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From:   Chen Zhongjin <chenzhongjin@huawei.com>
To:     <linux-kernel@vger.kernel.org>, <netdev@vger.kernel.org>
CC:     <steffen.klassert@secunet.com>, <herbert@gondor.apana.org.au>,
        <davem@davemloft.net>, <yoshfuji@linux-ipv6.org>,
        <dsahern@kernel.org>, <edumazet@google.com>, <kuba@kernel.org>,
        <pabeni@redhat.com>, <mkubecek@suse.cz>, <chenzhongjin@huawei.com>
Subject: [PATCH net] xfrm: Fix ignored return value in xfrm6_init()
Date:   Thu, 3 Nov 2022 17:07:13 +0800
Message-ID: <20221103090713.188740-1-chenzhongjin@huawei.com>
MIME-Version: 1.0
Content-Type: text/plain
Precedence: bulk

When IPv6 module initializing in xfrm6_init(), register_pernet_subsys()
is possible to fail but its return value is ignored.

If IPv6 initialization fails later and xfrm6_fini() is called,
removing uninitialized list in xfrm6_net_ops will cause null-ptr-deref:

KASAN: null-ptr-deref in range [0x0000000000000008-0x000000000000000f]
CPU: 1 PID: 330 Comm: insmod
RIP: 0010:unregister_pernet_operations+0xc9/0x450
Call Trace:
 <TASK>
 unregister_pernet_subsys+0x31/0x3e
 xfrm6_fini+0x16/0x30 [ipv6]
 ip6_route_init+0xcd/0x128 [ipv6]
 inet6_init+0x29c/0x602 [ipv6]
 ...

Fix it by catching the error return value of register_pernet_subsys().

Fixes: 8d068875caca ("xfrm: make gc_thresh configurable in all namespaces")
Signed-off-by: Chen Zhongjin <chenzhongjin@huawei.com>
---
 net/ipv6/xfrm6_policy.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/net/ipv6/xfrm6_policy.c b/net/ipv6/xfrm6_policy.c
index 4a4b0e49ec92..ea435eba3053 100644
--- a/net/ipv6/xfrm6_policy.c
+++ b/net/ipv6/xfrm6_policy.c
@@ -287,9 +287,13 @@ int __init xfrm6_init(void)
 	if (ret)
 		goto out_state;
 
-	register_pernet_subsys(&xfrm6_net_ops);
+	ret = register_pernet_subsys(&xfrm6_net_ops);
+	if (ret)
+		goto out_protocol;
 out:
 	return ret;
+out_protocol:
+	xfrm6_protocol_fini();
 out_state:
 	xfrm6_state_fini();
 out_policy:
-- 
2.17.1