linux/net/sunrpc/auth_gss/gss_krb5_wrap.c

/*
 * COPYRIGHT (c) 2008
 * The Regents of the University of Michigan
 * ALL RIGHTS RESERVED
 *
 * Permission is granted to use, copy, create derivative works
 * and redistribute this software and such derivative works
 * for any purpose, so long as the name of The University of
 * Michigan is not used in any advertising or publicity
 * pertaining to the use of distribution of this software
 * without specific, written prior authorization.  If the
 * above copyright notice or any other identification of the
 * University of Michigan is included in any copy of any
 * portion of this software, then the disclaimer below must
 * also be included.
 *
 * THIS SOFTWARE IS PROVIDED AS IS, WITHOUT REPRESENTATION
 * FROM THE UNIVERSITY OF MICHIGAN AS TO ITS FITNESS FOR ANY
 * PURPOSE, AND WITHOUT WARRANTY BY THE UNIVERSITY OF
 * MICHIGAN OF ANY KIND, EITHER EXPRESS OR IMPLIED, INCLUDING
 * WITHOUT LIMITATION THE IMPLIED WARRANTIES OF
 * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. THE
 * REGENTS OF THE UNIVERSITY OF MICHIGAN SHALL NOT BE LIABLE
 * FOR ANY DAMAGES, INCLUDING SPECIAL, INDIRECT, INCIDENTAL, OR
 * CONSEQUENTIAL DAMAGES, WITH RESPECT TO ANY CLAIM ARISING
 * OUT OF OR IN CONNECTION WITH THE USE OF THE SOFTWARE, EVEN
 * IF IT HAS BEEN OR IS HEREAFTER ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGES.
 */

#include <crypto/skcipher.h>
#include <linux/types.h>
#include <linux/jiffies.h>
#include <linux/sunrpc/gss_krb5.h>
#include <linux/pagemap.h>

#include "gss_krb5_internal.h"

#if IS_ENABLED(CONFIG_SUNRPC_DEBUG)
#define RPCDBG_FACILITY …
#endif

/*
 * We can shift data by up to LOCAL_BUF_LEN bytes in a pass.  If we need
 * to do more than that, we shift repeatedly.  Kevin Coffman reports
 * seeing 28 bytes as the value used by Microsoft clients and servers
 * with AES, so this constant is chosen to allow handling 28 in one pass
 * without using too much stack space.
 *
 * If that proves to a problem perhaps we could use a more clever
 * algorithm.
 */
#define LOCAL_BUF_LEN …

static void rotate_buf_a_little(struct xdr_buf *buf, unsigned int shift)
{ … }

static void _rotate_left(struct xdr_buf *buf, unsigned int shift)
{ … }

static void rotate_left(u32 base, struct xdr_buf *buf, unsigned int shift)
{ … }

u32
gss_krb5_wrap_v2(struct krb5_ctx *kctx, int offset,
		 struct xdr_buf *buf, struct page **pages)
{ … }

u32
gss_krb5_unwrap_v2(struct krb5_ctx *kctx, int offset, int len,
		   struct xdr_buf *buf, unsigned int *slack,
		   unsigned int *align)
{ … }