netdev - [PATCH net] sctp: sctp_addr_id2transport should verify the addr before looking up assoc

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Date:   Tue, 24 Jan 2017 14:01:53 +0800
From:   Xin Long <lucien.xin@...il.com>
To:     network dev <netdev@...r.kernel.org>, linux-sctp@...r.kernel.org
Cc:     davem@...emloft.net,
        Marcelo Ricardo Leitner <marcelo.leitner@...il.com>,
        Neil Horman <nhorman@...driver.com>
Subject: [PATCH net] sctp: sctp_addr_id2transport should verify the addr before looking up assoc

sctp_addr_id2transport is a function for sockopt to look up assoc by
address. As the address is from userspace, it can be a v4-mapped v6
address. But in sctp protocol stack, it always handles a v4-mapped
v6 address as a v4 address. So it's necessary to convert it to a v4
address before looking up assoc by address.

This patch is to fix it by calling sctp_verify_addr in which it can do
this conversion before calling sctp_endpoint_lookup_assoc, just like
what sctp_sendmsg and __sctp_connect do for the address from users.

Signed-off-by: Xin Long <lucien.xin@...il.com>
---
 net/sctp/socket.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/net/sctp/socket.c b/net/sctp/socket.c
index 318c678..37eeab7 100644
--- a/net/sctp/socket.c
+++ b/net/sctp/socket.c
@@ -235,8 +235,12 @@ static struct sctp_transport *sctp_addr_id2transport(struct sock *sk,
 					      sctp_assoc_t id)
 {
 	struct sctp_association *addr_asoc = NULL, *id_asoc = NULL;
-	struct sctp_transport *transport;
+	struct sctp_af *af = sctp_get_af_specific(addr->ss_family);
 	union sctp_addr *laddr = (union sctp_addr *)addr;
+	struct sctp_transport *transport;
+
+	if (sctp_verify_addr(sk, laddr, af->sockaddr_len))
+		return NULL;

 	addr_asoc = sctp_endpoint_lookup_assoc(sctp_sk(sk)->ep,
 					       laddr,
-- 
2.1.0