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@xxxxxxxxxxxxxxx
Reviewed-by: Mat Martineau <martineau@xxxxxxxxxx>
Signed-off-by: Matthieu Baerts (NGI0) <matttbe@xxxxxxxxxx>
Signed-off-by: Paolo Abeni <pabeni@xxxxxxxxxx>
[ Conflicts in subflow.c, because the context has changed in commit
4cf86ae84c71 ("mptcp: strict local address ID selection"), and in
commit 967d3c27127e ("mptcp: fix data races on remote_id"), which are
not in this version. These commits are unrelated to this
modification.
Same in protocol.h, with commit bab6b88e0560 ("mptcp: add
allow_join_id0 in mptcp_out_options"). ]
Signed-off-by: Matthieu Baerts (NGI0) <matttbe@xxxxxxxxxx>
---
net/mptcp/options.c | 2 +-
net/mptcp/protocol.h | 3 ++-
net/mptcp/subflow.c | 1 +
3 files changed, 4 insertions(+), 2 deletions(-)
diff --git a/net/mptcp/options.c b/net/mptcp/options.c
index c389d7e47135..f7a91266d5a9 100644
--- a/net/mptcp/options.c
+++ b/net/mptcp/options.c
@@ -708,7 +708,7 @@ bool mptcp_synack_options(const struct request_sock *req, unsigned int *size,
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;
diff --git a/net/mptcp/protocol.h b/net/mptcp/protocol.h
index 3e5af8397434..b5978bb4022f 100644
--- a/net/mptcp/protocol.h
+++ b/net/mptcp/protocol.h
@@ -261,7 +261,8 @@ struct mptcp_subflow_request_sock {
struct tcp_request_sock sk;
u16 mp_capable : 1,
mp_join : 1,
- backup : 1;
+ backup : 1,
+ request_bkup : 1;
u8 local_id;
u8 remote_id;
u64 local_key;
diff --git a/net/mptcp/subflow.c b/net/mptcp/subflow.c
index 823a92b21c6c..a59c731d7fed 100644
--- a/net/mptcp/subflow.c
+++ b/net/mptcp/subflow.c
@@ -1395,6 +1395,7 @@ static void subflow_ulp_clone(const struct request_sock *req,
new_ctx->mp_join = 1;
new_ctx->fully_established = 1;
new_ctx->backup = subflow_req->backup;
+ new_ctx->request_bkup = subflow_req->request_bkup;
new_ctx->local_id = subflow_req->local_id;
new_ctx->remote_id = subflow_req->remote_id;
new_ctx->token = subflow_req->token;
--
2.45.2
