4.9-stable review patch. If anyone has any objections, please let me know. ------------------ From: Xin Long <lucien.xin@xxxxxxxxx> [ Upstream commit 6f29a130613191d3c6335169febe002cba00edf5 ] 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@xxxxxxxxx> Acked-by: Neil Horman <nhorman@xxxxxxxxxxxxx> Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx> Signed-off-by: Sasha Levin <alexander.levin@xxxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- net/sctp/socket.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) --- a/net/sctp/socket.c +++ b/net/sctp/socket.c @@ -235,8 +235,12 @@ static struct sctp_transport *sctp_addr_ 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,