diff mbox series

[6.2,0776/1001] cifs: dont try to use rdma offload on encrypted connections

Message ID 20230307170055.423579951@linuxfoundation.org
State New
Headers show
Series None | expand

Commit Message

Greg KH March 7, 2023, 4:59 p.m. UTC 
From: Stefan Metzmacher <metze@samba.org>

commit 3891f6c7655a39065e44980f51ba46bb32be3133 upstream.

The aim of using encryption on a connection is to keep
the data confidential, so we must not use plaintext rdma offload
for that data!

It seems that current windows servers and ksmbd would allow
this, but that's no reason to expose the users data in plaintext!
And servers hopefully reject this in future.

Note modern windows servers support signed or encrypted offload,
see MS-SMB2 2.2.3.1.6 SMB2_RDMA_TRANSFORM_CAPABILITIES, but we don't
support that yet.

Signed-off-by: Stefan Metzmacher <metze@samba.org>
Cc: Steve French <smfrench@gmail.com>
Cc: Tom Talpey <tom@talpey.com>
Cc: Long Li <longli@microsoft.com>
Cc: Namjae Jeon <linkinjeon@kernel.org>
Cc: David Howells <dhowells@redhat.com>
Cc: linux-cifs@vger.kernel.org
Cc: stable@vger.kernel.org
Signed-off-by: Steve French <stfrench@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 fs/cifs/smb2pdu.c |    4 ++++
 1 file changed, 4 insertions(+)
diff mbox series

Patch

--- a/fs/cifs/smb2pdu.c
+++ b/fs/cifs/smb2pdu.c
@@ -4081,6 +4081,10 @@  static inline bool smb3_use_rdma_offload
 	if (server->sign)
 		return false;
 
+	/* we don't support encrypted offload yet */
+	if (smb3_encryption_required(tcon))
+		return false;
+
 	/* offload also has its overhead, so only do it if desired */
 	if (io_parms->length < server->smbd_conn->rdma_readwrite_threshold)
 		return false;