ksmbd: validate session id and tree id in the compound request

This patch validate session id and tree id in compound request.
If first operation in the compound is SMB2 ECHO request, ksmbd bypass
session and tree validation. So work->sess and work->tcon could be NULL.
If secound request in the compound access work->sess or tcon, It cause
NULL pointer dereferecing error.

Cc: stable@vger.kernel.org
Reported-by: zdi-disclosures@trendmicro.com # ZDI-CAN-21165
Signed-off-by: Namjae Jeon <linkinjeon@kernel.org>
Signed-off-by: Steve French <stfrench@microsoft.com>

1 files changed, 20 insertions, 13 deletions

diff --git a/fs/smb/server/server.c b/fs/smb/server/server.c
index f9b2e0f19b03..ced7a9e916f0 100644
--- a/fs/smb/server/server.c
+++ b/fs/smb/server/server.c
@@ -185,24 +185,31 @@ static void __handle_ksmbd_work(struct ksmbd_work *work,
 		goto send;
 	}
 
-	if (conn->ops->check_user_session) {
-		rc = conn->ops->check_user_session(work);
-		if (rc < 0) {
-			command = conn->ops->get_cmd_val(work);
-			conn->ops->set_rsp_status(work,
-					STATUS_USER_SESSION_DELETED);
-			goto send;
-		} else if (rc > 0) {
-			rc = conn->ops->get_ksmbd_tcon(work);
+	do {
+		if (conn->ops->check_user_session) {
+			rc = conn->ops->check_user_session(work);
 			if (rc < 0) {
-				conn->ops->set_rsp_status(work,
-					STATUS_NETWORK_NAME_DELETED);
+				if (rc == -EINVAL)
+					conn->ops->set_rsp_status(work,
+						STATUS_INVALID_PARAMETER);
+				else
+					conn->ops->set_rsp_status(work,
+						STATUS_USER_SESSION_DELETED);
 				goto send;
+			} else if (rc > 0) {
+				rc = conn->ops->get_ksmbd_tcon(work);
+				if (rc < 0) {
+					if (rc == -EINVAL)
+						conn->ops->set_rsp_status(work,
+							STATUS_INVALID_PARAMETER);
+					else
+						conn->ops->set_rsp_status(work,
+							STATUS_NETWORK_NAME_DELETED);
+					goto send;
+				}
 			}
 		}
-	}
 
-	do {
 		rc = __process_request(work, conn, &command);
 		if (rc == SERVER_HANDLER_ABORT)
 			break;