From: Hangbin Liu <liuhangbin@gmail.com>
Date: Wed, 5 Jun 2019 04:27:14 +0000 (+0800)
Subject: Revert "fib_rules: return 0 directly if an exactly same rule exists when NLM_F_EXCL... 
X-Git-Tag: Ubuntu-5.2.0-15.16~1781^2~4
X-Git-Url: https://git.proxmox.com/?a=commitdiff_plain;h=4970b42d5c362bf873982db7d93245c5281e58f4;p=mirror_ubuntu-eoan-kernel.git

Revert "fib_rules: return 0 directly if an exactly same rule exists when NLM_F_EXCL not supplied"

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 43f0115cce9c..18f8dd8329ed 100644
--- 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;
 	}