On Wed, Jun 24, 2020 at 05:34:18PM -0300, Marcelo Ricardo Leitner wrote:
> 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 the issue for me.
Tested-by: Corey Minyard <cminyard@xxxxxxxxxx>
Thanks a bunch.
-corey
>
> Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
> Reported-by: Corey Minyard <cminyard@xxxxxxxxxx>
> Signed-off-by: Marcelo Ricardo Leitner <marcelo.leitner@xxxxxxxxx>
> ---
> include/net/sctp/constants.h | 8 +++++---
> net/sctp/associola.c | 5 ++++-
> net/sctp/bind_addr.c | 1 +
> net/sctp/protocol.c | 3 ++-
> 4 files changed, 12 insertions(+), 5 deletions(-)
>
> diff --git a/include/net/sctp/constants.h b/include/net/sctp/constants.h
> index 15b4d9aec7ff278e67a7183f10c14be237227d6b..122d9e2d8dfde33b787d575fc42d454732550698 100644
> --- a/include/net/sctp/constants.h
> +++ b/include/net/sctp/constants.h
> @@ -353,11 +353,13 @@ 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 72315137d7e7f20d5182291ef4b01102f030078b..8d735461fa196567ab19c583703aad098ef8e240 100644
> --- a/net/sctp/associola.c
> +++ b/net/sctp/associola.c
> @@ -1565,12 +1565,15 @@ void sctp_assoc_rwnd_decrease(struct sctp_association *asoc, unsigned int len)
> int sctp_assoc_set_bind_addr_from_ep(struct sctp_association *asoc,
> enum sctp_scope 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 53bc61537f44f4e766c417fcef72234df52ecd04..701c5a4e441d9c248df9472f22db5b78987f9e44 100644
> --- a/net/sctp/bind_addr.c
> +++ b/net/sctp/bind_addr.c
> @@ -461,6 +461,7 @@ 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 092d1afdee0d23cd974210839310fbf406dd443f..cde29f3c7fb3c40ee117636fa3b4b7f0a03e4fba 100644
> --- a/net/sctp/protocol.c
> +++ b/net/sctp/protocol.c
> @@ -148,7 +148,8 @@ int sctp_copy_local_addr_list(struct net *net, struct sctp_bind_addr *bp,
> * sock as well as the remote peer.
> */
> if (addr->a.sa.sa_family == AF_INET &&
> - !(copy_flags & SCTP_ADDR4_PEERSUPP))
> + (!(copy_flags & SCTP_ADDR4_ALLOWED) ||
> + !(copy_flags & SCTP_ADDR4_PEERSUPP)))
> continue;
> if (addr->a.sa.sa_family == AF_INET6 &&
> (!(copy_flags & SCTP_ADDR6_ALLOWED) ||
> --
> 2.25.4
>
