6.1-stable review patch. If anyone has any objections, please let me know.
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From: Matthieu Baerts (NGI0) matttbe@kernel.org
commit efd340bf3d7779a3a8ec954d8ec0fb8a10f24982 upstream.
When sending an MP_JOIN + SYN + ACK, it is possible to mark the subflow as 'backup' by setting the flag with the same name. Before this patch, the backup was set if the other peer set it in its MP_JOIN + SYN request.
It is not correct: the backup flag should be set in the MPJ+SYN+ACK only if the host asks for it, and not mirroring what was done by the other peer. It is then required to have a dedicated bit for each direction, similar to what is done in the subflow context.
Fixes: f296234c98a8 ("mptcp: Add handling of incoming MP_JOIN requests") Cc: stable@vger.kernel.org Reviewed-by: Mat Martineau martineau@kernel.org Signed-off-by: Matthieu Baerts (NGI0) matttbe@kernel.org Signed-off-by: Paolo Abeni pabeni@redhat.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- net/mptcp/options.c | 2 +- net/mptcp/protocol.h | 1 + net/mptcp/subflow.c | 1 + 3 files changed, 3 insertions(+), 1 deletion(-)
--- a/net/mptcp/options.c +++ b/net/mptcp/options.c @@ -904,7 +904,7 @@ bool mptcp_synack_options(const struct r return true; } else if (subflow_req->mp_join) { opts->suboptions = OPTION_MPTCP_MPJ_SYNACK; - opts->backup = subflow_req->backup; + opts->backup = subflow_req->request_bkup; opts->join_id = subflow_req->local_id; opts->thmac = subflow_req->thmac; opts->nonce = subflow_req->local_nonce; --- a/net/mptcp/protocol.h +++ b/net/mptcp/protocol.h @@ -400,6 +400,7 @@ struct mptcp_subflow_request_sock { u16 mp_capable : 1, mp_join : 1, backup : 1, + request_bkup : 1, csum_reqd : 1, allow_join_id0 : 1; u8 local_id; --- a/net/mptcp/subflow.c +++ b/net/mptcp/subflow.c @@ -1876,6 +1876,7 @@ static void subflow_ulp_clone(const stru new_ctx->mp_join = 1; new_ctx->fully_established = 1; new_ctx->backup = subflow_req->backup; + new_ctx->request_bkup = subflow_req->request_bkup; WRITE_ONCE(new_ctx->remote_id, subflow_req->remote_id); new_ctx->token = subflow_req->token; new_ctx->thmac = subflow_req->thmac;