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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, syzbot <syzkaller@googlegroups.com>,
        Steffen Klassert <steffen.klassert@secunet.com>,
        Herbert Xu <herbert@gondor.apana.org.au>,
        Cong Wang <xiyou.wangcong@gmail.com>
Subject: [PATCH 4.9 008/145] xfrm: check id proto in validate_tmpl()
Date:   Fri, 23 Feb 2018 19:25:14 +0100
Message-Id: <20180223170725.820280249@linuxfoundation.org>
In-Reply-To: <20180223170724.669759283@linuxfoundation.org>
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4.9-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Cong Wang <xiyou.wangcong@gmail.com>

commit 6a53b7593233ab9e4f96873ebacc0f653a55c3e1 upstream.

syzbot reported a kernel warning in xfrm_state_fini(), which
indicates that we have entries left in the list
net->xfrm.state_all whose proto is zero. And
xfrm_id_proto_match() doesn't consider them as a match with
IPSEC_PROTO_ANY in this case.

Proto with value 0 is probably not a valid value, at least
verify_newsa_info() doesn't consider it valid either.

This patch fixes it by checking the proto value in
validate_tmpl() and rejecting invalid ones, like what iproute2
does in xfrm_xfrmproto_getbyname().

Reported-by: syzbot <syzkaller@googlegroups.com>
Cc: Steffen Klassert <steffen.klassert@secunet.com>
Cc: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com>
Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 net/xfrm/xfrm_user.c |   15 +++++++++++++++
 1 file changed, 15 insertions(+)

--- a/net/xfrm/xfrm_user.c
+++ b/net/xfrm/xfrm_user.c
@@ -1406,6 +1406,21 @@ static int validate_tmpl(int nr, struct
 		default:
 			return -EINVAL;
 		}
+
+		switch (ut[i].id.proto) {
+		case IPPROTO_AH:
+		case IPPROTO_ESP:
+		case IPPROTO_COMP:
+#if IS_ENABLED(CONFIG_IPV6)
+		case IPPROTO_ROUTING:
+		case IPPROTO_DSTOPTS:
+#endif
+		case IPSEC_PROTO_ANY:
+			break;
+		default:
+			return -EINVAL;
+		}
+
 	}
 
 	return 0;