diff mbox series

[net,v6,03/10] ip6mr: Lock RCU before ip6mr_get_table() call in ip6mr_compat_ioctl()

Message ID 20241017174109.85717-4-stefan.wiehler@nokia.com (mailing list archive)
State Changes Requested
Delegated to: Netdev Maintainers
Headers show
Series Lock RCU before calling ip6mr_get_table() | expand

Checks

Context Check Description
netdev/tree_selection success Clearly marked for net
netdev/apply fail Patch does not apply to net-0

Commit Message

Stefan Wiehler Oct. 17, 2024, 5:37 p.m. UTC
When IPV6_MROUTE_MULTIPLE_TABLES is enabled, multicast routing tables
must be read under RCU or RTNL lock. Copy from user space must be
performed beforehand as we are not allowed to sleep under RCU lock.

Signed-off-by: Stefan Wiehler <stefan.wiehler@nokia.com>
Fixes: d1db275dd3f6 ("ipv6: ip6mr: support multiple tables")
---
 net/ipv6/ip6mr.c | 48 +++++++++++++++++++++++++++++++-----------------
 1 file changed, 31 insertions(+), 17 deletions(-)
diff mbox series

Patch

diff --git a/net/ipv6/ip6mr.c b/net/ipv6/ip6mr.c
index 19ce010016b9..968642bde8f8 100644
--- a/net/ipv6/ip6mr.c
+++ b/net/ipv6/ip6mr.c
@@ -1964,19 +1964,35 @@  int ip6mr_compat_ioctl(struct sock *sk, unsigned int cmd, void __user *arg)
 	struct mfc6_cache *c;
 	struct net *net = sock_net(sk);
 	struct mr_table *mrt;
-
-	mrt = ip6mr_get_table(net, raw6_sk(sk)->ip6mr_table ? : RT6_TABLE_DFLT);
-	if (!mrt)
-		return -ENOENT;
+	int err;
 
 	switch (cmd) {
 	case SIOCGETMIFCNT_IN6:
 		if (copy_from_user(&vr, arg, sizeof(vr)))
 			return -EFAULT;
-		if (vr.mifi >= mrt->maxvif)
-			return -EINVAL;
+		break;
+	case SIOCGETSGCNT_IN6:
+		if (copy_from_user(&sr, arg, sizeof(sr)))
+			return -EFAULT;
+		break;
+	default:
+		return -ENOIOCTLCMD;
+	}
+
+	rcu_read_lock();
+	mrt = ip6mr_get_table(net, raw6_sk(sk)->ip6mr_table ? : RT6_TABLE_DFLT);
+	if (!mrt) {
+		err = -ENOENT;
+		goto out;
+	}
+
+	switch (cmd) {
+	case SIOCGETMIFCNT_IN6:
+		if (vr.mifi >= mrt->maxvif) {
+			err = -EINVAL;
+			goto out;
+		}
 		vr.mifi = array_index_nospec(vr.mifi, mrt->maxvif);
-		rcu_read_lock();
 		vif = &mrt->vif_table[vr.mifi];
 		if (VIF_EXISTS(mrt, vr.mifi)) {
 			vr.icount = READ_ONCE(vif->pkt_in);
@@ -1989,13 +2005,9 @@  int ip6mr_compat_ioctl(struct sock *sk, unsigned int cmd, void __user *arg)
 				return -EFAULT;
 			return 0;
 		}
-		rcu_read_unlock();
-		return -EADDRNOTAVAIL;
+		err = -EADDRNOTAVAIL;
+		goto out;
 	case SIOCGETSGCNT_IN6:
-		if (copy_from_user(&sr, arg, sizeof(sr)))
-			return -EFAULT;
-
-		rcu_read_lock();
 		c = ip6mr_cache_find(mrt, &sr.src.sin6_addr, &sr.grp.sin6_addr);
 		if (c) {
 			sr.pktcnt = c->_c.mfc_un.res.pkt;
@@ -2007,11 +2019,13 @@  int ip6mr_compat_ioctl(struct sock *sk, unsigned int cmd, void __user *arg)
 				return -EFAULT;
 			return 0;
 		}
-		rcu_read_unlock();
-		return -EADDRNOTAVAIL;
-	default:
-		return -ENOIOCTLCMD;
+		err = -EADDRNOTAVAIL;
+		goto out;
 	}
+
+out:
+	rcu_read_unlock();
+	return err;
 }
 #endif