[CIFS] Add upcall files for cifs to use spnego/kerberos

Acked-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Steve French <sfrench@us.ibm.com>

fs/cifs/cifs_spnego.c

+/*
+ *   fs/cifs/cifs_spnego.c -- SPNEGO upcall management for CIFS
+ *
+ *   Copyright (c) 2007 Red Hat, Inc.
+ *   Author(s): Jeff Layton (jlayton@redhat.com)
+ *
+ *   This library is free software; you can redistribute it and/or modify
+ *   it under the terms of the GNU Lesser General Public License as published
+ *   by the Free Software Foundation; either version 2.1 of the License, or
+ *   (at your option) any later version.
+ *
+ *   This library is distributed in the hope that it will be useful,
+ *   but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See
+ *   the GNU Lesser General Public License for more details.
+ *
+ *   You should have received a copy of the GNU Lesser General Public License
+ *   along with this library; if not, write to the Free Software
+ *   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
+ */
+
+#include <linux/list.h>
+#include <linux/string.h>
+#include <keys/user-type.h>
+#include <linux/key-type.h>
+#include "cifsglob.h"
+#include "cifs_spnego.h"
+#include "cifs_debug.h"
+
+/* create a new cifs key */
+static int
+cifs_spnego_key_instantiate(struct key *key, const void *data, size_t datalen)
+{
+	char *payload;
+	int ret;
+
+	ret = -ENOMEM;
+	payload = kmalloc(datalen, GFP_KERNEL);
+	if (!payload)
+		goto error;
+
+	/* attach the data */
+	memcpy(payload, data, datalen);
+	rcu_assign_pointer(key->payload.data, payload);
+	ret = 0;
+
+error:
+	return ret;
+}
+
+static void
+cifs_spnego_key_destroy(struct key *key)
+{
+	kfree(key->payload.data);
+}
+
+
+/*
+ * keytype for CIFS spnego keys
+ */
+struct key_type cifs_spnego_key_type = {
+	.name		= "cifs.spnego",
+	.instantiate	= cifs_spnego_key_instantiate,
+	.match		= user_match,
+	.destroy	= cifs_spnego_key_destroy,
+	.describe	= user_describe,
+};
+
+/* get a key struct with a SPNEGO security blob, suitable for session setup */
+struct key *
+cifs_get_spnego_key(struct cifsSesInfo *sesInfo, const char *hostname)
+{
+	struct TCP_Server_Info *server = sesInfo->server;
+	char *description, *dp;
+	size_t desc_len;
+	struct key *spnego_key;
+
+
+	/* version + ;ip{4|6}= + address + ;host=hostname + ;sec= + NULL */
+	desc_len = 2 + 5 + 32 + 1 + 5 + strlen(hostname) +
+		   strlen(";sec=krb5") + 1;
+	spnego_key = ERR_PTR(-ENOMEM);
+	description = kzalloc(desc_len, GFP_KERNEL);
+	if (description == NULL)
+		goto out;
+
+	dp = description;
+	/* start with version and hostname portion of UNC string */
+	spnego_key = ERR_PTR(-EINVAL);
+	sprintf(dp, "%2.2x;host=%s;", CIFS_SPNEGO_UPCALL_VERSION,
+		hostname);
+	dp = description + strlen(description);
+
+	/* add the server address */
+	if (server->addr.sockAddr.sin_family == AF_INET)
+		sprintf(dp, "ip4=" NIPQUAD_FMT,
+			NIPQUAD(server->addr.sockAddr.sin_addr));
+	else if (server->addr.sockAddr.sin_family == AF_INET6)
+		sprintf(dp, "ip6=" NIP6_SEQFMT,
+			NIP6(server->addr.sockAddr6.sin6_addr));
+	else
+		goto out;
+
+	dp = description + strlen(description);
+
+	/* for now, only sec=krb5 is valid */
+	if (server->secType == Kerberos)
+		sprintf(dp, ";sec=krb5");
+	else
+		goto out;
+
+	cFYI(1, ("key description = %s", description));
+	spnego_key = request_key(&cifs_spnego_key_type, description, "");
+
+	if (cifsFYI && !IS_ERR(spnego_key)) {
+		struct cifs_spnego_msg *msg = spnego_key->payload.data;
+		cifs_dump_mem("SPNEGO reply blob:", msg->data,
+				msg->secblob_len + msg->sesskey_len);
+	}
+
+out:
+	kfree(description);
+	return spnego_key;
+}

fs/cifs/cifs_spnego.h

+/*
+ *   fs/cifs/cifs_spnego.h -- SPNEGO upcall management for CIFS
+ *
+ *   Copyright (c) 2007 Red Hat, Inc.
+ *   Author(s): Jeff Layton (jlayton@redhat.com)
+ *              Steve French (sfrench@us.ibm.com)
+ *
+ *   This library is free software; you can redistribute it and/or modify
+ *   it under the terms of the GNU Lesser General Public License as published
+ *   by the Free Software Foundation; either version 2.1 of the License, or
+ *   (at your option) any later version.
+ *
+ *   This library is distributed in the hope that it will be useful,
+ *   but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See
+ *   the GNU Lesser General Public License for more details.
+ *
+ *   You should have received a copy of the GNU Lesser General Public License
+ *   along with this library; if not, write to the Free Software
+ *   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
+ */
+
+#ifndef _CIFS_SPNEGO_H
+#define _CIFS_SPNEGO_H
+
+#define CIFS_SPNEGO_UPCALL_VERSION 1
+
+/*
+ * The version field should always be set to CIFS_SPNEGO_UPCALL_VERSION.
+ * The flags field is for future use. The request-key callout should set
+ * sesskey_len and secblob_len, and then concatenate the SessKey+SecBlob
+ * and stuff it in the data field.
+ */
+struct cifs_spnego_msg {
+	uint32_t	version;
+	uint32_t	flags;
+	uint32_t	sesskey_len;
+	uint32_t	secblob_len;
+	uint8_t		data[1];
+};
+
+#ifdef __KERNEL__
+extern struct key_type cifs_spnego_key_type;
+#endif /* KERNEL */
+
+#endif /* _CIFS_SPNEGO_H */