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authorPaolo Abeni <pabeni@redhat.com>2020-06-17 12:08:57 +0200
committerDavid S. Miller <davem@davemloft.net>2020-06-18 20:25:51 -0700
commit9e365ff576b7c1623bbc5ef31ec652c533e2f65e (patch)
tree5acc4e5efb1b182ea58308c74024884dbfe05860 /net
parent8fd4de1275580a1befa1456d1070eaf6489fb48f (diff)
mptcp: drop MP_JOIN request sock on syn cookies
Currently any MPTCP socket using syn cookies will fallback to TCP at 3rd ack time. In case of MP_JOIN requests, the RFC mandate closing the child and sockets, but the existing error paths do not handle the syncookie scenario correctly. Address the issue always forcing the child shutdown in case of MP_JOIN fallback. Fixes: ae2dd7164943 ("mptcp: handle tcp fallback when using syn cookies") Signed-off-by: Paolo Abeni <pabeni@redhat.com> Reviewed-by: Mat Martineau <mathew.j.martineau@linux.intel.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net')
-rw-r--r--net/mptcp/subflow.c18
1 files changed, 10 insertions, 8 deletions
diff --git a/net/mptcp/subflow.c b/net/mptcp/subflow.c
index 4068bdb2523b..3838a0b3a21f 100644
--- a/net/mptcp/subflow.c
+++ b/net/mptcp/subflow.c
@@ -431,22 +431,25 @@ static struct sock *subflow_syn_recv_sock(const struct sock *sk,
struct mptcp_subflow_context *listener = mptcp_subflow_ctx(sk);
struct mptcp_subflow_request_sock *subflow_req;
struct mptcp_options_received mp_opt;
- bool fallback_is_fatal = false;
+ bool fallback, fallback_is_fatal;
struct sock *new_msk = NULL;
- bool fallback = false;
struct sock *child;
pr_debug("listener=%p, req=%p, conn=%p", listener, req, listener->conn);
- /* we need later a valid 'mp_capable' value even when options are not
- * parsed
+ /* After child creation we must look for 'mp_capable' even when options
+ * are not parsed
*/
mp_opt.mp_capable = 0;
- if (tcp_rsk(req)->is_mptcp == 0)
+
+ /* hopefully temporary handling for MP_JOIN+syncookie */
+ subflow_req = mptcp_subflow_rsk(req);
+ fallback_is_fatal = subflow_req->mp_join;
+ fallback = !tcp_rsk(req)->is_mptcp;
+ if (fallback)
goto create_child;
/* if the sk is MP_CAPABLE, we try to fetch the client key */
- subflow_req = mptcp_subflow_rsk(req);
if (subflow_req->mp_capable) {
if (TCP_SKB_CB(skb)->seq != subflow_req->ssn_offset + 1) {
/* here we can receive and accept an in-window,
@@ -467,12 +470,11 @@ create_msk:
if (!new_msk)
fallback = true;
} else if (subflow_req->mp_join) {
- fallback_is_fatal = true;
mptcp_get_options(skb, &mp_opt);
if (!mp_opt.mp_join ||
!subflow_hmac_valid(req, &mp_opt)) {
SUBFLOW_REQ_INC_STATS(req, MPTCP_MIB_JOINACKMAC);
- return NULL;
+ fallback = true;
}
}