netdev - [PATCH 3/4] batman-adv: Avoid sizeof on flexible structure

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Message-Id: <20210208165938.13262-4-sw@simonwunderlich.de>
Date:   Mon,  8 Feb 2021 17:59:37 +0100
From:   Simon Wunderlich <sw@...onwunderlich.de>
To:     kuba@...nel.org, 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 3/4] batman-adv: Avoid sizeof on flexible structure

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

The batadv_dhcp_packet is used to read in parts of the DHCP packet and
extract relevant information for the distributed arp table. But the
structure contained the flexible member "options" which is no where used in
the code.

A sizeof on this kind of type would return the size of everything except
the flexible member. But sparse will detect this kind of sizeof and warn
with

  warning: using sizeof on a flexible structure

This can be avoided by dropping the unused flexible member.

Signed-off-by: Sven Eckelmann <sven@...fation.org>
Signed-off-by: Simon Wunderlich <sw@...onwunderlich.de>
---
 net/batman-adv/distributed-arp-table.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/net/batman-adv/distributed-arp-table.c b/net/batman-adv/distributed-arp-table.c
index 01e0f84cb1ff..2542d85a59b4 100644
--- a/net/batman-adv/distributed-arp-table.c
+++ b/net/batman-adv/distributed-arp-table.c
@@ -87,7 +87,7 @@ struct batadv_dhcp_packet {
 	__u8 sname[64];
 	__u8 file[128];
 	__be32 magic;
-	__u8 options[];
+	/* __u8 options[]; */
 };
 
 #define BATADV_DHCP_YIADDR_LEN sizeof(((struct batadv_dhcp_packet *)0)->yiaddr)
-- 
2.20.1