| Message ID | 95cee926051dae0afe4d39072f446e1cad17008a.1620720059.git.pabeni@redhat.com |
|---|---|
| State | New |
| Headers | show |
| Series | [net] mptcp: fix data stream corruption | expand |
On Tue, 2021-05-11 at 09:17 -0700, Mat Martineau wrote: > On Tue, 11 May 2021, Paolo Abeni wrote: > > > Maxim reported several issues when forcing a TCP transparent proxy > > to use the MPTCP protocol for the inbound connections. He also > > provided a clean reproducer. > > > > The problem boils down to 'mptcp_frag_can_collapse_to()' assuming > > that only MPTCP will use the given page_frag. > > > > If others - e.g. the plain TCP protocol - allocate page fragments, > > we can end-up re-using already allocated memory for mptcp_data_frag. > > > > Fix the issue ensuring that the to-be-expanded data fragment is > > located at the current page frag end. > > > > Closes: https://github.com/multipath-tcp/mptcp_net-next/issues/178 > > Reported-and-tested-by: Maxim Galaganov <max@internet.ru> > > Signed-off-by: Paolo Abeni <pabeni@redhat.com> > > --- > > net/mptcp/protocol.c | 6 ++++++ > > 1 file changed, 6 insertions(+) > > Hi Paolo - > > Should this also have a: > > Fixes: 18b683bff89d ("mptcp: queue data for mptcp level retransmission") > > ? Indeed! Will send a v2 soon. Thanks! Paolo
diff --git a/net/mptcp/protocol.c b/net/mptcp/protocol.c index 29a2d690d8d5..2d21a4793d9d 100644 --- a/net/mptcp/protocol.c +++ b/net/mptcp/protocol.c @@ -879,12 +879,18 @@ static bool mptcp_skb_can_collapse_to(u64 write_seq, !mpext->frozen; } +/* we can append data to the given data frag if: + * - there is space available in the backing page_frag + * - the data frag tail matches the current page_frag free offset + * - the data frag end sequence number matches the current write seq + */ static bool mptcp_frag_can_collapse_to(const struct mptcp_sock *msk, const struct page_frag *pfrag, const struct mptcp_data_frag *df) { return df && pfrag->page == df->page && pfrag->size - pfrag->offset > 0 && + pfrag->offset == (df->offset + df->data_len) && df->data_seq + df->data_len == msk->write_seq; }
Maxim reported several issues when forcing a TCP transparent proxy to use the MPTCP protocol for the inbound connections. He also provided a clean reproducer. The problem boils down to 'mptcp_frag_can_collapse_to()' assuming that only MPTCP will use the given page_frag. If others - e.g. the plain TCP protocol - allocate page fragments, we can end-up re-using already allocated memory for mptcp_data_frag. Fix the issue ensuring that the to-be-expanded data fragment is located at the current page frag end. Closes: https://github.com/multipath-tcp/mptcp_net-next/issues/178 Reported-and-tested-by: Maxim Galaganov <max@internet.ru> Signed-off-by: Paolo Abeni <pabeni@redhat.com> --- net/mptcp/protocol.c | 6 ++++++ 1 file changed, 6 insertions(+)