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From: Qingfang Deng <dqfext@gmail.com>
To: stable@vger.kernel.org
Cc: Qingfang Deng <qingfang.deng@siflower.com.cn>,
	"David S. Miller" <davem@davemloft.net>,
	Eric Dumazet <edumazet@google.com>,
	Jakub Kicinski <kuba@kernel.org>,
	Paolo Abeni <pabeni@redhat.com>,
	Masahide NAKAMURA <nakam@linux-ipv6.org>,
	YOSHIFUJI Hideaki <yoshfuji@linux-ipv6.org>,
	Ville Nuorvala <vnuorval@tcs.hut.fi>,
	netdev@vger.kernel.org,
	linux-kernel@vger.kernel.org
Subject: [PATCH 4.19.y] neighbour: fix unaligned access to pneigh_entry
Date: Wed,  5 Jun 2024 10:29:16 +0800
Message-Id: <20240605022916.247882-1-dqfext@gmail.com>
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From: Qingfang Deng <qingfang.deng@siflower.com.cn>

[ Upstream commit ed779fe4c9b5a20b4ab4fd6f3e19807445bb78c7 ]

After the blamed commit, the member key is longer 4-byte aligned. On
platforms that do not support unaligned access, e.g., MIPS32R2 with
unaligned_action set to 1, this will trigger a crash when accessing
an IPv6 pneigh_entry, as the key is cast to an in6_addr pointer.

Change the type of the key to u32 to make it aligned.

Fixes: 62dd93181aaa ("[IPV6] NDISC: Set per-entry is_router flag in Proxy NA.")
Signed-off-by: Qingfang Deng <qingfang.deng@siflower.com.cn>
---
 include/net/neighbour.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/include/net/neighbour.h b/include/net/neighbour.h
index e58ef9e338de..4c53e51f0799 100644
--- a/include/net/neighbour.h
+++ b/include/net/neighbour.h
@@ -172,7 +172,7 @@ struct pneigh_entry {
 	possible_net_t		net;
 	struct net_device	*dev;
 	u8			flags;
-	u8			key[0];
+	u32			key[0];
 };
 
 /*
-- 
2.34.1