From: Hangbin Liu <liuhangbin@gmail.com>
Date: Tue, 7 May 2019 09:11:18 +0000 (+0800)
Subject: fib_rules: return 0 directly if an exactly same rule exists when NLM_F_EXCL not supplied
X-Git-Tag: v4.9.177~11
X-Git-Url: https://www.infradead.org/git/?a=commitdiff_plain;h=1fff19a925e524556e85efcd728efad5274ce5b6;p=users%2Fdwmw2%2Flinux.git
fib_rules: return 0 directly if an exactly same rule exists when NLM_F_EXCL not supplied
[ Upstream commit e9919a24d3022f72bcadc407e73a6ef17093a849 ]
With commit 153380ec4b9 ("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: 153380ec4b9 ("fib_rules: Added NLM_F_EXCL support to fib_nl_newrule")
Reported-by: Thomas Haller <thaller@redhat.com>
Signed-off-by: Hangbin Liu <liuhangbin@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
diff --git a/net/core/fib_rules.c b/net/core/fib_rules.c
index be4629c344a6d..bb26457e8c21a 100644
--- a/net/core/fib_rules.c
+++ b/net/core/fib_rules.c
@@ -429,9 +429,9 @@ int fib_nl_newrule(struct sk_buff *skb, struct nlmsghdr *nlh)
if (rule->l3mdev && rule->table)
goto errout_free;
- 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;
}