Revert "fib_rules: return 0 directly if an exactly same rule exists when NLM_F_EXCL...

This reverts commit e9919a24d3022f72bcadc407e73a6ef17093a849.

Nathan reported the new behaviour breaks Android, as Android just add
new rules and delete old ones.

If we return 0 without adding dup rules, Android will remove the new
added rules and causing system to soft-reboot.

Fixes: e9919a24d302 ("fib_rules: return 0 directly if an exactly same rule exists when NLM_F_EXCL not supplied")
Reported-by: Nathan Chancellor <natechancellor@gmail.com>
Reported-by: Yaro Slav <yaro330@gmail.com>
Reported-by: Maciej Żenczykowski <zenczykowski@gmail.com>
Signed-off-by: Hangbin Liu <liuhangbin@gmail.com>
Reviewed-by: Nathan Chancellor <natechancellor@gmail.com>
Tested-by: Nathan Chancellor <natechancellor@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/net/core/fib_rules.c b/net/core/fib_rules.c
index 43f0115cce9cb43dbe2e6788a18b7671f404b056..18f8dd8329ede7cd78a9abe9c49f1b8c0e881a6b 100644 (file)
--- a/net/core/fib_rules.c
+++ b/net/core/fib_rules.c
@@ -757,9 +757,9 @@ int fib_nl_newrule(struct sk_buff *skb, struct nlmsghdr *nlh,
        if (err)
                goto errout;
 
-       if (rule_exists(ops, frh, tb, rule)) {
-               if (nlh->nlmsg_flags & NLM_F_EXCL)
-                       err = -EEXIST;
+       if ((nlh->nlmsg_flags & NLM_F_EXCL) &&
+           rule_exists(ops, frh, tb, rule)) {
+               err = -EEXIST;
                goto errout_free;
        }