* [PATCH net] mptcp: fix data stream corruption
@ 2021-05-11 8:22 Paolo Abeni
2021-05-11 16:17 ` Mat Martineau
0 siblings, 1 reply; 4+ messages in thread
From: Paolo Abeni @ 2021-05-11 8:22 UTC (permalink / raw)
To: netdev
Cc: Mat Martineau, David S. Miller, Jakub Kicinski, mptcp, Maxim Galaganov
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(+)
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;
}
--
2.26.2
^ permalink raw reply related [flat|nested] 4+ messages in thread
* Re: [PATCH net] mptcp: fix data stream corruption
2021-05-11 8:22 [PATCH net] mptcp: fix data stream corruption Paolo Abeni
@ 2021-05-11 16:17 ` Mat Martineau
0 siblings, 0 replies; 4+ messages in thread
From: Mat Martineau @ 2021-05-11 16:17 UTC (permalink / raw)
To: Paolo Abeni
Cc: netdev, David S. Miller, Jakub Kicinski, mptcp, Maxim Galaganov
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")
?
-Mat
>
> 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;
> }
>
> --
> 2.26.2
>
>
>
--
Mat Martineau
Intel
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH net] mptcp: fix data stream corruption
@ 2021-05-11 16:17 ` Mat Martineau
0 siblings, 0 replies; 4+ messages in thread
From: Mat Martineau @ 2021-05-11 16:17 UTC (permalink / raw)
To: Paolo Abeni
Cc: netdev, David S. Miller, Jakub Kicinski, mptcp, Maxim Galaganov
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")
?
-Mat
>
> 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;
> }
>
> --
> 2.26.2
>
>
>
--
Mat Martineau
Intel
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH net] mptcp: fix data stream corruption
2021-05-11 16:17 ` Mat Martineau
(?)
@ 2021-05-11 17:10 ` Paolo Abeni
-1 siblings, 0 replies; 4+ messages in thread
From: Paolo Abeni @ 2021-05-11 17:10 UTC (permalink / raw)
To: Mat Martineau
Cc: netdev, David S. Miller, Jakub Kicinski, mptcp, Maxim Galaganov
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
^ permalink raw reply [flat|nested] 4+ messages in thread
end of thread, other threads:[~2021-05-11 17:10 UTC | newest]
Thread overview: 4+ messages (download: mbox.gz / follow: Atom feed)
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2021-05-11 8:22 [PATCH net] mptcp: fix data stream corruption Paolo Abeni
2021-05-11 16:17 ` Mat Martineau
2021-05-11 16:17 ` Mat Martineau
2021-05-11 17:10 ` Paolo Abeni
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