged)
-			return (EPERM);
+		if (!privileged) {
+			error = EPERM;
+			goto err;
+		}
 		/* FALLTHROUGH */
 
 	case SIOCGIFADDR:
@@ -291,8 +295,10 @@ in_ioctl(u_long cmd, caddr_t data, struct ifnet *ifp, int privileged)
 				}
 			}
 		}
-		if (ia == NULL)
-			return (EADDRNOTAVAIL);
+		if (ia == NULL) {
+			error = EADDRNOTAVAIL;
+			goto err;
+		}
 		break;
 	}
 	switch (cmd) {
@@ -302,14 +308,18 @@ in_ioctl(u_long cmd, caddr_t data, struct ifnet *ifp, int privileged)
 		break;
 
 	case SIOCGIFBRDADDR:
-		if ((ifp->if_flags & IFF_BROADCAST) == 0)
-			return (EINVAL);
+		if ((ifp->if_flags & IFF_BROADCAST) == 0) {
+			error = EINVAL;
+			break;
+		}
 		*satosin(&ifr->ifr_dstaddr) = ia->ia_broadaddr;
 		break;
 
 	case SIOCGIFDSTADDR:
-		if ((ifp->if_flags & IFF_POINTOPOINT) == 0)
-			return (EINVAL);
+		if ((ifp->if_flags & IFF_POINTOPOINT) == 0) {
+			error = EINVAL;
+			break;
+		}
 		*satosin(&ifr->ifr_dstaddr) = ia->ia_dstaddr;
 		break;
 
@@ -318,31 +328,36 @@ in_ioctl(u_long cmd, caddr_t data, struct ifnet *ifp, int privileged)
 		break;
 
 	case SIOCSIFDSTADDR:
-		if ((ifp->if_flags & IFF_POINTOPOINT) == 0)
-			return (EINVAL);
+		if ((ifp->if_flags & IFF_POINTOPOINT) == 0) {
+			error = EINVAL;
+			break;
+		}
 		oldaddr = ia->ia_dstaddr;
 		ia->ia_dstaddr = *satosin(&ifr->ifr_dstaddr);
 		error = (*ifp->if_ioctl)(ifp, SIOCSIFDSTADDR, (caddr_t)ia);
 		if (error) {
 			ia->ia_dstaddr = oldaddr;
-			return (error);
+			break;
 		}
 		in_scrubhost(ia, &oldaddr);
 		in_addhost(ia, &ia->ia_dstaddr);
 		break;
 
 	case SIOCSIFBRDADDR:
-		if ((ifp->if_flags & IFF_BROADCAST) == 0)
-			return (EINVAL);
+		if ((ifp->if_flags & IFF_BROADCAST) == 0) {
+			error = EINVAL;
+			break;
+		}
 		ifa_update_broadaddr(ifp, &ia->ia_ifa, &ifr->ifr_broadaddr);
 		break;
 
 	case SIOCSIFADDR:
 		in_ifscrub(ifp, ia);
 		error = in_ifinit(ifp, ia, satosin(&ifr->ifr_addr), newifaddr);
-		if (!error)
-			dohooks(ifp->if_addrhooks, 0);
-		return (error);
+		if (error)
+			break;
+		dohooks(ifp->if_addrhooks, 0);
+		break;
 
 	case SIOCSIFNETMASK:
 		ia->ia_netmask = ia->ia_sockmask.sin_addr.s_addr =
@@ -352,8 +367,6 @@ in_ioctl(u_long cmd, caddr_t data, struct ifnet *ifp, int privileged)
 	case SIOCAIFADDR: {
 		int needinit = 0;
 
-		error = 0;
-
 		if (ia->ia_addr.sin_family == AF_INET) {
 			if (ifra->ifra_addr.sin_len == 0)
 				ifra->ifra_addr = ia->ia_addr;
@@ -384,9 +397,10 @@ in_ioctl(u_long cmd, caddr_t data, struct ifnet *ifp, int privileged)
 		if (ifra->ifra_addr.sin_family == AF_INET && needinit) {
 			error = in_ifinit(ifp, ia, &ifra->ifra_addr, newifaddr);
 		}
-		if (!error)
-			dohooks(ifp->if_addrhooks, 0);
-		return (error);
+		if (error)
+			break;
+		dohooks(ifp->if_addrhooks, 0);
+		break;
 		}
 	case SIOCDIFADDR:
 		/*
@@ -400,9 +414,13 @@ in_ioctl(u_long cmd, caddr_t data, struct ifnet *ifp, int privileged)
 		break;
 
 	default:
-		return (EOPNOTSUPP);
+		error = EOPNOTSUPP;
+		break;
 	}
-	return (0);
+
+err:
+	NET_UNLOCK();
+	return (error);
 }
 /*
  * Delete any existing route for an interface.
-- 
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