linux-kernel - [PATCH 4.19 219/245] batman-adv: bla: fix type misuse for backbone

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Message-Id: <20200929105957.635736871@linuxfoundation.org>
Date:   Tue, 29 Sep 2020 13:01:10 +0200
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org,
        Linus Lüssing <ll@...onwunderlich.de>,
        Sven Eckelmann <sven@...fation.org>,
        Sasha Levin <sashal@...nel.org>
Subject: [PATCH 4.19 219/245] batman-adv: bla: fix type misuse for backbone_gw hash indexing

From: Linus Lüssing <ll@...onwunderlich.de>

[ Upstream commit 097930e85f90f252c44dc0d084598265dd44ca48 ]

It seems that due to a copy & paste error the void pointer
in batadv_choose_backbone_gw() is cast to the wrong type.

Fixing this by using "struct batadv_bla_backbone_gw" instead of "struct
batadv_bla_claim" which better matches the caller's side.

For now it seems that we were lucky because the two structs both have
their orig/vid and addr/vid in the beginning. However I stumbled over
this issue when I was trying to add some debug variables in front of
"orig" in batadv_backbone_gw, which caused hash lookups to fail.

Fixes: 07568d0369f9 ("batman-adv: don't rely on positions in struct for hashing")
Signed-off-by: Linus Lüssing <ll@...onwunderlich.de>
Signed-off-by: Sven Eckelmann <sven@...fation.org>
Signed-off-by: Sasha Levin <sashal@...nel.org>
---
 net/batman-adv/bridge_loop_avoidance.c | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/net/batman-adv/bridge_loop_avoidance.c b/net/batman-adv/bridge_loop_avoidance.c
index 9b8bf06ccb613..e71a35a3950de 100644
--- a/net/batman-adv/bridge_loop_avoidance.c
+++ b/net/batman-adv/bridge_loop_avoidance.c
@@ -96,11 +96,12 @@ static inline u32 batadv_choose_claim(const void *data, u32 size)
  */
 static inline u32 batadv_choose_backbone_gw(const void *data, u32 size)
 {
-	const struct batadv_bla_claim *claim = (struct batadv_bla_claim *)data;
+	const struct batadv_bla_backbone_gw *gw;
 	u32 hash = 0;
 
-	hash = jhash(&claim->addr, sizeof(claim->addr), hash);
-	hash = jhash(&claim->vid, sizeof(claim->vid), hash);
+	gw = (struct batadv_bla_backbone_gw *)data;
+	hash = jhash(&gw->orig, sizeof(gw->orig), hash);
+	hash = jhash(&gw->vid, sizeof(gw->vid), hash);
 
 	return hash % size;
 }
-- 
2.25.1