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Subject[PATCH 4.4 089/135] sctp: Don't advertise IPv4 addresses if ipv6only is set on the socket
Date
From: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>

[ Upstream commit 471e39df96b9a4c4ba88a2da9e25a126624d7a9c ]

If a socket is set ipv6only, it will still send IPv4 addresses in the
INIT and INIT_ACK packets. This potentially misleads the peer into using
them, which then would cause association termination.

The fix is to not add IPv4 addresses to ipv6only sockets.

Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Reported-by: Corey Minyard <cminyard@mvista.com>
Signed-off-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Tested-by: Corey Minyard <cminyard@mvista.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
include/net/sctp/constants.h | 8 +++++---
net/sctp/associola.c | 5 ++++-
net/sctp/bind_addr.c | 1 +
net/sctp/protocol.c | 1 +
4 files changed, 11 insertions(+), 4 deletions(-)

diff --git a/include/net/sctp/constants.h b/include/net/sctp/constants.h
index 8c337cd0e1e45..bf03bab93d9e9 100644
--- a/include/net/sctp/constants.h
+++ b/include/net/sctp/constants.h
@@ -357,11 +357,13 @@ typedef enum {
ipv4_is_anycast_6to4(a))

/* Flags used for the bind address copy functions. */
-#define SCTP_ADDR6_ALLOWED 0x00000001 /* IPv6 address is allowed by
+#define SCTP_ADDR4_ALLOWED 0x00000001 /* IPv4 address is allowed by
local sock family */
-#define SCTP_ADDR4_PEERSUPP 0x00000002 /* IPv4 address is supported by
+#define SCTP_ADDR6_ALLOWED 0x00000002 /* IPv6 address is allowed by
+ local sock family */
+#define SCTP_ADDR4_PEERSUPP 0x00000004 /* IPv4 address is supported by
peer */
-#define SCTP_ADDR6_PEERSUPP 0x00000004 /* IPv6 address is supported by
+#define SCTP_ADDR6_PEERSUPP 0x00000008 /* IPv6 address is supported by
peer */

/* Reasons to retransmit. */
diff --git a/net/sctp/associola.c b/net/sctp/associola.c
index f24d31f12cb44..aa38578fdfcd9 100644
--- a/net/sctp/associola.c
+++ b/net/sctp/associola.c
@@ -1575,12 +1575,15 @@ void sctp_assoc_rwnd_decrease(struct sctp_association *asoc, unsigned int len)
int sctp_assoc_set_bind_addr_from_ep(struct sctp_association *asoc,
sctp_scope_t scope, gfp_t gfp)
{
+ struct sock *sk = asoc->base.sk;
int flags;

/* Use scoping rules to determine the subset of addresses from
* the endpoint.
*/
- flags = (PF_INET6 == asoc->base.sk->sk_family) ? SCTP_ADDR6_ALLOWED : 0;
+ flags = (PF_INET6 == sk->sk_family) ? SCTP_ADDR6_ALLOWED : 0;
+ if (!inet_v6_ipv6only(sk))
+ flags |= SCTP_ADDR4_ALLOWED;
if (asoc->peer.ipv4_address)
flags |= SCTP_ADDR4_PEERSUPP;
if (asoc->peer.ipv6_address)
diff --git a/net/sctp/bind_addr.c b/net/sctp/bind_addr.c
index 871cdf9567e6b..664215448d09f 100644
--- a/net/sctp/bind_addr.c
+++ b/net/sctp/bind_addr.c
@@ -449,6 +449,7 @@ static int sctp_copy_one_addr(struct net *net, struct sctp_bind_addr *dest,
* well as the remote peer.
*/
if ((((AF_INET == addr->sa.sa_family) &&
+ (flags & SCTP_ADDR4_ALLOWED) &&
(flags & SCTP_ADDR4_PEERSUPP))) ||
(((AF_INET6 == addr->sa.sa_family) &&
(flags & SCTP_ADDR6_ALLOWED) &&
diff --git a/net/sctp/protocol.c b/net/sctp/protocol.c
index 9c6c42fd9f8af..b0e401dfe1600 100644
--- a/net/sctp/protocol.c
+++ b/net/sctp/protocol.c
@@ -210,6 +210,7 @@ int sctp_copy_local_addr_list(struct net *net, struct sctp_bind_addr *bp,
* sock as well as the remote peer.
*/
if ((((AF_INET == addr->a.sa.sa_family) &&
+ (copy_flags & SCTP_ADDR4_ALLOWED) &&
(copy_flags & SCTP_ADDR4_PEERSUPP))) ||
(((AF_INET6 == addr->a.sa.sa_family) &&
(copy_flags & SCTP_ADDR6_ALLOWED) &&
--
2.25.1
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