[PATCH v1 1/2] cifs: set server->cipher_type to AES-128-CCM for SMB3.0

["Aurélien Aptel" <aaptel@suse.com>]

From: Aurelien Aptel <aaptel@suse.com>

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>
---
 fs/cifs/smb2pdu.c | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/fs/cifs/smb2pdu.c b/fs/cifs/smb2pdu.c
index 9f24eb88297a..c205f93e0a10 100644
--- a/fs/cifs/smb2pdu.c
+++ b/fs/cifs/smb2pdu.c
@@ -958,6 +958,13 @@ SMB2_negotiate(const unsigned int xid, struct cifs_ses *ses)
 	/* 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);
 	/*
-- 
2.31.1