genetlink: fix family dump race

[android-x86/kernel.git] / net / netlink / genetlink.c

diff --git a/net/netlink/genetlink.c b/net/netlink/genetlink.c
index 512718a..f85f8a2 100644 (file)
--- a/net/netlink/genetlink.c
+++ b/net/netlink/genetlink.c
@@ -789,6 +789,10 @@ static int ctrl_dumpfamily(struct sk_buff *skb, struct netlink_callback *cb)
        struct net *net = sock_net(skb->sk);
        int chains_to_skip = cb->args[0];
        int fams_to_skip = cb->args[1];
+       bool need_locking = chains_to_skip || fams_to_skip;
+
+       if (need_locking)
+               genl_lock();
 
        for (i = chains_to_skip; i < GENL_FAM_TAB_SIZE; i++) {
                n = 0;
@@ -810,6 +814,9 @@ errout:
        cb->args[0] = i;
        cb->args[1] = n;
 
+       if (need_locking)
+               genl_unlock();
+
        return skb->len;
 }