[PATCH 5.12 012/296] cifs: set server->cipher_type to AES-128-CCM for SMB3.0

Greg Kroah-Hartman
2021-05-31T15:56:14Z

From: Aurelien Aptel <aaptel@suse.com>

commit 6d2fcfe6b517fe7cbf2687adfb0a16cdcd5d9243 upstream.

SMB3.0 doesn't have encryption negotiate context but simply uses
the SMB2_GLOBAL_CAP_ENCRYPTION flag.

When that flag is present in the neg response cifs.ko uses AES-128-CCM
which is the only cipher available in this context.

cipher_type was set to the server cipher only when parsing encryption
negotiate context (SMB3.1.1).

For SMB3.0 it was set to 0. This means cipher_type value can be 0 or 1
for AES-128-CCM.

Fix this by checking for SMB3.0 and encryption capability and setting
cipher_type appropriately.

Signed-off-by: Aurelien Aptel <aaptel@suse.com>
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 | 7 +++++++
1 file changed, 7 insertions(+)

--- a/fs/cifs/smb2pdu.c
+++ b/fs/cifs/smb2pdu.c
@@ -958,6 +958,13 @@ SMB2_negotiate(const unsigned int xid, s
/* Internal types */
server->capabilities |= SMB2_NT_FIND | SMB2_LARGE_FILES;

+ /*
+ * SMB3.0 supports only 1 cipher and doesn't have a encryption neg context
+ * Set the cipher type manually.
+ */
+ if (server->dialect == SMB30_PROT_ID && (server->capabilities & SMB2_GLOBAL_CAP_ENCRYPTION))
+ server->cipher_type = SMB2_ENCRYPTION_AES128_CCM;
+
security_blob = smb2_get_data_area_len(&blob_offset, &blob_length,
(struct smb2_sync_hdr *)rsp);
/*