fib_rules: return 0 directly if an exactly same rule exists when NLM_…

…F_EXCL not supplied [ Upstream commit e9919a24d3022f72bcadc407e73a6ef17093a849 ] With commit 153380e ("fib_rules: Added NLM_F_EXCL support to fib_nl_newrule") we now able to check if a rule already exists. But this only works with iproute2. For other tools like libnl, NetworkManager, it still could add duplicate rules with only NLM_F_CREATE flag, like [localhost ~ ]# ip rule 0: from all lookup local 32766: from all lookup main 32767: from all lookup default 100000: from 192.168.7.5 lookup 5 100000: from 192.168.7.5 lookup 5 As it doesn't make sense to create two duplicate rules, let's just return 0 if the rule exists. Fixes: 153380e ("fib_rules: Added NLM_F_EXCL support to fib_nl_newrule") Reported-by: Thomas Haller <[email protected]> Signed-off-by: Hangbin Liu <[email protected]> Signed-off-by: David S. Miller <[email protected]> Signed-off-by: Greg Kroah-Hartman <[email protected]>
akeromi · May 16, 2019 · 947fec6 · 947fec6
1 parent c7b5e55
commit 947fec6
Showing 1 changed file with 3 additions and 3 deletions.
diff --git a/net/core/fib_rules.c b/net/core/fib_rules.c
@@ -756,9 +756,9 @@ int fib_nl_newrule(struct sk_buff *skb, struct nlmsghdr *nlh,
 	if (err)
 		goto errout;
 
-	if ((nlh->nlmsg_flags & NLM_F_EXCL) &&
-	    rule_exists(ops, frh, tb, rule)) {
-		err = -EEXIST;
+	if (rule_exists(ops, frh, tb, rule)) {
+		if (nlh->nlmsg_flags & NLM_F_EXCL)
+			err = -EEXIST;
 		goto errout_free;
 	}