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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org, Abhishek Shah <abhishek.shah@columbia.edu>,
        Herbert Xu <herbert@gondor.apana.org.au>,
        Steffen Klassert <steffen.klassert@secunet.com>,
        Sasha Levin <sashal@kernel.org>
Subject: [PATCH 4.9 03/31] af_key: Do not call xfrm_probe_algs in parallel
Date:   Fri,  2 Sep 2022 14:18:29 +0200
Message-Id: <20220902121356.874120507@linuxfoundation.org>
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From: Herbert Xu <herbert@gondor.apana.org.au>

[ Upstream commit ba953a9d89a00c078b85f4b190bc1dde66fe16b5 ]

When namespace support was added to xfrm/afkey, it caused the
previously single-threaded call to xfrm_probe_algs to become
multi-threaded.  This is buggy and needs to be fixed with a mutex.

Reported-by: Abhishek Shah <abhishek.shah@columbia.edu>
Fixes: 283bc9f35bbb ("xfrm: Namespacify xfrm state/policy locks")
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 net/key/af_key.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/net/key/af_key.c b/net/key/af_key.c
index 0737fc7b7ebdb..88d4a3a02ab72 100644
--- a/net/key/af_key.c
+++ b/net/key/af_key.c
@@ -1724,9 +1724,12 @@ static int pfkey_register(struct sock *sk, struct sk_buff *skb, const struct sad
 		pfk->registered |= (1<<hdr->sadb_msg_satype);
 	}
 
+	mutex_lock(&pfkey_mutex);
 	xfrm_probe_algs();
 
 	supp_skb = compose_sadb_supported(hdr, GFP_KERNEL | __GFP_ZERO);
+	mutex_unlock(&pfkey_mutex);
+
 	if (!supp_skb) {
 		if (hdr->sadb_msg_satype != SADB_SATYPE_UNSPEC)
 			pfk->registered &= ~(1<<hdr->sadb_msg_satype);
-- 
2.35.1