blob: 4fbc50a0a2c4bfd36d1068534c68372ee63c9f4d [file] [log] [blame]
/*
* linux/net/sunrpc/gss_krb5_unseal.c
*
* Adapted from MIT Kerberos 5-1.2.1 lib/gssapi/krb5/k5unseal.c
*
* Copyright (c) 2000-2008 The Regents of the University of Michigan.
* All rights reserved.
*
* Andy Adamson <andros@umich.edu>
*/
/*
* Copyright 1993 by OpenVision Technologies, Inc.
*
* Permission to use, copy, modify, distribute, and sell this software
* and its documentation for any purpose is hereby granted without fee,
* provided that the above copyright notice appears in all copies and
* that both that copyright notice and this permission notice appear in
* supporting documentation, and that the name of OpenVision not be used
* in advertising or publicity pertaining to distribution of the software
* without specific, written prior permission. OpenVision makes no
* representations about the suitability of this software for any
* purpose. It is provided "as is" without express or implied warranty.
*
* OPENVISION DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE,
* INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS, IN NO
* EVENT SHALL OPENVISION BE LIABLE FOR ANY SPECIAL, INDIRECT OR
* CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF
* USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR
* OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
* PERFORMANCE OF THIS SOFTWARE.
*/
/*
* Copyright (C) 1998 by the FundsXpress, INC.
*
* All rights reserved.
*
* Export of this software from the United States of America may require
* a specific license from the United States Government. It is the
* responsibility of any person or organization contemplating export to
* obtain such a license before exporting.
*
* WITHIN THAT CONSTRAINT, permission to use, copy, modify, and
* distribute this software and its documentation for any purpose and
* without fee is hereby granted, provided that the above copyright
* notice appear in all copies and that both that copyright notice and
* this permission notice appear in supporting documentation, and that
* the name of FundsXpress. not be used in advertising or publicity pertaining
* to distribution of the software without specific, written prior
* permission. FundsXpress makes no representations about the suitability of
* this software for any purpose. It is provided "as is" without express
* or implied warranty.
*
* THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
* IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
* WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE.
*/
#include <crypto/algapi.h>
#include <linux/types.h>
#include <linux/jiffies.h>
#include <linux/sunrpc/gss_krb5.h>
#include <linux/crypto.h>
#include "gss_krb5_internal.h"
#if IS_ENABLED(CONFIG_SUNRPC_DEBUG)
# define RPCDBG_FACILITY RPCDBG_AUTH
#endif
u32
gss_krb5_verify_mic_v2(struct krb5_ctx *ctx, struct xdr_buf *message_buffer,
struct xdr_netobj *read_token)
{
struct crypto_ahash *tfm = ctx->initiate ?
ctx->acceptor_sign : ctx->initiator_sign;
char cksumdata[GSS_KRB5_MAX_CKSUM_LEN];
struct xdr_netobj cksumobj = {
.len = ctx->gk5e->cksumlength,
.data = cksumdata,
};
u8 *ptr = read_token->data;
__be16 be16_ptr;
time64_t now;
u8 flags;
int i;
dprintk("RPC: %s\n", __func__);
memcpy(&be16_ptr, (char *) ptr, 2);
if (be16_to_cpu(be16_ptr) != KG2_TOK_MIC)
return GSS_S_DEFECTIVE_TOKEN;
flags = ptr[2];
if ((!ctx->initiate && (flags & KG2_TOKEN_FLAG_SENTBYACCEPTOR)) ||
(ctx->initiate && !(flags & KG2_TOKEN_FLAG_SENTBYACCEPTOR)))
return GSS_S_BAD_SIG;
if (flags & KG2_TOKEN_FLAG_SEALED) {
dprintk("%s: token has unexpected sealed flag\n", __func__);
return GSS_S_FAILURE;
}
for (i = 3; i < 8; i++)
if (ptr[i] != 0xff)
return GSS_S_DEFECTIVE_TOKEN;
if (gss_krb5_checksum(tfm, ptr, GSS_KRB5_TOK_HDR_LEN,
message_buffer, 0, &cksumobj))
return GSS_S_FAILURE;
if (memcmp(cksumobj.data, ptr + GSS_KRB5_TOK_HDR_LEN,
ctx->gk5e->cksumlength))
return GSS_S_BAD_SIG;
/* it got through unscathed. Make sure the context is unexpired */
now = ktime_get_real_seconds();
if (now > ctx->endtime)
return GSS_S_CONTEXT_EXPIRED;
/*
* NOTE: the sequence number at ptr + 8 is skipped, rpcsec_gss
* doesn't want it checked; see page 6 of rfc 2203.
*/
return GSS_S_COMPLETE;
}