This is a note to let you know that I've just added the patch titled
net/tls: missing received data after fast remote close
to the 5.9-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
net-tls-missing-received-data-after-fast-remote-close.patch
and it can be found in the queue-5.9 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From foo@baz Wed Dec 2 10:40:54 AM CET 2020
From: Vadim Fedorenko <vfedorenko@xxxxxxxx>
Date: Thu, 19 Nov 2020 18:59:48 +0300
Subject: net/tls: missing received data after fast remote close
From: Vadim Fedorenko <vfedorenko@xxxxxxxx>
[ Upstream commit 20ffc7adf53a5fd3d19751fbff7895bcca66686e ]
In case when tcp socket received FIN after some data and the
parser haven't started before reading data caller will receive
an empty buffer. This behavior differs from plain TCP socket and
leads to special treating in user-space.
The flow that triggers the race is simple. Server sends small
amount of data right after the connection is configured to use TLS
and closes the connection. In this case receiver sees TLS Handshake
data, configures TLS socket right after Change Cipher Spec record.
While the configuration is in process, TCP socket receives small
Application Data record, Encrypted Alert record and FIN packet. So
the TCP socket changes sk_shutdown to RCV_SHUTDOWN and sk_flag with
SK_DONE bit set. The received data is not parsed upon arrival and is
never sent to user-space.
Patch unpauses parser directly if we have unparsed data in tcp
receive queue.
Fixes: fcf4793e278e ("tls: check RCV_SHUTDOWN in tls_wait_data")
Signed-off-by: Vadim Fedorenko <vfedorenko@xxxxxxxx>
Link: https://lore.kernel.org/r/1605801588-12236-1-git-send-email-vfedorenko@xxxxxxxx
Signed-off-by: Jakub Kicinski <kuba@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
net/tls/tls_sw.c | 6 ++++++
1 file changed, 6 insertions(+)
--- a/net/tls/tls_sw.c
+++ b/net/tls/tls_sw.c
@@ -1295,6 +1295,12 @@ static struct sk_buff *tls_wait_data(str
return NULL;
}
+ if (!skb_queue_empty(&sk->sk_receive_queue)) {
+ __strp_unpause(&ctx->strp);
+ if (ctx->recv_pkt)
+ return ctx->recv_pkt;
+ }
+
if (sk->sk_shutdown & RCV_SHUTDOWN)
return NULL;
Patches currently in stable-queue which might be from vfedorenko@xxxxxxxx are
queue-5.9/net-tls-missing-received-data-after-fast-remote-close.patch
