netdev - [PATCH 5/7] batman-adv: Fix netlink dumping of BLA claims

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Message-Id: <20180302175142.11838-6-sw@simonwunderlich.de>
Date:   Fri,  2 Mar 2018 18:51:40 +0100
From:   Simon Wunderlich <sw@...onwunderlich.de>
To:     davem@...emloft.net
Cc:     netdev@...r.kernel.org, b.a.t.m.a.n@...ts.open-mesh.org,
        Sven Eckelmann <sven@...fation.org>,
        Simon Wunderlich <sw@...onwunderlich.de>
Subject: [PATCH 5/7] batman-adv: Fix netlink dumping of BLA claims

From: Sven Eckelmann <sven@...fation.org>

The function batadv_bla_claim_dump_bucket must be able to handle
non-complete dumps of a single bucket. It tries to do that by saving the
latest dumped index in *idx_skip to inform the caller about the current
state.

But the caller only assumes that buckets were not completely dumped when
the return code is non-zero. This function must therefore also return a
non-zero index when the dumping of an entry failed. Otherwise the caller
will just skip all remaining buckets.

And the function must also reset *idx_skip back to zero when it finished a
bucket. Otherwise it will skip the same number of entries in the next
bucket as the previous one had.

Fixes: 04f3f5bf1883 ("batman-adv: add B.A.T.M.A.N. Dump BLA claims via netlink")
Reported-by: Linus Lüssing <linus.luessing@...3.blue>
Signed-off-by: Sven Eckelmann <sven@...fation.org>
Signed-off-by: Simon Wunderlich <sw@...onwunderlich.de>
---
 net/batman-adv/bridge_loop_avoidance.c | 11 +++++++----
 1 file changed, 7 insertions(+), 4 deletions(-)

diff --git a/net/batman-adv/bridge_loop_avoidance.c b/net/batman-adv/bridge_loop_avoidance.c
index fad47853ad3c..20b548ea5a0a 100644
--- a/net/batman-adv/bridge_loop_avoidance.c
+++ b/net/batman-adv/bridge_loop_avoidance.c
@@ -2161,22 +2161,25 @@ batadv_bla_claim_dump_bucket(struct sk_buff *msg, u32 portid, u32 seq,
 {
 	struct batadv_bla_claim *claim;
 	int idx = 0;
+	int ret = 0;
 
 	rcu_read_lock();
 	hlist_for_each_entry_rcu(claim, head, hash_entry) {
 		if (idx++ < *idx_skip)
 			continue;
-		if (batadv_bla_claim_dump_entry(msg, portid, seq,
-						primary_if, claim)) {
+
+		ret = batadv_bla_claim_dump_entry(msg, portid, seq,
+						  primary_if, claim);
+		if (ret) {
 			*idx_skip = idx - 1;
 			goto unlock;
 		}
 	}
 
-	*idx_skip = idx;
+	*idx_skip = 0;
 unlock:
 	rcu_read_unlock();
-	return 0;
+	return ret;
 }
 
 /**
-- 
2.11.0