From: Paolo Abeni <pabeni@xxxxxxxxxx> [ Upstream commit 5957a8901db44c03540505ccedd95031c21ef2f2 ] The current implementation of 32 bit DSN expansion is buggy. After the previous patch, we can simply reuse the newly introduced helper to do the expansion safely. Closes: https://github.com/multipath-tcp/mptcp_net-next/issues/120 Fixes: 648ef4b88673 ("mptcp: Implement MPTCP receive path") Reviewed-by: Mat Martineau <mathew.j.martineau@xxxxxxxxxxxxxxx> Signed-off-by: Paolo Abeni <pabeni@xxxxxxxxxx> Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx> Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> --- net/mptcp/subflow.c | 17 +---------------- 1 file changed, 1 insertion(+), 16 deletions(-) diff --git a/net/mptcp/subflow.c b/net/mptcp/subflow.c index 3a396451d628..f5bb3a0e9975 100644 --- a/net/mptcp/subflow.c +++ b/net/mptcp/subflow.c @@ -775,15 +775,6 @@ enum mapping_status { MAPPING_DUMMY }; -static u64 expand_seq(u64 old_seq, u16 old_data_len, u64 seq) -{ - if ((u32)seq == (u32)old_seq) - return old_seq; - - /* Assume map covers data not mapped yet. */ - return seq | ((old_seq + old_data_len + 1) & GENMASK_ULL(63, 32)); -} - static void dbg_bad_map(struct mptcp_subflow_context *subflow, u32 ssn) { pr_debug("Bad mapping: ssn=%d map_seq=%d map_data_len=%d", @@ -907,13 +898,7 @@ static enum mapping_status get_mapping_status(struct sock *ssk, data_len--; } - if (!mpext->dsn64) { - map_seq = expand_seq(subflow->map_seq, subflow->map_data_len, - mpext->data_seq); - pr_debug("expanded seq=%llu", subflow->map_seq); - } else { - map_seq = mpext->data_seq; - } + map_seq = mptcp_expand_seq(READ_ONCE(msk->ack_seq), mpext->data_seq, mpext->dsn64); WRITE_ONCE(mptcp_sk(subflow->conn)->use_64bit_ack, !!mpext->dsn64); if (subflow->map_valid) { -- 2.30.2
