[PATCH 4.14 12/35] Revert "fib_rules: return 0 directly if an exactly same rule exists when NLM_F_EXCL not supplied"

From: Greg Kroah-Hartman
Date: Sun Jun 09 2019 - 13:23:05 EST


From: Hangbin Liu <liuhangbin@xxxxxxxxx>

[ Upstream commit 4970b42d5c362bf873982db7d93245c5281e58f4 ]

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@xxxxxxxxx>
Reported-by: Yaro Slav <yaro330@xxxxxxxxx>
Reported-by: Maciej Åenczykowski <zenczykowski@xxxxxxxxx>
Signed-off-by: Hangbin Liu <liuhangbin@xxxxxxxxx>
Reviewed-by: Nathan Chancellor <natechancellor@xxxxxxxxx>
Tested-by: Nathan Chancellor <natechancellor@xxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
net/core/fib_rules.c | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)

--- a/net/core/fib_rules.c
+++ b/net/core/fib_rules.c
@@ -563,9 +563,9 @@ int fib_nl_newrule(struct sk_buff *skb,
rule->uid_range = fib_kuid_range_unset;
}

- 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;
}