[PATCH net 4/9] batman-adv: dat: avoid unaligned fault in IP extraction

[Simon Wunderlich <sw@simonwunderlich.de>]

From: Sven Eckelmann <sven@narfation.org>

Independent of the alignment of the ARP packet in the SKB, either the
batadv_arp_ip_src or the batadv_arp_ip_dst will have an unaligned access
(on HW without native unaligned read support).

Use get_unaligned() to handle this properly on all architectures.

Cc: stable@vger.kernel.org
Reported-by: Sashiko <sashiko-bot@kernel.org>
Fixes: 5c3a0e553593 ("batman-adv: Distributed ARP Table - add ARP parsing functions")
Signed-off-by: Sven Eckelmann <sven@narfation.org>
Signed-off-by: Simon Wunderlich <sw@simonwunderlich.de>
---
 net/batman-adv/distributed-arp-table.c | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/net/batman-adv/distributed-arp-table.c b/net/batman-adv/distributed-arp-table.c
index 0d5a9cb0affeb..76fd23db926c7 100644
--- a/net/batman-adv/distributed-arp-table.c
+++ b/net/batman-adv/distributed-arp-table.c
@@ -316,7 +316,10 @@ static u8 *batadv_arp_hw_src(struct sk_buff *skb, int hdr_size)
  */
 static __be32 batadv_arp_ip_src(struct sk_buff *skb, int hdr_size)
 {
-	return *(__force __be32 *)(batadv_arp_hw_src(skb, hdr_size) + ETH_ALEN);
+	u8 *src = batadv_arp_hw_src(skb, hdr_size) + ETH_ALEN;
+	__be32 *ip = (__force __be32 *)src;
+
+	return get_unaligned(ip);
 }
 
 /**
@@ -341,8 +344,9 @@ static u8 *batadv_arp_hw_dst(struct sk_buff *skb, int hdr_size)
 static __be32 batadv_arp_ip_dst(struct sk_buff *skb, int hdr_size)
 {
 	u8 *dst = batadv_arp_hw_src(skb, hdr_size) + ETH_ALEN * 2 + 4;
+	__be32 *ip = (__force __be32 *)dst;
 
-	return *(__force __be32 *)dst;
+	return get_unaligned(ip);
 }
 
 /**
-- 
2.47.3